improve WallFilter

src/main/java/com/alibaba/druid/wall/WallFilter.java

@@ -313,6 +313,10 @@ public class WallFilter extends FilterAdapter implements WallFilterMBean {
     
     @Override
     public boolean isWrapperFor(FilterChain chain, Wrapper wrapper, Class<?> iface) throws SQLException {
+        if (config.isAllowDoPrivileged() && WallProvider.ispPivileged()) {
+            return chain.isWrapperFor(wrapper, iface);
+        }
+        
         if (!this.provider.getConfig().isWrapAllow()) {
             return false;
         }
@@ -321,6 +325,10 @@ public class WallFilter extends FilterAdapter implements WallFilterMBean {
 
     @Override
     public <T> T unwrap(FilterChain chain, Wrapper wrapper, Class<T> iface) throws SQLException {
+        if (config.isAllowDoPrivileged() && WallProvider.ispPivileged()) {
+            return chain.unwrap(wrapper, iface);
+        }
+        
         if (!this.provider.getConfig().isWrapAllow()) {
             return null;
         }

src/main/java/com/alibaba/druid/wall/WallProvider.java

@@ -176,6 +176,15 @@ public abstract class WallProvider {
         result.getViolations().addAll(visitor.getViolations());
         return result;
     }
+    
+    public static boolean ispPivileged() {
+        Boolean value = privileged.get();
+        if (value == null) {
+            return false;
+        }
+        
+        return value.booleanValue();
+    }
 
     public static <T> T doPrivileged(PrivilegedAction<T> action) {
         privileged.set(Boolean.TRUE);