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ivan19861025
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Java并发编程-生成唯一序列号

    博客分类:
  • Java
 
阅读更多

所用到的并发编程库

import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.ReentrantReadWriteLock;

 

package com.league.idgenerate;

/**
 * 
 * ID生成器接口, 用于生成全局唯一的ID流水号
 * 
 * @author Ivan.Ma
 */
public interface IdGenerator {
	
	/**
	 * 生成下一个不重复的流水号
	 * @return
	 */
	String next();
	
}

 

package com.league.idgenerate;

/**
 * ID生成器的配置接口
 * @author Ivan.Ma
 */
public interface IdGeneratorConfig {
	
	/**
	 * 获取分隔符
	 * @return
	 */
	String getSplitString();
	
	/**
	 * 获取初始值
	 * @return
	 */
	int getInitial(); 
	
	/**
	 * 获取ID前缀
	 * @return
	 */
	String getPrefix();
	
	/**
	 * 获取滚动间隔, 单位: 秒
	 * @return
	 */
	int getRollingInterval();
	
}

 

package com.league.idgenerate;

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.ReentrantReadWriteLock;


/**
 * 默认的ID生成器, 采用前缀+时间+原子数的形式实现
 * 建议相同的配置采用同一个实例
 * @see IdGeneratorConfig
 * @author Ivan.Ma
 */
public class DefaultIdGenerator implements IdGenerator, Runnable{
	
	private String time;
	
	private AtomicInteger value;
	
	private static final DateTimeFormatter FORMATTER = DateTimeFormatter.ofPattern("yyyyMMddHHmmss");
	
	private IdGeneratorConfig config;
	
	private Thread thread;
	
	private ReentrantReadWriteLock lock = new ReentrantReadWriteLock();
	
	public DefaultIdGenerator(){
		config = new DefaultIdGeneratorConfig();
		time = LocalDateTime.now().format(FORMATTER);
		value = new AtomicInteger(config.getInitial());
		
		thread = new Thread(this);
		thread.setDaemon(true);
		thread.start();
	}
	
	public DefaultIdGenerator(IdGeneratorConfig config){
		this.config = config;
		time = LocalDateTime.now().format(FORMATTER);
		value = new AtomicInteger(config.getInitial());
		
		thread = new Thread(this);
		thread.setDaemon(true);
		thread.start();
	}
	
	@Override
	public String next() {
		lock.readLock().lock();
		StringBuffer sb = new StringBuffer(config.getPrefix()).append(config.getSplitString()).append(time).append(config.getSplitString()).append(value.getAndIncrement());
		lock.readLock().unlock();
		return sb.toString();
	}
	
	@Override
	public void run() {
		while (true){
			try {
				Thread.sleep(1000 * config.getRollingInterval());
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			String now = LocalDateTime.now().format(FORMATTER);
			if (!now.equals(time)){
				lock.writeLock().lock();
				time = now;
				value.set(config.getInitial());
				lock.writeLock().unlock();
			}
		}
	}
	
}

 

package com.league.idgenerate;

public class DefaultIdGeneratorConfig implements IdGeneratorConfig{

	@Override
	public String getSplitString() {
		return "";
	}

	@Override
	public int getInitial() {
		return 1;
	}

	@Override
	public String getPrefix() {
		return "";
	}

	@Override
	public int getRollingInterval() {
		return 1;
	}

}

 测试类, 该类主要演示如何使用及相关测试功能代码,如下:

package com.league.idgenerate;

import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import org.junit.Test;

/**
 * 用法说明
 * @author Ivan.Ma
 */
public class TestStandaloneIdGenerator {
	
	@Test
	public void test1(){
		IdGenerator idGenerator = new DefaultIdGenerator();
		
		System.out.println("--------简单测试------------------");
		for (int i=0; i<100; i++){
			System.out.println(idGenerator.next());
		}
	}
	
	@Test
	public void test2(){
		IdGenerator idGenerator = new DefaultIdGenerator();
		
