37、JAVA_WEB开发基础之上传功能

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;

	@Override
	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		System.out.println("到这里来了");
		doGet(request, response);
	}

	@Override
	protected 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;
	}
}

37、JAVA_WEB开发基础之上传功能

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