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【数据库连接】——节选自培训

2022-07-22 18:12:00 【terrific51】

本篇笔记主要是关于用java连接mysql数据库，实现对数据库的增删改查。

如图为该实验的大致框架：
在这里插入图片描述
运行结果：在这里插入图片描述
各部分代码及解释：

1. DBconnector

package Dao;

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

public class DBconnector {
//java连接数据库
	private static final String DBDRIVER = "com.mysql.cj.jdbc.Driver"; // 驱动串
	private static final String DBURL = "jdbc:mysql://localhost:3306/grate";// 连接URL
	private static final String DBUSER = "root"; // 用户名
	private static final String DBPASSWORD = "123456"; // 密码
	public static Connection getConnection() {
		Connection conn = null;
		//判断异常
		try {
			Class.forName(DBDRIVER);//加载驱动
			//获取连接
			conn = (Connection) DriverManager.getConnection(DBURL, DBUSER, DBPASSWORD);
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			System.out.println("驱动加载异常");
		}
		catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			System.out.println("连接异常");
		}
		return conn;
	}

}

2. Add_users(增)

package Dao_users;


import Dao.DBconnector;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class Add_users extends JDialog implements ActionListener{
	/*
	 * 实现序列化接口,用于跨版本翻译
	 */
	private static final long SerialVersionUID =1L;

	private JPanel jp1,jp2;	//局面分布面板。

	JLabel JL=new JLabel("添加学生信息",JLabel.CENTER);//创建主标签

//JLabel     JTextField
	JLabel JLSno= new JLabel("学号:");
	JTextField JTSno= new JTextField();

	JLabel JLSname= new JLabel("姓名:");
	JTextField JTSname= new JTextField();

	JLabel JLSsex= new JLabel("性别:");
	JTextField JTSsex= new JTextField();

	JLabel JLSage= new JLabel("年龄:");
	JTextField JTSage= new JTextField();

	JLabel JLSdept= new JLabel("学院:");
	JTextField JTSdept= new JTextField();

	// 三个按钮
	JButton JB1=new JButton("添加");
	JButton JB2=new JButton("重置");
	JButton JB3=new JButton("退出");
	
	//图片
	ImageIcon image=new ImageIcon("D:\\小窝海绵宝宝.png");
	JLabel label=new JLabel(image);

	// 创建连接数据方法
	String sql="";
	//创建构造方法
	public Add_users()
	{
		Container c = this.getContentPane();
		jp1 = new JPanel();

		// 设置窗口大小
		this.setSize(700,450);
		this.setLocationRelativeTo(null);
		this.setVisible(true);

		// 添加
		this.setTitle("添加学生信息");
		this.setLayout(null);//设置窗口布局管理器为null,用setBounds()方法设置组件位置

		//JL.setFont(new Font("宋体",Font.PLAIN,30));
		//JL.setBounds(100,40,200,40);
		//jp1.add(JL);

		//布局
		
		JLSno.setFont(new Font("黑体", Font.PLAIN, 30));
		JTSno.setFont(new Font("黑体", Font.PLAIN, 30));
		JLSno.setBounds(50,50,100,30);
		this.add(JLSno);
		JTSno.setBounds(150,50,150,30);
		this.add(JTSno);

		JLSname.setFont(new Font("黑体", Font.PLAIN, 30));
		JTSname.setFont(new Font("黑体", Font.PLAIN, 30));
		JLSname.setBounds(370,50,100,30);
		this.add(JLSname);
		JTSname.setBounds(470,50,150,30);
		this.add(JTSname);

		JLSsex.setFont(new Font("黑体", Font.PLAIN, 30));
		JTSsex.setFont(new Font("黑体", Font.PLAIN, 30));
		JLSsex.setBounds(50,125,100,30);
		this.add(JLSsex);
		JTSsex.setBounds(150,125,150,30);
		this.add(JTSsex);

		JLSage.setFont(new Font("黑体", Font.PLAIN, 30));
		JTSage.setFont(new Font("黑体", Font.PLAIN, 30));
		JLSage.setBounds(350,125,120,30);
		this.add(JLSage);
		JTSage.setBounds(470,125,150,30);
		this.add(JTSage);

		JLSdept.setFont(new Font("黑体", Font.PLAIN, 30));
		JTSdept.setFont(new Font("黑体", Font.PLAIN, 30));
		JLSdept.setBounds(200,200,100,30);
		this.add(JLSdept);
		JTSdept.setBounds(300,200,150,30);
		this.add(JTSdept);

