java mysql不重复读写

import java.sql.*;

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

        try (Connection conn = DriverManager.getConnection(url, user, password)) {
            conn.setAutoCommit(false); // 关闭自动提交
            conn.setTransactionIsolation(Connection.TRANSACTION_REPEATABLE_READ); // 设置隔离级别为可重复读

            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery("SELECT balance FROM accounts WHERE id = 1");

            if (rs.next()) {
                double balance = rs.getDouble("balance");
                System.out.println("Initial balance: " + balance);

                // 模拟另一个事务修改数据
                Thread.sleep(1000);
                rs = stmt.executeQuery("SELECT balance FROM accounts WHERE id = 1");
                if (rs.next()) {
                    double newBalance = rs.getDouble("balance");
                    System.out.println("New balance: " + newBalance);
                }
            }

            conn.commit(); // 提交事务
        } catch (SQLException | InterruptedException e) {
            e.printStackTrace();
        }
    }
}