JSP文件下载（不使用jar包）

 

java代码：

public class download extends httpservlet {

    public download() {
        super();
    }

    public void destroy() {
        super.destroy(); // just puts destroy string in log
        // put your code here
    }

    public void doget(httpservletrequest request, httpservletresponse response)
            throws servletexception, ioexception {

        this.dopost(request, response);
    }

    public void dopost(httpservletrequest request, httpservletresponse response)
            throws servletexception, ioexception {
        string path = d:/upload/哈哈哈.txt;
        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(gb2312),iso8859-1));
            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();
        }
    }

    public void init() throws servletexception {
        // put your code here
    }

}