Spring REST Web Service and Content Negotiation

com.spring.restful.controller.WebConfig.java

This customized class should be in the same package in which our controller exists because we are using <context:component-scan base-package="com.spring.restful" /> to scan the controller package.

We need to override the configureContentNegotiation method of the WebMvcConfigurerAdapter for content negotiations.

package com.spring.restful.controller;

import org.springframework.context.annotation.Configuration;

import org.springframework.http.MediaType;

import org.springframework.web.servlet.config.annotation.ContentNegotiationConfigurer;

import org.springframework.web.servlet.config.annotation.EnableWebMvc;

import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration

@EnableWebMvc

public class WebConfig extends WebMvcConfigurerAdapter {

      /** Total customization. */

      @Override

      public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {

            configurer.favorPathExtension(false).

            favorParameter(true).

            parameterName("mediaType").

            ignoreAcceptHeader(true).

            useJaf(false).

            defaultContentType(MediaType.APPLICATION_JSON).

            mediaType("xml", MediaType.APPLICATION_XML).

            mediaType("json", MediaType.APPLICATION_JSON);

      }

}

web.xml

<?xml version="1.0" encoding="UTF-8"?>

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

      xmlns="http://java.sun.com/xml/ns/javaee"

      xmlns:web="http://java.sun.com/xml/ns/javaee"

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

      http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"

      id="WebApp_ID" version="2.5">

      <display-name>SpringRestFulService</display-name>

      <welcome-file-list>

            <welcome-file>index.html</welcome-file>

            <welcome-file>index.htm</welcome-file>

            <welcome-file>index.jsp</welcome-file>

            <welcome-file>default.html</welcome-file>

            <welcome-file>default.htm</welcome-file>

            <welcome-file>default.jsp</welcome-file>

      </welcome-file-list>

      <servlet>

            <servlet-name>rest</servlet-name>

            <servlet-class>

                  org.springframework.web.servlet.DispatcherServlet

            </servlet-class>

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

      </servlet>

      <servlet-mapping>

            <servlet-name>rest</servlet-name>

            <url-pattern>/*</url-pattern>

      </servlet-mapping>

</web-app>

rest-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>

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

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

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

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

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

      xsi:schemaLocation="http://www.springframework.org/schema/mvc

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

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

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

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

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

        http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">

      <!-- Enables the Spring MVC @Controller programming model -->

      <annotation-driven />

      <!-- for processing requests with annotated controller methods and set Message Convertors from the list of convertors -->

      <beans:bean

      class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">

            <beans:property name="messageConverters">

                  <beans:list>

                        <beans:ref bean="jsonMessageConverter" />

                  </beans:list>

            </beans:property>

      </beans:bean>

      <!-- To convert JSON to Object and vice versa -->

      <beans:bean id="jsonMessageConverter"

      class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">

      </beans:bean>

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

</beans:beans>

com.spring.restful.controller.UserDetailsService.java

package com.spring.restful.controller;

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.bind.annotation.RestController;

import com.spring.restful.dao.UserDAO1;

import com.spring.restful.model.UsersDTO;

@RestController

public class UserDetailsService {

      @RequestMapping(value="/user/{msisdn}",

                  method = RequestMethod.GET,

                  produces={"application/xml", "application/json"})

      public @ResponseBody UsersDTO

                  getUserInformation( @PathVariable(value="msisdn")  String msisdn) {

           

            UsersDTO dto = UserDAO1.getUserDetail(msisdn);

            return dto;

      }

}

com.spring.restful.dao.UserDAO1.java

package com.spring.restful.dao;

import java.util.Date;

import com.spring.restful.model.UsersDTO;

public class UserDAO1 {

      public static UsersDTO getUserDetail(String msisdn) {

            /* we can fetch the user information from DB. */

            UsersDTO users = new UsersDTO();

            users.setUserId("123");

            users.setUserName("Rajesh");

            users.setDob(new Date());

            users.setMsisdn(msisdn);

            return users;

      }

}

com.spring.restful.dao.UsersDTO.java

package com.spring.restful.model;

import java.util.*;

import javax.xml.bind.annotation.XmlElement;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement

public class UsersDTO {

      private String userId;

      private String userName;

      private Date dob;

      private String msisdn;

     

      @XmlElement

      public String getUserId() {

            return userId;

      }

      public void setUserId(String userId) {

            this.userId = userId;

      }

     

      @XmlElement

      public String getUserName() {

            return userName;

      }

      public void setUserName(String userName) {

            this.userName = userName;

      }

     

      @XmlElement

      public String getMsisdn() {

            return msisdn;

      }

      public void setMsisdn(String msisdn) {

            this.msisdn = msisdn;

      }

     

      @XmlElement

      public Date getDob() {

            return dob;

      }

      public void setDob(Date dob) {

            this.dob = dob;

      }

}

Note:
For XML binding, we need to put annotation on the DTO class fields.
For json response, we need to put the jackson-mapper  jars in class path only.

Sample Request to fetch the data:

http://localhost:8085/RestServiceUsingSpring/user.json/770000156/?mediaType=json

http://localhost:8085/RestServiceUsingSpring/user.json/770000156/?mediaType=xml

Jar needed:

Spring core jar

Spring web jar

commons-logging-1.1.1.jar

jackson-annotations-2.5.4.jar

jackson-core-2.2.0.jar

jackson-databind-2.1.4.jar

jaxb-api-2.2.jar for XML binding

jstl-1.2.jar

spring-beans-4.0.0.RELEASE.jar

spring-context-4.0.0.RELEASE.jar

spring-core-4.0.0.RELEASE.jar

spring-expression-4.0.0.RELEASE.jar

spring-web-4.0.0.RELEASE.jar

spring-webmvc-4.0.0.RELEASE.jar.