JDBC

天天搞NC财务，很多基础快忘了，现在每天复习一点点，争取盲写代码能很迅速~

BaseDao

package util;

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

public class BaseDao {
	private final static String DRIVER="org.gjt.mm.mysql.Driver";
	private final static String URL="jdbc:mysql://localhost:3306/gym";
	private final static String USERNAME="root";
	private final static String PASSWORD="admin";
	
	public static Connection getConn(){
		Connection con =null;
		try {
			Class.forName(DRIVER);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
		try {
			con = DriverManager.getConnection(URL, USERNAME, PASSWORD);
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return con;
	}

	
	public static void CloseAll(ResultSet rs,PreparedStatement ps,Connection con){
		if(rs!=null){
			try {
				rs.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			rs=null;
		}
		if(ps!=null){
			try {
				ps.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
			ps=null;
		}
		
		try {
			if(con!=null && !(con.isClosed())){
				con.close();
				con=null;
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}
}

UserImpl

package impl;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;

import util.BaseDao;
import vo.User;

public class UserImpl {
	ResultSet rs=null;
	PreparedStatement ps=null;
	Connection con=null;
	
	public ArrayList<User> SelectUser(){
		ArrayList<User> list =new ArrayList<User>();
		StringBuffer sql=new StringBuffer();
		sql.append("select id,username,password from user ");
		con=BaseDao.getConn();
		try {
			ps=con.prepareStatement(sql.toString());
			rs=ps.executeQuery();
			User u=null;
			while(rs.next()){
				u=new User();
				u.setId(rs.getInt("id"));
				u.setUsername(rs.getString("username"));
				u.setPassword(rs.getString("password"));
				list.add(u);
			}
		
		} catch (SQLException e) {
			e.printStackTrace();
		}finally{
			BaseDao.CloseAll(rs, ps, con);
		}
		return list;
	}
}

User

package vo;

public class User {
	private int id;
	private String username;
	private String password;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getUsername() {
		return username;
	}
	public void setUsername(String username) {
		this.username = username;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	
}

Test

package test;

import java.util.ArrayList;
import java.util.Iterator;

import vo.User;

import impl.UserImpl;

public class Test {
	public static void main(String[] args) {
		UserImpl ud=new UserImpl();
		ArrayList<User> list=ud.SelectUser();
		Iterator<User> iter=list.iterator();
		User u =null;
		while(iter.hasNext()){
			u=new User();
			u=iter.next();
			System.out.println(u.getId()+","+u.getUsername()+","+u.getPassword());
		}
	}
}