Collections.sort

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Collections.sort进行排序

User user = new User();user.setUserName("zhangsan");user.setUserId("111");user.setIndex(0);User user1 = new User();user1.setUserName("lisi");user1.setUserId("222");user1.setIndex(1);User user2 = new User();user2.setUserName("wangwu");user2.setUserId("333");user2.setIndex(2);List list = new ArrayList();list.add(user2);list.add(user1);list.add(user);Collections.sort(list,new Comparator<User>(){@Overridepublic int compare(User o1, User o2) {if(o1.getIndex()>o2.getIndex()){return 1;}else if(o1.getIndex()<o2.getIndex()){return -1;}return 0;}});for(Iterator it = list.iterator();it.hasNext();){Object obj = it.next();if(obj instanceof User){User u = (User) obj;System.out.println(u.getUserName());}}

重写Comparator接口的compare方法

一般是在类中定义一个内部类

static class IntegerComparator implements Comparator{@Overridepublic int compare(Object o1, Object o2) {return Integer.valueOf(o1.toString()).compareTo(Integer.valueOf(o2.toString()));}}

然后在使用的时候直接这样使用

Collections.sort(list,new IntegerComparator());

就可以了

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