文件上传

最新推荐文章于 2024-08-02 16:51:08 发布

原创最新推荐文章于 2024-08-02 16:51:08 发布 · 305 阅读

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1、首先导入：commons-fileupload-1.3.3.jar和commons-io-2.5.jar

2、创建upload.jsp页面

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
   
   <form action="<%=request.getContextPath() %>/upload" method="post" enctype="multipart/form-data">
       用户名：<input type="text" name="username"/><br/>
       <input type="file" name="myfile"/><br/>
       <input type="submit" value="上传"/>
   </form>
</body>

</html>

3、servlet

package com.hx.shopping.web;

import java.awt.SystemColor;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
import java.text.SimpleDateFormat;
import java.util.stream.Stream;

import javax.servlet.ServletContext;
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 org.apache.commons.fileupload.FileItemIterator;
import org.apache.commons.fileupload.FileItemStream;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.fileupload.util.Streams;
import org.apache.commons.io.FileUtils;

@WebServlet("/upload")
public class LoadServlet extends HttpServlet{

   private static final long serialVersionUID = 1L;

   @Override
   protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       doPost(req, resp);
   }

   @Override
   protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       //当表单上传类型改为二进制类型时，此方法不再能接收传过来的字段    String username = req.getParameter("username");

       //判断是否是文件请求
       boolean isMultipart = ServletFileUpload.isMultipartContent(req);
       try {
           if(isMultipart){
               //创建一个新的文件上传处理器
               ServletFileUpload upload = new ServletFileUpload();
               //产生一个迭代器
               FileItemIterator iter = upload.getItemIterator(req);
               while(iter.hasNext()){
                   //传过来的是多个文本域的流，FileItemStream：获得单个文本域的流
                   FileItemStream item = iter.next();//FileInputStream 用于读取诸如图像数据之类的原始字节流。要读取字符流，请考虑使用 FileReader。
                   //获取字段名字：username、myfile
                   String name = item.getFieldName();
                   //打开流，打开才能使用
                   InputStream istream = item.openStream();
                   //判断是否是普通的表单字段
                   if(item.isFormField()){
                       //Streams.asString(istream):将流转换成字符串
                       System.out.println("form filed:"+name+",value:"+Streams.asString(istream));
                   }else{
                       //getServletContext()：获得一个ServletContext对象（一个全局的储存信息的空间，服务器开始就存在，服务器关闭才释放。所有用户共用一个）   getContextPath():获取跟路径/Shopping4
                       String filePath = req.getSession().getServletContext().getRealPath("/upload");//eclipse临时文件路径：E:\Lay\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\Shopping4\ upload
                       //拼接上文件名
                       String tail = item.getName().substring(item.getName().indexOf("."));
                       //使用时间戳来为上传的文件命名，避免不可重复上传的问题
                       SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddhhmmssSSS");//SSS具体到毫秒数
                       String timeName = sdf.format(new Date());
                       filePath += "/"+timeName+tail;
                       //将流拷贝到文件中去
                       FileUtils.copyInputStreamToFile(istream, new File(filePath));// new File(filePath):自动创建文件夹
                   }
               }
           }
       } catch (Exception e) {
           e.printStackTrace();
       }
   }
}