访问被拒绝（“java.util.PropertyPermission”“user.name”“read”）Java Applet for 1.8.0_25 version

Question

我有这个小程序：

import java.applet.Applet;

public class UserNapplet extends Applet {
public void init() { }
public String getUser() {
    try {
    return System.getProperty("user.name");
    } catch (Exception e) {
    e.printStackTrace();
    return "error";
    }
}
}

和html标签：

<div id="aple"><applet code="UserNapplet.class" height="0" width="0" id="uname" archive="UserNapplet.jar"/></div>` 

如何让它发挥作用？

我做了什么？ 一个蝙蝠文件.....

del UserNapplet.jar
del UserNapplet.class
javac UserNapplet.java
jar cvf UserNapplet.jar UserNapplet.class
jar ufm UserNapplet.jar mymanifest.txt
jarsigner -verbose UserNapplet.jar SecGen 

//（SecGen是我的＆＃34;证书＆＃34;）...

mymanifest.txt说：

Permissions: all-permissions
Application-Name: SecGen
Codebase: http://172.31.31.4/MyAppDir `  (a folder in C.\inetpub\wwwroot)

正在运行的policytools生成

/* AUTOMATICALLY GENERATED ON Wed Dec 10 08:29:52 PYST 2014*/    
/* DO NOT EDIT */    
grant codeBase "file:///C:/inetpub/wwwroot/MyAppDir/UserNapplet.jar" {
permission java.security.AllPermission;
permission java.util.PropertyPermission "*", "read";
};

所有这些....小程序仍在抛出

java.security.accesscontrolexception: access denied ("java.util.propertypermission" "user.name" "read")

还有什么可做的？