java - Jsp扩展页面指令异常: Unable to compile class for JSP:

Question

我正在尝试通过使用 JSP 扩展页面指令来制作一个示例，首先我在我的项目源代码区域中构建了一个简单的 java 类文件。项目正在 Eclipse IDE 中构建。

代码在这里:

package com.coderbd.extend;

public class Test {

    public String testMethod(){
        return "Hello";
    }

}

首先是 JSP 页面，我使用扩展页面指令扩展了类:<%@ page extends="com.coderbd.extend.Test" %>然后在我的index.jsp页面，我创建了 Test 的对象类如:

<%
    Test t= new Test();
    t.testMethod();
%>

最后尝试打印:

<%
    out.println(""+ testMethod());
%>

我在我的 lib 中使用了以下 jar 在 WEB-INF 下文件夹。

1. jasper.jar
2. org.apache.jasper.jar
3. javax.servlet-api-3.0.jar
4. javax.el-api.jar
5. javax.servlet-3.0.jar

但是我看到，我的 Tomcat 服务器给出了以下错误:

HTTP Status 500 - Unable to compile class for JSP:

type Exception report

message Unable to compile class for JSP:

description The server encountered an internal error that prevented it from fulfilling this request.

exception

org.apache.jasper.JasperException: Unable to compile class for JSP: 

An error occurred at line: [32] in the generated java file: [E:\The Java Spring Tutorial Learn Java's Popular Web Framework\JSP\work-space\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\work\Catalina\localhost\jsp-sec-4-lec-3\org\apache\jsp\index_jsp.java]
The method getServletConfig() is undefined for the type index_jsp

An error occurred at line: [33] in the generated java file: [E:\The Java Spring Tutorial Learn Java's Popular Web Framework\JSP\work-space\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\work\Catalina\localhost\jsp-sec-4-lec-3\org\apache\jsp\index_jsp.java]
The method getServletConfig() is undefined for the type index_jsp

An error occurred at line: [54] in the generated java file: [E:\The Java Spring Tutorial Learn Java's Popular Web Framework\JSP\work-space\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\work\Catalina\localhost\jsp-sec-4-lec-3\org\apache\jsp\index_jsp.java]
The method getPageContext(Servlet, ServletRequest, ServletResponse, String, boolean, int, boolean) in the type JspFactory is not applicable for the arguments (index_jsp, HttpServletRequest, HttpServletResponse, null, boolean, int, boolean)

Stacktrace:
    org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:103)
    org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:331)
    org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:468)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:378)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:353)
    org.apache.jasper.compiler.Compiler.compile(Compiler.java:340)
    org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:646)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:357)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:390)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

请帮助我使用 jsp extends page 指令修复示例。

Answer 1

从 WEB-INF/lib 中删除所有这些 jar。这些是 Tomcat 内部使用的 jar 文件。它们不应该在您的网络应用程序中。

并删除 extends="com.coderbd.extend.Test":它没有任何意义。您的 JSP 创建一个 Test 实例并使用它。它不需要(也不能)扩展它。