服务器可能在很短时间内承受大量的客户端请求，客户端请求的数量可能超过服务器本身即时处理能力，而服务端程序又不能丢弃任何一个客户请求。此时最佳处理方案莫过于让客户端请求进行排队，由服务端程序一个接一个处理，这样既保证了所有客户端请求均不丢失，同时也避免了服务器由于同时处理太多请求而崩溃。
public class Request {
private String name;
public Request(String name) {
this.name = name;
}
public String getName() {
return name;
}
public String toString() {
return "[ Request " + name + " ]";
}
}
import java.util.LinkedList;
public class RequestQueue {
private LinkedList queue = new LinkedList();
public synchronized Request getRequest() {
while (queue.size() == 0) {
try {
wait();
} catch (InterruptedException e) {
}
}
return (Request)queue.remove();
}
public synchronized void addRequest(Request request) {
queue.add(request);
notifyAll();
}
}
public class ServerThread extends Thread {
private RequestQueue requestQueue;
public ServerThread(RequestQueue requestQueue, String name) {
super(name);
this.requestQueue = requestQueue;
}
public void run() {
while (true) {
final Request request = requestQueue.getRequest();
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName() + " handles " + request);
}
}
}
public class ClientThread extends Thread {
private RequestQueue requestQueue;
public ClientThread(RequestQueue requestQueue, String name) {
super(name);
this.requestQueue = requestQueue;
}
public void run() {
for (int i = 0; i < 10; i++) {
Request request = new Request("RequestID:" + i+" Thread_Name:"+Thread.currentThread().getName());
System.out.println(Thread.currentThread().getName() + " requests " + request);
requestQueue.addRequest(request);
try {
Thread.sleep(10);
} catch (InterruptedException e) {
}
System.out.println("ClientThread Name is:"+Thread.currentThread().getName());
}
System.out.println(Thread.currentThread().getName()+" request end");
}
}
public class Main {
public static void main(String[] args) {
RequestQueue requestQueue = new RequestQueue();
for(int i=0;i<5;i++) //创建5个服务端线程
new ServerThread(requestQueue, "ServerThread"+i).start();
for(int i=0;i<5;i++) //创建5个客户端线程
new ClientThread(requestQueue, "ClientThread"+i).start();
}
}
输出结果
ClientThread0 requests [ Request RequestID:0 Thread_Name:ClientThread0 ] ClientThread1 requests [ Request RequestID:0 Thread_Name:ClientThread1 ] ClientThread2 requests [ Request RequestID:0 Thread_Name:ClientThread2 ] ClientThread3 requests [ Request RequestID:0 Thread_Name:ClientThread3 ] ClientThread4 requests [ Request RequestID:0 Thread_Name:ClientThread4 ] ClientThread Name is:ClientThread0 ClientThread Name is:ClientThread1 ClientThread0 requests [ Request RequestID:1 Thread_Name:ClientThread0 ] ClientThread1 requests [ Request RequestID:1 Thread_Name:ClientThread1 ] ClientThread Name is:ClientThread2 ClientThread Name is:ClientThread3 ClientThread Name is:ClientThread4 ClientThread4 requests [ Request RequestID:1 Thread_Name:ClientThread4 ] ClientThread3 requests [ Request RequestID:1 Thread_Name:ClientThread3 ] ClientThread2 requests [ Request RequestID:1 Thread_Name:ClientThread2 ] ClientThread Name is:ClientThread1 ClientThread Name is:ClientThread0 ClientThread0 requests [ Request RequestID:2 Thread_Name:ClientThread0 ] ClientThread1 requests [ Request RequestID:2 Thread_Name:ClientThread1 ] ClientThread Name is:ClientThread2 ClientThread Name is:ClientThread3 ClientThread Name is:ClientThread4 ClientThread2 requests [ Request RequestID:2 Thread_Name:ClientThread2 ] ClientThread4 requests [ Request RequestID:2 Thread_Name:ClientThread4 ] ClientThread3 requests [ Request RequestID:2 Thread_Name:ClientThread3 ] ClientThread Name is:ClientThread1 ClientThread Name is:ClientThread0 ClientThread1 requests [ Request RequestID:3 Thread_Name:ClientThread1 ] ClientThread0 requests [ Request RequestID:3 Thread_Name:ClientThread0 ] ClientThread Name is:ClientThread2 