java模拟调用get请求

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import java.text.NumberFormat;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;



/**
 * java模拟多线程高并发
 * @author Administrator
 *
 */
public class MultiThreadProxyHubApiTest {
    static int count = 0;
    // 总访问量是clientNum，并发量是threadNum
    int threadNum = 2;
    int clientNum = 2;

    float avgExecTime = 0;
    float sumexecTime = 0;
    long firstExecTime = Long.MAX_VALUE;
    long lastDoneTime = Long.MIN_VALUE;
    float totalExecTime = 0;

    public static void main(String[] args) {
        new MultiThreadProxyHubApiTest().run();
        System.out.println("finished!");
    }

    public void run() {

        final ConcurrentHashMap<Integer, ThreadRecord> records = new ConcurrentHashMap<Integer, ThreadRecord>();

        // 建立ExecutorService线程池，threadNum个线程可以同时访问
        ExecutorService exec = Executors.newFixedThreadPool(threadNum);
        // 模拟clientNum个客户端访问
        final CountDownLatch doneSignal = new CountDownLatch(clientNum);

        for (int i = 0; i < clientNum; i++) {
            Runnable run = new Runnable() {
                public void run() {
                    int index = getIndex();
                    long systemCurrentTimeMillis = System.currentTimeMillis();
                    try {
                        sendGet("http://localhost:9937/tcmp-management/disclosureProcess/syn");
                        System.out.println(System.currentTimeMillis()/* + sendGet*/);

                    } catch (Exception e) {
                        e.printStackTrace();
                    }

                    records.put(index, new ThreadRecord(systemCurrentTimeMillis, System.currentTimeMillis()));
                    doneSignal.countDown();// 每调用一次countDown()方法，计数器减1
                }
            };
            exec.execute(run);
        }

        try {
            // 计数器大于0 时，await()方法会阻塞程序继续执行
            doneSignal.await();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        /**
         * 获取每个线程的开始时间和结束时间
         */
        for (int i : records.keySet()) {
            ThreadRecord r = records.get(i);
            sumexecTime += ((double) (r.endTime - r.startTime)) / 1000;

            if (r.startTime < firstExecTime) {
                firstExecTime = r.startTime;
            }
            if (r.endTime > lastDoneTime) {
                this.lastDoneTime = r.endTime;
            }
        }

        this.avgExecTime = this.sumexecTime / records.size();
        this.totalExecTime = ((float) (this.lastDoneTime - this.firstExecTime)) / 1000;
        NumberFormat nf = NumberFormat.getNumberInstance();
        nf.setMaximumFractionDigits(4);

        System.out.println("======================================================");
        System.out.println("线程数量:\t\t" + threadNum);
        System.out.println("客户端数量:\t" + clientNum);
        System.out.println("平均执行时间:\t" + nf.format(this.avgExecTime) + "秒");
        System.out.println("总执行时间:\t" + nf.format(this.totalExecTime) + "秒");
        System.out.println("吞吐量:\t\t" + nf.format(this.clientNum / this.totalExecTime) + "次每秒");
    }

    public static int getIndex() {
        return ++count;
    }

    /**
     * 向指定URL发送GET方法的请求
     *
     * @param url
     *   发送请求的URL
     * @param param
     *   请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
     * @return URL 所代表远程资源的响应结果
     */
    public static String sendGet(String url) {
        String result = "";
        BufferedReader in = null;
        try {
            String urlNameString = url;
            URL realUrl = new URL(urlNameString);
            // 打开和URL之间的连接
            URLConnection connection = realUrl.openConnection();
            // 设置通用的请求属性
            connection.setRequestProperty("accept", "*/*");
            connection.setRequestProperty("connection", "Keep-Alive");
            connection.setRequestProperty("user-agent",
                    "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            // 建立实际的连接
            connection.connect();
            // 获取所有响应头字段
            Map<String, List<String>> map = connection.getHeaderFields();
            // 遍历所有的响应头字段
            for (String key : map.keySet()) {
                System.out.println(key + "--->" + map.get(key));
            }
            // 定义 BufferedReader输入流来读取URL的响应
            in = new BufferedReader(new InputStreamReader(
                    connection.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            System.out.println("发送GET请求出现异常！" + e);
            e.printStackTrace();
        }
        // 使用finally块来关闭输入流
        finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
        return result;
    }

}

class ThreadRecord {
    long startTime;
    long endTime;

    public ThreadRecord(long st, long et) {
        this.startTime = st;
        this.endTime = et;
    }

}