Seckill system 2 redis solves the problem of distributed session

Preface

If you operate on one Tomcat On , There is no problem , But when we deploy multiple systems , coordination Nginx There will be a problem of user login .

reason

because Nginx Use a load balancing policy , Distribute the request to the backend ,
in other words , stay Tomcat 1 After logging in , User information exists Tomcat1 Of Session in , The next request is coming Tomcat2 On , At this time Tomcat2 On Session There is no user information in , I'm going to log in .

solve

redis Installation tutorial self-study

Redis Implement distributed Session

Method 1、 Use SpringSession Realization （ This method can't jump to the page ）

1、 Add dependency ：

        <!-- spring data redis  rely on  -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>
        <!-- commons-pool2  Object pool dependency  -->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-pool2</artifactId>
        </dependency>
        <!-- spring-session  rely on  -->
        <dependency>
            <groupId>org.springframework.session</groupId>
            <artifactId>spring-session-data-redis</artifactId>
        </dependency>

2、 To configure Redis

spring:
  # thymeleaf Turn off caching 
  thymeleaf:
    cache: false

  # MySql Data source configuration 
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/secKill?useUnicode=true&characterEncoding=utf-8&useSSL=false
    username: root
    password: 123456

    #  Fastest connection pool 
    hikari:
      #  The name of the connection pool 
      pool-name: DateHikariCP
      #  Minimum number of idle connections 
      minimum-idle: 5
      #  Maximum free connection lifetime   Default 600000(10 minute )
      idle-timeout: 1800000
      #  maximum connection   Default 10
      maximum-pool-size: 10
      #  Connections returned from the connection pool are automatically submitted 
      auto-commit: true
      #  Maximum connection lifetime   0 For permanent survival , Default  1800000( minute )
      max-lifetime: 1800000
      #  Connection timeout   Default 30000(30 second )
      connection-timeout: 30000
      #  A query statement to test whether the connection is possible 
      connection-test-query: SELECT 1
  # Redis To configure 
  redis:
    host: 127.0.0.1
    port: 6379
    #  Database used  0
    database: 0
    #  Connection timeout 
    timeout: 10000ms
    lettuce:
      #  Configuration of connection pool 
      pool:
        #  maximum connection  8
        max-active: 8
        #  Maximum connection blocking time 
        max-wait: 10000ms
        #  Maximum free connection 
        max-idle: 200
        #  Minimum free connection 
        min-idle: 5


# mybatis-plus  To configure 
mybatis-plus:
  #  To configure  Mapper.xml The path of the mapping file 
  mapper-locations: classpath*:/mapper/*.xml # mybatis SQL  Print ( Interface method in package , No  mapper.xml The bag where it is ) logging: level: com.example.seckill.mapper: DEBUG 

This is the time Just OK 了 , After logging in ,Session It will be saved Redis - 0( library ) -spring Session in

here Comment out the

// /**
// *  After verifying the user successfully, generate  cookie, take cookie  Save with the user  session in 
// */
// //  Use UUID Generate  cookie
// String cookie = UUIDUtil.uuid();
// //  take  cookie  Save with the user  session  in 
// request.getSession().setAttribute(cookie,user);
// //  Set up  cookie
// CookieUtil.setCookie(request,response,"userCookie",cookie);

Log in again Discovery will also be saved Redis in .

Method 2、 Save user information in redis in

1、 Add dependency

<!-- spring data redis  rely on  -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>
        <!-- commons-pool2  Object pool dependency  -->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-pool2</artifactId>
        </dependency>

2、redis Configuration of And methods 1 equally
3、Redsi Configuration class

package com.example.seckill.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;


/** * Redis  To configure  */
@Configuration
public class RedisConfig {
    

    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {
    
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();

        //key serialize 
        redisTemplate.setKeySerializer(new StringRedisSerializer());
        //value serialize 
        redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer());
        //hash type value serialize 
        redisTemplate.setHashKeySerializer(new StringRedisSerializer());
        redisTemplate.setHashValueSerializer(new GenericJackson2JsonRedisSerializer());

        // Injection connection factory 
        redisTemplate.setConnectionFactory(redisConnectionFactory);
        return redisTemplate;
    }
}

