有时需要测试一下某个成果的并发机能,又不要想借助于其他东西,索性就本身的开拓语言,来一个并发请求就最利便了。
Java 中模仿并发请求,自然是很利便的,只要多开几个线程,提倡请求就好了。可是,这种请求,一般会存在启动的先后顺序了,算不得真正的同时并发!怎么样才气做到真正的同时并发呢?是本文想说的点,Java 中提供了闭锁 CountDownLatch, 恰好就用来做这种事就最符合了。
只需要:
package com.test; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import java.util.concurrent.CountDownLatch; public class LatchTest { public static void main(String[] args) throws InterruptedException { Runnable taskTemp = new Runnable() { // 留意,此处长短线程安详的,留坑 private int iCounter; @Override public void run() { for(int i = 0; i < 10; i++) { // 提倡请求 // HttpClientOp.doGet("https://www.baidu.com/"); iCounter++; System.out.println(System.nanoTime() + " [" + Thread.currentThread().getName() + "] iCounter = " + iCounter); try { Thread.sleep(100); } catch (InterruptedException e) { e.printStackTrace(); } } } }; LatchTest latchTest = new LatchTest(); latchTest.startTaskAllInOnce(5, taskTemp); } public long startTaskAllInOnce(int threadNums, final Runnable task) throws InterruptedException { final CountDownLatch startGate = new CountDownLatch(1); final CountDownLatch endGate = new CountDownLatch(threadNums); for(int i = 0; i < threadNums; i++) { Thread t = new Thread() { public void run() { try { // 使线程在此期待,当开始门打开时,一起涌入门中 startGate.await(); try { task.run(); } finally { // 将竣事门减1,减到0时,就可以开启竣事门了 endGate.countDown(); } } catch (InterruptedException ie) { ie.printStackTrace(); } } }; t.start(); } long startTime = System.nanoTime(); System.out.println(startTime + " [" + Thread.currentThread() + "] All thread is ready, concurrent going..."); // 因开启门只需一个开关,所以立马就开启开始门 startGate.countDown(); // 等等竣事门开启 endGate.await(); long endTime = System.nanoTime(); System.out.println(endTime + " [" + Thread.currentThread() + "] All thread is completed."); return endTime - startTime; } }
其执行结果如下图所示:
HttpClientOp 东西类,可以利用 成熟的东西包,也可以本身写一个扼要的会见要领,参考如下:
class HttpClientOp { public static String doGet(String httpurl) { HttpURLConnection connection = null; InputStream is = null; BufferedReader br = null; String result = null;// 返回功效字符串 try { // 建设长途url毗连工具 URL url = new URL(httpurl); // 通过长途url毗连工具打开一个毗连,强转成httpURLConnection类 connection = (HttpURLConnection) url.openConnection(); // 配置毗连方法:get connection.setRequestMethod("GET"); // 配置毗连主机处事器的超时时间:15000毫秒 connection.setConnectTimeout(15000); // 配置读取长途返回的数据时间:60000毫秒 connection.setReadTimeout(60000); // 发送请求 connection.connect(); // 通过connection毗连,获取输入流 if (connection.getResponseCode() == 200) { is = connection.getInputStream(); // 封装输入流is,并指定字符集 br = new BufferedReader(new InputStreamReader(is, "UTF-8")); // 存放数据 StringBuffer sbf = new StringBuffer(); String temp = null; while ((temp = br.readLine()) != null) { sbf.append(temp); sbf.append("\r\n"); } result = sbf.toString(); } } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { // 封锁资源 if (null != br) { try { br.close(); } catch (IOException e) { e.printStackTrace(); } } if (null != is) { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } connection.disconnect();// 封锁长途毗连 } return result; } public static String doPost(String httpUrl, String param) { HttpURLConnection connection = null; InputStream is = null; OutputStream os = null; BufferedReader br = null; String result = null; try { URL url = new URL(httpUrl); // 通过长途url毗连工具打开毗连 connection = (HttpURLConnection) url.openConnection(); // 配置毗连请求方法 connection.setRequestMethod("POST"); // 配置毗连主机处事器超时时间:15000毫秒 connection.setConnectTimeout(15000); // 配置读取主机处事器返回数据超时时间:60000毫秒 connection.setReadTimeout(60000); // 默认值为:false,当向长途处事器传送数据/写数据时,需要配置为true connection.setDoOutput(true); // 默认值为:true,当前向长途处事读取数据时,昆山软件开发,配置为true,该参数无关紧要 connection.setDoInput(true); // 配置传入参数的名目:请求参数应该是 name1=value1&name2=value2 的形式。 connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); // 配置鉴权信息:Authorization: Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0 connection.setRequestProperty("Authorization", "Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0"); // 通过毗连工具获取一个输出流 os = connection.getOutputStream(); // 通过输出流工具将参数写出去/传输出去,它是通过字节数组写出的 os.write(param.getBytes()); // 通过毗连工具获取一个输入流,昆山软件开发,向长途读取 if (connection.getResponseCode() == 200) { is = connection.getInputStream(); // 对输入流工具举办包装:charset按照事情项目组的要求来配置 br = new BufferedReader(new InputStreamReader(is, "UTF-8")); StringBuffer sbf = new StringBuffer(); String temp = null; // 轮回遍历一行一行读取数据 while ((temp = br.readLine()) != null) { sbf.append(temp); sbf.append("\r\n"); } result = sbf.toString(); } } catch (MalformedURLException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { // 封锁资源 if (null != br) { try { br.close(); } catch (IOException e) { e.printStackTrace(); } } if (null != os) { try { os.close(); } catch (IOException e) { e.printStackTrace(); } } if (null != is) { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } // 断开与长途地点url的毗连 connection.disconnect(); } return result; } }
如上,就可以提倡真正的并发请求了。
并发请求操纵流程示意图如下: