Java 中的字节缓冲位置()方法，示例
原文:https://www . geeksforgeeks . org/bytebuffer-position-methods-in-Java-with-examples/
java.nio.ByteBuffer 类 的位置(int newPosition) 方法用于设置该缓冲区的位置。如果标记被定义并且比新位置大，则它被丢弃。
语法:
public ByteBuffer position(int newPosition)
参数:该方法以新位置为参数，为新位置值。它必须是非负的，并且不大于电流限制。
返回值:这个方法返回这个缓冲区。
以下是说明位置()方法的例子:
示例 1:
// Java program to demonstrate
// position() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
byte[] barr = { 10, 20, 30, 40 };
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.wrap(barr);
// try to set the position at index 2
// using position() method
bb.position(2);
// Set this buffer mark position
bb.mark();
// try to set the position at index 4
// using position() method
bb.position(4);
// display position
System.out.println("position before reset: "
+ bb.position());
// try to call reset() to restore
// to the position we marked
bb.reset();
// display position
System.out.println("position after reset: "
+ bb.position());
}
}
输出:
position before reset: 4
position after reset: 2
示例 2:
// Java program to demonstrate
// position() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// creating object of ByteBuffer
// and allocating size capacity
ByteBuffer bb = ByteBuffer.allocate(4);
// try to set the position at index 1
// using position() method
bb.position(1);
// putting the value of ByteBuffer
// using put() method
bb.put((byte)10);
// try to set the position at index 3
// using position() method
bb.position(3);
// putting the value of ByteBuffer
// using put() method
bb.put((byte)30);
// display position
System.out.println("ByteBuffer: "
+ Arrays.toString(bb.array()));
}
}
输出:
ByteBuffer: [0, 10, 0, 30]
参考:https://docs . Oracle . com/javase/9/docs/API/Java/nio/bytebuffer . html # position-int-
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