java.nio.CharBuffer類的clear()方法用於清除此緩衝區。位置設置為零,限製設置為容量,並且標記被丟棄。在使用序列channel-read之前,請調用此方法,或者進行操作以填充此緩衝區。
例如:
// Prepare buffer for reading buf.clear(); // Read data in.read(buf);
該方法實際上並沒有擦除緩衝區中的數據,但它的命名方式就好像它確實如此,因為該方法最常用於可能是這種情況的情況。
用法:
public final CharBuffer clear()
返回值:此方法返回此緩衝區。
下麵是說明clear()方法的示例:
範例1:
// Java program to demonstrate
// clear() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
try {
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
cb.position(2);
// Set this buffer mark position
// using mark() method
cb.mark();
// try to set the position at index 4
cb.position(4);
// display position
System.out.println("position before reset:"
+ cb.position());
// try to call clear() to restore
// to the position at index 0
// by discarding the mark
cb.clear();
// display position
System.out.println("position after reset:"
+ cb.position());
}
catch (InvalidMarkException e) {
System.out.println("new position is less than "
+ "the position we "
+ "marked before ");
System.out.println("Exception throws:" + e);
}
}
}
輸出:
position before reset:4 position after reset:0
範例2:
// Java program to demonstrate
// clear() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
char[] carr = { '.', '<', '@', 'a' };
// creating object of CharBuffer
// and allocating size capacity
CharBuffer cb = CharBuffer.wrap(carr);
// try to set the position at index 2
cb.position(3);
// display position
System.out.println("position before clear:"
+ cb.position());
// try to call clear() to restore
// to the position at index 0
// by discarding the mark
cb.clear();
// display position
System.out.println("position after clear:"
+ cb.position());
}
}
輸出:
position before clear:3 position after clear:0
參考: https://docs.oracle.com/javase/9/docs/api/java/nio/CharBuffer.html#clear-
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注:本文由純淨天空篩選整理自RohitPrasad3大神的英文原創作品 CharBuffer clear() methods in Java with Examples。非經特殊聲明,原始代碼版權歸原作者所有,本譯文未經允許或授權,請勿轉載或複製。