字节缓冲区在 Java 中复制()方法，示例
原文:https://www . geeksforgeeks . org/bytebuffer-replicate-method-in-Java-with-examples/
java.nio.ByteBuffer 类的replicate()方法用于创建一个共享该缓冲区内容的新字节缓冲区。
新缓冲区的内容将是该缓冲区的内容。对此缓冲区内容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。
新缓冲区的容量、限制、位置和标记值将与该缓冲区相同。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 ByteBuffer duplicate()
返回值:该方法返回携带前一字节缓冲区内容的新字节缓冲区。
以下是说明复制()方法的示例:
示例 1: 使用直接字节缓冲
// Java program to demonstrate
// duplicate() method
// Using direct ByteBuffer
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 4;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb1 = ByteBuffer.allocate(capacity);
// putting the int to byte typecast value value in ByteBuffer
bb1.put((byte)20);
bb1.put((byte)30);
bb1.put((byte)40);
bb1.put((byte)50);
bb1.rewind();
// print the Original ByteBuffer
System.out.println("Original ByteBuffer: "
+ Arrays.toString(bb1.array()));
// Creating a duplicate copy of ByteBuffer
// using duplicate() method
ByteBuffer bb2 = bb1.duplicate();
// print the duplicate copy of ByteBuffer
System.out.print("\nDuplicate ByteBuffer: "
+ Arrays.toString(bb2.array()));
}
catch (IllegalArgumentException e) {
System.out.println("Exception thrown : " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception thrown : " + e);
}
}
}
Output:
Original ByteBuffer: [20, 30, 40, 50]
Duplicate ByteBuffer: [20, 30, 40, 50]
示例 2: 使用只读字节缓冲区
// Java program to demonstrate
// duplicate() method
// using 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 = 4;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb1 = ByteBuffer.allocate(capacity);
// putting the int to byte typecast value in ByteBuffer
bb1.put((byte)20);
bb1.put((byte)30);
bb1.put((byte)40);
bb1.put((byte)50);
bb1.rewind();
// print the Original ByteBuffer
System.out.println("Original ByteBuffer: "
+ Arrays.toString(bb1.array()));
// Creating a read-only copy of ByteBuffer
// using asReadOnlyBuffer() method
ByteBuffer readonly = bb1.asReadOnlyBuffer();
// print the read-only copy of ByteBuffer
System.out.print("\nRead-only ByteBuffer: ");
while (readonly.hasRemaining())
System.out.print(readonly.get() + ", ");
System.out.println("");
// Rewinding the readonly ByteBuffer
readonly.rewind();
// Creating a duplicate copy of ByteBuffer
// using duplicate() method
ByteBuffer bb2 = readonly.duplicate();
// print the duplicate copy of ByteBuffer
System.out.print("\nDuplicate copy of read-only ByteBuffer: ");
while (bb2.hasRemaining())
System.out.print(bb2.get() + ", ");
System.out.println("");
}
catch (IllegalArgumentException e) {
System.out.println("Exception thrown : " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception thrown : " + e);
}
}
}
Output:
Original ByteBuffer: [20, 30, 40, 50]
Read-only ByteBuffer: 20, 30, 40, 50,
Duplicate copy of read-only ByteBuffer: 20, 30, 40, 50,
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