需求:
我需要一个java代码,每3秒从数据库的aws_questions表里捞取enbale为0的最新5条数据,放到java程序的一个任务队列里。同时定义一个5个大小的线程池去处理任务队列里的数据,线程处理完就会去任务队列里捞取新的任务。要注意不要并发处理。
chatgpt4:
这是一个基本的Java代码示例,使用ScheduledExecutorService定期从数据库中获取数据,并使用FixedThreadPool来处理任务队列中的数据。请注意,您需要根据您的数据库连接和表结构进行相应的调整。
import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.Statement; import java.util.concurrent.*; public class DatabaseFetcher { private static final int THREAD_POOL_SIZE = 5; private static final int FETCH_INTERVAL_SECONDS = 3; private static BlockingQueue<Task> taskQueue = new LinkedBlockingQueue<>(); public static void main(String[] args) { ExecutorService taskExecutor = Executors.newFixedThreadPool(THREAD_POOL_SIZE); // 启动处理任务的线程 for (int i = 0; i < THREAD_POOL_SIZE; i++) { taskExecutor.execute(new TaskProcessor()); } // 定期从数据库获取数据 ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1); scheduler.scheduleAtFixedRate(() -> { try { fetchTasksFromDatabase(); } catch (Exception e) { System.err.println("Error fetching tasks from database: " + e.getMessage()); } }, 0, FETCH_INTERVAL_SECONDS, TimeUnit.SECONDS); } private static void fetchTasksFromDatabase() throws Exception { String url = "jdbc:mysql://your-database-url"; String user = "your-username"; String password = "your-password"; try (Connection connection = DriverManager.getConnection(url, user, password)) { Statement statement = connection.createStatement(); ResultSet resultSet = statement.executeQuery("SELECT * FROM aws_questions WHERE enbale = 0 ORDER BY id DESC LIMIT 5"); while (resultSet.next()) { Task task = new Task(resultSet.getInt("id"), resultSet.getString("question")); taskQueue.offer(task); } } } static class TaskProcessor implements Runnable { @Override public void run() { while (true) { try { Task task = taskQueue.take(); processTask(task); } catch (InterruptedException e) { System.err.println("Error processing task: " + e.getMessage()); } } } private void processTask(Task task) { // 处理任务逻辑 System.out.println("Processing task: " + task); } } static class Task { private int id; private String question; public Task(int id, String question) { this.id = id; this.question = question; } public int getId() { return id; } public String getQuestion() { return question; } @Override public String toString() { return "Task{" + "id=" + id + ", question='" + question + '\'' + '}'; } } }
这个示例使用Java的ExecutorService
和ScheduledExecutorService
进行定期获取和处理任务。请根据您的实际需求进行相应的调整。