标签：

同步synchronized

同步方法

显式指纹（同步代码块）

public class TestCode {
	
	public static void main(String[] args) {
		TestCode1 t1 = new TestCode1();
		TestCode2 t2 = new TestCode2();
		TestCode3 t3 = new TestCode3();
		Thread ta = new Thread(t1, "A");
		Thread tb = new Thread(t2, "B");
		Thread tc = new Thread(t3, "C");
		ta.start();
		tb.start();
		tc.start();
	}
	
	private static TestCode test = new TestCode();

	public static class TestCode1 implements Runnable {
		public synchronized void run() {
			for (int i = 0; i < 5; i++) {
				try {
					Thread.sleep(1000);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				System.out.println(Thread.currentThread().getName()+" synchronized loop "+i);
			}
		}
	}
	
	public static class TestCode2 implements Runnable {
		public void run() {
			synchronized (test) {  //这里如果使用this则表示新实例，就不与其他代码块搞在一起
				for (int i = 0; i < 5; i++) {
					try {
						Thread.sleep(1000);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
					System.out.println(Thread.currentThread().getName()+" synchronized loop "+i);
				}
			}
		}
	}

	public static class TestCode3 implements Runnable {
		public void run() {
			synchronized (test) {  //这里如果使用this则表示新实例，就不与其他代码块搞在一起
				for (int i = 0; i < 5; i++) {
					try {
						Thread.sleep(1000);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
					System.out.println(Thread.currentThread().getName()+" synchronized loop "+i);
				}
			}
		}
	}
	
}

B synchronized loop 0
A synchronized loop 0
A synchronized loop 1
B synchronized loop 1
B synchronized loop 2
A synchronized loop 2
B synchronized loop 3
A synchronized loop 3
A synchronized loop 4
B synchronized loop 4
C synchronized loop 0
C synchronized loop 1
C synchronized loop 2
C synchronized loop 3
C synchronized loop 4

隐式指纹

public class TestSynchronized {

	private int count = 0;

	public synchronized void plus() {
		System.out.println("begin plus count="+count);
		count++;
		try {
			Thread.sleep(2000);
			System.out.println("end plus count="+count);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public synchronized void minus() {
		System.out.println("begin minus count="+count);
		count--;
		System.out.println("end minus count="+count);
	}

	public void print() {
		try {
			Thread.sleep(1000);
			System.out.println("print count="+count);
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public static void main(String[] args) throws Exception {
		final TestSynchronized ts = new TestSynchronized();
		Thread thread_plus = new Thread("thread_plus") {
			public void run() {
				System.out.println("Thread:" + super.getName());
				ts.plus();
			}
		};

		final Thread thread_minus = new Thread("thread_minus") {
			public void run() {
				System.out.println("Thread:" + super.getName());
				//改变ts.sub和ts.print的执行顺序，看看是什么情况
				ts.minus();
				ts.print();
				// ts.minus();
			}
		};
		thread_plus.start();
		Thread.sleep(1000);
		thread_minus.start();
	}
	
}

Thread:thread_plus
begin plus count=0
Thread:thread_minus
end plus count=1
begin minus count=1
end minus count=0
print count=0

加锁Lock

重入锁ReentrantLock

读写锁ReentrantReadWriteLock

匿名内部类的加锁

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.locks.ReentrantLock;

public class TestAnonymous {

	public static String getNowDateTime() {
		SimpleDateFormat s_format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		Date d_date = new Date();
		String s_date = "";
		s_date = s_format.format(d_date);
		return s_date;
	}

	private static void runSync() {
		for (int i = 0; i < 5; i++) {
			final int pos = i;
			Thread t = new Thread() {
				@Override
				public synchronized void run() {
					try {
						Thread.sleep(1000);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
					System.out.println(getNowDateTime() + " runSync pos=" + pos);
				}
			};
			t.start();
		}
	}

	private final static ReentrantLock lock = new ReentrantLock();

	private static void runLock() {
		for (int i = 0; i < 5; i++) {
			final int pos = i;
			Thread t = new Thread() {
				@Override
				public void run() {
					try {
						lock.lock();
						Thread.sleep(1000);
						System.out.println(getNowDateTime() + " runLock pos=" + pos);
					} catch (InterruptedException e) {
						e.printStackTrace();
					} finally {
						lock.unlock();
					}
				}
			};
			t.start();
		}
	}

	public static void main(String[] args) {
		runSync();
		runLock();
	}

}

2016-04-20 11:25:36 runSync pos=1
2016-04-20 11:25:36 runSync pos=4
2016-04-20 11:25:36 runSync pos=2
2016-04-20 11:25:36 runSync pos=3
2016-04-20 11:25:36 runSync pos=0
2016-04-20 11:25:36 runLock pos=0
2016-04-20 11:25:37 runLock pos=1
2016-04-20 11:25:38 runLock pos=2
2016-04-20 11:25:39 runLock pos=3
2016-04-20 11:25:40 runLock pos=4

Android开发笔记（八十八）同步与加锁

标签：

原文地址：http://blog.csdn.net/aqi00/article/details/51200409