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Java CharBuffer append()用法及代码示例


append(char c)

java.nio.CharBuffer类的append(char c)方法用于将指定的char附加到此缓冲区(可选操作)。调用dst.append(c)形式的方法的行为与调用dst.put(c)的行为完全相同

用法:

public CharBuffer append(char c)

参数：此方法需要附加16位char。


返回值：此方法返回此缓冲区，在其中插入char值。

异常：此方法引发以下异常：

  • BufferOverflowException-如果此缓冲区中的空间不足
  • ReadOnlyBufferException-如果此缓冲区是只读的

下面的示例说明了append(char c)方法：

范例1：

// Java program to demonstrate 
// append() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the CharBuffer 
        int capacity = 3; 
  
        // Creating the CharBuffer 
        try { 
  
            // creating object of CharBuffer 
            // and allocating size capacity 
            CharBuffer charbuffer 
                = CharBuffer.allocate(capacity); 
  
            // append the value in CharBuffer 
            // using append() method 
            charbuffer.append('a') 
                .append('b') 
                .append('c') 
                .rewind(); 
  
            // print the CharBuffer 
            System.out.println("Original CharBuffer:  "
                               + Arrays.toString( 
                                     charbuffer.array())); 
        } 
  
        catch (BufferOverflowException e) { 
  
            System.out.println("Exception throws:" + e); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("Exception throws:" + e); 
        } 
    } 
}
输出： 
Original CharBuffer: [a, b, c]

范例2：演示BufferOverflowException。

// Java program to demonstrate 
// append() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the CharBuffer 
        int capacity = 3; 
  
        // Creating the CharBuffer 
        try { 
  
            // creating object of CharBuffer 
            // and allocating size capacity 
            CharBuffer charbuffer 
                = CharBuffer.allocate(capacity); 
  
            // append the value in CharBuffer 
            // using append() method 
            charbuffer.append('a') 
                .append('b') 
                .append('c'); 
  
            // print the CharBuffer 
            System.out.println("Original CharBuffer:  "
                               + Arrays.toString( 
                                     charbuffer.array())); 
  
            // again appending the value in CharBuffer 
            // using append() method 
            System.out.println("\nBuffer position:"
                               + charbuffer.position()); 
            charbuffer.append('x'); 
        } 
  
        catch (BufferOverflowException e) { 
  
            System.out.println("buffer's current position "
                               + "is not smaller than its limit"); 
            System.out.println("Exception throws:" + e); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("Exception throws:" + e); 
        } 
    } 
}
输出： 
Original CharBuffer: [a, b, c]

Buffer position:3
buffer's current position is not smaller than its limit
Exception throws:java.nio.BufferOverflowException

范例3：演示ReadOnlyBufferException。

// Java program to demonstrate 
// append() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the CharBuffer 
        int capacity = 3; 
  
        // Creating the CharBuffer 
        try { 
  
            // creating object of CharBuffer 
            // and allocating size capacity 
            CharBuffer charbuffer 
                = CharBuffer.allocate(capacity); 
  
            // append the value in CharBuffer 
            // using append() method 
            charbuffer.append('a') 
                .append('b') 
                .append('c'); 
  
            // print the CharBuffer 
            System.out.println("Original CharBuffer:  "
                               + Arrays.toString( 
                                     charbuffer.array())); 
  
            // Creating a read-only copy of CharBufferBuffer 
            // using asReadOnlyBuffer() method 
            CharBuffer chb = charbuffer.asReadOnlyBuffer(); 
  
            System.out.println("\nTrying to append the char value"
                               + " in read-only buffer"); 
  
            // putting the value in readonly CharBuffer 
            // using append() method 
            chb.append('d'); 
        } 
  
        catch (BufferOverflowException e) { 
  
            System.out.println("buffer's current position "
                               + "is not smaller than its limit"); 
            System.out.println("Exception throws:" + e); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("Exception throws:" + e); 
        } 
    } 
}
输出： 
Original CharBuffer: [a, b, c]

Trying to append the char value in read-only buffer
Exception throws:java.nio.ReadOnlyBufferException

参考： https://docs.oracle.com/javase/9/docs/api/java/nio/CharBuffer.html#append-char-


append(CharSequence csq)

java.nio.CharBuffer类的append(CharSequence csq)方法用于将指定的字符序列追加到此缓冲区(可选操作)。

根据字符序列csq的toString规范，可能不会附加整个序列。例如，调用字符缓冲区的toString方法将返回一个子序列，其内容取决于缓冲区的位置和限制。

用法:

public CharBuffer append(CharSequence csq)

