jsp+servlet简单实现上传文件功能（保存目录改进）
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2022-03-07 18:55:37
1、jsp前端<%-- created by intellij idea. user: lenovo date: 2020/6/19 time: 22:53 learn from https:/...
1、jsp前端
<%--
created by intellij idea.
user: lenovo
date: 2020/6/19
time: 22:53
learn from https://www.bilibili.com/video/bv18z411i7gh?t=23&p=192
to change this template use file | settings | file templates.
--%>
<%@ page contenttype="text/html;charset=utf-8" language="java" %>
<html>
<head>
<title>文件上传</title>
</head>
<body>
<!--文件上传对表单的要求-->
<!--
1、表单中的请求提交方式必须是post
2、表单中应指定所提交的请求位multipart请求，通过在<form/>标签中添加enctype属性
其值为multipart/form-data
3、 表单
-->
<form method="post" action="http://localhost:8888/hello/uploadimageservlet" enctype="multipart/form-data">
编号<input type="text" name="bno"></br>
名字<input type="text" name="bname"></br>
照片<input type="file" name="picutreurl"></br>
<input type="submit" value="注册">
</form>
</body>
</html>
2、servlet后台
package servlet.bookservlet;
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 javax.servlet.servletexception;
import javax.servlet.annotation.webservlet;
import javax.servlet.http.httpservlet;
import javax.servlet.http.httpservletrequest;
import javax.servlet.http.httpservletresponse;
import java.io.*;
import java.text.simpledateformat;
import java.util.calendar;
import java.util.date;
import java.util.list;
@webservlet(name = "uploadimageservlet")
public class uploadimageservlet extends httpservlet {
@override
protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {
this.dopost(request,response);
}
@override
protected void dopost(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {
//1、判断请求是不是multipart请求
if(!servletfileupload.ismultipartcontent(request)){
throw new runtimeexception("当前请求不支持文件上传");
}
system.out.println("开始上传文件");
//2、创建fileitem工厂==>文件写入硬盘的作用
try {
diskfileitemfactory factory = new diskfileitemfactory();
//3、创建temp临时文件夹
string temppath ="d:\\tomcat\\apache-tomcat-9.0.35-windows-x64\\apache-tomcat-9.0.35\\webapps\\librarysystem\\web\\net\\temp";
file tempfile = new file(temppath);
factory.setrepository(tempfile);
//4、设置使用临时文件的边界值,大于该值，上传文件先保存在临时文件中，小于该值，则直接写入内存
//单位是字节
factory.setsizethreshold(1024*1024*1);
//5、创建文件上传核心组件
// 调用servletfileupload.parserequest方法解析request对象，得到一个保存了所有上传内容的list对象。
servletfileupload upload = new servletfileupload(factory);
upload.setheaderencoding("utf-8");//可以解决文件名中文乱码
upload.setfilesizemax(1024*1024*2);
string bno="defaultbno",bname="defaultbname";
//6、解析请求
list<fileitem> items =upload.parserequest(request);
//7、遍历请求
for(fileitem item:items){
//普通表单项，上传名字，编号等普通信息的上i传
if(item.isformfield()){
string filename = item.getfieldname();// name属性值
string filevalue = item.getstring("utf-8");// name对应的value值
system.out.println(filename + " -- " + filevalue);
if(filename.equalsignorecase("bno")){
bno = filevalue;
}
if(filename.equalsignorecase("bname")){
bname = filevalue;
}
}
else{//上传图片等
string filename = item.getname();
system.out.println("上传文件名字:"+filename);
string suffix = filename.substring(filename.lastindexof('.'));//获取文件类型
string newfilename = bno+"_"+bname+suffix;
system.out.println(newfilename);
//获取输入流，其中有上传文件的内容
inputstream is = item.getinputstream();
//string path = this.getservletcontext().getrealpath("/net/bookimage");//获得当前项目保存服务器地址，也就是web文件夹下
string path ="d:\\tomcat\\apache-tomcat-9.0.35-windows-x64\\apache-tomcat-9.0.35\\webapps\\librarysystem\\web\\net\\bookimage";
//文件夹内文件数目有上限，但是可以创建子目录
//获取当前系统时间
calendar now = calendar.getinstance();
int year = now.get(calendar.year);
int month = now.get(calendar.month)+1;
int day = now.get(calendar.day_of_month);
path = path+"/"+year+"/"+month+"/"+day;
//若该目录不存在，直接创建新目录
file dirfile = new file(path);
if(!dirfile.exists()){
dirfile.mkdirs();
}
//创建目标文件，用来保存上传文件
file desfile = new file(path,newfilename);
//创建文件输出流
outputstream os = new fileoutputstream(desfile);
//将输入流数据写入到输出流中
int len=-1;
byte[]buf = new byte[1024];
while((len=is.read(buf))!=-1){
os.write(buf,0,len);
}
//desfile.delete();//删除临时文件
os.close();//输出流
is.close();//输入流
//删除临时文件
item.delete();
}
}
} catch (fileuploadexception e) {
e.printstacktrace();
}
}
}
总结
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