我的任务是将网站从一个机构迁移到另一个机构。作为流程的一部分，我们尝试更新网站使用的版本。
最初我被要求使用Java 8和Tomcat 5.5（在Linux上），这导致了问题。此后我尝试使用Java 8将Web应用程序部署到Tomcat 9.部分Web应用程序似乎运行良好（并解决了我使用Tomcat5时遇到的问题）。但是，当我转到index.jsp时，主app会抛出JasperException - 部署到Tomcat 5.5的同一个Web应用程序没有问题。
org.apache.jasper.JasperException: Unable to compile class for JSP:
An error occurred at line: [15] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
The type index_jsp must implement the inherited abstract method JspSourceImports.getPackageImports()
An error occurred at line: [15] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
The type index_jsp must implement the inherited abstract method JspSourceImports.getClassImports()
An error occurred at line: [15] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
The type index_jsp must implement the inherited abstract method JspSourceDependent.getDependants()
An error occurred at line: [22] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
The type Map is not generic; it cannot be parameterized with arguments <String, Long>
An error occurred at line: [24] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
The type Set is not generic; it cannot be parameterized with arguments <String>
An error occurred at line: [26] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
The type Set is not generic; it cannot be parameterized with arguments <String>
An error occurred at line: [29] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
_jspx_imports_packages cannot be resolved to a variable
An error occurred at line: [29] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
The type HashSet is not generic; it cannot be parameterized with arguments <>
An error occurred at line: [30] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
_jspx_imports_packages cannot be resolved
An error occurred at line: [31] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
_jspx_imports_packages cannot be resolved
An error occurred at line: [32] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
_jspx_imports_packages cannot be resolved
An error occurred at line: [33] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
_jspx_imports_classes cannot be resolved to a variable
An error occurred at line: [39] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
The type Map is not generic; it cannot be parameterized with arguments <String, Long>
An error occurred at line: [40] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
_jspx_dependants cannot be resolved to a variable
An error occurred at line: [43] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
The type Set is not generic; it cannot be parameterized with arguments <String>
An error occurred at line: [44] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
_jspx_imports_packages cannot be resolved to a variable
An error occurred at line: [47] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
The type Set is not generic; it cannot be parameterized with arguments <String>
An error occurred at line: [48] in the generated java file: [/opt/tomcat9/work/Catalina/localhost/home/org/apache/jsp/index_jsp.java]
_jspx_imports_classes cannot be resolved to a variable
Stacktrace:
org.apache.jasper.compiler.DefaultErrorHandler.javacError(DefaultErrorHandler.java:103)
org.apache.jasper.compiler.ErrorDispatcher.javacError(ErrorDispatcher.java:213)
org.apache.jasper.compiler.JDTCompiler.generateClass(JDTCompiler.java:458)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:389)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:361)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:345)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:603)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:369)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
edu.purdue.cybercenter.ionomics.servlet.PiiMS.doGet(PiiMS.java:83)
javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
我发现的大多数类似问题都表明这与jar文件有关，可能还有某种冲突。但是，tomcat 9的lib结构与tomcat5不同，我不确定哪个jar可能导致这种情况。我还尝试将index.jsp更改为更简单的（HelloWorld）表单 - 删除任何代码，抛出相同的异常。
是否有人遇到类似问题和/或有任何建议？
感谢。
答案 0 :(得分：0)
在这种特殊情况下，问题是应用程序WEB-INF/lib目录中的许多库确实需要删除，包括：
rt.jar servlet-api.jar 我正在回答这个问题和建议将其关闭，因为这是一个“简单的错误”，但有些读者可能会发现查看分辨率实际上是有用的。