1 import java.util.ArrayList;
2 import java.util.List;
3
4 public class ArrayList_Test {
5 public static void main(String[] args) {
6 List<Student> stus = new ArrayList<>();
7
8 stus.add(new Student("zhangsan"));
9 stus.add(new Student("lisi"));
10 stus.add(new Student("zhangsan"));
11 stus.add(new Student("zhangsan"));
12 stus.add(new Student("wangwu"));
13 // 第一种
14 // for (int i = 0; i < stus.size() - 1; i++) {
15 // for (int j = i + 1; j < stus.size()-1; j++) {
16 // if (stus.get(i).getName().equals(stus.get(j).getName())) {
17 // stus.remove(stus.get(i));
18 // }
19 // }
20 // }
21 // System.out.println(stus);
22 // 第二种
23 // 定义一个新集合
24 List<Student> stus2 = new ArrayList<>();
25 for (int i = 0; i < stus.size(); i++) {
26 if (!stus2.contains(stus.get(i))) {// 内部调用了equals方法，所以比的是栈中的引用地址，所以要重写equals方法
27 stus2.add(stus.get(i));
28 }
29 }
30 System.out.println(stus2);
31
32 }
33 }
34
35 class Student {
36 String name;
37
38 public Student(String name) {
39 this.name = name;
40 }
41
42 public String getName() {
43 return name;
44 }
45
46 public void setName(String name) {
47 this.name = name;
48 }
49
50 @Override
51 public String toString() {
52 return "Student [name=" + name + "]";
53 }
54
55 @Override
56 public int hashCode() {
57 final int prime = 31;
58 int result = 1;
59 result = prime * result + ((name == null) ? 0 : name.hashCode());
60 return result;
61 }
62
63 @Override
64 public boolean equals(Object obj) {
65 if (this == obj)
66 return true;
67 if (obj == null)
68 return false;
69 if (getClass() != obj.getClass())
70 return false;
71 Student other = (Student) obj;
72 if (name == null) {
73 if (other.name != null)
74 return false;
75 } else if (!name.equals(other.name))
76 return false;
77 return true;
78 }
79
80 }
