我有一个多线程进程，5个线程，另一个线程作为状态对象报告BlockingQueue的大小。问题是状态线程首先报告100％，这是正确的，但后来直接报告为0％。
我希望它能倒数百分比。
这是我的代码：
Thread[] workers = new Thread[NUMBER_OF_THREADS];
for (int x = 0; x < NUMBER_OF_THREADS; x++) {
workers[x] = new Thread(new S3ObjectDownloader(filesToDownload, currentYear));
workers[x].start();
}
for (int x = 0; x < NUMBER_OF_THREADS; x++) {
try {
workers[x].join();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
这是状态对象实例化：
int downloadSize = filesToDownload.size();
Thread statusThread = new Thread(new Status(filesToDownload, currentYear,downloadSize,"DOWNLOADING..."));
statusThread.start();
这是实际的Status对象运行方法：
public void run() {
while(!queue.isEmpty()){
try {
float completion = (queue.size()*1)/this.queueSize;
System.out.println(this.jobeName+" : "+this.conferenceYear+ " completion..."+MessageFormat.format("{0,number,#.##%}",completion));
TimeUnit.SECONDS.sleep(30);;
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
我添加了实际的S3ObjectDownloader：
public void run() {
//aws credentials
this.s3 = new AmazonS3Client(new ClasspathPropertiesFileCredentialsProvider());
//log4j configuration
PropertyConfigurator.configure("/home/ubuntu/log4j.properties");
//attempt to poll the queue
while (!queue.isEmpty()) {
String fileName = queue.poll() + ".mp4";
String FULL_PATH = "best_of_ats/" + this.conferenceYear + "/videos/" + fileName;
File f = new File("/home/ubuntu/" + fileName);
if (fileName != null && !f.exists() && s3.doesObjectExist(BUCKET_NAME, FULL_PATH)) {
OutputStream out = null;
InputStream in = null;
S3Object s3obj = null;
try {
s3obj = s3.getObject(this.BUCKET_NAME,
FULL_PATH);
in = s3obj.getObjectContent();
//System.out.println("Downloading File " + FULL_PATH + "....");
} catch (AmazonS3Exception s3e) {
// s3e.printStackTrace();
//System.out.println("Problem downloading file..." + FULL_PATH);
s3e.printStackTrace();
logger.info("Problem with file..." + FULL_PATH);
continue;
}
try {
out = new FileOutputStream(new File(fileName));
int read = 0;
byte[] bytes = new byte[1024];
while ((read = in.read(bytes)) != -1) {
out.write(bytes, 0, read);
}
out.flush();
out.close();
in.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
//System.out.println("problem writing output..." + FULL_PATH);
logger.info("problem writing output..." +FULL_PATH);
continue;
}
}
} // end while...
}
这是状态类：
public class Status implements Runnable {
private String conferenceYear;
private Queue<String>queue;
private int queueSize;
private String jobeName;
public Status(Queue<String> queue, String conferenceYear, int queueSize, String jobName){
this.conferenceYear = conferenceYear;
this.queue = queue;
this.queueSize = queueSize;
this.jobeName = jobName;
}
@Override
public void run() {
while(!queue.isEmpty()){
try {
float completion = (queue.size()*1)/this.queueSize;
System.out.println(this.jobeName+" : "+this.conferenceYear+ " completion..."+MessageFormat.format("{0,number,#.##%}",completion));
TimeUnit.SECONDS.sleep(30);;
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
这是调用类：
public static void main(String[] args) {
BlockingQueue<String> filesToDownload = new LinkedBlockingDeque<String>(1024);
BlockingQueue<String> filesToPreview = new LinkedBlockingDeque<String>(1024);
BlockingQueue<String> filesToUpload = new LinkedBlockingDeque<String>(1024);
String currentYear = String.valueOf(Calendar.getInstance().get(Calendar.YEAR));
// DB connection.
ATSStoreDB db = new ATSStoreDB();
PreparedStatement st = null;
Connection conn = null;
conn = db.getConnection();
// get ids from ats_store.products.
try {
st = conn.prepareStatement(sql);
st.setString(1, currentYear);
ResultSet rs = st.executeQuery();
// add each id to IDS.
while (rs.next()) {
filesToDownload.add(rs.getString("product_id"));
filesToPreview.add(rs.getString("product_id"));
filesToUpload.add(rs.getString("product_id"));
}
conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
/*
* Distribute IDS to several threads.
*/
//start up the Status Object class.
int downloadSize = filesToDownload.size();
Thread statusThread = new Thread(new Status(filesToDownload, currentYear,downloadSize,"DOWNLOADING..."));
statusThread.start();
/**
* download the files
*/
Thread[] workers = new Thread[NUMBER_OF_THREADS];
for (int x = 0; x < NUMBER_OF_THREADS; x++) {
workers[x] = new Thread(new S3ObjectDownloader(filesToDownload, currentYear));
workers[x].start();
}
for (int x = 0; x < NUMBER_OF_THREADS; x++) {
try {
workers[x].join();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* create previews
*/
int previewSize = filesToPreview.size();
statusThread = new Thread(new Status(filesToPreview, currentYear,previewSize,"PREVIEWING..."));
statusThread.start();
workers = new Thread[NUMBER_OF_THREADS];
for (int x = 0; x < NUMBER_OF_THREADS; x++) {
workers[x] = new Thread(new Worker(filesToPreview, currentYear));
workers[x].start();
}
for (int x = 0; x < NUMBER_OF_THREADS; x++) {
try {
workers[x].join();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
答案 0 :(得分：0)
我可以立即发现您的代码存在一个问题：
float completion = (queue.size()*1)/this.queueSize;
*1的重点是什么？ queue.size()和this.queueSize都是整数。你将整数除法变成了整数除法。一个好的编译器可能会立即优化它。你可能想写一些像
float completion = (queue.size() * 1.0f) / this.queueSize;