Content type 'application/json;charset=UTF-8' not supported異常的解決過程

首先說一下當時的場景，其實就是一個很簡單的添加操作，后台傳遞的值是json格式的，如下圖

 

 ，后台對應的實體類，

@Data
@EqualsAndHashCode(callSuper = false)
public class Route implements Serializable {

    private static final long serialVersionUID = 1L;

    /**
     * id
     */
    private String id;

    /**
     * 設備id
     */
    private String deviceId;

    /**
     * 路由地址
     */
    private String destNetwork;

    /**
     * 下一跳
     */
    private String nextHop;

    /**
     * 路由所屬zone
     */
    private String zone;

    /**
     * 0：系統解析；1：明細路由；2：假路由
     */
    private String isReload;

    /**
     * nat路由
     */
    private String isNatDummyRoute;

    private String createTime;

    /**
     * 是否禁用，主要適用於系統解析路由
     */
    private String isDisabled;

    @TableField(exist = false)
    private Device device;

    /**
     * 路由轉化后的對象
     */
    @TableField(exist = false)
    private IpAddr ipAddr;
}

后台對應的Controller中的代碼

@RequestMapping(value = "add",method = RequestMethod.POST)
    public R add(@RequestBody Route route){

            String deviceIp = route.getDeviceId();
            Device device = deviceService.getByIp(deviceIp);
            Date date = new Date();
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            String dateStr = sdf.format(date);
            route.setDeviceId(device.getId());
            route.setIsDisabled("0");
            route.setCreateTime(dateStr);
            routeService.save(route);
        return R.success();
    }

，看代碼可知，頁面傳遞到后台的值應該能直接轉成實體類Route對應的字段。但是並沒有，報錯信息是如下：

2020/09/28-10:52:00 WARN [http-nio-8999-exec-6] MappingJackson2HttpMessageConverter - Failed to evaluate Jackson deserialization for type [[simple type, class com.interact.firewall.base.biz.entity.Route]]: com.fasterxml.jackson.databind.JsonMappingException: Conflicting setter definitions for property "parent": com.interact.firewall.core.bean.service.Service#setParent(1 params) vs com.interact.firewall.core.bean.service.Service#setParent(1 params)
2020/09/28-10:52:00 WARN [http-nio-8999-exec-6] MappingJackson2HttpMessageConverter - Failed to evaluate Jackson deserialization for type [[simple type, class com.interact.firewall.base.biz.entity.Route]]: com.fasterxml.jackson.databind.JsonMappingException: Conflicting setter definitions for property "parent": com.interact.firewall.core.bean.service.Service#setParent(1 params) vs com.interact.firewall.core.bean.service.Service#setParent(1 params)
2020/09/28-10:52:00 ERROR [http-nio-8999-exec-6] GlobalExceptionHandler - 捕獲到Exception異常
org.springframework.web.HttpMediaTypeNotSupportedException: Content type 'application/json;charset=UTF-8' not supported
    at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodArgumentResolver.readWithMessageConverters(AbstractMessageConverterMethodArgumentResolver.java:225)
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.readWithMessageConverters(RequestResponseBodyMethodProcessor.java:158)
    at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.resolveArgument(RequestResponseBodyMethodProcessor.java:131)
    at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:121)
    at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:167)
    at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134)
    at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:878)
    at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:792)
    at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:909)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:652)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:733)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
    at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:373)
    at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
    at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:868)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1589)
    at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)

於是我就按照這個異常信息去排查，

有人說是缺少依賴。但是並沒有解決

 

 

有人說是字段沒有映射對，就是說頁面傳遞到后台的值跟實體類對應不上，但是我反復比對沒有問題。

之前實體類中還寫了一部分處理數據的方法，我也進行刪除進行測試還是不行。

后來請教同事，同事也懷疑是實體類的問題，於是重新建了一個實體類，只要數據庫的字段，不是數據庫中的字段進行刪除，結果可以了，於是繼續排查，確認到底是哪個地方引起的，最終確認了，是因為實體類中引用了一個對象。將引用的這個對象刪掉就沒問題了，但是我們想了一下，其他的實體類也有因為需要關聯查詢直接引其他對象的，但是卻沒有出問題。為什么單單這個出問題呢。

其實報錯中已經有提示了，在異常信息上邊有兩行警告代碼：

Failed to evaluate Jackson deserialization for type [[simple type, class com.interact.firewall.base.biz.entity.Route]]: com.fasterxml.jackson.databind.JsonMappingException: Conflicting setter definitions for property "parent": com.interact.firewall.core.bean.service.Service#setParent(1 params) vs com.interact.firewall.core.bean.service.Service#setParent(1 params)

說的其實是序列化相關的問題，后來我們查看了一下在Route中引用的對象，確實，並沒有實現Serializable 這個接口，導致這個問題的發生，但是這個對象又必須引用，那怎么辦呢？想了一下，是不是有個注解能夠忽略反序列化字段呢？於是查了一下，果然有

JsonIgnore這個注解就可以將被標記屬性忽略反序列化功能。

總結一下：其實這個問題的根本原因就是實體類中引用了一個沒有實現實現Serializable 接口的對象，無法被反序列化，只需要在這個對象上添加@JsonIgnore這個注解即可。對了 一直在說沒有實現Serializable接口的對象是實體類中最后一個Ipaddr那個對象。

/**
     * 路由轉化后的對象
     */
    @TableField(exist = false)
    @JsonIgnore
    private IpAddr ipAddr;