缺少jar包

  <!--springmvc 4.x Jackson Json处理工具包 -->  
        <dependency>  
            <groupId>com.fasterxml.jackson.core</groupId>  
            <artifactId>jackson-databind</artifactId>  
            <version>${jackson.version}</version>  
        </dependency>  
  
    <!-- springmvc 3.x Jackson Json处理工具包 -->  
    <!-- <dependency>  
        <groupId>org.codehaus.jackson</groupId>  
        <artifactId>jackson-core-asl</artifactId>  
        <version>1.9.13</version>  
    </dependency>  
    <dependency>  
        <groupId>org.codehaus.jackson</groupId>  
        <artifactId>jackson-mapper-asl</artifactId>  
        <version>1.9.13</version>  
    </dependency> --> 

@RequestMapping设置错误 如

@RequestMapping(value = "/xx/xx", produces = "text/html;charset=UTF-8")

@RequestMapping(value = "/xx/xx", produces = "text/plain;charset=UTF-8")

应设置成

@RequestMapping(value = "/xx/xxx", produces = "application/json;charset=UTF-8")