Unable to compile class for JSP:Tomcat 9

问题

I'm using the latest TomCat version and I've recently installed Eclipse Java EE version so it's also the latest version. Btw I do have the latest version of JAVA SE (JDK).

This is my class:

    package jsp.demo;

public class ClassForJSP {

    public static String lowerCase(String data) {
        return data.toLowerCase();
    }
}

So this is my really simple jsp code:

<%@page import="jsp.demo.ClassForJSP"%>
<html>
<body>
    Let's make THIS STATEMENT lower case: <%= ClassForJSP.lowerCase("THIS STATEMENT") %>
</body>
</html>

I'm getting this error:

Type Exception Report

Message Unable to compile class for JSP:

Description The server encountered an unexpected condition that prevented it from fulfilling the request.

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

An error occurred at line: [14] in the generated java file: [D:\Java Projects.metadata.plugins\org.eclipse.wst.server.core\tmp0\work\Catalina\localhost\jspdemo\org\apache\jsp\callJavaClass_jsp.java] Only a type can be imported. jsp.demo.ClassForJSP resolves to a package

An error occurred at line: [4] in the jsp file: [/callJavaClass.jsp] ClassForJSP cannot be resolved 1: <%@page import="jsp.demo.ClassForJSP"%> 2: 3: 4: Let's make THIS STATEMENT lower case: <%= ClassForJSP.lowerCase("THIS STATEMENT") %> 5: 6:

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:473) org.apache.jasper.compiler.Compiler.compile(Compiler.java:392) org.apache.jasper.compiler.Compiler.compile(Compiler.java:362) org.apache.jasper.compiler.Compiler.compile(Compiler.java:346) org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:603) org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:399) org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:386) org.apache.jasper.servlet.JspServlet.service(JspServlet.java:330) javax.servlet.http.HttpServlet.service(HttpServlet.java:741) org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)

Note The full stack trace of the root cause is available in the server logs.

Apache Tomcat/9.0.14

回答1:

This message is telling:

Only a type can be imported. jsp.demo.ClassForJSP resolves to a package

The source code of your Java class indicates that the package is jsp.demo. But at runtime, the JSP compiler has found a package (i.e. a directory on the classpath) whose name is jsp.demo.ClassForJSP.

Clearly, something is wrong with the classpath ... and the JSP compiler has raised a red flag.

How come?

Maybe you are using a "stale" JAR file in the webapp deployed to the server?
Maybe you have missed a build or deployment step?
Maybe you have manually assembled the JAR file, or the WAR file that contains it, and have gotten the structure wrong?
Maybe you are doing this "live" on the Tomcat server, and you have copied a ".class" file to the wrong place?
Possibly something else?

You will need to look at all of these possibilities yourself.

来源：https://stackoverflow.com/questions/54338873/unable-to-compile-class-for-jsptomcat-9

标签

java

jsp