利用Redis同步spring-session

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原理：

第一次创建session，往redis里缓存备份一份
第二次，先从session里面找，找不到的话在往redis里面找

注：

在springboot项目里能很好的支持，如果自己写的话，还需要过滤器等很麻烦

接入流程：

1、引入依赖

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.3.3.RELEASE</version>
    </parent>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--spring boot 与redis应用基本环境配置 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-redis</artifactId>
        </dependency>
        <!--spring session 与redis应用基本环境配置,需要开启redis后才可以使用，不然启动Spring boot会报错 -->
        <dependency>
            <groupId>org.springframework.session</groupId>
            <artifactId>spring-session-data-redis</artifactId>
        </dependency>

    </dependencies>

2、加入代码

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.session.data.redis.config.annotation.web.http.EnableRedisHttpSession;

//这个类用配置redis服务器的连接
//maxInactiveIntervalInSeconds为SpringSession的过期时间（单位：秒）
@EnableRedisHttpSession(maxInactiveIntervalInSeconds = 1800)
public class SessionConfig {

    // 冒号后的值为没有配置文件时，制动装载的默认值
    @Value("${redis.hostname:localhost}")
    String HostName;
    @Value("${redis.port:6379}")
    int Port;

    @Bean
    public JedisConnectionFactory connectionFactory() {
        JedisConnectionFactory connection = new JedisConnectionFactory();
        connection.setPort(Port);
        connection.setHostName(HostName);
        return connection;
    }
}


import org.springframework.session.web.context.AbstractHttpSessionApplicationInitializer;
//初始化Session配置
public class SessionInitializer extends AbstractHttpSessionApplicationInitializer {
    public SessionInitializer() {
        super(SessionConfig.class);
    }
}

3、session使用没啥区别

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

import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class IndexController {


    @Value("${server.port}")
    private String port;

    @RequestMapping("/index")
    public String index() {
        return "server---value:" + port;
    }

    @RequestMapping("/setSession")
    public String setSession(HttpServletRequest request, String key, String value) {
        HttpSession session = request.getSession();
        session.setAttribute(key, value);
        return "server---port:" + port + ",success";
    }

    @RequestMapping("/getSession")
    public String getSession(HttpServletRequest request, String key) {
        HttpSession session = null;
        try {
            session = request.getSession(false);
        } catch (Exception e) {
            // TODO: handle exception
        }
        String value = null;
        if (session != null) {
            value = (String) session.getAttribute(key);
        }

        return "server---port:" + port + "  value:" + value;
    }
}