实现一个基本防盗链标签

1. 标签处理类

 1 public class MyReferer extends BodyTagSupport {

 2     private String site;

 3     private String back;

 4     public String getSite() {

 5         return site;

 6     }

 7     public void setSite(String site) {

 8         this.site = site;

 9     }

10     public String getBack() {

11         return back;

12     }

13     public void setBack(String back) {

14         this.back = back;

15     }

16     public int doEndTag() throws JspException {

17         // 获取JSP上下文环境对象

18         PageContext pageContext = this.pageContext;

19         // 获取到request对象

20         HttpServletRequest request = (HttpServletRequest)pageContext.getRequest();

21         // 判断

22         String header = request.getHeader("referer");

23         if(header != null && header.startsWith(getSite())){

24             // 执行后续的页面

25             return Tag.EVAL_PAGE;

26         }else{

27             // 页面的重定向

28             HttpServletResponse response = (HttpServletResponse)pageContext.getResponse();

29             try {

30                 response.sendRedirect(getBack());

31             } catch (IOException e) {

32                 e.printStackTrace();

33             }

34             // 不执行

35             return Tag.SKIP_PAGE;

36         }

37     }

38 }

2. 描述文件

 1 <?xml version="1.0" encoding="UTF-8"?>

 2 <taglib

 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 http://java.sun.com/xml/ns/javaee/web-jsptaglibrary_2_1.xsd"

 6     version="2.1">

 7   <!-- 2. 编写标签库描述文件 -->

 8   <tlib-version>1.0</tlib-version>

 9   <short-name>jnb</short-name>

10    <tag>

11     <name>referer</name>

12     <tag-class>cn.itcast.custom.MyReferer</tag-class>

13     <body-content>empty</body-content>

14      <attribute>

15         <name>site</name>

16         <required>true</required>

17         <rtexprvalue>true</rtexprvalue>

18     </attribute>

19      <attribute>

20         <name>back</name>

21         <required>true</required>

22         <rtexprvalue>true</rtexprvalue>

23     </attribute>

24   </tag>

25 </taglib>    

3. 引入和使用

1 <%@taglib uri="/WEB-INF/referer.tld" prefix="my"%>

2    <my:referer site=http://localhost:8080/day11/list.jsp

3  back="/day11/list.jsp"/>

实现一个基本防盗链标签,布布扣,bubuko.com