HMKCode

Testing Expected Exceptions (JUnit)

hani.hmk — Mon, 20 May 2013 17:07:03 +0000

When we test, we expect some exceptions to take place. Here we will see different ways to test methods with expected exceptions.

Objectives:

How to write test cases that test expected exceptions?

Environment & Tools:

Eclipse
Maven

Libraries:

JUnit (4.11)
hamcrest-core (1.3)

For complete list of jar files: .classpath
For complete list of Maven dependencies: pom.xml

( 1 ) Simple Test

This is enough to test simple cases.

Here we initiate a String variable with null, then we try to apply toUpperCase() method. We know that it should throw NullPointerException or we expected it!

package com.hmkcode;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

@RunWith(JUnit4.class)
public class AppTest 
{
	 @Test(expected= NullPointerException.class) 
	  public void testNull() { 
	       String str = null;
	       str.toUpperCase();
	  } 	
}

( 2 ) Test Exception Message

Here is a more advanced way to test expected exception. We use Try/catch if the exception we expected is not thrown the test will fail. Also, if we did not get the expected exception message the test will fail.

package com.hmkcode;

import java.util.LinkedList;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
import static org.junit.Assert.assertThat;
import static org.junit.Assert.fail;
import static org.hamcrest.CoreMatchers.is;

@RunWith(JUnit4.class)
public class AppTest 
{
	 @Test
	 public void testExceptionMessage(){
		 try{
			 new LinkedList().get(0);

			 //if no exception thrown the test will fail with the below message.
			 fail("Expected an IndexOutOfBoundsException to be thrown");

	      } catch (IndexOutOfBoundsException anIndexOutOfBoundsException) {

	    	  //if no exception message is not the same the test will fail with the below message.
	          assertThat(anIndexOutOfBoundsException.getMessage(), is("Index: 0, Size: 0"));
	      }

	 }
}

( 3 ) Using @Rule

We have another way to test expected exception and expected exception message, it is @Rule

package com.hmkcode;

import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;

@RunWith(JUnit4.class)
public class AppTest 
{
  	  @Rule
	  public ExpectedException thrown = ExpectedException.none();

	  @Test
	  public void testExceptionByRule() throws ArithmeticException {

	        thrown.expect(ArithmeticException.class);
	        thrown.expectMessage("/ by zero");

	    	double d = 1 / 0;
	   }

}

Source Code @ GitHub

Spring Profile XML Configuration

hani.hmk — Sun, 19 May 2013 20:37:35 +0000

If you like to load environment specific spring configuration you can do this using profile. In other words, if you want to load a set of beans that have different settings on different environment (development, testing or production) you can use profile feature instead of pointing to a different spring xml configuration at each stage.

Objective:

How to use profile in spring xml configuration?

Environment & Tools:

Eclipse
Maven (optional)

Libraries:

Spring framework

For complete list of jars: .classpath
For complete list of dependencies: pom.xml

Source Code @ GitHub

( 1 ) Two Spring XML Config (non-profile-way)

Assume we have two different spring xml configuration files and we want to load each one of them on a different environment “one for development and one for production”.

1. spring-config-development.xml

2. spring-config-production.xml

One solution is to explicitly point to each one when we move from one environment to another.

On development

public class App 
{
    public static void main( String[] args )
    {

    	ClassPathXmlApplicationContext ctx = 
        new ClassPathXmlApplicationContext("spring-config-development.xml");
        Person person =  (Person)ctx.getBean("person");
        System.out.println("Person: "+person);
    }
}

On Production

public class App 
{
    public static void main( String[] args )
    {

    	ClassPathXmlApplicationContext ctx = 
        new ClassPathXmlApplicationContext("spring-config-production.xml");
        Person person =  (Person)ctx.getBean("person");
        System.out.println("Person: "+person);
    }
}

( 2 ) Using profile

Spring 3.1 has introduced “profile” the environment aware feature.

To use profile, we need to add profile property to in xml file.

1. spring-config-development.xml

2. spring-config-production.xml

Now, in the main class we need to use GenericXmlApplicationContext since it allows us to point to more than one xml files. The question now is which xml to load? we can specify which xml to load by setting the active profile

either System.setProperty(“spring.profiles.active”, “development”);
or ctx.getEnvironment().setActiveProfiles(“development”);

package com.hmkcode;

import org.springframework.context.support.GenericXmlApplicationContext;
import org.springframework.core.env.ConfigurableEnvironment;
import com.hmkcode.vo.Person;

public class App 
{
    public static void main( String[] args )
    {

    	System.setProperty("spring.profiles.active", "development"); //or production
    	GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();

    	ctx.load("spring-config-development.xml","spring-config-production.xml");

    	// Alternative way to set the active profile
    	//ctx.getEnvironment().setActiveProfiles("development"); //or production
    	ctx.refresh();

        Person person =  (Person)ctx.getBean("person");
        System.out.println("Person: "+person);
    }
}

One further enhancement is to combine all xml files into one file as following:

spring-config-all.xml

Now, we can also change java code as following

package com.hmkcode;

import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.hmkcode.vo.Person;

public class App 
{
    public static void main( String[] args )
    {

    	System.setProperty("spring.profiles.active", "development"); //or production
    	ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("spring-config-all.xml");

        Person person =  (Person)ctx.getBean("person");
        System.out.println("Person: "+person);
    }
}

Android Studio – Hello World!

hani.hmk — Sat, 18 May 2013 19:58:01 +0000

Building your first app with the new Android Studio.

