zoukankan      html  css  js  c++  java
  • 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="<%=basePath%>">

    <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="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();
    }
    }

  • 相关阅读:
    Python 如何隐藏属性
    Python 多态
    Python 绑定方法与非绑定方法
    Python 类的组合
    ASP.NET CS文件中输出JavaScript脚本的3种方法以及区别
    JQuery中$之选择器用法介绍
    C#语言之“string格式的日期时间字符串转为DateTime类型”的方法
    .net中response.redirect sever.execute server.transfer 三种页面跳转的方法
    safari,chrome中的window.history.go(-1) history.back()
    onbeforeunload与onunload事件
  • 原文地址:https://www.cnblogs.com/bgd150809336/p/6668037.html
Copyright © 2011-2022 走看看