package com.lynch.lock;import java.util.Map.Entry;/**   *** @author Lynch */
public class SendThread extends Thread {@Overridepublic void run() {try {sleep(6000);while (ConcurrentHashMapTest.pushMessage.size() > 0) {for (Entry<Integer, String> hashMap : ConcurrentHashMapTest.pushMessage.entrySet()) {System.out.println("消息id:" + hashMap.getKey()+ "未发送成功，在此重发:" + hashMap.getValue());}sleep(1000);}} catch (InterruptedException e) {e.printStackTrace();}}
}

package com.lynch.lock;import java.util.Map.Entry;/*** 接收发送过来的信息，并从内存中删除* * @author Administrator**/
public class ReceiveThread extends Thread {@Overridepublic void run() {try {for (int i = 0; i < 100000; i++) {sleep(2000);for (Entry<Integer, String> map : ConcurrentHashMapTest.pushMessage.entrySet()) {if (map.getKey() == i) {System.out.println("成功收到id为：" + map.getKey() + "返回的信息，删除该元素");ConcurrentHashMapTest.pushMessage.remove(map.getKey());}}System.out.println("内存对象中的元素数量为：" + ConcurrentHashMapTest.pushMessage.size());}} catch (InterruptedException e) {e.printStackTrace();}}
}

package com.lynch.lock;import java.util.concurrent.ConcurrentHashMap;/*** 模拟信息的发送和接收** @author Lynch*/
public class ConcurrentHashMapTest {public static ConcurrentHashMap<Integer, String> pushMessage = new ConcurrentHashMap<Integer, String>();public static void main(String[] args) {for (int i = 0; i < 5; i++) {pushMessage.put(i, "该消息是id为" + i + "的消息");}Thread sendThread = new SendThread();Thread receiveThread = new ReceiveThread();sendThread.start();receiveThread.start();for (int i = 5; i < 10; i++) {pushMessage.put(i, "该消息是id为" + i + "的消息");}}
}