Objectives:

Install Android Studio for Windows
Build Hello World App

Environment:

Windows
Java JDK

( 1 ) Download the new IDE

http://developer.android.com/sdk/installing/studio.html#download
Click on the “Download Android Studio” button

( 2 ) Install the IDE

Lunch the downloaded .exe file
Follow the installation instructions.

( 3 ) New Project

After completing the installation select “New Project”

Enter Application Name: Hello World
Keep other default settings.
Next (3 times)
Finish

It may take some time in the first time

( 4 ) Generated Project

( 5 ) Run the App

Choose a running device “You need to plugin in android device”
or emulator

SQL Maven Plugin (MySQL)

hani.hmk — Fri, 17 May 2013 19:57:11 +0000

If you like to automate repetitive tasks with database you can achieve this using Maven SQL plugin. Simply it does for you whatever you need to do with a database at any given phase of Maven life-cycle.

Objective:

How to use SQL Maven plugin with MySQL or other db?

Environment:

Maven
MySQL (for this example)

Libraries:

SQL Maven plugin

( 1 ) What we will be doing in this example?

As mentioned above, this plugin is about doing somethings with a database (MySQL for example) at a given phase. Here we will do three things with MySQL at test phase (actually before going into the test phase).

We would like to do the following before running our test class.

Drop “person” table if exists.
Create “person” table.
Insert some data into “person” table.

( 2 ) pom.xml

All what we need to do will go into pom.xml file between the …

With in the … we need to add 4 things

Plugin info , &
JDBC Driver
DB connection
at a certain this , or


        
        org.codehaus.mojo
        sql-maven-plugin
        1.5

        
        
                
                        mysql
                        mysql-connector-java
                        5.1.9
                
        

      
      
          com.mysql.jdbc.Driver
          jdbc:mysql://localhost:3306/hmkcode
          root
          
        

      
      
          
            drop-table
            process-test-resources
            
              execute
            
            
              true
              DROP TABLE IF EXISTS person
            
          
         .......

( 3 ) Analyzing

: just unique name
: at what phase this will run
: what goal to call sql:execute
: read more about Optional Parameters
: read more about it…
: SQL statement to execute

Now, for the last tag we have other option which is passing sql file.

( 4 ) Complete Code

pom.xml


  4.0.0

  com.hmkcode
  maven-sql-plugin
  1.0-SNAPSHOT
  jar

  maven-sql-plugin
  http://maven.apache.org

  
    UTF-8
  

  
    
      junit
      junit
      4.11
      test
    
  



      
        org.codehaus.mojo
        sql-maven-plugin
        1.5

        
				
						mysql
						mysql-connector-java
						5.1.9
				
		

        
          com.mysql.jdbc.Driver
          jdbc:mysql://localhost:3306/hmkcode
          root
          
        

        
          
            drop-table
            process-test-resources
            
              execute
            
            
              true
              DROP TABLE IF EXISTS person
            
          

          
            create-table
            process-test-resources
            
              execute
            
            
              true
			  
                src/main/sql/schema.sql
              
            
          

          
            insert-data
            process-test-resources
            
              execute
            
            
              ascending
              
                ${basedir}
                
                  src/test/sql/test-data.sql

/src/main/sql/schema.sql

CREATE TABLE person (id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(255));

/src/test/sql/test-data.sql

INSERT INTO person (name) VALUES ('person-1');
INSERT INTO person (name) VALUES ('person-2');
INSERT INTO person (name) VALUES ('person-3');
INSERT INTO person (name) VALUES ('person-4');
INSERT INTO person (name) VALUES ('person-5');
INSERT INTO person (name) VALUES ('person-6');

To run in example you need to have MySQL running on localhost and to create a database hmkcode. Actually we can add an that creates the database for us

Open command prompt, navigate to the project directory “maven-sql-plugin” and type:

./maven-sql-plugin>mvn test

Source Code @ GitHub

MyBatis + Spring + Junit (The Missing Part)

hani.hmk — Thu, 16 May 2013 07:57:22 +0000

We have seen in Mybatis + Spring (XML | Annotation) Mapper how to write a simple mybatis-spring app and what is actually needed to get it up and running. Here I will extend that sample code to cover more stuff that you may face in a real “coding”. We will see how to make a single select that will fetch the one and the many of a “one-to-many” relationship, who to use mybatis config file with spring (if you need it), how to test mybatis-spring code using junit and things you need to watch out!

H2 embedded database has been used to make this example easy to run. But you still can use it with other databases e.g. “MySql, Oracle,….”

Objectives:

How to use make a single select that will fetch all one to many records?
How to reference mybatis config file in spring xml config file?
How to test using junit?

