多线程httpClient [英] Multi-Threading httpClient
本文介绍了多线程httpClient的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
public class test {
public static final int nThreads = 2;
public static void main(String[] args) throws ExecutionException, InterruptedException{
// Runnable myrunnable = new myRunnable();
ExecutorService execute = Executors.newFixedThreadPool(nThreads);
for (int i = 0; i < nThreads; ++i) {
execute.execute(new MyTask());
}
execute.awaitTermination(1000, TimeUnit.MILLISECONDS);
execute.shutdown();
}
}
class MyTask implements Runnable {
public static final int maxCalls = 10;
public static final int sleepMillis = 500;
private static HttpResponse response;
private static HttpClient httpclient;
public void run(){
int counter = 0;
while (true) {
if (counter >= maxCalls) {
break;
}
try {
Thread.currentThread().sleep(sleepMillis);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
execHttpRequest();
++counter;
}
}
private void execHttpRequest() {
httpclient = new DefaultHttpClient();
HttpGet httpget = new HttpGet("My URL");
try {
response = httpclient.execute(httpget);
BufferedReader br = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
String output;
while((output=br.readLine())!=null){
System.out.println(Thread.currentThread().getName() +output);
}
br.close();
httpclient.getConnectionManager().shutdown();
//httpclient.getConnectionManager().shutdown();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
finally{
httpclient.getConnectionManager().shutdown();
}
}
}
运行此代码时,我得到以下异常:
While running this code, I get the following exception:
Exception in thread "pool-1-thread-1" java.lang.IllegalStateException: Invalid use of SingleClientConnManager: connection still allocated.
Make sure to release the connection before allocating another one.
at org.apache.http.impl.conn.SingleClientConnManager.getConnection(SingleClientConnManager.java:216)
at org.apache.http.impl.conn.SingleClientConnManager$1.getConnection(SingleClientConnManager.java:190)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:401)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:820)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:754)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:732)
at MyTask.execHttpRequest(test.java:72)
at MyTask.run(test.java:60)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
java.io.InterruptedIOException: Connection has been shut down
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:543)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:820)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:754)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:732)
at MyTask.execHttpRequest(test.java:72)
at MyTask.run(test.java:60)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
Caused by: org.apache.http.impl.conn.ConnectionShutdownException
at org.apache.http.impl.conn.AbstractPooledConnAdapter.assertValid(AbstractPooledConnAdapter.java:86)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.getRoute(AbstractPooledConnAdapter.java:112)
at org.apache.http.impl.client.DefaultRequestDirector.establishRoute(DefaultRequestDirector.java:740)
at org.apache.http.impl.client.DefaultRequestDirector.tryConnect(DefaultRequestDirector.java:577)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:425)
... 8 more
当我执行http请求时,我会看到这些异常。它适用于单线程。我试图调用一个特定的URL(它工作得很好)但是当我向它添加多个线程时,它会抛出一个非法的状态异常。
When I execute http request, then I see these Exceptions. It works perfectly fine for single-threaded. I am trying to call a specific URL (which works perfectly fine) but when I add more than one thread to it, it throws an illegal state exception.
推荐答案
我意识到自己的愚蠢! httpClient和httpRequest都是静态的。在我使它们非静态之后它工作正常! Executor Service让我更好地控制线程管理,我热衷于使用它。
I realised my folly! httpClient and httpRequest were both static. After i made them non-static it works fine! Executor Service gives me better control on managing threads and I was keen on using it.
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