4、json Tool class

This is very important , If not from redis From user The information does not match , I can't jump Product page

package com.example.seckill.util;

import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;
import java.util.List;

/** * Json Tool class  * * @author zhoubin * @since 1.0.0 */
public class JsonUtil {
    
    private static ObjectMapper objectMapper = new ObjectMapper();

    /** *  Converts an object to json character string  * * @param obj * @return */
    public static String object2JsonStr(Object obj) {
    
        try {
    
            return objectMapper.writeValueAsString(obj);
        } catch (JsonProcessingException e) {
    
            // Print exception information 
            e.printStackTrace();
        }
        return null;
    }

    /** *  Convert a string to an object  * * @param <T>  Generic  */
    public static <T> T jsonStr2Object(String jsonStr, Class<T> clazz) {
    
        try {
    
            return objectMapper.readValue(jsonStr.getBytes("UTF-8"), clazz);
        } catch (JsonParseException e) {
    
            e.printStackTrace();
        } catch (JsonMappingException e) {
    
            e.printStackTrace();
        } catch (IOException e) {
    
            e.printStackTrace();
        }
        return null;
    }

    /** *  take json Data to pojo object list * <p>Title: jsonToList</p> * <p>Description: </p> * * @param jsonStr * @param beanType * @return */
    public static <T> List<T> jsonToList(String jsonStr, Class<T> beanType) {
    
        JavaType javaType = objectMapper.getTypeFactory().constructParametricType(List.class, beanType);
        try {
    
            List<T> list = objectMapper.readValue(jsonStr, javaType);
            return list;
        } catch (Exception e) {
    
            e.printStackTrace();
        }

        return null;
    }
}

5、 modify UserServiceImpl Code

After verifying the user , take user Put in redis
And add through cookie obtain user Methods

package com.example.seckill.service.impl;

import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.seckill.common.RespBean;
import com.example.seckill.common.RespBeanEnum;
import com.example.seckill.controller.parm.LoginRequestParam;
import com.example.seckill.exception.GlobalException;
import com.example.seckill.mapper.UserMapper;
import com.example.seckill.pojo.User;
import com.example.seckill.service.IUserService;
import com.example.seckill.util.CookieUtil;
import com.example.seckill.util.JsonUtil;
import com.example.seckill.util.MD5Util;
import com.example.seckill.util.UUIDUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/** * <p> *  User table   Service implementation class  * </p> * * @author jobob * @since 2022-06-13 */
@Service
public class UserServiceImpl extends ServiceImpl<UserMapper, User> implements IUserService {
    
    @Autowired(required = false)
    UserMapper userMapper;

    @Autowired
    private RedisTemplate redisTemplate;


    @Override
    public RespBean doLogin(LoginRequestParam param, HttpServletRequest request, HttpServletResponse response) {
    
        String password = param.getPassword();
        String mobile = param.getMobile();

        User user = userMapper.selectById(mobile);
        if (null == user){
    
            throw new GlobalException(RespBeanEnum.LOGIN_ERROR);
        }

        if (!MD5Util.formPassToDBPass(password,user.getSalt()).equals(user.getPassword())){
    
            throw new GlobalException(RespBeanEnum.LOGIN_ERROR);
        }

        /** *  After verifying the user successfully, generate  cookie, take cookie  Save with the user  session in  */
        //  Use UUID Generate  cookie
        String cookie = UUIDUtil.uuid();
        //  take  cookie  Save with the user  session  in 
// request.getSession().setAttribute(cookie,user);
        redisTemplate.opsForValue().set("user:" + cookie, JsonUtil.object2JsonStr(user));

        //  Set up  cookie
        CookieUtil.setCookie(request,response,"userCookie",cookie);
        return RespBean.success(cookie);
    }

    @Override
    public User getUserByCookie(String cookie, HttpServletRequest request, HttpServletResponse response) {
    
        if (StringUtils.isEmpty(cookie)){
    
            return null;
        }
        String userJson = (String) redisTemplate.opsForValue().get("user:" + cookie);
        User user = JsonUtil.jsonStr2Object(userJson, User.class);
        if (null != user){
    
