package cn.hu3.com;
import cn.hu1.com.JdbcUtils;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
public class DemoStudent {
    public static void main(String[] args) throws SQLException {
        // 创建对象
        Connection conn = JdbcUtils.getConnection();
        PreparedStatement ps = conn.prepareStatement("select * FROM emppme");
        // 设置参数
        ResultSet rs = ps.executeQuery();
        ArrayList<emppme> al = new ArrayList<emppme>();
        while(rs.next()){
// 把记录封装成对象
            emppme em = new emppme();
            em.setId(rs.getInt("id"));
            em.setUname(rs.getString("uname"));
            em.setGender(rs.getBoolean("gender"));
// 把对象添加到集合中
            al.add(em);
        }
        JdbcUtils.close(rs,ps,conn);
//遍历集合
        for(emppme ep:al){
            System.out.println(ep);
        }
    }
}

package cn.hu3.com;
public class emppme {
    private  int id;
    private  String uname;
    private  boolean gender;
    @Override
    public String toString() {
        return "emppme{" +
                "id=" + id +
                ", uname='" + uname + '\'' +
                ", gender=" + gender +
                '}';
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getUname() {
        return uname;
    }

    public void setUname(String uname) {
        this.uname = uname;
    }

    public boolean isGender() {
        return gender;
    }

    public void setGender(boolean gender) {
        this.gender = gender;
    }
}

package cn.hu1.com;

import java.io.FileReader;
import java.io.IOException;
import java.net.URL;
import java.sql.*;
import java.util.Properties;

/**
 *  JDBC工具类
 * */
public class JdbcUtils {
    private static String url;
    private static String user;
    private static String password;
    private static String driver;
    // 文件的读取  读取一次拿到所有值   使用静态代码块
    static{
        try {
            // 读取资源文件  获取值   创建Properties 集合类
            Properties pro = new Properties();
            // 获取src的路径----》ClassLoader()    类加载器
            ClassLoader classLoader = JdbcUtils.class.getClassLoader();
            URL res = classLoader.getResource("jdbc.properties");
            String path = res.getPath();
            pro.load(new FileReader(path));
            url=pro.getProperty("url");
            user=pro.getProperty("user");
            password=pro.getProperty("password");
            driver=pro.getProperty("driver");

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    //获取链接对象
    public static Connection getConnection() throws SQLException {
        return DriverManager.getConnection(url,user,password);
    }
    //释放资源
    public static void close(Statement stmt,Connection conn){
        if(stmt!=null){
            try {
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if(conn!=null){
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
    //释放资源
    public static void close(ResultSet rs,Statement stmt, Connection conn){
        if(rs!=null){
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if(stmt!=null){
            try {
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if(conn!=null){
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

url=jdbc:mysql:///qy97
user=root
password=root
driver=com.mysql.jdbc.Driver