JAVA使用commos-fileupload实现文件上传与下载实例解析
程序员文章站
2024-03-08 14:45:05
首先给大家介绍一文件的上传
实体类
import java.sql.timestamp;
/**
*
* @decription 文件上传实体...
首先给大家介绍一文件的上传
实体类
import java.sql.timestamp;
/**
*
* @decription 文件上传实体类
*
*/
public class upfile {
private string id;// id主键 使用uuid随机生成
private string uuidname; // uuid名称
private string filename;//文件名称
private string savepath; // 保存路径
private timestamp uploadtime; // 上传时间
private string description;// 文件描述
private string username; // 用户名
public upfile() {
super();
}
public upfile(string id, string uuidname, string filename, string savepath,
timestamp uploadtime, string description, string username) {
super();
this.id = id;
this.uuidname = uuidname;
this.filename = filename;
this.savepath = savepath;
this.uploadtime = uploadtime;
this.description = description;
this.username = username;
}
public string getdescription() {
return description;
}
public string getfilename() {
return filename;
}
public string getid() {
return id;
}
public string getsavepath() {
return savepath;
}
public timestamp getuploadtime() {
return uploadtime;
}
public string getusername() {
return username;
}
public string getuuidname() {
return uuidname;
}
public void setdescription(string description) {
this.description = description;
}
public void setfilename(string filename) {
this.filename = filename;
}
public void setid(string id) {
this.id = id;
}
public void setsavepath(string savepath) {
this.savepath = savepath;
}
public void setuploadtime(timestamp uploadtime) {
this.uploadtime = uploadtime;
}
public void setusername(string username) {
this.username = username;
}
public void setuuidname(string uuidname) {
this.uuidname = uuidname;
}
}
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%>">
<title>my jsp 'upload.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">
-->
</head>
<body>
<h1>文件上传</h1>
<form action="${pagecontext.request.contextpath }/upload" method="post" enctype="multipart/form-data">
<table>
<tr>
<td> 上传用户名:</td>
<td><input type="text" name="username"/></td>
</tr>
<tr>
<td> 上传文件:</td>
<td><input type="file" name="file"/></td>
</tr>
<tr>
<td> 描述:</td>
<td><textarea rows="5" cols="50" name="description"></textarea></td>
</tr>
<tr>
<td><input type="submit" value="上传开始"/></td>
</tr>
</table>
</form>
<div>${msg }</div>
<a href="${pagecontext.request.contextpath }/index.jsp">返回主页</a>
</body>
</html>
servlet
import java.io.ioexception;
import javax.servlet.servletexception;
import javax.servlet.http.httpservlet;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
import org.apache.commons.fileupload.fileuploadbase.filesizelimitexceededexception;
import org.apache.commons.fileupload.fileuploadbase.sizelimitexceededexception;
import org.apache.commons.fileupload.servlet.servletfileupload;
import com.itheima.domain.upfile;
import com.itheima.exception.myexception;
import com.itheima.service.upfileservice;
import com.itheima.service.impl.upfileserviceimpl;
import com.itheima.untils.webuntil;
public class uploadfileservlet extends httpservlet {
public void doget(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception {
dopost(request, response);
}
public void dopost(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception {
//判断表单是不是多个部分组成的
if(!servletfileupload.ismultipartcontent(request)){
request.setattribute("msg", "表单个设置错误,请检查enctype属性是是否设置正确");
request.getrequestdispatcher("/upload.jsp").forward(request, response);
return ;
}
//是多部分组成的就获取并遍历返回一个文件上传对象,包含上传的所有信息
try {
upfile upfile=webuntil.upload(request);
upfileservice upfileservice=new upfileserviceimpl();
boolean flag=upfileservice.add(upfile);
if(flag){
request.setattribute("msg", "上传成功");
request.getrequestdispatcher("/upload.jsp").forward(request, response);
return ;
}else{
request.setattribute("msg", "上传失败,请重试");
