文件上传

package cn.servlet;

import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.UUID;

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.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;

@WebServlet(urlPatterns = "/up2")
public class Up2Servlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");

        DiskFileItemFactory disk = new DiskFileItemFactory();
        ServletFileUpload up = new ServletFileUpload(disk);
        // 如果你不知道用户上传多少个文件，则应该遍历
        try {
            List<FileItem> list = up.parseRequest(req);
            FileItem item1 = list.get(0);
            String name = item1.getString("UTF-8");// 对于非文件，用于这种方式来获取用户提交的
            FileItem item2 = list.get(1);
            String age = item2.getString("UTF-8");
            FileItem item3 = list.get(2);
            String fileName = item3.getName();
            fileName = fileName.substring(fileName.lastIndexOf("\\") + 1);
            // 对文件重名称
            String extName = fileName.substring(fileName.lastIndexOf(".") + 1);// abc.jpg
                                                                                // -=>
                                                                                // jpg
            String uuid = UUID.randomUUID().toString().replace("-", "");
            String newFileName = uuid + "." + extName;
            // 获取文件上传的真实的目录
            String realPath = getServletContext().getRealPath("/files");
            // 实现文件上传
            item3.write(new File(realPath, newFileName));
            // 将转发到show.jsp显示
            req.setAttribute("name", name);
            req.setAttribute("age", age);
            req.setAttribute("oldFileName", fileName);
            req.setAttribute("newFileName", newFileName);
            req.getRequestDispatcher("/jsps/show.jsp").forward(req, resp);
        } catch (Exception e) {
            e.printStackTrace();
        }

    }
}