Java Java.util.Arrays.equals()用法及代碼示例

今天，我們將討論檢查兩個數組是否相等的最簡單方法。如果兩個數組包含相同數量的元素，並且兩個數組中所有對應的元素對均相等，則認為兩個數組相等。換句話說，如果兩個數組包含相同順序的相同元素，則它們相等。另外，如果兩個數組引用都為空，則認為它們相等。

Java中的Arrays類提供了Arrays.equals()方法來檢查兩個數組是否相等。

用法:
public static boolean equals(int[] a, int[] a2)
參數:
a - one array to be tested for equality
a2 - the other array to be tested for equality
返回:
true if the two arrays are equal

其他變體：

公共靜態布爾值equals(byte [] a，byte [] a2)
公共靜態布爾值equals(short [] a，short [] a2)
公共靜態布爾值equals(long [] a，long [] a2)
公共靜態布爾值equals(float [] a，float [] a2)
公共靜態布爾值equals(double [] a，double [] a2)
公共靜態布爾值equals(char [] a，char [] a2)
公共靜態布爾值等於(boolean [] a，boolean [] a2)
公共靜態布爾值equals(Object [] a，Object [] a2)

// Java program to demonstrate working of Arrays.equals() 
  
import java.util.Arrays; 
  
public class ArrayEqualDemo  
{ 
    public static void main(String[] args)  
    { 
        // Let us create different integers arrays 
        int[] arr1 = new int [] {1, 2, 3, 4}; 
        int[] arr2 = new int [] {1, 2, 3, 4}; 
        int[] arr3 = new int [] {1, 2, 4, 3}; 
          
        System.out.println("is arr1 equals to arr2:" + 
                                Arrays.equals(arr1, arr2)); 
        System.out.println("is arr1 equals to arr3:" + 
                                Arrays.equals(arr1, arr3)); 
    } 
}

輸出：

is arr1 equals to arr2:true
is arr1 equals to arr3:false

我們也可以使用陣列.equals()用於檢查用戶定義的類的對象數組的相等性。陣列.equals()方法

注意：-如果是對象數組，則必須重寫equals方法以提供自己的相等性定義，否則，將根據Object類的equals()方法返回的內容獲得輸出。在下麵的程序中，我們將檢查學生的rollno，姓名和地址是否相等。

// Java program to demonstrate working of Arrays.equals() 
// for user defined objects. 
  
import java.util.Arrays; 
   
  
public class ArrayEqualDemo 
{ 
    public static void main (String[] args) 
    { 
        Student [] arr1 = {new Student(111, "bbbb", "london"), 
                           new Student(131, "aaaa", "nyc"), 
                           new Student(121, "cccc", "jaipur")}; 
          
        Student [] arr2 = {new Student(111, "bbbb", "london"), 
                           new Student(131, "aaaa", "nyc"), 
                           new Student(121, "cccc", "jaipur")}; 
          
        Student [] arr3 = {new Student(111, "bbbb", "london"), 
                           new Student(121, "dddd", "jaipur"), 
                           new Student(131, "aaaa", "nyc"), 
                           }; 
          
        System.out.println("is arr1 equals to arr2:" + 
                                    Arrays.equals(arr1, arr2)); 
        System.out.println("is arr1 equals to arr3:" + 
                                    Arrays.equals(arr1, arr3));     
    }     
} 
   
// A class to represent a student. 
class Student 
{ 
    int rollno; 
    String name, address; 
   
    // Constructor 
    public Student(int rollno, String name, 
                               String address) 
    { 
        this.rollno = rollno; 
        this.name = name; 
        this.address = address; 
    } 
      
    @Override
    public boolean equals(Object obj) { 
          
        // typecast obj to Student so that we can compare students 
        Student s = (Student) obj; 
          
        return this.rollno == s.rollno && this.name.equals(s.name) 
                                && this.address.equals(s.address); 
    } 
}

輸出：

is arr1 equals to arr2:true
is arr1 equals to arr3:false

相關用法

注：本文由純淨天空篩選整理自 Java.util.Arrays.equals() in Java with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。