Environment:

Eclipse
Maven

Libraries:

Spring Framework
MyBatis
MyBatis for Spring
Junit (4.11)
H2

For complete list of jar files: .classpath
For complete list of : pom.xml

( 1 ) Project Structure

This project was generated using Maven and converted into Eclipse.

Database tables structure

Two tables (parent & child)

CREATE TABLE parent (parentId INT PRIMARY KEY AUTO_INCREMENT, parentName VARCHAR(255));
CREATE TABLE child (childId INT PRIMARY KEY AUTO_INCREMENT, parentId INT, childName VARCHAR(255));

( 2 ) What to Code?

spring-config.xml (required)
Mapper.java & Mapper.xml (required)
mybatis-config.xml (optional) as needed!
Service.java (decorator) make our code cleaner! you may call it e.g. Factory.java
Parent.java & Child.java (model, beans or entities) for this example.
Schema.sql & test-data.sq (data model & sample data) for this example. Used by H2 db on instantiation! (H2 create tables and fill it with data when we start the app and destroy them when we close the app)
App.java (main class) run our example
AppTest.java (test class)

src/main/resources/spring-config.xml

src/main/java/com/hmkcode/spring/mybatis/mapper/Mapper.java

package com.hmkcode.spring.mybatis.mapper;

import java.util.List;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;
import com.hmkcode.spring.mybatis.vo.Child;
import com.hmkcode.spring.mybatis.vo.Parent;;

public interface Mapper {

	//if @Select is used table/column name and class/property name should be the same

	//SQL query in "Mapper.xml"
	public List selectAllParent();

	//SQL query in "Mapper.xml"
	public Parent selectParent(@Param("id") int id);

	@Insert("INSERT INTO parent (parentName) VALUES (#{parentName})")
	public int insertParent(Parent parent);

	@Select("SELECT * FROM child WHERE parentId = #{id}")
	public List selectAllChildren(@Param("id") int id);

	@Select("SELECT * FROM child WHERE childId = #{id}")
	public Child selectChild(@Param("id") int id);

	//SQL query in "Mapper.xml"
	public int insertchild(Child child);		
}

src/main/resources/com/hmkcode/spring/mybatis/mapper/Mapper.xml

Notice the use of this will fetch all children of when each parent is fetched






	
	
		
			

		
		
	

	
	
		
		
		
	

	

	
	

	
	

	
	
		INSERT INTO child
			(parentId,childName)
			VALUES 
			(#{parentId},#{childName})

src/main/resources/com/hmkcode/spring/mybatis//mybatis-config.xml

Why we you need this file?

We want to create aliases for “model” classes (Parent.java & Child.java) so when we need to refer to them we don’t need to write the complete namespace “package+class name” e.g. in the Mapper.xml we refer to Child in Child” timeout=”10″> if we did not create the aliases in mybatis-config.xml we would write the following com.hmkcode.spring.mybatis.vo.Child” timeout=”10″>

Now, for the aliases either to specify classes full name or the their package. If you specify the package, classes should be annotated with @Alias(“….”).

src/main/java/com/hmkcode/spring/mybatis/service/Service.java

package com.hmkcode.spring.mybatis.service;

import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import com.hmkcode.spring.mybatis.mapper.Mapper;
import com.hmkcode.spring.mybatis.vo.Child;
import com.hmkcode.spring.mybatis.vo.Parent;

public class Service {

	@Autowired 
	private Mapper mapper;

	public List selectAllParent(){
		return mapper.selectAllParent();
	}

	public Parent selectParent(int id){
		return mapper.selectParent(id);
	}

	public int insertParent(Parent parent){
		return mapper.insertParent(parent);
	}

	public List selectAllChildren(int parnetId){
		return mapper.selectAllChildren(parnetId);
	}

	public Child selectChild(int id){
		return mapper.selectChild(id);
	}

	public int insertchild(Child child){
		return mapper.insertchild(child);
	}
}

src/main/java/com/hmkcode/spring/mybatis/vo/Parent.java

package com.hmkcode.spring.mybatis.vo;

import java.util.List;
import org.apache.ibatis.type.Alias;

@Alias("Parent")
public class Parent {

	private int parentId;
	private String parentName;

	private List children;

	//setters & getters

	public String toString(){
		return "\nParent [ id: "+this.parentId+" - name: "+this.parentName+" \n" +
						"\tchildren: "+this.children+
				"\n]"; 
	}
}

src/main/java/com/hmkcode/spring/mybatis/vo/Child.java

package com.hmkcode.spring.mybatis.vo;

import org.apache.ibatis.type.Alias;

@Alias("Child")
public class Child extends Parent
{
	private int childId;
   	private String childName;

   	//setters & getters

	public String toString(){
		return "Child [ id: "+this.childId+" - name: "+this.childName+" (PARENT_ID :"+this.getParentId()+") ]"; 
	}
}

src/main/resources/schema.xml

CREATE TABLE parent (parentId INT PRIMARY KEY AUTO_INCREMENT, parentName VARCHAR(255));
CREATE TABLE child (childId INT PRIMARY KEY AUTO_INCREMENT, parentId INT, childName VARCHAR(255));

src/main/resources/test-data.xml

INSERT INTO parent (parentName) VALUES ('parent-1')
INSERT INTO parent (parentName) VALUES ('parent-2')
INSERT INTO parent (parentName) VALUES ('parent-3')

