fix readme

Author: JoyChou93

README.md

@@ -20,7 +20,7 @@
 - [SQL注入](https://github.com/JoyChou93/java-sec-code/blob/master/src/main/java/org/joychou/controller/SQLI.java)
 - [URL白名单Bypass](https://github.com/JoyChou93/java-sec-code/blob/master/src/main/java/org/joychou/controller/URLWhiteList.java)
 - [Java RMI](https://github.com/JoyChou93/java-sec-code/blob/master/src/main/java/org/joychou/RMI/Server.java)
-- [Fastjson](https://github.com/JoyChou93/java-sec-code/blob/master/src/main/java/org/joychou/RMI/Fastjson.java)
+- [Fastjson](https://github.com/JoyChou93/java-sec-code/blob/master/src/main/java/org/joychou/controller/Fastjson.java)
 
 
 ## 漏洞说明