Java中的 FloatBuffer array() 方法及示例

Java.nio.FloatBuffer类的array()方法用于返回支持此缓冲区的浮点数组。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 float[] 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 FloatBuffer
        int capacity = 10;
  
        // Creating the FloatBuffer
        try {
  
            // creating object of floatbuffer
            // and allocating size capacity
            FloatBuffer fb = FloatBuffer.allocate(capacity);
  
            // putting the value in floatbuffer
            fb.put(8.56F);
            fb.put(2, 9.61F);
            fb.rewind();
  
            // getting array from fb FloatBuffer using array() method
            float[] fbb = fb.array();
  
            // printing the FloatBuffer fb
            System.out.println("FloatBuffer:  "
                               + Arrays.toString(fbb));
        }
  
        catch (IllegalArgumentException e) {
  
            System.out.println("IllegalArgumentException catched");
        }
  
        catch (ReadOnlyBufferException e) {
  
            System.out.println("ReadOnlyBufferException catched");
        }
    }
}

输出：

FloatBuffer:  [8.56, 0.0, 9.61, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]

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 fb
        int capacity1 = 10;
  
        // Declaring the capacity of the fb1
        int capacity2 = 5;
  
        // Creating the FloatBuffer
        try {
            //
            // fb
            //
            // creating object of floatbuffer fb
            // and allocating size capacity
            FloatBuffer fb = FloatBuffer.allocate(capacity1);
  
            // putting the value in fb
            fb.put(9.56F);
            fb.put(2, 7.61F);
            fb.put(3, 4.61F);
            fb.rewind();
  
            // print the FloatBuffer
            System.out.println("FloatBuffer fb: "
                               + Arrays.toString(fb.array()));
  
            //
            // fb1
            //
            // creating object of floatbuffer fb1
            // and allocating size capacity
            FloatBuffer fb1 = FloatBuffer.allocate(capacity2);
  
            // putting the value in fb1
            fb1.put(1, 4.56F);
            fb1.put(2, 6.45F);
            fb1.rewind();
  
            // print the FloatBuffer
            System.out.println("\nFloatBuffer fb1:  "
                               + Arrays.toString(fb1.array()));
  
            // Creating a read-only copy of FloatBuffer
            // using asReadOnlyBuffer() method
            FloatBuffer readOnlyFb = fb.asReadOnlyBuffer();
  
            // print the FloatBuffer
            System.out.print("\nReadOnlyBuffer FloatBuffer: ");
  
            while (readOnlyFb.hasRemaining())
                System.out.print(readOnlyFb.get() + ", ");
  
            // try to change readOnlyFb
            System.out.println("\n\nTrying to get the array"
                               + " from ReadOnlyFb for editing");
  
            float[] fbarr = readOnlyFb.array();
        }
        catch (IllegalArgumentException e) {
            System.out.println("IllegalArgumentException catched");
        }
        catch (ReadOnlyBufferException e) {
            System.out.println("Exception thrown: " + e);
        }
    }
}

输出：

FloatBuffer fb: [9.56, 0.0, 7.61, 4.61, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]

FloatBuffer fb1:  [0.0, 4.56, 6.45, 0.0, 0.0]

ReadOnlyBuffer FloatBuffer: 9.56, 0.0, 7.61, 4.61, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 

Trying to get the array from ReadOnlyFb for editing
Exception thrown: java.nio.ReadOnlyBufferException