代码之家 › 专栏 › 技术社区 › Arya

调用并将参数传递给另一个线程中的方法

multithreading java

Arya · 技术社区 · 7 年前

我创建了这个小项目来展示我想要做的事情,但实际上它将用于使用大约60个不同线程的大型应用程序中。

public class Main {

    public static void main(String[] args) {
        Http http = new Http();
        Thread threadHttp = new Thread(http, "httpThread1");
        threadHttp.start();

        http.getPage("http://google.com"); // <-- This gets called on 
                                           // the main thread, 
                                           //I want it to get called from the
                                            // "httpThread1" thread
    }
}

public class Http implements Runnable {
    volatile OkHttpClient client;

    @Override
    public void run() {
        client = new OkHttpClient.Builder().readTimeout(10, TimeUnit.SECONDS).retryOnConnectionFailure(true).build();

    }

    public void getPage(String url) {
        Request request = new Request.Builder().url(url).build();

        try {
            Response response = client.newCall(request).execute();
            System.out.println(response.body().string());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

从主线程,我希望能够调用 getPage 方法,但让它在 httpThread1 我们开始初始化了 OkHttpClient client

这可能吗?怎样才能做到呢?

3 回复 | 直到 7 年前

ernest_k Petronella 7 年前

Runnable#run 该方法是否设计用于执行 Runnable 对象所以你必须让它做你现在正在做的事情 getPage .

您可以使用状态来存储 url

class Http implements Runnable {

    //initialize Http. This can be done better perhaps
    volatile OkHttpClient client = new OkHttpClient.Builder()
            .readTimeout(10, TimeUnit.SECONDS)
            .retryOnConnectionFailure(true).build();

    private Response response;

    private String url;

    public Http(String url) {
        this.url = url;
    }

    @Override
    public void run() {
        this.getPage(this.url);
    }

    public void getPage(String url) {
        Request request = new Request.Builder().url(url).build();

        try {
            this.response = client.newCall(request).execute();
            System.out.println(response.body().string());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

在你的 main 方法:

Http http = new Http("http://google.com");
Thread threadHttp = new Thread(http, "httpThread1");
threadHttp.start();
threadHttp.join();
Response resp = http.getResponse();

然而,使用期货可以大大简化这一过程。例如,它可能看起来很简单:

class Http {
    volatile OkHttpClient client = new OkHttpClient.Builder()
            .readTimeout(10, TimeUnit.SECONDS)
            .retryOnConnectionFailure(true).build();

    public Response getPage(String url) {
        Request request = new Request.Builder().url(url).build();

        try {
            this.response = client.newCall(request).execute();
            System.out.println(response.body().string());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

而且,使用futures,您的主要方法看起来更简单:

public static void main(String[] args) throws Exception {
    Http http = new Http();
    CompletableFuture<Response> future = 
            CompletableFuture.supplyAsync(() -> http.getPage("http://google.com"));

    //the preceding statement will call `getPage` on a different thread.
    //So you can do other things before blocking with next statement

    Response resp = future.join();
}

您甚至可以将线程池用于 supplyAsync 如果您需要更多地控制异步任务的运行方式。

joshkmartinez 7 年前

你可以打电话给 test 方法在 Updater 像这样的课程: updater.test(yourVarHere)
this question
您可能还想查看 Java concurrency tutorial

Jonathan JOhx 7 年前

class HttpThread extends Thread {
     volatile OkHttpClient client;

     HttpThread(Runnable target, String name) {
        super(target, name);
     }

     @Override
     public void run() {
        client = new OkHttpClient.Builder().readTimeout(10, TimeUnit.SECONDS).retryOnConnectionFailure(true).build();
     }

     public void getPage(String url) {
        Request request = new Request.Builder().url(url).build();
        try {
            Response response = client.newCall(request).execute();
            System.out.println(response.body().string());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
 }

在主要课程中:

public class Main {

   public static void main(String[] args) {
       Thread httpThread = new HttpThread(http, "httpThread1");
       httpThread.start();
       httpThread.getPage("http://google.com"); 
    }
}