多线程通信(2) 字节流中的管道流(pipeStream)是一种特殊的流,用于在不同线程之间直接传输数据 一个线程发送数据到输出管道,另一个线程从输入管道读取数据 JDK提供了四个类来使线程进行通信 1.PipedInputStream和PipedOutputStream 2.PipedReader和PipeWriter 例子: 一个用于写入流的类: public class WriterData { public void writeMethod(PipedOutputStream out){ try{ System.out.print("writer :"); for(int i = 0;i< 300;i++){ String outData = ""+i+1; out.write(outData.getBytes()); System.out.print(outData); } System.out.println(); out.close(); }catch(IOException e){ e.printStackTrace(); } } } 一个用于读取流的类: public class ReadData { public void readMethod(PipedInputStream input){ try{ System.out.print("read :"); byte[] bytes = new byte[20]; int length = input.read(bytes); while(length != -1){ String newData = new String(bytes,0,length); System.out.print(newData); length = input.read(bytes); } System.out.println(); input.close(); }catch(IOException e){ e.printStackTrace(); } } } 写入线程: public class ThreadWrite extends Thread{ private WriterData write; private PipedOutputStream out; public ThreadWrite(WriterData write,PipedOutputStream out){ this.write = write; this.out = out; } public void run(){ write.writeMethod(out); } } 读取线程: public class ThreadRead extends Thread{ private ReadData read; private PipedInputStream input; public ThreadRead(ReadData read,PipedInputStream input){ this.read = read; this.input = input; } public void run(){ read.readMethod(input); } public static void main(String[] args) { try{ WriterData writeData = new WriterData(); ReadData readData = new ReadData(); PipedInputStream inputStream = new PipedInputStream(); PipedOutputStream outputStream = new PipedOutputStream(); inputStream.connect(outputStream); ThreadRead threadread = new ThreadRead(readData,inputStream); threadread.start(); Thread.sleep(2000); ThreadWrite threadwrite = new ThreadWrite(writeData,outputStream); threadwrite.start(); }catch(IOException e){ e.printStackTrace(); }catch(InterruptedException e){ e.printStackTrace(); } } } 利用变量控制线程的顺序 用于操作a和b的类 public class DBTools { volatile private boolean preIsA = false; synchronized public void backupA(){ try{ while(preIsA == true){ wait(); } for(int i = 0;i < 5;i++){ System.out.println("*********"); } preIsA = true; notifyAll(); }catch(InterruptedException e){ e.printStackTrace(); } } synchronized public void backupB(){ try{ while(preIsA == false){ wait(); } for(int i = 0;i < 5;i++){ System.out.println("........."); } preIsA = false; notifyAll(); }catch(InterruptedException e){ e.printStackTrace(); } } } 线程a: public class BackupA extends Thread{ private DBTools dbtools; public BackupA(DBTools dbtools){ this.dbtools = dbtools; } public void run(){ dbtools.backupA(); } } 线程b: public class BackupB extends Thread{ private DBTools dbtools; public BackupB(DBTools dbtools){ this.dbtools = dbtools; } public void run(){ dbtools.backupB(); } public static void main(String[] args) { DBTools dbtools = new DBTools(); for(int i = 0;i< 20;i++){ BackupB out = new BackupB(dbtools); out.start(); BackupA in = new BackupA(dbtools); in.start(); } } }
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