		// 三个按钮
		JB1.setFont(new Font("黑体", Font.PLAIN, 30));
		JB2.setFont(new Font("黑体", Font.PLAIN, 30));
		JB3.setFont(new Font("黑体", Font.PLAIN, 30));
		JB1.setBounds(80,320,120,40);
		this.add(JB1);
		JB1.addActionListener(this);
		JB2.setBounds(280,320,120,40);
		this.add(JB2);
		JB2.addActionListener(this);
		JB3.setBounds(480,320,120,40);
		this.add(JB3);
		JB3.addActionListener(this);

		//图片
		this.setLayout(null);
		this.add(label);
		label.setBounds(0,0,700,450);

		addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent e)
			{
				dispose();
			}
		});

	}
	public void actionPerformed(ActionEvent e) {
		if(e.getSource()==JB1)
		{
			users users=new users();//实例化对象
			users.setSno(JTSno.getText());
			users.setSname(JTSname.getText());
			users.setSsex(JTSsex.getText());
			users.setSage(JTSage.getText());
			users.setSdept(JTSdept.getText());

			sql="select * from student where Sno='"+users.getSno()+"'";
			//sql="select * from student where Sno=123";
			//连接数据库
			DBconnector conn=new DBconnector();
			Connection con=conn.getConnection();
			//创建Statement对象
			try {
				Statement stmt=(Statement) con.createStatement();
				ResultSet rs= (ResultSet) stmt.executeQuery(sql);
				System.out.println("OK!");
				if(rs.next())
				{
					JOptionPane.showMessageDialog(null,"该学号已经存在");
					rs.close();
				}
				else{
					sql="insert into student(Sno,Sname,Ssex,Sage,Sdept) "
							+ "values('"+users.getSno()+"','"+users.getSname()+"','"+users.getSsex()+"','"+users.getSage()+"','"+
							users.getSdept()+"');";//  字符串类型的放到sql语句里统一一个双引号和一个单引号。注意分号。
					int i=stmt.executeUpdate(sql);
					if(i>0)
					{
						JOptionPane.showMessageDialog(null,"添加成功");
					}
					else{
						JOptionPane.showMessageDialog(null,"添加失败");
					}
				}
			} catch (SQLException e1) {
				e1.printStackTrace();
			}
		}
		else if(e.getSource()==JB2)
		{
			JTSno.setText(null);
			JTSname.setText(null);
			JTSsex.setText(null);
			JTSage.setText(null);
			JTSdept.setText(null);
		}
		else if(e.getSource()==JB3)
		{
			this.setVisible(false);
		}

	}
	public static void main(String[] args) {
		new Add_users();
	}
}

3. Delete_users(删)

//根据学号删除

package Dao_users;

import Dao.DBconnector;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class Delete_users extends JFrame implements ActionListener{

	private static final long serialVersionUID=1L;

	ImageIcon image=new ImageIcon("D:\\小窝海绵宝宝.png");
	JLabel label=new JLabel(image);
	// 标题
	JLabel JL=new JLabel("删除基本信息",JLabel.CENTER);
	//
	JLabel JLSno= new JLabel("学号:");
	JTextField JTSno= new JTextField();


	JButton JB1=new JButton("删除");
	JButton JB2=new JButton("重置");
	JButton JB3=new JButton("退出");

	String sql="";
	//定义构造函数
	public Delete_users()
	{
		//设置窗口
		this.setTitle("删除学生信息");
		this.setSize(700,450);
		this.setLocationRelativeTo(null);
		this.setLayout(null);
		this.setVisible(true);

		this.setLayout(null);
		this.add(label);
		label.setBounds(0,0,700,260);

		// 设置题目信息
		JL.setForeground(Color.red);
		JL.setFont(new Font("宋体",Font.PLAIN,19));
		JL.setBounds(150,30,200,40);
		this.add(JL);

		//
		JLSno.setFont(new Font("黑体", Font.PLAIN, 30));
		JTSno.setFont(new Font("黑体", Font.PLAIN, 30));
		JLSno.setBounds(200,280,100,30);
		this.add(JLSno);
		JTSno.setBounds(300,280,150,30);
		this.add(JTSno);

