FileUpload框架实现文件上传(多个文件)和下载

一、文件上传：

　　对于大文件执行下面的代码之间卡死

package com.example.web.service.servlet;

import java.io.File;
import java.io.IOException;
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.FileItemFactory;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
public class FileUpload extends HttpServlet {
    private static final long serialVersionUID = 1L;
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        try {
            FileItemFactory factory = new DiskFileItemFactory();
            ServletFileUpload upload = new ServletFileUpload(factory);
            List<FileItem> items = upload.parseRequest(request);
            String dir = request.getSession().getServletContext().getRealPath("/files");
            File dirFile= new File(dir);
            if(!dirFile.exists())
                dirFile.mkdirs();
            for (FileItem fileItem : items) {
                //文本类型
                if(fileItem.isFormField()){
                    String name =fileItem.getFieldName();
                    String value=fileItem.getString();
                    System.out.println(" name: "+name+" value: "+value);
                }else {
                    System.out.println(" 上传文件目录: "+dir);
                    File saveFile = new File(dir,fileItem.getName());
                    fileItem.write(saveFile);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

　　jsp界面，上传文件时form表单必须有 enctype="multipart/form-data"

<form action="<%=request.getContextPath() %>/FileUpload" method="post" enctype="multipart/form-data">
        <input type="text" name="name" > <br>
        <input type="file" name="file1"> <br>
        <input type="file" name="file2"> <br>
        <input type="submit" value=" submit ">
</form>