INSERT INTO child (childName,parentId) VALUES ('child-1',1)
INSERT INTO child (childName,parentId) VALUES ('child-2',1)
INSERT INTO child (childName,parentId) VALUES ('child-3',2)

src/main/java/com/hmkcode/spring/mybatis/App.java

package com.hmkcode.spring.mybatis;

import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import com.hmkcode.spring.mybatis.service.Service;
import com.hmkcode.spring.mybatis.vo.Child;
import com.hmkcode.spring.mybatis.vo.Parent;

public class App 
{
	private static Log log = LogFactory.getLog(App.class);

    public static void main( String[] args )
    {

    	ApplicationContext cxt = new ClassPathXmlApplicationContext("spring-config.xml");
    	Service service = (Service) cxt.getBean("service");

    	log.info("Running App...");

    	//( 1 ) SELECT ALL PARENTS
    	System.out.println("( 1 ) selectAllParent()");
    	List parents = service.selectAllParent();
    	System.out.println("-> "+parents);

    	System.out.println("****************************************************");

    	//( 2 ) SELECT ONE PARENT
    	System.out.println("( 2 ) selectParent(2)");
    	Parent parent = service.selectParent(2);
    	System.out.println("-> "+parent);

    	System.out.println("****************************************************");

    	//( 3 ) INSERT ONE PARENT
    	System.out.println("( 3 ) insertParent(parent)");
    	parent = new Parent();
    	parent.setParentName("parent-4 inserted");
    	service.insertParent(parent);
    	System.out.println("-> parent inserted");

    	System.out.println("****************************************************");

    	//( 4 ) SELECT ALL CHILDREN OF A GIVEN PARENT
    	System.out.println("( 4 ) selectAllChildren(parentId)");
    	List children = service.selectAllChildren(1);
    	System.out.println("-> "+children);

    	System.out.println("****************************************************");

    	//( 5 ) SELECT ONE CHILD
    	System.out.println("( 5 ) selectChild(1)");
    	Child child = service.selectChild(1);
    	System.out.println("-> "+child);

    	System.out.println("****************************************************");

    	//( 6 ) INSERT ONE CHILD
    	System.out.println("( 6 ) selectAllChildren(parentId)");
    	child = new Child();
    	child.setChildName("child-4 inserted");
    	child.setParentId(2);
    	service.insertchild(child);
    	System.out.println("-> child inserted");

    	System.out.println("****************************************************");

    	//( 7 ) SELECT ALL PARENTS (AGAIN!)
    	System.out.println("( 7 ) selectAllParent()");
    	parents = service.selectAllParent();
    	System.out.println("-> "+parents);

    }
}

src/test/java/com/hmkcode/spring/mybatis/AppTest.java

package com.hmkcode.spring.mybatis;

import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import com.hmkcode.spring.mybatis.service.Service;
import com.hmkcode.spring.mybatis.vo.Parent;

import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertTrue;;

/**
 * Unit test for simple App.
 */

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "/spring-config.xml")
public class AppTest {

	private static Log log = LogFactory.getLog(AppTest.class);

	@Autowired private Service service;

	@Test
	public void testSelectAllParent(){
		log.info("testing selectAllParent()...");

		List parents = service.selectAllParent();

		assertNotNull("failure - parents is null", parents);

		assertTrue("failure - expected 3 parents", parents.size() == 3);

		assertTrue("failure - expected 2 children", parents.get(0).getChildren().size() == 2);

		log.info(parents);
	}

	@Test
	public void testSelectParent(){
		log.info("testing selectParent()...");
		int parentId = 2;
		String parentName = "parent-2";
		Parent parent = service.selectParent(parentId);

		assertNotNull("failure - parents is null", parent);

		assertTrue("failure - parent name is not right", parent.getParentName().equals(parentName));

		assertTrue("failure - expected 1 child", parent.getChildren().size() == 1);
	}

	@Test
	public void testInsertParent(){

		log.info("testing insertParent()...");

		int parentId = 4;
		String parentName = "parent-4 inserted";

		Parent parent = new Parent();
		parent.setParentName(parentName);

		service.insertParent(parent);

		parent = service.selectParent(4);

		assertNotNull("failure - parents is null", parent);

		assertTrue("failure - parent name is not right", parent.getParentName().equals(parentName));

		assertTrue("failure - expected 0 child", parent.getChildren().size() == 0);

	}
}

( 3 ) Run & Test

Now you have many ways to run or test this sample code. This sample code is ready to run, no need to make any configuration if you have Maven setup on you machine. If you don’t, you need to add the needed jar files to the classpath.

