SecurityManager StackOverflowError

Question

運行以下代碼，getPackage（）行出現StackOverflowError錯誤。 如果我不能訪問getPackage（）來檢查包，我該如何授予對包內類的權限？

package myPkg.security; 

import java.security.Permission; 

import javax.swing.JOptionPane; 

public class SimpleSecurityManager extends SecurityManager { 

    @Override 
    public void checkPermission(Permission perm) { 
Class<?>[] contextArray = getClassContext(); 
for (Class<?> c : contextArray) { 
    checkPermission(perm, c); 
} 
    } 

    @Override 
    public void checkPermission(Permission perm, Object context) { 
if (context instanceof Class) { 
    Class clazz = (Class) context; 
    Package pkg = clazz.getPackage(); // StackOverflowError 
    String name = pkg.getName(); 
    if (name.startsWith("java.")) { 
    // permission granted 
    return; 
    } 
    if (name.startsWith("sun.")) { 
    // permission granted 
    return; 
    } 
    if (name.startsWith("myPkg.")) { 
    // permission granted 
    return; 
    } 
} 
// permission denied 
throw new SecurityException("Permission denied for " + context); 
    } 

    public static void main(String[] args) { 
System.setSecurityManager(new SimpleSecurityManager()); 
JOptionPane.showMessageDialog(null, "test"); 
    } 

} 

Answer 1

解決！只需添加到開始第一次checkPermission方法的：

if (perm instanceof FilePermission) { 
    if (perm.getActions().equals("read")) { 
    // grant permission 
    return; 
    } 
} 

Answer 2

如果你只是想限制的包，怎麼樣實現checkPackageAccess和/或checkPackageDefinition，而不是通用的checkPermission？