public DownFile(String picUrl) {
this.picUrl = picUrl;
System.out.println(picUrl);
} private void Down(){
try {
URL url = new URL(picUrl);
URLConnection conn = url.openConnection();
conn.connect();
ds = new DataInputStream(conn.getInputStream());
out = new DataOutputStream(new FileOutputStream("01.jpg"));
int temp;
while((temp=ds.read())!=-1){
System.out.println(temp);
out.wait(temp);
}
out.close();
ds.close();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
}

public static void main(String s[]){
DownFile d = new DownFile("http://zi.csdn.net/300601.gif");
d.Down();
}写入出问题了