java线程间通信之通过管道进行通信

管道流PipeStream是一种特殊的流，用于在不同线程间直接传送数据，而不需要借助临时文件之类的东西。

jdk中提供了四个类来使线程间可以通信：

1）PipedInputStream和PipedOutputStream

2）PipedReader和PipedWriter

先看看字节流的示例：

 1 public class ReadData {
 2     
 3     public void readMethod(PipedInputStream in) throws IOException{
 4         System.out.println("begin read...");
 5         byte[] b = new byte[20];
 6         int readLength = in.read(b);
 7         while (readLength != -1) {
 8             String newData = new String(b, 0, readLength);
 9             System.out.println("read:"+newData);
10             readLength = in.read(b);
11         }
12         in.close();
13         System.out.println("end read...");
14     }
15 
16 }

 1 public class WriteData {
 2 
 3     public void writeMethod(PipedOutputStream out) throws IOException{
 4         System.out.println("begin write...");
 5         for (int i = 0; i < 10; i++) {
 6             out.write((""+i).getBytes());
 7             System.out.println("write:"+i);
 8         }
 9         out.close();
10         System.out.println("end write...");
11     }
12 }

 1 public class ThreadRead extends Thread {
 2     
 3     private ReadData readData;
 4     private PipedInputStream in;
 5 
 6     public ThreadRead(ReadData readData, PipedInputStream in) {
 7         this.readData = readData;
 8         this.in = in;
 9     }
10     
11     @Override
12     public void run() {
13         try {
14             readData.readMethod(in);
15         } catch (IOException e) {
16             e.printStackTrace();
17         }
18     }
19 }

 1 public class ThreadWrite extends Thread {
 2     
 3     private WriteData writeData;
 4     private PipedOutputStream out;
 5     
 6     public ThreadWrite(WriteData writeData, PipedOutputStream out) {
 7         this.writeData = writeData;
 8         this.out = out;
 9     }
10 
11     @Override
12     public void run() {
13         try {
14             writeData.writeMethod(out);
15         } catch (IOException e) {
16             e.printStackTrace();
17         }
18     }
19 }

 1 public class Run {
 2     public static void main(String[] args) throws IOException, InterruptedException {
 3         WriteData writeData = new WriteData();
 4         ReadData readData = new ReadData();
 5         
 6         PipedOutputStream out = new PipedOutputStream();
 7         PipedInputStream in = new PipedInputStream();
 8         
 9         in.connect(out);
10         
11         new ThreadWrite(writeData, out).start();
12         Thread.sleep(2000);
13         new ThreadRead(readData, in).start();
14     }
15 }

再看看字符流示例：

 1 public class ReadData {
 2     
 3     public void readMethod(PipedReader reader) throws IOException{
 4         System.out.println("begin read...");
 5         char[] c = new char[20];
 6         int readLength = reader.read(c);
 7         while (readLength != -1) {
 8             String newData = new String(c, 0, readLength);
 9             System.out.println("read:"+newData);
10             readLength = reader.read(c);
11         }
12         reader.close();
13         System.out.println("end read...");
14     }
15 
16 }

 1 public class WriteData {
 2 
 3     public void writeMethod(PipedWriter writer) throws IOException{
 4         System.out.println("begin write...");
 5         for (int i = 0; i < 10; i++) {
 6             writer.write((""+i));
 7             System.out.println("write:"+i);
 8         }
 9         writer.close();
10         System.out.println("end write...");
11     }
12 }

 1 public class ThreadRead extends Thread {
 2     
 3     private ReadData readData;
 4     private PipedReader reader;
 5 
 6     public ThreadRead(ReadData readData, PipedReader reader) {
 7         this.readData = readData;
 8         this.reader = reader;
 9     }
10     
11     @Override
12     public void run() {
13         try {
14             readData.readMethod(reader);
15         } catch (IOException e) {
16             e.printStackTrace();
17         }
18     }
19 }

 1 public class ThreadWrite extends Thread {
 2     
 3     private WriteData writeData;
 4     private PipedWriter writer;
 5     
 6     public ThreadWrite(WriteData writeData, PipedWriter writer) {
 7         this.writeData = writeData;
 8         this.writer = writer;
 9     }
10 
11     @Override
12     public void run() {
13         try {
14             writeData.writeMethod(writer);
15         } catch (IOException e) {
16             e.printStackTrace();
17         }
18     }
19 }

 1 public class Run {
 2     public static void main(String[] args) throws IOException, InterruptedException {
 3         WriteData writeData = new WriteData();
 4         ReadData readData = new ReadData();
 5         
 6         PipedWriter writer = new PipedWriter();
 7         PipedReader reader = new PipedReader();
 8         
 9         writer.connect(reader);
10         
11         new ThreadWrite(writeData, writer).start();
12         Thread.sleep(2000);
13         new ThreadRead(readData, reader).start();
14     }
15 }