组合两个if语句

Question

我只允许在我的主菜单中有4个选项，我创建了5个。我不知道如何把最后2个输出语句放在一起，这样一个语句就可以从另一个语句的内部调用。因此它们可以使用相同的菜单选项。

选项3和选项4需要以某种方式在彼此内部，这样我就可以显示输入的所有联系人的名称，然后提示用户选择联系人ID，以显示该联系人的其余详细信息。

package ooo1;

import java.util.ArrayList;
import java.util.Scanner;

public class ContactList {

    public static void main(String[] args) {

        ArrayList<Contact> contacts = new ArrayList<>();

        Scanner input1 = new Scanner(System.in);
        int type = 0;
        while(type != 5){
        System.out.println("Please select an option: ");
        System.out.println("Add a Personal Contact: Enter 1 ");
        System.out.println("Add a Business Contact: Enter 2 ");
        System.out.println("Display Contacts List: Enter 3 ");
        System.out.println("Display Contact Details: Enter 4 ");
        System.out.println("To Quit: Enter 5 ");

        type = input1.nextInt();

        if(type == 5){
            System.out.println("Goodbye ");
            break;
        }
 if (type == 1 || type == 2){

         Contact contact = null;

        Scanner input = new Scanner(System.in);
        System.out.println("Please enter ContactId : ");
        String contactId = input.nextLine();
        System.out.println("Please enter First Name : ");
        String firstName = input.nextLine();
        System.out.println("Please enter Last Name : ");
        String lastName = input.nextLine();
        System.out.println("Please enter Address in the following format : ");
        System.out.println("Street Address, City, State, Zip Code");
        String address = input.nextLine();
        System.out.println("Please enter Phone Number : ");
        String phoneNumber = input.nextLine();
        System.out.println("Please enter Email Address : ");
        String emailAddress = input.nextLine();

        //Create a personal contact.
        if(type == 1){
           System.out.println("Please enter Birthday: ");
           String dateofBirth = input.nextLine();
           Contact pcontact = new PersonalContact(contactId, firstName, lastName, address, phoneNumber, emailAddress, dateofBirth);
           contacts.add(pcontact);
           System.out.println("Contact Added Successfully");
           System.out.println();
        }
        //Create a business contact.
        else if(type == 2){
            System.out.println("Please enter Job Title: ");
            String jobTitle = input.nextLine();
            System.out.println("Please enter Organization: ");
            String organization = input.nextLine();
            Contact bcontact = new BusinessContact(contactId, firstName, lastName, address, phoneNumber, emailAddress, jobTitle, organization);
            contacts.add(bcontact);
            System.out.println("Contact Added Successfully");
            System.out.println();
        }

    }
    if (type == 3 || type == 4){

        //Print full name of each Contact.
        if(type == 3){
            for (Contact namecontact: contacts)
            {
                System.out.println(namecontact.displayFullName());
                System.out.println();
            }
        } 
        //Print contact details for selected contact.
        else if(type == 4){
                System.out.println("Enter a Contact ID to display Contact Details: ");
                Scanner input2 = new Scanner(System.in);
                String soughtID;
                soughtID = input2.nextLine();
            for (Contact showcontact1: contacts)
                {
                   if (showcontact1.displayId().equals(soughtID))
                    System.out.println(showcontact1.displayContact());
                   System.out.println();
                }
            }
         }
      }
  }
}

package ooo1;

public abstract class Contact {

    String contactId;
    String firstName;
    String lastName;
    String address;
    String phoneNumber;
    String emailAddress;

    public Contact(String contactId,String firstName,String lastName, String address, String phoneNumber, String emailAddress)
    {
        this.contactId = contactId;
        this.firstName = firstName;
        this.lastName = lastName;
        this.address = address;
        this.phoneNumber = phoneNumber;
        this.emailAddress = emailAddress;
    }
    public void setContactId(String input){
        this.contactId = input;
    }
    public String getContactId(){
        return contactId;
    }

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

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

    public void setAddress(String input){
        this.address = input;
    }
    public String getAddress(){
        return address;
    }

    public void setPhoneNumber(String input){
        this.phoneNumber = input;
    }
    public String getPhoneNumber(){
        return phoneNumber;
    }

    public void setEmailAddress(String input){
        this.emailAddress = input;
    }
    public String getEmailAddress(){
        return emailAddress;
    }

    @Override
    public String toString(){
       return ("ContactID: " + this.getContactId() + "\nFirst Name: " + this.getFirstName() + "\nLast Name: " + this.getLastName() + "\nAddress: " + this.getAddress() + "\nPhone Number: " + this.getPhoneNumber() + "\nEmail Address " + this.getEmailAddress());
    }

    public String displayFullName(){
        return ("ContactID: " + this.getContactId() + "\nFirst Name: " + this.getFirstName() + "\nLast Name: " + this.getLastName());
    }

    public String displayContact(){
        return ("ContactID: " + this.getContactId() + "\nFirst Name: " + this.getFirstName() + "\nLast Name: " + this.getLastName() + "\nAddress :" + this.getAddress() + "\nPhone Number :" + this.getPhoneNumber() + "\nEmail Address " + this.getEmailAddress());
    }
    public String displayId(){
        return (this.getContactId());
    }          
}

以下是更改前的输出结果和更改后的输出结果。

这是我之前的改变，这是好的，除了我在主菜单中有太多的选项。

请选择一个选项：添加个人联系人：输入1添加业务联系人：输入2显示联系人列表：输入3显示联系人详细信息：输入4退出：输入5 3联系人：2名：汤姆姓：琼斯

输入联系人ID以显示联系人详细信息：12个人联系人：Contactid：12名：Tom姓：Hones地址：234 south st电话号码：234-232-2356电子邮件地址:[e-mail]出生日期：12-12-45

联系人：1名：简姓：史密斯

Answer 1

因此，如果我理解正确，您希望嵌套选项3和4，以便选项3显示所有联系人，然后提供显示特定联系人的选择：

// Other menu code here...
System.out.println("Query Contacts: Enter 3");
System.out.println("To Quit: Enter 4");

// Other code here...

// Bring up sub-menu
// Feel free to extend to return to main menu etc.
if (type == 3){
    while (true) {
       System.out.println("List Contacts: Enter 1");
       System.out.println("Display Contact Details: Enter 2");
       System.out.println("To Quit: Enter 3");

       // If you need, store in another int etc.
       type = input1.nextInt();

       //Print full name of each Contact.
       if (type == 1) {
          for (Contact namecontact: contacts) {
             System.out.println(namecontact.displayFullName());
             System.out.println();
          }
       }
       //Print contact details for selected contact.
       else if(type == 2){
          System.out.println("Enter a Contact ID to display Contact Details: ");
          Scanner input2 = new Scanner(System.in);
          String soughtID;
          soughtID = input2.nextLine();

          for (Contact showcontact1: contacts) {
              // Although correct, I'd recommend you add a braces for if statements
              // Saving a line for a closing brace is not generally worth it
              if (showcontact1.displayId().equals(soughtID))
                 System.out.println(showcontact1.displayContact());
              System.out.println();
          }
       } else if (type == 3) {
          break;
       }
    }
}