• 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。

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  • 原文地址:https://www.cnblogs.com/lihaoyang/p/7346495.html
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