Using Maven:

To run App.java

../spring-mybatis-junit>mvn exec:java

To run AppTest.java

../spring-mybatis-junit>mvn test

Using Eclipse:

Convert Maven project to Eclipse

../spring-mybatis-junit>mvn eclipse:eclipse

To run App.java

Right Click App.java >> Run As >> Java Application

To run AppTest.java

Right click AppTest.java >> Run As >> Junit Test

Source Code @ GitHub

Spring MVC + jQuery File Upload (multiple, drag&drop, progress…)

hani.hmk — Thu, 09 May 2013 14:58:11 +0000

jQuery-File-Upload js library is “so far” the most elegant, smart, simple..etc js library I have used to upload files. Simply it is amazing. It supports async upload “Ajax”, multiple files upload, drag&drop, progress update and a lot more. Here we will see an example of uploading multiple files to Spring MVC app. Bootstrap has been used in this example to make the UI more attractive.

Try Simple Demo

Objectives:

How to upload single or multiple files using jquery.fileupload.js?

Environment:

Firefox & Chrome (IE was not tested!)
Maven
Eclipse
Jetty (or other java server)

Libraries:

Java Libraries:

Spring Framework
Apache common io & fileupload
Jackson
Common logging
Other

check .classpath file for complete list of jars

pom.xml

	
		
			org.springframework
			spring-core
			${spring.version}
		
		
			org.springframework
			spring-web
			${spring.version}
		
		
			org.springframework
			spring-webmvc
			${spring.version}
		
		
			javax.servlet
			servlet-api
			2.5
		
		
		commons-fileupload
			commons-fileupload
			1.2
		
	    
			commons-io
			commons-io
			2.4
		
        
		org.codehaus.jackson
			jackson-mapper-asl
			1.9.12
		
        
			org.codehaus.jackson
			jackson-core-asl
			1.9.12

Javascript Libraries:

The example was designed to run with simple Maven command, just download the source code and run it.

>mvn jetty:run

( 1 ) Backend – Java Project “Spring MVC”

This project was generate using Maven and converted into Eclipse

For the backend we have:

2 Java files (FileController.java & FileMeta.java)
2 XML files (rest-servlet.xml & web.xml)

src/main/java/com/hmkcode/spring/mvc/controllers/FileController.java

package com.hmkcode.spring.mvc.controllers;

import java.io.IOException;
import java.util.Iterator;
import java.util.LinkedList;
import javax.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Controller;
import org.springframework.util.FileCopyUtils;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;
import com.hmkcode.spring.mvc.model.FileMeta;

@Controller
@RequestMapping("/controller")
public class FileController {

	LinkedList files = new LinkedList();
	FileMeta fileMeta = null;
	/***************************************************
	 * URL: /rest/controller/upload  
	 * upload(): receives files
	 * @param request : MultipartHttpServletRequest auto passed
	 * @param response : HttpServletResponse auto passed
	 * @return LinkedList as json format
	 ****************************************************/
	@RequestMapping(value="/upload", method = RequestMethod.POST)
	public @ResponseBody LinkedList upload(MultipartHttpServletRequest request, HttpServletResponse response) {

		//1. build an iterator
		 Iterator itr =  request.getFileNames();
		 MultipartFile mpf = null;

		 //2. get each file
		 while(itr.hasNext()){

			 //2.1 get next MultipartFile
			 mpf = request.getFile(itr.next()); 
			 System.out.println(mpf.getOriginalFilename() +" uploaded! "+files.size());

			 //2.2 if files > 10 remove the first from the list
			 if(files.size() >= 10)
				 files.pop();

			 //2.3 create new fileMeta
			 fileMeta = new FileMeta();
			 fileMeta.setFileName(mpf.getOriginalFilename());
			 fileMeta.setFileSize(mpf.getSize()/1024+" Kb");
			 fileMeta.setFileType(mpf.getContentType());

			 try {
				fileMeta.setBytes(mpf.getBytes());
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			 //2.4 add to files
			 files.add(fileMeta);
		 }
		// result will be like this
		// [{"fileName":"app_engine-85x77.png","fileSize":"8 Kb","fileType":"image/png"},...]
		return files;
	}
	/***************************************************
	 * URL: /rest/controller/get/{value}
	 * get(): get file as an attachment
	 * @param response : passed by the server
	 * @param value : value from the URL
	 * @return void
	 ****************************************************/
	@RequestMapping(value = "/get/{value}", method = RequestMethod.GET)
	 public void get(HttpServletResponse response,@PathVariable String value){
		 FileMeta getFile = files.get(Integer.parseInt(value));
		 try {		
			 	response.setContentType(getFile.getFileType());
			 	response.setHeader("Content-disposition", "attachment; filename=\""+getFile.getFileName()+"\"");
		        FileCopyUtils.copy(getFile.getBytes(), response.getOutputStream());
		 }catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
		 }
	 }
}

src/main/java/com/hmkcode/spring/mvc/model/FileMeta.java

package com.hmkcode.spring.mvc.model;

import org.codehaus.jackson.annotate.JsonIgnoreProperties;

//ignore "bytes" when return json format
@JsonIgnoreProperties({"bytes"}) 
public class FileMeta {

	private String fileName;
	private String fileSize;
	private String fileType;

	private byte[] bytes;

