Java CharArrayWriter append()用法及代码示例

Java中的CharArrayWriter类的append()方法具有三种类型：

1. Java中CharArrayWriter类的append(char)方法用于将指定的字符附加到writer。此append()方法一次将一个字符追加到CharArrayWriter并返回此CharArrayWriter.Syntax：

   public CharArrayWriter append(char c)
   
   

   指定者：此方法由Appendable接口的append()方法指定重写：此方法重写Writer类的append()方法参数：此方法接受一个参数c表示要附加的16位字符。异常：此方法不会引发任何异常。以下示例程序旨在说明IO包中CharArrayWriter类中的append(char)方法：

   Java

   // Java program to illustrate 
   // CharArrayWriter append(char) method 
     
   import java.io.*; 
     
   public class GFG { 
       public static void main(String[] args) 
       { 
     
           // Create charArrayWriter 
           CharArrayWriter charArrayWriter 
               = new CharArrayWriter(); 
     
           // Append the character 
           charArrayWriter.append('G'); 
     
           charArrayWriter.append('E'); 
     
           charArrayWriter.append('E'); 
     
           charArrayWriter.append('K'); 
     
           charArrayWriter.append('S'); 
     
           // print the charArrayWriter 
           System.out.println( 
               charArrayWriter.toString()); 
       } 
   }
   输出：

   GEEKS
   

2. Java中CharArrayWriter类的append(CharSequence)方法用于将指定的字符序列附加到writer。此append()方法一次将一个字符序列附加到CharArrayWriter并返回此CharArrayWriter.Syntax：

   
   
   

   public CharArrayWriter append(CharSequence csq)
   

   指定者：此方法由Appendable接口的append()方法指定。替代：此方法重写Writer类的append()方法。参数：该方法接受一个参数csq，该参数表示要附加的字符序列。如果字符序列为空，则将4个字符‘null’附加到CharArrayWriter中。返回值：该方法在将字符序列附加到其后返回CharArrayWriter.Exceptions：该方法不引发任何异常。以下示例程序旨在说明append(CharSequence)方法在IO包的CharArrayWriter类中：程序：

   Java

   // Java program to illustrate 
   // CharArrayWriter append(CharSequence) method 
     
   import java.io.*; 
     
   public class GFG { 
       public static void main(String[] args) 
       { 
     
           // Create charArrayWriter 
           CharArrayWriter charArrayWriter 
               = new CharArrayWriter(); 
     
           // Create character sequence 
           CharSequence csq1 = "GEEKS"; 
     
           CharSequence csq2 = "FOR"; 
     
           // Append character sequences 
           // to the charArrayWriter 
           charArrayWriter.append(csq1); 
     
           charArrayWriter.append(csq2); 
     
           charArrayWriter.append(csq1); 
     
           // print the charArrayWriter 
           System.out.println( 
               charArrayWriter.toString()); 
       } 
   }
   输出：

   GEEKSFORGEEKS
   

3. Java中CharArrayWriter类的append(CharSequence，int，int)方法用于将指定字符序列的子序列追加到writer。此append()方法将字符序列的一部分附加到CharArrayWriter并返回此CharArrayWriter.Syntax：

   public CharArrayWriter append(CharSequence csq, 
                                 int start, 
                                 int end)
   
   

   指定者：此方法由Appendable接口的append()方法指定。重写：此方法重写Writer类的append()方法参数：此方法接受三个参数：

   • csq-它表示要附加其子序列的字符序列。
   • 开始-它代表子序列的起始索引。
   • 结束-它表示子序列结尾之后的字符索引。

   返回值：异常：此方法在将给定字符序列的子序列追加到其中之后返回CharArrayWriter.Exceptions：如果开始或结尾为负或开始大于end或end大于给定字符序列的长度，则此方法引发IndexOutOfBoundsException。在IO程序包的CharArrayWriter类中说明了append(CharSequence，int，int)方法：

   Java

   // Java program to illustrate 
   // CharArrayWriter 
   // append(CharSequence, int, int) method 
     
   import java.io.*; 
     
   public class GFG { 
       public static void main(String[] args) 
       { 
     
           // Create charArrayWriter 
           CharArrayWriter charArrayWriter 
               = new CharArrayWriter(); 
     
           // Create character sequence 
           CharSequence csq = "GEEKSFORGEEKS"; 
     
           // Append subsequence of character 
           // sequence to the charArrayWriter 
           charArrayWriter.append(csq, 8, 13); 
     
           // print the charArrayWriter 
           System.out.println( 
               charArrayWriter.toString()); 
       } 
   }
   输出：

   GEEKS
   

参考文献：
1. https://docs.oracle.com/javase/10/docs/api/java/io/CharArrayWriter.html#append(char)
2. https://docs.oracle.com/javase/10/docs/api/java/io/CharArrayWriter.html#append(java.lang.CharSequence)
3. https://docs.oracle.com/javase/10/docs/api/java/io/CharArrayWriter.html#append(java.lang.CharSequence, int, int)