默认情况下，springMVC的@ResponseBody返回的是String类型，如果返回其他类型则会报错。

使用fastjson的情况下，在springmvc.xml配置里加入：

<mvc:annotation-driven>

<mvc:message-converters

register-defaults="true">

<bean

class="com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter">

<property name="supportedMediaTypes">

<list>

<value>text/html;charset=UTF-8</value>

<value>application/json</value>

<value>application/xml;charset=UTF-8</value>

</list>

</property>

</bean>

</mvc:message-converters>

</mvc:annotation-driven>

在pom.xml引入依赖：

<dependency>

          <groupId>com.alibaba</groupId>

          <artifactId>fastjson</artifactId>

          <version>1.2.47</version>

</dependency>

<dependency>

          <groupId>com.fasterxml.jackson.core</groupId>

          <artifactId>jackson-core</artifactId>

          <version>2.7.3</version>

</dependency>

<dependency>

          <groupId>com.fasterxml.jackson.core</groupId>

          <artifactId>jackson-databind</artifactId>

          <version>2.7.3</version>

</dependency>