ClientThread Name is:ClientThread3 ClientThread Name is:ClientThread4 ClientThread3 requests [ Request RequestID:3 Thread_Name:ClientThread3 ] ClientThread2 requests [ Request RequestID:3 Thread_Name:ClientThread2 ] ClientThread4 requests [ Request RequestID:3 Thread_Name:ClientThread4 ] ClientThread Name is:ClientThread0 ClientThread0 requests [ Request RequestID:4 Thread_Name:ClientThread0 ] ClientThread Name is:ClientThread4 ClientThread4 requests [ Request RequestID:4 Thread_Name:ClientThread4 ] ClientThread Name is:ClientThread2 ClientThread Name is:ClientThread1 ClientThread1 requests [ Request RequestID:4 Thread_Name:ClientThread1 ] ClientThread2 requests [ Request RequestID:4 Thread_Name:ClientThread2 ] ClientThread Name is:ClientThread3 ClientThread3 requests [ Request RequestID:4 Thread_Name:ClientThread3 ] ClientThread Name is:ClientThread3 ClientThread3 requests [ Request RequestID:5 Thread_Name:ClientThread3 ] ClientThread Name is:ClientThread2 ClientThread Name is:ClientThread0 ClientThread Name is:ClientThread4 ClientThread Name is:ClientThread1 ClientThread4 requests [ Request RequestID:5 Thread_Name:ClientThread4 ] ClientThread1 requests [ Request RequestID:5 Thread_Name:ClientThread1 ] ClientThread0 requests [ Request RequestID:5 Thread_Name:ClientThread0 ] ClientThread2 requests [ Request RequestID:5 Thread_Name:ClientThread2 ] ClientThread Name is:ClientThread2 ClientThread Name is:ClientThread3 ClientThread Name is:ClientThread4 ClientThread Name is:ClientThread1 ClientThread Name is:ClientThread0 ClientThread1 requests [ Request RequestID:6 Thread_Name:ClientThread1 ] ClientThread4 requests [ Request RequestID:6 Thread_Name:ClientThread4 ] ClientThread3 requests [ Request RequestID:6 Thread_Name:ClientThread3 ] ClientThread2 requests [ Request RequestID:6 Thread_Name:ClientThread2 ] ClientThread0 requests [ Request RequestID:6 Thread_Name:ClientThread0 ] ClientThread Name is:ClientThread0 ClientThread Name is:ClientThread1 ClientThread Name is:ClientThread4 ClientThread Name is:ClientThread2 ClientThread Name is:ClientThread3 ClientThread2 requests [ Request RequestID:7 Thread_Name:ClientThread2 ] ClientThread4 requests [ Request RequestID:7 Thread_Name:ClientThread4 ] ClientThread1 requests [ Request RequestID:7 Thread_Name:ClientThread1 ] ClientThread0 requests [ Request RequestID:7 Thread_Name:ClientThread0 ] ClientThread3 requests [ Request RequestID:7 Thread_Name:ClientThread3 ] ClientThread Name is:ClientThread3 ClientThread3 requests [ Request RequestID:8 Thread_Name:ClientThread3 ] ClientThread Name is:ClientThread0 ClientThread0 requests [ Request RequestID:8 Thread_Name:ClientThread0 ] ClientThread Name is:ClientThread1 ClientThread1 requests [ Request RequestID:8 Thread_Name:ClientThread1 ] ClientThread Name is:ClientThread4 ClientThread4 requests [ Request RequestID:8 Thread_Name:ClientThread4 ] ClientThread Name is:ClientThread2 ClientThread2 requests [ Request RequestID:8 Thread_Name:ClientThread2 ] ServerThread4 handles [ Request RequestID:0 Thread_Name:ClientThread0 ] ServerThread0 handles [ Request RequestID:0 Thread_Name:ClientThread1 ] ClientThread Name is:ClientThread4 ClientThread Name is:ClientThread3 ClientThread Name is:ClientThread0 ServerThread1 handles [ Request RequestID:0 Thread_Name:ClientThread3 ] ClientThread Name is:ClientThread1 ServerThread3 handles [ Request RequestID:0 Thread_Name:ClientThread2 ] ClientThread0 requests [ Request RequestID:9 Thread_Name:ClientThread0 ] ClientThread3 requests [ Request RequestID:9 Thread_Name:ClientThread3 ] ServerThread2 handles [ Request RequestID:0 Thread_Name:ClientThread4 ] ClientThread4 requests [ Request RequestID:9 Thread_Name:ClientThread4 ] ClientThread1 