db.java

一个简单的局域网网聊天程序 用Eclipse编写 数据库为SQL Server2

package com.xj.bean;

import java.sql.*;

public class DB {
	private Connection conn;
	private Statement stmt;
	private ResultSet rs;
	//打开数据库连接
	public void openConn() throws ClassNotFoundException, SQLException{
		Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
		conn=DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1433;databasename=chat","sa","");
	}
	//查询结果集
	public void openRs(String sql) throws SQLException{
		stmt=conn.createStatement();
		rs=stmt.executeQuery(sql);
	}
	//登陆时检验用户名和密码
	public String getUser(String u,String p) throws SQLException{
		stmt=conn.createStatement();
		String sql = "select * from people where username='"+u+"' and password='"+p+"'";
		rs=stmt.executeQuery(sql);
		String username="";
		while(rs.next()){
			username=rs.getString("username");
		}
		return username;
	}
	
	//用户注册
	public int regedit(String u,String p,String s,String e) throws SQLException{
		String sql="insert message values('"+u+"','"+p+"','"+s+"','"+e+"')";
		int i=0;
		stmt=conn.createStatement();
		i=stmt.executeUpdate(sql);
		return i;
		
	}
	//代结果集关闭
	public void closeRsAll() throws SQLException{
		rs.close();
		stmt.close();
		conn.close();
	}
	//不带结果集关闭
	public void closeAll() throws SQLException{
		
		stmt.close();
		conn.close();
	}
	//注册时检验用户是否重复
	public String checkUser(String u) throws SQLException{
		String sql="select * from message where username='"+u+"'";
		stmt=conn.createStatement();
		rs=stmt.executeQuery(sql);
		String user="";
		while(rs.next()){
			user=rs.getString("username");
		}
		return user;
	}
	public Connection getConn() {
		return conn;
	}
	public void setConn(Connection conn) {
		this.conn = conn;
	}
	public ResultSet getRs() {
		return rs;
	}
	public void setRs(ResultSet rs) {
		this.rs = rs;
	}
	public Statement getStmt() {
		return stmt;
	}
	public void setStmt(Statement stmt) {
		this.stmt = stmt;
	}
	
}