TreeSet---使用匿名内部类创建比较器添加元素

 1 import java.util.Comparator;
 2 import java.util.Iterator;
 3 import java.util.TreeSet;
 4
 5
 6 public class Test2
 7 {
 8     public static void main(String[] args)
 9     {
10         TreeSet<Person> set = new TreeSet<>(new Comparator<Person>() {
11
12             @Override
13             public int compare(Person o1, Person o2)
14             {
15                 int  result;
16                 result = o1.getAge()-o2.getAge();
17                 if(result==0) {
18                     result = o1.getName().compareTo(o2.getName());
19                 }
20                 return result;
21             }
22         });
23        Person p1 = new Person("剑魔",20);
24        Person p2 = new Person("剑姬",20);
25        Person p3 = new Person("剑豪",20);
26        Person p4 = new Person("剑圣",20);
27        set.add(p1);
28        set.add(p2);
29        set.add(p3);
30        set.add(p4);
31      Iterator<Person> iterator = set.iterator();
32      while(iterator.hasNext()) {
33          System.out.println(iterator.next());
34      }
35     }
36 }

自定义一个类

 1 public class Person
 2 {
 3     private String name;
 4     private int age;
 5     public String getName()
 6     {
 7         return name;
 8     }
 9     public void setName(String name)
10     {
11         this.name = name;
12     }
13     public int getAge()
14     {
15         return age;
16     }
17     public void setAge(int age)
18     {
19         this.age = age;
20     }
21     public Person(String name, int age)
22     {
23         super();
24         this.name = name;
25         this.age = age;
26     }
27     public Person()
28     {
29         super();
30     }
31     @Override
32     public String toString()
33     {
34         return "Person [name=" + name + ", age=" + age + "]";
35     }
36     @Override
37     public int hashCode()
38     {
39         final int prime = 31;
40         int result = 1;
41         result = prime * result + age;
42         result = prime * result + ((name == null) ? 0 : name.hashCode());
43         return result;
44     }
45     @Override
46     public boolean equals(Object obj)
47     {
48         if (this == obj)
49             return true;
50         if (obj == null)
51             return false;
52         if (getClass() != obj.getClass())
53             return false;
54         Person other = (Person) obj;
55         if (age != other.age)
56             return false;
57         if (name == null)
58         {
59             if (other.name != null)
60                 return false;
61         }
62         else if (!name.equals(other.name))
63             return false;
64         return true;
65     }
66
67 }