JAVA Set接口

 1 import org.junit.Test;
 2 
 3 import java.util.HashSet;
 4 import java.util.LinkedHashSet;
 5 import java.util.Set;
 6 import java.util.TreeSet;
 7 
 8 public class TestSet {
 9     /*
10         Collection接口：
11         |---Set接口：存储无序，不可重复的元素
12             1，HashSet
13             2,LinkedHashSet
14             3,TreeSet
15             Set的元素是如何保存的：使用了哈希算法
16             向Set中添加对象时：调用hashCode()方法，计算哈希值
17             hashCode()方法要与equals()方法一致
18 
19      */
20     @Test
21     public void testTreeSet1(){
22         Set set =new TreeSet();
23 
24     }
25     @Test
26     public void testLinkedHashSet(){
27         Set set =new LinkedHashSet();
28         set.add(123);
29         set.add("aaa");
30 
31     }
32     @Test
33     public void testHashSet() {
34             //Set无序性：无序性！=随机性
35             //不可重复
36             Set set = new HashSet();
37             set.add(123);
38             set.add("abd");
39             Person p1 =new Person("noo",18);
40             Person p2 =new Person("noo",18);
41             System.out.println(p1.equals(p2));
42             System.out.println(p1.hashCode());
43             System.out.println(p2.hashCode());
44             System.out.println(set.size());
45             set.add(p1);
46             set.add(p2);
47             System.out.println(set);
48     }
49 
50 
51 }

 1 public class Person {
 2     private String name ;
 3     private Integer age ;
 4     public String getName(){
 5         return name;
 6     }
 7     public Integer getAge(){
 8         return age;
 9     }
10     public void setName(){
11         this.name=name;
12     }
13     public void setAge(){
14         this.age=age;
15     }
16     public Person(String name,Integer age){
17         super();
18         this.age=age;
19         this.name=name;
20     }
21     public Person(){
22         super();
23     }
24     @Override
25     public String toString(){
26         return "Person[name="+name+",age="+age+"]";
27     }
28 }