Javaトラフィック制御ウィジェット
開発中、ファイルアップロードダウンロードトラフィック制御の問題に遭遇することがよくあります.これは小さなプログラムで、簡単にこの機能を実現しました.参考にしてください.
コードは簡単です!
public class FlowControlInputStream extends FilterInputStream{
public static void main(String[] args){
try{
byte[] buffer = new byte[8092];
int n;
long start = System.currentTimeMillis();
FileInputStream in = new FileInputStream("E:\\pic.rar");
// 10000 10000=10kbps
FlowControlInputStream fin = new FlowControlInputStream(in, 40000);
// fin.update(1000);
System.out.println(" :"+fin.check()/1000+"kbps");
System.out.println(" :"+fin.available()/1024+"kb");
while( (n = fin.read(buffer)) > 0);
fin.close();
long end = System.currentTimeMillis();
System.out.println(" , "+(end-start)/600+" ");
}catch(IOException e){
e.printStackTrace();
}
}
private long timestamp;
private int maxbps;
private int currentbps;
private int bytesread;
//----------------------------------------------------------
//constructor
public FlowControlInputStream(InputStream in, int maxbps){
super(in);
this.maxbps = maxbps;
this.currentbps = 0;
this.bytesread = 0;
this.timestamp = System.currentTimeMillis();
}
//----------------------------------------------------------
//decorated methods
public int read() throws IOException{
synchronized(in){
int avaliable = check();
if(avaliable == 0){
waitForAvailable();
avaliable = check();
}
int value = in.read();
update(1);
return value;
}
}
public int read(byte[] b) throws IOException{
return read(b, 0, b.length);
}
public int read(byte[] b, int off, int len) throws IOException{
synchronized(in){
int avaliable = check();
if(avaliable == 0){
waitForAvailable();
avaliable = check();
}
int n = in.read(b, off, Math.min(len, avaliable));
update(n);
return n;
}
}
private int check(){
long now = System.currentTimeMillis();
if(now - timestamp >= 1000){
timestamp = now;
currentbps = bytesread;
bytesread = 0;
return maxbps;
}else{
return maxbps - bytesread;
}
}
private void waitForAvailable(){
long time = System.currentTimeMillis() - timestamp;
boolean isInterrupted = false;
while(time < 1000){
try{
Thread.sleep(1000 - time);
}catch(InterruptedException e){
isInterrupted = true;
}
time = System.currentTimeMillis() - timestamp;
}
if(isInterrupted)
Thread.currentThread().interrupt();
return;
}
private void update(int n){
bytesread += n;
}
public int getCurrentbps(){
return currentbps;
}
}
コードは簡単です!