编译时错误：package javax.servlet 不存在 import javax.servlet.*

Question

I have set class path as follow: CLASS_PATH: C:\Program Files\Apache Software Foundation\Tomcat 10.0\lib;C:\Program Files (x86)\Java\mysql-connector.jar;C:\Program Files (x86) \Java\sqljdbc_8.2\enu\mssql-jdbc-8.2.0.jre8.jar;

and I also tried using jar file at compile time:- java -cp C:\Program Files\Apache Software Foundation\Tomcat 10.0\lib\servlet-api.jar Hello.java

java -cp "C:\Program Files\Apache Software Foundation\Tomcat 10.0\lib\servlet-api.jar" Hello.java

java -cp .;C:\Program Files\Apache Software Foundation\Tomcat 10.0\lib\servlet-api.jar Hello.java

java -cp ".;"C:\Program Files\Apache Software Foundation\Tomcat 10.0\lib\servlet-api.jar" Hello.java

java -cp C:\Program Files\Apache Software Foundation\Tomcat 10.0\lib\servlet-api.jar;. Hello.java

java -cp "C:\Program Files\Apache Software Foundation\Tomcat 10.0\lib\servlet-api.jar";. Hello.java

我还尝试将 -cp 替换为类路径，但每次仍然出现以下错误：

C:\Program Files\Apache Software Foundation\Tomcat 10.0\webapps\16 servlet\WEB-INF\classes>javac -cp .;servlet-api.jar; Hello.java
Hello.java:2: error: package javax.servlet does not exist
import javax.servlet.*;
^

Hello.java:3: error: cannot find symbol
public class Hello implements Servlet
                              ^
  symbol: class Servlet

Hello.java:5: error: cannot find symbol
        public void init(ServletConfig sc)throws ServletException
                         ^
  symbol:   class ServletConfig
  location: class Hello

Hello.java:5: error: cannot find symbol
        public void init(ServletConfig sc)throws ServletException
                                                 ^
  symbol:   class ServletException
  location: class Hello

Hello.java:9: error: cannot find symbol
        public ServletConfig getServletConfig()
               ^
  symbol:   class ServletConfig
  location: class Hello

Hello.java:13: error: cannot find symbol
        public void service(ServletRequest req,ServletResponse res)throws ServletException
                            ^
  symbol:   class ServletRequest
  location: class Hello

Hello.java:13: error: cannot find symbol
        public void service(ServletRequest req,ServletResponse res)throws ServletException
                                               ^
  symbol:   class ServletResponse
  location: class Hello

Hello.java:13: error: cannot find symbol
        public void service(ServletRequest req,ServletResponse res)throws ServletException
                                                                          ^
  symbol:   class ServletException
  location: class Hello
8 errors

我的 Hello.java Servlet 文件：-

    import java.io.*;
    import javax.servlet.*;

public class Hello implements Servlet
{
    public void init(ServletConfig sc)throws ServletException
    {

    }
    public ServletConfig getServletConfig()
    {
        return null;
    }
    public void service(ServletRequest req,ServletResponse res)throws ServletException
    {
        String name=req.getParameter("name");
        PrintWriter out=res.getWriter();
        out.println("Hello "+name);
    }
    public String getServletInfo()
    {
        return null;
    }
    public void destroy()
    {

    }
}

tbh 我在 netbeans IDE 上尝试了其他 Servlet java 程序以及它，它甚至可以帮助我自己完美地运行，但我无法明确地解决每个可能的解决方案。

Answer 1

Tomcat 10 目前是一个里程碑式的版本，因此对于第一步或有意义的开发工作来说并不是很好，除非您在问题的根本原因之后特别想要 go：

Tomcat 10 is not backwards compatible as the whole Java EE (or whatever label it flew under) is now replaced with the new Jakarta EE, thus your import javax.servlet.* now needs to be import jakarta.servlet.* .

与其立即调整所有内容，不如仅将 Tomcat 9 和 go 与旧的（随处记录的） javax.servlet.*