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Java FloatBuffer wrap()用法及代码示例


wrap(float[] array)

java.nio.FloatBuffer类的wrap()方法用于将float数组包装到缓冲区中。新缓冲区将由给定的float数组支持;也就是说,对缓冲区的修改将导致数组被修改,反之亦然。新缓冲区的容量和限制为array.length,位置为零,标记未定义。它的支持数组将是给定的数组,其数组偏移量将为零。

用法:

public static FloatBuffer wrap(float[] array)

参数:此方法将array(将支持此缓冲区的数组)作为参数。


返回值:此方法返回新的浮点缓冲区。

下面是说明wrap()方法的示例:

范例1:

// Java program to demonstrate 
// asReadOnlyBuffer() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // Declare and initialize the float array 
        float[] fbb = { 1.23F, 2.34F, 4.56F }; 
  
        // print the float array length 
        System.out.println("Array length : " + fbb.length); 
  
        // print the float array element 
        System.out.println("\nArray element : "
                           + Arrays.toString(fbb)); 
  
        // wrap the float array into floatBuffer 
        // using wrap() method 
        FloatBuffer floatBuffer = FloatBuffer.wrap(fbb); 
  
        // Rewind the floatbuffer 
        floatBuffer.rewind(); 
  
        // print the float buffer 
        System.out.println("\nfloatBuffer : "
                           + Arrays.toString(floatBuffer.array())); 
  
        // print the FloatBuffer capacity 
        System.out.println("\nfloatbuffer capacity : "
                           + floatBuffer.capacity()); 
  
        // print the FloatBuffer position 
        System.out.println("\nfloatbuffer position:  "
                           + floatBuffer.position()); 
    } 
}
输出:
Array length : 3

Array element : [1.23, 2.34, 4.56]

floatBuffer : [1.23, 2.34, 4.56]

floatbuffer capacity : 3

floatbuffer position:  0

wrap(float[] array, int offset, int length)

新缓冲区将由给定的float数组支持;也就是说,对缓冲区的修改将导致数组被修改,反之亦然。新缓冲区的容量将为array.length,其位置将偏移,其限制将为offset + length,其标记将是不确定的。它的支持数组将是给定的数组,其数组偏移量将为零。

用法:

public static FloatBuffer wrap (float[] array, int offset, int length)

参数:此方法采用以下参数:

  • array:将支持新缓冲区的数组。
  • offset:要使用的子数组的偏移量;必须为非负数,且不得大于array.length。新缓冲区的位置将设置为此值。
  • length:要使用的子数组的长度;必须为非负且不大于array.length –偏移量。新缓冲区的限制将设置为偏移量+长度。

返回值:此方法返回新的浮点缓冲区。

抛出:此方法抛出IndexOutOfBoundsException(如果offset和length参数的前提条件不成立)。

下面是说明wrap()方法的示例:

范例1:

// Java program to demonstrate 
// asReadOnlyBuffer() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declare and initialize the float array 
        float[] fbb = { 1.23F, 2.34F, 4.56F }; 
  
        // print the float array length 
        System.out.println("Array length : " + fbb.length); 
  
        // print the float array element 
        System.out.println("\nArray element : "
                           + Arrays.toString(fbb)); 
  
        // wrap the float array into floatBuffer 
        // using wrap() method 
        FloatBuffer floatBuffer = FloatBuffer.wrap(fbb, 0, 
                                                   fbb.length); 
  
        // Rewind the floatbuffer 
        floatBuffer.rewind(); 
  
        // print the float buffer 
        System.out.println("\nfloatBuffer : "
                           + Arrays.toString(floatBuffer.array())); 
  
        // print the FloatBuffer capacity 
        System.out.println("\nfloatbuffer capacity : "
                           + floatBuffer.capacity()); 
  
        // print the FloatBuffer position 
        System.out.println("\nfloatbuffer position:  "
                           + floatBuffer.position()); 
    } 
}
输出:
Array length : 3

Array element : [1.23, 2.34, 4.56]

floatBuffer : [1.23, 2.34, 4.56]

floatbuffer capacity : 3

floatbuffer position:  0

范例2:演示NullPointerException

// Java program to demonstrate 
// asReadOnlyBuffer() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declare and initialize the float array 
        float[] fbb = { 1.23F, 2.34F, 4.56F }; 
  
        // print the float array length 
        System.out.println("Array length : " + fbb.length); 
  
        // print the float array element 
        System.out.println("\nArray element : " + Arrays.toString(fbb)); 
  
        try { 
            // wrap the float array into floatBuffer 
            // using wrap() method 
            System.out.println("\nHere "
                               + "offset and length does not hold"
                               + " the required condition "); 
            FloatBuffer floatBuffer = FloatBuffer.wrap(fbb, 
                                                       1, 
                                                       fbb.length); 
  
            // Rewind the floatbuffer 
            floatBuffer.rewind(); 
  
            // print the float buffer 
            System.out.println("\nfloatBuffer : "
                               + Arrays.toString(floatBuffer.array())); 
  
            // print the FloatBuffer capacity 
            System.out.println("\nfloatbuffer capacity : "
                               + floatBuffer.capacity()); 
  
            // print the FloatBuffer position 
            System.out.println("\nfloatbuffer position:  "
                               + floatBuffer.position()); 
        } 
        catch (IndexOutOfBoundsException e) { 
            System.out.println("Exception throws:  " + e); 
        } 
    } 
}
输出:
Array length : 3

Array element : [1.23, 2.34, 4.56]

Here offset and length does not hold the required condition 
Exception throws:  java.lang.IndexOutOfBoundsException


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注:本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 FloatBuffer wrap() method in Java with Examples。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。