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JDBC的应用
003.jsp下的代码段
<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ page import="java.sql.*" %>
<%@ page import="com.mysql.jdbc.*" %>
<jsp:useBean id="myjdbc01" scope="page" class="com.zss.www.DBConn"/>
<%
request.setCharacterEncoding("utf-8");
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>
<base href="http://www.mamicode.com/">
<title>My JSP ‘001.jsp‘ starting page</title>
<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="http://www.mamicode.com/styles.css">
-->
</head>
<body>
<%
out.println("<table width=‘200‘ border=‘1‘>");
out.println("<tr>");
out.println("<th scope=‘col‘>学号</th>");
out.println("<th scope=‘col‘>班级</th>");
out.println("</tr>");
String sql="select * from information";
ResultSet rs = myjdbc01.doSelect(sql);
while (rs.next()){
out.println("<tr>");
out.println("<td>");
out.println(rs.getString(1));
out.println("</td>");
out.println("<td>");
out.println(rs.getString(2));
out.println("</td>");
out.println("</tr>");
}
out.println("</table>");
%>
</body>
</html>
DBConn.Java类下的代码
package com.zss.www;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import com.mysql.jdbc.Connection;
import com.mysql.jdbc.PreparedStatement;
public class DBConn {
private Connection conn=null;
private PreparedStatement stmt=null;
private ResultSet rs=null;
public DBConn(){
try {
String driver="com.mysql.jdbc.Driver";
String url="jdbc:mysql://localhost:3306/school";
String user="root";
String password="lbx110";
Class.forName(driver);
conn = (Connection) DriverManager.getConnection(url,user,password);
System.out.println("-------连接成功------");
} catch(ClassNotFoundException classnotfoundexception) {
classnotfoundexception.printStackTrace();
System.err.println("db: " + classnotfoundexception.getMessage());
} catch(SQLException sqlexception) {
System.err.println("db.getconn(): " + sqlexception.getMessage());
}
}
public DBConn(String driver,String url,String user,String password){
try {
//driver="com.mysql.jdbc.Driver";
//url="jdbc:mysql://localhost:3306/school";
//user="root";
//password="711109";
Class.forName(driver);
conn = (Connection) DriverManager.getConnection(url,user,password);
System.out.println("-------连接成功------");
} catch(ClassNotFoundException classnotfoundexception) {
classnotfoundexception.printStackTrace();
System.err.println("db: " + classnotfoundexception.getMessage());
} catch(SQLException sqlexception) {
System.err.println("db.getconn(): " + sqlexception.getMessage());
}
}
public void doInsert(String sql) {
try {
stmt = (PreparedStatement)conn.prepareStatement(sql);
int i = stmt.executeUpdate(sql);
} catch(SQLException sqlexception) {
System.err.println("db.executeInsert:" + sqlexception.getMessage());
}finally{
}
}
public void doDelete(String sql) {
try {
stmt = (PreparedStatement)conn.prepareStatement(sql);
int i = stmt.executeUpdate(sql);
} catch(SQLException sqlexception) {
System.err.println("db.executeDelete:" + sqlexception.getMessage());
}
}
public void doUpdate(String sql) {
try {
stmt = (PreparedStatement)conn.prepareStatement(sql);
int i = stmt.executeUpdate(sql);
} catch(SQLException sqlexception) {
System.err.println("db.executeUpdate:" + sqlexception.getMessage());
}
}
public ResultSet doSelect(String sql) {
try {
stmt = (PreparedStatement)conn.prepareStatement(sql);
rs = stmt.executeQuery(sql);
System.out.println("取得结果集");
} catch(SQLException sqlexception) {
System.err.println("db.executeQuery: " + sqlexception.getMessage());
}
return rs;
}
public void close(ResultSet rs) throws SQLException, Exception {
if (rs != null) {
rs.close();
rs = null;
}
if (stmt != null) {
stmt.close();
stmt = null;
}
if (conn != null) {
conn.close();
conn = null;
}
}
public void close() throws SQLException, Exception {
if (stmt != null) {
stmt.close();
stmt = null;
}
if (conn != null) {
conn.close();
conn = null;
}
}
public static void main(String []args) throws Exception {
DBConn db=new DBConn();
ResultSet rs=db.doSelect("select * from dbuser where userNAME=‘lin‘");
try {
while(rs.next()) {
System.out.println(rs.getString(1));
System.out.println(rs.getString(2));
System.out.println(rs.getString(3));
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
rs.close();
db.close();
}
}
JDBC的应用