ReadWriteLock读写锁

ReadWriteLock 读写锁：多读单写

public class LockTest {
ReadWriteLock lockTreeMap = new ReentrantReadWriteLock();
final TreeMap<Long, String> treeMap = new TreeMap<Long, String>();

public static void main(String[] args) {
LockTest lock = new LockTest();

lock.new TestThread().start();
lock.new TestThread().start();
lock.new TestThread().start();
lock.new TestThread().start();
lock.new TestThread().start();
lock.new TestThread().start();
}

class TestThread extends Thread{
public TestThread(){
}
public void run(){
test();
}
}

void test(){
int loop = 16;
        for (int i = 0; i < loop; i++) {
            String msg = null;
            try {
                lockTreeMap.readLock().lockInterruptibly();
                try {
                    if (!treeMap.isEmpty()) {
                        msg = treeMap.firstEntry().getValue();
                    } else {
                        break;
                    }
                } finally {
                    lockTreeMap.readLock().unlock();
                }
            } catch (InterruptedException e) {

            }
        }
       
        System.out.println("***");
        try {
            lockTreeMap.writeLock().lockInterruptibly();
            try {
                if (!treeMap.isEmpty()) {
                    System.out.println("...");
                }
            } finally {
                lockTreeMap.writeLock().unlock();
            }
        } catch (InterruptedException e) {
        }
}
}