一、文件上传
jar包：commons-fileupload-1.3.3.jar，commons-io-2.5.jar
简说流程：request<file>-->Servlet.service(转化request携带的数据,获取输入流)-->通过输出流写到服务器磁盘
1、upload.jsp
<%@ 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>
<title>文件上传</title>
</head>
<body>
<form action="${pageContext.request.contextPath}/uploadServlet" method="post" enctype="multipart/form-data">
上传文件1：<input type="file" name="file_1" size="40">
上传文件2：<input type="file" name="file_2" size="40">
<input type="submit" value="提交"></form>
</body>
</html>
2、UploadServlet.java
public class UploadServlet extends HttpServlet
{
/**
* 注释内容
*/
private static final long serialVersionUID = -3592230091955074245L;
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException
{
System.out.println("i'm in uploadServlet service method");
String resultMsg="";
//获取真实保存的路径
String savePath=req.getServletContext().getRealPath("/WEB-INF/upload");
System.out.println("文件保存的路劲："+savePath);
File file = new File(savePath);
//这个路径是否是个文件夹
if(file.isDirectory() || !file.exists())
{
file.mkdir();
}
DiskFileItemFactory factory = new DiskFileItemFactory();
//设置默认缓存大小
factory.setSizeThreshold(DiskFileItemFactory.DEFAULT_SIZE_THRESHOLD);
ServletFileUpload upload = new ServletFileUpload(factory);
upload.setHeaderEncoding("UTF-8");
//设置文件大小限制
upload.setFileSizeMax(40*1024*1024);
//这里很重要 是这个数据格式的支持多媒体multipart/form-data 在JSP上传页面中也要写上
if(!ServletFileUpload.isMultipartContent(req))
{
//按照传统方式获取数据
System.out.println("数据格式不正确");
return;
}
try
{
List<FileItem> list = upload.parseRequest(req);
for(FileItem item : list)
{
//从request总获取数据，有可能是表单提交的文本键值
if(!item.isFormField())
{
System.out.println("处理上传文件中");
String filename = item.getName();
//判断上传路径是否合法
if(filename==null || filename.trim().equals(""))
{
continue;
}
//获取上传文件名
filename = filename.substring(filename.lastIndexOf("\\")+1);
InputStream in = item.getInputStream();
FileOutputStream out = new FileOutputStream(savePath + "\\" + filename);
byte buffer[] = new byte[1024];
int len = -1;
while((len=in.read(buffer))>0)
{
out.write(buffer, 0, len);
}
in.close();
out.close();
item.delete();
}
}
resultMsg="上传文件成功";
}
catch (FileUploadException e)
{
resultMsg="上传失败";
e.printStackTrace();
}
req.setAttribute("resultMsg", resultMsg);
req.getRequestDispatcher("/upload_result.jsp").forward(req, resp);
}}
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