Java 中的 CharBuffer compact()方法
原文:https://www . geesforgeks . org/char buffer-compact-method-in-Java/
java.nio.CharBuffer 类的 compact() 方法用于压缩给定的缓冲区。
缓冲区的当前位置与其限制之间的值被复制到缓冲区的开头。然后，缓冲器的位置被设置为 n+1，其极限被设置为其容量。缓冲区的位置被设置为复制的浮点数。
语法:
public abstract CharBuffer compact()
返回值:该方法返回与该缓冲区内容相同的新 CharBuffer 。
异常:如果这个缓冲区是只读的，这个方法抛出readonlybufferrexception。
下面的程序说明了紧凑()的方法:
例 1:
// Java program to demonstrate
// compact() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the CharBuffer
int capacity = 10;
// Creating the CharBuffer
// creating object of Intbuffer
// and allocating size capacity
CharBuffer ic = CharBuffer.allocate(capacity);
// putting the value in Intbuffer
ic.put('a');
ic.put('b');
ic.put('c');
// print the CharBuffer
System.out.println("Original CharBuffer: "
+ Arrays.toString(ic.array()));
System.out.println("Position: " + ic.position());
System.out.println("limit: " + ic.limit());
// Creating a compacted CharBuffer of same CharBuffer
// using compact() method
CharBuffer CharBuffer = ic.compact();
// print the CharBuffer
System.out.println("\nCompacted CharBuffer: "
+ Arrays.toString(CharBuffer.array()));
System.out.println("Position: " + CharBuffer.position());
System.out.println("limit: " + CharBuffer.limit());
// putting the value in compacted Intbuffer
CharBuffer.put('g');
// print the CharBuffer
System.out.println("\nUpdated Compacted CharBuffer: "
+ Arrays.toString(CharBuffer.array()));
System.out.println("Position: " + CharBuffer.position());
System.out.println("limit: " + CharBuffer.limit());
}
}
Output:
Original CharBuffer: [a, b, c, , , , , , , ]
Position: 3
limit: 10
Compacted CharBuffer: [, , , , , , , , , ]
Position: 7
limit: 10
Updated Compacted CharBuffer: [, , , , , , , g, , ]
Position: 8
limit: 10
例 2:
// Java program to demonstrate
// compact() method
import java.nio.*;
import java.util.*;
public class GFG {
public static void main(String[] args)
{
// Declaring the capacity of the CharBuffer
int capacity = 10;
// Creating the CharBuffer
try {
// creating object of CharBuffer
// and allocating size capacity
CharBuffer cb = CharBuffer.allocate(capacity);
// putting the value in CharBuffer
cb.put('a');
cb.put('b');
cb.put('b');
cb.rewind();
// Creating a read-only copy of CharBuffer
// using asReadOnlyBuffer() method
CharBuffer cb1 = cb.asReadOnlyBuffer();
// print the ReadOnlyBuffer
System.out.print("ReadOnlyBuffer CharBuffer: ");
while (cb1.hasRemaining())
System.out.print(cb1.get() + ", ");
System.out.println("");
// print the Position of CharBuffer cb
System.out.println("\nPosition: " + cb.position());
// print the Limit of CharBuffer cb
System.out.println("\nlimit: " + cb.limit());
// Creating a compacted CharBuffer of same ReadOnlyBuffer
// using compact() method
System.out.println("\nTrying to compact the ReadOnlyBuffer cb1");
CharBuffer CharBuffer = cb1.compact();
}
catch (IllegalArgumentException e) {
System.out.println("Exception throws " + e);
}
catch (ReadOnlyBufferException e) {
System.out.println("Exception throws " + e);
}
}
}
Output:
ReadOnlyBuffer CharBuffer: a, b, b, , , , , , , ,
Position: 0
limit: 10
Trying to compact the ReadOnlyBuffer cb1
Exception throws java.nio.ReadOnlyBufferException
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