老外寫的文章真的很易懂！  
原文地址：http://www.mkyong.com/spring-mvc/spring-3-mvc-and-json-example/


Published: July 28, 2011 , Updated: July 27, 2011 , Author: mkyong

 

In Spring 3, you can enable “mvc:annotation-driven” to support object conversion to/from JSON format, if Jackson JSON processor is existed on the project classpath.

In this tutorial, we show you how to output JSON data from Spring MVC.

Technologies used :

Spring 3.0.5.RELEASE
Jackson 1.7.1
JDK 1.6
Eclipse 3.6
Maven 3
1. Project Dependencies

To use JSON in Spring MVC, you need to include Jackson dependency.

    <properties>
        <spring.version>3.0.5.RELEASE</spring.version>
    </properties>
 
    <dependencies>
 
        <!-- Jackson JSON Mapper -->
        <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-mapper-asl</artifactId>
            <version>1.7.1</version>
        </dependency>
 
        <!-- Spring 3 dependencies -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
 
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring.version}</version>
        </dependency>
 
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring.version}</version>
        </dependency>
 
    </dependencies>

 
2. Model

A simple POJO, later convert this object into JSON output.

package com.mkyong.common.model;
 
public class Shop {
 
    String name;
    String staffName[];
 
    //getter and setter methods
 
}

 
3. Controller

Add “@ResponseBody” in the return value, no much detail in the Spring documentation.

As i know, when Spring see

Jackson library existed on classpath
“mvc:annotation-driven” is enabled
Return method annotated with @ResponseBody
It will handle the JSON conversion automatically.

package com.mkyong.common.controller;
 
import org.springframework.stereotype.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 com.mkyong.common.model.Shop;
 
@Controller
@RequestMapping("/kfc/brands")
public class JSONController {
 
    @RequestMapping(value="{name}", method = RequestMethod.GET)
    public @ResponseBody Shop getShopInJSON(@PathVariable String name) {
 
        Shop shop = new Shop();
        shop.setName(name);
        shop.setStaffName(new String[]{"mkyong1", "mkyong2"});
 
        return shop;
 
    }
 
}
4. mvc:annotation-driven

Enable “mvc:annotation-driven” in your Spring configuration XML file.

<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-3.0.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-3.0.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">
 
    <context:component-scan base-package="com.mkyong.common.controller" />
 
    <mvc:annotation-driven />
 
</beans>
5. Demo

URL : http://localhost:8080/SpringMVC/rest/kfc/brands/kfc-kampar


Download Source Code

Download it – SpringMVC-JSON-Example.zip (7 KB)
References

mvc-annotation-driven documentation
High-performance JSON processor
Spring MVC and XML example