Java Servlet Error
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Exception Handling In Servlet And Jsp
Today we will look into Servlet Exception and Error Handling. Sometime back I wrote a post servlet error page about Exception Handling in Java but when it comes to web application, we need more than normal exception handling in java.Servlet ExceptionIf you notice, doGet() and web.xml error-page exception-type doPost() methods throw javax.servlet.ServletException and IOException, let's see what happens when we throw these exception from our application. I will write a simple servlet that will throw the ServletException. package com.journaldev.servlet.exception; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; @WebServlet("/MyExceptionServlet") public class MyExceptionServlet extends HttpServlet { private static final long
Servlet Throw Exception
serialVersionUID = 1L; protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { throw new ServletException("GET method is not supported."); } } Now when we invoke this servlet through browser with GET method, we get response like below image.Since browser understand only HTML, when our application throw exception, servlet container processes the exception and generate a HTML response. This logic is specific to servlet container. I am using tomcat and getting this error page. If you will use some other servers like JBoss or Glassfish, you might get different error HTML response.The problem with this response is that it's of no value to user. Also it's showing our application classes and server details to user that makes no sense to user and it's not good from security point of view.Servlet ErrorI am sure you must have seen 404 error when you are trying to hit a URL that doesn't exists. Let's see how our servlet container responds
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and an exception caught in your servlet can be logged how policies of this site About Us Learn more about Stack Overflow the servlet filter exception handling company Business Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags
Servlet Exception Is Checked Or Unchecked
Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes http://www.journaldev.com/1973/servlet-exception-and-error-handling-example-tutorial a minute: Sign up How to Properly Handle Exceptions in a JSP/Servlet App? up vote 9 down vote favorite 3 How do you properly handle errors encountered in a servlet? Right now, the app that I inherited (uses only plain JSP/Servlet) has a superclass called Controller which extends HttpServlet and which all other servlets extend from. In that Controller class is http://stackoverflow.com/questions/6182771/how-to-properly-handle-exceptions-in-a-jsp-servlet-app a try and catch block like the following: try { // execute doPost or doGet here } catch (Exception e) { // show a generic error page } Is this the proper way of doing it? It seems clunky and doesn't seem to always work. I'm only an intern so I don't have a lot of experience with this. Any advice? I'm trying to make the app for robust.. java jsp servlets share|improve this question asked May 31 '11 at 3:37 Damian Wells 48115 A related question that gives an example of handling exceptions in a filter, which is another option in addition to the answer below (that question is in the context of Spring but still applies). –Jason C Aug 30 at 14:31 add a comment| 4 Answers 4 active oldest votes up vote 16 down vote accepted The standard thing to do is have your Servlet's doXxx() method (eg. doGet(), doPost(), etc.) throw a ServletException and allow the container to catch and handle it. You can specify a custom error page to be shown in WEB-INF/web.xml u
Certification Databases Caching Books Engineering Languages Frameworks Products This Site Careers Other all forums Forum: Servlets https://coderanch.com/t/353805/Servlets/java/Error-Internal-servlet-error Error 500- Internal servlet error Soumendu Munshi Greenhorn Posts: 11 posted 14 years ago Hello, I am a new servlet user trying to test with Servlet. http://books.gigatux.nl/mirror/javaservletjspcookbook/0596005725_jsvltjspckbk-chp-9-sect-2.html I am using Apache 1.3 and Tomcat 3.2, conneting Tomcat and apache using Mod_jk on Win98. Problem: I wrote a small Servlet (book eg) HelloWorld. It servlet error compiled well and I placed that at Tomcat_home/webapps/my-apps/ directory. So now when I try to execute the servlet using http://localhost:8080/my-apps/HelloWorld it gives an error Error: 500 Location: /my-apps/HelloWorld Internal Servlet Error: java.lang.NoClassDefFoundError: HelloWorld (wrong name: Helloworld) at java.lang.ClassLoader.defineClass0(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:486) ......... etc Could anybody suggest what went wrong. Thanks Soum. java servlet error Craig Arthur Greenhorn Posts: 5 posted 14 years ago I had some fun with this yesterday. 1. Have you edited the "server.xml" file in the "conf" directory? You need an entry for your "my-apps" folder, something like:
codes to the servlet in the deployment descriptor. Discussion An error-handling servlet has access to several request attributes that it can use to describe the error. The error page also has access to the request and response objects associated with the page that generated the error. For example, the java.lang.Throwable object associated with any exceptions can be accessed with the following code: Throwable throwable = (Throwable) request.getAttribute("javax.servlet.error.exception"); You can access the server response code with this code: String status_code = ((Integer) request.getAttribute("javax.servlet.error.status_code")).toString( ); Table 9-1 shows the request attributes that an error-handling servlet has access to. Table 9-1. Request attributes available to servlet error pages Request attribute Java type javax.servlet.error.status_code java.lang.Integer javax.servlet.error.exception_type java.lang.Class javax.servlet.error.message java.lang.String javax.servlet.error.exception java.lang.Throwable javax.servlet.error.request_uri java.lang.String javax.servlet.error.servlet_name java.lang.String Example 9-2 shows the ErrorGen servlet. The web container invokes this servlet when another servlet or JSP throws an unhandled Throwable, according to the configuration in Example 9-1. Example 9-2. An error-handling servlet package com.jspservletcookbook; import javax.servlet.*; import javax.servlet.http.*; public class ErrorGen extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, java.io.IOException { //check the servlet exception Throwable throwable = (Throwable) request.getAttribute("javax.servlet.error.exception"); String servletName = (String) request.getAttribute("javax.servlet.error.servlet_name"); if (servletName == null) servletName = "Unknown"; String requestUri = (String) request.getAttribute("javax.servlet.error.request_uri"); if (requestUri == null) requestUri = "Unknown"; response.setContentType("text/html"); java.io.PrintWriter out = response.getWriter( ); out.println(""); out.println("
"); out.p