Java中的IntBuffer asReadOnlyBuffer（）方法-yiteyi-C++库

这个 asReadOnlyBuffer（） 方法 JAVA尼奥。IntBuffer类 用于创建 新的只读int缓冲区 用这个缓冲区的内容。新缓冲区是此缓冲区的副本。因此，对该缓冲区内容所做的更改将在新缓冲区中可见。

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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。两个缓冲器的位置、极限和标记值将是独立的。新缓冲区的容量、限制、位置和标记值将与此缓冲区的相同。如果此缓冲区本身是只读的，则此方法的行为方式与复制方法完全相同。

语法：

public abstract IntBuffer asReadOnlyBuffer()

返回值： 此方法返回 新的只读int缓冲区 与此缓冲区的内容相同。

下面是演示asReadOnlyBuffer（）方法的示例：

例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 IntBuffer                   
                                         int                               capacity =                               10                               ;                   
                             
                                         // Creating the IntBuffer                   
                                         try                               {                   
                             
                                         // creating object of Intbuffer                   
                                         // and allocating size capacity                   
                                         IntBuffer ib = IntBuffer.allocate(capacity);                   
                             
                                         // putting the value in Intbuffer                   
                                         ib.put(                               8                               );                   
                                         ib.put(                               2                               ,                               9                               );                   
                                         ib.rewind();                   
                             
                                         // print the IntBuffer                   
                                         System.out.println(                               "Original IntBuffer:  "                   
                                         + Arrays.toString(ib.array()));                   
                             
                                         // Creating a read-only copy of IntBuffer                   
                                         // using asReadOnlyBuffer() method                   
                                         IntBuffer IntBuffer = ib.asReadOnlyBuffer();                   
                             
                                         // print the IntBuffer                   
                                         System.out.print(                               "ReadOnlyBuffer IntBuffer: "                               );                   
                             
                                         while                               (IntBuffer.hasRemaining())                   
                                         System.out.print(IntBuffer.get() +                               ", "                               );                   
                                         }                   
                             
                                         catch                               (IllegalArgumentException e) {                   
                                         System.out.println(                               "IllegalArgumentException catched"                               );                   
                                         }                   
                             
                                         catch                               (ReadOnlyBufferException e) {                   
                                         System.out.println(                               "ReadOnlyBufferException catched"                               );                   
                                         }                   
                                         }                   
                     }                   

输出：

Original IntBuffer:  [8, 0, 9, 0, 0, 0, 0, 0, 0, 0]

ReadOnlyBuffer IntBuffer: 8, 0, 9, 0, 0, 0, 0, 0, 0, 0,

例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 ib                   
                                         int                               capacity1 =                               10                               ;                   
                             
                                         // Declaring the capacity of the ib1                   
                                         int                               capacity2 =                               5                               ;                   
                             
                                         // Creating the IntBuffer                   
                                         try                               {                   
                             
                                         // creating object of Intbuffer ib                   
                                         // and allocating size capacity                   
                                         IntBuffer ib = IntBuffer.allocate(capacity1);                   
                             
                                         // putting the value in ib                   
                                         ib.put(                               8                               );                   
                                         ib.put(                               2                               ,                               9                               );                   
                                         ib.rewind();                   
                             
                                         // print the IntBuffer                   
                                         System.out.println(                               "IntBuffer ib: "                   
                                         + Arrays.toString(ib.array()));                   
                             
                                         // ib1                   
                                         // creating object of Intbuffer ib1                   
                                         // and allocating size capacity                   
                                         IntBuffer ib1 = IntBuffer.allocate(capacity2);                   
                             
                                         // putting the value in ib1                   
                                         ib1.put(                               1                               ,                               4                               );                   
                                         ib1.put(                               2                               ,                               6                               );                   
                                         ib1.rewind();                   
                             
                                         // print the IntBuffer                   
                                         System.out.println(                               "IntBuffer ib1:  "                   
                                         + Arrays.toString(ib1.array()));                   
                             
                                         // Creating a read-only copy of IntBuffer                   
                                         // using asReadOnlyBuffer() method                   
                                         IntBuffer readOnlyib = ib.asReadOnlyBuffer();                   
                             
                                         // print the IntBuffer                   
                                         System.out.print(                               "ReadOnlyBuffer IntBuffer: "                               );                   
                             
                                         while                               (readOnlyib.hasRemaining())                   
                                         System.out.print(readOnlyib.get() +                               ", "                               );                   
                             
                                         // try to change readOnlyib                   
                                         System.out.println(                               "Trying to get the array"                   
                                         +                               " from ReadOnlyib for editing"                               );                   
                             
                                         int                               [] ibarr = readOnlyib.array();                   
                                         }                   
                             
                                         catch                               (IllegalArgumentException e) {                   
                                         System.out.println(                               "IllegalArgumentException catched"                               );                   
                                         }                   
                             
                                         catch                               (ReadOnlyBufferException e) {                   
                                         System.out.println(                               "Exception thrown: "                               + e);                   
                                         }                   
                                         }                   
                     }                   

输出：

IntBuffer ib: [8, 0, 9, 0, 0, 0, 0, 0, 0, 0]

IntBuffer ib1:  [0, 4, 6, 0, 0]

ReadOnlyBuffer IntBuffer: 8, 0, 9, 0, 0, 0, 0, 0, 0, 0, 

Trying to get the array from ReadOnlyib for editing
Exception thrown: java.nio.ReadOnlyBufferException

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