		//多线程测试
		System.out.println("--------多线程测试不重复------------------");
		Set<String> idSet = Collections.synchronizedSet(new HashSet<>());
		ExecutorService es = Executors.newFixedThreadPool(100);
		for (int i=0; i<2000000; i++){
			es.submit(() -> {
				String val = idGenerator.next();
				if (idSet.contains(val)){
					System.out.println("重复了: " + val);
				}else{
					idSet.add(val);
				}
			});
		}
		es.shutdown();
		System.out.println("启用顺序关闭");
		while(true){  
            if(es.isTerminated()){
                System.out.println("所有的子线程都结束了!");  
                break;
            }
            try {
            	System.out.println("子线程的任务还没运行完");
				Thread.sleep(1000);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
        }  
		System.out.println("共生成: " + idSet.size() + "个");
	}
	
	@Test
	public void  test3(){
		//测试单机性能
		System.out.println("--------测试单线程性能------------------");
		IdGenerator idGenerator2 = new DefaultIdGenerator();
		long t1 = System.currentTimeMillis();
		int total = 10000000;
		for (int i=0; i<total; i++){
			idGenerator2.next();
		}
		System.out.println("单线程生成" + total + "个ID共耗时: " + (System.currentTimeMillis() - t1) + "ms");
	}
	
	//500个线程并发, 每个线程获取10000个ID
	@Test
	public void test4(){
		//测试多线程性能
		System.out.println("--------测试多线程性能------------------");
		ExecutorService es1 = Executors.newFixedThreadPool(500);
		IdGenerator idGenerator3 = new DefaultIdGenerator();
		long t1 = System.currentTimeMillis();
		for (int i=0; i<500; i++){
			es1.submit(() -> {
				int count = 0;
				while (count < 10000){
					idGenerator3.next();
					
					count++;
				}
			});
		}
		es1.shutdown();
		System.out.println("启用顺序关闭");
		while(true){  
            if(es1.isTerminated()){
                System.out.println("所有的子线程都结束了!");  
                break;
            }
            try {
            	System.out.println("子线程的任务还没运行完");
				Thread.sleep(200);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
        }  
		System.out.println("500线程,每个线程生成10000个序列号.共耗时: " + (System.currentTimeMillis() - t1) + " ms");
	}
	
	@Test
	public void test5(){
		System.out.println("--------测试生成的ID是否有时间滚动----------");
		IdGenerator idGenerator = new DefaultIdGenerator();
		for (int i=0; i<20; i++){
			String id = idGenerator.next();
			System.out.println(id);
			try {
				Thread.sleep(100);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
	
	@Test
	public void test6(){
		System.out.println("--------ID生成器的特殊设置相关----------");
		IdGeneratorConfig config = new DefaultIdGeneratorConfig() {
			@Override
			public String getSplitString() {
				return "-";
			}
			@Override
			public int getInitial() {
				return 1000000;
			}
			@Override
			public String getPrefix() {
				return "NODE01";
			}
		};
		IdGenerator idGenerator = new DefaultIdGenerator(config);
		for (int i=0; i<20; i++){
			String id = idGenerator.next();
			System.out.println(id);
			try {
				Thread.sleep(1000 * 1);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
}

 运行结果如下:

