1. package days8;
   
2. 
   
3. import java.util.*;
   
4. 
   
5. class Person implements Comparable
   
6. {
   
7. private String name;
   
8. private int age;
   
9. Person(String name,int age)
   
10. {
    
11. this.name=name;
    
12. this.age=age;
    
13. }
    
14. 
    
15. public String getName()
    
16. {
    
17. return name;
    
18. }
    
19. 
    
20. public int getAge()
    
21. {
    
22. return age;
    
23. }
    
24. 
    
25. 
    
26. public int compareTo(Object obj) {
    
27. 
    
28. 
    
29. if(!(obj instanceof Person))
    
30. throw new RuntimeException("不是学生对象");
    
31. Person s = (Person)obj;
    
32. 
    
33. System.out.println(this.name+"....compareto....."+s.name);
    
34. if(this.age>s.age)
    
35. return 1;
    
36. if(this.age==s.age)
    
37. {
    
38. return this.name.compareTo(s.name);
    
39. }
    
40. return -1;
    
41. }
    
42. 
    
43. 
    
44. 
    
45. }
    
46. 
    
47. public class TreeSet2
    
48. {
    
49. public static void main(String[]args)
    
50. {
    
51. TreeSet al=new TreeSet();
    
52. al.add(new Person("Ben",15));
    
53. al.add(new Person("Ann",12));
    
54. al.add(new Person("Bob",14));
    
55. al.add(new Person("Sam",16));
    
56. 
    
57. Iterator it=al.iterator();
    
58. while(it.hasNext())
    
59. {
    
60. Object obj=it.next();
    
61. Person p=(Person)obj;
    
62. sop(p.getName()+"::"+p.getAge());
    
63. }
    
64. }
    
65. 
    
66. public static void sop(Object obj)
    
67. {
    
68. System.out.println(obj);
    
69. }
    
70. }
    

复制代码

运行结果：
Ann....compareto.....Ben
Bob....compareto.....Ben
Bob....compareto.....Ann
Sam....compareto.....Bob
Sam....compareto.....Ben
Ann::12
Bob::14
Ben::15
Sam::16

求教这部分是怎么得来的，我看jdk手册看了半天，没看明白
Ann....compareto.....Ben
Bob....compareto.....Ben
Bob....compareto.....Ann
Sam....compareto.....Bob
Sam....compareto.....Ben

为什么是这样的比较？？？

突然自己想明白了，二叉树原理呀