如何使用Java实现比较HalamanAlamat类不同实例对象属性值的matches静态方法

Got it, let's build that matches method you need. The goal is to check if every property of two HalamanAlamat objects is identical, returning 1 if they all match and 0 otherwise. Here's how to do it properly:

Key Notes First #

• For string properties (name, address, email), always use equals() instead of ==. The == operator checks if two strings point to the same object in memory, while equals() compares the actual text content.
• We need to handle null values for string properties to avoid NullPointerException.
• Also, your original nbInstance variable is an instance field—this means every HalamanAlamat object has its own copy, so it won't correctly count total instances. I'll fix that to be a static variable since it should track all instances created.

Complete Modified Code #

class HalamanAlamat {
    private String name;
    private String address;
    private int phone;
    private String email;
    // Make nbInstance static to track all instances globally
    private static int nbInstance;

    HalamanAlamat(){
        this.name = "null";
        this.address = "null";
        this.phone = 0;
        this.email = "null";
        // No need for "this" since it's static
        nbInstance++;
    }

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

    void setAddress(String address){
        this.address = address;
    }

    void setPhone(int phone){
        this.phone = phone;
    }

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

    String getName(){
        return this.name;
    }

    String getAddress(){
        return this.address;
    }

    int getPhone(){
        return this.phone;
    }

    String getEmail(){
        return this.email;
    }

    // Fixed method name to follow Java conventions (toString instead of tostring)
    public void toString(){
        System.out.println("Nama : " + getName());
        System.out.println("Alamat : " + getAddress());
        System.out.println("No.Handphone : " + getPhone());
        System.out.println("Email : " + getEmail());
    }
}

public class BukuAlamat {
    // The required static matches method
    public static int matches(HalamanAlamat halamanA1, HalamanAlamat halamanA2) {
        // Handle null object cases first
        if (halamanA1 == null && halamanA2 == null) {
            return 1;
        }
        if (halamanA1 == null || halamanA2 == null) {
            return 0;
        }

        // Compare each property, handling null strings
        boolean nameMatches = (halamanA1.getName() == null && halamanA2.getName() == null)
                || (halamanA1.getName() != null && halamanA1.getName().equals(halamanA2.getName()));
        boolean addressMatches = (halamanA1.getAddress() == null && halamanA2.getAddress() == null)
                || (halamanA1.getAddress() != null && halamanA1.getAddress().equals(halamanA2.getAddress()));
        boolean phoneMatches = halamanA1.getPhone() == halamanA2.getPhone();
        boolean emailMatches = (halamanA1.getEmail() == null && halamanA2.getEmail() == null)
                || (halamanA1.getEmail() != null && halamanA1.getEmail().equals(halamanA2.getEmail()));

        // Return 1 if all properties match, else 0
        return (nameMatches && addressMatches && phoneMatches && emailMatches) ? 1 : 0;
    }

    public static void main(String[] args) {
        HalamanAlamat halaman1 = new HalamanAlamat();
        halaman1.setName("Rizki okto");
        halaman1.setAddress("Ambarita");
        halaman1.setPhone(629768328);
        halaman1.setEmail("rizok@gmail.com");
        halaman1.toString();

        // Test case 1: Identical object
        HalamanAlamat halaman2 = new HalamanAlamat();
        halaman2.setName("Rizki okto");
        halaman2.setAddress("Ambarita");
        halaman2.setPhone(629768328);
        halaman2.setEmail("rizok@gmail.com");
        System.out.println("\nMatch result (identical): " + matches(halaman1, halaman2)); // Should print 1

        // Test case 2: Different phone number
        HalamanAlamat halaman3 = new HalamanAlamat();
        halaman3.setName("Rizki okto");
        halaman3.setAddress("Ambarita");
        halaman3.setPhone(123456789);
        halaman3.setEmail("rizok@gmail.com");
        System.out.println("Match result (different phone): " + matches(halaman1, halaman3)); // Should print 0
    }
}

How It Works #

1. Null Handling: We first check if either or both objects are null to avoid errors when accessing properties.
2. Property Comparison:
   • For strings: Check if both are null, or if neither is null and their contents match via equals().
   • For integers (phone): Directly use == since it's a primitive type.
3. Return Value: If all properties match, return 1; otherwise, return 0.

I also fixed a small convention issue: renamed tostring() to toString() to follow Java naming standards (capital 'T').

内容的提问来源于stack exchange，提问作者Tomoro