限制上传：
类型、
大小
注意 对文件的限制条件 写再parseRequest之前
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="UploadServlet" method ="post" enctype="multipart/form-data">
学号：<input name="sno" /><br/>
姓名：<input name="sname" /><br/>
上传文件：<input type="file" name="mydoc"/><br/>
<input type="submit" value="上传">
</form>
</body>
</html>package org.student.servlet;
import java.io.File;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import javax.servlet.ServletException;
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.FileUploadBase;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import sun.awt.datatransfer.DataTransferer.ReencodingInputStream;
/**
* Servlet implementation class UploadServlet
*/
public class UploadServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
response.setContentType("text/html; charset=UTF-8");
// 上传
// request.getParameter("sname")
try {
boolean isMultipart = ServletFileUpload.isMultipartContent(request);
if (isMultipart) {// 判断前台的form是否有 mutipart属性
// FileItemFactory factory = new DiskFileItemFactory();
DiskFileItemFactory factory = new DiskFileItemFactory();
ServletFileUpload upload = new ServletFileUpload(factory);
//设置上传文件时 用到的临时文件的大小DiskFileItemFactory
factory.setSizeThreshold(10240);//设置临时的缓冲文件大小为10
factory.setRepository(new File("D:\\upload\\temp"));//设置临时文件的目录
//控制上传单个文件的大小 20KB ServletFileUpload
upload.setSizeMax(20480);//字节B
Thread.sleep(3000);
// 通过parseRequest解析form中的所有请求字段，并保存到 items集合中（即前台传递的sno sname
// spicture此时就保存在了items中）
List<FileItem> items = upload.parseRequest(request);
// 遍历items中的数据（item=sno sname spicture）
Iterator<FileItem> iter = items.iterator();
while (iter.hasNext()) {
FileItem item = iter.next();
String itemName = item.getFieldName();
int sno = -1;
String sname = null;
// 判断前台字段 是普通form表单字段(sno sname)，还是文件字段
// request.getParameter() -- iter.getString()
if (item.isFormField()) {
if (itemName.equals("sno")) {// 根据name属性 判断item是sno sname 还是spicture?
sno = Integer.parseInt(item.getString("UTF-8"));
} else if (itemName.equals("sname")) {
sname = item.getString("UTF-8");
} else {
System.out.println("其他字段xxx.....");
}
} else {// spicture 123
// 文件 上传
// 文件名 getFieldName是获取 普通表单字段的Name值
// getName()是获取 文件名
String fileName = item.getName();//a.txt a.docx a.png
String ext = fileName.substring( fileName.indexOf(".")+1 ) ;
if(!(ext.equals("png") || ext.equals("gif") ||ext.equals("jpg"))) {
System.out.println("图片类型有误！格式只能是 png gif jpg");
return ;//终止
}
// 获取文件内容 并上传
// 定义文件路径：指定上传的位置(服务器路径)
// 获取服务器路径D:\\study\\apache-tomcat-8.5.30\\wtpwebapps\\UpAndDown\\upload
// String path =request.getSession().getServletContext().getRealPath("upload") ;
String path = "D:\\upload";
File file = new File(path, fileName);
item.write(file);// 上传
System.out.println(fileName + "上传成功！");
return;
}
}
}
}
catch (FileUploadBase.SizeLimitExceededException e) {//SizeLimitExceededException是FileUploadException的一个子类
System.out.println("上传文件大小超过限制！最大20KB");
}
catch (FileUploadException e)
{
e.printStackTrace();
}
// 解析请求
catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
