ArrayList.sort();自定义比较规则(Lambda表达式)
List<User> userList = new ArrayList<User>(); buildData ( userList ); for (User u : userList ){ System. out .println( u .toString()); } userList . sort ( new Comparator<User>(){ @Override public int compare(User arg0 , User arg1 ) { //这里是根据ID来排序,所以它为空的要剔除掉 if ( arg0 .getId()== null || arg1 .getId()== null ) return 0; return arg0 .getId().compareTo( arg1 .getId()); //这是顺序 } });