編譯時錯誤：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

我還嘗試將 -cp 替換為類路徑，但每次仍然出現以下錯誤：

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 上嘗試了其他 Servlet java 程序以及它，它甚至可以幫助我自己完美地運行，但我無法明確地解決每個可能的解決方案。

Answer 1

Tomcat 10 目前是一個里程碑式的版本，因此對於第一步或有意義的開發工作來說並不是很好，除非您在問題的根本原因之后特別想要 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.* .

與其立即調整所有內容，不如僅將 Tomcat 9 和 go 與舊的（隨處記錄的） javax.servlet.*