@RequestBody对象为空，异常Required request body is missing错误解决

1.异常

org.springframework.http.converter.HttpMessageNotReadableException: Required request body is missing

情况一、

2.问题展示

@RequestMapping(value = "/somewhere", method = POST)
public SomeResponse someHandler(@RequestBody XXXDTO xxxDTO) { ... }
 
当入参DTO对象为空时，

@RequestBody对应http请求body,当请求body为空时，异常！
org.springframework.http.converter.HttpMessageNotReadableException: Required request body is missing: public com.rpc.common.Result<com.rpc.common.dto.PageDto<com.order.dto.OrderListDTO>> com.gateway.controller.OrderController.listOrder(com.*.*.order.dto.ListOrderPageDTO)
        at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.readWithMessageConverters(RequestResponseBodyMethodProcessor.java:154)
        at org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor.resolveArgument(RequestResponseBodyMethodProcessor.java:128)
        at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:121)
        at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:158)
        at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:128)
        at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:97)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
        at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:967)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
        at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
        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:52)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
        at org.springframework.boot.web.filter.ApplicationContextHeaderFilter.doFilterInternal(ApplicationContextHeaderFilter.java:55)

        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)

@Override
    protected <T> Object readWithMessageConverters(NativeWebRequest webRequest, MethodParameter parameter,
            Type paramType) throws IOException, HttpMediaTypeNotSupportedException, HttpMessageNotReadableException {

        HttpServletRequest servletRequest = webRequest.getNativeRequest(HttpServletRequest.class);
        ServletServerHttpRequest inputMessage = new ServletServerHttpRequest(servletRequest);

        Object arg = readWithMessageConverters(inputMessage, parameter, paramType);
        if (arg == null) {
            if (checkRequired(parameter)) {
                throw new HttpMessageNotReadableException("Required request body is missing: " +
                        parameter.getMethod().toGenericString());
            }
        }
        return arg;
    }

    protected boolean checkRequired(MethodParameter parameter) {
        return (parameter.getParameterAnnotation(RequestBody.class).required() && !parameter.isOptional());
    }

看上图，最终是RequestBody注解的required属性。!parameter.isOptional()代表是否支持null,如果参数类型支持null,则是false,最终不用校验required.

public @interface RequestBody {

    /**
     * Whether body content is required.
     * <p>Default is {@code true}, leading to an exception thrown in case
     * there is no body content. Switch this to {@code false} if you prefer
     * {@code null} to be passed when the body content is {@code null}.
     * @since 3.2
     */
    boolean required() default true;

}

看上图，默认是true.我们只需要@RequestBody （required=false）

3.解决办法

1）@RequestBody （required=false）

 

2) 不要让DTO对象为空

情况二、

springMvc的新注解：GetMapping 不支持@RequestBody ，使用PostMapping后面我改成以下代码就没有报错了

@PostMapping(value="/schedules/findUserSchedule",produces = MediaType.APPLICATION_JSON_VALUE)

public List<xxxxxx> findUser(@RequestBody xxxxxx xxxxx) {

log.debug("查询用户日程", xxxxxx);

}

或者是使用了get提交方式

情况三：

如果不是因为上面的两种情况，

请看这里：

我们在传输json数据的时候，假如json数据为空，那么就会报一个错误，就是Required request body is missing
这个的意思就是我们这个接口必须要传输json格式的数据，假如没有数据，就会报错返回错误的信息。

原文地址：https://blog.csdn.net/q1035331653/article/details/80370818