spring synchronizeOnSession example

to run this synchronizeOnSession example:

- set adapter.setSynchronizeOnSession(true) in MyPostProcessor
- run http://localhost:8080/sleep
- run http://localhost:8080/xxx
- then `xxx` will wait for `sleep` wake up!

or test the synchronizeOnSession = false

- set adapter.setSynchronizeOnSession(false) in MyPostProcessor
- run http://localhost:8080/sleep
- run http://localhost:8080/xxx
- then `xxx` will **NOT** wait for `sleep` wake up!

```java:DemoApplication.java
package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.ImportResource;

@SpringBootApplication
@Configuration
@ImportResource("servlet-context.xml")
public class DemoApplication {

	public static void main(String[] args) {
		SpringApplication.run(DemoApplication.class, args);
	}
}

```
```java:HelloWorldController.java
package com.example.demo;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.apache.tomcat.util.http.parser.Cookie;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 *  * Spring Boot HelloWorld.  synchronizeOnSession example
 */
@RestController
public class HelloWorldController {
	@RequestMapping(value = "/{param}")
	public String sayHello(@PathVariable String param, HttpServletRequest request, HttpSession session) {
		System.out.println("param=" + param);

		Object id = session.getId();
		if (id == null) {
			System.out.println("session not exist " + id);
			//session.setAttribute("p", p);
		} else {
			System.out.println("session existed ，id=" + id);
			if (param.equals("sleep")) {
				try {
					Thread.sleep(15000);
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
				System.out.println("wake up!");
			}
		}
		return "Hello,World! " + param;
	}
}

```
```java:MyPostProcessor.java
package com.example.demo;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;

@Component
public class MyPostProcessor implements BeanPostProcessor {
	@Override
	public Object postProcessBeforeInitialization(Object bean, String name) throws BeansException {
		if (bean instanceof RequestMappingHandlerAdapter) {
			RequestMappingHandlerAdapter adapter = (RequestMappingHandlerAdapter) bean;
			adapter.setSynchronizeOnSession(true);
		}

		return bean;
	}

	@Override
	public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
		return bean;
	}
}

```
```xml:servlet-context.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
	<context:property-placeholder
		location="classpath:*.properties" />
	<context:component-scan
		base-package="com.example.demo.MyPostProcessor" />

</beans>
```
details ref: https://github.com/siumennel/demo
https://dzone.com/articles/creating-a-spring-boot-project-with-eclipse-and-ma