java - 编译时错误: package javax. servlet不存在导入javax.servlet.*

Question

我设置类路径如下: 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;

我还尝试在编译时使用 jar 文件:- 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

我也尝试用类路径替换 -cp，但每次仍然收到以下错误:

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

My 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()
    {

    }
}

说实话，我也在 netbeans IDE 上尝试了其他 Servlet java 程序，它运行得很好，但即使在搜索并尝试了所有可能的解决方案之后，我也无法自己显式配置它，请大家帮我解决它。

Answer 1

Tomcat 10 目前是一个里程碑构建，因此对于第一步或有意义的开发工作来说并不是很好，除非您特别想找出问题的根本原因:

Tomcat 10 不向后兼容，因为整个 Java EE(或它所属的任何标签)现在已被新的 Jakarta EE 取代，因此您的 import javax.servlet.* 现在需要导入 jakarta.servlet.*.

您可能会更乐意使用 Tomcat 9 并使用旧的(到处都有记录)javax.servlet.*

，而不是立即适应所有内容。