一、使用的技術

HashMap

ConcurrentHashMap

Lock

ReadWriteLock

synchronized

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二、一百萬并發下的組合

ConcurrentLockMap

/** To change this license header, choose License Headers in Project Properties.* To change this template file, choose Tools | Templates* and open the template in the editor.*/ package cn.edu.scau.mk.map;import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock;/**** @author MK*/ public class ConcurrentLockMap implements In {ConcurrentHashMap<Integer, Integer> map = new ConcurrentHashMap<>();Lock lock = new ReentrantLock();@Overridepublic void add(int a) {lock.lock();try {if (map.containsKey(a)) {map.put(a, 1 + map.get(a));} else {map.put(a, 1);}} finally {lock.unlock();}}@Overridepublic int get(int a) {int as = map.get(a);return as;}} View Code

ConcurrentSynchronizedMap

package cn.edu.scau.mk.map;import java.util.concurrent.ConcurrentHashMap;/**** @author MK*/ public class ConcurrentSynchronizedMap implements In {ConcurrentHashMap<Integer, Integer> map = new ConcurrentHashMap<>();@Overridepublic void add(int a) {synchronized ((""+a).intern()) {if (map.containsKey(a)) {map.put(a, 1 + map.get(a));} else {map.put(a, 1);}}}@Overridepublic int get(int a) {int as = map.get(a);return as;}} View Code

LockHashMap

package cn.edu.scau.mk.map;import java.util.HashMap; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock;/**** @author MK*/ public class LockHashMap implements In {HashMap<Integer, Integer> map = new HashMap<>();Lock lock = new ReentrantLock();@Overridepublic void add(int a) {lock.lock();try {if (map.containsKey(a)) {map.put(a, 1 + map.get(a));} else {map.put(a, 1);}} finally {lock.unlock();}}@Overridepublic int get(int a) {int as = 0;lock.lock();try {map.get(a);} finally {lock.unlock();}return as;}} View Code

ReadWriteHashMap

/** To change this license header, choose License Headers in Project Properties.* To change this template file, choose Tools | Templates* and open the template in the editor.*/ package cn.edu.scau.mk.map;import java.util.HashMap; import java.util.concurrent.locks.ReentrantReadWriteLock;/**** @author MK*/ public class ReadWriteHashMap implements In {HashMap<Integer, Integer> map = new HashMap<>();ReentrantReadWriteLock lock = new ReentrantReadWriteLock();//390 @Overridepublic void add(int a) {lock.writeLock().lock();try {if (map.containsKey(a)) {map.put(a, 1 + map.get(a));} else {map.put(a, 1);}} finally {lock.writeLock().unlock();}}@Overridepublic int get(int a) {int as = 0;lock.readLock().lock();try {as = map.get(a);} finally {lock.readLock().unlock();}return as;}} View Code

SynchronizedHashMap

/** To change this license header, choose License Headers in Project Properties.* To change this template file, choose Tools | Templates* and open the template in the editor.*/ package cn.edu.scau.mk.map;import java.util.HashMap;/**** @author MK*/ public class SynchronizedHashMap implements In {HashMap<Integer, Integer> map = new HashMap<>();@Overridepublic synchronized void add(int a) {if (map.containsKey(a)) {map.put(a, 1 + map.get(a));} else {map.put(a, 1);}}@Overridepublic synchronized int get(int a) {int as = map.get(a);return as;}} View Code

In

package cn.edu.scau.mk.map;/**** @author MK*/ public interface In {void add(int a);int get(int a);} View Code

Adder

/** To change this license header, choose License Headers in Project Properties.* To change this template file, choose Tools | Templates* and open the template in the editor.*/ package cn.edu.scau.mk.map;import java.util.Random;/**** @author MK*/ public class Adder implements Runnable {In in;Random random = new Random();public Adder(In in) {this.in=in;}@Overridepublic void run() {for (int i = 0; i < 1000; i++) {//in.add(random.nextInt()); in.add(i);}} } View Code

Getter

/** To change this license header, choose License Headers in Project Properties.* To change this template file, choose Tools | Templates* and open the template in the editor.*/ package cn.edu.scau.mk.map;import java.util.Random;/**** @author MK*/ public class Getter implements Runnable {In in;Random random = new Random();public Getter(In in) {this.in=in;}@Overridepublic void run() {for (int i = 0; i < 1000; i++) {//in.add(random.nextInt()); in.get(i);}} } View Code

TestDemo

package cn.edu.scau.mk.map;import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import java.util.concurrent.ThreadPoolExecutor; import java.util.concurrent.TimeUnit;/**** @author MK*/ public class TestDemo {public static void main(String[] args) {In in = null;in = new ReadWriteHashMap();operate(in);in = new ConcurrentSynchronizedMap();operate(in);in = new ConcurrentLockMap();operate(in);in = new SynchronizedHashMap();operate(in);in = new LockHashMap();operate(in);}public static void operate(In in) {int poolSize = 1000000;Adder add = new Adder(in);ThreadPoolExecutor threadPool = (ThreadPoolExecutor) Executors.newCachedThreadPool();long start = System.currentTimeMillis();for (int i = 0; i < poolSize; i++) {threadPool.execute(add);}System.out.println(threadPool.getActiveCount());threadPool.shutdown();try {//等待直到所有任務完成 threadPool.awaitTermination(Long.MAX_VALUE, TimeUnit.MINUTES);long end = System.currentTimeMillis() - start;System.out.print(in.getClass().getSimpleName()+" add:" + end);} catch (InterruptedException e) {e.printStackTrace();}Getter get = new Getter(in);threadPool = (ThreadPoolExecutor) Executors.newCachedThreadPool();start = System.currentTimeMillis();for (int i = 0; i < poolSize; i++) {threadPool.execute(add);}threadPool.shutdown();try {//等待直到所有任務完成 threadPool.awaitTermination(Long.MAX_VALUE, TimeUnit.MINUTES);long end = System.currentTimeMillis() - start;System.out.println(" get:" + end);} catch (InterruptedException e) {e.printStackTrace();}} } View Code

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三、輸出結果

（1）一萬并發

6642
ReadWriteHashMap add:1263 get:983
7
ConcurrentSynchronizedMap add:577 get:546
7373
ConcurrentLockMap add:1515 get:1731
7783
SynchronizedHashMap add:1810 get:1607
6632
LockHashMap add:1092 get:1029

（2）十萬并發

58095
ReadWriteHashMap add:149181 get:69606
1443
ConcurrentSynchronizedMap add:5678 get:6631
54623
ConcurrentLockMap add:84595 get:77182
48390
SynchronizedHashMap add:63958 get:64696
49078
LockHashMap add:64606 get:64364

（3）百萬并發

681252
ReadWriteHashMap add:215943 get:85792
25145
ConcurrentSynchronizedMap add:80593 get:76485
546230
ConcurrentLockMap add:912461 get:821907
636318
SynchronizedHashMap add:845893 get:850142
500129
LockHashMap add:792271 get:808326

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