JSP操作mysql数据库
各位大神，小弟用myeclipse写了个web工程，其中一个jsp文件代码如下:<%@ page language="java" import="java.util.*,java.sql.*"
pageEncoding="gbk"%>
<%@page import="javax.servlet.jsp.tagext.TryCatchFinally"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
</head>
<body>
<%
//接收
String u = request.getParameter("username");
String p = request.getParameter("password");
//到数据库中验证用户
Connection conn=null;
Statement sm=null;
ResultSet rs=null;
try {
//1.加载驱动
Class.forName("com.mysql.jdbc.Driver");
//2.获得连接
conn = DriverManager.getConnection(
"jdbc:mysql://127.0.0.1:8080/mydb1", "root", "111111");
//3.创建Statement
sm = conn.createStatement();
//4.查询
rs = sm.executeQuery("select password from users where username='"+u+"'");
//根据查询结果判断
if (rs.next()) {
//说明用户名 存在
if (rs.getString(1).equals(p)) {
//一定是合法的
response.sendRedirect("wel.jsp?userName="+u);
} else {
//密码错误
response.sendRedirect("login.jsp?");
}
} else {
//用户名都错误 的
response.sendRedirect("login.jsp");
}
} catch (Exception e) {
e.printStackTrace();
}finally{
if(rs!=null){
rs.close();
}if(sm!=null){
sm.close();
}if(conn!=null){
conn.close();
}
}
%>
</body>
</html>
已经导入了驱动包，如图：
错误信息如图下：
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1117)
at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:668)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1078)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2412)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2445)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2230)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:813)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:399)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:334)
at java.sql.DriverManager.getConnection(DriverManager.java:579)
at java.sql.DriverManager.getConnection(DriverManager.java:221)
at org.apache.jsp.loginCl_jsp._jspService(loginCl_jsp.java:100)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:388)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:861)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:606)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3039)
at com.mysql.jdbc.MysqlIO.readPacket(MysqlIO.java:592)
... 34 more
请各位高人指定，小弟感激不尽，谢谢啦 try-catch里面的部分有点问题
把 if(rs.next()) 改为 while(rs.next())试试 回复 2# 21克爱情
我知道了，是端口号弄错了，mysql的应该是3306，我写到8080了，呵呵，谢谢你了。
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