错误：java.lang.ClassNotFoundException:com.mysql.jdbc.Driver？

我正在尝试使用servlet和jdbc连接到MySQL数据库的简单登录身份验证。在tomcat服务器上执行后，出现以下错误：

java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1720)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1571)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at com.leader.prog.Validate.checkUser(Validate.java:13)
at com.leader.servlet.Login1.doPost(Login1.java:42)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2466)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2455)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Unknown Source)

我正在共享所有文件的内容：

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <servlet>
 <servlet-name>login</servlet-name>
    <servlet-class>com.leader.servlet.Login1</servlet-class>
  </servlet>
   <servlet-mapping>
<servlet-name>login</servlet-name>
<url-pattern>/login</url-pattern>
  </servlet-mapping>


   <servlet>
<servlet-name>welcome</servlet-name>
<servlet-class>com.leader.servlet.Welcome</servlet-class>
   </servlet>
  <servlet-mapping>
<servlet-name>welcome</servlet-name>
<url-pattern>/welcome</url-pattern>
  </servlet-mapping>


  <welcome-file-list>
<welcome-file>Home.html</welcome-file>
  </welcome-file-list>
</web-app>

validate.java

package com.leader.prog;
import java.sql.*;

public class Validate
 {

 public static boolean checkUser(String user,String pass) 
 {
  boolean st =false;
  try{

 //loading driver 
     Class.forName("com.mysql.jdbc.Driver");

 //creating connection with the database 
     Connection con=DriverManager.getConnection
                    ("jdbc:mysql://localhost:3306/person","root","password");
     PreparedStatement ps =con.prepareStatement
                         ("select * from person where pid=? and password=?");
     ps.setString(1, user);
     ps.setString(2, pass);
     ResultSet rs =ps.executeQuery();
     st = rs.next();

  }catch(Exception e)
  {
      e.printStackTrace();
  }
     return st;                 
 }   
 }

---

请帮我解决这个问题。

检查mysql驱动程序是否在classpath中可用。如果您使用的是IDE（eclipse），请尝试将其添加到构建路径。

您应该将Mysql连接器库添加到您的项目构建路径中

您可以从

或

package com.leader.prog;
import java.sql.*;

public class Validate
 {

 public static boolean checkUser(String user,String pass) 
 {
  boolean st =false;
  try{

 //loading driver 
     Class.forName("com.mysql.jdbc.Driver");

 //creating connection with the database 
     Connection con=DriverManager.getConnection
                    ("jdbc:mysql://localhost:3306/person","root","password");
     PreparedStatement ps =con.prepareStatement
                         ("select * from person where pid=? and password=?");
     ps.setString(1, user);
     ps.setString(2, pass);
     ResultSet rs =ps.executeQuery();
     st = rs.next();

  }catch(Exception e)
  {
      e.printStackTrace();
  }
     return st;                 
 }   
 }