如何用nodejs实现一定时间的文件监控

　　function watchResponseFile(filePath, num, response) {
　　if (num < 10) {

fs.exists(filePath, function (exists) {

if (exists) {

fs.readFile(filePath, "utf-8", function (err, data) {

if (!err) {

response.writeHead(200, { "Content-Type": "text/json" });

response.write(data);

response.end();

}

else {

response.writeHead(200, { "Content-Type": "text/json" });

response.write("fail:" + err);

response.end();

}

//删除响应文件

fs.unlink(filePath, function (err) {

});

});

}

else {

num = num + 1;

setTimeout(watchResponseFile(filePath, num, response), 10000);

}

});

}