测试线程安全代码针对锁ID实现

待我称王封你为后i 2021-09-25 08:54 153阅读 0赞

测试线程安全代码

package com.game.exe;
    
    import java.util.concurrent.ConcurrentHashMap;
    import java.util.concurrent.ExecutorService;
    import java.util.concurrent.Executors;
    import java.util.concurrent.locks.ReentrantLock;
    /**
     * 测试线程安全方法
     * @author gaoyannan
     * 20210513
     */
    public class Test {
    
    	public static void main(String[] args) {
    		// TODO Auto-generated method stub
    		String userId_a = "userId_a";
    		String userId_b = "userId_b";
    		String userId_c = "userId_c";
    		String userId_d = "userId_d";
    		String userId_e = "userId_e";
    		String userId_f = "userId_f";
    		int count = 10000 * 100;
    		long startTime = System.currentTimeMillis();
    
    		thread1(userId_a, count);
    		thread2(userId_b, count);
    		thread3(userId_c, count);
    		thread4(userId_d, count);
    		thread5(userId_e, count);
    		thread6(userId_f, count);
    		EXECUTOR_SERVICE.shutdown();
    		while (true) {// 等待所有任务都执行结束
    			if (EXECUTOR_SERVICE.isTerminated()) {// 所有的子线程都结束了
    				System.err.println("共耗时:" + (System.currentTimeMillis() - startTime) / 1000.0 + "s");
    				break;
    			}
    		}
    		System.err.println(userId_a + " 线程不安全 没有锁 i1==" + i1);
    		System.err.println(userId_b + "  线程安全 synchronized (CHM.get(userId)) 锁userId i2==" + i2);
    		System.err.println(userId_c + "  线程安全 synchronized (userId.intern()) 锁userId i3==" + i3);
    		System.err.println(userId_d + "  线程安全 synchronized void count4 锁所有 i4==" + i4);
    		System.err.println(userId_e + "  线程安全 synchronized (Test.class) 锁所有 i5==" + i5);
    		System.err.println(userId_f + "  线程安全 lock.lock(); 锁所有 i6==" + i6);
    		
    	}
    	/**
    	 * 公平锁
    	 */
    	private static final ReentrantLock lock = new ReentrantLock(true);
    	private static final ExecutorService EXECUTOR_SERVICE = Executors.newCachedThreadPool();
    	static {// 添加钩子 确保 关闭jar前线程池的任务运行完毕
    		Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
    
    			public void run() {
    				try {
    					EXECUTOR_SERVICE.shutdown();
    				} catch (Exception e) {
    					// TODO: handle exception
    					e.printStackTrace();
    				}
    
    			}
    		}));
    	}
    	public static int i1 = 0;
    	public static int i2 = 0;
    	public static int i3 = 0;
    	public static int i4 = 0;
    	public static int i5 = 0;
    	public static int i6 = 0;
    	public static final ConcurrentHashMap<String, String> CHM = new ConcurrentHashMap<String, String>();
    
    	/**
    	 * 线程不安全
    	 */
    	public static void thread1(String userId, int count) {
    		for (int i = 0; i < count; i++) {
    			EXECUTOR_SERVICE.execute(new Runnable() {
    
    				@Override
    				public void run() {
    					// TODO Auto-generated method stub
    					count1(userId);
    				}
    			});
    		}
    
    	}
    
    	/**
    	 * 线程安全
    	 */
    	public static void thread2(String userId, int count) {
    		CHM.put(userId, userId);
    		for (int i = 0; i < count; i++) {
    
    			EXECUTOR_SERVICE.execute(new Runnable() {
    
    				@Override
    				public void run() {
    					// TODO Auto-generated method stub
    					count2(userId);
    
    				}
    			});
    		}
    
    	}
    
    	/**
    	 * 线程安全
    	 */
    	public static void thread3(String userId, int count) {
    		for (int i = 0; i < count; i++) {
    			EXECUTOR_SERVICE.execute(new Runnable() {
    
    				@Override
    				public void run() {
    					// TODO Auto-generated method stub
    
    					count3(userId);
    
    				}
    			});
    		}
    
    	}
    
    	/**
    	 * 线程安全
    	 */
    	public static void thread4(String userId, int count) {
    		for (int i = 0; i < count; i++) {
    			EXECUTOR_SERVICE.execute(new Runnable() {
    
    				@Override
    				public void run() {
    					// TODO Auto-generated method stub
    
    					count4(userId);
    
    				}
    			});
    		}
    
    	}
    
    	/**
    	 * 线程安全
    	 */
    	public static void thread5(String userId, int count) {
    		for (int i = 0; i < count; i++) {
    			EXECUTOR_SERVICE.execute(new Runnable() {
    
    				@Override
    				public void run() {
    					// TODO Auto-generated method stub
    
    					count5(userId);
    
    				}
    			});
    		}
    
    	}
    	/**
    	 * 线程安全
    	 */
    	public static void thread6(String userId, int count) {
    		for (int i = 0; i < count; i++) {
    			EXECUTOR_SERVICE.execute(new Runnable() {
    
    				@Override
    				public void run() {
    					// TODO Auto-generated method stub
    
    					count6(userId);
    
    				}
    			});
    		}
    
    	}
    
    	/**
    	 * 线程不安全 锁不住
    	 */
    	public static void count1(String userId) {
    
    		i1++;
    	}
    
    	/**
    	 * 线程安全 锁userId
    	 */
    	public static void count2(String userId) {
    		synchronized (CHM.get(userId)) {
    			i2++;
    		}
    
    	}
    
    	/**
    	 * 线程安全 锁userId
    	 */
    	public static void count3(String userId) {
    		synchronized (userId.intern()) {
    			i3++;
    		}
    	}
    
    	/**
    	 * 线程安全 锁所有
    	 */
    	public static synchronized void count4(String userId) {
    		i4++;
    
    	}
    
    	/**
    	 * 线程安全 锁所有
    	 */
    	public static synchronized void count5(String userId) {
    		synchronized (Test.class) {// 锁所有
    			i5++;
    		}
    	}
    	/**
    	 * 线程安全 锁所有
    	 * @param userId
    	 */
    	public static void count6(String userId) {
    		try {
    			lock.lock();
    			i6++;
    			//lock.unlock();
    		} catch (Exception e) {
    			// TODO: handle exception
    			e.printStackTrace();
    		} finally {
    			// TODO: handle finally clause
    			if (lock.isLocked()) {
    				lock.unlock();
    			}
    		}
    	}
    
    }