在Java中創建具有唯一ID的列表並對其進行操作

Question

我想創建一個程序來創建一個看起來像這樣的列表

ID: 1
Name: Example
Surname: Example
email: example

//New list

ID: 2
Name: Example
Surname: Example
email: example

然后當我想更改某些內容（例如Name：）時，我想通過id進行更改，因此只能在ID為2的列表內進行更改

Answer 1

您應該使用HashMap 。

創建一個包含ID，名稱，姓氏和電子郵件實例變量的類（將其歸類為YourClass ）。

然后創建一個HashMap ，其中鍵是標識符，值是YourClass ：

Map<Integer,YourClass> map = new HashMap<>();
map.put(objectOfYourClassWithID1.getID(),objectOfYourClassWithID1);
map.put(objectOfYourClassWithID2.getID(),objectOfYourClassWithID2);
if (map.containsKey(2)) {
    map.get(2).setSomeProperty(newValue); // this will only change the object whose ID is 2
}

Answer 2

你可以像這樣創建類

public class Record{
    private int id;
    private String name;
    private String Surname;
    private String email;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSurname() {
        return Surname;
    }

    public void setSurname(String surname) {
        Surname = surname;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }
}

然后像這樣使用它：

    Record record1 = new Record();
    record1.setId(1);
    record1.setName("example");
    record1.setSurname("example");
    record1.setEmail("example");

    Record record2 = new Record();
    record2.setId(2);
    record2.setName("example");
    record2.setSurname("example");
    record2.setEmail("example");

    Map<Integer,Record> recordMap = new HashMap<Integer, Record>();
    recordMap.put(record1.getId(),record1);
    recordMap.put(record2.getId(),record2);]

    recordMap.get(2).getName();//example
    recordMap.get(2).setName("ebi");
    recordMap.get(2).getName();//ebi

Answer 3

import java.util.ArrayList;
import java.util.List;

public class Person {

private int id;
private String name;
private String Surname;
private String email;

public Person(int id, String name, String surname, String email) {
    super();
    this.id = id;
    this.name = name;
    Surname = surname;
    this.email = email;
}

public int getId() {
    return id;
}

public void setId(int id) {
    this.id = id;
}

public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getSurname() {
    return Surname;
}

public void setSurname(String surname) {
    Surname = surname;
}

public String getEmail() {
    return email;
}

public void setEmail(String email) {
    this.email = email;
}

public static void main(String[] args) {

    List<Person> list = new ArrayList<Person>();
    list.add(new Person(1, "example", "example", "example"));
    list.add(new Person(2, "example", "example", "example"));
  }

 }