Java ByteBuffer slice()用法及代碼示例

java.nio.ByteBuffer類的slice()方法用於創建一個新的字節緩衝區，其內容是給定緩衝區內容的共享子序列。

新緩衝區的內容將從該緩衝區的當前位置開始。對該緩衝區內容的更改將在新緩衝區中可見，反之亦然。這兩個緩衝區的位置，限製和標記值將是獨立的。

新緩衝區的位置將為零，其容量和限製將為該緩衝區中剩餘的浮點數，並且其標記將不確定。當且僅當該緩衝區是直接緩衝區時，新緩衝區才是直接緩衝區；當且僅當該緩衝區是隻讀緩衝區時，新緩衝區才是隻讀緩衝區。

用法:

public abstract ByteBuffer slice()

返回值：此方法返回新的字節緩衝區。

下麵是說明slice()方法的示例：

範例1：

// Java program to demonstrate 
// slice() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the ByteBuffer 
        int capacity = 5; 
  
        // Creating the ByteBuffer 
        try { 
  
            // creating object of ByteBuffer 
            // and allocating size capacity 
            ByteBuffer bb1 
                = ByteBuffer.allocate(capacity); 
  
            // putting the value in ByteBuffer 
            bb1.put((byte)10); 
            bb1.put((byte)20); 
  
            // print the ByteBuffer 
            System.out.println("Original ByteBuffer: "
                               + Arrays.toString(bb1.array())); 
  
            // print the ByteBuffer position 
            System.out.println("\nposition:  "
                               + bb1.position()); 
  
            // print the ByteBuffer capacity 
            System.out.println("\ncapacity:  "
                               + bb1.capacity()); 
  
            // Creating a shared subsequence buffer 
            // of given ByteBuffer 
            // using slice() method 
            ByteBuffer bb2 = bb1.slice(); 
  
            // print the shared subsequance buffer 
            System.out.println("\nshared subsequance ByteBuffer: "
                               + Arrays.toString(bb2.array())); 
  
            // print the ByteBuffer position 
            System.out.println("\nposition:  " + bb2.position()); 
  
            // print the ByteBuffer capacity 
            System.out.println("\ncapacity:  " + bb2.capacity()); 
        } 
  
        catch (IllegalArgumentException e) { 
  
            System.out.println("IllegalArgumentException catched"); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("ReadOnlyBufferException catched"); 
        } 
    } 
}

輸出：

Original ByteBuffer: [10, 20, 0, 0, 0]

position:  2

capacity:  5

shared subsequance ByteBuffer: [10, 20, 0, 0, 0]

position:  0

capacity:  3

範例2：

// Java program to demonstrate 
// slice() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the ByteBuffer 
        int capacity = 5; 
  
        // Creating the ByteBuffer 
        try { 
  
            // creating object of ByteBuffer 
            // and allocating size capacity 
            ByteBuffer bb1 = ByteBuffer.allocate(capacity); 
  
            // putting the value in ByteBuffer 
            bb1.put((byte)10) 
                .put((byte)20) 
                .put((byte)30) 
                .put((byte)40) 
                .put((byte)50); 
  
            // print the ByteBuffer 
            System.out.println("Original ByteBuffer: "
                               + Arrays.toString(bb1.array())); 
  
            // print the ByteBuffer position 
            System.out.println("\nposition:  "
                               + bb1.position()); 
  
            // print the ByteBuffer capacity 
            System.out.println("\ncapacity:  "
                               + bb1.capacity()); 
  
            // Creating a shared subsequence buffer 
            // of given ByteBuffer 
            // using slice() method 
            ByteBuffer bb2 = bb1.slice(); 
  
            // print the shared subsequance buffer 
            System.out.println("\nshared subsequance ByteBuffer: "
                               + Arrays.toString(bb2.array())); 
  
            // print the ByteBuffer position 
            System.out.println("\nposition:  " + bb2.position()); 
  
            // print the ByteBuffer capacity 
            System.out.println("\ncapacity:  " + bb2.capacity()); 
        } 
  
        catch (IllegalArgumentException e) { 
  
            System.out.println("IllegalArgumentException catched"); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("ReadOnlyBufferException catched"); 
        } 
    } 
}

輸出：

Original ByteBuffer: [10, 20, 30, 40, 50]

position:  5

capacity:  5

shared subsequance ByteBuffer: [10, 20, 30, 40, 50]

position:  0

capacity:  0

參考： https://docs.oracle.com/javase/9/docs/api/java/nio/ByteBuffer.html#slice–

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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 ByteBuffer slice() method 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。