2.原因:
Spring4.0后jackson依赖包不一样导致
3.解决方案
Spring 4.x.x版本后使用org.springframework.http.converter.json.MappingJackson2HttpMessageConverter所对应的jar
在maven配置jackson依赖包
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.8.5</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.8.5</version>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
<version>2.8.5</version>
</dependency>