		// 三个按钮
		JB1.setFont(new Font("黑体", Font.PLAIN, 30));
		JB2.setFont(new Font("黑体", Font.PLAIN, 30));
		JB3.setFont(new Font("黑体", Font.PLAIN, 30));
		JB1.setBounds(80,340,120,40);
		this.add(JB1);
		JB1.addActionListener(this);
		JB2.setBounds(280,340,120,40);
		this.add(JB2);
		JB2.addActionListener(this);
		JB3.setBounds(480,340,120,40);
		this.add(JB3);
		JB3.addActionListener(this);

		addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent e)
			{
				dispose();
			}
		});
	}

	public void actionPerformed(ActionEvent e) {
		if(e.getSource()==JB1)
		{
			users users=new users();//实例化对象
			users.setSno(JTSno.getText());

			sql="select * from student where Sno="+users.getSno();
			DBconnector conn=new DBconnector();
			Connection con=conn.getConnection();
			try {
				Statement stmt=(Statement) con.createStatement();
				ResultSet rs=(ResultSet) stmt.executeQuery(sql);
				if(rs.next())//如果查询结果存在
				{
					sql="delete from student where Sno="+users.getSno();
					int n=stmt.executeUpdate(sql);//更新
					if(n>0)JOptionPane.showMessageDialog(null, "删除成功");
					else JOptionPane.showMessageDialog(null, "删除失败");
				}
				else
				{
					rs.close();
					JOptionPane.showMessageDialog(null, "此学生不存在");
				}
			} catch (SQLException e1) {
				e1.printStackTrace();
			}
		}
		else if(e.getSource()==JB2)
		{
			JTSno.setText(null);
		}
		else
		{
			this.setVisible(false);//隐藏当前窗口
		}

	}
	public static void main(String[] args) {
		new Delete_users();
	}
}

4. Get_users(查)

package Dao_users;

import Dao.DBconnector;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Vector;

public class Get_users extends JFrame{
	private static final long serialVersionUID = 1L;

	//存放所有信息
	Vector all=new Vector();
	//存储表头信息向量
	Vector tablehead=new Vector();

	JLabel JL=new JLabel("查询学生基本信息",JLabel.CENTER);
	JScrollPane jsl=new JScrollPane();//设置滚动面板

	JLabel JLSno= new JLabel("学号:");
	JTextField JTSno= new JTextField();

	JLabel JLSname= new JLabel("姓名:");
	JTextField JTSname= new JTextField();

	JLabel JLSsex= new JLabel("性别:");
	JTextField JTSsex= new JTextField();

	JLabel JLSage= new JLabel("年龄:");
	JTextField JTSage= new JTextField();

	JLabel JLSdept= new JLabel("学院:");
	JTextField JTSdept= new JTextField();

	// 定义构造方法
	// 建立数据库连接
	String sql="";
	public Get_users()
	{

		//this.setLayout(null);
		//this.add(label);
		//label.setBounds(100,100,1000,700);

		// 数据库查询语句
		sql="select * from student;";
		//连接数据库
		DBconnector conn=new DBconnector();
		Connection con=(Connection) conn.getConnection();
		ResultSet rs=null;
		Statement stmt;
		try {
			stmt = (Statement) con.createStatement();
			rs=(ResultSet) stmt.executeQuery(sql);

			tablehead.add("学号");
			tablehead.add("名字");
			tablehead.add("性别");
			tablehead.add("年龄");
			tablehead.add("学院");


			while(rs.next())
			{
				// 建立对象
				users users=new users();
				users.setSno(rs.getString("Sno"));
				users.setSname(rs.getString("Sname"));
				users.setSsex(rs.getString("Ssex"));
				users.setSage(rs.getString("Sage"));
				users.setSdept(rs.getString("Sdept"));



				Vector vc=new Vector();

				vc.add(users.getSno());
				vc.add(users.getSname());
				vc.add(users.getSsex());
				vc.add(users.getSage());
				vc.add(users.getSdept());
				System.out.println(vc);


				// 全部放入vc集合中
				all.add(vc);
			}


			JTable JT=new JTable(all,tablehead);


			JT.setRowHeight(20);//设置表格行高
			JT.setEnabled(false);//设置表格不可编辑
			jsl.setViewportView(JT);//显示在滚动面板


			this.add(jsl,BorderLayout.NORTH);
			//this.add(JL);添加
			this.setTitle("查询所有学生信息");
			this.setSize(700,450);
			this.setLocationRelativeTo(null);
			this.setVisible(true);


		} catch (SQLException e1) {
			e1.printStackTrace();
		}

		addWindowListener(new WindowAdapter() {//设置窗口监听器
			@SuppressWarnings("unused")
			public void windowsClosing(WindowEvent e)
			{
				dispose();
			}
		});
	}
	public void actionPerformed(ActionEvent e) {


	}


	public static void main(String[] args) {
		new Get_users();
	}
}

5. Update_users(改)

package Dao_users;

import Dao.DBconnector;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class Update_users extends JFrame implements ActionListener {

	private static final long SerialVersionUID =1L;

