java利用set给数组去重

hashSet 无序

treeSet 有序（对数据按其默认排序方式，进行排序）

	    @Test
		public void test() throws Exception {
	    	Gson gson = new Gson();
	    	
	    	Set<String> hashSet = new HashSet<String>();
	    	Set<String> treeSet = new TreeSet<String>();
	    	
	    	//初始化数组
	    	String[] keys = new String[20];
	    	for (int i=0; i < 10 ; i++) {
				keys[i] = i+"";
			}
	    	keys[10] = "99";
	    	for (int i=11; i < 20 ; i++) {
	    		keys[i] = (i-10)+"";
	    	}
	    	
	    	hashSet.addAll(Arrays.asList(keys));
	    	treeSet.addAll(Arrays.asList(keys));
	    	
	    	System.out.println(gson.toJson(keys));
	    	//去重，无序
	    	System.out.println(hashSet);
	    	//去重，有序
	    	System.out.println(treeSet);
	    	
	    	//最后再转为数组
	    	System.out.println(gson.toJson(treeSet.toArray()));
	    	
		}

资料：http://simplehumn.iteye.com/blog/812064（详见评论部分）

set介绍：http://www.cnblogs.com/Terry-greener/archive/2011/12/02/2271707.html