文件上传

上传对表单和Servlet的限制

上传不能使用BaseServlet

多部件表单的体

commons-fileupload组件介绍

测试：

package cn.cmlx.web.servlet;

import java.io.File;
import java.io.IOException;
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.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

@WebServlet("/Upload1Servlet")
public class Upload1Servlet extends HttpServlet {

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");

        /*
         * 上传三步 1.得到工厂 2.通过工厂创建解析器 3.解析request，得到FileItem集合 4.遍历FileItem集合，调用其API完成文件的保存
         */
        DiskFileItemFactory factory = new DiskFileItemFactory();
        ServletFileUpload sfu = new ServletFileUpload(factory);
        try {
            List<FileItem> fileItemList = sfu.parseRequest(request);
            FileItem fi1 = fileItemList.get(0);
            FileItem fi2 = fileItemList.get(1);

            System.out.println("普通表单项演示：" + fi1.getFieldName() + "=" + fi1.getString("utf-8"));
            System.out.println("文件表单项演示");
            System.out.println("Content-Type:" + fi2.getContentType());
            System.out.println("size" + fi2.getSize());
            System.out.println("filename" + fi2.getName());
            // 保存文件
            File destFile = new File("c:/huyao.jpg");
            fi2.write(destFile);
        } catch (FileUploadException e) {
            throw new RuntimeException(e);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

}
测试

 上传的代码演示

form1.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!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>
    <h1>上传</h1>
    <form action="<c:url value='/Upload1Servlet'/>" method="post"
        enctype="multipart/form-data">
        用户名：<input type="text" name="username" /><br /> 照　片：<input
            type="file" name="zhaoPian" /><br /> <input type="submit"
            value="上传" />
    </form>
</body>
</html>
form1.jsp

Upload1Servlet.java

package cn.cmlx.web.servlet;

import java.io.File;
import java.io.IOException;
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.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

@WebServlet("/Upload1Servlet")
public class Upload1Servlet extends HttpServlet {

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");

        /*
         * 上传三步 1.得到工厂 2.通过工厂创建解析器 3.解析request，得到FileItem集合 4.遍历FileItem集合，调用其API完成文件的保存
         */
        DiskFileItemFactory factory = new DiskFileItemFactory();
        ServletFileUpload sfu = new ServletFileUpload(factory);
        try {
            List<FileItem> fileItemList = sfu.parseRequest(request);
            FileItem fi1 = fileItemList.get(0);
            FileItem fi2 = fileItemList.get(1);

            System.out.println("普通表单项演示：" + fi1.getFieldName() + "=" + fi1.getString("utf-8"));
            System.out.println("文件表单项演示");
            System.out.println("Content-Type:" + fi2.getContentType());
            System.out.println("size" + fi2.getSize());
            System.out.println("filename" + fi2.getName());
            // 保存文件
            File destFile = new File("F:/huyao.jpg");
            fi2.write(destFile);
        } catch (FileUploadException e) {
            throw new RuntimeException(e);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

}
UploadServlet.java

上传的细节

案例：

Upload2Servlet.java

package cn.cmlx.web.servlet;

import java.io.File;
import java.io.IOException;
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.FileUploadBase;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

import cn.itcast.commons.CommonUtils;

@WebServlet("/Upload2Servlet")
public class Upload2Servlet extends HttpServlet {

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        // 上传三步
        // 获取工厂
        DiskFileItemFactory factory = new DiskFileItemFactory(20*1024,new File("F:/F/temp"));
        // 获取解析器
        ServletFileUpload fileUpload = new ServletFileUpload(factory);
        // fileUpload.setFileSizeMax(100 * 1024);// 限制单个文件大小为100k
        // fileUpload.setSizeMax(1024 * 1024);// 限制整个表单大小为1M
        // 解析得到List
        try {
            List<FileItem> list = fileUpload.parseRequest(request);
            FileItem f1 = list.get(1);
            ////////////////////////////////////////
            /*
             * 1.得到文件保存的路径
             */
            String root = this.getServletContext().getRealPath("/WEB-INF/files/");
            /*
             * 2.生成二层目录 1.得到文件名称 2.得到hashCode 3.转发成16进制 4.获取前两个字符用来生成目录
             */
            String filename = f1.getName();// 获取上传的文件名
            /*
             * 处理文件名的绝对路径问题
             */
            int index = filename.lastIndexOf("\\");
            if (index != -1) {
                filename = filename.substring(index + 1);
            }
            /*
             * 给文件名称添加uuid前缀，处理文件同名问题
             */
            String save = CommonUtils.uuid() + "_" + filename;
            /*
             * 1.得到hashCode
             */
            int hCode = filename.hashCode();
            String hex = Integer.toHexString(hCode);// 转为16进制
            /*
             * 2.获取hex的前两个字母，与root连接在一起，生成一个完整的路径
             */
            File dirFile = new File(root, hex.charAt(0) + "/" + hex.charAt(1));
            /*
             * 3.创建目录链
             */
            dirFile.mkdirs();
            /*
             * 4.创建目录文件
             */
            File destFile = new File(dirFile, save);
            /*
             * 5.保存
             */
            f1.write(destFile);
        } catch (FileUploadException e) {
            if (e instanceof FileUploadBase.FileSizeLimitExceededException) {
                request.setAttribute("msg", "您上传的文件超出了100kb！");
                request.getRequestDispatcher("/form2.jsp").forward(request, response);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
Upload2Servlet.java

 

posted @ 2018-09-01 13:22  cmlx  阅读(116)  评论(0)    收藏  举报