使用redis实现session共享
使用redis实现session共享
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继上一遍文章,使用nginx实现负载均衡以后,新的问题又产生了,当使用负载均衡以后,我们如何实现session共享,因为session是保存在服务端的,对于单体应用来说这不是问题,因为只有一个服务器,但是在多个服务器的情况下,我们在A服务器登陆成功,session存在A服务器,下一次请求被转发到了B,但是B服务器中没有对应的用户信息,重新让用户登录肯定不合适,这个时候我们需要将该session信息放在一个公共的地方,不管后续请求被转发到了哪个服务器,我们都去从公共的位置去取,这样就实现了session共享(类似问题的解决方案有很多,比如存入数据库、配置tomcat实现session同步,使用jwt等等),今天我们使用的是spring session+redis来实现.
此处的代码基于上一篇的nginx实现负载均衡
改造而来。
1.pom文件引入相关依赖(这是我全部的依赖,贴出来方便复制粘贴)
<?xml version="1.0" encoding="UTF-8"?>
<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 https://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>2.7.1</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.weige</groupId>
<artifactId>test-db-nginx</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>test-db-nginx</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.2.2</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.2.1</version>
</dependency>
<!-- 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>
<version>2.6.4</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.springframework.session/spring-session-data-redis -->
<dependency>
<groupId>org.springframework.session</groupId>
<artifactId>spring-session-data-redis</artifactId>
<version>2.6.3</version>
</dependency>
</dependencies>
<build>
<finalName>bookTest86</finalName>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
2.配置redis相关信息
spring.redis.host=127.0.0.1
spring.redis.port=6380
spring.redis.password=123456
3.添加一个配置类
package com.weige.config;
import org.springframework.context.annotation.Configuration;
import org.springframework.session.data.redis.config.annotation.web.http.EnableRedisHttpSession;
/**
* Created with IntelliJ IDEA.
*
* @Author: weige
* @Date: 2022/07/13/19:41
* @Description:
*/
@Configuration
@EnableRedisHttpSession(maxInactiveIntervalInSeconds = 70)//session过期时间,单位为秒
public class RedisSessionConfig {
}
4.添加一个模拟用户登录/注销的接口
package com.weige.controller;
import com.weige.entity.User;
import com.weige.vo.RespBean;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
/**
* Created with IntelliJ IDEA.
*
* @Author: weige
* @Date: 2022/07/13/7:59
* @Description:
*/
@RestController
public class UserController {
@Value("${server.port}")
private String port;
//登录
@PostMapping("/login")
public RespBean login( HttpServletRequest request){
HttpSession session=request.getSession();
//获取当前的sessionId
String sessionId = session.getId();
//懒得传入,在这里写死的,能说明问题就行
User user=new User();
user.setUsername("悟空");
user.setPassword("123456");
user.setAddress("北京市天安门");
System.out.println("登陆成功,sessionId:"+sessionId+";user===>"+user);
session.setAttribute(sessionId,user);
return RespBean.ok("登陆成功:"+port,user);
}
//获取当前用户
@GetMapping("/getuser")
public RespBean getuser(HttpServletRequest request){
HttpSession session=request.getSession();
String sessionId = session.getId();
System.out.println("获取用户,sessionId==>"+sessionId);
return RespBean.ok("登陆成功:"+port,session.getAttribute(sessionId));
}
//注销
@GetMapping("/logout")
public RespBean loginout(String username, HttpServletRequest request){
HttpSession session=request.getSession();
//这里不做查询,直接清除session
String sessionId = session.getId();
System.out.println("注销登录,sessionId==>"+sessionId+"服务端口:"+port);
session.removeAttribute(sessionId);
return RespBean.ok("注销成功:"+port);
}
}
5.改造获取数据的接口,添加了对用户是否登录的判断
package com.weige.controller;
import com.weige.entity.Book;
import com.weige.entity.User;
import com.weige.service.BookService;
import com.weige.vo.RespBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.util.List;
/**
* Created with IntelliJ IDEA.
*
* @Author: weige
* @Date: 2022/07/11/20:57
* @Description:
*/
@RestController
@RequestMapping("/book")
public class BookController {
@Autowired
BookService bookService;
@Value("${server.port}")
private String port;
@GetMapping("/")
public RespBean getAllBooks(HttpSession session){
//HttpSession session=request.getSession();
String sessionId = session.getId();
System.out.println("查询book,sessionId==>"+sessionId+"服务端口:"+port);
User user= ((User) session.getAttribute(sessionId));
if(user==null){
return RespBean.error("用户还没登录,请先登录!服务端口:"+port);
}
System.out.println("我从session中拿到了User--->"+user );
List<Book> books=bookService.getAllBooks();
return RespBean.ok(port,books);
}
@PostMapping("/")
public RespBean addBook(@RequestBody Book book){
int ret=bookService.addBook(book);
return RespBean.ok(port,ret);
}
@PutMapping("/")
public RespBean updateBook(@RequestBody Book book){
int ret=bookService.updateBook(book);
return RespBean.ok(port,ret);
}
@DeleteMapping("/{id}")
public RespBean delBook(@PathVariable Integer id){
int ret=bookService.delBook(id);
return RespBean.ok(port,ret);
}
}
关键的信息就是这些,在获取全部book信息的时候,会根据sessionId,从当前session中获取用户信息,如果用户不存在,就提示没有登录,登录后可以正常获取,我们将项目打包,放在服务器上,以8886和8887端口启动,结合之前配置的nginx负载均衡,我们希望无论在那一台服务上登录过,都可以正常的获取book信息,这样我们session共享的需求就实现了
(1)启动8886
(2)启动8887
(3)请求获取book接口,提示未登录,此时提供服务的是8886
(4)请求登录接口,注意此时提供服务的是8887,多次请求,8886和8887会交替出现,这是因为我们在nginx中配置的权重
(5)再次请求获取book接口(此时提供服务的是8886)
以上说明,同一个session,我们从任意一台服务器登陆成功后,在其它服务器上都可以获取到session中的用户信息,实现了session共享。
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