fix support list for JSONPathSingleName, for issue #3331

core/src/main/java/com/alibaba/fastjson2/JSONPathSingleName.java

@@ -115,6 +115,11 @@ final class JSONPathSingleName
             return ((Map) root).containsKey(name);
         }
 
+        if (root instanceof List) {
+            List list = (List) root;
+            return !list.isEmpty() && contains(list.get(0));
+        }
+
         ObjectWriterProvider provider = getWriterContext().provider;
 
         ObjectWriter objectWriter = provider.getObjectWriter(root.getClass());

core/src/test/java/com/alibaba/fastjson2/issues_3300/Issue3331.java

@@ -0,0 +1,18 @@
+package com.alibaba.fastjson2.issues_3300;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class Issue3331 {
+    @Test
+    public void test() {
+        String json = "[{\"priority_flag\":9,\"service_type\":\"bbb\",\"destination_addr\":\"bbb\"}]";
+        Object object1 = com.alibaba.fastjson.JSON.parse(json);
+        Object object2 = com.alibaba.fastjson2.JSON.parse(json);
+        String path = "$.service_type";
+        assertEquals(com.alibaba.fastjson.JSONPath.contains(object1, path), com.alibaba.fastjson2.JSONPath.contains(object2, path));
+        path = "$[0].service_type";
+        assertEquals(com.alibaba.fastjson.JSONPath.contains(object1, path), com.alibaba.fastjson2.JSONPath.contains(object2, path));
+    }
+}