--------简单测试------------------
201602031124321
201602031124322
201602031124323
201602031124324
201602031124325
201602031124326
201602031124327
201602031124328
201602031124329
2016020311243210
2016020311243211
2016020311243212
2016020311243213
2016020311243214
2016020311243215
2016020311243216
2016020311243217
2016020311243218
2016020311243219
2016020311243220
2016020311243221
2016020311243222
2016020311243223
2016020311243224
2016020311243225
2016020311243226
2016020311243227
2016020311243228
2016020311243229
2016020311243230
2016020311243231
2016020311243232
2016020311243233
2016020311243234
2016020311243235
2016020311243236
2016020311243237
2016020311243238
2016020311243239
2016020311243240
2016020311243241
2016020311243242
2016020311243243
2016020311243244
2016020311243245
2016020311243246
2016020311243247
2016020311243248
2016020311243249
2016020311243250
2016020311243251
2016020311243252
2016020311243253
2016020311243254
2016020311243255
2016020311243256
2016020311243257
2016020311243258
2016020311243259
2016020311243260
2016020311243261
2016020311243262
2016020311243263
2016020311243264
2016020311243265
2016020311243266
2016020311243267
2016020311243268
2016020311243269
2016020311243270
2016020311243271
2016020311243272
2016020311243273
2016020311243274
2016020311243275
2016020311243276
2016020311243277
2016020311243278
2016020311243279
2016020311243280
2016020311243281
2016020311243282
2016020311243283
2016020311243284
2016020311243285
2016020311243286
2016020311243287
2016020311243288
2016020311243289
2016020311243290
2016020311243291
2016020311243292
2016020311243293
2016020311243294
2016020311243295
2016020311243296
2016020311243297
2016020311243298
2016020311243299
20160203112432100
--------多线程测试不重复------------------
启用顺序关闭
子线程的任务还没运行完
子线程的任务还没运行完
子线程的任务还没运行完
子线程的任务还没运行完
子线程的任务还没运行完
所有的子线程都结束了!
共生成: 2000000个
--------测试单线程性能------------------
单线程生成10000000个ID共耗时: 1972ms
--------测试多线程性能------------------
启用顺序关闭
子线程的任务还没运行完
子线程的任务还没运行完
子线程的任务还没运行完
子线程的任务还没运行完
子线程的任务还没运行完
子线程的任务还没运行完
子线程的任务还没运行完
所有的子线程都结束了!
500线程,每个线程生成10000个序列号.共耗时: 1605 ms
--------测试生成的ID是否有时间滚动----------
201602031124431
201602031124432
201602031124433
201602031124434
201602031124435
201602031124436
201602031124437
201602031124438
201602031124439
2016020311244310
2016020311244311
201602031124441
201602031124442
201602031124443
201602031124444
201602031124445
201602031124446
201602031124447
201602031124448
201602031124449
--------ID生成器的特殊设置相关----------
NODE01-20160203112445-1000000
NODE01-20160203112445-1000001
NODE01-20160203112446-1000000
NODE01-20160203112447-1000000
NODE01-20160203112448-1000000
NODE01-20160203112449-1000000
NODE01-20160203112450-1000000
NODE01-20160203112452-1000000
NODE01-20160203112453-1000000
NODE01-20160203112454-1000000
NODE01-20160203112455-1000000
NODE01-20160203112456-1000000
NODE01-20160203112457-1000000
NODE01-20160203112458-1000000
NODE01-20160203112459-1000000
NODE01-20160203112500-1000000
NODE01-20160203112501-1000000
NODE01-20160203112502-1000000
NODE01-20160203112503-1000000
NODE01-20160203112504-1000000

 从该性能来看, 可以使用在高并发的场景, 欢迎大家来拍砖!

 

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5 楼 ivan19861025 2016-02-24  
ivan19861025 写道
Saro 写道
提醒一下,SimpleDateFormat不是线程安全的。

* Date formats are not synchronized.
* It is recommended to create separate format instances for each thread.
* If multiple threads access a format concurrently, it must be synchronized
* externally.


我并没有改变simpledateformat内部状态, 有什么问题呢?

看了源代码,simpledateformat内部使用了calendar, 确实有线程安全的问题.更改为java8的time相关api实现
4 楼 ivan19861025 2016-02-16  
Saro 写道
提醒一下,SimpleDateFormat不是线程安全的。

* Date formats are not synchronized.
* It is recommended to create separate format instances for each thread.
* If multiple threads access a format concurrently, it must be synchronized
* externally.


我并没有改变simpledateformat内部状态, 有什么问题呢?
3 楼 ivan19861025 2016-02-16  
dieslrae 写道
你就没考虑过集群环境?

集群有什么问题呢? 集群用前面的节点来区分.保证全局唯一
2 楼 dieslrae 2016-02-03  
你就没考虑过集群环境?
1 楼 Saro 2016-02-03  
提醒一下,SimpleDateFormat不是线程安全的。

* Date formats are not synchronized.
* It is recommended to create separate format instances for each thread.
* If multiple threads access a format concurrently, it must be synchronized
* externally.

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