	JLabel JLSno= new JLabel("学号:");
	JTextField JTSno= new JTextField();

	JLabel JLSname= new JLabel("姓名:");
	JTextField JTSname= new JTextField();

	JLabel JLSsex= new JLabel("性别:");
	JTextField JTSsex= new JTextField();

	JLabel JLSage= new JLabel("年龄:");
	JTextField JTSage= new JTextField();

	JLabel JLSdept= new JLabel("学院:");
	JTextField JTSdept= new JTextField();

	// 三个按钮
	JButton JB1=new JButton("添加");
	JButton JB2=new JButton("重置");
	JButton JB3=new JButton("退出");
	ImageIcon image=new ImageIcon("D:\\小窝海绵宝宝.png");
	JLabel label=new JLabel(image);

	// 创建数据库语句对象
	String sql="";
	public Update_users()
	{
		// 设置窗口位置及大小，并添加标题
		this.setSize(700,450);
		this.setLocationRelativeTo(null);
		this.setVisible(true);
		this.setTitle("修改学生信息");
		// 设置窗口管理器为空
		this.setLayout(null);

		//
		JLSno.setFont(new Font("黑体", Font.PLAIN, 30));
		JTSno.setFont(new Font("黑体", Font.PLAIN, 30));
		JLSno.setBounds(50,50,100,30);
		this.add(JLSno);
		JTSno.setBounds(150,50,150,30);
		this.add(JTSno);

		//
		JLSname.setFont(new Font("黑体", Font.PLAIN, 30));
		JTSname.setFont(new Font("黑体", Font.PLAIN, 30));
		JLSname.setBounds(370,50,100,30);
		this.add(JLSname);
		JTSname.setBounds(470,50,150,30);
		this.add(JTSname);



		//
		JLSsex.setFont(new Font("黑体", Font.PLAIN, 30));
		JTSsex.setFont(new Font("黑体", Font.PLAIN, 30));
		JLSsex.setBounds(50,125,100,30);
		this.add(JLSsex);
		JTSsex.setBounds(150,125,150,30);
		this.add(JTSsex);

		//
		JLSage.setFont(new Font("黑体", Font.PLAIN, 30));
		JTSage.setFont(new Font("黑体", Font.PLAIN, 30));
		JLSage.setBounds(350,125,120,30);
		this.add(JLSage);
		JTSage.setBounds(470,125,150,30);
		this.add(JTSage);

		JLSdept.setFont(new Font("黑体", Font.PLAIN, 30));
		JTSdept.setFont(new Font("黑体", Font.PLAIN, 30));
		JLSdept.setBounds(200,200,100,30);
		this.add(JLSdept);
		JTSdept.setBounds(300,200,150,30);
		this.add(JTSdept);

		// 三个按钮
		JB1.setFont(new Font("黑体", Font.PLAIN, 30));
		JB2.setFont(new Font("黑体", Font.PLAIN, 30));
		JB3.setFont(new Font("黑体", Font.PLAIN, 30));
		JB1.setBounds(80,320,120,40);
		this.add(JB1);
		JB1.addActionListener(this);
		JB2.setBounds(280,320,120,40);
		this.add(JB2);
		JB2.addActionListener(this);
		JB3.setBounds(480,320,120,40);
		this.add(JB3);
		JB3.addActionListener(this);

		this.setLayout(null);
		this.add(label);
		label.setBounds(0,0,700,450);


		addWindowListener(new WindowAdapter() {
			public void windowClosing(WindowEvent e)
			{
				dispose();
			}
		});
	}
	// 按钮事件
	public void actionPerformed(ActionEvent e) {
		if(e.getSource()==JB1)
		{
			users users=new users();//实例化对象
			users.setSno(JTSno.getText());
			users.setSname(JTSname.getText());
			users.setSsex(JTSsex.getText());
			users.setSage(JTSage.getText());
			users.setSdept(JTSdept.getText());
			// 数据库查询语句
			sql="select * from student where Sno="+users.getSno();
			//连接数据库
			DBconnector conn=new DBconnector();
			Connection con=conn.getConnection();
			try {
				Statement stmt=(Statement) con.createStatement();
				ResultSet rs=(ResultSet) stmt.executeQuery(sql);
				if(rs.next())
				{
					sql="update student set Sname='"+users.getSname()+"',Ssex='"+users.getSsex()+"',Sage='"+
							users.getSage()+"',Sdept='"+users.getSdept()+"' where Sno ="+users.getSno();


					int n=stmt.executeUpdate(sql);
					if(n>0)
					{
						JOptionPane.showMessageDialog(null,"更新成功");
					}
					else
					{
						JOptionPane.showMessageDialog(null, "更新失败");
					}

