Spring mvc 用ajax传输json数据

在spring mvc3中，已经集成了Jackson(json处理器)来处理数据输出json格式,spring中封装的类是 org.springframework.http.converter.json.MappingJackson2HttpMessageConverter这个json转换器， 如果是springmvc3.2之前的版本,可以使用org.springframework.http.converter.MappingJacksonHttpMessageConverter这个json转换器。

Spring的详细介绍：这里

Json的详细介绍：这里

Spring mvc的详细介绍：这里

1.首先要添加maven的项目依赖，要在spring mvc中使用json的话，需要在项目中的pom.xml中包含Jackson的依赖项。

示例：

 <dependencies>

<dependency>
      <groupId>com.fasterxml</groupId>
      <artifactId>jackson-annotations</artifactId>
      <version>2.1.1</version>
  </dependency>
  <dependency>
      <groupId>com.fasterxml</groupId>
      <artifactId>jackson-core</artifactId>
      <version>2.1.1</version>
  </dependency>
  <dependency>
      <groupId>com.fasterxml</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.1.1</version>
  </dependency>

      <!-- Spring 3 dependencies -->
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aop</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aspects</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-beans</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context-support</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-expression</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-instrument</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-instrument-tomcat</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jms</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-orm</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-oxm</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>
  <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>3.2.0.RELEASE</version>
  </dependency>

  </dependencies>

2.建立一个POJO类，就以User类为例，这里就贴User类的代码了，大家都懂。

3.通过@Controller注解建立控制器

加上@ResponseBody

代码如下所示:

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import com.Student;
@Controller
public class TestJsonController {

     @RequestMapping(value="/finddata", method = RequestMethod.GET)
     public @ResponseBody Student getJSONData() {

         Student result = new Student();
         result.setUserName("360sdn.com");
         result.setArray(new String[]{"360sdn1", "360sdn2"});

         return result;

     }
}

4.配置Spring的servlet配置文件来配置json的输出转换器，但是在我的实际实践中发现不用配置Xml中的bean也能将数据转换为json格式的。

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd
        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">
   <!-- 启动spring mvc的注解功能，完成请求和注解POJO的映射 -->
   <!--  配置信息转换，将用@responsebody注解的返回值转换为json返回前台，
       编码为utf-8-->
    <bean
      class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
        <property name="messageConverters">
            <list>
                <bean
                    class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
                    <property name="supportedMediaTypes">
                        <list>
                            <value>application/json;charset=UTF-8</value>
                        </list>
                    </property>
                </bean>
            </list>
        </property>
    </bean>
    <mvc:annotation-driven/>
</beans>

然后运行应该就能看到json格式的数据了。