package upload;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;

@WebServlet(urlPatterns={"/upload.do"})

//這個註解是可以配置資訊的，比如檔案臨時存放目錄，檔案大小等等
@MultipartConfig()

public class uploadServlet extends HttpServlet{
	@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 {
		resp.setContentType("text/html");
		resp.setCharacterEncoding("utf-8");
		Part part = req.getPart("Image");
		String fileName = getName(part);
		PrintWriter printWriter =  null;
		printWriter = resp.getWriter();
		if(fileName==null){
			printWriter.println("
 

請上傳有效的檔案

"); printWriter.flush(); }else{ //通過判斷限制檔案上傳的格式 if(!"png".equalsIgnoreCase(fileName.substring(fileName.indexOf('.')+1))){ printWriter.println("

只允許PNG檔案

"); printWriter.flush(); return; } String path = req.getServletContext().getRealPath(("/File/"+fileName)); part.write(path); printWriter.println("

檔名："+fileName+"

"); printWriter.println("

檔案大小："+part.getSize()+"

"); printWriter.flush(); } if(printWriter!=null){ printWriter.close(); } } private String getName(Part part){ String name = null; String ct = part.getContentType(); if(part==null) return name; if(ct==null) return name ;//當執行檔案上傳的時候，ContentType不為空 String disposition = part.getHeader("content-disposition"); String[] elements = disposition.split(";"); for(String ele:elements){ if(ele.trim().startsWith("filename")){ name = ele.substring(ele.indexOf('=')+1).trim().replace("\"", ""); return name; }else{ continue; } } return name; } }