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Java - ByteBuffer getChar()用法及代码示例

getChar()

java.nio.ByteBuffer类的getChar()方法用于获取读取char值的方法

读取此缓冲区当前位置的下两个字节,根据当前字节顺序将它们组成一个char值,然后将该位置加2。

用法:


public abstract char getChar()

返回值:此方法返回缓冲区当前位置的char值

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getChar()方法的示例:

范例1:

// Java program to demonstrate 
// getChar() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the ByteBuffer 
        int capacity = 50; 
  
        // Creating the ByteBuffer 
        try { 
  
            // creating object of ByteBuffer 
            // and allocating size capacity 
            ByteBuffer bb = ByteBuffer.allocate(capacity); 
  
            // putting the string in the bytebuffer 
            bb.asCharBuffer().put("Geeks"); 
  
            // rewind the Bytebuffer 
            bb.rewind(); 
  
            // Declaring the variable 
            char c; 
  
            // print the ByteBuffer 
            System.out.println("Original ByteBuffer: "); 
            while ((c = bb.getChar()) != 0) 
                System.out.print(c + " "); 
  
            // rewind the Bytebuffer 
            bb.rewind(); 
  
            // Reads the char at this buffer's current position 
            // using getChar() method 
            char value = bb.getChar(); 
  
            // print the char value 
            System.out.println("\n\nByte Value: " + value); 
  
            // Reads the  char at this buffer's next position 
            // using getChar() method 
            char value1 = bb.getChar(); 
  
            // print the char 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: 
G e e k s 

Byte Value: G

Next Byte Value: e

范例2:

// Java program to demonstrate 
// getChar() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the ByteBuffer 
        int capacity = 8; 
  
        // Creating the ByteBuffer 
        try { 
  
            // creating object of ByteBuffer 
            // and allocating size capacity 
            ByteBuffer bb = ByteBuffer.allocate(capacity); 
  
            // putting the string in the bytebuffer 
            bb.asCharBuffer().put("abc"); 
  
            // rewind the Bytebuffer 
            bb.rewind(); 
  
            // Declaring the variable 
            char c; 
  
            // print the ByteBuffer 
            System.out.print("Original ByteBuffer: "); 
            while ((c = bb.getChar()) != 0) 
                System.out.print(c + " "); 
  
            // rewind the Bytebuffer 
            bb.rewind(); 
  
            // Reads the char at this buffer's current position 
            // using getChar() method 
            char value = bb.getChar(); 
  
            // print the char value 
            System.out.println("\n\nFirst char Value: " + value); 
  
            // Reads the  char at this buffer's next position 
            // using getChar() method 
            char value1 = bb.getChar(); 
  
            // print the char value 
            System.out.println("\nSecond char Value: " + value1); 
  
            // Reads the  char at this buffer's next position 
            // using getChar() method 
            char value2 = bb.getChar(); 
  
            // print the char value 
            System.out.println("\nThird char Value: " + value2); 
  
            // Reads the  char at this buffer's next position 
            // using getChar() method 
            System.out.print("\nsince the buffer current position is incremented"); 
            System.out.print(" to greater than its limit "); 
            char value3 = bb.getChar(); 
            char value4 = bb.getChar(); 
        } 
  
        catch (BufferOverflowException 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: a b c 

First char Value: a

Second char Value: b

Third char Value: c

since the buffer current position is incremented to greater than its limit 
Exception Thrown: java.nio.BufferUnderflowException
get(int索引)

ByteBuffer的get(int index)方法用于读取给定索引处的两个字节,并根据当前字节顺序将它们组成一个char值。

用法:

public abstract char getChar(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char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 
// getChar() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the ByteBuffer 
        int capacity = 50; 
  
        // Creating the ByteBuffer 
        try { 
  
            // creating object of ByteBuffer 
            // and allocating size capacity 
            ByteBuffer bb = ByteBuffer.allocate(capacity); 
  
            // putting the string in the bytebuffer 
            bb.asCharBuffer().put("abc"); 
  
            // rewind the Bytebuffer 
            bb.rewind(); 
  
            // Declaring the variable 
            char c; 
  
            // print the ByteBuffer 
            System.out.print("Original ByteBuffer: "); 
            while ((c = bb.getChar()) != 0) 
                System.out.print(c + " "); 
  
            // rewind the Bytebuffer 
            bb.rewind(); 
  
            // Reads the char at this buffer's at index 0 
            // using getChar() method 
            char value0 = bb.getChar(0); 
  
            // print the char value 
            System.out.println("\n\nchar Value at index 0: "
                               + value0); 
  
            // Reads the  char at this buffer's at index 2 
            // using getChar() method 
            char value1 = bb.getChar(2); 
  
            // print the char value 
            System.out.println("\nchar Value at index 2: "
                               + value1); 
  
            // Reads the  char at this buffer's at index 4 
            // using getChar() method 
            char value2 = bb.getChar(4); 
  
            // print the char value 
            System.out.println("\nchar Value at index 4: "
                               + value2); 
        } 
  
        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: a b c 

char Value at index 0: a

char Value at index 2: b

char Value at index 4: c

范例2:

// Java program to demonstrate 
// getChar() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the ByteBuffer 
        int capacity = 50; 
  
        // Creating the ByteBuffer 
        try { 
  
            // creating object of ByteBuffer 
            // and allocating size capacity 
            ByteBuffer bb = ByteBuffer.allocate(capacity); 
  
            // putting the string in the bytebuffer 
            bb.asCharBuffer().put("abc"); 
  
            // rewind the Bytebuffer 
            bb.rewind(); 
  
            // Declaring the variable 
            char c; 
  
            // print the ByteBuffer 
            System.out.print("Original ByteBuffer: "); 
            while ((c = bb.getChar()) != 0) 
                System.out.print(c + " "); 
  
            // rewind the Bytebuffer 
            bb.rewind(); 
  
            // Reads the char at this buffer's at index 0 
            // using getChar() method 
            char value0 = bb.getChar(0); 
  
            // print the char value 
            System.out.println("\n\nchar Value at index 0: "
                               + value0); 
  
            // Reads the  char at this buffer's at index 2 
            // using getChar() method 
            char value1 = bb.getChar(2); 
  
            // print the char value 
            System.out.println("\nchar Value at index 2: "
                               + value1); 
  
            // Reads the  char at this buffer's at index 4 
            // using getChar() method 
            System.out.println("\nTrying to get the char"
                               + " at negative index "); 
            char value2 = bb.getChar(-4); 
        } 
  
        catch (IndexOutOfBoundsException 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: a b c 

char Value at index 0: a

char Value at index 2: b

Trying to get the char at a negative index 

Exception Thrown: java.lang.IndexOutOfBoundsException

参考:



相关用法

注:本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 ByteBuffer getChar() 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。