javaweb实现文件上传示例代码
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2024-03-02 18:34:58
本文实例为大家分享了javaweb文件下载的具体实现代码，供大家参考，具体内容如下
文件上传示例
注意：jsp页面编码为"utf-8"
文件上传的必要条件
1.fo...
本文实例为大家分享了javaweb文件下载的具体实现代码，供大家参考，具体内容如下
文件上传示例
注意：jsp页面编码为"utf-8"
文件上传的必要条件
1.form表单，必须为post方式提交
2.enctype="multipart/form-data"
3.必须有<input type="file" />
前端jsp页面
<%@ page language="java" import="java.util.*" pageencoding="utf-8"%>
<%
string path = request.getcontextpath();
string basepath = request.getscheme()+"://"+request.getservername()+":"+request.getserverport()+path+"/";
%>
<!doctype html public "-//w3c//dtd html 4.01 transitional//en">
<html>
<head>
<base href="<%=basepath%>" rel="external nofollow" >
<title>my jsp 'index.jsp' starting page</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" rel="external nofollow" >
-->
</head>
<script type="text/javascript">
function addfile(){
var div1=document.getelementbyid("div1");
div1.innerhtml+="<div><input type='file' /><input type='button' value='删除' onclick='deletefile(this)' /> <br/></div>";
}
function deletefile(div){
//他的爷爷删除他的爸爸
div.parentnode.parentnode.removechild(div.parentnode);
}
</script>
<body>
<form action="${pagecontext.request.contextpath }/servlet/uploadservlet" method="post" enctype="multipart/form-data">
文件的描述：<input type="text" name ="description" /><br/>
<div id="div1">
<div>
<input type="file" name ="file" /><input type="button" value="添加" onclick="addfile()" /><br/>
</div>
</div>
<input type="submit" />
</form>
</body>
</html>
实现文件上传的servlet
package com.learning.servlet;
import java.io.file;
import java.io.fileoutputstream;
import java.io.ioexception;
import java.io.inputstream;
import java.io.unsupportedencodingexception;
import java.text.simpledateformat;
import java.util.date;
import java.util.list;
import java.util.uuid;
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;
import org.apache.commons.io.filenameutils;
/**
* servlet implementation class uploadservlet
*/
@webservlet("/servlet/uploadservlet")
public class uploadservlet extends httpservlet {
private static final long serialversionuid = 1l;
/**
* @see httpservlet#doget(httpservletrequest request, httpservletresponse response)
*/
protected void dopost(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {
doget(request, response);
}
/**
* @see httpservlet#dopost(httpservletrequest request, httpservletresponse response)
*/
protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {
//文件上传
//判断是否支持文件上传
boolean ismultipartcontent = servletfileupload
.ismultipartcontent(request);
if (!ismultipartcontent) {
throw new runtimeexception("不支持");
}
// 创建一个diskfileitemfactory工厂类
diskfileitemfactory diskfileitemfactory=new diskfileitemfactory();
// 创建一个servletfileupload核心对象
servletfileupload fileupload=new servletfileupload(diskfileitemfactory);
//设置中文乱码
fileupload.setheaderencoding("utf-8");
//设置一个文件大小
fileupload.setfilesizemax(1024*1024*3); //大小为3m
//设置总文件大小
//fileupload.setsizemax(1024*1024*10);//大小为10m
try {
//fileload解析request请求，返回list<fileitem>集合
list<fileitem> fileitems = fileupload.parserequest(request);
for (fileitem fileitem : fileitems) {
if (fileitem.isformfield()) {
//是文本域 (处理文本域的函数)
processformfield(fileitem);
}else {
//文件域 (处理文件域的函数)
processuploadfield1(fileitem);
}
}
} catch (fileuploadexception e) {
e.printstacktrace();
}
}
/**
* @param fileitem
*
*/
private void processuploadfield1(fileitem fileitem) {
try {
//获得文件读取流
inputstream inputstream = fileitem.getinputstream();
//获得文件名
string filename = fileitem.getname();
//对文件名处理
if (filename!=null) {
filename.substring(filename.lastindexof(file.separator)+1);
}else {
throw new runtimeexception("文件名不存在");
}
//对文件名重复处理
// filename=new string(filename.getbytes("iso-8859-1"),"utf-8");
filename=uuid.randomuuid()+"_"+filename;
//日期分类
simpledateformat simpledateformat=new simpledateformat("yyyy-mm-dd");
string date = simpledateformat.format(new date());
//创建目录
file parent=new file(this.getservletcontext().getrealpath("/web-inf/upload/"+date));
if (!parent.exists()) {
parent.mkdirs();
}
//上传文件
fileitem.write(new file(parent, filename));
//删除临时文件（如果上传文件过大，会产生.tmp的临时文件）
fileitem.delete();
} catch (ioexception e) {
system.out.println("上传失败");
e.printstacktrace();
} catch (exception e) {
}
}
/**
* @param fileitem
*/
//文件域
private void processuploadfield(fileitem fileitem) {
try {
//获得文件输入流
inputstream inputstream = fileitem.getinputstream();
//获得是文件名字
string filename = fileitem.getname();
//对文件名字处理
if (filename!=null) {
// filename.substring(filename.lastindexof(file.separator)+1);
filename = filenameutils.getname(filename);
}
//获得路径，创建目录来存放文件
string realpath = this.getservletcontext().getrealpath("/web-inf/load");
file storedirectory=new file(realpath);//既代表文件又代表目录
//创建指定目录
if (!storedirectory.exists()) {
storedirectory.mkdirs();
}
//防止文件名一样
filename=uuid.randomuuid()+"_"+filename;
//目录打散 防止同一目录文件下文件太多，不好查找
//按照日期分类存放上传的文件
//storedirectory = makechilddirectory(storedirectory);
//多级目录存放上传的文件
storedirectory = makechilddirectory(storedirectory,filename);
fileoutputstream fileoutputstream=new fileoutputstream(new file(storedirectory, filename));
//读取文件，输出到指定的目录中
int len=1;
byte[] b=new byte[1024];
while((len=inputstream.read(b))!=-1){
fileoutputstream.write(b, 0, len);
}
//关闭流
fileoutputstream.close();
inputstream.close();
} catch (ioexception e) {
e.printstacktrace();
}
}
//按照日期来分类
private file makechilddirectory(file storedirectory) {
simpledateformat simpledateformat=new simpledateformat("yyyy-mm-dd");
string date = simpledateformat.format(new date());
//创建目录
file childdirectory=new file(storedirectory, date);
if (!childdirectory.exists()) {
childdirectory.mkdirs();
}
return childdirectory;
}
//多级目录
private file makechilddirectory(file storedirectory, string filename) {
filename=filename.replaceall("-", "");
file childdirectory =new file(storedirectory, filename.charat(0)+file.separator+filename.charat(1));
if (!childdirectory.exists()) {
childdirectory.mkdirs();
}
return childdirectory;
}
//文本域
private void processformfield(fileitem fileitem) {
//对于文本域的中文乱码，可以用new string()方式解决
try {
string fieldname = fileitem.getfieldname();//表单中字段名name，如description
string fieldvalue = fileitem.getstring("utf-8");//description中value
// fieldvalue=new string(fieldvalue.getbytes("iso-8859-1"),"utf-8");
system.out.println(fieldname +":"+fieldvalue);
} catch (unsupportedencodingexception e) {
// todo auto-generated catch block
e.printstacktrace();
}
}
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。