Java中的 CharBuffer position() 方法及示例
Java.nio.CharBuffer 类的position(int newPosition)方法用于设置这个缓冲区的位置。如果标记已定义且大于新位置,则将其丢弃。
句法:
public CharBuffer position(int newPosition)
参数:该方法以newPosition为参数,即新的位置值。它必须是非负的并且不大于当前限制。
返回值:此方法返回此缓冲区。
以下是说明position()方法的示例:
示例 1:
// Java program to demonstrate
// position() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
char[] carr = { 'a', 'b', 'c', 'd' };
// creating object of CharBuffer
// and allocating size capacity
CharBuffer cb = CharBuffer.wrap(carr);
// try to set the position at index 2
// using position() method
cb.position(2);
// Set this buffer mark position
cb.mark();
// try to set the position at index 4
// using position() method
cb.position(4);
// display position
System.out.println("position before reset: "
+ cb.position());
// try to call reset() to restore
// to the position we marked
cb.reset();
// display position
System.out.println("position after reset: "
+ cb.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 CharBuffer
// and allocating size capacity
CharBuffer cb = CharBuffer.allocate(4);
// try to set the position at index 1
// using position() method
cb.position(1);
// putting the value of CharBuffer
// using append() method
cb.append('x');
// try to set the position at index 3
// using position() method
cb.position(3);
// putting the value of CharBuffer
// using append() method
cb.append("y");
// display position
System.out.println("CharBuffer: "
+ Arrays.toString(cb.array()));
}
}
输出:
CharBuffer: [, x,, y]
参考: https://docs.oracle.com/javase/9/docs/api/ Java/nio/CharBuffer.html#position-int-