-- Learn not just technology, but dreams! Home HTML JAVASCRIPT CSS VUE REACT PYTHON3 JAVA C C++ C# AI GO SQL LINUX VS CODE BOOTSTRAP GIT Local Bookmarks JSP Tutorial JSP Tutorial JSP Introduction JSP Development Environment Setup Eclipse JSP/Servlet JSP Structure JSP Life Cycle JSP Syntax JSP Directives JSP Action Elements JSP Implicit Objects JSP Client Request JSP Server Response JSP HTTP Status Codes JSP Form Processing JSP Filters JSP Cookie Handling JSP Session JSP File Upload JSP Date Processing JSP Page Redirection JSP Hit Counter JSP Auto Refresh JSP Sending Email JSP Advanced Tutorial JSP Standard Tag Library (JSTL) JSP Database Connection JSP XML Data Processing JSP JavaBean JSP Custom Tags JSP Expression Language JSP Exception Handling JSP Debugging JSP Internationalization JSP Expression Language JSP Debugging Deep Dive Development Tools Software Programming Languages Scripting Languages Computer Science Web Service Programming Web Services Web Design & Development Scripts JSP Exception Handling When writing JSP programs, programmers may miss some bugs, which can appear anywhere in the program. There are generally several types of exceptions in JSP code: Checked Exceptions: A checked exception is a typical user error or an error that a programmer cannot foresee. For example, if a file is about to be opened but cannot be found, an exception is thrown. These exceptions cannot be simply ignored at compile time. Runtime Exceptions: A runtime exception may have been avoided by the programmer, and this type of exception will be ignored at compile time. Errors: Errors are not exceptions, but the problem is that they are beyond the control of the user or programmer. Errors are usually ignored in code, and there is little you can do about them. For example, a stack overflow error. These errors are ignored at compile time. This section will provide a few simple and elegant ways to handle runtime exceptions and errors. Using the Exception Object The exception object is an instance of a subclass of Throwable and is only available on error pages. The following table lists some important methods in the Throwable class: Number Method & Description 1 public String getMessage() Returns the message of the exception. This message is initialized in the Throwable constructor. 2 public Throwable getCause() Returns the cause of the exception, as a Throwable object. 3 public String toString() Returns the class name. 4 public void printStackTrace() Outputs the exception stack trace to System.err. 5 public StackTraceElement [] getStackTrace() Returns the exception stack trace as an array of stack trace elements. 6 public Throwable fillInStackTrace() Fills the Throwable object with the current stack trace. JSP provides the option to specify an error page for each JSP page. Whenever an exception is thrown from the page, the JSP container will automatically invoke the error page. The following example specifies an error page for main.jsp. Use the directive to specify an error page. Now, write the ShowError.jsp file as follows:

Opps...

Sorry, an error occurred.

Here is the exception stack trace:

Note that the ShowError.jsp file uses the directive, which tells the JSP compiler to generate an exception instance variable. Now try to access the main.jsp page, it will produce the following result: java.lang.RuntimeException: Error condition!!! ...... Opps... Sorry, an error occurred. Here is the exception stack trace: ... Using JSTL Tags in the Error Page You can use JSTL tags to write the error page ShowError.jsp. The code in this example is logically almost the same as the previous example, but the code in this example has better structure and can provide more information:

Opps...

Error:	${pageContext.exception}
URI:	${pageContext.errorData.requestURI}
Status code:	${pageContext.errorData.statusCode}
Stack trace:	${trace}

The result is as follows: ... Using try…catch Blocks If you want to handle exceptions within a single page and handle different exceptions differently, then you need to use try…catch blocks. The following example shows how to use try…catch blocks. Put this code in main.jsp: Try to access main.jsp, it will produce the following result: An exception occurred: / by zero JSP Expression Language JSP Debugging ByteDance Coding Plan Supports mainstream large models like Doubao, GLM, DeepSeek, Kimi, MiniMax, officially supplied, stable and reliable. Configuration Guide ¥9.9 / month Subscribe Now iFlytek Star Coding Plan Includes free model call quota, DeepSeek, GLM, Kimi, MiniMax, one-stop experience and deployment platform. Configuration Guide ¥3.9 / month Subscribe Now Click here to share notes Category Navigation Python / Data Science AI / Intelligent Development Front-end Development Back-end Development Database Mobile Development DevOps / Engineering Programming Languages Computer Fundamentals XML / Web Service .NET Website Construction Advertisement JSP Tutorial JSP Tutorial JSP Introduction JSP Development Environment Setup Eclipse JSP/Servlet JSP Structure JSP Life Cycle JSP Syntax JSP Directives JSP Action Elements JSP Implicit Objects JSP Client Request JSP Server Response JSP HTTP Status Codes JSP Form Processing JSP Filters JSP Cookie Handling JSP Session JSP File Upload JSP Date Processing JSP Page Redirection JSP Hit Counter JSP Auto Refresh JSP Sending Email JSP Advanced Tutorial JSP Standard Tag Library (JSTL) JSP Database Connection JSP XML Data Processing JSP JavaBean JSP Custom Tags JSP Expression Language JSP Exception Handling JSP Debugging JSP Internationalization Online Examples ·HTML Examples ·CSS Examples ·JavaScript Examples ·Ajax Examples ·jQuery Examples ·XML Examples ·Java Examples Character Sets & Tools · HTML Character Set Settings · HTML ASCII Character Set · JS Obfuscation/Encryption · PNG/JPEG Image Compression · HTML Color Picker · JSON Formatting Tool · Random Number Generator Latest Updates · AI Beginner Tutorial · Large Model Multimodal (M... · Codex Advanced Configuration · AI Agent Terminology · ZCode Beginner Tutorial · Loop Engineerin... · Claude Code Us... Site Information · Feedback · Disclaimer · About Us · Article Archive Follow WeChat My Collection Mark Article Browsing History Clear All No records yet