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JMeter讲解---至媳妇儿

1.如何录请求

先解释什么叫代理服务器,代理服务器是一个程序,运行在特定的IP地址和端口号上。

  1. 无代理服务器:HTTP请求直接发送出去。

  1. 有代理服务器:HTTP请求先通过代理服务器,代理服务器再转发出去。

JMeter和Charles会创建一个HTTP代理服务器(HTTP Proxy Server),拦截所有从操作系统上发出的HTTP请求并记录,这就是录请求的原理。

2.如何进行性能测试

JMeter通过线程组来模拟真实用户对Web服务器的访问压力,创建许多个线程来并发的给目的地址发送HTTP请求。

2.1 如何使用Java创建线程

public class TestThread {

    public static void main(String[] args) {
        for (int i = 0; i < 10; i++) {
            MyThread thread = new MyThread(i);
            thread.start();
        }
    }
}

class MyThread extends Thread {

    public int a;

    public MyThread(int a) {
        this.a = a;
    }

    @Override
    public void run() {
        System.out.println(a);
    }

}

运行结果:

0
3
4
2
1
6
5
7
8
9

2.2 如何使用Java发送一个HTTP请求

public class MockHTTP {
    public static void get(String url) {
        try {
            URL target = new URL(url);
            HttpURLConnection connection = (HttpURLConnection) target.openConnection();
            InputStream is = connection.getInputStream();
            int len = connection.getContentLength();
            byte[] b = new byte[len];
            is.read(b, 0, len);
            System.out.println(new String(b, StandardCharsets.UTF_8));
        } catch (java.io.IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        get("http://www.baidu.com");
    }
}

结果:

<!DOCTYPE html>
<!--STATUS OK--><html> <head><meta http-equiv=content-type content=text/html;charset=utf-8><meta http-equiv=X-UA-Compatible content=IE=Edge><meta content=always name=referrer><link rel=stylesheet type=text/css href=http://s1.bdstatic.com/r/www/cache/bdorz/baidu.min.css><title>百度一下,你就知道</title></head> <body link=#0000cc> <div id=wrapper> <div id=head> <div class=head_wrapper> <div class=s_form> <div class=s_form_wrapper> <div id=lg> <img hidefocus=true src=//www.baidu.com/img/bd_logo1.png width=270 height=129> </div> <form id=form name=f action=//www.baidu.com/s class=fm> <input type=hidden name=bdorz_come value=1> <input type=hidden name=ie value=utf-8> <input type=hidden name=f value=8> <input type=hidden name=rsv_bp value=1> <input type=hidden name=rsv_idx value=1> <input type=hidden name=tn value=baidu><span class="bg s_ipt_wr"><input id=kw name=wd class=s_ipt value maxlength=255 autocomplete=off autofocus></span><span class="bg s_btn_wr"><input type=submit id=su value=百度一下 class="bg s_btn"></span> </form> </div> </div> <div id=u1> <a href=http://news.baidu.com name=tj_trnews class=mnav>新闻</a> <a href=http://www.hao123.com name=tj_trhao123 class=mnav>hao123</a> <a href=http://map.baidu.com name=tj_trmap class=mnav>地图</a> <a href=http://v.baidu.com name=tj_trvideo class=mnav>视频</a> <a href=http://tieba.baidu.com name=tj_trtieba class=mnav>贴吧</a> <noscript> <a href=http://www.baidu.com/bdorz/login.gif?login&amp;tpl=mn&amp;u=http%3A%2F%2Fwww.baidu.com%2f%3fbdorz_come%3d1 name=tj_login class=lb>登录</a> </noscript> <script>document.write('<a href="http://www.baidu.com/bdorz/login.gif?login&tpl=mn&u='+ encodeURIComponent(window.location.href+ (window.location.search === "" ? "?" : "&")+ "bdorz_come=1")+ '" name="tj_login" class="lb">登录</a>');</script> <a href=//www.baidu.com/more/ name=tj_briicon class=bri style="display: block;">更多产品</a> </div> </div> </div> <div id=ftCon> <div id=ftConw> <p id=lh> <a href=http://home.baidu.com>关于百度</a> <a href=http://ir.baidu.com>About Baidu</a> </p> <p id=cp>&copy;2017&nbsp;Baidu&nbsp;<a href=http://www.baidu.com/duty/>使用百度前必读</a>&nbsp; <a href=http://jianyi.baidu.com/ class=cp-feedback>意见反馈</a>&nbsp;京ICP证030173号&nbsp; <img src=//www.baidu.com/img/gs.gif> </p> </div> </div> </div> </body> </html>

2.3 如何使用Java并发发送请求

public class MockHTTPThreads {

    public static void main(String[] args) {
        for (int i = 0; i < 100; i++) {
            MyThread thread = new MyThread();
            thread.start();
        }
    }
}

class MyThread extends Thread {

    public void get(String url) {
        try {
            URL target = new URL(url);
            HttpURLConnection connection = (HttpURLConnection) target.openConnection();
            InputStream is = connection.getInputStream();
            int len = connection.getContentLength();
            byte[] b = new byte[len];
            is.read(b, 0, len);
            System.out.println(new String(b, StandardCharsets.UTF_8));
        } catch (java.io.IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void run() {
        get("http://www.baidu.com");
    }
}

结果:

100条百度首页的html。