Java ShortBuffer asReadOnlyBuffer()方法及示例

java.nio.ShortBuffer 类的 asReadOnlyBuffer() 方法是用来创建一个新的、只读的短缓冲区，其内容是这个缓冲区的。新的缓冲区是这个缓冲区的复制品。因此，对这个缓冲区的内容所做的改变将在新的缓冲区中可见。

由于新缓冲区是只读的，因此不允许对其内容进行任何修改。两个缓冲区的位置、极限和标记值将是独立的。新缓冲区的容量、极限、位置和标记值将与这个缓冲区的相同。如果这个缓冲区本身是只读的，那么这个方法的行为与复制方法完全相同。

语法:

public abstract ShortBuffer asReadOnlyBuffer()

返回值 :该方法返回新的、 只读的短缓冲区 ，其内容与该缓冲区的内容相同。

下面是说明 asReadOnlyBuffer() 方法的例子。

程序1 :

// Java program to demonstrate// asReadOnlyBuffer() method  import java.nio.*;import java.util.*;  public class GFG {      public static void main(String[] args)    {          // Declaring the capacity of the ShortBuffer        int capacity = 10;          // Creating the ShortBuffer        try {              // creating object of shortbuffer            // and allocating size capacity            ShortBuffer sb = ShortBuffer.allocate(capacity);              // putting the value in shortbuffer            sb.put((short)856);            sb.put(2, (short)961);            sb.rewind();              // print the ShortBuffer            System.out.println("Original ShortBuffer: "                               + Arrays.toString(sb.array()));              // Creating a read-only copy of ShortBuffer            // using asReadOnlyBuffer() method            ShortBuffer shortBuffer = sb.asReadOnlyBuffer();              // print the ShortBuffer            System.out.print("\nReadOnlyBuffer ShortBuffer: ");              while (shortBuffer.hasRemaining())                System.out.print(shortBuffer.get() + ", ");        }          catch (IllegalArgumentException e) {            System.out.println("IllegalArgumentException catched");        }          catch (ReadOnlyBufferException e) {            System.out.println("ReadOnlyBufferException catched");        }    }}

输出:

Original ShortBuffer: [856, 0, 961, 0, 0, 0, 0, 0, 0, 0]ReadOnlyBuffer ShortBuffer: 856, 0, 961, 0, 0, 0, 0, 0, 0, 0,

程序2 :

// Java program to demonstrate// asReadOnlyBuffer() method  import java.nio.*;import java.util.*;  public class GFG {    public static void main(String[] args) throws Exception    {          // Declaring the capacity of the sb        int capacity1 = 10;          // Declaring the capacity of the sb1        int capacity2 = 5;          // Creating the ShortBuffer        try {              //            // sb            //            // creating object of shortbuffer sb            // and allocating size capacity            ShortBuffer sb = ShortBuffer.allocate(capacity1);              // putting the value in sb            sb.put((short)856);            sb.put(2, (short)961);            sb.rewind();              // print the ShortBuffer            System.out.println("ShortBuffer sb: "                               + Arrays.toString(sb.array()));              //            // sb1            //            // creating object of shortbuffer sb1            // and allocating size capacity            ShortBuffer sb1 = ShortBuffer.allocate(capacity2);              // putting the value in sb1            sb1.put(1, (short)456);            sb1.put(2, (short)645);            sb1.rewind();              // print the ShortBuffer            System.out.println("\nShortBuffer sb1: "                               + Arrays.toString(sb1.array()));              // Creating a read-only copy of ShortBuffer            // using asReadOnlyBuffer() method            ShortBuffer readOnlySb = sb.asReadOnlyBuffer();              // print the ShortBuffer            System.out.print("\nReadOnlyBuffer FloatBuffer: ");              while (readOnlySb.hasRemaining())                System.out.print(readOnlySb.get() + ", ");              // try to change readOnlySb            System.out.println("\n\nTrying to get the array"                               + " from ReadOnlyFb for editing");              short[] sbarr = readOnlySb.array();        }        catch (IllegalArgumentException e) {            System.out.println("IllegalArgumentException catched");        }        catch (ReadOnlyBufferException e) {            System.out.println("Exception thrown: " + e);        }    }}

输出:

ShortBuffer sb: [856, 0, 961, 0, 0, 0, 0, 0, 0, 0]ShortBuffer sb1: [0, 456, 645, 0, 0]ReadOnlyBuffer FloatBuffer: 856, 0, 961, 0, 0, 0, 0, 0, 0, 0, Trying to get the array from ReadOnlyFb for editingException thrown: java.nio.ReadOnlyBufferException