我成功地连接了一个简单的java应用程序，该应用程序通过声明适当的方式打印出所有数据并将MySQL连接器jar文件导入到项目中。但是，问题在于我想通过Web应用程序（glassfish）连接到MySQL。我已经导入了MySQL连接器jar文件并对其进行了适当的声明，但我不明白为什么驱动程序没有被找到。
以下是我收到的错误：
2016 - 01 - 29T16: 22: 25.873 + 0000 | Info: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at org.glassfish.web.loader.WebappClassLoader.loadClass(WebappClassLoader.java: 1783)
at org.glassfish.web.loader.WebappClassLoader.loadClass(WebappClassLoader.java: 1633)
at org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java: 187)
at org.apache.jasper.servlet.JasperLoader.loadClass(JasperLoader.java: 125)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java: 264)
at org.apache.jsp.validate_jsp._jspService(validate_jsp.java: 56)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java: 111)
at javax.servlet.http.HttpServlet.service(HttpServlet.java: 790)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java: 411)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java: 473)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java: 377)
at javax.servlet.http.HttpServlet.service(HttpServlet.java: 790)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java: 1682)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java: 318)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java: 160)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java: 734)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java: 673)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java: 99)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java: 174)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java: 416)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java: 283)
at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java: 459)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java: 167)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java: 206)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java: 180)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java: 235)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java: 119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java: 283)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java: 200)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java: 132)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java: 111)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java: 77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java: 536)
at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java: 112)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java: 117)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java: 56)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java: 137)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java: 591)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java: 571)
at java.lang.Thread.run(Thread.java: 745)
Validate.jsp
<% @page language = "java"
contentType = "text/html; charset=ISO-8859-1"
pageEncoding = "ISO-8859-1" %>
< !DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd" >
<% @page import = "java.sql.*" %>
<%
try {
String username = request.getParameter("username");
String password = request.getParameter("password");
String driver = ("com.mysql.jdbc.Driver");
Class.forName(driver); // MySQL database connection
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost/ebooking" + "user=user&password=user");
PreparedStatement pst = conn.prepareStatement("Select * from student where stu_username=? and stu_password=?");
pst.setString(1, username);
pst.setString(2, password);
ResultSet rs = pst.executeQuery();
if (rs.next())
out.println("Valid login credentials");
else
out.println("Invalid login credentials");
} catch (Exception e) {
System.out.println(e);
out.println("Something went wrong !! Please try again");
} %>
答案 0 :(得分：0)
确保已将mysql library文件添加到库
中也
在用户
之前添加?
变化：
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost/ebooking" + "user=user&password=user");
到
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost/ebooking" + "?user=user&password=user");
答案 1 :(得分：0)
任何JDBC api调用都需要底层数据库支持的合适的jdbc驱动程序。
请检查您的应用程序WAR文件，其中包含MYSQL数据库的jdbc驱动程序。
如果未在JVM的类加载器中加载jar，则会发生ClassNotFoundException答案 2 :(得分：0)
我认为你的方法getConnection有问题。这个方法正在等待三个参数。
import java.sql.Connection;
import java.sql.DriverManager;
public class JavaConnect {
public static void ImportDriver() {
try {
Class.forName("com.mysql.jdbc.Driver");
}
catch(ClassNotFoundException ex) {
ex.printStackTrace();
}
}
public static Connection ConnectDB() {
Connection connection = null;
String url = "jdbc:mysql://localhost/ebooking";
try {
connection = DriverManager.getConnection(url, "user", "user");
return connection;
}
catch(Exception ex) {
ex.printStackTrace();
System.out.println("Please try again !");
}
return connection;
}
}
我希望这会对你有所帮助！祝你有个美好的一天！
答案 3 :(得分：0)
尝试编写连接字符串，可能会添加port和ebooking?而不是ebooking，如下所示：
Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:8080/ebooking?" +
"user=user&password=user");
并且不要忘记添加可用的jdbc driver。