HashMap和ConcurrentHashMap的并发性能测试_枝叶飞扬

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HashMap和ConcurrentHashMap的并发性能测试

(2011-04-15 21:55:08)

标签：

hashmap

concurrent

并发性能测试

it

分类： JAVA

先看看代码吧，模拟1000个并发，每个测试1000次操作，循环测试10轮。分别测试Put和Get操作

import java.util.Collections;
import java.util.HashMap;
import java.util.Hashtable;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
public class T {
static final int threads = 1000;
static final int NUMBER = 1000;
public static void main(String[] args) throws Exception {
Map<String, Integer> hashmapSync = Collections
.synchronizedMap(new HashMap<String, Integer>());//同步的hashmap
Map<String, Integer> concurrentHashMap = new ConcurrentHashMap<String, Integer>();
Map<String, Integer> hashtable = new Hashtable<String, Integer>();
long totalA = 0;
long totalB = 0;
long totalC = 0;
for (int i = 0; i <= 10; i++) {
totalA += testPut(hashmapSync);
totalB += testPut(concurrentHashMap);
totalC += testPut(hashtable);
}
System.out.println("Put time HashMapSync=" + totalA + "ms.");
System.out.println("Put time ConcurrentHashMap=" + totalB + "ms.");
System.out.println("Put time Hashtable=" + totalC + "ms.");
totalA = 0;
totalB = 0;
totalC = 0;
for (int i = 0; i <= 10; i++) {
totalA += testGet(hashmapSync);
totalB += testGet(concurrentHashMap);
totalC += testGet(hashtable);
}
System.out.println("Get time HashMapSync=" + totalA + "ms.");
System.out.println("Get time ConcurrentHashMap=" + totalB + "ms.");
System.out.println("Get time Hashtable=" + totalC + "ms.");
}
public static long testPut(Map<String, Integer> map) throws Exception {
long start = System.currentTimeMillis();
for (int i = 0; i < threads; i++) {
new MapPutThread(map).start();
}
while (MapPutThread.counter > 0) {
Thread.sleep(1);
}
return System.currentTimeMillis() - start;
}
public static long testGet(Map<String, Integer> map) throws Exception {
long start = System.currentTimeMillis();
for (int i = 0; i < threads; i++) {
new MapPutThread(map).start();
}
while (MapPutThread.counter > 0) {
Thread.sleep(1);
}
return System.currentTimeMillis() - start;
}
}
class MapPutThread extends Thread {
static int counter = 0;
static Object lock = new Object();
private Map<String, Integer> map;
private String key = this.getId() + "";
MapPutThread(Map<String, Integer> map) {
synchronized (lock) {
counter++;
}
this.map = map;
}
public void run() {
for (int i = 1; i <= T.NUMBER; i++) {
map.put(key, i);
}
synchronized (lock) {
counter--;
}
}
}
class MapGetThread extends Thread {
static int counter = 0;
static Object lock = new Object();
private Map<String, Integer> map;
private String key = this.getId() + "";
MapGetThread(Map<String, Integer> map) {
synchronized (lock) {
counter++;
}
this.map = map;
}
public void run() {
for (int i = 1; i <= T.NUMBER; i++) {
map.get(key);
}
synchronized (lock) {
counter--;
}
}
}

运行结果：
Put time HashMapSync=3966ms.
Put time ConcurrentHashMap=1892ms.
Put time Hashtable=3892ms.
Get time HashMapSync=3812ms.
Get time ConcurrentHashMap=1828ms.
Get time Hashtable=3985ms.

结论：
ConcurrentHashMap的性能比同步的HashMap快一倍左右
同步的HashMap和Hashtable的性能相当

转自：http://blog.csdn.net/java2000_net/archive/2008/11/25/3373181.aspx

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