Java 中的 ByteBuffer asFloatBuffer()方法,示例

原文:https://www . geeksforgeeks . org/bytebuffer-as float buffer-method-in-Java-with-examples/

java.nio.ByteBuffer 类的 asFloatBuffer() 方法用于创建该字节缓冲区作为浮动缓冲区的视图。 新缓冲区的内容将从该缓冲区的当前位置开始。对此缓冲区内容所做的更改将在新缓冲区中可见,反之亦然;两个缓冲器的位置、极限和标记值将是独立的。 新缓冲区的位置将为零,其容量和限制将是该缓冲区中剩余的字节数除以 4,其标记将是未定义的。如果且仅当该缓冲区是直接的,则新缓冲区将是直接的;如果且仅当该缓冲区是只读的,则新缓冲区将是只读的。

语法:

public abstract FloatBuffer asFloatBuffer()

返回值:这个方法返回一个新的浮点缓冲区

下面是说明 asFloatBuffer()方法的示例:

实施例 1:

Java 语言(一种计算机语言,尤用于创建网站)

// 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);
        }
    }
}

Output: 

FloatBuffer : 1.23 1.33 1.56

实施例 2:

Java 语言(一种计算机语言,尤用于创建网站)

// 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);
        }
    }
}

Output: 

FloatBuffer : 2.1  3.1  4.1  

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