Java ~ 用户一个用户

Question

我希望用户通过扫描仪提供数据并将其添加到列表中。稍后，我想获取此列表的大小，例如用户名、姓氏。我仍在尝试使用构造函数和异常，现在我想尝试从用户输入数据。

检查构造函数的是Human Service，如果name少于3个字母，lastname少于5个字母会抛出异常。

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

public class HumanService {
    List<Human> humans;

    public HumanService() {
        humans = new ArrayList<>();
    }

    public void addHuman(String name, String lastName) throws HumanNameWrongFormat, HumanLastNameWrongFormat {
        if(HumanValidator.humanValidatorName(name) && HumanValidator.humanValidatorLastName(lastName)) {
            Human human = new Human(sizeOfList(), name, lastName);
            humans.add(human);
        }
    }

    public int sizeOfList() {
        return humans.size();
    }

    public Human getHumanByLastName(String lastName) throws HumanNotFoundException {
        for (Human human : humans) {
            if (human.getLastName().equals(lastName)) {
                return human;
            }
        }
        throw new HumanNotFoundException(lastName + " not found");
    }

    public Human getHumanById (Integer id) throws HumanNotFoundException {
        for (Human human : humans) {
            if (human.getId().equals(id)) {
                return human;
            }
        }
        throw new HumanNotFoundException(id + " not found");
    }
}

我想按用户列表获取数据。例如。请告诉我你的名字和姓氏。这是您的名字和姓氏，通过扫描仪将被添加到列表中并进行检查。

这也是我的主要class。

public class main {

    public static void main(String[] args) throws HumanNotFoundException {
        HumanService humanService = new HumanService();

        try {
            humanService.addHuman("John", "Walker");
            humanService.addHuman("Steve", "Williams");
            humanService.addHuman("Gregor", "Wroten");
        }
        catch (HumanNameWrongFormat | HumanLastNameWrongFormat e) {
            System.out.println(e.getMessage());
        }

        System.out.println(humanService.sizeOfList());

        try {
            humanService.getHumanByLastName("Wroten");
        }
        catch (HumanNotFoundException e) {
            System.out.println(e.getMessage());
        }
    }
}

Answer 1

这里是您可以使用 Scanner 获取所有必需的用户名并将它们添加到列表以供进一步处理的方法

public class Test {

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);

        List<Human> humans = new ArrayList();

        while (true) {
            System.out.println("Please give your first name");
            String firstName = scanner.nextLine();
            System.out.println("Please give your last name");
            String lastName = scanner.nextLine();
            humans.add(new Human(firstName, lastName)); // use your humanService here
            boolean breakOut = false;
            String input;
            do {
                System.out.println("Do you want to enter more names? (Y/N)");
                input = scanner.nextLine();
                if (input.equalsIgnoreCase("Y") || input.equalsIgnoreCase("N")) {
                    breakOut = true;
                } else {
                    System.out.println("Invalid input. try again");
                }
            } while (!breakOut);
            if (input.equalsIgnoreCase("Y")) {
                break;
            }
        }
        System.out.println(humans);
    }
}

我假设您在 Human

中有两个字段 firstName、lastName

class Human {
    private String firstName;
    private String lastName;

    public Human(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    @Override
    public String toString() {
        return "first name " + firstName + " and last name " + lastName;
    }
}

输入：

Please give your first name
John
Please give your last name
Smith
Do you want to enter more names? (Y/N)
y
Please give your first name
Will
Please give your last name
Smith
Do you want to enter more names? (Y/N)
n

输出：

[first name John and last name Smith, first name Will and last name Smith]

在上面的代码中，replacelist用你的humanService加上humans

Java ~ 用户一个用户

Java ~ User by user

java

list

java.util.scanner