文章目录
字节流代码演示
字符流代码演示
在Java语言中提供了各种各样的输人/输出流Stream，使我们能够很方便地对数据进行操作，其中管道流（pipeStream）是一种特殊的流，用于在不同线程间直接传送数据。一个线程发送数据到输出管道，另一个线程从输人管道中读数据。通过使用管道，实现不同线程间的通信，而无须借助于类似临时文件之类的东西。在Java的JDK中提供了4个类来使线程间可以进行通信: 字节流: PipedInputStream和PipedOutputStream 字符流: PipedReader和 PipedWriter PS: 无论使用哪一对流, 都要使俩个流(输入与输出)建立连接, 这样才可以将数据进行输出与输入
字节流
PipedInputStream和PipedOutputStream
代码演示
写数据
public class WriteStreamDate {
public void writeDate(PipedOutputStream pipedOutputStream
) {
System
.out
.println(Thread
.currentThread().getName() + " 开始向管道中写东西");
try {
for (char ch
= 'a'; ch
<= 'z'; ch
++) {
String date
= ch
+ " ";
pipedOutputStream
.write(date
.getBytes());
}
pipedOutputStream
.flush();
pipedOutputStream
.close();
System
.out
.println(Thread
.currentThread().getName() + " 写数据完毕");
} catch (IOException e
) {
e
.printStackTrace();
}
}
}
读数据
public class ReadStreamDate {
public void readDate(PipedInputStream pipedInputStream
) {
System
.out
.println(Thread
.currentThread().getName() + " 开始从管道中读数据");
byte[] buffer
= new byte[20];
int len
= -1;
try {
while ((len
= (pipedInputStream
.read(buffer
))) != -1) {
String date
= new String(buffer
, 0, len
);
System
.out
.print(date
);
}
System
.out
.println();
pipedInputStream
.close();
System
.out
.println(Thread
.currentThread().getName() + " 读完毕");
} catch (IOException e
) {
e
.printStackTrace();
}
}
}
运行
public class Run {
public static void main(String
[] args
) throws IOException
, InterruptedException
{
PipedInputStream pipedInputStream
= new PipedInputStream();
PipedOutputStream pipedOutputStream
= new PipedOutputStream();
pipedInputStream
.connect(pipedOutputStream
);
WriteStreamDate writeStreamDate
= new WriteStreamDate();
ReadStreamDate readStreamDate
= new ReadStreamDate();
Thread a
= new Thread("A") {
@Override
public void run() {
writeStreamDate
.writeDate(pipedOutputStream
);
}
};
Thread b
= new Thread("B") {
@Override
public void run() {
readStreamDate
.readDate(pipedInputStream
);
}
};
b
.start();
Thread
.sleep(100);
a
.start();
Thread
.sleep(100);
}
}
运行结果 上述代码首先是读取线程启动，由于当时没有数据被写人，所以线程阻塞在len = (pipedInputStream.read(buffer);代码中，直到有数据被写入并且执行colse方法，才继续向下运行。当然如果是写线程先启动就没这个问题.
字符流
PipedReader和 PipedWriter
代码演示
写数据
public class WriteDate {
public void write(PipedWriter pipedWriter
) {
System
.out
.println(Thread
.currentThread().getName() + " 开始写数据");
StringBuilder date
= new StringBuilder();
try {
for (char ch
= 'a'; ch
<= 'g'; ch
++) {
date
.append(ch
);
pipedWriter
.write(date
.toString() + " ");
}
pipedWriter
.flush();
pipedWriter
.close();
System
.out
.println(Thread
.currentThread().getName() + " 写数据完毕");
} catch (IOException e
) {
e
.printStackTrace();
}
}
}
读数据
public class ReadDate {
public void read(PipedReader pipedReader
) {
System
.out
.println(Thread
.currentThread().getName() + " 开始读数据");
char[] buffer
= new char[20];
int len
= -1;
try {
while ((len
= pipedReader
.read(buffer
)) != -1) {
String date
= new String(buffer
, 0, len
);
System
.out
.println(date
);
}
pipedReader
.close();
System
.out
.println(Thread
.currentThread().getName() + " 读数据完毕");
} catch (IOException e
) {
e
.printStackTrace();
}
}
}
运行类
public class Run2 {
public static void main(String
[] args
) throws IOException
, InterruptedException
{
PipedReader pipedReader
= new PipedReader();
PipedWriter pipedWriter
= new PipedWriter();
pipedReader
.connect(pipedWriter
);
ReadDate readDate
= new ReadDate();
WriteDate writeDate
= new WriteDate();
Thread a
= new Thread("A") {
@Override
public void run() {
writeDate
.write(pipedWriter
);
}
};
Thread b
= new Thread("B") {
@Override
public void run() {
readDate
.read(pipedReader
);
}
};
a
.start();
Thread
.sleep(100);
b
.start();
Thread
.sleep(100);
}
}
执行结果 这个代码如果是读线程提前, 问题和字节流是一样的, 依旧会阻塞在len = (pipedInputStream.read(buffer)
