how to make rest service in spring mvc?

Question

I am trying to make simple rest service which is used by everybody example it will consume by mobile developer.so I need to send static data to every one .I am trying to send static this data .

{
name:"abcd"
} 

in other word if some one hit my system like this http://192.168.12.61:8080/springfirst/hello .then user get above json.

I follow this like to make http://www.programming-free.com/2014/03/spring-mvc-40-restful-web-service-json.html

I follow this step

• download these jar files(-- jackson-annotations-x.x.x.jar -- jackson-core-x.x.x.jar -- jackson-databind-x.x.x.jar) and include in lib folder.

here is my code 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 Application</display-name>

   <servlet>
      <servlet-name>HelloWeb</servlet-name>
      <servlet-class>
         org.springframework.web.servlet.DispatcherServlet
      </servlet-class>
   </servlet>

   <servlet-mapping>
      <servlet-name>HelloWeb</servlet-name>
      <url-pattern>/</url-pattern>
   </servlet-mapping>

</web-app>

hello-servelts.xml

<beans xmlns="http://www.springframework.org/schema/beans"
   xmlns:context="http://www.springframework.org/schema/context"
   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-3.0.xsd

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

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

   <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
      <property name="prefix" value="/WEB-INF/jsp/" />
      <property name="suffix" value=".jsp" />
   </bean>

</beans>

controller.js

package com.tutorialspoint;

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
@RequestMapping("/hello")
public class HelloController{

    @RequestMapping( method = RequestMethod.GET,headers="Accept=application/json")
   public String printHello(ModelMap model) {

      return "abcd";
   }

}

Answer 1

you have configuration problems:

• If you register DispatcherServlet in web.xml with out context configuration file path, then you should name the context file as per your servletName-servlet.xml.

So rename hello-servelts.xml as HelloWeb-servlet.xml.

and add @ResponseBody in your controller handler method to return JSON like:

 @RequestMapping( method = RequestMethod.GET,headers="Accept=application/json")
 public @ResponseBody Map printHello(ModelMap model) {
     Map<String,String> json = new HashMap<String,String>();
     json.put("name", "abcd");
      return json;
 }

Here is the working application using ContentNegotiatingViewResolver.

how to make rest service in spring mvc?

Ans, there is different ways are available. I am listing below some of:

• To read/write JSON data from HTTP request or response you should use @RequestBody to read from HTTP request and @ResponseBody to write a object as JSON into HTTP response.
• Spring provides ContentNegotiatingViewResolver where you can use it to resolve Views by request URL extension OR request ACCEPT header value. for example if URL is /view.html then it will return a view which has text/html content-type. same you can configure it to return JSON as well.

ContentNegotiatingViewResolver configuration for JSON View will look like:

<bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
      <property name="order" value="1" />
      <property name="mediaTypes">
        <map>          
           <entry key="json" value="application/json" />           
        </map>
      </property>

      <property name="defaultViews">
        <list>
          <!-- JSON View -->
          <bean class="org.springframework.web.servlet.view.json.MappingJackson2JsonView">                      
          </bean>
         </list>
      </property>
      <property name="ignoreAcceptHeader" value="true" />
    </bean>

Note: Jackson mapper or any other mapper should be available on buildpath in order to work JSON serialize and deserialize.

If you use Maven, then confirm this dependency available in pom.xml:

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.4.3</version>
</dependency>

SEE ALSO:

• How to return object from controller to ajax in spring-mvc
• New features in spring mvc 3.1

Answer 2

You can follow this guide which is an official documentation and it is using spring-boot which will do easy your way to start writing services.

You rest service would be something like

@RestController
@RequestMapping("/hello")
public class HelloController{

@RequestMapping( method = RequestMethod.GET,headers="Accept=application/json")
@ResponseBody
public String printHello() {

  return "abcd";
}

}