MuleSoft Anypoint Studio 连接 Sap hana 配置问题

Question

Anypoint Studio 画布中有三个组件.
1.HttpListener配置如下:

Protocol: HTTP(Default)
Host: All Interfaces[0.0.0.0](default)
Port: 8081

2.Select配置连接HANA正确,测试通过.

SELECT TOP 100 * FROM SAPHANADB.KFC;  //测试SQL

3.Transform Message默认配置如下:

%dw 2.0
output application/java
---
{}

访问接口返回信息如下:

java.lang.RuntimeException: Attempted to send invalid data through http response.

尝试过将java改为json,将{}改为payload,同样返回如上信息.

%dw 2.0
output application/json
---
payload

请问如何配置?