摘要：項(xiàng)目地址，另外知乎同名文章也是我發(fā)布的，大家可以多多關(guān)注首先觀察控制臺其次再看本地壁紙庫現(xiàn)在進(jìn)入正題，這個(gè)小項(xiàng)目用到了具體版本見，另外還用到了中的線程池阻塞隊(duì)列生產(chǎn)消費(fèi)者模式文件監(jiān)聽服務(wù)，所以至少要求版本為或者以上項(xiàng)目分為個(gè)類和一個(gè)方法入

項(xiàng)目地址，另外知乎同名文章也是我發(fā)布的，大家可以多多關(guān)注

首先觀察控制臺

其次再看本地壁紙庫

現(xiàn)在進(jìn)入正題，這個(gè)小項(xiàng)目用到了 Jsoup具體版本見 POM），另外還用到了 JDK中的線程池、阻塞隊(duì)列（生產(chǎn)-消費(fèi)者模式）、NIO2（文件監(jiān)聽服務(wù) API），所以至少要求 JDK版本為7或者以上

項(xiàng)目分為5個(gè)類和一個(gè)方法入口類

生產(chǎn)者類（任務(wù)：從列表頁拿到詳情頁鏈接并放入阻塞隊(duì)列）

public class Producer implements Runnable {

    private String name;
    private BlockingQueue blockingQueue;

    public Producer(String name, BlockingQueue blockingQueue) {
        this.name = name;
        this.blockingQueue = blockingQueue;
    }

    @Override
    public void run() {
        Document doc = null;
        try {
            for(int i = 1; i < 12018; i ++) {
                System.out.println();
                System.out.println();
                System.out.println("current page:" + i);
                System.out.println("-----------------------------------");
                if(i == 1) {
                    doc = Jsoup.connect("https://alpha.wallhaven.cc/latest").get();
                } else {
                    doc = Jsoup.connect("https://alpha.wallhaven.cc/latest?page=" + i).get();
                }
                Element div = doc.getElementById("thumbs");
                Elements sections = div.getElementsByTag("section");
                for (Element ele : sections) {
                    Elements links = ele.getElementsByClass("preview");
                    for (Element e : links) {
                        String href = e.attr("href");
                        blockingQueue.put(href);
                        System.out.println(name + " put " + href);
                    }
                }
            }
            blockingQueue.put("");
            System.out.println(name + " is over");
        } catch (IOException | InterruptedException e) {
            e.printStackTrace();
        } 
    }
}

消費(fèi)者類（任務(wù)：從隊(duì)列拿到鏈接并獲取圖片源地址并將下載任務(wù)交給一個(gè)緩存線程池）

public class Consumer implements Runnable {

    private String name;
    private BlockingQueue blockingQueue;
    private ExecutorService taskPool;

    public Consumer(String name, BlockingQueue blockingQueue, ExecutorService taskPool) {
        this.name = name;
        this.blockingQueue = blockingQueue;
        this.taskPool = taskPool;
    }

    @Override
    public void run() {
        Document doc = null;
        try {
            String href = null;
            while((href = blockingQueue.take()) != "") {
                System.out.println(name + " take " + href);
                doc = Jsoup.connect(href).get();
                Element img = doc.getElementById("wallpaper");
                String src = "https:" + img.attr("src");
                taskPool.submit(new DownloadTask(src));
            }
            System.out.println(name + " is over");
        } catch (IOException | InterruptedException e) {
            e.printStackTrace();
        } 
    }

}

下載任務(wù)執(zhí)行類（任務(wù)：下載圖片到本地）

public class DownloadTask implements Runnable {

    private static String path = "C:UsersaiyapengDesktopPaper";
    private String src;
    private String name;

    public DownloadTask(String src) {
        this.src = src;
        int n = src.lastIndexOf("/");
        this.name = src.substring(++n);
    }

    @Override
    public void run() {
        Response res = null;
        try {
            res = Jsoup.connect(src).ignoreContentType(true).timeout(30000).execute();
            byte[] bytes = res.bodyAsBytes();
            File file = new File(path + name);
            if (!file.exists()) {
                RandomAccessFile raf = new RandomAccessFile(file, "rw");
                raf.write(bytes);
                raf.close();
            }
        } catch (IOException e1) {
            e1.printStackTrace();
        }
    }

}

監(jiān)聽服務(wù)類（任務(wù)：將文件路徑注冊到監(jiān)聽服務(wù)上并開始監(jiān)聽）

public class ResourceListener {

    private static ExecutorService fixedThreadPool = Executors.newCachedThreadPool();

    private WatchService ws;

    private ResourceListener(String path) {
        try {
            ws = FileSystems.getDefault().newWatchService();
            start();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void start() {
        fixedThreadPool.execute(new Listener(ws));
    }

    public static void addListener(String path) {
        try {
            ResourceListener resourceListener = new ResourceListener(path);
            Path p = Paths.get(path);
            p.register(resourceListener.ws, StandardWatchEventKinds.ENTRY_CREATE);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

監(jiān)聽回調(diào)類（任務(wù)：執(zhí)行回調(diào)任務(wù)）

public class Listener implements Runnable {

    private WatchService service;

    public Listener(WatchService service) {
        this.service = service;
    }

    @Override
    public void run() {
        try {
            while (true) {
                WatchKey watchKey = service.take();
                List> watchEvents = watchKey.pollEvents();
                for (WatchEvent event : watchEvents) {
                    System.err.println(event.context() + "已下載");
                }
                watchKey.reset();
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        } 
    }
}

方法入口類

public class DownloadTaskExecutor {

    public static void main(String[] args) throws IOException {
        
        ResourceListener.addListener("C:UsersaiyapengDesktopPaper");
    
        BlockingQueue blockingQueue = new SynchronousQueue(true);
        ExecutorService proservice = Executors.newSingleThreadExecutor();
        ExecutorService conservice = Executors.newSingleThreadExecutor();
        ExecutorService taskPool = Executors.newCachedThreadPool();
        proservice.submit(new Producer("Producer", blockingQueue));
        conservice.submit(new Consumer("Consumer", blockingQueue, taskPool));
        proservice.shutdown();
        conservice.shutdown();
    }

}

最后就是設(shè)置壁紙庫并設(shè)定更換頻率

感謝大家，有問題可以再評論區(qū)留言~~