将jdbc常用操作封装为Sqlhelper类

Sqlhelper类

package com.sqlHelper;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class Sqlhelper {
	public  static Connection conn=null;
	
	public static Statement sta=null;
	public static PreparedStatement psta=null;
	
	public static ResultSet rs=null;
	
	public static String mysqlDriver="com.mysql.jdbc.Driver";	
	public static String mysqlDBurl="jdbc:mysql://localhost:1433/test?useSSL=false";
	
	public static String sqlserverDriver="com.microsoft.sqlserver.jdbc.SQLServerDriver";
	public static String sqlserverDBurl="jdbc:sqlserver://localhost:1433;DatabaseName=test";
	
	public static String uid="sa";
	public static String pwd="123456";
	
	// 注册驱动
		static {
			try {
				Class.forName(sqlserverDriver);
			} catch (ClassNotFoundException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
				System.out.println("注册驱动失败");
			}
		}

		// 建立连接
		public static Connection getConnection() {

			try {
				conn = DriverManager.getConnection(sqlserverDBurl, uid, pwd);
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
				System.out.println("建立连接失败");
			}
			return conn;
		}
	
	
	//select无参数查询
	public static ResultSet doQuery1(String strsql) {
		try {
			sta=conn.createStatement();
			rs = sta.executeQuery(strsql);
		} catch (SQLException e) {			
			e.printStackTrace();
		}
		return rs;		
	}
	
	//select有参数查询，常用于验证，登录
	//例如select ename,birthday,sal from emp where eno = ? and ename =?
	//arg1,arg2为select语句中的参数
	public static ResultSet doQuery2(String strsql,String arg1,String arg2) {
		try {
			//预编译语句对象
			psta =  conn.prepareStatement(strsql);			
			psta.setString(1, arg1);
			psta.setString(2, arg2);
			
			rs = psta.executeQuery();
		} catch (SQLException e) 
		{			
			e.printStackTrace();
		}
		return rs;		
	}
	
	//插入，删除，修改
		public static int doUpdate(String sql) {
			int num=0;
			Statement st=null;
			try {
				st = conn.createStatement();
				num=st.executeUpdate(sql);
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
				num=-1;
			}
			return num;
		}
		
	
	
	//关闭sql连接
	public static void closeAll(ResultSet rs, Statement st, Connection conn) {
		try {
			if (rs != null)
				rs.close();
		} catch (SQLException e) {
		} finally {
			try {
				if (st != null)
					st.close();
			} catch (SQLException e) {
			} finally {
				if (conn != null)
					try {
						conn.close();
					} catch (SQLException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
			}
		}
	}
	
	
}

引用示例1----无参数查询

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>
<%@page import="com.sqlHelper.*,java.util.*,java.sql.*"%>
  
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>引用sqlhelper</title>
</head>
<body>
	<body>
	<table border="1">
		<%!Connection conn = null;
	Statement st = null;
	ResultSet rs = null;%>
		<%
			try {

				//建立数据库连接
				conn = Sqlhelper.getConnection();
				String sql = "select top 10 * from mobile";
				rs = Sqlhelper.doQuery1(sql);
				while (rs.next()) {
		%>
		<tr>
			<td><%=rs.getInt("mobileID")%></td>
			<td><%=rs.getString("mobileName")%></td>
			<td><%=rs.getFloat("mobilePrice")%></td>
			<td><%=rs.getString("mobilePicture")%></td>
		</tr>
		<%
			}

			} catch (SQLException ex) {
				out.println(ex.getMessage());
			} finally {
				Sqlhelper.closeAll(rs, st, conn);
			}
		%>
	</table>
</body>
</html>

运行效果

引用示例2----添加数据

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>
<%@page import="com.sqlHelper.*,java.util.*,java.sql.*"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Insert title here</title>
<%!Connection conn = null;
	Statement st = null;
	ResultSet rs = null;%>
</head>
<body>
<form>
		<table>
			<tr>
				<td>dno:</td>
				<td><input type="text" name="dno" />
				</td>
			</tr>
			
			<tr>
				<td>dname:</td>
				<td><input type="text" name="dname" />
				</td>
			</tr>
			<tr>
				<td>phone:</td>
				<td><input type="text" name="phone" />
				</td>
			</tr>
			<tr>
				<td colspan="2" align="center"><input type="submit"
					name="submit" value="添加" />
				</td>
			</tr>
		</table>
	</form>
	<%
		String dno = request.getParameter("dno");
		String dname = request.getParameter("dname");
		
		String phone = request.getParameter("phone");
		if(dno==null||dname==null||phone==null)
		{
			out.print("<script>alert('未填写')</script>");
		}else{
			
		

			conn = Sqlhelper.getConnection();
			//通过拼接字符串插入数据
			String sql = "insert into test values('" + dno + "','" + dname + "','" + phone + "')";
			int num=Sqlhelper.doUpdate(sql);
			if(num>0){
				out.print("<script>alert('添加成功')</script>");
			}
			Sqlhelper.closeAll(null, st, conn);
		}
	%>


</body>
</html>

运行效果

将jdbc常用操作封装为Sqlhelper类

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