request.getrequestdispatcher("/upload.jsp").forward(request, response);
return ;
}
}catch (filesizelimitexceededexception e) {
e.printstacktrace();
request.setattribute("msg", "单个文件大小 ,超过最大限制");
request.getrequestdispatcher("/upload.jsp").forward(request, response);
return ;
} catch (sizelimitexceededexception e) {
e.printstacktrace();
request.setattribute("msg", "总文件大小 ,超过最大限制");
request.getrequestdispatcher("/upload.jsp").forward(request, response);
return ;
}
}
}
工具类
import java.io.file;
import java.io.filenotfoundexception;
import java.io.fileoutputstream;
import java.io.ioexception;
import java.io.inputstream;
import java.io.outputstream;
import java.io.unsupportedencodingexception;
import java.util.arraylist;
import java.util.list;
import java.util.uuid;
import javax.servlet.http.httpservletrequest;
import org.apache.commons.fileupload.fileitem;
import org.apache.commons.fileupload.fileuploadbase;
import org.apache.commons.fileupload.fileuploadbase.filesizelimitexceededexception;
import org.apache.commons.fileupload.fileuploadbase.sizelimitexceededexception;
import org.apache.commons.fileupload.fileuploadexception;
import org.apache.commons.fileupload.progresslistener;
import org.apache.commons.fileupload.disk.diskfileitemfactory;
import org.apache.commons.fileupload.servlet.servletfileupload;
import com.itheima.domain.upfile;
import com.itheima.exception.myexception;
/**
* 文件上传工具类
* @decription todo
*
*/
public class webuntil {
/**
* 文件上传的方法
* @param request 请求参数传入
* @return 返回一个upfile对象
* @throws filesizelimitexceededexception
* @throws sizelimitexceededexception
* @throws ioexception
*/
public static upfile upload(httpservletrequest request) throws filesizelimitexceededexception, sizelimitexceededexception {
upfile upfile=new upfile();
arraylist<string> filelist=initlist();
try {
//获取磁盘文件对象工厂
diskfileitemfactory factory=new diskfileitemfactory();
string tmp=request.getsession().getservletcontext().getrealpath("/tmp");
system.out.println(tmp);
//初始化工厂
setfactory(factory,tmp);
//获取文件上传解析器
servletfileupload upload=new servletfileupload(factory);
//初始化解析器
setupload(upload);
//获取文件列表集合
list<fileitem> list = upload.parserequest(request);
//遍历
for (fileitem items : list) {
//判断 是不是普通表单个对象
if(items.isformfield()){
//获取上传表单的name
string fieldname=items.getfieldname();
//value
string fieldvalue=items.getstring("utf-8");
//判断
if("username".equals(fieldname)){
//设置
upfile.setusername(fieldvalue);
}else if("description".equals(fieldname)){
//设置属性
upfile.setdescription(fieldvalue);
}
}else{
//是文件就准备上传
//获取文件名
string filename=items.getname();
//处理因为浏览器不同而导致的 获得 的 文件名的 差异
int index=filename.lastindexof("\\");
if(index!=-1){
filename=filename.substring(index+1);
}
//生成随机的文件名
string uuidname=generatefilename(filename);
//获取上传的文件路径
string savepath=request.getsession().getservletcontext().getrealpath("/web-inf/upload");
//获取请求对象中的输入流
inputstream in = items.getinputstream();
//将文件打散存放在不同的路径,求出路径
savepath=generaterandomdir(savepath,uuidname);
//复制文件
uploadfile(in,savepath,uuidname);
string id=uuid.randomuuid().tostring();
upfile.setid(id);
upfile.setsavepath(savepath);
upfile.setuuidname(uuidname);
upfile.setfilename(filename);
//清除缓存
items.delete();
}
}
}catch ( fileuploadbase.filesizelimitexceededexception e) {
//抛出出异常
throw e;
} catch (fileuploadbase.sizelimitexceededexception e) {
//抛出出异常
throw e;
}catch (fileuploadexception e) {
e.printstacktrace();
} catch (unsupportedencodingexception e) {
e.printstacktrace();
} catch (ioexception e) {
e.printstacktrace();
} catch (exception e) {
e.printstacktrace();
}
return upfile;
}
/**
* 初始化文件列表
* @return
*/
private static arraylist<string> initlist() {
arraylist<string> list=new arraylist<string>();
list.add(".jpg");
list.add(".rar");
list.add(".txt");
list.add(".png");
return list;
