Java CharBuffer position()方法及实例
java.nio.CharBuffer类 的 position(int newPosition) 方法是用来设置这个缓冲区的位置。如果标记被定义并且大于新的位置,那么它将被丢弃。
语法
public CharBuffer position(int newPosition)
参数。该方法以newPosition为参数,是新的位置值。它必须是非负值,并且不大于当前的限制。
返回值: 该方法返回这个缓冲区。
下面是说明 position() 方法的例子。
例子 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
例子 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]
参考资料: https://docs.oracle.com/javase/9/docs/api/java/nio/CharBuffer.html#position-int-