Java ByteBuffer asFloatBuffer()方法及实例

java.nio.ByteBuffer 类的 asFloatBuffer() 方法用于将此字节缓冲区创建为浮点缓冲区的视图。

新缓冲区的内容将从此缓冲区的当前位置开始。对这个缓冲区的内容所做的改变将在新的缓冲区中可见，反之亦然；两个缓冲区的位置、极限和标记值将是独立的。

新缓冲区的位置将是0，其容量和极限将是这个缓冲区中剩余的字节数除以4，其标记将是未定义的。当且仅当这个缓冲区是直接的，新的缓冲区将是直接的，当且仅当这个缓冲区是只读的，它将是只读的。

语法

public abstract FloatBuffer asFloatBuffer()

返回值： 该方法返回一个新的浮点数缓冲区

下面是说明asFloatBuffer()方法的例子。

例子 1 :

// Java program to demonstrate
// asFloatBuffer() method
// for ByteBuffer
 
import java.nio.*;
import java.util.*;
 
public class GFG {
 
    public static void main(String[] args)
    {
 
        // Declaring the capacity  of the ByteBuffer
        int capacity = 50;
 
        // Creating the ByteBuffer
        try {
 
            // creating object of  ByteBuffer
            // and allocating size capacity
            ByteBuffer bb = ByteBuffer.allocate(capacity);
 
            // changing  bytebuffer into
            // FloatBuffer
            FloatBuffer cb = bb.asFloatBuffer();
 
            // putting the value in FloatBuffer
            cb.put(1.23F);
            cb.put(1.33F);
            cb.put(1.56F);
            cb.rewind();
 
            // Declaring variable c
            Float c;
 
            // print the ByteBuffer
            System.out.print("FloatBuffer : ");
            while ((c = cb.get()) != 0)
                System.out.print(c + " ");
        }
 
        catch (IllegalArgumentException e) {
 
            System.out.println("Exception thrown : " + e);
        }
 
        catch (ReadOnlyBufferException e) {
 
            System.out.println("Exception thrown : " + e);
        }
    }
}

输出

FloatBuffer : 1.23 1.33 1.56

例子 2 :

// Java program to demonstrate
// asFloatBuffer() method
// for Read only ByteBuffer
 
import java.nio.*;
import java.util.*;
 
public class GFG {
 
    public static void main(String[] args)
    {
 
        // Declaring the capacity  of the ByteBuffer
        int capacity = 50;
 
        // Creating the ByteBuffer
        try {
 
            // creating object of  ByteBuffer
            // and allocating size capacity
            ByteBuffer bb = ByteBuffer.allocate(capacity);
 
            // changing  bytebuffer into
            // FloatBuffer
            FloatBuffer cb = bb.asFloatBuffer();
 
            // putting the value in FloatBuffer
            cb.put(2.1F);
            cb.put(3.1F);
            cb.put(4.1F);
            cb.rewind();
 
            // Declaring variable c
            Float c;
 
            // print the ByteBuffer
            System.out.print("FloatBuffer : ");
            while ((c = cb.get()) != 0)
                System.out.print(c + "  ");
 
            // Creating a read-only copy of ByteBuffer
            // using asReadOnlyBuffer() method
            ByteBuffer bb1 = bb.asReadOnlyBuffer();
 
            // changing read-only bytebuffer into
            // read-only FloatBuffer
            FloatBuffer cb1 = bb1.asFloatBuffer();
 
            // putting the value in read-only FloatBuffer
            System.out.println("\n\nTrying to put the value "
                               + "in read only FloatBuffer");
            cb1.put(2.1F);
            cb1.put(3.1F);
            cb1.put(4.1F);
            cb1.rewind();
        }
 
        catch (IllegalArgumentException e) {
 
            System.out.println("Exception thrown : " + e);
        }
 
        catch (ReadOnlyBufferException e) {
 
            System.out.println("Exception thrown : " + e);
        }
    }
}

输出

FloatBuffer : 2.1  3.1  4.1  

Trying to put the value in read only FloatBuffer
Exception thrown : java.nio.ReadOnlyBufferException