Java connects MySQL to implement data addition, deletion, modification, and attachment of actual code

Environment introduction:

Editor: Eclipse

mysql database jar package: mysql-connector-java-8.0.22.jar

java version: 1.8*

How to load eclipse jar package, refer to  https://jingyan.baidu.com/article/f3e34a127f837db5eb6535d3.html  here is not the main focus

main content:

The main method code is as follows:

	public static void main(String[] args) {
		
//		声明Connection对象
		Connection con = null;
		// 驱动程序名
//		String driver = "com.mysql.jdbc.Driver"; //  可能会提示错误信息 但是不影响
		String driver = "com.mysql.cj.jdbc.Driver"; // MySql 6版本使用
		
		// 数据库链接 ip:port    其中test为数据库
		String url = "jdbc:mysql://105.105.105.105:3306/test"; 
//      用户名   自行修改
		String user = "***"; 
//      密码  自行修改
		String password  = "********"; 
//      目标数据表 自行修改
		String table = "*****";
		
		System.out.println("数据查询");
		query_sql(con,driver,url,user,password,table);
		
		System.out.println("数据插入");
		add_sql(con,driver,url,user,password,table);
		
		System.out.println("数据删除");
		del_sql(con,driver,url,user,password,table);
		
		System.out.println("数据更改");
		update_sql(con,driver,url,user,password,table);
	}

One: Increase of data (insert)

	// 增
	public static void add_sql(Connection con,String driver,String url,String user,String password,String table){
		
		String min_ip = "210.69.0.1	";
		String max_ip = "210.69.255.224";
		try {
			Class.forName(driver);
			// 链接MySql
			con = DriverManager.getConnection(url,user,password);			
			if(!con.isClosed()) {
				System.out.println("数据库连接成功");
			};
			String insert_sql = "insert into " + table + " (minip,maxip) values(?,?)";
			PreparedStatement ps = con.prepareStatement(insert_sql);
//          注意形参？的下标从1开始
			ps.setString(1, min_ip);
			ps.setString(2, max_ip);
			int num = ps.executeUpdate();
			if(num == 1) {
				System.out.println("数据插入成功");
			}else {
				System.out.println("数据插入失败");
			}
			ps.close();
			con.close();
		}catch(SQLException e) {
			e.printStackTrace();
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
	}

Two: the deletion of data (delete)

// 删
	public static void del_sql(Connection con,String driver, String url,String user,String password,String table) {
		try {
			Class.forName(driver);
			con = DriverManager.getConnection(url,user,password);
			if (!con.isClosed()) {
				System.out.println("数据库连接成功！！！");
			}
			String del_sqlString = "delete from " + table + " where id = ? ;";
			PreparedStatement ps = con.prepareStatement(del_sqlString);
//          删除id为73837的数据记录
			ps.setInt(1, 73837);  
			int num = ps.executeUpdate();
			System.out.println(num);
			if (num == 1) {
				System.out.println("数据删除成功");
			}else {
				System.out.println("数据删除失败");
			}
			ps.close();
			con.close();
		} catch (Exception e) {
			e.printStackTrace();
		} 
	}

Three: data changes (update)

// 改
	public static void update_sql(Connection con,String driver,String url,String user,String password,String table) {
		try {
			Class.forName(driver);
			con = DriverManager.getConnection(url,user,password);
			if (!con.isClosed()) {
				System.out.println("数据库连接成功");
			}
			String up_sql = "update " + table + " set minip = ? where id = ?;";
			PreparedStatement ps = con.prepareStatement(up_sql);
//          将id为73838的数据记录的minip更新为"8888888"
			ps.setString(1, "8888888");
			ps.setInt(2, 73838);
			int num = ps.executeUpdate();
			if (num == 1) {
				System.out.println("数据更新成功");
			}else {
				System.out.println("数据更新失败");
			}
			ps.close();
			con.close();
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

Four: data query (query)

// 查
	public static void query_sql(Connection con, String driver, String url, String user, String password,String table) {
		try {
			// 加载驱动程序
			Class.forName(driver);
			// 连接MySql
			con = DriverManager.getConnection(url,user,password);
			if(!con.isClosed()) {
				System.out.println("数据库连接成功");
			};
			// 创建statement类对象 用来执行SQL语句
			Statement statement = con.createStatement();
			String sql = "select minip,maxip from " + table + " limit 10 ";
			ResultSet rs = statement.executeQuery(sql);
			while(rs.next()) {
				String minip = rs.getString("minip"); // 字段名minip
				String maxip = rs.getString("maxip"); // 字段名maxip
				System.out.println(minip + " ---- " + maxip);
			}
			System.out.println("关闭数据库连接");
			con.close(); //关闭数据库
		} catch(ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		}
	}

Summary : The above is a simple operation of adding, deleting, modifying and checking when java connects to mysql database

Remarks: The above-mentioned one main method and 4 non-main methods can be placed in the same class for calling. I have tested it. Available