Java用文件流下载网络文件示例代码

public httpservletresponse download(string path, httpservletresponse response) {
        try {
            // path是指欲下载的文件的路径。
            file file = new file(path);
            // 取得文件名。
            string filename = file.getname();
            // 取得文件的后缀名。
            string ext = filename.substring(filename.lastindexof(".") + 1).touppercase();

            // 以流的形式下载文件。
            inputstream fis = new bufferedinputstream(new fileinputstream(path));
            byte[] buffer = new byte[fis.available()];
            fis.read(buffer);
            fis.close();
            // 清空response
            response.reset();
            // 设置response的header
            response.addheader("content-disposition", "attachment;filename=" + new string(filename.getbytes()));
            response.addheader("content-length", "" + file.length());
            outputstream toclient = new bufferedoutputstream(response.getoutputstream());
            response.setcontenttype("application/octet-stream");
            toclient.write(buffer);
            toclient.flush();
            toclient.close();
        } catch (ioexception ex) {
            ex.printstacktrace();
        }
        return response;
    }

    public void downloadlocal(httpservletresponse response) throws filenotfoundexception {
        // 下载本地文件
        string filename = "operator.doc".tostring(); // 文件的默认保存名
        // 读到流中
        inputstream instream = new fileinputstream("c:/operator.doc");// 文件的存放路径
        // 设置输出的格式
        response.reset();
        response.setcontenttype("bin");
        response.addheader("content-disposition", "attachment; filename=\"" + filename + "\"");
        // 循环取出流中的数据
        byte[] b = new byte[100];
        int len;
        try {
            while ((len = instream.read(b)) > 0)
                response.getoutputstream().write(b, 0, len);
            instream.close();
        } catch (ioexception e) {
            e.printstacktrace();
        }
    }

    public void downloadnet(httpservletresponse response) throws malformedurlexception {
        // 下载网络文件
        int bytesum = 0;
        int byteread = 0;

        url url = new url("windine.blogdriver.com/logo.gif");

        try {
            urlconnection conn = url.openconnection();
            inputstream instream = conn.getinputstream();
            fileoutputstream fs = new fileoutputstream("c:/abc.gif");

            byte[] buffer = new byte[1204];
            int length;
            while ((byteread = instream.read(buffer)) != -1) {
                bytesum += byteread;
                system.out.println(bytesum);
                fs.write(buffer, 0, byteread);
            }
        } catch (filenotfoundexception e) {
            e.printstacktrace();
        } catch (ioexception e) {
            e.printstacktrace();
        }
    }