轉自 http://blog.csdn.net/yang_net/article/details/5740354
使用applet遇到java.security.AccessControlException異常
寫Applet與Servlet的HTTP通信時報錯java.security.AccessControlException: access denied，轉載博客內容如下：
今天寫一個使用jta（Telnet/SSH for the JAVA） applet例子， 遇到Socket: can't connect: java.security.AccessControlException: access denied (java.net.SocketPermission 127.0.0.1:23 connect,resolve)。
例子jtaAppletView.html 內容爲：
<html>
<body>
<applet CODEBASE="."
ARCHIVE="jta26.jar"
CODE="de.mud.jta.Applet"
WIDTH=590 HEIGHT=360>
<param name="Socket.port" value="23">
<param name="Socket.host" value="127.0.0.1">
</applet>
</body>
</html>
解決方法：
在jre的lib/security/java.policy中的default permissions grant 增加一行permission java.net.SocketPermission "*", "accept, connect, listen, resolve";
部分內容如下：
// Standard extensions get all permissions by default
grant codeBase "file:${{java.ext.dirs}}/*" {
permission java.security.AllPermission;
};
// default permissions granted to all domains
grant {
permission java.net.SocketPermission "*", "accept, connect, listen, resolve";
.......
};
學習參考：
http://www.cs.fit.edu/~ryan/java/language/security.html
http://download.oracle.com/docs/cd/E17409_01/javase/tutorial/security/index.html