JAVA基础篇—文件上传下载

时间：2023-03-10 01:08:03
JAVA基础篇—文件上传下载

/index.jsp

<%@ 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>

<script type="text/javascript" src="/web-ajax/js/jquery.min.js"></script>

</head>

<body>

  <form action="${pageContext.request.contextPath}/FileServlet" enctype="multipart/form-data" method="post">

   用户： <input type="text" name="username"/><br>

      <input type="file" name="photo"/><br>

      <input type="file" name="photo1"/><br>

      <input type="file" name="photo2"/><br>

      <input type="submit" value="起飞"/>

  </form>

</body>

</html>

/downlode.jsp

<%@ 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>

  <a href="${pageContext.request.contextPath}/DownServlet">下载吧</a>

</body>

</html>

/class FileServlet

package com.neuedu.servlet;

import java.io.File;

import java.io.IOException;

import java.util.List;

import java.util.UUID;

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.FileItem;

import org.apache.commons.fileupload.FileUploadBase.FileSizeLimitExceededException;

import org.apache.commons.fileupload.FileUploadBase.SizeLimitExceededException;

import org.apache.commons.fileupload.disk.DiskFileItemFactory;

import org.apache.commons.fileupload.servlet.ServletFileUpload;

@WebServlet("/FileServlet")

public class FileServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		//工厂类，用于构建一个解析器实例。

		DiskFileItemFactory factory=new DiskFileItemFactory();

		//创建对象，完成上传

		ServletFileUpload fileupload=new ServletFileUpload(factory);

		fileupload.setSizeMax(1024*1500);

		ServletContext servletContext = request.getServletContext();

		String realPath = servletContext.getRealPath("/upload");

		File file=new File(realPath);

		if (!file.exists()) {

			file.mkdir();

		}

		try {

			List<FileItem>filelist=fileupload.parseRequest(request);

			for (FileItem fileItem : filelist) {

				if (fileItem.isFormField()) {

					String name = fileItem.getFieldName();

					String value = fileItem.getString("utf8");

					System.out.println(name+":"+value);

				}else {

					long size = fileItem.getSize();

					if(size ==0){

						continue;

					}

					String contentType = fileItem.getContentType();

					String name = fileItem.getName();

					if(name.contains("\\")){

						name = name.substring(name.lastIndexOf("\\")+1);

					}

					//uuid_name.jpg

					String prefix = UUID.randomUUID().toString();

					prefix = prefix.replace("-","");

					String fileName = prefix+"_"+name;

//					String fieldName = fileItem.getFieldName();

					System.out.println(size+":"+contentType+":--------"+name+":"+fileName);

					fileItem.write(new File(realPath+"\\"+fileName));

				}

			}

		}catch(FileSizeLimitExceededException e){

			System.out.println("文件大小不可以超过500K");

		}catch(SizeLimitExceededException e){

			System.out.println("总大小不可以超过1500k");

		}  catch (Exception e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		}

	}

}

　　/class DownServlet

package com.neuedu.servlet;

import java.io.File;

import java.io.FileInputStream;

import java.io.IOException;

import java.io.InputStream;

import java.io.PrintWriter;

import javax.servlet.ServletContext;

import javax.servlet.ServletException;

import javax.servlet.ServletOutputStream;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import org.apache.commons.io.IOUtils;

@WebServlet("/DownServlet")

public class DownServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		ServletContext servletContext = request.getServletContext();

		String fileName="风吹麦浪.mp3";

		String path = servletContext.getRealPath("/风吹麦浪.mp3");

		File file=new File(path);

		String type = servletContext.getMimeType(path);

		InputStream in=new FileInputStream(file);

		response.setContentType(type);

		fileName = new String(fileName.getBytes("gbk"),"iso8859-1");

		response.setHeader("Content-Disposition", "attachment; filename="+fileName);

		ServletOutputStream out=response.getOutputStream();

		IOUtils.copy(in, out);

		in.close();

	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		doGet(request, response);

	}

}

　　JAVA基础篇—文件上传下载

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