Java ByteBuffer array()用法及代码示例

java.nio.ByteBuffer类的array()方法用于返回支持采用缓冲区的字节数组。

对该缓冲区内容的修改将导致返回数组的内容被修改，反之亦然。

在调用此方法之前，请先调用hasArray()方法，以确保此缓冲区具有可访问的后备数组。

用法:

public final byte[] array()

返回值：此方法返回支持此缓冲区的数组。

异常：如果此缓冲区由数组支持但为只读，则此方法引发ReadOnlyBufferException。

下面是说明array()方法的示例：

示例1:

// Java program to demonstrate 
// array() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the ByteBuffer 
        int capacity = 4; 
  
        // Creating the ByteBuffer 
        try { 
  
            // creating object of ByteBuffer 
            // and allocating size capacity 
            ByteBuffer bb = ByteBuffer.allocate(capacity); 
  
            // putting the int to byte typecast value in ByteBuffer 
            bb.put((byte)20); 
            bb.put((byte)30); 
            bb.put((byte)40); 
            bb.put((byte)50); 
  
            // print the ByteBuffer 
            System.out.println("ByteBuffer:  "
                               + Arrays.toString(bb.array())); 
  
            // getting byte array from ByteBuffer 
            // using array() method 
            byte[] arr = bb.array(); 
  
            // print the byte array 
            System.out.println("\nbyte array: " +  
                                    Arrays.toString(arr)); 
        } 
  
        catch (IllegalArgumentException e) { 
  
            System.out.println("Exception throws: " + e); 
        } 
    } 
}

输出：

ByteBuffer:  [20, 30, 40, 50]

byte array: [20, 30, 40, 50]

示例2:

// Java program to demonstrate 
// array() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the ByteBuffer 
        int capacity = 4; 
  
        // Creating the ByteBuffer 
        try { 
  
            // creating object of ByteBuffer 
            // and allocating size capacity 
            ByteBuffer bb = ByteBuffer.allocate(capacity); 
  
            // putting the int to byte typcast value 
            // in ByteBuffer 
            bb.put((byte)20); 
            bb.put((byte)30); 
            bb.put((byte)40); 
            bb.put((byte)50); 
            bb.rewind(); 
  
            // print the ByteBuffer 
            System.out.println("Original ByteBuffer:  "
                               + Arrays.toString(bb.array())); 
  
            // Creating a read-only copy of ByteBuffer 
            // using asReadOnlyBuffer() method 
            ByteBuffer bb1 = bb.asReadOnlyBuffer(); 
            bb1.rewind(); 
  
            // print the ByteBuffer 
            System.out.print("\nReadOnlyBuffer ByteBuffer : "); 
  
            while (bb1.hasRemaining()) 
                System.out.print(bb1.get() + ", "); 
  
            // getting byte array from read-only 
            // ByteBuffer using array() method 
            System.out.println("\n\nTrying to get the array"
                               + " from bb1 for editing"); 
            byte[] arr = bb1.array(); 
        } 
  
        catch (IllegalArgumentException e) { 
  
            System.out.println("Exception throws: " + e); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("Exception throws: " + e); 
        } 
    } 
}

输出：

Original ByteBuffer:  [20, 30, 40, 50]

ReadOnlyBuffer ByteBuffer : 20, 30, 40, 50, 

Trying to get the array from bb1 for editing
Exception throws: java.nio.ReadOnlyBufferException

相关用法

注：本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 ByteBuffer array() method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。