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表单method="post" entype="multipart/from-data"
表单中需要提交文件表单项 必须要有name属性
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Servlet
当enctype="multipart/from-data" 使用 getparmeter方法就不能用了
适用 servletInputStream request.getInputStream();包含整个请求体。
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上传的细节问题：
文件必须保存在web-inf下！
????目的是不让浏览器直接访问到
文件名相关的问题
????有的浏览器上传的文件名是绝对路径，这需要切割！c:\files\baibing.jpg
String filename=fi2.getname();
Int index=filename.lastIndexOf("\\");
If(index!=-1){
????Filename=filename.substring(index+1);
}
????文件名乱码或者普通表单项乱码
Request.setCharsetEncoding("utf-8");
servletFileUpload.setHeaderEncoding("utf-8");
????文件同名问题 我们需要为每个文件设置一个uuid
Filename=commonUtils.uuid()+"_"+filename;
目录打散
????不能在一个目录下存放之多个文件
上传文件的大小限制
????单个文件大小限制
Sfu.setFileSizeMax(100*1024)//限制文件大小为100k
//必须要在获取解析之前执行
Sfu.setsizemax(1024*1024);//超出是抛出异常
????整个请求所有数据大小限制
缓存大小与临时目录
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package com.pcx.servlet; ? import java.io.File; import java.io.IOException; import java.util.List; ? import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; ? import org.apache.commons.fileupload.FileItem; import org.apache.commons.fileupload.FileUploadException; import org.apache.commons.fileupload.disk.DiskFileItemFactory; import org.apache.commons.fileupload.servlet.ServletFileUpload; ? public class Upload2Servlet extends HttpServlet { ? ????public void doGet(HttpServletRequest request, HttpServletResponse response) ????????????throws ServletException, IOException { ? ????} ? ????public void doPost(HttpServletRequest request, HttpServletResponse response) ????????????throws ServletException, IOException { ????????request.setCharacterEncoding("utf-8"); ????????response.setContentType("text/html;charset=utf-8"); ????????DiskFileItemFactory factory=new DiskFileItemFactory(); ????????ServletFileUpload sfu=new ServletFileUpload(factory); ???????? ????????try { ????????????List<FileItem>fileItemlist=sfu.parseRequest(request); ????????????FileItem fi1=fileItemlist.get(0); ????????????FileItem fi2=fileItemlist.get(1); ????????????System.out.println("普通表单项演示"+fi1.getFieldName()+"=="+fi1.getString("UTF-8")); ????????????System.out.println("文件表单项获取："); ????????????System.out.println("Content-type:"+fi2.getContentType()); ????????????System.out.println("size"+fi2.getSize()); ????????????System.out.println("filename"+fi2.getName()); ???????????? ????????????File desc=new File("D:/linghucong.jpg");//一般保存在web-Inf ????????????fi2.write(desc); ????????} catch (FileUploadException e) { ????????????e.printStackTrace(); ????????} catch (Exception e) { ????????????// TODO Auto-generated catch block ????????????e.printStackTrace(); ????????} ????} ? ? ? </head> ? <body> This is my JSP page. <br> <form action="<c:url value=‘/Upload2Servlet‘/>" method="post" enctype="multipart/form-data"> 用户名<input type="text" name="username"> 照片<input type="file" name="zhaopian"> <input type="submit" value="提交"/> </form> </body> </html> |
? public class Upload3Servlet extends HttpServlet { ? ????public void doGet(HttpServletRequest request, HttpServletResponse response) ????????????throws ServletException, IOException { ? ????} ? ????public void doPost(HttpServletRequest request, HttpServletResponse response) ????????????throws ServletException, IOException { ????????request.setCharacterEncoding("utf-8"); ????????response.setContentType("text/html;charset=utf-8"); ????????//工厂 ????????DiskFileItemFactory factory=new DiskFileItemFactory(); ????????//解析器 ????????ServletFileUpload sfu=new ServletFileUpload(factory); ????????try { ????????????List<FileItem>list=sfu.parseRequest(request); ????????????FileItem fi1=list.get(1); ???????????? ????????????//拿到文件的根路径 ????????????String root=this.getServletContext().getRealPath("/WEB-INF/files/"); ????????????//得到文件名 处理绝对路径问题 得到hashCode值 转为16进制 使用前两个字符生成目录 ???????????? ????????????String filename=fi1.getName(); ????????????int index=filename.indexOf("\\"); ????????????if(index!=-1){ ????????????????filename=filename.substring(index+1); ????????????} ???????????? ????????????//添加文件的前缀问题 ????????????String savename=CommonUtils.uuid()+"_"+filename; ???????????? ????????????//得到hashcode值 ????????????int hcode=filename.hashCode(); ????????????String hex=Integer.toHexString(hcode); ???????????? ????????????//生成对应的两层结构 ????????????File dirFile=new File(root,hex.charAt(0)+"/"+hex.charAt(1)); ????????????//创建目录连 ????????????dirFile.mkdirs(); ???????????? ????????????//创建目标文件 ????????????File dest=new File(dirFile,savename); ???????????? ????????????//保存 ????????????fi1.write(dest); ????????} catch (FileUploadException e) { ????????????e.printStackTrace(); ????????} catch (Exception e) { ????????????e.printStackTrace(); ????????} ????} ? } |
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????fi1.write(dest); ????????} catch (FileUploadException e) { ????????????if( e instanceof FileUploadBase.FileSizeLimitExceededException){ ????????????????request.setAttribute("msg","你上传的文件超过100k！"); ????????????????request.getRequestDispatcher("/form3.jsp").forward(request, response); ????????????} ????????} catch (Exception e) { ????????????e.printStackTrace(); ????????} ? ? <span>${requestScope.msg }</span> |
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向客户端响应字节数据。
Response.getoutputStream
两个头 一个流
Content-type mime类型
Content-disposition 默认inline
文件名乱码 问题
Firefox 使用的是base64编码
大部分的浏览器是url编码
通用方案：filename=new String (filename.getByte("GBK"),"iso-8859-1")
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????public void doGet(HttpServletRequest request, HttpServletResponse response) ????????????throws ServletException, IOException { ????????String filename="D:/令狐冲.jpg"; ????????String framename=new String(filename.getBytes("GBK"),"ISO-8859-1"); ???????? ????????String contenttype=this.getServletContext().getMimeType(filename); ????????String contentDisposition="attchment;filename="+framename; ????????FileInputStream in=new FileInputStream(filename); ????????response.setHeader("Content-Type", contenttype); ????????response.setHeader("Content-Disposition", contentDisposition); ???????? ????????ServletOutputStream out=response.getOutputStream(); ???????? ????????IOUtils.copy(in, out); ????????in.close(); ????} |
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原文地址：http://www.cnblogs.com/chengzhipcx/p/5021518.html
