新建一个账户表

create table account (
    id int primary key auto_increment,
    `name` varchar(40),
    money float
);
insert into account(name, money) VALUES ('A',1000);
insert into account(name, money) VALUES ('B',1000);
insert into account(name, money) VALUES ('C',1000);

//数据库事务练习：转账

start transaction ;         #开启事务
update account set money = money - 100 where name ='A';
update account set money = money + 100 where name = 'B';
commit ;

//在代码中实现

@Test
public void test() {
    //useUnicode=true&characterEncoding=utf-8用来解决中文乱码
    String url = "jdbc:mysql://localhost:3306/jdbc?useUnicode=true&characterEncoding=utf-8";
    String username = "root";
    String password = "123456";
    Connection connection = null;
    try {
        //1.加载驱动
        Class.forName("com.mysql.jdbc.Driver");
        //2.连接数据库，代表数据库
        connection = DriverManager.getConnection(url, username, password);

    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    } catch (SQLException throwables) {
        throwables.printStackTrace();
    }

    try {
        //3.通知数据库开启事务
        connection.setAutoCommit(false);

        String sql = "update account set money = money - 100 where name ='A'";
        int i = connection.prepareStatement(sql).executeUpdate();

        String sql2 = "update account set money = money + 100 where name = 'B'";
        int i1 = connection.prepareStatement(sql2).executeUpdate();
        int y = 1/0;　　　　//手动出错，然事务回滚
        connection.commit();
        System.out.println("success");
    } catch (SQLException throwables) {
        try {
            connection.rollback();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }finally {
        try {
            connection.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }
}