参数：此方法将字符序列追加。如果csq为null，则将四个字符“null”附加到此字符缓冲区。

返回值：此方法返回此缓冲区。

异常：此方法引发以下异常：

  • BufferOverflowException-如果此缓冲区中的空间不足
  • ReadOnlyBufferException-如果此缓冲区是只读的

以下示例说明了append(CharSequence csq)方法：

范例1：

// Java program to demonstrate 
// append() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the CharBuffer 
        int capacity = 3; 
  
        // Declaring and intializing CharSequence 
        CharSequence cha = "cow"; 
  
        // Creating the CharBuffer 
        try { 
  
            // creating object of CharBuffer 
            // and allocating size capacity 
            CharBuffer charbuffer 
                = CharBuffer.allocate(capacity); 
  
            // appending the CharSequence in CharBuffer 
            // using append() method 
            charbuffer.append(cha) 
                .rewind(); 
  
            // print the CharBuffer 
            System.out.println("Original CharBuffer:  "
                               + Arrays.toString( 
                                     charbuffer.array())); 
        } 
  
        catch (BufferOverflowException e) { 
  
            System.out.println("Exception throws:" + e); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("Exception throws:" + e); 
        } 
    } 
}
输出： 
Original CharBuffer:

范例2：演示BufferOverflowException。

// Java program to demonstrate 
// append() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the CharBuffer 
        int capacity = 2; 
  
        // Declaring and intializing CharSequence 
        CharSequence cha = "cow"; 
  
        // Creating the CharBuffer 
        try { 
  
            // creating object of CharBuffer 
            // and allocating size capacity 
            CharBuffer charbuffer 
                = CharBuffer.allocate(capacity); 
  
            // appending the CharSequence in CharBuffer 
            // using append() method 
            charbuffer.append(cha) 
                .rewind(); 
  
            // print the CharBuffer 
            System.out.println("Original CharBuffer:  "
                               + Arrays.toString( 
                                     charbuffer.array())); 
        } 
  
        catch (BufferOverflowException e) { 
            System.out.println("CharSequence length is greater"
                               + " than the length of charbuffer"); 
            System.out.println("Exception throws:" + e); 
        } 
  
        catch (ReadOnlyBufferException e) { 
  
            System.out.println("Exception throws:" + e); 
        } 
    } 
}
输出： 
CharSequence length is greater than the length of charbuffer
Exception throws:java.nio.BufferOverflowException

范例3：演示ReadOnlyBufferException。

// Java program to demonstrate 
// append() method 
  
import java.nio.*; 
import java.util.*; 
  
public class GFG { 
  
    public static void main(String[] args) 
    { 
  
        // Declaring the capacity of the CharBuffer 
        int capacity = 2; 
  
        // Declaring and intializing CharSequence 
        CharSequence cha = "cow"; 
  
        // Creating the CharBuffer 
        try { 
  
            // creating object of CharBuffer 
            // and allocating size capacity 
            CharBuffer charbuffer 
                = CharBuffer.allocate(capacity); 
  
            // Creating a read-only copy of CharBuffer 
            // using asReadOnlyBuffer() method 
            CharBuffer charbuffer1 
                = charbuffer.asReadOnlyBuffer(); 
  
            // appending the CharSequence in CharBuffer 
            // using append() method 
            charbuffer1.append(cha) 
                .rewind(); 
  
            // print the CharBuffer 
            System.out.println("Original CharBuffer:  "
                               + Arrays.toString( 
                                     charbuffer1.array())); 
        } 
  
        catch (BufferOverflowException e) { 
            System.out.println("CharSequence length is greater"
                               + " than the length of charbuffer"); 
            System.out.println("Exception throws:" + e); 
        } 
  
        catch (ReadOnlyBufferException e) { 
            System.out.println("Trying to append CharSequence "
                               + "in read-only charbuffer"); 
            System.out.println("Exception throws:" + e); 
        } 
    } 
}
输出： 
Trying to append CharSequence in read-only charbuffer
Exception throws:java.nio.ReadOnlyBufferException

参考： https://docs.oracle.com/javase/9/docs/api/java/nio/CharBuffer.html#append-java.lang.CharSequence-



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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 CharBuffer append() methods in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。