java执行bat阻塞的解决方法
java在执行.bat文件时,经常会出现卡住不动的情况,我们称之为阻塞.
发生阻塞的原因是,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,那么必须对每一个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等待该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.
package com.multiable.util;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.util.concurrent.CountDownLatch;public class TestApache {public static void main(String[] args) {try {final CountDownLatch threadSignal = new CountDownLatch(2);//初始化countDownSystem.out.println("Start ......");final Process pro = Runtime.getRuntime().exec("cmd /c "c:\\start.bat"");pro.getOutputStream().close();Runnable errThread = new Runnable() {@Overridepublic 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() {@Overridepublic 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();}}}