[bug](json)Fix the problem of be down caused by json path ending with \ (#28180)

be/src/vec/functions/function_json.cpp

@@ -229,12 +229,19 @@ rapidjson::Value* get_json_object(std::string_view json_string, std::string_view
     std::vector<JsonPath>* parsed_paths;
     std::vector<JsonPath> tmp_parsed_paths;
 
+    //Cannot use '\' as the last character, return NULL
+    if (path_string.back() == '\\') {
+        document->SetNull();
+        return document;
+    }
+
 #ifdef USE_LIBCPP
     std::string s(path_string);
     auto tok = get_json_token(s);
 #else
     auto tok = get_json_token(path_string);
 #endif
+
     std::vector<std::string> paths(tok.begin(), tok.end());
     get_parsed_paths(paths, &tmp_parsed_paths);
     if (tmp_parsed_paths.empty()) {