Java操作MySQL数据库模板

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本模板非常适用于正在学习计算机专业的大学生，在做课程设计时，难免会遇到需要使用到数据库的情况。这里强烈推荐使用MySQL数据库，为什么呢？简单说，社会上大部分的大中小型网络公司都在使用MySQL，成本低是一个很大的原因！

本模板主要是对MySQL数据库进行增删改查操作

主要版本号：

• mysql-connector-java-8.0.19

• mysql-8.0.20-winx64

添加数据

package com;
?
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
?
public class Insert {
    public static void main(String[] args) throws Exception {
        Class.forName("com.mysql.cj.jdbc.Driver");     //抛出异常，写法是固定的
        String url = "jdbc:mysql://localhost:3306/class?useUnicode=true&characterEncoding=utf8&useSSL=true&serverTimezone=UTC";
        String username = "root";     //数据库账户名
        String password = "123456";       //数据库登录密码
        Connection connection = DriverManager.getConnection(url, username, password);
        Statement statement = connection.createStatement();     //statement来执行sql的对象
        String sql = "INSERT INTO `student`(`name`,`pwd`,`sex`,`birthday`,`address`,`email`,`gradeid`)\n" +
                "VALUES(‘yfl‘,‘9933‘,‘女‘,‘1999-02-13‘,‘xiapu‘,‘102065@qq‘,‘2‘)";
        int num = statement.executeUpdate(sql);      //执行完sql后返回受影响的行数
        if(num>0)
            System.out.println("插入成功！");
        statement.close();
        connection.close();
    }
}
?

删除数据

package com;
?
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
?
public class Delete {
    public static void main(String[] args) throws Exception {
        Class.forName("com.mysql.cj.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/class?useUnicode=true&characterEncoding=utf8&useSSL=true&serverTimezone=UTC";
        String username = "root";     //数据库账户名
        String password = "123456";       //数据库登录密码
        Connection connection = DriverManager.getConnection(url, username, password);
        Statement statement = connection.createStatement();     //statement来执行sql的对象
        String sql = "DELETE FROM `student` WHERE id=5";
        int num = statement.executeUpdate(sql);      //执行完sql后返回受影响的行数
        if(num>0)
            System.out.println("删除成功！");
        statement.close();
        connection.close();
    }
}

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更新数据

package com;
?
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
?
public class Update {
    public static void main(String[] args) throws Exception {
        Class.forName("com.mysql.cj.jdbc.Driver");     //抛出异常，写法是固定的
        String url = "jdbc:mysql://localhost:3306/class?useUnicode=true&characterEncoding=utf8&useSSL=true&serverTimezone=UTC";
        String username = "root";     //数据库账户名
        String password = "123456";       //数据库登录密码
        Connection connection = DriverManager.getConnection(url, username, password);//需要抛出异常，"connection"就可以代表数据库了
        Statement statement = connection.createStatement();     //statement来执行sql的对象
        String sql = "UPDATE `student` SET `name`=‘atm‘ WHERE `id`=3";
        int num = statement.executeUpdate(sql);      //执行完sql后返回受影响的行数
        if(num>0)
            System.out.println("更新成功！");
        statement.close();
        connection.close();
    }
}

查询数据

package com;
?
import java.sql.*;
?
public class Select {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        //第一步：加载驱动
        Class.forName("com.mysql.cj.jdbc.Driver");     //抛出异常，写法是固定的
        //第二步：验证用户信息和url
        String url = "jdbc:mysql://localhost:3306/class?useUnicode=true&characterEncoding=utf8&useSSL=true&serverTimezone=UTC";
        String username = "root";     //数据库账户名
        String password = "123456";       //数据库登录密码
        //第三步：连接成功后获得数据库对象
        Connection connection = DriverManager.getConnection(url, username, password);//需要抛出异常，"connection"就可以代表数据库了
        //第四步：获取执行sql的对象
        Statement statement = connection.createStatement();     //statement来执行sql的对象
        //第五步：使用sql的对象去执行sql语句
        String sql = "SELECT * FROM `student`";
        ResultSet resultSet = statement.executeQuery(sql);      //执行完sql后返回一个结果集resultSet，这个结果集已经封装了全部查询出来的结果
        /*
        statement.executeQuery();//查询操作，返回ResultSet
        statement.execute();//可以执行任何SQL
        statement.executeUpdate();//更新、插入、删除都用它，返回一个受影响的行数（int）
         */
        while (resultSet.next()){       //对结果进行打印
            System.out.println("id="+resultSet.getObject("id"));  
            System.out.println("name="+resultSet.getObject("name"));
        }
        //第六步：使用完毕，释放数据库的连接
        resultSet.close();
        statement.close();
        connection.close();
        //释放连接尽量遵循先创建后释放的原则
    }
}

事实上，这样的模板更适用于操作量小的工程项目，不利于代码的整洁化，接下来小编将会把这些代码进行封装，在使用时只需要调用封装的接口即可。

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Java操作MySQL数据库模板

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