				}
				else
				{
					JOptionPane.showMessageDialog(null, "此学号不存在");
				}
			} catch (SQLException e1) {
				e1.printStackTrace();
			}
		}
		else if(e.getSource()==JB2)
		{
			JTSno.setText(null);
			JTSname.setText(null);
			JTSsex.setText(null);
			JTSage.setText(null);
			JTSdept.setText(null);
		}
		else if(e.getSource()==JB3)
		{
			this.setVisible(false);
		}


	}

	public static void main(String[] args) {

		new Update_users();
	}

}

6. users

package Dao_users;

public class users {
//进行各个数据的传入
	public String getSno() {
		return Sno;
	}

	public void setSno(String sno) {
		Sno = sno;
	}

	public String getSname() {
		return Sname;
	}

	public void setSname(String sname) {
		Sname = sname;
	}

	public String getSsex() {
		return Ssex;
	}

	public void setSsex(String ssex) {
		Ssex = ssex;
	}

	public String getSage() {
		return Sage;
	}

	public void setSage(String sage) {
		Sage = sage;
	}

	public String getSdept() {
		return Sdept;
	}

	public void setSdept(String sdept) {
		Sdept = sdept;
	}

//私有化
	// 学号
	private String Sno;
	// 姓名
	private String Sname;
	// 性别
	private String Ssex;
	// 年龄
	private String Sage;
	// 学院
	private String Sdept;
	public users() {
	}

}

//主界面代码

7. employee

package Main;

import Dao_users.Add_users;
import Dao_users.Delete_users;
import Dao_users.Get_users;
import Dao_users.Update_users;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

public class employee extends JFrame implements ActionListener{


	// 创建四个按钮
	private static final long serialVersionUID = 1L;
	JButton JB1=new JButton();
	JButton JB2=new JButton();
	JButton JB3=new JButton();
	JButton JB4=new JButton();

	ImageIcon image=new ImageIcon("D:\\小窝海绵宝宝.png"); //插入界面显示的图片
	JLabel label=new JLabel(image);
	String name1 = null;
	public employee(String name)   //构造方法添加内容
	{
		// 标题
		name1 = name;
		this.setTitle("学生界面管理");
		this.setBackground(Color.DARK_GRAY); //界面字体颜色
		this.setLayout(null);
		this.setSize(800,800);            //运行窗口大小
		this.setLocationRelativeTo(null);
		this.setVisible(true);

		// 个人信息查询
		JB1.setText("学生信息查询");
		JB1.setFont(new Font("黑体", Font.PLAIN, 20));//字体设置
		JB1.setBounds(120,420,200,40);//按钮位置及大小设置
		JB1.addActionListener(this);
		this.add(JB1);

		// 个人成绩查询
		JB2.setText("学生信息删除");
		JB2.setFont(new Font("黑体", Font.PLAIN, 20));
		JB2.setBounds(350,420,200,40);
		JB2.addActionListener(this);
		this.add(JB2);

		// 修改密码
		JB3.setText("学生信息添加");
		JB3.setFont(new Font("黑体", Font.PLAIN, 20));
		JB3.setBounds(120,540,200,40);
		JB3.addActionListener(this);
		this.add(JB3);


		JB4.setText("学生信息修改");
		JB4.setFont(new Font("黑体", Font.PLAIN, 20));
		JB4.setBounds(350,540,200,40);
		JB4.addActionListener(this);
		this.add(JB4);

		// 设置图片大小
		this.setLayout(null);
		this.add(label);
		label.setBounds(0,0,700,400);

		addWindowListener(new WindowAdapter() {
			public void windowClosing (WindowEvent e)
			{
				dispose();
			}
		});

	}

//通过按按钮使信息转自相应页面
	@Override
	public void actionPerformed(ActionEvent e) {
		// 查询信息
		if(e.getSource()==JB1)
		{
			new Get_users();
		}
		// 删除信息
		else if(e.getSource()==JB2)
		{
			new Delete_users();
		}
		// 增添信息
		else if(e.getSource()==JB3)
		{
			new Add_users();

		}
		//更改信息
		else if (e.getSource()==JB4)
		{
			new Update_users();
		}
	}
	public static void main(String[] args) {
		String name  = "111";
		new employee(name);
	}
}

在这里插入图片描述
在这里插入图片描述
修改后界面：
在这里插入图片描述

原网站

版权声明
本文为[terrific51]所创，转载请带上原文链接，感谢
https://blog.csdn.net/weixin_68746494/article/details/125744888

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