Java ByteBuffer equals()方法及示例

java.nio.ByteBuffer 类的 equals() 方法用于检查给定的缓冲区是否与另一个对象相等。

两个字节缓冲区是相等的，当且仅当。

• 它们具有相同的元素类型。
• 它们有相同数量的剩余元素，并且
• 两个剩余元素的序列，独立于它们的起始位置考虑，是点状相等的。

字节缓冲区不等于任何其他类型的对象。

语法

public boolean equals(Object ob)

参数： 该方法以ob(这个缓冲区要被比较的对象)为参数。

返回值： 当且仅当这个缓冲区等于给定的对象时，该方法返回真。

下面是说明equals()方法的例子。

例子 1 :

// Java program to demonstrate
// equals() method
  
import java.nio.*;
import java.util.*;
  
public class GFG {
  
    public static void main(String[] args)
    {
  
        // Declaring the capacity of the ByteBuffer 1
        int capacity1 = 5;
  
        // Declaring the capacity of the  ByteBuffer 2
        int capacity2 = 5;
  
        // Creating the ByteBuffer
        try {
  
            // creating object of ByteBuffer 1
            // and allocating size capacity
            ByteBuffer bb1 = ByteBuffer.allocate(capacity1);
  
            // creating object of ByteBuffer 2
            // and allocating size capacity
            ByteBuffer bb2 = ByteBuffer.allocate(capacity2);
  
            // putting the int to byte typecast value in ByteBuffer 1
            bb1.put((byte)20);
            bb1.put((byte)30);
            bb1.put((byte)40);
            bb1.rewind();
  
            // putting the value in ByteBuffer 2
            bb2.put((byte)20);
            bb2.put((byte)30);
            bb2.put((byte)40);
            bb2.rewind();
  
            // print the ByteBuffer 1
            System.out.println(" ByteBuffer 1:  "
                               + Arrays.toString(bb1.array()));
  
            // print the ByteBuffer 2
            System.out.println(" ByteBuffer 2:  "
                               + Arrays.toString(bb2.array()));
  
            // checking the equality of both ByteBuffer
            boolean b = bb1.equals(bb2);
  
            // checking if else condition
            if (b)
                System.out.println(" both are equal");
            else
                System.out.println(" both are not equal");
        }
  
        catch (IllegalArgumentException e) {
            System.out.println("Exception thrown : " + e);
        }
  
        catch (ReadOnlyBufferException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

输出。

ByteBuffer 1:  [20, 30, 40, 0, 0]
 ByteBuffer 2:  [20, 30, 40, 0, 0]
 both are equal

例子 2 :

// Java program to demonstrate
// equals() method
  
import java.nio.*;
import java.util.*;
  
public class GFG {
  
    public static void main(String[] args)
    {
  
        // Declaring the capacity of the ByteBuffer 1
        int capacity1 = 5;
  
        // Declaring the capacity of the  ByteBuffer 2
        int capacity2 = 3;
  
        // Creating the ByteBuffer
        try {
  
            // creating object of ByteBuffer 1
            // and allocating size capacity
            ByteBuffer bb1 = ByteBuffer.allocate(capacity1);
  
            // creating object of ByteBuffer 2
            // and allocating size capacity
            ByteBuffer bb2 = ByteBuffer.allocate(capacity2);
  
            // putting the int to byte typecast value in ByteBuffer 1
            bb1.put((byte)20);
            bb1.put((byte)30);
            bb1.put((byte)40);
            bb1.rewind();
  
            // putting the value in ByteBuffer 2
            bb2.put((byte)20);
            bb2.put((byte)30);
            bb2.put((byte)40);
            bb2.rewind();
  
            // print the ByteBuffer 1
            System.out.println(" ByteBuffer 1:  "
                               + Arrays.toString(bb1.array()));
  
            // print the ByteBuffer 2
            System.out.println(" ByteBuffer 2:  "
                               + Arrays.toString(bb2.array()));
  
            // checking the equality of both ByteBuffer
            boolean b = bb1.equals(bb2);
  
            // checking if else condition
            if (b)
                System.out.println(" both are equal");
            else
                System.out.println(" both are not equal");
        }
  
        catch (IllegalArgumentException e) {
            System.out.println("Exception thrown : " + e);
        }
  
        catch (ReadOnlyBufferException e) {
            System.out.println("Exception thrown : " + e);
        }
    }
}

输出。

ByteBuffer 1:  [20, 30, 40, 0, 0]
 ByteBuffer 2:  [20, 30, 40]
 both are not equal