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spring boot 返回json数据错误

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悬赏园豆：100 [已解决问题] 解决于 2018-03-03 10:06

POJO

package com.example.project01.domain;

import java.io.Serializable;

public class User implements Serializable{

    private static final long serialVersionUID = 1L;
    private Integer id;
    private String name;
    private Integer age;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

}

 

controller

package com.example.project01.controller;


import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.example.project01.domain.User;
import com.example.project01.domain.UserMapper;

@RestController
public class HelloController {
    @Autowired
    private UserMapper userMapper;
    
    
    @RequestMapping("getUser")
    public  User getUser() {
        User user = userMapper.findByName("BBB");
        return user;
    }
}

 

mapper

package com.example.project01.domain;


import org.apache.ibatis.annotations.*;

@Mapper
public interface UserMapper {

    @Results({
        @Result(property = "name", column = "name"),
        @Result(property = "age", column = "age")
    })
    @Select("SELECT * FROM USER WHERE NAME = #{name}")
    User findByName(@Param("name") String name);
    
    

}

 

错误

java.lang.IllegalArgumentException: No converter found for return value of type: class com.example.project01.domain.User
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:187) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.handleReturnValue(RequestResponseBodyMethodProcessor.java:174) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.springframework.web.method.support.HandlerMethodReturnValueHandlerComposite.handleReturnValue(HandlerMethodReturnValueHandlerComposite.java:81) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:113) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) ~[spring-webmvc-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) ~[tomcat-embed-websocket-8.5.27.jar:8.5.27]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:108) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) ~[spring-web-4.3.14.RELEASE.jar:4.3.14.RELEASE]
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:199) ~[tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) [tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:504) [tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) [tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:81) [tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) [tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:342) [tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:803) [tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) [tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:790) [tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1459) [tomcat-embed-core-8.5.27.jar:8.5.27]
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-8.5.27.jar:8.5.27]
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [na:1.8.0_121]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [na:1.8.0_121]
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-8.5.27.jar:8.5.27]
    at java.lang.Thread.run(Thread.java:745) [na:1.8.0_121]
wdmiye的主页 wdmiye | 初学一级 | 园豆：118
提问于：2018-03-01 16:22
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最佳答案
1

我用的spring boot v1.5.10.RELEASE 默认json数据转换依赖jackson2.81版本,运行maven clien 再运行maven install 报警告 本地仓库找不到Jackson2.8.1的jar包,重新下载jacksonjar包或者引入fastjson依赖即可 

wdmiye | 初学一级 |园豆：118 | 2018-03-03 10:04
其他回答(3)
0 
package com.example.project01.domain;


import org.apache.ibatis.annotations.*;

@Mapper
public interface UserMapper {

    @Results({
        @Result(property = "name", column = "name"),
        @Result(property = "age", column = "age")
    })
    @Select("SELECT name,age FROM USER WHERE NAME = #{name}")
    Map<String,Integer> findByName(@Param("name") String name);
}

或者：

package com.example.project01.domain;


import org.apache.ibatis.annotations.*;

public interface UserMapper {

    @Select("SELECT * FROM USER WHERE NAME = #{name}")
    public User findByName(@Param("name") String name);
 
}


 


 


                        


                        

                            


    

            

                收获园豆：40
            

    

    

        悟行
        |
        园豆：12559
        (专家六级)
        |
        2018-03-01 16:51

    




                        


                        




    


还是一样的错误,这个跟你讲的应该没有关系,我断点看是可以返回一个正常的实体的




 

    

    

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        wdmiye
        |
        园豆：118
        (初学一级)
        |
        2018-03-01 17:17
    








                        


                        
                    

                

                

                    

                        
                        0
                        
                    

                    

                        




@RequestMapping("getUser")
@ResponseBody
    public  User getUser() {
        User user = userMapper.findByName("BBB");
        return user;
    }




加入@ResponseBody试下
                        


                        

                            


    

            

                收获园豆：30
            

    

    

        小苗巴
        |
        园豆：232
        (菜鸟二级)
        |
        2018-03-01 21:27

    




                        


                        




    


已经有@RestController注解了

    

    

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        wdmiye
        |
        园豆：118
        (初学一级)
        |
        2018-03-02 08:42
    








                        


                        
                    

                

                

                    

                        
                        0
                        
                    

                    

                        


Integer 写成int

                        


                        

                            


    

            

                收获园豆：30
            

    

    

        pkyou
        |
        园豆：98
        (初学一级)
        |
        2018-03-02 14:21

    




                        


                        

                        


                        
                    

                

        







    
    




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