Spring 3 Rest Web Service Integration

                   Spring 3 Rest Web Service Integration

Hi  Readers,

      

       This is my third post. I am going to start how to build  Restful Web Service using Spring 3.1 MVC.

We can use the existing Spring MVC request mapping and the help of JAX-RS 2.0 implementation for JSON and XML marshaling/demarshaling.

JAVA Configuration

We need to change the environmental system variable JAVA_HOME to C:\Java\jdk1.6.

For Ubutnu user install Java apt-get install openjdk-7-jdk

set Java using JAVA_HOME =/usr/lib/jvm/java-7-sun

JBoss 7 Installation

We can download JBoss 7 from below JBoss site 

http://www.jboss.org/jbossas/downloads/

Download the Zip file.

SET JBOSS_HOME=C:\jboss-as-7.1.1.Final

C:\jboss-as-7.1.1.Final\bin>service.bat install

For Ubutnu users download JBoss 7 using below command

wget http://download.jboss.org/jbossas/7.1/jboss-as-7.1.1.Final/jboss-as-7.1.1.Final.tar.gz

Finally unzip JBoss 7 and put in folder /usr/local/share/JBoss 

tar xfvz jboss-as-7.1.1.Final.tar.gz

mv jboss-as-7.1.1.Final /usr/local/share/jboss


MySql Installation

We need to download MySql from the below site


http://dev.mysql.com/downloads/mysql

We can install MySql for  Ubutnu users using below command


sudo apt-get install mysql-server

We can create database new database using below command

mysqladmin create <databasename>

Dumping Tables in MySql Database from DB Scripts

First we need to create the database in MySql DB.
eate Create database MyDB;

We can dump the tables in MySql databse from the DB Script using below command

mysql>use SatyaDB;
mysql>Source /usr/local/share/DB_Dump_file.sql;

We will get all the tables from the dump file into my newly created database.

Spring MVC Context Configuration

This is the entry point to the server. Contains all the configuration and initialization etc...

We need to enable the annotation driven configuration.The base package we need to scan is com.satya.

<mvc:annotation-driven>

<context:component-scan base-package="com.satya"/>

spring-servlet.xml

<beans xmlns="http://www.springframework.org/schema/beans"

  xmlns:context="http://www.springframework.org/schema/context"

  xmlns:mvc="http://www.springframework.org/schema/mvc" 

  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

  xsi:schemaLocation="

        http://www.springframework.org/schema/beans     

        http://www.springframework.org/schema/beans/spring-beans-3.1.xsd

        http://www.springframework.org/schema/context 

        http://www.springframework.org/schema/context/spring-context-3.1.xsd

        http://www.springframework.org/schema/mvc

        http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd">

  <mvc:annotation-driven />

  <context:component-scan base-package="com.satya" />

</beans>

Spring Integration Web Container

org.springframework.web.servlet.DispatcherServlet is the front controller.

The web.xml file will be kept WebContent/WEB-INF directory of your web application.Upon initialization of  spring DispatcherServlet, the framework will try to load the application context from a file named [servlet-name]-servlet.xml located in the application's WebContent/WEB-INF directory. In this case our file will be spring-servlet.xml.

web.xml 

<web-app id="WebApp_ID" version="2.4"

  xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

  xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 

  http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

  <display-name>Spring MVC REST</display-name>

  <servlet>

    <servlet-name>spring</servlet-name>

    <servlet-class>

                    org.springframework.web.servlet.DispatcherServlet

                </servlet-class>

    <load-on-startup>1</load-on-startup>

  </servlet>

  <servlet-mapping>

    <servlet-name>spring</servlet-name>

    <url-pattern>/rest</url-pattern>

  </servlet-mapping>

</web-app> 

If we don't want to go with default file name as [servlet-name]-servlet.xml and default location as WebContent/WEB-INF. We can customize the file name and location by adding the servlet listener.. 

We need to add ServletLoaderListener in the web.xml file.

web.xml

<web-app...>

<!-------- DispatcherServlet definition goes here----->
....
<context-param>
   <param-name>contextConfigLocation</param-name>
   <param-value>/WEB-INF/HelloWeb-servlet.xml</param-value>
</context-param>

<listener>
   <listener-class>
      org.springframework.web.context.ContextLoaderListener
   </listener-class>
</listener>

</web-app>

Service/Controller

We need to write the web service in our Spring MVC controller. Base on our requirement, scale and scope each module contains one or more controller.

