不指定虚拟路径的前提下通过http访问pdf、图片等文件

　　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:

原文地址：https://www.cnblogs.com/qlqwjy/p/9510878.html