通常我们通过http访问图片或者pdf的时候都是将文件上传到指定文件夹下面，然后通过配置虚拟路径来访问指定的资源。
在不配置虚拟路径的情况下，我们通过获取到response的outpurstream，然后向该outputstream输出指定的文件也可以，用IOUtils工具类更是简单方便。
例如:
依赖的包:
package cn.qlq.web;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.ServletOutputStream;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.apache.commons.io.IOUtils;/** * Servlet implementation class TestServlet */@WebServlet("/TestServlet")public class TestServlet extends HttpServlet { ???private static final long serialVersionUID = 1L; ???/** ????* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse ????* ?????response) ????*/ ???protected void doGet(HttpServletRequest request, HttpServletResponse response) ???????????throws ServletException, IOException { ???????FileInputStream in = null; ???????ServletOutputStream outputStream = null; ???????try { ???????????in = new FileInputStream(new File("C:\\Users\\Administrator\\Desktop\\测试文档\\Java开发-太原科技大学-软件工程-乔利强.pdf")); ???????????outputStream = response.getOutputStream(); ???????????IOUtils.copyLarge(in, outputStream); ???????} catch (Exception e) { ???????????e.printStackTrace(); ???????} finally { ???????????IOUtils.closeQuietly(in); ???????????IOUtils.closeQuietly(outputStream); ???????} ???} ???/** ????* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse ????* ?????response) ????*/ ???protected void doPost(HttpServletRequest request, HttpServletResponse response) ???????????throws ServletException, IOException { ???????// TODO Auto-generated method stub ???????doGet(request, response); ???}}测试:
不指定虚拟路径的前提下通过http访问pdf、图片等文件
原文地址：https://www.cnblogs.com/qlqwjy/p/9510878.html