java.nio.LongBuffer类的arrayOffset()方法用于返回缓冲区第一个元素的缓冲区支持数组内的偏移量。这意味着,如果此缓冲区由数组支持,则缓冲区位置p对应于数组索引p + arrayOffset()。
为了检查此缓冲区是否具有后备数组,可以使用hasArray()方法。它确保此缓冲区具有可访问的后备数组。
用法:
public final Long arrayOffset()
返回值:此方法返回此缓冲区数组中第一个元素的偏移量。
异常:如果此缓冲区由数组支持,但此方法是只读的,则此方法将引发ReadOnlyBufferException
以下示例程序旨在说明arrayOffset()方法。
示例1:
// Java program to demonstrate
// arrayOffset() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the LongBuffer
int capacity = 10;
// Creating the LongBuffer
try {
// creating object of Longbuffer
// and allocating size capacity
LongBuffer ib = LongBuffer.allocate(capacity);
// putting the value in Longbuffer
ib.put(8);
ib.put(2, 9);
// prLong the LongBuffer
System.out.println("LongBuffer: "
+ Arrays.toString(ib.array()));
// prLong the arrayOffset
System.out.println("arrayOffset: "
+ ib.arrayOffset());
}
catch (IllegalArgumentException e) {
System.out.println("IllegalArgumentException catched");
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception throws" + e);
}
}
}
输出:
LongBuffer: [8, 0, 9, 0, 0, 0, 0, 0, 0, 0] arrayOffset: 0
示例2:演示ReadOnlyBufferException。
// Java program to demonstrate
// arrayOffset() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the LongBuffer
int capacity = 10;
// Creating the LongBuffer
try {
// creating object of Longbuffer
// and allocating size capacity
LongBuffer ib = LongBuffer.allocate(capacity);
// putting the value in Longbuffer
ib.put(8);
ib.put(2, 9);
ib.rewind();
// Creating a read-only copy of LongBuffer
// using asReadOnlyBuffer() method
LongBuffer ib1 = ib.asReadOnlyBuffer();
// prLong the LongBuffer
System.out.print("Read only buffer : ");
while (ib1.hasRemaining())
System.out.print(ib1.get() + ", ");
// next line
System.out.println("");
// prLong the arrayOffset
System.out.println("\nTry to prLong the array offset"
+ " of read only buffer");
System.out.println("arrayOffset: " + ib1.arrayOffset());
}
catch (IllegalArgumentException e) {
System.out.println("Exception throws: " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception throws: " + e);
}
}
}
输出:
Read only buffer : 8, 0, 9, 0, 0, 0, 0, 0, 0, 0, Try to prLong the array offset of read only buffer Exception throws: java.nio.ReadOnlyBufferException
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注:本文由纯净天空筛选整理自pawan_asipu大神的英文原创作品 LongBuffer arrayOffset() method in Java。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。