         //setters & getters
}

src/main/webapp/WEB-INF/web.xml



  Archetype Created Web Application
  
    index.html
  

  
  	rest            
  	org.springframework.web.servlet.DispatcherServlet
  
  
  	rest
  	/rest/*

src/main/webapp/WEB-INF/rest-servlet.xml

( 2 ) Frontend (HTML, CSS, JS)

1 HTML file (index.html)
1 JS file (myuploadfunction.js)
1 CSS file (dropzone.css)

Other .js, .css, images files are downloaded

/scr/main/webapp/index.html





jQuery File Upload Example
















Spring MVC - jQuery File Upload


    

    Drop files here

    
        
    

    
        
            
            
            
            
        
    File Name File Size File Type Download

/scr/main/webapp/js/myuploadfunction.js

$(function () {
    $('#fileupload').fileupload({
        dataType: 'json',

        done: function (e, data) {
        	$("tr:has(td)").remove();
            $.each(data.result, function (index, file) {

                $("#uploaded-files").append(
                		$('')
                		.append($('').text(file.fileName))
                		.append($('').text(file.fileSize))
                		.append($('').text(file.fileType))
                		.append($('').html("Click"))
                		)//end $("#uploaded-files").append()
            }); 
        },

        progressall: function (e, data) {
	        var progress = parseInt(data.loaded / data.total * 100, 10);
	        $('#progress .bar').css(
	            'width',
	            progress + '%'
	        );
   		},

		dropZone: $('#dropzone')
    });
});

/scr/main/webapp/css/dropzone.css

#dropzone {
    background: #ccccc;
    width: 150px;
    height: 50px;
    line-height: 50px;
    text-align: center;
    font-weight: bold;
}
#dropzone.in {
    width: 600px;
    height: 200px;
    line-height: 200px;
    font-size: larger;
}
#dropzone.hover {
    background: lawngreen;
}
#dropzone.fade {
    -webkit-transition: all 0.3s ease-out;
    -moz-transition: all 0.3s ease-out;
    -ms-transition: all 0.3s ease-out;
    -o-transition: all 0.3s ease-out;
    transition: all 0.3s ease-out;
    opacity: 1;
}

( 3 ) Run the Example

./spring-mvc-jquery-file-upload>mvn jetty:run

http://localhost:8080/spring-mvc-jquery-file-upload/

Source Code @ github

Try Demo deployed on Jelastic

Create Your Own Maven archetype (Spring MVC)

hani.hmk — Wed, 08 May 2013 20:43:38 +0000

Maven gives the ability to build a new project from a predefined archetype templates i.e. it generates for us the basic files so we can start coding right away. However, sometimes we need to have our customized version of these templates, fortunately Maven gives us the ability to create those templates which will be used to build our projects.

Objectives:

How to create a new Maven archetype?
Build Spring MVC archetype.

Environment:

Maven

To create a new archetype, we need the following files and directories:

pom.xml: just like any other Maven project we need pom.xml for this archetype to be recognized by Maven. This will be placed under [root_directory]/pom.xml.
archetype-metadata.xml : this will define the structure of our Maven project and what files should be created & in which location. This will be placed under [root_directory]/src/main/resources/META-INF/maven/archetype-metadata.xml.
Prototypes files “files that will be generated for us” should be located under [root_directory]/src/main/resources/archetype-resources/…

For this example [root_directory] will be archetype-spring-mvc

Minimum directory structure and files

Create a new folder “archetype-spring-mvc”

( 1 ) pom.xml

archetype-spring-mvc/pom.xml


  4.0.0

  com.hmkcode.archetypes
  spring-mvc
  1.0-SNAPSHOT
  jar

& pick your own names. These will be used later to call this archetype when generating a new Maven project.

( 2 ) archetype-metadata.xml

We want our archetype to generate for us some basic sample working files, so we can run the generated Maven project directory after it get generated.

As, we know to run webapp we need web.xml and a single index.jsp. For Spring MVC we need spring xml configuration file “spring-servlet.xml” and a single controller “MyController.java“. Also, we need to get our pom.xml generated with the needed dependencies.

Now, in archetype-metadata.xml we need to specify what files we want to be generated for us, and where Maven can find them in our arhcetype template.


    
        
            src/main/java
            
                **/*.java
            
        
        
        src/main/resources
        
        
            src/main/webapp
        
        
            src/test/java
        
            **/*.java
        
        
        
            src/test/resources

( 3 ) Prototypes Files

All files we want to be generated for us are prototypes files, i.e. all files specified in the archetype-metadata.xml. One more important files that not needed to be specified in the archetype-meta.xml is pom.xml but one thing to notice is that , & should be set as variables.

pom.xml

${groupId}
  ${artifactId}
  ${version}

For, java files we can add a $package variable to set the package for them on generation.

( 4 ) Install

Now, we need to install this new archetype to our local maven repository so we can call later.

