用Java编写小程序

package com.erha.dao;

import com.erha.model.Music;

public interface IMusic {
    void insertMusic(Music newMusic) throws Exception;  // 添加音乐的方法

    void deleteMusic(int id) throws Exception;  // 删除音乐的方法

    void updateMusic(int id,Music modMusic) throws Exception;  // 更新音乐的方法

    void selectByID(int id) throws Exception;   // 根据id查询音乐

    void selectAllMusic() throws  Exception;// 查询全部音乐
}

package com.erha.dao;

import com.erha.model.User;

public interface IUser {
    void insertUser(User newUser) throws Exception;  // 添加用户的方法

    void deleteUser(int id) throws Exception;  // 删除用户的方法

    void updateUser(int id,User modUser) throws Exception;  // 更新用户的方法

    void selectByID(int id) throws Exception;   // 根据id查询用户

    void selectAllUser() throws  Exception;// 查询全部用户
}

package com.erha.daoimpl;

import com.erha.dao.IMusic;
import com.erha.model.Music;
import com.erha.util.DBUtil;

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

public class MusicDao implements IMusic {

    DBUtil db = new DBUtil();

    @Override
    public void insertMusic(Music newMusic) throws Exception { // 增加DVD方法的实现
        // 将音乐添加到数据库中进行保存
        Connection conn = db.getConn();
        PreparedStatement pstm = null;
        String sql_insert = "insert into dvd(DVD,type) values(?,?)";
        pstm = conn.prepareStatement(sql_insert);
        pstm.setString(1, newMusic.getName());
        pstm.setString(2, newMusic.getType());

        int row = pstm.executeUpdate();
        System.out.println("添加成功," + row + "行受到影响.");
        db.closeConn(null, pstm, conn);
    }

    @Override
    public void deleteMusic(int id) throws Exception { // 根据id删除音乐方法的实现
        // 根据音乐主键编号删除音乐
        selectAllMusic();


        Connection conn = db.getConn();
        PreparedStatement pstm = null;
        String sql_delete = "delete from dvd where id=?";
        pstm = conn.prepareStatement(sql_delete);
        pstm.setInt(1, id);

        int row = pstm.executeUpdate();
        System.out.println("删除成功," + row + "行受到影响");
        db.closeConn(null, pstm, conn);

    }

    @Override
    public void updateMusic(int id,Music modMusic) throws Exception {  // 根据id修改音乐方法的实现
        // 根据音乐主键编号修改音乐
        Connection conn = db.getConn();
        PreparedStatement pstm = null;
        String sql_update = "update DVD set DVD=?,type=? where id=?";

        pstm = conn.prepareStatement(sql_update);
        pstm.setString(1,modMusic.getName());
        pstm.setString(2,modMusic.getType());
        pstm.setInt(3,id);

        int row = pstm.executeUpdate();
        System.out.println("更新成功,"+row+"行受到影响");

        db.closeConn(null, pstm, conn);
    }

    @Override
    public void selectByID(int id) throws Exception {  // 根据id单查音乐方法的实现
        // 根据音乐主键编号查询音乐信息
        Connection conn = db.getConn();
        PreparedStatement pstm = null;
        ResultSet rs = null;
        String sql_selectById = "select * from DVD where id=?";

        pstm = conn.prepareStatement(sql_selectById);
        pstm.setInt(1, id);

        rs = pstm.executeQuery();
        System.out.println("查询成功,信息如下：");
        System.out.println("DVD编号\t\t" + "DVD名称\t\t\t" + "DVD类型");
        while(rs.next()){
            System.out.println(rs.getInt("id")+"\t\t\t"+rs.getString("DVD")+"\t\t\t"+rs.getString("type"));
        }
        db.closeConn(rs, pstm, conn);
    }
    public void selectByDVD(String DVD) throws Exception {  // 根据id单查音乐方法的实现
        // 根据音乐主键编号查询音乐信息
        Connection conn = db.getConn();
        PreparedStatement pstm = null;
        ResultSet rs = null;
        String sql_selectById = "select * from DVD where DVD=?";

        pstm = conn.prepareStatement(sql_selectById);
        pstm.setString(1, DVD);

        rs = pstm.executeQuery();
        System.out.println("查询成功,信息如下：");
        System.out.println("DVD编号\t\t" + "DVD名称\t\t\t" + "DVD类型");
        while(rs.next()){
            System.out.println(rs.getInt("id")+"\t\t\t"+rs.getString("DVD")+"\t\t\t"+rs.getString("type"));
        }
        db.closeConn(rs, pstm, conn);
    }
    public void selectBytype(String type) throws Exception {  // 根据id单查音乐方法的实现
        // 根据音乐主键编号查询音乐信息
        Connection conn = db.getConn();
        PreparedStatement pstm = null;
        ResultSet rs = null;
        String sql_selectById = "select * from DVD where type=?";

        pstm = conn.prepareStatement(sql_selectById);
        pstm.setString(1, type);

        rs = pstm.executeQuery();
        System.out.println("查询成功,信息如下：");
        System.out.println("DVD编号\t\t" + "DVD名称\t\t\t" + "DVD类型");
        while(rs.next()){
            System.out.println(rs.getInt("id")+"\t\t\t"+rs.getString("DVD")+"\t\t\t"+rs.getString("type"));
        }
        db.closeConn(rs, pstm, conn);
    }
    @Override
    public void selectAllMusic() throws Exception {
        // 查询所有的音乐信息
        Connection conn = db.getConn();
        PreparedStatement pstm = null;
        ResultSet rs = null;
        String sql_selectAll = "select * from DVD";

        pstm = conn.prepareStatement(sql_selectAll);

        rs = pstm.executeQuery();
        System.out.println("所有DVD信息如下：");
        System.out.println("DVD编号\t\t" + "DVD名称\t\t\t" + "DVD类型");
        while(rs.next()){
            System.out.println(rs.getInt("id")+"\t\t\t"+rs.getString("DVD")+"\t\t\t"+rs.getString("type"));
        }
        db.closeConn(rs, pstm, conn);
    }
}

package com.erha.daoimpl;

import com.erha.dao.IUser;
import com.erha.model.User;
import com.erha.util.DBUtil;

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

public class UserDao implements IUser {
    DBUtil db = new DBUtil();
    private Connection conn;

    @Override
    public void insertUser(User newUser) throws Exception {
        // 将用户信息添加到后台数据库表中
        Connection conn = db.getConn();