            //  Set up  cookie
            CookieUtil.setCookie(request,response,"userCookie",cookie);
        }
        return user;
    }
}

6、 goods Controller

package com.example.seckill.controller;

import com.example.seckill.common.RespBean;
import com.example.seckill.controller.parm.LoginRequestParam;
import com.example.seckill.pojo.User;
import com.example.seckill.service.IGoodsService;
import com.example.seckill.service.IUserService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.CookieValue;
import org.springframework.web.bind.annotation.RequestMapping;

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


@RequestMapping("/goods")
@Controller
@Slf4j
public class GoodsController {
    

    @Autowired
    IGoodsService goodsService;

    @Autowired
    IUserService userService;

    /** *  Jump to product page  * @param * @param model * @param cookie * @return */
    @RequestMapping("/toList")
    public String toList(HttpServletRequest request, HttpServletResponse response, Model model, @CookieValue("userCookie") String cookie){
    

        if (StringUtils.isEmpty(cookie)){
     // If  cookie by   empty   Jump to   The login page 
            return "login";

        }
        //  from session  Get users 
// User user = (User) session.getAttribute(cookie);
        User user = userService.getUserByCookie(cookie, request, response);

        if (null == user){
     //  If the user information is empty   Jump to login 
            return "login";
        }
        //  Put user information   To the front page 
        model.addAttribute("user",user);
        return "goodsList";

    }

}

Avoid completing each interface above according to Cookie obtain User Information , Avoid code redundancy , Special optimization ：
1、UserArgumentResolvers class

package com.example.seckill.config;

import com.example.seckill.pojo.User;
import com.example.seckill.service.IUserService;
import com.example.seckill.util.CookieUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.MethodParameter;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.support.WebDataBinderFactory;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.ModelAndViewContainer;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/** *  Custom user parameters  */
@Component
public class UserArgumentResolvers implements HandlerMethodArgumentResolver {
    

    @Autowired
    IUserService userService;

    @Override
    public boolean supportsParameter(MethodParameter parameter) {
    
        Class<?> parameterType = parameter.getParameterType();


        return parameterType == User.class;
    }

    @Override
    public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception {
    

        HttpServletRequest request = webRequest.getNativeRequest(HttpServletRequest.class);
        HttpServletResponse response = webRequest.getNativeResponse(HttpServletResponse.class);

        String cookie = "486ceb27176a485f85e3c3d1f4f35e77";
// String cookie = CookieUtil.getCookieValue(request, "userCookie");
        if (StringUtils.isEmpty(cookie)){
     // If  cookie by   empty   Jump to   The login page 
            return null;

        }
        return userService.getUserByCookie(cookie, request, response);

    }
}

2、

package com.example.seckill.config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import java.util.List;

/** * MVC Configuration class  * */
@Configuration
//@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {
    

    @Autowired
    UserArgumentResolvers userArgumentResolvers;
    @Override
    public void addArgumentResolvers(List<HandlerMethodArgumentResolver> resolvers){
    
        resolvers.add(userArgumentResolvers);
    }
}

3、goodController

package com.example.seckill.controller;

import com.example.seckill.common.RespBean;
import com.example.seckill.controller.parm.LoginRequestParam;
import com.example.seckill.pojo.User;
import com.example.seckill.service.IGoodsService;
import com.example.seckill.service.IUserService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.CookieValue;
import org.springframework.web.bind.annotation.RequestMapping;

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


@RequestMapping("/goods")
@Controller
@Slf4j
public class GoodsController {
    

    @Autowired
    IGoodsService goodsService;

    @Autowired
    IUserService userService;

    /** *  Jump to product page  * @param * @param model * @param * @return */
    @RequestMapping("/toList")
    public String toList(Model model,User user){
    
        //  Put user information   To the front page 
        model.addAttribute("user",user);
        return "goodsList";

    }

}

problem ： Here I have a problem , Each generation Cookie Put in Redis It's normal , But call other interfaces after successful login adopt CookieUtil Acquired Cookie Not generated by this login Cookie It's annoying ~ I don't know much about this So I'm making sure that redis There is this cookie , take cookie It's dead