Java Java.io.PipedWriter用法及代码示例

这个类本质上是一个管道character-output流。在输入/输出中管道式，简单来说就是JVM中同时运行的两个线程之间的链接。因此，管道既可以用作源也可以用作目标。
如果向连接的管道输出流提供数据字节的线程不再活动，则称管道已损坏。

声明：

public class PipedWriter
  extends Writer

构造函数：

• PipedWriter():创建一个 PipedWriter，它未连接。
• PipedWriter(PipedReader inStream)：创建一个 PipedWriter，它连接到 PipedReader - ‘inStream’。

方法：

• 写(int char):java.io.PipedWriter.write(int char)将指定字符写入 PipedWriter。
  Syntax :

  public void write(int char)
  Parameters : 
  char : character to be written
  Return :                                               
  void
  Exception :
  -> IOException : if in case IO error occurs.

• write(char[] carray, int 偏移量, int maxlen):java.io.PipedWriter.write(char[] carray, int 偏移量, int maxlen)将 ‘carray’ 中的 maxlen 字符写入 PipedWriter。如果没有剩余字符要写入 Stream，则该方法将阻塞。
  Syntax :

  public void write(char[] carray, int offset, int maxlen)
  Parameters : 
  carray : data of the carray
  offset : starting in the destination array - 'carray'.
  maxlen : maximum length of array to be read
  Return :                                               
  void
  Exception :
  -> IOException : if in case IO error occurs.

  执行：

  
  // Java program illustrating the working of PipedWriter 
  // write(char[] carray, int offset, int maxlen) 
    
  import java.io.*; 
  public class NewClass 
  { 
      public static void main(String[] args) throws IOException 
      { 
          PipedReader geek_reader = new PipedReader(); 
          PipedWriter geek_writer = new PipedWriter(); 
    
          // Use of connect() : connecting geek_reader with geek_writer 
          geek_reader.connect(geek_writer); 
    
          char[] carray = {'J', 'A', 'V', 'A'}; 
    
          // Use of write(char[] carray, int offset, int maxlen) 
          geek_writer.write(carray, 0, 4); 
          int a = 5; 
          System.out.print("Use of write(carray, offset, maxlen) : "); 
          while(a>0) 
          { 
              System.out.print(" " + (char) geek_reader.read());           
          } 
          
      } 
  } 

  输出：

  Use of write(carray, offset, maxlen) :  J A V A

• close():java.io.PipedWriter.close()关闭PipedWriter并释放分配的资源。
  Syntax :

  public void close()
  Parameters : 
  --------------
  Return :                                               
  void
  Exception :
  -> IOException : if in case IO error occurs.

• 连接(PipedReader 目的地)：java.io.PipedWriter.connect(PipedReader 目的地)将 PipedWriter 连接到 ‘destination’ PipedReader，如果 ‘destination’ 是带有其他流的管道，则会引发 IO 异常
  Syntax :

  public void connect(PipedReader destination)
  Parameters : 
  destination : the PipedReader to be connected to
  Return :                                               
  void
  Exception :
  -> IOException : if in case IO error occurs.

• flush():java.io.PipedWriter.flush()刷新输出流。
  Syntax :

  public void flush()
  Parameters : 
  ------------
  Return :                                               
  void
  Exception :
  -> IOException : if in case IO error occurs.

  说明 PipedWriter 类方法工作的 Java 代码：

  
  // Java program illustrating the working of PipedWriter 
  // write(), connect 
  // close(), flush() 
    
  import java.io.*; 
  public class NewClass 
  { 
      public static void main(String[] args) throws IOException 
      { 
          PipedReader geek_reader = new PipedReader(); 
          PipedWriter geek_writer = new PipedWriter(); 
          try
          { 
              // Use of connect() : connecting geek_reader with geek_writer 
              geek_reader.connect(geek_writer); 
    
              // Use of write(int byte) : 
              geek_writer.write(71); 
              geek_writer.write(69); 
              geek_writer.write(69); 
              geek_writer.write(75); 
              geek_writer.write(83); 
    
              // Use of flush() method : 
              geek_writer.flush(); 
              System.out.println("Use of flush() method : "); 
    
              int i = 5; 
              while(i > 0) 
              { 
                  System.out.print(" " + (char) geek_reader.read()); 
                  i--; 
              } 
    
              // USe of close() method : 
              System.out.println("\nClosing the Writer stream"); 
              geek_writer.close(); 
    
          } 
          catch (IOException excpt) 
          { 
              excpt.printStackTrace(); 
          } 
      } 
  } 

  输出：

  Use of flush() method : 
   G E E K S
  Closing the Writer stream

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