我正在尝试了解java安全性和AccessController.doPrivileged()用法的基础知识我从一个示例程序开始importjava.security.AccessController;importjava.security.PrivilegedAction;publicclassAccessSystemProperty{publicstaticvoidmain(String[]args){System.out.println(System.getSecurityManager());AccessController.doPrivileged(newPrivilegedA

我正在尝试了解java安全性和AccessController.doPrivileged()用法的基础知识我从一个示例程序开始importjava.security.AccessController;importjava.security.PrivilegedAction;publicclassAccessSystemProperty{publicstaticvoidmain(String[]args){System.out.println(System.getSecurityManager());AccessController.doPrivileged(newPrivilegedA