文件上传的步骤

文件上传的步骤:
1.
2.首先要更改form的enctype="multipart/form-data"
表示向服务器传输的过程中以二进制的方式传输
默认传输类型: enctype="application/x-www-form-urlencoded"
3.相关jar包 下载地址 www.apache.org
commons-fileupload-1.2.1.jar 核心组件包
commons-io-2.0.1.jar --fileupload组件包,依赖了IO
commons-lang3-3.1.jar
commons-logging-1.1.3.jar

json-lib-2.4-jdk15.jar JSON工具类
struts2-json-plugin-2.3.15.1.jar

4.普通上传页面

`<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<html> <head> <title>文件上传的开发</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> </head>

`

5.ajax上传页面

`<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>


ajax文件上传的开发



</head>
文件上传






`

6.后台处理类

`<%@page import="org.apache.struts2.json.JSONUtil"%>
<%@page import="com.rui.util.StrUtils"%>
<%@page import="java.io.File"%>
<%@page import="org.apache.commons.fileupload.FileItem"%>
<%@page import="org.apache.commons.fileupload.servlet.ServletFileUpload"%>
<%@page import="org.apache.commons.fileupload.disk.DiskFileItemFactory"%>
<%@page import="org.apache.commons.fileupload.FileItemFactory"%>
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%

/文件上传的方式/

//1.获取文件上传的工厂类
FileItemFactory factory = new DiskFileItemFactory();
//2.解析上传文件的工厂
ServletFileUpload fileUpload = new ServletFileUpload(factory);
//3.通过解析类解析request对象中的二进制文件
List fileItems = fileUpload.parseRequest(request);
//4.读取二进制文件,写入服务器

//获取服务器的路径getRealPath()获取当前项目所在服务器的根目录
//D:\tool\dev\apache-tomcat-7.0.56-windows-x86\apache-tomcat-7.0.56\me-webapps\fileUpload\resource
String dirpath = request.getParameter("dirpath");//
if(StrUtils.isEmpty(dirpath)) dirpath = "default";
String fpath = "resource/"+dirpath;
String path = request.getRealPath(fpath);
File rootPath = new File(path);
//如果目录不存在就动态创建
if(!rootPath.exists()){
rootPath.mkdirs();
}

//如果有文件,就开始进行读和写
if(fileItems != null && fileItems.size()>0){
List<Map<String,Object>> maps = new ArrayList<Map<String,Object>>();
for(FileItem fileItem : fileItems){
if(!fileItem.isFormField()){//判断是不是file表单
//获取文件名称
String filename = fileItem.getName();
//文件大小
long filesize = fileItem.getSize();
//获取文件后缀
String ext = StrUtils.getExt(filename, true);
//重构文件的名称===头像上传的原理就是文件的覆盖
String fname = UUID.randomUUID().toString()+ext;
File fileName = new File(rootPath,fname);
fileItem.write(fileName);

Map<String,Object> map = new HashMap<String,Object>();
map.put("name", filename);
map.put("size", filesize);
map.put("sizeString", StrUtils.countFileSize(filesize));
map.put("url", fpath+"/"+fname);
maps.add(map);

}
}
out.print(JSONUtil.serialize(maps));
}else {
out.print("");
//response.sendRedirect("fail.jsp");
}
//5.在服务器创建一个上传的目录
//6.开始写入
//7.返回数据

//response.sendRedirect("success.jsp");

%>`

7.工具类

`package com.rui.util;

import java.text.DateFormat;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Random;

/**
*

  • @ClassName: StrUtils

  • @Description: 工具类

  • @author poseidon

  • @date 2015年10月23日 下午8:13:45

  • @version V1.0.0
    */
    public class StrUtils {

    /**
    *

    • @Title: isEmpty
    • @Description: 空判断
    • @param content
    • @return boolean
      */
      public static boolean isEmpty(String content){
      return (content==null || content.equals(""))?true:false;
      }

    /**
    *

    • @Title: isNotEmpty
    • @Description: 非空判断
    • @param content
    • @return boolean
      */
      public static boolean isNotEmpty(String content){
      return !isEmpty(content);
      }

    /**
    *

    • @Title: formatDate
    • @Description: 格式化日期类
    • @param date
    • @param pattern
    • @return String
      */
      public static String formatDate(Date date,String pattern){
      if(date!=null){
      String dateString = new SimpleDateFormat(pattern).format(date);
      return dateString;
      }else{
      return "";
      }
      }

    /**
    *

    • @Title: getExt
    • @Description: 获取文件的后缀
    • @param name 文件名称
    • @param flag true有点false没点
    • @return String
      */
      public static String getExt(String name,boolean flag){
      if(isNotEmpty(name)){
      String ext = null;
      if(flag){
      ext = name.substring(name.lastIndexOf("."), name.length());
      }else{
      ext = name.substring(name.lastIndexOf(".")+1, name.length());
      }
      return ext;
      }else{
      return "";
      }
      }

    /**
    *

    • @Title: generateFileName
    • @Description: 为上传文件自动分配文件名称，避免重复
    • @param fileName
    • @param randomNum
    • @param dataPattern
    • @return String
      */
      public static String generateFileName(String fileName,int randomNum,String dataPattern) {
      // 获得当前时间
      DateFormat format = new SimpleDateFormat(dataPattern);
      // 转换为字符串
      String formatDate = format.format(new Date());
      // 随机生成文件编号
      int random = new Random().nextInt(randomNum);
      // 获得文件后缀名称
      int position = fileName.lastIndexOf(".");
      String extension = fileName.substring(position);
      // 组成一个新的文件名称
      return formatDate + random + extension;
      }

    /**
    *

    • @Title: countFileSize
    • @Description: 根据File文件的长度统计文件的大小
    • @param fileSize
    • @return String
      */
      public static String countFileSize(long fileSize) {
      String fileSizeString = "";
      try {
      DecimalFormat df = new DecimalFormat("#.00");
      long fileS = fileSize;
      if (fileS == 0) {
      fileSizeString = "0KB";
      } else if (fileS < 1024) {
      fileSizeString = df.format((double) fileS) + "B";
      } else if (fileS < 1048576) {
      fileSizeString = df.format((double) fileS / 1024) + "KB";
      } else if (fileS < 1073741824) {
      fileSizeString = df
      .format(((double) fileS / 1024 / 1024) - 0.01)
      + "MB";
      } else {
      fileSizeString = df.format((double) fileS / 1024 / 1024 / 1024)
      + "G";
      }
      } catch (Exception e) {
      e.printStackTrace();
      }
      return fileSizeString;
      }

    /**
    *

    • @Title: conversionSpecialCharacters
    • @Description: 把两个反斜线转换成正斜线
    • @param string
    • @return String
      */
      public static String conversionSpecialCharacters(String string) {
      return string.replaceAll("\\", "/");
      }

    public static void main(String[] args) {

    }
    }`

https://www.cnblogs.com/sun-rain/p/5203180.html

posted @ 2021-02-25 11:11  画画的Baby~  阅读(204)  评论(0)    收藏  举报