package servlet;import com.jspsmart.upload.File;
import com.jspsmart.upload.SmartUpload;
import com.jspsmart.upload.SmartUploadException;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 javax.servlet.jsp.JspFactory;
import javax.servlet.jsp.PageContext;
import java.io.IOException;@WebServlet(urlPatterns = "/uploadtest")
public class UploadServlet  extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doPost(req, resp);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {try {//1.创建上传文件的对象SmartUpload smartUpload = new SmartUpload();//2.初始化上传操作//在servlet中获取jsp的内置对象pageContext//通过工具类JspFactory.getDefaultFactory()的getPageContext()//getPageContext()中有7个参数//参1:当前servlet对象;参2:req;参3:resp;参4:字符串，传入jsp的错误页面;参5:是否使用session;参6:缓冲区大小;参7:缓冲区满了溢出部分是否加入到输出流中PageContext pageContext = JspFactory.getDefaultFactory().getPageContext(this, req, resp, null, false, 1024, true);smartUpload.initialize(pageContext);//2.1 设置编码smartUpload.setCharset("utf-8");//3.文件上传到服务器smartUpload.upload();//4.获取文件信息File file = smartUpload.getFiles().getFile(0);//获取指定下标的上传文件String fileName = file.getFileName();//获取上传的文件名String contentType = file.getContentType();//获取上传文件的类型//获取文本信息String uname = smartUpload.getRequest().getParameter("uname");System.out.println("uname="+uname);//5.指定上传的路径(设置上传的文件在服务器中保存的位置)//首先在web下创建uploadfiles文件夹，并且创建文件a.txt,因为空文件夹无法部署到服务器String uploadpath="/uploadfiles/"+fileName;//6.保存到指定位置，File.SAVEAS_VIRTUAL表示保存到虚拟路径中file.saveAs(uploadpath,File.SAVEAS_VIRTUAL);//7.跳转成功页面，在页面中显示图片req.setAttribute("filename",fileName);req.getRequestDispatcher("success.jsp").forward(req,resp);} catch (SmartUploadException e) {e.printStackTrace();}}
}

smartUpload.getRequest().getParameter("uname")

Servlet中获取JSP页面中的内置对象PageContext

JspFactory.getDefaultFactory().getPageContext(.........)

smartupload常用方法

文件下载

package servlet;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 java.io.IOException;
import java.net.URLEncoder;@WebServlet(urlPatterns = "/downimg")
public class DownServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doPost(req, resp);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {String filename = req.getParameter("filename");//获取要下载的文件名String path="/uploadfiles/"+filename;//文件路径//设置响应的数据类型--将响应的内容设置为通用的二进制流resp.setContentType("application/octet-stream");//响应的头信息，设置文件名编码格式，避免页面中下载的文件名乱码//attachment 告诉浏览器以附件的方式下载文件(弹出下载框)resp.addHeader("Content-Disposition","attachment;filename="+ URLEncoder.encode(filename,"UTF-8"));//跳转页面req.getRequestDispatcher(path).forward(req,resp);//清空缓冲区:将服务端缓冲区的文件内容,立即全部传送给客户端resp.flushBuffer();}
}

本地图片上传到服务器后，并在页面显示图片