Java调用批处理文件(.bat)

java在执行.bat文件时,经常会出现卡住不动的状况,我们称之为阻塞.

发生阻塞的诱因是java执行bat文件,在使用Runtime.getRuntime.exec(“xx:/xxxx.bat”)时,会有outputStream,ErrStream,InputStream三个IO流,如果这三个IO流都有数据的传输操作,那么需要对每一个IO流进行处理,如果有一个IO流漏处理了,那么程序将无限期的期待该IO流被处理,继而程序阻塞.

下面,已java打开安装apache2.2的.bat文件为例,说明一下如何处理阻塞.

public class TestApache {

public static void main(String[] args) {

try {

final CountDownLatch threadSignal = new CountDownLatch(2);//初始化countDown

System.out.println("Start ......");

final Process pro = Runtime.getRuntime().exec("cmd /c \"c:\\start.bat\"");

pro.getOutputStream().close();

Runnable errThread = new Runnable() {

@Override

public void run() {

try {

InputStream is = pro.getErrorStream();

InputStreamReader isr = new InputStreamReader(is);

BufferedReader br = new BufferedReader(isr);

String line = "";

StringBuilder sb = new StringBuilder();

while((line = br.readLine()) != null) {

sb.append(line);

}

System.out.println("error : " + sb.toString());

} catch (IOException e) {

e.printStackTrace();

}

threadSignal.countDown();//线程结束时计数器减1

}

};

new Thread(errThread).start();

Runnable inputThread = new Runnable() {

@Override

public void run() {

try {

InputStream is = pro.getInputStream();

InputStreamReader isr = new InputStreamReader(is);

BufferedReader br = new BufferedReader(isr);

String line = "";

StringBuilder sb = new StringBuilder();

while((line = br.readLine()) != null) {

sb.append(line);

}

System.out.println("input : " + sb.toString());

is.close();

isr.close();

br.close();

} catch (IOException e) {

e.printStackTrace();

}

threadSignal.countDown();//线程结束时计数器减1

}

};

new Thread(inputThread).start();

try {

threadSignal.await();

} catch (InterruptedException e) {

e.printStackTrace();

}

System.out.println("=========================");

Runtime.getRuntime().exec("cmd /c net start apache2.2");

System.out.println("cmd /c net start apache2.2");

} catch (IOException e) {

e.printStackTrace();

}

}

}

复制代码

关于OutputStream,程序用不到,直接在起初的之后就需要close掉.对于errStream & inputStream应该分别用一个线程来调用出IO流中的内容.

注意:必须使用线程java执行bat文件,否则永远会阻塞.

final CountDownLatch threadSignal = new CountDownLatch(2);//初始化countDown

这一个栏位是用来让主线程等待两个子线程执行完毕用的.

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