1.添加jackson的jar包
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>${jackson1.version}</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>${jackson1.version}</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
<version>${jackson1.version}</version>
</dependency>
已经添加 无效
2.在配置文件中添加
<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>
无效
最后的解决方法是修改jackson的版本号
spring是4.3.6 jackson使用2.8.1无效 使用2.7.3是有效的