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"%>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>ajax文件上传的开发</title>
<meta name="keywords" content="" />
<meta name="description" content="" />
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<style type="text/css">
#percent{width:600px;height:30px;position:relative;border:1px solid green;}
#percent #per{height:30px;background:green;position:absolute;left:0;top:0;}
</style>
<img id="showImg" width="160" height="120" />
<ul id="showlist">
</ul>
<div id="percent">
<div id="per"></div>
</div>
<div id="pnum"></div>
<script type="text/javascript">
function openFileDialog(){
var ie = navigator.appName == "Microsoft Internet Explorer"?true:false;
if(ie){
//如果是ie浏览器
document.getElementById("file").click();
}else{
//自定义事件es5中的内容
var a = document.createEvent("MouseEvents");
a.initEvent("click",true,true);
document.getElementById("file").dispatchEvent(a);
}
};
//ajax文件上传 不支持低版本浏览器
function uploadFile(){
//拿到文件上传的队列
var files = document.getElementById("file").files
var file = files[0];
var type = file.type;//文件类型
var name = file.name;//文件名称
var size = file.size;//文件大小
if(type.indexOf("image") == -1) {
alert("请上传图片类型")
return;
}
//alert(file.name+"===="+file.size+"==="+file.type);
showImage(file,function(data){
document.getElementById("showImg").src=data;
})
var form = new FormData();
form.append("file",file);
//如何传输给服务器端，进度条
var xhr = new XMLHttpRequest();
//请求服务器
xhr.open("post", "upload/uploadAction.jsp?dirpath=pipi",true);
xhr.onreadystatechange = function(){
if(this.readyState == 4 && this.status == 200){
var data = this.responseText;
var jsonData = eval("("+data+")");
var html = "";
for(var i=0;i<jsonData.length;i++){
html += "<li>"+jsonData[i].name+"===="+jsonData[i].sizeString+"====<img src='"+jsonData[i].url+"' width='50' height='50'/>"
}
console.log(data);
document.getElementById("showlist").innerHTML += html;
}
};
xhr.upload.addEventListener("progress", progressFunction,false);
xhr.send(form);
}
//进度条
function progressFunction(evt){
console.log("------");
var perDom = document.getElementById("per");
if(evt.lengthComputable){
//evt.loaded已经上传了多少
//event.total上传文件的总大小
var p = evt.loaded / event.total;
console.log(p);
var pnum = Math.floor(p*100) +"%";
perDom.style.width = pnum;
document.getElementById("pnum").innerHTML = pnum;
}
}
/*图片预览*/
function showImage(f,callback){
var reader = new FileReader();
reader.onload = (function(theFile) {
return function(e) {
// img 元素
if(callback)callback(e.target.result);
};
})(f);
reader.readAsDataURL(f);
};
</script>
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<FileItem> 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) {
}
}`
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