多线程与高并发是近些年互联网的一大进步之一，小伙伴们知道多线程与高并发要怎么一起实现吗?下面小编就给大家讲解讲解。
后端测试代码：
import java.text.NumberFormat;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import com.dima.web.utils.HttpClientUtil;
/**
* 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 = 4;
int clientNum = 20000;
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
{
String sendGet = HttpClientUtil.sendGet("http://localhost:8080/Dima3773Web/Simulate", "");
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;
}
}
class ThreadRecord
{
long startTime;
long endTime;
public ThreadRecord(long st, long et)
{
this.startTime = st;
this.endTime = et;
}
}服务端servlet处理
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* java模拟多线程高并发--模拟服务器servlet
*/
public class SimulateServserServlet extends HttpServlet
{
private static final long serialVersionUID = 1 L;
public SimulateServserServlet()
{
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
String content = "测试数据";
System.out.println(System.currentTimeMillis() + "\t" + request.getRequestURL());
outPrintContent(response, content);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
{
doGet(request, response);
}
/**
* 返回输出 @Title: outPrintContent @Description: TODO @param @param
* content @param @param response 设定参数 @return void 返回类型 @throws
*/
public static void outPrintContent(ServletResponse response, String content)
{
response.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = null;
try
{
out = response.getWriter();
out.print(content);
out.flush();
}
catch (IOException e)
{
System.out.println("outprint content error : " + e);
}
finally
{
if (null != out)
{
out.close();
}
}
}
}以上就是今天的全部内容，如果还有一些不懂的java编程常见问题，可以来我们网站寻找答案。
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