2009年9月23日随笔档案 - 晒太阳

java线程互锁演示

1 /**
2  * 线程互锁：线程td1得到obj1的锁，线程td2得到了obj2的锁，接着，线程td1在持有obj1的锁的同时
3  * 企图得到obj2的锁，而此时线程td2仍持有obj2的锁，所以线程td1等待，而线程td2的行为也与线程td1相同
4  * 因此就形成了死锁
5  */
6 public class Client {
7     public static void main(String[] args) {
8         final Object obj1 = "test1";
9         final Object obj2 = "test2";
10
11         Thread td1 = new Thread(){
12             public void run(){
13                 synchronized(obj1){
14                     System.out.println("td1得到了obj1的锁");
15                     try {
16                         Thread.sleep(1000);
17                     } catch (InterruptedException e) {
18                         e.printStackTrace();
19                     }
20
21                     synchronized(obj2){
22                         System.out.println("td1企图得到obj2的锁");
23
24                         try {
25                             Thread.sleep(1000);
26                         } catch (InterruptedException e) {
27                             e.printStackTrace();
28                         }
29                     }
30                 }
31             }
32         };
33
34
35         Thread td2 = new Thread(){
36             public void run(){
37                 synchronized(obj2){
38                     System.out.println("td2得到了obj2的锁");
39                     try {
40                         Thread.sleep(1000);
41                     } catch (InterruptedException e) {
42                         e.printStackTrace();
43                     }
44
45                     synchronized(obj1){
46                         System.out.println("td2企图得到obj1的锁");
47
48                         try {
49                             Thread.sleep(1000);
50                         } catch (InterruptedException e) {
51                             e.printStackTrace();
52                         }
53                     }
54                 }
55             }
56         };
57
58         td1.start();
59         td2.start();
60     }
61
62 }

posted @ 2012-11-23 06:16 晒太阳阅读(356) | 评论 (0) | 编辑收藏

java 快速排序

1
2 public class QuickSort {
3     public static int partition(int[] arr, int low, int high){
4         int pivot = arr[low];
5         while(low<high){
6             while(low<high && arr[high]>=pivot){
7                 high--;
8             }
9             if(low<high){
10                 arr[low] = arr[high];
11                 low++;
12             }
13
14             while(low<high && arr[low]<=pivot){
15                 low++;
16             }
17             if(low<high){
18                 arr[high] = arr[low];
19                 high--;
20             }
21         }
22         arr[low] = pivot;
23         return low;
24     }
25
26     public static void sort(int[] arr, int low, int high){
27         int pivot;
28         if(low<high){
29             pivot = partition(arr,low,high);
30             sort(arr,low,pivot-1);
31             sort(arr,pivot+1,high);
32         }
33     }
34
35     public static void quickSort(int[] arr){
36         sort(arr,0,arr.length-1);
37     }
38
39     /*public static void main(String[] args) {
40         int[] arr = {46,34,2,99,6,23,20,8};
41         quickSort(arr);
42         StringBuilder sb = new StringBuilder();
43         for(int i=0;i<arr.length;i++){
44             sb.append(arr[i]+",");
45         }
46         sb.deleteCharAt(sb.length()-1);
47         System.out.println(sb);
48     }*/
49 }
50

posted @ 2012-11-01 12:06 晒太阳阅读(101) | 评论 (0) | 编辑收藏