使用HttpURLConnection时遇到的资源未释放的问题
http://blog.sina.com.cn/s/blog_56beadc60100j9zu.html
今天自己写了一个压力测试的小程序,同时启100个线程,每个线程都串行地访问应用服务器上的一个jsp页面200次。在程序运行了一会儿以后,问题来了:
- java.net.SocketException: No buffer space available (maximum connections reached?): connect
- at java.net.PlainSocketImpl.socketConnect(Native Method)
- at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
- at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
- at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
- at java.net.Socket.connect(Socket.java:516)
- at java.net.Socket.connect(Socket.java:466)
- at sun.net.NetworkClient.doConnect(NetworkClient.java:157)
- at sun.net.www.http.HttpClient.openServer(HttpClient.java:365)
- at sun.net.www.http.HttpClient.openServer(HttpClient.java:477)
- at sun.net.www.http.HttpClient.<init>(HttpClient.java:214)
- at sun.net.www.http.HttpClient.New(HttpClient.java:287)
- at sun.net.www.http.HttpClient.New(HttpClient.java:299)
- at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:796)
- at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:748)
- at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:673)
- at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:840)
到网上查了查,应该是资源耗尽了,但是没有找到解决的方法。
程序片断代码如下:
- for (int j = 0; j < 200; j++) {
- long beginTime = System.currentTimeMillis();
- URL url = new URL("...");
- HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
- httpURLConnection.setDoOutput(true);
- httpURLConnection.setRequestMethod("POST");
- OutputStream os = httpURLConnection.getOutputStream();
- keywordNum = random.nextInt(myKeywords.length);
- os.write(("keyword=" + myKeywords[keywordNum]).getBytes("UTF8"));
- os.flush();
- os.close();
- int i = 0;
- int contentLength = 0;
- contentLength = httpURLConnection.getContentLength();
- long endTime = System.currentTimeMillis();
- System.out.println("Thread '" + name + "' search keyword '" + myKeywords[keywordNum] + "' and get content in " + (endTime - beginTime) + " Millis, length=" + contentLength);
- }
后来想了想,既然资源没释放,释放就可以了。查了一下HttpURLConnection有个disconnect方法,但是加上后也没有用。再找,jdk的docs里说,HttpURLConnection这个对象关掉相关的InputStream和OutputStream可以释放掉相关资源,于是试了下,在contentLength = httpURLConnection.getContentLength();这行后面又加了2行:
- InputStream is = httpURLConnection.getInputStream();
- is.close();
问题解决了。
原来只是知道如果不调用httpURLConnection的getContentLength或其它get方法,请求是不会提交的,一般如果不需要也不会去调getInputStream,没想到还有个释放资源的问题。
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简单的概括下释放httpUrlConnection的资源就是:
调用HttpURLConnection的disConnecn方法,还要关掉关联的inputStream和outputStream
posted on 2018-01-07 14:34 nickTimer 阅读(5819) 评论(1) 编辑 收藏 举报