servlet实现简易的文件上传与下载_网页代码上传下载简易-优快云博客

记录一些学习心得，servlet实现一个简易的文件上传与下载，话不多说，直接上代码；
首先是前端页面：

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>


<form method="POST" action="upload" enctype="multipart/form-data">

	用    户：<input type="text" name="userName"/><br/>
	照    片：<input type="file" name="myImg"/><br/>
	
	密    码：<input type="text" name="passWord"/>
	<input type="submit" value="提交"/><br/>
	
</form>

<form method="GET" action="down" enctype="multipart/form-data">
	<a href="down">下载</a>

</form>


</body>
</html>

界面效果图如下：
在这里插入图片描述
第二是上传文件部分：

package com.Loading;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
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.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.tomcat.util.http.fileupload.IOUtils;

@WebServlet(urlPatterns ="/upload")

public class UploadServler extends HttpServlet {

	//在本地盘创建新文件夹
	static final String savePath = "E:\\onload\\";
	
	@Override
	protected void doPost( HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		//在控制台输出用户名和密码（可以不输出）
		/*String userName = req.getParameter("userName");
		resp.getWriter().println(userName);
		String password = req.getParameter("passWord");
		resp.getWriter().println(password);*/
		
		 //处理Multipart编码格式的数据
		 boolean isMultipart = ServletFileUpload.isMultipartContent(req);
		 
		 if(isMultipart) {
			 
			//为基于磁盘的文件项创建工厂
			 DiskFileItemFactory factory = new DiskFileItemFactory();

			 //创建一个新的文件上传处理程序
			 ServletFileUpload uploader = new ServletFileUpload(factory);

			 //解决了中文乱码
			 uploader.setHeaderEncoding("UTF-8");
			 //解析请求
			
			try {
				 List<FileItem> items = uploader.parseRequest(req);
				
				for (FileItem fileItem : items) {
					if(fileItem.isFormField()) {
						String name = fileItem.getFieldName();//文本框名称
						String value = fileItem.getString();//文本框的值
						System.out.println(name+"-----"+value);
						
					}else {
						//文件
						String fieldName = fileItem.getFieldName();
						//文件名
						String fileName = fileItem.getName();
		
						System.out.println("文件："+fieldName +"----"+fileName);
						
						InputStream inputStream = fileItem.getInputStream();
						String fileDest = savePath + fileName;
						FileOutputStream outputStream = new FileOutputStream(fileDest);
					
						IOUtils.copy(inputStream ,outputStream); 
						
						inputStream.close();
						outputStream.close();
						
					}
				}
	
				
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
				 
		 }
		 	
	}
  
}

最后一部分就是下载文件：

package com.Loading;

import java.io.FileInputStream;
import java.io.IOException;
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.io.IOUtils;

@WebServlet(urlPatterns="/down")

public class Download extends HttpServlet{

//保存下载文件的文件夹路径
static final String savePath="E:\\onload\\";

/**
 * 在资源文件夹里面下载文件
 */
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
	//要下载的文件（这里写死了，没加选择资源的功能）
	String fileName="7712.jpg";
	
	resp.setContentType("text/plain");
	resp.setHeader("Location", fileName);
	resp.setHeader("Content-Disposition", "attachment;filename="+fileName);
	
	//文件输出流保存到到文件夹
	FileInputStream fis=new FileInputStream(savePath+fileName);
	IOUtils.copy(fis, resp.getOutputStream());
}

}
光阴似箭，日月如梭，小白一枚，不喜勿喷，望与君共勉！