Question

java文件下载的问题

以前没写过文件下载的程序，现在在servlet中试了试，有些问题请教大神。代码如下：

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

response.setContentType("text/html");
response.setCharacterEncoding("utf-8");
// String path = request.getParameter("path");
String path = "F:\\OKDownLoad\\854546_e472e815bf086a04a78173d95c90b760_1369553818.gif";
//读到流中
InputStream ins = new FileInputStream(path);
//设置输出的格式
response.reset();
response.setContentType("bin");
response.addHeader("Content-Disposition", "attachment; filename=\"下载测试\"");

//循环取出流中的数据
byte[] b = new byte[100];
int len = ins.read(b);
ins.close();
try {
while(len > 0){
response.getOutputStream().write(b, 0, len);
ins.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}

这样下载的时候，会弹出下载狂，但是就一直卡在0%，下载不动，一点击取消，就报出ClientAbortException: java.net.SocketException: Connection reset by peer: socket write error异常，各位大神指教指教啊。

Answer 1

package timing;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
/**
 * @author Hardneedl
 */
public class DownloadServlet extends HttpServlet{
    private File file;
    public void init(ServletConfig config) throws ServletException {
        super.init(config);
        
        /*<servlet>
                <servlet-name>downloadFile</servlet-name>
                <servlet-class>timing.DownloadServlet</servlet-class>
                <init-param>
                    <param-name>demoFile</param-name>
                    <param-value>g:\\workflows.xml</param-value>
                </init-param>
            </servlet>*/
        file=new File(config.getInitParameter("demoFile"));
    }
    protected void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException {
        res.reset();
        res.setContentType("bin");
        res.addHeader("Content-Disposition", "attachment; filename=\"下载测试\"");
        final InputStream ins = new FileInputStream(file);
        final OutputStream outs=res.getOutputStream();
        byte[]buf=new byte[1024*20];
        int r;
        while( (r=ins.read(buf))!=-1 ){
            outs.write(buf,0,r);
            outs.flush();
        }
        outs.flush();
        ins.close();
        outs.close();
    }
}

Answer 2

循环是个死循环