Java Buffer hasArray()方法及示例

来源：这里教程网时间：2026-02-17 20:37:14 作者：

Java Buffer hasArray()方法及示例

java.nio.Buffer 类的 hasArray() 方法是用来告诉这个缓冲区是否有一个可访问的数组作为支持。如果该方法返回真，那么可以安全地调用数组和arrayOffset()方法。语法

public abstract boolean hasArray()

返回： 当且仅当这个缓冲区是由一个数组支持的并且不是只读的时候，这个方法将返回 true 。否则，它返回 false 下面是说明 hasArray() 方法的例子：

例子1： 当缓冲区由一个数组支持时

// Java program to demonstrate// hasArray() method import java.nio.*;import java.util.*; public class GFG {    public static void main(String[] args)    {         // Declaring the capacity of the ByteBuffer        int capacity = 10;         // Creating the ByteBuffer        try {             // creating object of bytebuffer            // and allocating size capacity            ByteBuffer bb = ByteBuffer.allocate(capacity);             // putting the value in bytebuffer            bb.put((byte)10);            bb.put((byte)20);            bb.rewind();             // Typecast bytebuffer to Buffer            Buffer buffer = (Buffer)bb;             // checking buffer is backed by array or not            boolean isArray = buffer.hasArray();             // checking if else condition            if (isArray)                System.out.println("buffer is"                                   + " backed by array");            else                System.out.println("buffer is"                                   + " not backed by any array");        }         catch (IllegalArgumentException e) {            System.out.println("IllegalArgumentException catched");        }         catch (ReadOnlyBufferException e) {            System.out.println("ReadOnlyBufferException catched");        }    }}

输出

buffer is backed by array

例子2： 当缓冲区没有数组支持的时候

// Java program to demonstrate// hasArray() method import java.nio.*;import java.util.*; public class GFG {     public static void main(String[] args)    {         // Declaring the capacity of the ByteBuffer        int capacity = 10;         // Creating the ByteBuffer        try {             // creating object of ByteBuffer            // and allocating size capacity            ByteBuffer bb = ByteBuffer.allocate(capacity);             // putting the value in ByteBuffer            bb.put((byte)8.56F);            bb.put((byte)10);            bb.rewind();             // Creating a read-only copy of ByteBuffer            // using asReadOnlyBuffer() method            ByteBuffer bb1 = bb.asReadOnlyBuffer();             // Typecast read-only ByteBuffer to read-only buffer            Buffer buffer = (Buffer)bb1;             // checking buffer is backed by array or not            boolean isArray = buffer.hasArray();             // checking if else condition            if (isArray)                System.out.println("buffer is"                                   + " backed by array");            else                System.out.println("buffer is"                                   + " not backed by any array");        }         catch (IllegalArgumentException e) {            System.out.println("IllegalArgumentException catched");        }         catch (ReadOnlyBufferException e) {            System.out.println("ReadOnlyBufferException catched");        }    }}

输出