错误信息如下:
Servlet.service() for servlet [jsp] in context with path [/20161017] threw exception [/tag/simpleTag.jsp (line: 25, column: 44) Expecting "jsp:param" standard action with "name" and "value" attributes] with root cause
org.apache.jasper.JasperException: /tag/simpleTag.jsp (line: 25, column: 44) Expecting "jsp:param" standard action with "name" and "value" attributes
at org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:41)
at org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:275)
at org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:91)
at org.apache.jasper.compiler.Parser.parseParam(Parser.java:829)
at org.apache.jasper.compiler.Parser.parseBody(Parser.java:1681)
at org.apache.jasper.compiler.Parser.parseOptionalBody(Parser.java:1006)
at org.apache.jasper.compiler.Parser.parseForward(Parser.java:870)
at org.apache.jasper.compiler.Parser.parseStandardAction(Parser.java:1122)
at org.apache.jasper.compiler.Parser.parseElements(Parser.java:1459)
at org.apache.jasper.compiler.Parser.parse(Parser.java:139)
at org.apache.jasper.compiler.ParserController.doParse(ParserController.java:227)
at org.apache.jasper.compiler.ParserController.parse(ParserController.java:100)
at org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:199)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:356)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:336)
at org.apache.jasper.compiler.Compiler.compile(Compiler.java:323)
at org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:585)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:363)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:396)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:340)
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.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.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1100)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:687)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2508)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2497)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$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)
simple.jsp文件如下：
<%@ page import="java.util.* ,com.tt.javaweb.Customer" %>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<%
//模拟Servlet中的操作
List<Customer> customers = new ArrayList<Customer>();
customers.add(new Customer(1,"AA",12));
customers.add(new Customer(2,"BB",13));
customers.add(new Customer(3,"CC",14));
customers.add(new Customer(4,"DD",15));
customers.add(new Customer(5,"EE",16)); request.setAttribute("customers", customers); %> <jsp:forward page="testTag.jsp"></page:forward> </body>
</html>
testTag.jsp文件如下：
<%@ page import="java.util.* ,com.tt.javaweb.Customer" %>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body> <!-- 在页面上对request中的customers属性进行遍历，打印id,name,age -->
<%
List<Customer> customers = (List<Customer>)request.getAttribute("customers");
if(customers != null) {
for(Customer customer : customers){
%> <%= customer.getId() %> ,<%= customer.getName() %> ,<%= customer.getAge() %> <%
}
} %> </body>
</html>
原因：在simpleTag.jsp中的forward标签写错了！
总结该错误可能出现的原因：
1.标签的开始和结束不一致：比如我犯的这个错
2.没有结束标签：<jsp:forward page="testTag.jsp">,应该是<jsp:forward page="testTag.jsp"/>
3.没有参数的标签，结束时不能换行：
<jsp:forward page="testTag.jsp">
</jsp:forward>
应该是<jsp:forward page="testTag.jsp"></jsp:forward>