限制上传大小、用COS实现文件上传与下载 五（63）

一 限制上传大小

1：限制总文件的大小 。    如 上传10文件，设置最多总上传大小为100M。

void	setSizeMax(long sizeMax)           Sets the maximum allowed size of a complete request, as opposed to setFileSizeMax(long).

2：设置第每一个文件的大小 ，如果设置每 一个文件大小10M。

 

void	setFileSizeMax(long fileSizeMax)           Sets the maximum allowed size of a single uploaded file, as opposed to getSizeMax().

 二 用COS实现文件上传

 

package cn.hx;

import java.io.File;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.UUID;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.oreilly.servlet.MultipartRequest;

import com.oreilly.servlet.multipart.DefaultFileRenamePolicy;

import com.oreilly.servlet.multipart.FileRenamePolicy;

/**

 * 在Cos中就一个类，

 * MultipartRequest它是request的包装类。

 */

public class CosServlet extends HttpServlet {

 public void doPost(HttpServletRequest request, HttpServletResponse resp)

throws ServletException, IOException {



       //第一步：声明文件的保存目录



       String path = getServletContext().getRealPath("/up");



       //第二步：文件传



       //声明文件重新取名的策略



       FileRenamePolicy rename = new DefaultFileRenamePolicy();



       MultipartRequest req =



              new MultipartRequest(request,path,1024*1024*100,"UTF-8",new MyRename());



//     //第三步：显示信息，



       resp.setContentType("text/html;charset=UTf-8");



       PrintWriter out = resp.getWriter();



       out.print("文件名称1:"+req.getOriginalFileName("img1"));



       out.print("<br/>新名称:"+req.getFilesystemName("img1"));



       out.print("<br/>类型1:"+req.getContentType("img1"));



       out.print("<br/>大小1："+req.getFile("img1").length());



       out.print("<br/>说明:"+req.getParameter("desc1"));



       if(req.getContentType("img1").contains("image/")){



           out.print("<img src='"+request.getContextPath()+"/up/"+req.getFilesystemName("img1")+"'></img>");



       }



    }



}



class MyRename implements FileRenamePolicy{



    public File rename(File file) {



       String fileName = file.getName();



       String extName = fileName.substring(fileName.lastIndexOf("."));



       String uuid = UUID.randomUUID().toString().replace("-","");



       String newName = uuid+extName;//abc.jpg



       file = new File(file.getParent(),newName);



       return file;



    }



}

三 下载

即可是get也可以是post。

    public void doPost(HttpServletRequest req, HttpServletResponse resp)

           throws ServletException, IOException {

       req.setCharacterEncoding("UTF-8");

       String name = req.getParameter("name");

       //第一步：设置响应的类型

        resp.setContentType("application/force-download");

       //第二读取文件

       String path = getServletContext().getRealPath("/up/"+name);

       InputStream in = new FileInputStream(path);

       //设置响应头

       //对文件名进行url编码

       name = URLEncoder.encode(name, "UTF-8");

       resp.setHeader("Content-Disposition","attachment;filename="+name);

       resp.setContentLength(in.available());

       //第三步：开始文件copy

       OutputStream out = resp.getOutputStream();

       byte[] b = new byte[1024];

       int len = 0;

       while((len=in.read(b))!=-1){

           out.write(b,0,len);

       }

       out.close();

       in.close();

    }