Spring MVC No converter found for return value of type 解决方法

1、在pom中添加 jackson

  <properties>
     <jackson.version>2.8.5</jackson.version>
 </properties>

 <!-- jackson -->
     <dependency>
         <groupId>com.fasterxml.jackson.core</groupId>
         <artifactId>jackson-core</artifactId>
         <version>${jackson.version}</version>
     </dependency>
     <dependency>
         <groupId>com.fasterxml.jackson.core</groupId>
         <artifactId>jackson-databind</artifactId>
         <version>${jackson.version}</version>
     </dependency>
     <dependency>
         <groupId>com.fasterxml.jackson.core</groupId>
         <artifactId>jackson-annotations</artifactId>
         <version>${jackson.version}</version>
     </dependency>

2、在 spring的配置文件中配置

 <mvc:annotation-driven >
         <mvc:message-converters>
             <bean class="org.springframework.http.converter.StringHttpMessageConverter"/>
             <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"/>
         </mvc:message-converters>
     </mvc:annotation-driven>

3、在controller上加@ResponseBody 标签