1.导入jar包：commons-io-1.4.jar
2.index.jsp:
1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> 2 <% 3 String path = request.getContextPath(); 4 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; 5 %> 6 7 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 8 <html> 9 <head> 10 <base href="<%=basePath%>"> 11 12 <title>文件上传</title> 13 <meta http-equiv="pragma" content="no-cache"> 14 <meta http-equiv="cache-control" content="no-cache"> 15 <meta http-equiv="expires" content="0"> 16 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> 17 <meta http-equiv="description" content="This is my page"> 18 <!-- 19 <link rel="stylesheet" type="text/css" href="styles.css"> 20 --> 21 </head> 22 23 <body> 24 <div><a href="${pageContext.request.contextPath}/showPic.jsp">查看图片</a></div> 25 </body> 26 </html>
3.showPic.jsp
1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> 2 <% 3 String path = request.getContextPath(); 4 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; 5 %> 6 7 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 8 <html> 9 <head> 10 <base href="<%=basePath%>"> 11 12 <title>文件上传</title> 13 <meta http-equiv="pragma" content="no-cache"> 14 <meta http-equiv="cache-control" content="no-cache"> 15 <meta http-equiv="expires" content="0"> 16 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> 17 <meta http-equiv="description" content="This is my page"> 18 <!-- 19 <link rel="stylesheet" type="text/css" href="styles.css"> 20 --> 21 </head> 22 23 <body> 24 <div> 25 <img alt="图片" src="${pageContext.request.contextPath}/ShowPictureServlet?fileName=fanfan.jpg"> 26 </div> 27 </body> 28 </html>
4.ShowPictureServlet.java
pacgake com.pearl.util;
1 import java.io.File; 2 import java.io.FileInputStream; 3 import java.io.IOException; 4 import java.io.OutputStream; 5 6 import javax.servlet.ServletConfig; 7 import javax.servlet.ServletException; 8 import javax.servlet.http.HttpServlet; 9 import javax.servlet.http.HttpServletRequest; 10 import javax.servlet.http.HttpServletResponse; 11 12 public class ShowPictureServlet extends HttpServlet { 13 14 public void destroy() { 15 super.destroy(); 16 } 17 18 public void doGet(HttpServletRequest request, HttpServletResponse response) 19 throws ServletException, IOException { 20 //文件路径 21 String picFolder = "E:/upload/"; 22 String fileName = request.getParameter("fileName"); 23 if(fileName!=null && !fileName.equals("")){ 24 String mimeType = "image/gif"; 25 //设置content类型 26 response.setContentType(mimeType); 27 //设置大小 28 File file = new File(picFolder + fileName); 29 response.setContentLength((int) file.length()); 30 //打开文件并输出 31 FileInputStream inputStream = new FileInputStream(file); 32 OutputStream out = response.getOutputStream(); 33 34 //把文件复制到输出流 35 byte[] data = new byte[1024]; 36 int count = 0; 37 while ((count=inputStream.read(data))>=0){ 38 out.write(data, 0, count); 39 } 40 inputStream.close(); 41 out.close(); 42 } 43 } 44 45 public void doPost(HttpServletRequest request, HttpServletResponse response) 46 throws ServletException, IOException { 47 doGet(request, response); 48 } 49 50 51 public void init(ServletConfig config) throws ServletException { 52 super.init(config); 53 } 54 55 }
5.web.xml
1 <?xml version="1.0" encoding="UTF-8"?> 2 <web-app version="2.5" 3 xmlns="http://java.sun.com/xml/ns/javaee" 4 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 5 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 6 http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> 7 <servlet> 8 <description>This is the description of my J2EE component</description> 9 <display-name>This is the display name of my J2EE component</display-name> 10 <servlet-name>ShowPictureServlet</servlet-name> 11 <servlet-class>com.pearl.util.ShowPictureServlet</servlet-class> 12 </servlet> 13 14 <servlet-mapping> 15 <servlet-name>ShowPictureServlet</servlet-name> 16 <url-pattern>/ShowPictureServlet</url-pattern> 17 </servlet-mapping> 18 19 <welcome-file-list> 20 <welcome-file>index.jsp</welcome-file> 21 </welcome-file-list> 22 </web-app>
6.完成。