Java中的 LongBuffer hasArray() 方法

Java.nio.LongBuffer类的array()方法用于返回支持此缓冲区的Long 数组。对此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。 Invoke() hasArray() 方法在调用此方法之前使用，以确保此缓冲区具有可访问的后备数组

句法 ：

public final Long[] array()

返回值：此方法返回支持此缓冲区的数组。

抛出：此方法抛出ReadOnlyBufferException （如果此缓冲区由数组支持但为只读）

下面的程序说明了array()方法：

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 LongBuffer
        int capacity = 10;
  
        // Creating the LongBuffer
        try {
  
            // creating object of Longbuffer
            // and allocating size capacity
            LongBuffer ib = LongBuffer.allocate(capacity);
  
            // putting the value in Longbuffer
            ib.put(7);
            ib.put(2, 6);
            ib.rewind();
  
            // getting array from ib LongBuffer using array() method
            long[] ibb = ib.array();
  
            // prLonging the LongBuffer ib
            System.out.println("LongBuffer:  "
                               + Arrays.toString(ibb));
        }
  
        catch (IllegalArgumentException e) {
  
            System.out.println("IllegalArgumentException catched");
        }
  
        catch (ReadOnlyBufferException e) {
  
            System.out.println("ReadOnlyBufferException catched");
        }
    }
}

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 ib
        int capacity1 = 10;
  
        // Declaring the capacity of the ib1
        int capacity2 = 5;
  
        // Creating the LongBuffer
        try {
            //
            // ib
            //
            // creating object of Longbuffer ib
            // and allocating size capacity
            LongBuffer ib = LongBuffer.allocate(capacity1);
  
            // putting the value in ib
            ib.put(7);
            ib.put(2, 6);
            ib.put(3, 7);
            ib.rewind();
  
            // prLong the LongBuffer
            System.out.println("LongBuffer ib: "
                               + Arrays.toString(ib.array()));
  
            //
            // ib1
            //
            // creating object of Longbuffer ib1
            // and allocating size capacity
            LongBuffer ib1 = LongBuffer.allocate(capacity2);
  
            // putting the value in ib1
            ib1.put(1, 4);
            ib1.put(2, 6);
            ib1.rewind();
  
            // prLong the LongBuffer
            System.out.println("\nLongBuffer ib1:  "
                               + Arrays.toString(ib1.array()));
  
            // Creating a read-only copy of LongBuffer
            // using asReadOnlyBuffer() method
            LongBuffer readOnlyib = ib.asReadOnlyBuffer();
  
            // prLong the LongBuffer
            System.out.print("\nReadOnlyBuffer LongBuffer: ");
  
            while (readOnlyib.hasRemaining())
                System.out.print(readOnlyib.get() + ", ");
  
            // try to change readOnlyib
            System.out.println("\n\nTrying to get the array"
                               + " from ReadOnlyib for editing");
  
            long[] ibarr = readOnlyib.array();
        }
        catch (IllegalArgumentException e) {
            System.out.println("IllegalArgumentException catched");
        }
        catch (ReadOnlyBufferException e) {
            System.out.println("Exception thrown: " + e);
        }
    }
}