通过TCP连接传输mp3文件。使用JProgressBar

Question

显示下载进度我正在通过TCP连接发送一个mp3文件的程序。我正在尝试使用JProgressBar来显示下载进度。但是，在完全下载文件之前，我不知道文件大小。无论如何，我可以在从服务器端下载文件之前获取文件大小？

在此先感谢。这里是我的代码

SERVER：

PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true); 
dataOut = new BufferedOutputStream(clientSocket.getOutputStream()); 
file = new File(LIBRARY, data); 
//get length of file 
int fileLength = (int)file.length(); 

fileData = new byte[fileLength]; 
fileIn = new FileInputStream(file); 
BufferedInputStream bis = new BufferedInputStream(fileIn); 
bis.read(fileData, 0 , fileData.length); 
OutputStream os = clientSocket.getOutputStream(); 
os.write(fileData, 0 , fileData.length); 
os.flush(); 
clientSocket.close(); 

客户：

int filesize=999999999; //A TEMPORARY FILE SIZE 

long start = System.currentTimeMillis(); 
int bytesRead; 
int current = 0; 
// localhost for testing 
Socket sock = new Socket(SERVER_NAME,DEST_PORT); 
PrintWriter out = new PrintWriter(sock.getOutputStream(), true); 
// receive file 
byte [] mybytearray = new byte [filesize]; 
out.println(request); 
InputStream is = sock.getInputStream(); 
FileOutputStream fos = new FileOutputStream(request); 
BufferedOutputStream bos = new BufferedOutputStream(fos); 
bytesRead = is.read(mybytearray,0,mybytearray.length); 
current = bytesRead; 
System.out.println(bytesRead); 

do { 
     bytesRead = is.read(mybytearray, current, (mybytearray.length-current)); 
     if(bytesRead >= 0) current += bytesRead; 
} while(bytesRead > -1); 

bos.write(mybytearray, 0 , current); 
bos.flush(); 
long end = System.currentTimeMillis(); 
System.out.println(current); 
bos.close(); 
sock.close(); 

Answer 1

解决： 的解决方案是不是很难实际。我只是在发送文件之前发送文件大小。所以，客户端收到的文件大小将其最大值设置为文件大小JProgressBar.setMaximum（fileLength）;然后使用setValue（）增加进度条的值; 这里是我更新的代码：

SERVER：

PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true); 

dataOut = new BufferedOutputStream(clientSocket.getOutputStream()); 
file = new File(LIBRARY, data); 
//get length of file 
int fileLength = (int)file.length(); 

out.println(fileLength);// this sends the file length 

fileData = new byte[fileLength]; 
fileIn = new FileInputStream(file); 
BufferedInputStream bis = new BufferedInputStream(fileIn); 
bis.read(fileData, 0 , fileData.length); 
OutputStream os = clientSocket.getOutputStream(); 
os.write(fileData, 0 , fileData.length); 
os.flush(); 
clientSocket.close(); 

客户：

progressBar.setValue(0); 
int bytesRead; 
int current = 0; 
// localhost for testing 
Socket sock = new Socket(SERVER_NAME,DEST_PORT); 
PrintWriter out = new PrintWriter(sock.getOutputStream(), true); 
// receive file 
BufferedReader in = new BufferedReader(new InputStreamReader(sock.getInputStream())); //CREATE BUFFERED READER TO READ THE FILE SIZE 
out.println(request); 
InputStream is = sock.getInputStream(); 
FileOutputStream fos = new FileOutputStream(request); 
BufferedOutputStream bos = new BufferedOutputStream(fos); 
int fileLen = Integer.parseInt(in.readLine()); 
progressBar.setMaximum(fileLen); // READ THE FILE SIZE 
byte [] byteArray = new byte [fileLen+100]; //SET THE BYTEARRAY 100 BYTES EXTRA 
bytesRead = is.read(byteArray,0,byteArray.length); 
current = bytesRead; 
do { 
     bytesRead = is.read(byteArray, current, (byteArray.length-current)); 
     if(bytesRead >= 0) current += bytesRead; 
     progressBar.setValue(current); 
} while(bytesRead > -1); 

bos.write(byteArray, 0 , current); 
bos.flush(); 
//System.out.println(current); 
bos.close(); 
fos.close(); 
in.close(); 
is.close(); 
sock.close();