requests [ Request RequestID:9 Thread_Name:ClientThread1 ] ClientThread Name is:ClientThread2 ClientThread2 requests [ Request RequestID:9 Thread_Name:ClientThread2 ] ClientThread Name is:ClientThread2 ClientThread2 request end ClientThread Name is:ClientThread4 ClientThread4 request end ClientThread Name is:ClientThread3 ClientThread3 request end ClientThread Name is:ClientThread0 ClientThread0 request end ClientThread Name is:ClientThread1 ClientThread1 request end ServerThread0 handles [ Request RequestID:1 Thread_Name:ClientThread1 ] ServerThread4 handles [ Request RequestID:1 Thread_Name:ClientThread0 ] ServerThread2 handles [ Request RequestID:1 Thread_Name:ClientThread2 ] ServerThread1 handles [ Request RequestID:1 Thread_Name:ClientThread4 ] ServerThread3 handles [ Request RequestID:1 Thread_Name:ClientThread3 ] ServerThread4 handles [ Request RequestID:2 Thread_Name:ClientThread1 ] ServerThread0 handles [ Request RequestID:2 Thread_Name:ClientThread0 ] ServerThread2 handles [ Request RequestID:2 Thread_Name:ClientThread2 ] ServerThread3 handles [ Request RequestID:2 Thread_Name:ClientThread3 ] ServerThread1 handles [ Request RequestID:2 Thread_Name:ClientThread4 ] ServerThread4 handles [ Request RequestID:3 Thread_Name:ClientThread1 ] ServerThread0 handles [ Request RequestID:3 Thread_Name:ClientThread0 ] ServerThread3 handles [ Request RequestID:3 Thread_Name:ClientThread2 ] ServerThread2 handles [ Request RequestID:3 Thread_Name:ClientThread3 ] ServerThread1 handles [ Request RequestID:3 Thread_Name:ClientThread4 ] ServerThread0 handles [ Request RequestID:4 Thread_Name:ClientThread4 ] ServerThread4 handles [ Request RequestID:4 Thread_Name:ClientThread0 ] ServerThread1 handles [ Request RequestID:4 Thread_Name:ClientThread3 ] ServerThread3 handles [ Request RequestID:4 Thread_Name:ClientThread2 ] ServerThread2 handles [ Request RequestID:4 Thread_Name:ClientThread1 ] ServerThread4 handles [ Request RequestID:5 Thread_Name:ClientThread4 ] ServerThread0 handles [ Request RequestID:5 Thread_Name:ClientThread3 ] ServerThread2 handles [ Request RequestID:5 Thread_Name:ClientThread2 ] ServerThread1 handles [ Request RequestID:5 Thread_Name:ClientThread1 ] ServerThread3 handles [ Request RequestID:5 Thread_Name:ClientThread0 ] ServerThread3 handles [ Request RequestID:6 Thread_Name:ClientThread0 ] ServerThread1 handles [ Request RequestID:6 Thread_Name:ClientThread2 ] ServerThread2 handles [ Request RequestID:6 Thread_Name:ClientThread3 ] ServerThread0 handles [ Request RequestID:6 Thread_Name:ClientThread4 ] ServerThread4 handles [ Request RequestID:6 Thread_Name:ClientThread1 ] ServerThread3 handles [ Request RequestID:7 Thread_Name:ClientThread2 ] ServerThread1 handles [ Request RequestID:7 Thread_Name:ClientThread4 ] ServerThread2 handles [ Request RequestID:7 Thread_Name:ClientThread1 ] ServerThread0 handles [ Request RequestID:7 Thread_Name:ClientThread0 ] ServerThread4 handles [ Request RequestID:7 Thread_Name:ClientThread3 ] ServerThread4 handles [ Request RequestID:8 Thread_Name:ClientThread2 ] ServerThread0 handles [ Request RequestID:8 Thread_Name:ClientThread4 ] ServerThread2 handles [ Request RequestID:8 Thread_Name:ClientThread1 ] ServerThread1 handles [ Request RequestID:8 Thread_Name:ClientThread0 ] ServerThread3 handles [ Request RequestID:8 Thread_Name:ClientThread3 ] ServerThread3 handles [ Request RequestID:9 Thread_Name:ClientThread2 ] ServerThread1 handles [ Request RequestID:9 Thread_Name:ClientThread1 ] ServerThread2 handles [ Request RequestID:9 Thread_Name:ClientThread4 ] ServerThread0 handles [ Request RequestID:9 Thread_Name:ClientThread3 ] ServerThread4 handles [ Request RequestID:9 Thread_Name:ClientThread0 ]
参考：Java程序性能优化