两个线程与stringbuffer和stringbuiler以及lock synchronized线程测试

 1 import java.util.concurrent.locks.Lock;
 2 import java.util.concurrent.locks.ReentrantLock;
 3 
 4 public  class RunnableTest2 {
 5 //    private StringBuilder sb = new StringBuilder();
 6     private StringBuffer sb = new StringBuffer();
 7     inc i1 = new inc();
 8     dec d1 = new dec();
 9     private Lock lock = new ReentrantLock();
10     private boolean ok = false;
11     public static void main(String[] args) throws InterruptedException {
12         RunnableTest2 tr = new RunnableTest2();
13         double time = System.currentTimeMillis();
14         for(int i=0;i<1;i++) {
15             new Thread(tr.i1).start();
16             new Thread(tr.d1).start();
17             
18         }
19 //        System.out.println(System.currentTimeMillis()-time);
20     }
21     
22     private  void incc() {
23 //        synchronized(sb) {
24         lock.lock();
25         for(int i=0;i<7;i++) {
26             char at = "freedom".charAt(i);
27             sb.append(at+"");
28             
29         }
30         
31            System.out.println(Thread.currentThread().getName()+sb.toString()); 
32            sb.delete(0, 7);
33 //        }
34            lock.unlock();
35     }
36     
37     private  void decc() {
38 //        synchronized(sb) {
39         lock.lock();
40 
41         for(int i=0;i<7;i++) {
42             char at = "freedom".charAt(i);
43             sb.append(at+"");
44             
45         }
46         
47            System.out.println(Thread.currentThread().getName()+sb.toString()); 
48            sb.delete(0, 7);
49 //        }
50            lock.unlock();
51 
52     }
53     
54     class inc implements Runnable {
55         public void run() {
56             // TODO Auto-generated method stub
57             for(int i=0; i<100000; i++)
58             incc();
59         }
60     }
61 
62     class dec implements Runnable {
63         public void run() {
64             // TODO Auto-generated method stub
65             for(int i=0; i<100000; i++)
66             decc();
67         }
68     }
69 }

打印结果各有不同