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Java ByteBuffer get()用法及代碼示例


get()

java.nio.ByteBuffer類的get()方法用於讀取緩衝區當前位置的字節，然後遞增該位置。


用法:

public abstract byte get()

返回值：此方法返回緩衝區當前位置的字節。

拋出：此方法拋出BufferUnderflowException-如果緩衝區的當前位置不小於其限製，則拋出此異常。

下麵是說明get()方法的示例：

範例1：

// Java program to demonstrate 
// get() 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 bb = ByteBuffer.allocate(capacity); 
  
            // putting the int to byte value in ByteBuffer 
            bb.put((byte)20); 
            bb.put((byte)30); 
            bb.put((byte)40); 
            bb.rewind(); 
  
            // print the ByteBuffer 
            System.out.println("Original ByteBuffer:  "
                               + Arrays.toString(bb.array())); 
  
            // Reads the byte at this buffer's current position 
            // using get() method 
            byte value = bb.get(); 
  
            // print the byte value 
            System.out.println("\nByte Value: " + value); 
  
            // Reads the  Byte at this buffer's next position 
            // using get() method 
            byte value1 = bb.get(); 
  
            // print the Float value 
            System.out.print("\nNext Byte Value: " + value1); 
        } 
  
        catch (IllegalArgumentException e) { 
  
            System.out.println("\nException Thrown : " + e); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("\nException Thrown : " + e); 
        } 
  
        catch (BufferUnderflowException e) { 
  
            System.out.println("\nException Thrown : " + e); 
        } 
    } 
}
輸出： 
Original ByteBuffer:  [20, 30, 40, 0, 0]

Byte Value: 20

Next Byte Value: 30

範例2：

// Java program to demonstrate 
// get() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the ByteBuffer 
        int capacity = 3; 
  
        // Creating the ByteBuffer 
        try { 
  
            // creating object of ByteBuffer 
            // and allocating size capacity 
            ByteBuffer bb = ByteBuffer.allocate(capacity); 
  
            // putting the int to byte typecast value in ByteBuffer 
            bb.put((byte)20); 
            bb.put((byte)30); 
  
            // print the ByteBuffer 
            System.out.println("Original ByteBuffer:  "
                               + Arrays.toString(bb.array())); 
  
            // Reads the byte at this buffer's current position 
            // using get() method 
            byte value = bb.get(); 
  
            // print the byte value 
            System.out.println("\nByte Value: " + value); 
  
            // Reads the Byte at this buffer's next position 
            // using get() method 
            System.out.print("\nsince the buffer current position is incremented"); 
            System.out.print(" to greater than its limit "); 
  
            byte value1 = bb.get(); 
  
            // print the Byte value 
            System.out.print("\nNext Byte Value: " + value1); 
        } 
  
        catch (IllegalArgumentException e) { 
  
            System.out.println("\nIllegalArgumentException catched"); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("\nReadOnlyBufferException catched"); 
        } 
  
        catch (BufferUnderflowException e) { 
  
            System.out.println("\nException throws : " + e); 
        } 
    } 
}
輸出： 
Original ByteBuffer:  [20, 30, 0]

Byte Value: 0

since the buffer current position is incremented to greater than its limit 
Exception throws : java.nio.BufferUnderflowException

get(int索引)


ByteBuffer的get(int index)方法用於讀取指定索引處的文章。

用法:

public abstract byte get(int index)

參數：此方法將索引(將從中讀取Byte的索引)作為參數。

返回值：此方法返回給定索引處的Byte值。

異常：此方法引發IndexOutOfBoundsException。如果index為負或不小於緩衝區的限製，則拋出此異常。

以下示例說明了get(int index)方法：

範例1：

// Java program to demonstrate 
// get(int index) method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the ByteBuffer 
        int capacity = 3; 
  
        // Creating the ByteBuffer 
        try { 
  
            // creating object of ByteBuffer 
            // and allocating size capacity 
            ByteBuffer bb = ByteBuffer.allocate(capacity); 
  
            // putting the int to byte typecast value in ByteBuffer 
            bb.put((byte)20); 
            bb.put((byte)30); 
            bb.put((byte)40); 
  
            // print the ByteBuffer 
            System.out.println("Original ByteBuffer:  "
                               + Arrays.toString(bb.array())); 
  
            // Reads the Byte at the index 0 of the Bytebuffer 
            // using get() method 
            byte value0 = bb.get(0); 
  
            // print the Byte value 
            System.out.println("\nByte Value at index 0: " + value0); 
  
            // Reads the Byte at the index 1 of the Bytebuffer 
            // using get() method 
            byte value1 = bb.get(1); 
  
            // print the Byte value 
            System.out.println("\nByte Value at index 1: " + value1); 
  
            // Reads the Byte at the index 2 of the Bytebuffer 
            // using get() method 
            byte value2 = bb.get(2); 
  
            // print the Byte value 
            System.out.println("\nByte Value at index 2: " + value2); 
        } 
  
        catch (IllegalArgumentException e) { 
  
            System.out.println("\nIllegalArgumentException catched"); 
        } 
  
        catch (IndexOutOfBoundsException e) { 
  
            System.out.println("\nReadOnlyBufferException catched"); 
        } 
  
        catch (BufferUnderflowException e) { 
  
            System.out.println("\nException throws : " + e); 
        } 
    } 
}
輸出： 
Original ByteBuffer:  [20, 30, 40]

Byte Value at index 0: 20

Byte Value at index 1: 30

Byte Value at index 2: 40

範例2：

// Java program to demonstrate 
// get(int index) method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the ByteBuffer 
        int capacity = 3; 
  
        // Creating the ByteBuffer 
        try { 
  
            // creating object of ByteBuffer 
            // and allocating size capacity 
            ByteBuffer bb = ByteBuffer.allocate(capacity); 
  
            // putting the int to byte typecast value in ByteBuffer 
            bb.put((byte)20); 
            bb.put((byte)30); 
            bb.put((byte)40); 
  
            // print the ByteBuffer 
            System.out.println("Original ByteBuffer:  "
                               + Arrays.toString(bb.array())); 
  
            // Reads the Byte at the index 0 of the Bytebuffer 
            // using get() method 
            byte value0 = bb.get(0); 
  
            // print the Byte value 
            System.out.println("\nByte Value at index 0: " + value0); 
  
            // Reads the Byte at the index 1 of the Bytebuffer 
            // using get() method 
            byte value1 = bb.get(1); 
  
            // print the Byte value 
            System.out.println("\nByte Value at index 1: " + value1); 
  
            // Reads the Byte at the index 4 of the Bytebuffer 
            // using get() method 
            System.out.println("\nTrying to get the byte"
                               + " of index greater than its limit "); 
            byte value2 = bb.get(4); 
  
            // print the Byte value 
            System.out.println("\nByte Value at index 4: " + value2); 
        } 
  
        catch (IndexOutOfBoundsException e) { 
  
            System.out.println("\nException throws : " + e); 
        } 
  
        catch (BufferUnderflowException e) { 
  
            System.out.println("\nException throws : " + e); 
        } 
    } 
}
輸出： 
Original ByteBuffer:  [20, 30, 40]

Byte Value at index 0: 20

Byte Value at index 1: 30

Trying to get the byte of index greater than its limit 

Exception throws : java.lang.IndexOutOfBoundsException


相關用法


注：本文由純淨天空篩選整理自RohitPrasad3大神的英文原創作品 ByteBuffer get() 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。