代码
@Test
void sort05(){
List<Integer> list = new ArrayList<Integer>();
list.add(new Integer(5));
list.add(new Integer(13));
list.add(new Integer(4));
list.add(new Integer(9));
Collections.sort(list);
System.out.println(list.toString());
//对数字进行排序
List<Integer> nums = Arrays.asList(3,1,5,2,9,8,4,10,6,7);
nums.sort(Comparator.reverseOrder()); //reverseOrder倒序
System.err.println("倒序:"+nums);
nums.sort(Comparator.naturalOrder()); //naturalOrder自然排序即:正序
System.err.println("正序:"+nums);
User user0 = new User(1,"jack","6");
User user1 = new User(1,"jack","9");
User user2 = new User(1,"jack","5");
User user3 = new User(1,"jack","3");
ArrayList<User> users = new ArrayList<>();
users.add(user0);
users.add(user1);
users.add(user2);
users.add(user3);
// users.sort((o1, o2)->o1.getPassword().compareTo(o2.getPassword()));
//users.sort(Comparator.comparing(User::getPassword));
//第六写法,个Lambda写法,JAVA8的写法
Comparator<User> ageComparator = (o1, o2)->o1.getPassword().compareTo(o2.getPassword());
//users.sort(ageComparator); //按上面配置的顺序取值
users.sort(ageComparator.reversed()); //按上面配置的顺序反向取值
for (User u:users) {
System.out.println(u);
}
}
参考文章
https://my.oschina.net/sdlvzg/blog/2243766
对象List单属性排序
List<Developer> listDevs = ComparatorTest.getDevelopers();
System.out.println("排序前:");
//JAVA8的写法,循环
listDevs.forEach((developer)->System.out.println(developer));
//第一个写法
Collections.sort(listDevs, new Comparator<Developer>() {
@Override
public int compare(Developer o1, Developer o2) {
return o1.getAge().compareTo(o2.getAge());
}
});
//第二个写法,JAVA8的写法,List 接口支持直接使用 sort 该方法,不再需要使用 Collections.sort 了
//listDevs.sort(listDevs, new Comparator<Developer>() {
// @Override
// public int compare(Developer o1, Developer o2) {
// return o1.getAge().compareTo(o2.getAge();
// }
//});
//第三个写法,Lambda写法,JAVA8的写法
//listDevs.sort((Developer o1, Developer o2)->o1.getAge().compareTo(o2.getAge()));
//第四个写法,Lambda写法,JAVA8的写法
//listDevs.sort((o1, o2)->o1.getAge().compareTo(o2.getAge()));
//第五写法,个Lambda写法,JAVA8的写法
//listDevs.sort(Comparator.comparing(Developer::getAge));
//第六写法,个Lambda写法,JAVA8的写法
Comparator<Developer> ageComparator = (o1, o2)->o1.getAge().compareTo(o2.getAge());
listDevs.sort(ageComparator); //按上面配置的顺序取值
listDevs.sort(ageComparator.reversed()); //按上面配置的顺序反向取值
System.out.println("排序后:");
//JAVA8的写法,循环
listDevs.forEach((developer)->System.out.println(developer));