是什么
上传指的是将客户端的文件保存到服务器的磁盘中
基本实现原理
读取客户端的文件信息,将文件信息以流的形式发送到服务器,然后服务器将流中的信息保存到本地,以实现文件的上传
实例
注意:提交的表单类型一定是 enctype="multipart/form-data"
<%@ 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="fileUploadServlet"method="post" enctype="multipart/form-data">上传文件:<input type="file" name="file1"><input type="file" name="file2"><input type="file" name="file3"><br><input type="submit" value="上传"></form>
</body>
</html>
import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Collection;import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;//配置servlet,并且支持上传文件
@WebServlet(name="fileUploadServlet" ,urlPatterns="/fileUploadServlet")
@MultipartConfig
public class FileUploadServlet extends HttpServlet {private static final long serialVersionUID = 1L;@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {System.out.println("到这里来了");doGet(request, response);}@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {//1、字符编码格式统一request.setCharacterEncoding("utf-8");response.setCharacterEncoding("utf-8");response.setContentType("text/html;charset=utf-8");//2、设置一个保存文件的路径String savePath = "F:/czp/";//3、获取上传的文件集合Collection<Part> parts = request.getParts();//4、文件上传if (parts != null && parts.size() > 0) {for (Part part : parts) {String header = part.getHeader("content-disposition");String fileName = getFileName(header);part.write(savePath + File.separator + fileName);}}PrintWriter out = response.getWriter();out.println("上传成功");out.flush();out.close();}/*** 获取文件名* @param header* @return*/public String getFileName(String header) {String[] headerArray = header.split(";");System.out.println(headerArray[2]);String[] fileNameKeyValue = headerArray[2].split("=");String fileName = fileNameKeyValue[1].substring(fileNameKeyValue[1].lastIndexOf("\\") + 1).replaceAll("\"", "");return fileName;}
}