用COS实现文件上传

cos是O'Rrilly公司开发的一款用于HTTP上传文件的OpenSource组件

需要cos.jar,下载地址：http://www.servlets.com/cos/

cos上传文件很简单，比fileupload还简单：但是上传最大我试了试，是800多兆，超过直接崩溃：

java.io.IOException: Posted content length of 1627105576 exceeds limit of 889192448 --->byte，800多M

只需一个servelt即可：

package com.lhy.upload;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.util.Enumeration;
import java.util.UUID;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
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.FileRenamePolicy;

/**
 * CosServlet
 *  在Cos中就一个类，
 *  MultipartRequest它是request的包装类。
 */
@WebServlet(name="CosServlet",urlPatterns="/CosServlet")
public class CosServlet extends HttpServlet{

  @Override
  protected void doPost(HttpServletRequest req, 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：文件上传
    //声明文件重新命名策略,默认的不行不能重命名，自己实现FileRenamePolicy接口
//    FileRenamePolicy rename = new DefaultFileRenamePolicy();
    MultipartRequest multiReq = new MultipartRequest(req, path, 1024*1024*100, "UTF-8",new MyRename());

    //输出所上传的文件的信息
    Enumeration fileNames = multiReq.getFileNames();
    while(fileNames.hasMoreElements()){
        String name  = (String)fileNames.nextElement();
        File file = multiReq.getFile(name);//得到上传的文件
        if(null != file){
            String fileName  = multiReq.getFilesystemName(name);   //取得文件名
            String contentType = multiReq.getContentType(name);//类型
            System.out.println("上传的文件: " +fileName+"，  文件类型: "+contentType);
        }
    }  

    //输出所提交的表单中其它文本输入域的值
    Enumeration formValue = multiReq.getParameterNames();
    while(formValue.hasMoreElements()){
        String param = (String)formValue.nextElement();
        String value = multiReq.getParameter(param);
        System.out.println(value);
    } 

    //第三步：如果知道input的name，还可以直接获取信息，
    /*resp.setContentType("text/html;charset=UTf-8");
    PrintWriter out = resp.getWriter();
    out.print("文件名称1:"+multiReq.getOriginalFileName("img1"));
    out.print("<br/>新名称:"+multiReq.getFilesystemName("img1"));
    out.print("<br/>类型1:"+multiReq.getContentType("img1"));
    out.print("<br/>大小1："+multiReq.getFile("img1").length());
    out.print("<br/>说明:"+multiReq.getParameter("desc1"));
    if(multiReq.getContentType("img1").contains("image/")){
      out.print("<img width='300px' height='200px' src='"+req.getContextPath()+"/up/"+multiReq.getFilesystemName("img1")+"'></img>");
    }

  out.print("<hr/>");
  out.print("文件名称2:"+multiReq.getOriginalFileName("img2"));
  out.print("<br/>类型2:"+multiReq.getContentType("img2"));
  out.print("<br/>大小2："+multiReq.getFile("img2").length());
  out.print("<br/>说明2:"+multiReq.getParameter("desc2"));

//
  out.print("<hr/>");
  out.print("文件名称3:"+multiReq.getOriginalFileName("img3"));
  out.print("<br/>类型3:"+multiReq.getContentType("img3"));
  out.print("<br/>大小3："+multiReq.getFile("img3").length());
  out.print("<br/>说明3:"+multiReq.getParameter("desc3"));*/

  }

}

/**
 * 重命名策略，
 */
class MyRename implements FileRenamePolicy{

  @Override
  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;
  }

}

表单：

<form action="<c:url value='/CosServlet'/>" method="post"
        enctype="multipart/form-data">
        File1：<input type="file" name="img1"><br /> 说明1：
        <input type="text" name="desc1"><br />

        File2：<input type="file" name="img2"><br/>
        说明2：<input type="text" name="desc2"><br/>
        File3：<input type="file" name="img3"><br/>
        说明3：<input type="text" name="desc3"><br/>

        <input type="submit" />
    </form>

启动上传：

服务端：

还是很给力的。