java.nio.FloatBuffer类的duplicate()方法用于创建共享给定缓冲区内容的新浮点缓冲区。

新缓冲区的内容就是该缓冲区的内容。对该缓冲区内容的更改将在新缓冲区中可见，反之亦然；这两个缓冲区的位置，限制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相同。当且仅当该缓冲区是直接缓冲区时，新缓冲区才是直接缓冲区；当且仅当该缓冲区是只读缓冲区时，新缓冲区才是只读缓冲区。

用法:

public abstract FloatBuffer duplicate()

返回值：此方法返回新的float缓冲区，该缓冲区带有先前的float缓冲区内容

下面是说明duplicate()方法的示例：

范例1：使用直接floatbuffer

// Java program to demonstrate

// duplicate() method

// Using direct floatbuffer

import java.nio.*;

import java.util.*;

public class GFG {

public static void main(String[] args)

{

// Declaring the capacity of the FloatBuffer

int capacity = 10;

// Creating the FloatBuffer

try {

// creating object of floatbuffer

// and allocating size capacity

FloatBuffer fb1 = FloatBuffer.allocate(capacity);

// putting the value in floatbuffer

fb1.put(8.56F);

fb1.put(2, 9.61F);

fb1.rewind();

// print the Original FloatBuffer

System.out.println("Original FloatBuffer:  "

+ Arrays.toString(fb1.array()));

// Creating a duplicate copy of FloatBuffer

// using duplicate() method

FloatBuffer fb2 = fb1.duplicate();

// print the duplicate copy of FloatBuffer

System.out.print("\nDuplicate FloatBuffer: "

+ Arrays.toString(fb2.array()));

}

catch (IllegalArgumentException e) {

System.out.println("IllegalArgumentException catched");

}

catch (ReadOnlyBufferException e) {

System.out.println("ReadOnlyBufferException catched");

}

}

}

输出：

Original FloatBuffer: [8.56, 0.0, 9.61, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]

Duplicate FloatBuffer: [8.56, 0.0, 9.61, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]

范例2：使用read-onlyfloatbuffer

// Java program to demonstrate

// duplicate() method

// using read-onlyfloatbuffer

import java.nio.*;

import java.util.*;

public class GFG {

public static void main(String[] args)

{

// Declaring the capacity of the FloatBuffer

int capacity = 10;

// Creating the FloatBuffer

try {

// creating object of floatbuffer

// and allocating size capacity

FloatBuffer fb1 = FloatBuffer.allocate(capacity);

// putting the value in floatbuffer

fb1.put(8.56F);

fb1.put(2, 9.61F);

fb1.rewind();

// print the Original FloatBuffer

System.out.println("Original FloatBuffer:  "

+ Arrays.toString(fb1.array()));

// Creating a read-only copy of FloatBuffer

// using asReadOnlyBuffer() method

FloatBuffer readonly = fb1.asReadOnlyBuffer();

// print the read-only copy of FloatBuffer

System.out.print("\nread-only FloatBuffer:  ");

while (readonly.hasRemaining())

System.out.print(readonly.get() + ", ");

System.out.println("");

// Rewinding the readonly FloatBuffer

readonly.rewind();

// Creating a duplicate copy of FloatBuffer

// using duplicate() method

FloatBuffer fb2 = readonly.duplicate();

// print the duplicate copy of FloatBuffer

System.out.print("\nduplicate copy of read-only FloatBuffer:  ");

while (fb2.hasRemaining())

System.out.print(fb2.get() + ", ");

System.out.println("");

}

catch (IllegalArgumentException e) {

System.out.println("IllegalArgumentException catched");

}

catch (ReadOnlyBufferException e) {

System.out.println("ReadOnlyBufferException catched");

}

}

}

输出：

Original FloatBuffer: [8.56, 0.0, 9.61, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]

read-only FloatBuffer: 8.56, 0.0, 9.61, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,

duplicate copy of read-only FloatBuffer: 8.56, 0.0, 9.61, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0,