@Controller

@RequestMapping(value="/module")

public class SampleController{   }

Controller might holds the request url path. Here the request url path is "/module"

Controller holds the method and rest url path.

@Autowired
ServiceManager serviceManager;

@RequestMapping(value = "/path" method = RequestMethod.POST)

public ModelAndView getdata(@Valid @RequestBody SampleRequest request,BindingResult result){

                     if(result.hasErrors()){

                                                       

                                                       }

          SampleResponse  sampleResponse = serviceManager.getdata(request);

          return new ModelAndView("SampleResponse","sampleResponse", sampleResponse);

    }

ServiceManager

Calls the DAO methods and holds the business logic.

DataAccessObject

We need to initialize jdbc template in the DAO file.

@Autowired

public void setDataSource(DataSource dataSource) {

     

      this.jdbcTemplateObject = new JdbcTemplate(dataSource);

   }

Here datasource is initialize the datasource from the dispatcher servlet.

We can change the datasource later if required if required. We can also specify more than one datasource.

<!-- Initialization for data source -->

   <bean id="dataSource" 

      class="org.springframework.jdbc.datasource.DriverManagerDataSource">

      <property name="driverClassName" value="com.mysql.jdbc.Driver"/>

      <property name="url" value="jdbc:mysql://localhost:3306/TEST"/>

      <property name="username" value="root"/>

      <property name="password" value="password"/>

   </bean>

We need to implement the DAO method for generating response.

public SampleResponse getdata(SampleRequest request){

            String sql="select stdId,stdName from student where stdId=:stdId";

            SqlParameterSource  source=new BeanPropertySqlParameterSource(request);

             BeanPropertyRowMapper<SampleResponse> rowmapper=new BeanPropertyRowMapper(SampleResponse.class);

              SampleResponse response=this.jdbcTemplate.queryForObject(sql, source, rowmapper);

              return response;

            }

Finally the Response POJO will be sent to the Dispatcher Servlet.

SampleRequest

This class is used for marshaling.

 package com.satya.model; 

import javax.xml.bind.annotation.XmlRootElement; 

@XmlRootElement 

public class SampleRequest

    { 

            String stdName;
   

            public int getstdName() { return stdName; } 
            public void setstdName(int stdName) { this.stdName = stdName; }       

     }

SampleResponse

This class is used  for unmarshalling.

package com.satya.model; 

import javax.xml.bind.annotation.XmlRootElement; 

@XmlRootElement 

public class SampleResponse

    { 

            int stdId;

            String stdRegNo;
            String stdName;
            String stdEmailAddress;
             int stdMobileNo;
      

            public int getstdId() { return stdId; } 

            public void setstdId(int id) { this.stdId = stdId; }
            public int getstdRegNo() { return stdRegNo; } 
            public void setstdRegNo(int stdRegNo) { this.stdRegNo = stdRegNo; }   
            public int getstdName() { return stdName; } 
            public void setstdName(int stdName) { this.stdName = stdName; }   
            public int getstdEmailAddress() { return stdEmailAddress; } 

            public void setstdEmailAddress(int stdEmailAddress) {                  this.stdEmailAddress = stdEmailAddress; }    

     }

Response Preparation

<bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">

 <property name="order" value="1" />

 <property name="mediaTypes">

<map>

  <entry key="json" value="application/json" />

  <entry key="xml" value="application/xml" />

  <entry key="rss" value="application/rss+xml" />

</map>

 </property>

 <property name="defaultViews">

<list>

 <!-- JSON View -->

 <bean

class="org.springframework.web.servlet.view.json.MappingJacksonJsonView">

 </bean>

 <!-- RSS View -->

 <bean class="com.mkyong.common.rss.RssFeedView" />

 <!-- JAXB XML View -->

 <bean class="org.springframework.web.servlet.view.xml.MarshallingView">

<constructor-arg>

<bean class="org.springframework.oxm.jaxb.Jaxb2Marshaller">

  <property name="classesToBeBound">

<list>

  <value>com.satya</value>

</list>

  </property>

</bean>

</constructor-arg>

 </bean>

</list>

 </property>

 <property name="ignoreAcceptHeader" value="true" />

</bean>

<!-- If no extension matched, use JSP view -->

<bean

class="org.springframework.web.servlet.view.InternalResourceViewResolver">

<property name="order" value="2" />

<property name="prefix">

<value>/WEB-INF/pages/</value>

</property>

<property name="suffix">

<value>.jsp</value>

</property>

</bean>

</beans>

Rest URL

http://localhost:8080/rest/module/path