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Java - ByteBuffer get()用法及代码示例

get()

java.nio.ByteBuffer类的get()方法用于读取缓冲区当前位置的字节,然后递增该位置。


用法:

public abstract byte get()

返回值:此方法返回缓冲区当前位置的字节。

抛出:此方法抛出BufferUnderflowException-如果缓冲区的当前位置不小于其限制,则抛出此异常。

下面是说明get()方法的示例:

范例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); 
        } 
    } 
}
输出:
Original ByteBuffer:  [20, 30, 40, 0, 0]

Byte Value: 20

Next Byte Value: 30

范例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); 
        } 
    } 
}
输出:
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)方法用于读取指定索引处的文章。

用法:

public abstract byte get(int index)

参数:此方法将索引(将从中读取Byte的索引)作为参数。

返回值:此方法返回给定索引处的Byte值。

异常:此方法引发IndexOutOfBoundsException。如果index为负或不小于缓冲区的限制,则抛出此异常。

以下示例说明了get(int index)方法:

范例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); 
        } 
    } 
}
输出:
Original ByteBuffer:  [20, 30, 40]

Byte Value at index 0: 20

Byte Value at index 1: 30

Byte Value at index 2: 40

范例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); 
        } 
    } 
}
输出:
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


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注:本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 ByteBuffer get() method in Java with Examples。非经特殊声明,原始代码版权归原作者所有,本译文的传播和使用请遵循“署名-相同方式共享 4.0 国际 (CC BY-SA 4.0)”协议。