1 import java.util.ArrayList;
  2 import java.util.Scanner;
  3 
  4 public class Main {
  5 
  6     public static void main(String[] args) {
  7         // 通过Scanner可以从控制台读取用户输入的数据
  8         Scanner scanner = new Scanner(System.in);
  9         ArrayList<Student> list = new ArrayList<Student>();
 10 
 11         while (true) {
 12             // Unreachable code
 13             System.out.println("请输入id：");
 14             int id = scanner.nextInt();
 15             System.out.println("请输入名字:");
 16             String name = scanner.next();
 17             System.out.println("请输入年龄：");
 18             int age = scanner.nextInt();
 19             System.out.println("请输入性别:");
 20             String gender = scanner.next();
 21             Student student = new Student(id, name, age, gender);
 22             list.add(student);
 23 
 24             System.out.println("您是否要退出： -1退出, 0继续");
 25             int quit = scanner.nextInt();
 26             if (quit == -1) {
 27                 break;
 28             }
 29         }
 30 
 31         for (Student student : list) {
 32             System.out.println(student);
 33         }
 34 
 35         while (true) {
 36             System.out.println("-------------------------");
 37             System.out.println("根据id搜索输入1");
 38             System.out.println("根据name搜索输入2");
 39             System.out.println("根据age搜索输入3");
 40             System.out.println("根据gender搜索输入4");
 41             System.out.println("您是否要退出： -1退出, 0继续");
 42             System.out.println("-------------------------");
 43             int type = scanner.nextInt();
 44             if (type == -1) {
 45                 System.out.println("退出程序");
 46                 break;
 47             }
 48             boolean search = false;//未找到该学生
 49             switch (type) {
 50             case 1:// 根据id搜索
 51                 System.out.println("请输入要搜索的id");
 52                 int id = scanner.nextInt();
 53                 for (Student student : list) {
 54                     if (id == student.getId()) {
 55                         System.out.println(student);
 56                         search = true;
 57                     }
 58                 }
 59                 if(search == false) {
 60                     System.out.println("没有该id的学生");
 61                 }
 62                 break;
 63             case 2:// 根据name搜索
 64                 System.out.println("请输入要搜索的名字：");
 65                 String name = scanner.next();
 66                 for (Student student : list) {
 67                     // 在java里面判断字符串的内容是不是相等使用equal的方法
 68                     if (name.equals(student.getName())) {
 69                         System.out.println(student);
 70                         search = true;
 71                     }
 72                 }
 73                 if(search == false) {
 74                     System.out.println("没有该名字的学生");
 75                 }
 76                 break;
 77             case 3:// 根据age搜索
 78                 System.out.println("请输入要搜索的年龄");
 79                 int age = scanner.nextInt();
 80                 for (Student student : list) {
 81                     if (age == student.getAge()) {
 82                         System.out.println(student);
 83                         search = true;
 84                     }
 85                 }
 86                 if(search == false) {
 87                     System.out.println("没有该年龄的学生");
 88                 }
 89                 break;
 90             case 4:// 根据gender搜索
 91                 System.out.println("请输入要搜索的性别：");
 92                 String gender = scanner.next();
 93                 for (Student student : list) {
 94                     // 在java里面判断字符串的内容是不是相等使用equal的方法
 95                     if (gender.equals(student.getGender())) {
 96                         System.out.println(student);
 97                         search = true;
 98                     }
 99                 }
100                 if(search == false) {
101                     System.out.println("没有该性别的学生");
102                 }
103                 break;
104 
105             default:
106                 break;
107             }
108         }
109 
110     }
111 }

 1 public class Student {
 2     private int id;
 3     private String name;
 4     public int age;
 5     private String gender;
 6 
 7     public int getId() {
 8         return id;
 9     }
10 
11     public void setId(int id) {
12         this.id = id;
13     }
14 
15     public String getName() {
16         return name;
17     }
18 
19     public Student(int id, String name, int age, String gender) {
20         super();
21         this.id = id;
22         this.name = name;
23         this.age = age;
24         this.gender = gender;
25     }
26 
27     public void setName(String name) {
28         this.name = name;
29     }
30 
31     public Student() {
32         super();
33         // TODO Auto-generated constructor stub
34     }
35 
36     public int getAge() {
37         return age;
38     }
39 
40     public void setAge(int age) {
41         this.age = age;
42     }
43 
44     public String getGender() {
45         return gender;
46     }
47 
48     public void setGender(String gender) {
49         this.gender = gender;
50     }
51 
52     @Override
53     public String toString() {
54         return "Student [id=" + id + ", name=" + name + ", age=" + age + ", gender=" + gender + "]";
55     }
56 }