springmvc 4 返回json数据

1.导入相关jar包

<dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>javax.servlet-api</artifactId>
			<version>3.1.0</version>
			<scope>provided</scope>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
			<version>4.1.5.RELEASE</version>
		</dependency>
		<dependency>
			<groupId>com.fasterxml.jackson.core</groupId>
			<artifactId>jackson-core</artifactId>
			<version>2.5.4</version>
		</dependency>
		<dependency>
			<groupId>com.fasterxml.jackson.core</groupId>
			<artifactId>jackson-databind</artifactId>
			<version>2.5.4</version>
		</dependency>
		<dependency>
			<groupId>com.fasterxml.jackson.core</groupId>
			<artifactId>jackson-annotations</artifactId>
			<version>2.5.4</version>
		</dependency>

2.配置servlet.xml文件

<mvc:annotation-driven /> <!-- mvc驱动 -->
	<context:component-scan base-package="com" /> <!-- 扫描的包 -->

	 <bean id="stringConverter"  
        class="org.springframework.http.converter.StringHttpMessageConverter">  
        <property name="supportedMediaTypes">  
            <list>  
                <value>text/plain;charset=UTF-8</value>  字符串编码
            </list>  
        </property>  
    </bean>  
    <bean id="jsonConverter"  
        class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"></bean>  
    <bean  
        class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">  
        <property name="messageConverters">  
            <list>  
                <ref bean="stringConverter" />  
                <ref bean="jsonConverter" />  
            </list>  
        </property>  
    </bean>  

3.在函数方法上添加@ ResponseBody注解

@RequestMapping("/getjson")
	@ResponseBody
	public Object getJson() {
		UserInfo user = new UserInfo();
		user.setAge(12);
		user.setName("sss");
		user.setSex(1);
		BaseJson baseJson = new BaseJson();
		baseJson.setCode("1");
		baseJson.setMsg("哈哈哈哈哈哈");
		baseJson.setData(user);
		return baseJson;
	}