中国加油，武汉加油！

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案例准备

本案例基于springboot篇】二十一. 基于springboot电商项目七 springboot整合Redis

1. 项目准备

1.1 shop-temp新建springboot-redis-user（module-maven）

Spring Boot DevTools
Lombok
Spring Web
Thymeleaf
MyBatis Framework
Spring Data Redis(Access+Driver)

1.2 导相关依赖

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>2.3</version>
</dependency>
<dependency>
	<groupId>com.wpj</groupId>
	<artifactId>base</artifactId>
	<version>1.0-SNAPSHOT</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.48</version>
</dependency>

1.3 编写User

package com.wpj.entity;

import com.baomidou.mybatisplus.annotations.TableId;
import com.baomidou.mybatisplus.annotations.TableName;
import com.baomidou.mybatisplus.enums.IdType;
import lombok.Data;

import java.io.Serializable;

@Data
@TableName("t_user")
public class User implements Serializable {
    @TableId(type = IdType.AUTO)
    private Integer id;
    private String username;
    private String password;
}

1.4 编写Mapper接口

package com.wpj.mapper;

import com.baomidou.mybatisplus.mapper.BaseMapper;
import com.wpj.entity.User;

public interface IUserMapper extends BaseMapper<User> {
}

1.5 编写Service及其impl

package com.wpj.service;

import com.wpj.entity.User;

public interface IUserService extends IBaseService<User> {
}

package com.wpj.service.impl;

import com.baomidou.mybatisplus.mapper.BaseMapper;
import com.wpj.entity.User;
import com.wpj.mapper.IUserMapper;
import com.wpj.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class UserServiceImpl extends BaseServiceImpl<User> implements IUserService {

    @Autowired
    private IUserMapper userMapper;

    @Override
    public BaseMapper<User> getMapper() {
        return userMapper;
    }
}

1.6 编写Controller

package com.wpj.controller;

import com.wpj.entity.User;
import com.wpj.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;

import java.util.List;

@Controller
public class UserController {
    @Autowired
    private IUserService userService;

    @RequestMapping(value = "/getUserList")
    public String getUserList(ModelMap map){
        List<User> list = userService.getList();
        map.put("list", list);
        return "userList";
    }

    @RequestMapping(value = "/addUser")
    public String addUser(){
        User user = new User();
        user.setUsername("admin");
        user.setPassword("123");
        userService.insert(user);
        return "redirect:getUserList";
    }


    @RequestMapping(value = "/deleteUser/{id}")
    public String deleteUser(@PathVariable Integer id){
        userService.deleteById(id);
        return "redirect:../getUserList";
    }

    @RequestMapping(value = "/updateUser")
    public String updateUser(User user){
        userService.update(user);
        return "redirect:getUserList";
    }

    @RequestMapping(value = "/getUserById/{id}")
    public String getUserById(@PathVariable Integer id,ModelMap map){
        User user = userService.selectById(id);
        map.put("user",user);
        return "updateUser";
    }

}

1.7 编写程序入口

package com.wpj;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication(scanBasePackages = "com.wpj")
@MapperScan(basePackages = "com.wpj.mapper")
public class SpringbootRedisUserApplication {
    public static void main(String[] args) {
        SpringApplication.run(SpringbootRedisUserApplication.class, args);
    }
}

1.8 编写yml

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/nz1904-springboot-shop
    username: root
    password: 123456
    driver-class-name: com.mysql.jdbc.Driver
mybatis-plus:
  type-aliases-package: com.wpj.entity

1.9 编写页面

1.10 启动程序入口

2. Redis做为缓存服务的使用

2.1 配置yml


spring:
  datasource:
    url: jdbc:mysql://localhost:3306/nz1904-springboot-shop
    username: root
    password: 123456
    driver-class-name: com.mysql.jdbc.Driver
  redis:
    host: 192.168.59.100
    password: admin

mybatis-plus:
  type-aliases-package: com.wpj.entity

2.2 Impl重写getList

@Autowired
private RedisTemplate redisTemplate;

@Override
public List<User> getList() {
    redisTemplate.setKeySerializer(new StringRedisSerializer());
    System.out.println("UserServiceImpl.getList");
    // 准备一个集合
    List<User> userList = null;
    // 先去缓存中查询，如果有直接返回，没有再到数据库中查询
    userList = (List<User>) redisTemplate.opsForValue().get("userList");
    if (userList == null) {
        // 双重锁机制来解决重复查询的问题，在单体架构中有效
        synchronized (this){
            if (userList == null) {
                System.out.println("进入数据库中查询");
                // 缓存没有，到数据库中
                userList = userMapper.selectList(null);
                // 把结果放入缓存中
                redisTemplate.opsForValue().set("userList", userList, 30, TimeUnit.SECONDS);
            }
        }
    }
    return userList;
}
@Override
public int deleteById(Integer id) {
    int i = super.deleteById(id);
    redisTemplate.delete("userList");
    return i;
}