}
/**
* 复制文件
* @param in items中的输入流
* @param savepath 保存路径
* @param uuidname 文件名
*/
private static void uploadfile(inputstream in, string savepath,
string uuidname) {
//获取文件
file file=new file(savepath, uuidname);
outputstream out = null;
try {
int len=0;
byte [] buf=new byte[1024];
//获取输出流
out = new fileoutputstream(file);
while((len=in.read(buf))!=-1){
out.write(buf, 0, len);
}
} catch (filenotfoundexception e) {
e.printstacktrace();
} catch (ioexception e) {
e.printstacktrace();
}finally{
try {
in.close();
} catch (ioexception e) {
e.printstacktrace();
}
try {
out.close();
} catch (ioexception e) {
e.printstacktrace();
}
}
}
/**
* 生成随机的存放路径
* @param savepath 保存路径
* @param uuidname 生成的uuid名称
* @return
* 使用hashcode完成
*/
private static string generaterandomdir(string savepath, string uuidname) {
//转化为hashcode
system.out.println("上传路径"+savepath);
system.out.println("uuidname"+uuidname);
int hashcode=uuidname.hashcode();
//容器
stringbuilder sb=new stringbuilder();
while(hashcode>0){
//与上15
int tmp=hashcode&0xf;
sb.append("/");
sb.append(tmp+"");
hashcode=hashcode>>4;
}
//拼接新的路径
string path=savepath+sb.tostring();
system.out.println("path"+path);
file file=new file(path);
//判断路径存不存在
if(!file.exists()){
//不存在就创建
file.mkdirs();
}
//返回保存路径
return path;
}
/**
* 生成新的文件名
* @param uuidname 随机的id名字
* @param filename 原来的名
* @return
*/
private static string generatefilename( string filename) {
string uuidname=uuid.randomuuid().tostring();
return uuidname.replace("-", "").tostring()+"_"+filename;
}
/**
* 初始化解析器
* @param upload
*/
private static void setupload(servletfileupload upload) {
// 设置 字符编码
upload.setheaderencoding("utf-8");
//设置文件大小
upload.setfilesizemax(1024*1024*20);
//设置总文件大小
upload.setsizemax(1024*1024*50);
//设置进度监听器
upload.setprogresslistener(new progresslistener() {
public void update(long pbytesread, long pcontentlength, int pitems) {
system.out.println("已经读取: "+pbytesread+",总共有: "+pcontentlength+", 第"+pitems+"个");
}
});
}
/**
* 工厂初始化方法
* @param factory
* @param tmp 缓冲目录
*/
private static void setfactory(diskfileitemfactory factory, string tmp) {
/// 配置初始化值缓冲区
factory.setsizethreshold(1024*1024);
file file=new file(tmp);
//设置缓冲目录
factory.setrepository(file);
}
}
二文件下载
servlet
public class downupfileservlet extends httpservlet {
public void doget(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception {
dopost(request, response);
}
public void dopost(httpservletrequest request, httpservletresponse response)
throws servletexception, ioexception {
//获取id
string id=request.getparameter("id");
//业务层的接口
upfileservice upfileservice=new upfileserviceimpl();
//根据id查找这个对象
upfile upfile=upfileservice.findupfilebyid(id);
if(upfile==null){
return;
}
//获取文件的真实名称
string filename=upfile.getfilename();
//如果文件名中有中文,需要转码,不然就下载时没有文件名
filename=urlencoder.encode(filename, "utf-8");
//更改过的名称
string uuidname=upfile.getuuidname();
//保存路径
string savepath=upfile.getsavepath();
file file=new file(savepath,uuidname);
//判断文件 是否存在
if(!file.exists()){
request.setattribute("msg", "下载 的文件过期了");
request.getrequestdispatcher("/index").forward(request, response);
return;
}
//设置文件下载响应头信息
response.setheader("content-disposition", "attachement;filename="+filename);
//使用io流输出
inputstream in = new fileinputstream(file);
servletoutputstream out = response.getoutputstream();
int len=0;
byte [] buf=new byte[1024];
while((len=in.read(buf))!=-1){
out.write(buf, 0, len);
}
in.close();
}
}
数据库
create database upload_download_exercise; use upload_download_exercise; create table upfiles( id varchar(100), //使用uuid生成 uuidname varchar(255),//uuid加上原来的文件名 filename varchar(100),//真实文件名 savepath varchar(255),//保存路径 uploadtime timestamp,//上传时间 description varchar(255),//描述 username varchar(10) 上传人 );
以上所述是小编给大家分享的java使用commos-fileupload实现文件上传与下载的相关内容，希望对大家有所帮助。