【分布式-session】spring boot + redis 实现session共享

1 为何需要Session共享？

因为每个应用容器默认是将Session存储在本地内存，仅容器本身可以访问，但是在分布式集群中，包含多个应用容器，一个用户请求会随机发送到容器上，比如，用户在A容器登陆，登陆后又访问B容器，那咋办呢？方案就是：Session共享。

2 方案样例：springboot + redis

安装redis可参考：https://blog.csdn.net/qqchaozai/article/details/100119944

springboot环境搭建可参考：https://blog.csdn.net/qqchaozai/article/details/82355175

先在pom.xml中引入依赖库

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.0.2.RELEASE</version>
	</parent>
	<groupId>com.web.spring</groupId>
	<artifactId>cluster2</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>cluster</name>
	<url>http://maven.apache.org</url>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	</properties>

	<dependencies>
		<!-- web -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<!-- redis -->
		<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-data-redis -->
		<dependency>
		    <groupId>org.springframework.boot</groupId>
		    <artifactId>spring-boot-starter-data-redis</artifactId>
		</dependency>

		<!-- Spring session -->
		<dependency>
			<groupId>org.springframework.session</groupId>
			<artifactId>spring-session-data-redis</artifactId>
		</dependency>
	</dependencies>
</project>

application.properties配置redis

#####################server######################
server.port=8000
server.tomcat.uriEncoding=utf-8
#####################redis######################
redis.database=local 
redis.host=127.0.0.1 
redis.password= 
redis.port=6379

启动类+测试Controller

@SpringBootApplication
@EnableRedisHttpSession
public class App 
{
    public static void main( String[] args )
    {
        SpringApplication.run(App.class, args);
    }
}

/**
 * 用于测试共享Session数据访问
 * 
 * @author chaozai
 * @date 2019年8月28日
 *
 */
@RestController
public class SessionController {
    /**
     * 登陆时，将当前登陆IP记录到session中
     * 
     * @param request
     * @return
     */
    @GetMapping("/login")
    public Map<String, Object> setUrl(HttpServletRequest request) {
	request.getSession().setAttribute("address", request.getRemoteAddr());
	Map<String, Object> map = new HashMap<>();
	map.put("address",  request.getRemoteAddr());
	return map;
    }
    /**
     * 获取当前session内容
     * 
     * @param request
     * @return
     */
    @GetMapping("/getSession")
    public Map<String, Object> getSession(HttpServletRequest request) {
	Map<String, Object> map = new HashMap<>();
	map.put("sessionId", request.getSession().getId());
	map.put("address", request.getSession().getAttribute("address"));
	return map;
    }
}

负责一份工程，重命名，修改新端口号为8001，启动两个工程，测试：