./archetype-spring-mvc> mvn install

( 5 ) Create Maven Project

>mvn archetype:generate 
-DarchetypeGroupId=com.hmkcode.archetypes 
-DarchetypeArtifactId=spring-mvc 
-DarchetypeVersion=1.0-SNAPSHOT 
-DgroupId=com.hmkcode //this can be changed
-DartifactId=my-spring-mvc //this can be changed

( 6 ) Run

The pom.xml includes Jetty plugin so that you can directly run the generated project.
It also include Jackson dependency so controller can return json.

./my-spring-mvc> mvn jetty:run

Source Code @ github

Create Web App Using Maven, Add Jetty Plugin & Convert to Eclipse

hani.hmk — Tue, 07 May 2013 19:33:33 +0000

Using Maven you can create the foundation for a java web project with a simple command. Also, you can run it easily using Jetty Maven plugin.

Objectives:

How to create web app project using maven?
How to run it using Jetty Maven plugin?
How to convert Maven project into Eclipse project?

Environment:

Apache Maven
Eclipse
JDK 1.6

( 1 ) Create an Empty Web App from Maven Template

Open command prompt
Navigate to the location where you want to create the project at e.g. “C:\Workspace\Maven_Projects”
Type the following command and press enter.

>mvn archetype:generate 
-DgroupId=com.hmkcode //enter your group id
-DartifactId=hello-webapp //enter your articfact id
-DarchetypeArtifactId=maven-archetype-webapp //this should be the same
-DinteractiveMode=false

Now, you should get the following project created with the same directory structure and 3 files “web.xml, index.js and pom.xml”

( 2 ) Add Jetty Maven Plugin

To add Jetty Maven plugin we need to add the following to pom.xml


	  hello-webapp
	  
		          
			  org.mortbay.jetty        
			  maven-jetty-plugin        
			  6.1.10        
			  
				10

The final pom.xml should look like this


  4.0.0
  com.hmkcode
  hello-webapp
  war
  1.0-SNAPSHOT
  hello-webapp Maven Webapp
  http://maven.apache.org
  
    
      junit
      junit
      3.8.1
      test
    
  
  
	  hello-webapp
	  
		          
			  org.mortbay.jetty        
			  maven-jetty-plugin        
			  6.1.10        
			  
				10

( 3 ) Jetty:Run

Now, to run jetty just type the following command

>mvn jetty:run

Once Jetty is up, open your web browser and type: http://localhost:8080/hello-webapp/

( 3 ) Convert to Eclipse

To have better editing for the project you can imported to Eclipse.
To convert Maven based project into Eclipse project we can run the following Maven command:

>mvn eclipse:eclipse -Dwtpversion=2.0

Before, executing the command add the following to pom.xml under


          maven-compiler-plugin
          
                1.6
                1.6

Now, open Eclipse> File >> Import.. >> General >> Existing Project into Workspace
Select the project “hello-webapp”
Finish

You can Import it as an existing General project or as an existing Maven project if you have m2e Maven eclipse plugin installed on your eclipse.

Mybatis + Spring (XML | Annotation) Mapper

hani.hmk — Fri, 03 May 2013 19:43:34 +0000

Here we will see what we need to do to connect to a relational database “MySql, Oracle, H2..etc” using myBatis with Spring framework & how to implement mappers using xml or annotation such as @Select, @Insert,….etc. For the sake of simplicity I have used H2 embedded database so you can run the sample code. However, you can use this sample code to run with MySql or any other relational database.

Source Code @ github

Note: If you have Maven you can run this sample code directly using 
../spring-mybatis>mvn exec:java

Objectives:

How to use MyBatis with Spring framework?
How to implement mapper using xml or annotation @Select, @Insert…?

Environment:

Eclipse
Maven (optional to get need jar files)
H2 embedded database (MySql or Oralce)

Libraries:

refer to pom.xml or .classes for the complete list of dependencies/jar files.

To use mybatis + Spring you need two things;

Spring xml config files to create “datasoruce, sqlSessionFactory & Mapper”
Java interface or “Mapper” + (if needed) an xml file “contains sql statements”

( 1 ) Java Project Structure

The structure is following Maven default structure, however you can change it.

Database table structure for this example is as following

CREATE TABLE person (id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(255));

( 2 ) Spring-config.xml

Here we need to define 3 beans

datasource
sqlSessionFactory
Mapper

For step 1:

It is the only place you need to change if you would like to use another database. For example if we want to use MySql we will change the datasource part as following:

Note: If you want to use MySql do not forget to add the mysql jdbc driver “jar” to the classpath or dependency to pom.xml.

For step 2:

We are passing datasource created in step 1 as property of SqlSessionFactoryBean class. Nothing else need to be done! really easy

For step 3:

Here we will pass two things the sqlSessionFactory from step 2 + java interface “Mapper.java” which we are going to code!

( 3 ) Mapper.java (Java Interface) + XML file (if needed)

Mapper is the place where we are going to link to our SQL statement written within xml file or in annotations.
If you need to write SQL statement in XML, then you need to add the xml file in the same class path as the java interface.

