Java IntBuffer wrap()用法及代碼示例

wrap(int[] array)

java.nio.IntBuffer類的wrap()方法用於將int數組包裝到緩衝區中。新緩衝區將由給定的int數組支持；也就是說，對緩衝區的修改將導致數組被修改，反之亦然。新緩衝區的容量和限製為array.length，位置為零，標記未定義。它的支持數組將是給定的數組，其數組偏移量將為零。

用法:

public static IntBuffer wrap(int[] array)

參數：此方法將要支持此緩衝區的數組array作為參數。

返回值：此方法返回創建的新的int緩衝區。

下麵是說明wrap()方法的示例：

範例1：

// Java program to demonstrate 
// wrap() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // Declare and initialize the int array 
        int[] ibb = { 1, 2, 3 }; 
  
        // print the int array length 
        System.out.println("Array length : "
                           + ibb.length); 
  
        // print the int array element 
        System.out.println("\nArray element : "
                           + Arrays.toString(ibb)); 
  
        // wrap the int array into intBuffer 
        // using wrap() method 
        IntBuffer intBuffer = IntBuffer.wrap(ibb); 
  
        // Rewind the intbuffer 
        intBuffer.rewind(); 
  
        // print the int buffer 
        System.out.println("\nintBuffer : "
                           + Arrays.toString(intBuffer.array())); 
  
        // print the IntBuffer capacity 
        System.out.println("\nintbuffer capacity : "
                           + intBuffer.capacity()); 
  
        // print the IntBuffer position 
        System.out.println("\nintbuffer position:  "
                           + intBuffer.position()); 
    } 
}

輸出：

Array length : 3

Array element : [1, 2, 3]

intBuffer : [1, 2, 3]

intbuffer capacity : 3

intbuffer position:  0

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

wrap()方法將int數組包裝到緩衝區中。新緩衝區將由給定的int數組支持；也就是說，對緩衝區的修改將導致數組被修改，反之亦然。新緩衝區的容量將為array.length，其位置將偏移，其限製將為offset + length，其標記將是不確定的。它的支持數組將是給定的數組，其數組偏移量將為零。

用法:

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

參數：此方法采用以下參數：

array:將支持新緩衝區的數組。
offset:要使用的子數組的偏移量；必須為非負數，且不得大於array.length。新緩衝區的位置將設置為此值。
length:要使用的子數組的長度；必須為非負且不大於array.length –偏移量。新緩衝區的限製將設置為偏移量+長度。

返回值：此方法返回新的浮點緩衝區。

引發：如果offset和length參數的前提條件不成立，則此方法引發IndexOutOfBoundsException。

下麵是說明wrap()方法的示例：

範例1：

// Java program to demonstrate 
// wrap() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declare and initialize the int array 
        int[] ibb = { 1, 2, 3 }; 
  
        // print the int array length 
        System.out.println("Array length : " + ibb.length); 
  
        // print the int array element 
        System.out.println("\nArray element : "
                           + Arrays.toString(ibb)); 
  
        // wrap the int array into intBuffer 
        // using wrap() method 
        IntBuffer intBuffer = IntBuffer.wrap(ibb, 0, 
                                             ibb.length); 
  
        // Rewind the intbuffer 
        intBuffer.rewind(); 
  
        // print the int buffer 
        System.out.println("\nintBuffer : "
                           + Arrays.toString(intBuffer.array())); 
  
        // print the IntBuffer capacity 
        System.out.println("\nintbuffer capacity : "
                           + intBuffer.capacity()); 
  
        // print the IntBuffer position 
        System.out.println("\nintbuffer position: "
                           + intBuffer.position()); 
    } 
}

輸出：

Array length : 3

Array element : [1, 2, 3]

intBuffer : [1, 2, 3]

intbuffer capacity : 3

intbuffer position: 0

範例2：演示NullPointerException

// Java program to demonstrate 
// wrap() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declare and initialize the float array 
        int[] ibb = { 1, 2, 3 }; 
  
        // print the int array length 
        System.out.println("Array length : "
                           + ibb.length); 
  
        // print the int array element 
        System.out.println("\nArray element : "
                           + Arrays.toString(ibb)); 
  
        try { 
            // wrap the int array into intBuffer 
            // using wrap() method 
            System.out.println("\nHere "
                               + "offset and length does not hold"
                               + " the required condition "); 
  
            IntBuffer intBuffer = IntBuffer.wrap(ibb, 
                                                 1, 
                                                 ibb.length); 
  
            // Rewind the intbuffer 
            intBuffer.rewind(); 
  
            // print the int buffer 
            System.out.println("\nintBuffer : "
                               + Arrays.toString(intBuffer.array())); 
  
            // print the IntBuffer capacity 
            System.out.println("\nintbuffer capacity : "
                               + intBuffer.capacity()); 
  
            // print the IntBuffer position 
            System.out.println("\nintbuffer position:  "
                               + intBuffer.position()); 
        } 
        catch (IndexOutOfBoundsException e) { 
            System.out.println("Exception throws:  " + e); 
        } 
    } 
}

輸出：

Array length : 3

Array element : [1, 2, 3]

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

相關用法

注：本文由純淨天空篩選整理自nitin_sharma大神的英文原創作品 IntBuffer wrap() method in Java。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。