DAO模式

Posted 2020-11-21 xhddbky

JDBC封装

　为什么进行JDBC封装

　　

　　

　实现JDBC封装

　　

　　

　　

　　

　　

　　

　　

　DAO模式的组成

　　

　　

package cn.jbit.epet.entity;

import java.util.Date;

public class Pet {
    private int id; // 宠物id
    private int masterId; // 主人id
    private String name; // 昵称
    private int typeId; // 类型id
    private int health; // 健康值
    private int love; // 亲密度
    private Date adoptTime; // 领养时间
    private String status; // 状态

    public Pet() {
    }

    public Pet(int id, int masterId, String name, int typeId, int health,
            int love, Date adoptTime, String status) {
        super();
        this.id = id;
        this.masterId = masterId;
        this.name = name;
        this.typeId = typeId;
        this.health = health;
        this.love = love;
        this.adoptTime = adoptTime;
        this.status = status;
    }

    public int getId() {
        return id;
    }

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

    public int getMasterId() {
        return masterId;
    }

    public void setMasterId(int masterId) {
        this.masterId = masterId;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getTypeId() {
        return typeId;
    }

    public void setTypeId(int typeId) {
        this.typeId = typeId;
    }

    public int getHealth() {
        return health;
    }

    public void setHealth(int health) {
        this.health = health;
    }

    public int getLove() {
        return love;
    }

    public void setLove(int love) {
        this.love = love;
    }

    public Date getAdoptTime() {
        return adoptTime;
    }

    public void setAdoptTime(Date adoptTime) {
        this.adoptTime = adoptTime;
    }

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }
}

实体类

package cn.jbit.epet.dao;

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

public class BaseDao {
    private String driver = "com.mysql.jdbc.Driver"; // 数据库驱动字符串
    private String url = "jdbc:mysql://localhost:3306/epet"; // 数据库连接字符串
    private String user = "epetadmin"; // 数据库用户名
    private String password = "0000"; // 数据库密码
    Connection conn = null;

    // 1.打开数据库
    public Connection getConnection() {
        try {
            Class.forName(driver);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        try {
            conn = DriverManager.getConnection(url, user, password);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return conn;
    }

    // 2.关闭所有资源
    public void closeAll(Connection conn, PreparedStatement stmt, ResultSet rs) {
        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();
            }
        }
    }

    // 3.增、删、改通用方法
    public int executeUpdate(String sql, Object[] param) {
        int num = 0; // 影响行数
        conn = this.getConnection();
        PreparedStatement stmt = null;
        try {
            stmt = conn.prepareStatement(sql);
            // 为参数赋值
            if (param != null) {
                for (int i = 0; i < param.length; i++) {
                    stmt.setObject(i + 1, param[i]);
                }
            }
            // 执行sql语句
            num = stmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            this.closeAll(conn, stmt, null);
        }
        return num;
    }
}

数据库工具类

package cn.jbit.epet.dao;

import java.util.List;

import cn.jbit.epet.entity.Pet;

public interface PetDao {
    int save(Pet pet);

    int del(Pet pet);

    int update(Pet pet);

    Pet getByName(String name);

    List<Pet> findByName(String name);

    List<Pet> findByType(String type);
}

DAO接口

package cn.jbit.epet.dao.impl;

import java.util.List;

import cn.jbit.epet.dao.BaseDao;
import cn.jbit.epet.dao.PetDao;
import cn.jbit.epet.entity.Pet;

public class PetDaoMySQLImpl extends BaseDao implements PetDao {

    @Override
    public int save(Pet pet) {
        return 0;
    }

    @Override
    public int del(Pet pet) {
        return 0;
    }

    @Override
    public int update(Pet pet) {
        String sql = "update dog set status=0 where id=?";
        Object[] param = { pet.getId() };
        int result = this.executeUpdate(sql, param);
        return result;
    }

    @Override
    public Pet getByName(String name) {
        return null;
    }

    @Override
    public List<Pet> findByName(String name) {
        return null;
    }

    @Override
    public List<Pet> findByType(String type) {
        return null;
    }

}

DAO实现类

package cn.jbit.epet.manager;

import cn.jbit.epet.dao.PetDao;
import cn.jbit.epet.dao.impl.PetDaoMySQLImpl;
import cn.jbit.epet.entity.Pet;

public class Test {
    public static void main(String[] args) {
        PetDao petDao = new PetDaoMySQLImpl();
        Pet pet = new Pet();
        pet.setId(1);
        int result = petDao.update(pet);
        if (result > 0) {
            System.out.println("狗狗信息更新成功！");
        } else {
            System.out.println("狗狗信息更新失败！");
        }
    }
}

测试类

Properties类