jsp+javabean 连接 mysql 数据库
JSP+JavaBean
1、JavaBean类
首先先澄清 这个三个都是绝对路径 没有相对路径， E://test.txt 和 E:/test.txt 是一个意思 E:\\text.txt 用这样的写法是 \\ 转义了 ‘\’ .
为什么有\\ 的写法 和 / 这样的写法呢 ，因为window 默认的是\\ 这样的写法 如果你把这样的写法放到了 linux系统下面，那么这样的写法就是错误的了，linux 系统下面只认识/ 的写法。
File file =New File("E://test.txt")、
File file =New File("E:\\test.txt")、
File file =New File("E:/test.txt")
System.getProperty("user.dir")+"/src/data/qlsxgh.xls"；我通过这个也行
//private String filepath="javabeantest\\src\\util\\JDBCconfig.properties";//error
//private String filepath="src\\util\\JDBCconfig.properties";//error
//private String filepath="javabeantest/src/util/JDBCconfig.properties";//error
//private String filepath="util\\JDBCconfig.properties";//error以上只适合本地路径，不能放到tomcat下面的哦。
//private String filepath = "/util/JDBCconfig.properties";//righttomcat andlinux only right in this way..
//private String filepath = "\\util\\JDBCconfig.properties";//error
private String filepath = "//util//JDBCconfig.properties";//righttomcat
1、显示学生信息内容
JavaBean
package com.DataBase;
import java.sql.*;
public class MyDbBean
{
private Statement stmt = null;
ResultSet rs = null;
private Connection conn = null;
private String dsn;
//构造函数
public MyDbBean() { }
//根据dsn参数，加载驱动程序，建立连接
public void getConn(String dbname, String uid, String pwd) throwsException
{
try
{
dsn ="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=" +dbname;
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();
conn = DriverManager.getConnection(dsn, uid, pwd);
}
catch (Exception ex)
{
System.err.println("aq.executeQuery: " + ex.getMessage());
}
}
//执行查询类的SQL语句，有返回集
public ResultSet executeQuery1(String sql)
{
rs = null;
try
{
stmt =conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
rs = stmt.executeQuery(sql);
}
catch(SQLException ex)
{
System.err.println("aq.executeQuery:"+ex.getMessage());
}
return rs;
}
//执行更新类的SQL语句，无返回集
public void executeUpdate2(String sql)
{
stmt = null;
rs=null;
try
{
stmt =conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
stmt.executeQuery(sql);
stmt.close();
conn.close();
}
catch(SQLException ex)
{
System.err.println("aq.executeQuery: " + ex.getMessage());
}
}
//关闭对象
public void closeStmt()
{
try{ stmt.close(); }
catch(SQLException ex)
{
System.err.println("aq.executeQuery: " + ex.getMessage());
}
}
public void closeConn()
{
try{ conn.close(); }
catch(SQLException ex)
{
System.err.println("aq.executeQuery: " + ex.getMessage());
}
}
}
“list.jsp”
<%@pagecontentType="text/html" pageEncoding="UTF-8"%>
<%@pageimport="java.sql.*" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<jsp:useBean id="testbean"scope="session" class="com.DataBase.MyDbBean" />
<html>
<head>
<metahttp-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>学籍管理系统</title>
</head>
<%! String url,sql; %>
<%! int i;%>
<body bgcolor="#ffffff">
<div align="center"><font color="#000000"size="5">学籍管理系统 </font> </div>
<table width="75%" border="1" cellspacing="1"cellpadding="1" align="center">
<tr>
<td width=16% align=center>学号</td>
<td width=16% align=center>姓名</td>
<td width=8% align=center>性别</td>
<td width=8% align=center>年龄</td>
<td width=16% align=center>籍贯</td>
<td width=12% align=center>院系</td>
<td width=12% align=center>更改</td>
<td width=12% align=center>删除</td>
</tr>
<%
//调用getConn方法与数据库建立连接
testbean.getConn("Data_Stu","sa","");
sql="select * from stuInfo";
ResultSet rs=testbean.executeQuery1(sql);//查询数据库
while(rs.next()){
%>
<tr>
<td width=16%align=center><%=rs.getString(1)%></td>
<td width=16%align=center><%=rs.getString(2)%></td>
<td width=8%align=center><%=rs.getString(3)%></td>
<tdwidth=8% align=center><%=rs.getInt(4)%></td>
<td width=16%align=center><%=rs.getString(5)%></td>
<td width=12%align=center><%=rs.getString(6)%></td>
<td width=12% align=center><ahref="change.jsp?xuehao=<%=rs.getString(1)%>">修改</a></td>
<td width=12% align=center><ahref="del.jsp?xuehao=<%=rs.getString(1)%>">删除</a></td>
</tr>
<%
}
rs.close();
testbean.closeStmt();
testbean.closeConn();
%>
</table>
<div align="center"><ahref="insert.jsp">添加新记录 </a> </div>
</body>
</html>