无法使用MySQL创建类的JDBC驱动程序

Question

这个问题被多次询问..但仍然无法解决我的问题，我无法找到我的错误。

我正在尝试使用STS创建动态Web项目。我得到了以下stacktrace

org.apache.tomcat.dbcp.dbcp.SQLNestedException: Cannot create JDBC driver of class '' for connect URL 'null'
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createConnectionFactory(BasicDataSource.java:1452)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createDataSource(BasicDataSource.java:1371)
at org.apache.tomcat.dbcp.dbcp.BasicDataSource.getConnection(BasicDataSource.java:1044)
at actions.OneServlet.doGet(OneServlet.java:52)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:620)
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:501)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
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:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.sql.SQLException: No suitable driver
    at java.sql.DriverManager.getDriver(DriverManager.java:315)
    at org.apache.tomcat.dbcp.dbcp.BasicDataSource.createConnectionFactory(BasicDataSource.java:1437)
    ... 25 more

我的web.xml是：

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
    <display-name>ServletConnectionPool</display-name>

    <resource-ref>
    <description>MySQL Connection</description>
    <res-ref-name>jdbc/MySQLDB</res-ref-name>
    <res-type>javax.sql.DataSource</res-type>
    <res-auth>Container</res-auth>
    </resource-ref>

    <servlet>
        <description>
        </description>
        <display-name>OneServlet</display-name>
        <servlet-name>OneServlet</servlet-name>
        <servlet-class>actions.OneServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>OneServlet</servlet-name>
        <url-pattern>/OneServlet</url-pattern>
    </servlet-mapping>
    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>index.htm</welcome-file>
        <welcome-file>index.jsp</welcome-file>
        <welcome-file>default.html</welcome-file>
        <welcome-file>default.htm</welcome-file>
        <welcome-file>default.jsp</welcome-file>
    </welcome-file-list>
</web-app>

我的Context.xml是

<?xml version="1.0" encoding="UTF-8"?>
<Context>
    <Resource name="jdbc/MySQLDB" auth="Container" type="javax.sql.DataSource"    
        maxTotal="100"
        maxIdle="30" maxWaitMillis="10000" username="root" password="-----"     
        driverClassName="com.mysql.jdbc.Driver"
        url="jdbc:mysql://localhost:3306/hcq"/>
</Context>

我的连接池类是

package actions;

import java.sql.SQLException;

import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;

public class DSource {
    public static DataSource getDataSource() {
        DataSource ds=null;
        Context initCtx,envCtx;
        initCtx=envCtx=null;
        try {
            initCtx=new InitialContext();
            envCtx=(Context)initCtx.lookup("java:comp/env");
            ds=(DataSource)envCtx.lookup("jdbc/MySQLDB");
        }
        catch(NamingException e) {
            e.printStackTrace();
        }
        return ds;
    }
}

我的主要Servlet是

package actions;

import actions.DSource;

import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;


import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;

/**
 * Servlet implementation class OneServlet
 */
public class OneServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public OneServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub

        response.setContentType("text/html");
        PrintWriter out=response.getWriter();
        out.println("Details of Employee");

        PreparedStatement stmt;
        ResultSet rset;

        DataSource ds=DSource.getDataSource();
        System.out.println(ds);

        if(ds!=null) {
            try(Connection con=ds.getConnection()) {
                 stmt=con.prepareStatement("select * from Employee");
                 rset=stmt.executeQuery();
                 while(rset.next()) {
                     out.println("<br>"+rset.getString(1)+"\t"+rset.getString(2));
                 }
            }
            catch(SQLException e) {
                e.printStackTrace();
            }
        } else {
            out.println("Connection Failed");
        }
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    doGet(request,response);
    }
}

mysql-connector jar在WEB-INF / lib和Libraries / apachetomcat中都可用

我无法找到错误。