userdao.java

简单的用户名和密码登录验证系统

/**
 * 
 */
package user.dao;

import java.sql.SQLException;

import com.mysql.jdbc.PreparedStatement;
import com.mysql.jdbc.ResultSet;

import user.entity.User;

/**
 * @author Administrator
 *
 */
public class UserDAO {
	public User findUserByUsernamePassword(User user){
		try{//注册驱动
			Class.forName("com.mysql.jdbc.Driver");
		}catch (ClassNotFoundException e){
			e.printStackTrace();
		}
		java.sql.Connection conn = null;
		java.sql.PreparedStatement pstmt = null;
		ResultSet rs = null;
	    try{//获取数据库的连接
	    	 conn = java.sql.DriverManager.getConnection(
	    			 "jdbc:mysql://localhost/test?useUnicode=true&characterEncoding=GBK","root","11");
	    	 pstmt = conn.prepareStatement("select * from myuser where username = ? and password = ?");
	    	 pstmt.setString(1, user.getUsername());
	    	 pstmt.setString(2, user.getPassword());
	    	 if(rs!=null && rs.next()){
	    		 user.setId(rs.getInt("id"));
	    		 return user;
	    	 }
	    	 
	    }catch(SQLException e){
	    	e.printStackTrace();
	    }finally{
	    	try {
				pstmt.close();
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			try {
				conn.close();
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
	    }
		return user;
	}
}