尝试使用IntelliJ在Java中创建基本登录页面。我已经使用这些说明将JAR添加到CLASSPATH中:Adding Jar files to IntellijIdea classpath。我得到的错误如下。IntelliJ java.lang.ClassNotFoundException:com.mysql.jdbc.Driver - 连接到XAMPP MySQL数据库
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 main.Validate.checkUser(Validate.java:17)
at main.Login.doPost(Login.java:23)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:661)
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)
20-Mar-2017 16:14:19.453 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deploying web application directory D:\Users\MYNAME\apache-tomcat-8.5.12\webapps\manager
20-Mar-2017 16:14:19.523 INFO [localhost-startStop-1] org.apache.catalina.startup.HostConfig.deployDirectory Deployment of web application directory D:\Users\MYNAME\apache-tomcat-8.5.12\webapps\manager has finished in 70 ms
连接到数据库的类称为验证;
package main;
import java.sql.*;
public class Validate
{
public static boolean checkUser(String username,String password)
{
boolean st =false;
try{
//loading drivers for mysql
Class.forName("com.mysql.jdbc.Driver");
//creating connection with the database
Connection con=DriverManager.getConnection
("jdbc:mysql:/ /localhost:3306/wpdcourseworkdb","root","");
PreparedStatement ps =con.prepareStatement
("select * from users where username=? and password=?");
ps.setString(1, username);
ps.setString(2, password);
ResultSet rs =ps.executeQuery();
st = rs.next();
}catch(Exception e)
{
e.printStackTrace();
}
return st;
}
}
除了添加一个新的项目库之外,您是否也将该库分配给了一个模块?右键单击库 - > _添加到模块..._。 –
请注意,通过向IntelliJ的类路径添加一个库,在IDE外部运行该程序时,该库不可用,例如,在不同的JVM中。 –
@ luc14n0 - 我已将库分配给模块作为依赖。 http://imgur.com/a/R072v这是我的库和模块目前的样子。这两个问题是工件中缺失的库。 – CDickson