Java中的 ByteBuffer asLongBuffer() 方法及示例
Java.nio.ByteBuffer类的asLongBuffer()方法用于将此字节缓冲区的视图创建为长缓冲区。
新缓冲区的内容将从该缓冲区的当前位置开始。此缓冲区内容的更改将在新缓冲区中可见,反之亦然;两个缓冲区的位置、限制和标记值将是独立的。
新缓冲区的位置为零,其容量和限制将是该缓冲区中剩余的字节数除以八,其标记将是未定义的。当且仅当此缓冲区是直接的时,新缓冲区将是直接的,并且当且仅当此缓冲区是只读的时,它将是只读的。
句法:
public abstract LongBuffer asLongBuffer()
返回值:此方法返回一个新的长缓冲区。
下面是说明asLongBuffer()方法的示例:
示例 1:
Java
// Java program to demonstrate
// asLongBuffer() method
// for ByteBuffer
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 50;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// changing bytebuffer into
// LongBuffer
LongBuffer lb = bb.asLongBuffer();
// putting the value in LongBuffer
lb.put(1000000);
lb.put(2000000);
lb.put(3000000);
lb.put(3000000);
lb.rewind();
// Declaring variable c
long c;
// print the ByteBuffer
System.out.print("LongBuffer : ");
while ((c = lb.get()) != 0)
System.out.print(c + " ");
}
catch (IllegalArgumentException e) {
System.out.println("Exception thrown : " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception thrown : " + e);
}
}
}
Java
// Java program to demonstrate
// asLongBuffer() method
// for ByteBuffer
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 50;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// changing bytebuffer into
// LongBuffer
LongBuffer lb = bb.asLongBuffer();
// putting the value in LongBuffer
lb.put(1000000);
lb.put(2000000);
lb.put(3000000);
lb.rewind();
// Declaring variable c
long c;
// print the ByteBuffer
System.out.print("LongBuffer : ");
while ((c = lb.get()) != 0)
System.out.print(c + " ");
// Creating a read-only copy of ByteBuffer
// using asReadOnlyBuffer() method
ByteBuffer bb1 = bb.asReadOnlyBuffer();
// changing read-only bytebuffer into
// read-only LongBuffer
LongBuffer lb1 = bb1.asLongBuffer();
// putting the value in read-only LongBuffer
System.out.println("\n\nTrying to put the value "
+ "in read only LongBuffer");
lb1.put(10);
lb1.put(20);
lb1.put(30);
lb1.rewind();
}
catch (IllegalArgumentException e) {
System.out.println("Exception thrown : " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception thrown : " + e);
}
}
}
输出:
LongBuffer : 1000000 2000000 3000000 3000000
示例 2:
Java
// Java program to demonstrate
// asLongBuffer() method
// for ByteBuffer
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the ByteBuffer
int capacity = 50;
// Creating the ByteBuffer
try {
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(capacity);
// changing bytebuffer into
// LongBuffer
LongBuffer lb = bb.asLongBuffer();
// putting the value in LongBuffer
lb.put(1000000);
lb.put(2000000);
lb.put(3000000);
lb.rewind();
// Declaring variable c
long c;
// print the ByteBuffer
System.out.print("LongBuffer : ");
while ((c = lb.get()) != 0)
System.out.print(c + " ");
// Creating a read-only copy of ByteBuffer
// using asReadOnlyBuffer() method
ByteBuffer bb1 = bb.asReadOnlyBuffer();
// changing read-only bytebuffer into
// read-only LongBuffer
LongBuffer lb1 = bb1.asLongBuffer();
// putting the value in read-only LongBuffer
System.out.println("\n\nTrying to put the value "
+ "in read only LongBuffer");
lb1.put(10);
lb1.put(20);
lb1.put(30);
lb1.rewind();
}
catch (IllegalArgumentException e) {
System.out.println("Exception thrown : " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception thrown : " + e);
}
}
}
输出:
LongBuffer : 1000000 2000000 3000000
Trying to put the value in read only LongBuffer
Exception thrown : java.nio.ReadOnlyBufferException