1、首先导入:commons-fileupload-1.3.3.jar和commons-io-2.5.jar
2、创建upload.jsp页面
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<!-- enctype="multipart/form-data":设定表单的上传类型为二进制类型-->
<form action="<%=request.getContextPath() %>/upload" method="post" enctype="multipart/form-data">
用户名:<input type="text" name="username"/><br/>
<input type="file" name="myfile"/><br/>
<input type="submit" value="上传"/>
</form>
</body>
</html>
3、servlet
package com.hx.shopping.web;
import java.awt.SystemColor;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
import java.text.SimpleDateFormat;
import java.util.stream.Stream;
import javax.servlet.ServletContext;
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.FileItemIterator;
import org.apache.commons.fileupload.FileItemStream;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import org.apache.commons.fileupload.util.Streams;
import org.apache.commons.io.FileUtils;
@WebServlet("/upload")
public class LoadServlet extends HttpServlet{
private static final long serialVersionUID = 1L;
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//当表单上传类型改为二进制类型时,此方法不再能接收传过来的字段 String username = req.getParameter("username");
//判断是否是文件请求
boolean isMultipart = ServletFileUpload.isMultipartContent(req);
try {
if(isMultipart){
//创建一个新的文件上传处理器
ServletFileUpload upload = new ServletFileUpload();
//产生一个迭代器
FileItemIterator iter = upload.getItemIterator(req);
while(iter.hasNext()){
//传过来的是多个文本域的流,FileItemStream:获得单个文本域的流
FileItemStream item = iter.next();//FileInputStream 用于读取诸如图像数据之类的原始字节流。要读取字符流,请考虑使用 FileReader。
//获取字段名字:username、myfile
String name = item.getFieldName();
//打开流,打开才能使用
InputStream istream = item.openStream();
//判断是否是普通的表单字段
if(item.isFormField()){
//Streams.asString(istream):将流转换成字符串
System.out.println("form filed:"+name+",value:"+Streams.asString(istream));
}else{
//getServletContext():获得一个ServletContext对象(一个全局的储存信息的空间,服务器开始就存在,服务器关闭才释放。所有用户共用一个) getContextPath():获取跟路径/Shopping4
String filePath = req.getSession().getServletContext().getRealPath("/upload");//eclipse临时文件路径:E:\Lay\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\Shopping4\ upload
//拼接上文件名
String tail = item.getName().substring(item.getName().indexOf("."));
//使用时间戳来为上传的文件命名,避免不可重复上传的问题
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddhhmmssSSS");//SSS具体到毫秒数
String timeName = sdf.format(new Date());
filePath += "/"+timeName+tail;
//将流拷贝到文件中去
FileUtils.copyInputStreamToFile(istream, new File(filePath));// new File(filePath):自动创建文件夹
}
}
}
} catch (Exception e) {
e.printStackTrace();
}
}
}