java.lang.RuntimeException : Failed : HTTP error code : 500

Question

我正在尝试检索 json 对象，然后使用其中存在的信息。但在 Json 请求时，它抛出运行时异常。这是代码

public URL getURL(){                

            try{                    
                URL domain = new URL("http.....");                  
                URL url = new URL(domain + cookieValue);                    
                System.out.println(url);                    
                return url;
            }
            catch (MalformedURLException ex) {                
                log_loginBean.logger(ex);
            }

            return null;    
        }

    public static JSONObject JSONRequest(URL url_comp){

                try {                        
                    URL url = url_comp;
                    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                    conn.setRequestMethod("GET");
                    conn.setRequestProperty("Accept", "application/json");

                    if (conn.getResponseCode() != 200) {
                        throw new RuntimeException("Failed : HTTP error code : "
                                + conn.getResponseCode());
                    }

                    BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));

                    String jsonText = readAll(br);
                    JSONObject json = new JSONObject(jsonText);       
                    conn.disconnect();                      
                    return json;

                  } 
                  catch (MalformedURLException e) {              
                      log_loginBean.logger(e);               
                  } 
                  catch (IOException e) {                
                      log_loginBean.logger(e);

                  } 
                  catch(JSONException e) {                      
                      log_loginBean.logger(e);
                  }

                return null;        
            }

        // This will extract some particular information (UserId, Email) from the extracted JSON Object. 

            public void parseJSON(){
              try{
                JSONObject obj = JSONRequest(getURL());
                userId = obj.getString("UserID");
                Email = obj.getString("Email");                 

              }
              catch(JSONException e){
                  log_loginBean.logger(e);
              } 
            }

这是我的堆栈跟踪

    SEVERE: Servlet.service() for servlet [Faces Servlet] in context with path [/CDCandTR] threw exception [Failed : HTTP error code : 500] with root cause
java.lang.RuntimeException: Failed : HTTP error code : 500
            at com.walmart.cdctraffic.login.LoginBean.JSONRequest(LoginBean.java:183)
            at com.walmart.cdctraffic.login.LoginBean.parseJSON(LoginBean.java:226)
            at com.walmart.cdctraffic.login.LoginBean.login(LoginBean.java:266)
            at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
            at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
            at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
            at java.lang.reflect.Method.invoke(Method.java:606)
            at org.apache.el.parser.AstValue.invoke(AstValue.java:278)
            at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:273)
            at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
            at com.sun.faces.facelets.tag.jsf.core.DeclarativeSystemEventListener.processEvent(EventHandler.java:128)
            at javax.faces.component.UIComponent$ComponentSystemEventListenerAdapter.processEvent(UIComponent.java:2603)
            at javax.faces.event.SystemEvent.processListener(SystemEvent.java:108)
            at javax.faces.event.ComponentSystemEvent.processListener(ComponentSystemEvent.java:118)
            at com.sun.faces.application.ApplicationImpl.processListeners(ApplicationImpl.java:2187)
            at com.sun.faces.application.ApplicationImpl.invokeComponentListenersFor(ApplicationImpl.java:2135)
            at com.sun.faces.application.ApplicationImpl.publishEvent(ApplicationImpl.java:289)
            at com.sun.faces.application.ApplicationImpl.publishEvent(ApplicationImpl.java:247)
            at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:107)
            at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
            at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:219)
            at javax.faces.webapp.FacesServlet.service(FacesServlet.java:647)
            at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
            at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
            at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
            at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
            at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
            at com.walmart.cdctraffic.utilities.ResponseHeaderFilter.doFilter(ResponseHeaderFilter.java:30)
            at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
            at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
            at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:203)
            at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
            at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:610)
            at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
            at com.walmart.infraweb.valves.SecureErrorReportValve.invoke(SecureErrorReportValve.java:102)
            at org.apache.catalina.valves.StuckThreadDetectionValve.invoke(StuckThreadDetectionValve.java:221)
            at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
            at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
            at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
            at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
            at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2440)
            at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2429)
            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
            at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
            at java.lang.Thread.run(Thread.java:745)

所以现在我无法找到它抛出 HTTP 500 错误的原因以及如何解决这一切？然后在IF语句之后，是否需要在finally中放入else并断开连接？请帮忙。

Answer 1

根据提供的堆栈跟踪，我怀疑您没有正确传递登录信息，因为它显然在 LoginBean 内的某个地方失败了:

com.walmart.cdctraffic.login.LoginBean.JSONRequest(LoginBean.java:183)