java 判断程序是否正在运行

 

public class ProcessBuilder {

 

/**

* 进程运行标记文件名称

*/

public final String SIGN_RUN_FILE_NAME = "run.do";

 

private static Logger log = Logger.getLogger(ProcessBuilder.class);

 

/**

* 创建进程

* 

* @param cmd

*            命令行

* @param workDir

*            指定的工作目录

* @throws IOException

*/

public Process create(String[] cmd, File dir) throws Exception {

// 执行命令行,创建新的进程

Process ps = Runtime.getRuntime().exec(cmd, null, dir);

if (ps != null) {

//  （非常重要）输出进程流中的信息，防止运行过程中因为进程流的阻塞，导致被迫挂起

                        new ProcessStreamUtil(ps.getErrorStream(), "ERROR").start();

new ProcessStreamUtil(ps.getInputStream(), "OUTPUT").start();

return ps;

}

return null;

}

 

/**

* 标记进程的运行 (注:在运行主目录下创建一个目标文件,并加上文件锁, 用于当外部程通过文件锁来判断程序是否正在运行)

* 

* @return

*/

public boolean signRunning() throws Exception {

// 运行目录

String lockPath = System.getProperty("user.dir");

File dir = new File(lockPath);

if (!dir.exists()) {

dir.mkdirs();

}

// 待锁定的目标文件路径

lockPath = lockPath + File.separator + SIGN_RUN_FILE_NAME;

log.debug("标记文件:" + lockPath);

 

return this.tryLockFile(lockPath);

}

 

/**

* 通过文件锁来判断程序是否正在运行

* 

* @return 如果正在运行返回true，否则返回false

*/

public boolean isRunning(String lockFilePath) throws Exception {

log.debug("嗅探文件:" + lockFilePath);

int i = 0;

// 延时60秒,嗅探目标文件是否已被锁上

do {

if (i++ > 20) {

return false;

}

 

if (!this.tryLockFile(lockFilePath)) {

return true;

} else {

Thread.sleep(3 * 1000L);

}

} while (true);

}

 

/**

* 尝试对目标文件进行加锁操作

* 

* @param lockFilePath

*            目标文件

* @return

*/

private boolean tryLockFile(String lockFilePath) throws Exception {

// 待锁定的目标文件路径

log.debug(lockFilePath);

 

RandomAccessFile fis = null;

FileLock flock = null;

FileChannel lockfc = null;

try {

fis = new RandomAccessFile(lockFilePath, "rw");

lockfc = fis.getChannel();

// 尝试加锁

flock = lockfc.tryLock();

if (flock != null) {

return true;

}

} finally {

// 释放资源

if (fis != null)

fis.close();

if (flock != null)

lockfc.close();

}

 

return false;

}

 

}

 

 

// 进程流输出工具类

 

public class ProcessStreamUtil extends Thread {

private Logger log = Logger.getLogger(ProcessStreamUtil.class);

private InputStream is = null;

private String type = null;

 

public ProcessStreamUtil(InputStream is, String type) {

this.is = is;

this.type = type;

}

 

public void run() {

log.debug(type + "......");

InputStreamReader isr = null;

BufferedReader br = null;

try {

isr = new InputStreamReader(is);

br = new BufferedReader(isr);

String line = null;

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

log.debug(type + ">" + line);

}

} catch (Exception ioe) {

log.error(ioe);

} finally {

try {

if (isr != null)

isr.close();

if (br != null)

br.close();

} catch (Exception er) {

log.error(er);

}

}

}

}