Mapper.java

package com.hmkcode.spring.mybatis.mapper;

import java.util.List;

import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;

import com.hmkcode.spring.mybatis.vo.Person;


public interface Mapper {

	  
	/******************************************
	* Retrieves the List of person 
	* @return person list
	*/
	//SQL query in xml "Mapper.xml"
	public List selectAllPerson();
	/******************************************
    * Retrieves a person 
    * @param person id
    * @return person
    */
    //SQL query using annotation
    @Select("SELECT * FROM person")
    public List selectAllPerson2();
  
    /******************************************
    * Retrieves a person 
    * @param person id
    * @return person
    */
    //SQL query using annotation
    @Select("SELECT * FROM person WHERE id = #{id}")
    public Person selectPerson(@Param("id") int id);
  
    /******************************************
    * Insert a person 
    * @param person
    * @return int
    */
    @Insert("INSERT INTO person (name) VALUES (#{name})")
    public int insertPerson(Person person);
}

For the method selectAllPerson() the SQL statement is going to be in the xml file.

Mapper.xml

( 4 ) Other .java & .sql files

Service.java: is just a helper java class wrapping Mapper.java methods.

package com.hmkcode.spring.mybatis.service;

import ...

public class Service {
  
  @Autowired 
  private Mapper mapper;
 
  public List selectAllPerson() {
  	return mapper.selectAllPerson();
  }
  public Person selectPerson(int id) {
  	return mapper.selectPerson(id);
  }
  public int insertPerson(Person person){
	return mapper.insertPerson(person);
  }
}

Person.java: is POJO plain java object to map data from/to it.

package com.hmkcode.spring.mybatis.vo;


public class Person 
{
  
  private int id;
  private String name;
  
 //getters & setters
}

App.java: runs the application, load spring-config.xml and perform some db operations.

package com.hmkcode.spring.mybatis;

import java.util.List;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.hmkcode.spring.mybatis.service.Service;
import com.hmkcode.spring.mybatis.vo.Person;


public class App 
{
  private static Log log = LogFactory.getLog(App.class);

    public static void main( String[] args )
    {

      ApplicationContext cxt = new ClassPathXmlApplicationContext("spring-config.xml");
      Service service = (Service) cxt.getBean("service");
  	
      log.info("Running App...");

        System.out.println("List persons = service.selectAllPerson()");
        List persons = service.selectAllPerson();
        System.out.println("-> "+persons+"\n");
                          
        System.out.println("Person person = service.selectPerson(2)");
        Person person = service.selectPerson(2);
        System.out.println("-> "+person+"\n");
                                                  
        System.out.println("service.insertPerson(person)");
        person.setName("Inserted person");
        service.insertPerson(person);
        System.out.println("-> inserted..."+"\n");
                                                                                
        System.out.println("List persons = service.selectAllPerson()");
        persons = service.selectAllPerson();
        System.out.println("-> "+persons+"\n");

    }
}

schema.sql & test-data.sql: used by H2 database to build data temporarily in the memory.

schema.sql
CREATE TABLE person (id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(255));

test-data.sql
INSERT INTO person (id,name) VALUES (1, 'person-1 name')
INSERT INTO person (id,name) VALUES (2, 'person-2 name')
INSERT INTO person (id,name) VALUES (3, 'person-3 name')
INSERT INTO person (id,name) VALUES (4, 'person-4 name')
INSERT INTO person (id,name) VALUES (5, 'person-5 name')
INSERT INTO person (id,name) VALUES (6, 'person-6 name')

Note: If you have Maven you can run this sample code directly using Maven command below.

../spring-mybatis>mvn exec:java

Source Code @ github

How to Run “Execute” Java Main Class Using Maven Command

hani.hmk — Tue, 30 Apr 2013 15:30:53 +0000

If you create a java project using Maven you can run it using Maven.

Objective:

How to run java main class using Maven?

Environment:

Maven

( 1 ) The Command

project_folder>mvn exec:java

( 2 ) pom.xml “needs to know about the main class“

As we can see from the command we did not mention the main class, so how Maven knows which class to run? The answer in the pom.xml.
We need to add some instruction to the pom.xml to be able to execute the main class.
We need to add the below xml segment to the pom.xml.

...

    
    	
      	maven-compiler-plugin
      	2.0.2
      	
        		1.6
        		1.6
      	
     
     	
      	org.codehaus.mojo
      	exec-maven-plugin
      	
             com.hmkcode.MainClassName
      	
     	
    
   
...

( 3 ) Example

If we have the following simple project with a main class “App.java”

“I have converted Maven project to Eclipse just to show the structure”

Now I will open the pom.xml file and add the above xml segment to the it.


  4.0.0

  com.hmkcode
  maven-run-main-class
  1.0-SNAPSHOT
  jar

  maven-run-main-class
  http://maven.apache.org

  
    UTF-8
  

  
    
      junit
      junit
      3.8.1
      test
    
  

  
    
    	
      	maven-compiler-plugin
      	2.0.2
      	
        		1.6
        		1.6
      	
     
     	
      	org.codehaus.mojo
      	exec-maven-plugin
      	
             com.hmkcode.App

Now, go to the project directory “maven-run-main-class” using the command prompt type the command:

..\maven-run-main-class>mvn exec:java

For more info about exec Maven plugin…