java.lang.ClassNotFoundException : com. mysql.jdbc.Driver 即使在 Intellij 上使用 mySql Maven 依赖项之后

Question

我正在将 Intellij 用于 servlet 项目并使用 maven

 <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>6.0.6</version>
 </dependency>

据我所知，这应该可以处理在 tomcat 网络服务器上部署 war 时所有与类路径相关的问题。

但我正在接受

08-Apr-2017 13:40:37.047 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory /Applications/tomcat/webapps/manager 08-Apr-2017 13:40:37.092 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory /Applications/tomcat/webapps/manager has finished in 44 ms java.lang.ClassNotFoundException: com.mysql.jdbc.Driver at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1285) at org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1119) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:264) at com.saurabh.testdb.TestDBServlet.doGet(TestDBServlet.java:34) at javax.servlet.http.HttpServlet.service(HttpServlet.java:635) at javax.servlet.http.HttpServlet.service(HttpServlet.java:742) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:230) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:192) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:165) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:198) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:478) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:140) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:80) at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:87) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:341) at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783) at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66) at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:798) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1441) at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) 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)

这是我加载驱动程序的代码

package com.saurabh.testdb;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;

@WebServlet("/TestDBServlet")
public class TestDBServlet extends HttpServlet {

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

    //set up connection variable
    String jdbcUrl = "jdbc:mysql://localhost:3306/web_customer_tracker?useSSL=false";
    String user = "springstudent";
    String pass = "sringstudent";
    String driver = "com.mysql.jdbc.Driver";

    try {

        PrintWriter out = resp.getWriter();

        out.println("Connecting to database: " + jdbcUrl);

        Class.forName(driver);

        Connection myConn = DriverManager.getConnection(jdbcUrl, user, pass);

        out.println("Connection successful!!!");

        myConn.close();

    } catch (Exception exc) {
        exc.printStackTrace();
    }
    }
}

Answer 1

你必须手动添加你的 jdbc_connector 到你的 tomcat 服务器，你应该将你的 jar 包含到这个文件夹 $TOMCAT_HOME/lib