如何在sparkjava中按顺序管理事务？

<dependencies>
    <dependency>
        <groupId>com.sparkjava</groupId>
        <artifactId>spark-core</artifactId>
        <version>2.9.3</version>
    </dependency>
    <dependency>
        <!-- 添加你使用的数据库驱动依赖 -->
    </dependency>
</dependencies>

import static spark.Spark.*;

public class Main {
    public static void main(String[] args) {
        // 创建数据库连接
        // ...

        // 开启事务
        before((request, response) -> {
            try {
                connection.setAutoCommit(false);
            } catch (SQLException e) {
                e.printStackTrace();
                halt(500, "Failed to start transaction");
            }
        });

        // 定义路由和处理逻辑
        // ...

        // 提交事务
        after((request, response) -> {
            try {
                connection.commit();
            } catch (SQLException e) {
                e.printStackTrace();
                halt(500, "Failed to commit transaction");
            }
        });

        // 回滚事务
        exception(Exception.class, (exception, request, response) -> {
            try {
                connection.rollback();
            } catch (SQLException e) {
                e.printStackTrace();
                halt(500, "Failed to rollback transaction");
            }
        });
    }
}

post("/users", (request, response) -> {
    // 获取请求参数
    String username = request.queryParams("username");
    String password = request.queryParams("password");

    // 执行数据库插入操作
    try {
        PreparedStatement statement = connection.prepareStatement("INSERT INTO users (username, password) VALUES (?, ?)");
        statement.setString(1, username);
        statement.setString(2, password);
        statement.executeUpdate();
    } catch (SQLException e) {
        e.printStackTrace();
        halt(500, "Failed to insert user");
    }

    return "User created successfully";
});

after((request, response) -> {
    // 关闭数据库连接
    try {
        connection.close();
    } catch (SQLException e) {
        e.printStackTrace();
        halt(500, "Failed to close connection");
    }
});