标准java调用外部命令的写法

闲着没事写了个java调用外部命令的例子，供以后参考用，不得不说代码行比用perl多了好几个数量级

perl版本

my @result = qx(ls);
# runs command and returns its STDOUT

my @results = `ls`;
# dito, alternative syntax

system "ls";
# runs command and returns its exit status

print `ls`;
#The same, but with back quotes

exec "ls";
# replace current process with another

java版本

package com.thejtechs.systemcmd;

import java.io.IOException;
import java.util.Timer;

/**
 * 执行外部命令
 * @author thejtechs.com
 *
 */
public class SystemCmdExecutor {
	
	//这里可以构造一个Command对象作为参数，以提供更好的扩展
	public boolean execute(String cmd, long timeout, int expectReturnCode){
		boolean result = true;
		Timer timer = new Timer();
		try {
			CommandTokenizer tokenizer = new CommandTokenizer(cmd);
			Process p = Runtime.getRuntime().exec(tokenizer.tokenize());
			//为了防止JVM挂起，开启辅助线程接收和打印输出
			CommandStreamPrinter outputPrinter = new CommandStreamPrinter(p.getInputStream(), "Standard output");
			CommandStreamPrinter errorPrinter = new CommandStreamPrinter(p.getErrorStream(), "Error output");
			new Thread(outputPrinter).start();
			new Thread(errorPrinter).start();
			CommandTimeoutTask timeoutTask = new CommandTimeoutTask(p);
			timer.schedule(timeoutTask, timeout * 1000);  // Convert seconds to millis
			int returnCode = p.waitFor();
			if(expectReturnCode != returnCode){
				System.out.print("Command[" + cmd + "] execute failed, return code is : " + returnCode);
				result = false;
			}
			//正常执行完
			timeoutTask.cancel();
		} catch (IOException e) {
			//TODO log this exception
			e.printStackTrace();
			result = false;
		} catch (InterruptedException e) {
			e.printStackTrace();
			//TODO log this exception
			result = false;
		}
		timer.cancel();
		return result;
	}
	
	public static void main(String args[]){
		new SystemCmdExecutor().execute("cmd.exe /C dir C:\\Dev", 2, 0);
	}

}

package com.thejtechs.systemcmd;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.StreamTokenizer;
import java.io.StringReader;
import java.util.ArrayList;
import java.util.List;

/**
 * 分割命令字符串
 * @author thejtechs.com
 *
 */
public class CommandTokenizer {
	
	private String cmd;
	
	public CommandTokenizer(String cmd){
		this.cmd = cmd;
	}

	public String[] tokenize(){
		List cmdStrings = new ArrayList();
		try {
            StreamTokenizer sTokenizer = new StreamTokenizer(new BufferedReader(new StringReader( cmd )));
            sTokenizer.ordinaryChars('!', '~'); //'!'和'~'之间的字符时普通字符，不含任何特殊含义
            sTokenizer.wordChars('!', '~'); //'!'和'~'之间的所有字符都被当作为单词的要素。一个单词是由一个单词要素后面跟着0个或者更多个单词要素或者数字要素
            sTokenizer.ordinaryChar('\'');
            sTokenizer.ordinaryChar('\"');
            sTokenizer.quoteChar('\''); //在单引号之间的内容当做一个字符串解析
            sTokenizer.quoteChar('\"');
            while (sTokenizer.nextToken() != StreamTokenizer.TT_EOF) {
                cmdStrings.add( sTokenizer.sval );
            }
        } catch (IOException e) {
            System.out.println(e.toString());
        }
        return cmdStrings.toArray(new String[1]);
	}
	
}

package com.thejtechs.systemcmd;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;

/**
 * 打印命令执行的标准输出流和错误流的线程
 * 
 * @author thejtechs.com
 * 
 */
public class CommandStreamPrinter implements Runnable {

	private InputStream is;
	private String type;
	private String outputAsString;
	private int maxLength = 1024 * 1000; // 1MB

	public CommandStreamPrinter(InputStream is, String type) {
		this.is = is;
		this.type = type;
	}

	@Override
	public void run() {
		try {
			InputStreamReader isr = new InputStreamReader(is);
			BufferedReader br = new BufferedReader(isr);
			String line = null;
			StringBuffer sb = new StringBuffer();
			while ((line = br.readLine()) != null) {
				System.out.println(type + " >>> " + line);
				if (sb.length() < maxLength) {
					sb.append(line);
				}
			}
			outputAsString = sb.toString();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	public String getOutputAsString() {
		return outputAsString;
	}

}

package com.thejtechs.systemcmd;

import java.util.TimerTask;

/**
 * 当命令执行超时时，负责销毁任务
 * 
 * @author thejtechs.com
 * 
 */
public class CommandTimeoutTask extends TimerTask {

	private Process proc;

	public CommandTimeoutTask(Process proc) {
		this.proc = proc;
	}

	@Override
	public void run() {
		System.out.println("Process [" + proc.toString() + "] has timed out.");
		proc.destroy();

	}

}

参考： http://www.thejtechs.com/blogDetail/75/java-execute-system-command