feat: support ssti and expression packer

vul-webapp/src/main/java/OgnlServlet.java

@@ -0,0 +1,28 @@
+import ognl.Ognl;
+import ognl.OgnlContext;
+import ognl.OgnlException;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+/**
+ * @author ReaJason
+ * @since 2024/12/14
+ */
+public class OgnlServlet extends HttpServlet {
+    @Override
+    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+        String data = req.getParameter("data");
+        OgnlContext context = new OgnlContext();
+        Object value = null;
+        try {
+            value = Ognl.getValue(data, context, context.getRoot());
+        } catch (OgnlException e) {
+            throw new RuntimeException(e);
+        }
+        resp.getWriter().println(value);
+    }
+}