mysql java事物回滚

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

public class TransactionExample {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/mydatabase";
        String user = "username";
        String password = "password";

        Connection conn = null;
        PreparedStatement pstmt1 = null;
        PreparedStatement pstmt2 = null;

        try {
            // 1. 获取数据库连接
            conn = DriverManager.getConnection(url, user, password);

            // 2. 关闭自动提交，开启事务
            conn.setAutoCommit(false);

            // 3. 执行第一个SQL语句
            String sql1 = "UPDATE accounts SET balance = balance - 100 WHERE id = 1";
            pstmt1 = conn.prepareStatement(sql1);
            pstmt1.executeUpdate();

            // 4. 执行第二个SQL语句
            String sql2 = "UPDATE accounts SET balance = balance + 100 WHERE id = 2";
            pstmt2 = conn.prepareStatement(sql2);
            pstmt2.executeUpdate();

            // 5. 提交事务
            conn.commit();
        } catch (SQLException e) {
            // 6. 发生异常时回滚事务
            if (conn != null) {
                try {
                    conn.rollback();
                } catch (SQLException ex) {
                    ex.printStackTrace();
                }
            }
            e.printStackTrace();
        } finally {
            // 7. 关闭资源
            try {
                if (pstmt1 != null) pstmt1.close();
                if (pstmt2 != null) pstmt2.close();
                if (conn != null) conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}

conn.setTransactionIsolation(Connection.TRANSACTION_REPEATABLE_READ);