Nginx可以做四层、七层反向代理，主要原理是对下游客户端、上游应用间分别建立独立的连接（或者UDP会话），将消息基于协议、规则转换后，基于上游负载均衡算法，进行消息转发。

LOG如下：偶数次是超时。

Hello and welcome!

test-->

--->

0:{"user": "demo1","age": 1}

--1->

--2: 200

--3:: [POST] test!

--5->

disconnect()

return :[POST] test!

--->

1:{"user": "demo1","age": 2}

--1->

java.net.SocketTimeoutException: Read timed out

disconnect()

return :java.net.SocketTimeoutException: Read timed out

--->

2:{"user": "demo1","age": 3}

--1->

--2: 200

--3:: [POST] test!

--5->

disconnect()

return :[POST] test!

--->

3:{"user": "demo1","age": 4}

--1->

java.net.SocketTimeoutException: Read timed out

disconnect()

return :java.net.SocketTimeoutException: Read timed out

--->

4:{"user": "demo1","age": 5}

--1->

--2: 200

--3:: [POST] test!

--5->

disconnect()

return :[POST] test!

--->

5:{"user": "demo1","age": 6}

--1->

java.net.SocketTimeoutException: Read timed out

disconnect()

return :java.net.SocketTimeoutException: Read timed out

Process finished with exit code 0