Java CharBuffer append()用法及代碼示例

append(char c)

java.nio.CharBuffer類的append(char c)方法用於將指定的char附加到此緩衝區(可選操作)。調用dst.append(c)形式的方法的行為與調用dst.put(c)的行為完全相同

用法:

public CharBuffer append(char c)

參數：此方法需要附加16位char。

返回值：此方法返回此緩衝區，在其中插入char值。

異常：此方法引發以下異常：

BufferOverflowException-如果此緩衝區中的空間不足
ReadOnlyBufferException-如果此緩衝區是隻讀的

下麵的示例說明了append(char c)方法：

範例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); 
        } 
    } 
}

輸出：

Original CharBuffer: [a, b, c]

範例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); 
        } 
    } 
}

輸出：

Original CharBuffer: [a, b, c]

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

範例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); 
        } 
    } 
}

輸出：

Original CharBuffer: [a, b, c]

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

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

append(CharSequence csq)

java.nio.CharBuffer類的append(CharSequence csq)方法用於將指定的字符序列追加到此緩衝區(可選操作)。

根據字符序列csq的toString規範，可能不會附加整個序列。例如，調用字符緩衝區的toString方法將返回一個子序列，其內容取決於緩衝區的位置和限製。

用法:

public CharBuffer append(CharSequence csq)

參數：此方法將字符序列追加。如果csq為null，則將四個字符“null”附加到此字符緩衝區。

返回值：此方法返回此緩衝區。

異常：此方法引發以下異常：

BufferOverflowException-如果此緩衝區中的空間不足
ReadOnlyBufferException-如果此緩衝區是隻讀的

以下示例說明了append(CharSequence csq)方法：

範例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); 
        } 
    } 
}

輸出：

Original CharBuffer:

範例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); 
        } 
    } 
}

輸出：

CharSequence length is greater than the length of charbuffer
Exception throws:java.nio.BufferOverflowException

範例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); 
        } 
    } 
}

輸出：

Trying to append CharSequence in read-only charbuffer
Exception throws:java.nio.ReadOnlyBufferException

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

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 CharBuffer append() methods 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。