linux - 无法找到错误的位置

Question

我的服务器日志充满了以下错误消息不知道在哪里可以找到这个问题，我有基于 Spring 的 MVC Controller 。我检查了每个地方但找不到。 (Tomcat 8, AWS Linux)

org.springframework.beans.TypeMismatchException: Failed to convert value of type 'java.lang.String' to required type 'java.lang.Integer'; nested exception is java.lang.NumberFormatException: For input string: "null"
        at org.springframework.beans.TypeConverterSupport.doConvert(TypeConverterSupport.java:77)
        at org.springframework.beans.TypeConverterSupport.convertIfNecessary(TypeConverterSupport.java:47)
        at org.springframework.validation.DataBinder.convertIfNecessary(DataBinder.java:603)
        at org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver.resolveArgument(AbstractNamedValueMethodArgumentResolver.java:104)
        at org.springframework.web.method.support.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:77)
        at org.springframework.web.method.support.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:162)
        at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:129)
        at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:776)
        at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:705)
        at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
        at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:959)
        at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:893)
        at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)
        at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
        at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
        at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:85)
        at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
        at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
        at org.apache.catalina.valves.RemoteIpValve.invoke(RemoteIpValve.java:676)
        at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:522)
        at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1095)
        at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:672)
        at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1500)
        at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1456)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$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)
Caused by: java.lang.NumberFormatException: For input string: "null"
        at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
        at java.lang.Integer.parseInt(Integer.java:580)
        at java.lang.Integer.valueOf(Integer.java:766)
        at org.springframework.util.NumberUtils.parseNumber(NumberUtils.java:193)
        at org.springframework.beans.propertyeditors.CustomNumberEditor.setAsText(CustomNumberEditor.java:113)
        at org.springframework.beans.TypeConverterDelegate.doConvertTextValue(TypeConverterDelegate.java:450)
        at org.springframework.beans.TypeConverterDelegate.doConvertValue(TypeConverterDelegate.java:423)
        at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:195)
        at org.springframework.beans.TypeConverterDelegate.convertIfNecessary(TypeConverterDelegate.java:107)
        at org.springframework.beans.TypeConverterSupport.doConvert(TypeConverterSupport.java:64)
        ... 43 more

Answer 1

在这里，我给出了你最好记录错误和异常的方式，这可以帮助你轻松调试错误。

<强>1。记录请求url(controller url)和请求参数- 在分配给 Controller 之前记录请求 url 及其参数。意味着在它转到 Controller 处理程序方法之前记录它。 (这对你的情况很有帮助。因为当尝试转换与 Controller 处理程序方法参数对应的请求参数时，spring 在处理程序处理之前抛出异常)。通过这个你知道什么是哪个 Controller url 的参数

2.记录请求 url 和响应参数 再次记录请求 url 及其响应参数。这有助于识别为此 url 发送的响应

<强>3。使用请求 url 记录异常 - 如果您正在生成自己的自定义异常，如 CustomException。然后在 CustomException 类中创建一个字段，该字段采用 url，因此当您记录它时，您可以轻松识别为哪个 url 创建此异常。对于其他异常和错误，尝试创建通用异常处理程序类，并在该类中创建在 catch block 中调用的方法，该方法捕获 Throwable 并在该方法中记录打印堆栈跟踪

下面是示例代码:-

   public CustomException extends Exception{
    String requestUrl;
    String message;
    }

通用处理方法

     public static handleException(Throwable throwable, url){
      //Log print stack trace


      }

对于 Spring ，您可以使用 ExceptionHandler，您可以通过谷歌搜索轻松找到它

spring的第1点和第2点可以使用HandlerInterceptorAdapter，请了解下。

下面是示例代码

public class LogInteceptor extends HandlerInterceptorAdapter{

private static final Logger logger = LoggerFactory
    .getLogger(LogInteceptor.class);


//This method called before controller method handle the request
@Override
public boolean preHandle(HttpServletRequest request,
    HttpServletResponse response, Object handler) throws Exception {


//Log other things also 

//Logging the request url
logger.info("Request URL {} request param is {}" +  request.getRequestURL().toString(), request);
//if returned false, we need to make sure 'response' is sent
return true;
}

//This called before the model view send to view page for render
@Override
public void postHandle(HttpServletRequest request,
        HttpServletResponse response, Object handler,
        ModelAndView modelAndView) throws Exception {
    //we can add attributes in the modelAndView and use that in the view page
}

//This called when response is going to sent
@Override
public void afterCompletion(HttpServletRequest request,
    HttpServletResponse response, Object handler, Exception ex)
        throws Exception {

}

 }