java自定义排序的俩种方法

1.Comparator 定制排序

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Collections.sort(arrayList, new Comparator<Integer>() {             @Override             public int compare(Integer o1, Integer o2) {                 return o1.compareTo(o2);             }         });

2.compare接口重写 compareTo 方法

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public  class Person implements Comparable<Person>{     @Override     public int compareTo(Person o) {         if (this.age > o.getAge()) {             return 1;         }         if (this.age < o.getAge()) {             return -1;         }         return 0;     } }

3.传入匿名内部类的方法：

其实还是上面那俩种，只不过使用了匿名内部类

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TreeMap<Person, String> treeMap = new TreeMap<>(new Comparator<Person>() {            @Override            public int compare(Person person1, Person person2) {                int num = person1.getAge() - person2.getAge();                return Integer.compare(num, 0);            }        });