2.3 改进

@Override
public List<User> getList() {
    redisTemplate.setKeySerializer(new StringRedisSerializer());
    List<User> userList = null;
    userList = (List<User>) redisTemplate.opsForValue().get("userList");

    if(userList == null) {
        // 先获取锁
        try {
            boolean lock = redisTemplate.opsForValue().setIfAbsent("lock", "true", 30,TimeUnit.SECONDS);
            if(lock) {
                // 获取了锁
                userList = userMapper.selectList(null);
                System.out.println("查询数据库。。");
                // 缓存的重建
                redisTemplate.opsForValue().set("userList", userList, 30, TimeUnit.SECONDS);
                // 释放锁
                redisTemplate.delete("lock");
            } else {
                // 休眠一会
                Thread.sleep(50);
                return getList();
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    return userList;
}

2.4 注解改进

2.4.1 导入相关依赖

<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-cache</artifactId>
   <version>2.1.5.RELEASE</version>
</dependency>

2.4.2 修改程序入口

package com.wpj;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;

@SpringBootApplication(scanBasePackages = "com.wpj")
@MapperScan(basePackages = "com.wpj.mapper")
@EnableCaching // 开启注解缓存
public class SpringbootRedisUserApplication {
    public static void main(String[] args) {
        SpringApplication.run(SpringbootRedisUserApplication.class, args);
    }
}

2.4.3 配置yml


spring:
  datasource:
    url: jdbc:mysql://localhost:3306/nz1904-springboot-shop
    username: root
    password: 123456
    driver-class-name: com.mysql.jdbc.Driver
  redis:
    host: 192.168.59.100
    password: admin
  cache:
    type: redis
mybatis-plus:
  type-aliases-package: com.wpj.entity

2.4.4 Impl

package com.wpj.service.impl;

import com.baomidou.mybatisplus.mapper.BaseMapper;
import com.wpj.entity.User;
import com.wpj.mapper.IUserMapper;
import com.wpj.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.CachePut;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.cache.annotation.Caching;
import org.springframework.context.annotation.Primary;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import org.springframework.stereotype.Service;

import java.io.UnsupportedEncodingException;
import java.util.List;
import java.util.concurrent.TimeUnit;

@Service
@Primary
public class UserServiceImpl extends BaseServiceImpl<User> implements IUserService {

    @Autowired
    private IUserMapper userMapper;

    @Override
    public BaseMapper<User> getMapper() {
        return userMapper;
    }

    @Override
    // value: key名称的前缀
    // key: key名称的后缀(单引号引起)
    // user::list
    @Cacheable(value = "user", key = "'list'") // 先去缓存中查询，如果没有就调用方法查询，把返回值放到缓存
    public List<User> getList() {
        System.out.println("UserServiceImpl.getList");
        return userMapper.selectList(null);
    }

    @Override
    @Cacheable(value = "user", key = "'id_'+#id")
    public User selectById(Integer id) {
        return super.selectById(id);
    }

    @Override
    @CacheEvict(value = "user", key = "'list'")
    public int deleteById(Integer id) {
        return super.deleteById(id);
    }

    @Override
    public int insert(User user) {
        return super.insert(user);
    }

    @Override
    @Caching(evict = {
        @CacheEvict(value = "user", key = "'list'"),
        @CacheEvict(value = "user", key = "'id_'+#user.id")
    })
    public int update(User user) {
        return super.update(user);
    }

    @CachePut(value = "user", key = "'id_'+#result.id") // 把方法的返回值添加到注解中
    @CacheEvict(value = "user", key = "'list'")
    @Override
    public User addUser(User user) {
        return userMapper.addUser(user);
    }

}

springboot篇】二十一. 基于springboot电商项目 七 Redis做为缓存服务的使用

springboot项目

中国加油，武汉加油！

篇幅较长，配合目录观看

案例准备

1. 项目准备

1.1 shop-temp新建springboot-redis-user（module-maven）

1.2 导相关依赖

1.3 编写User

1.4 编写Mapper接口

1.5 编写Service及其impl

1.6 编写Controller

1.7 编写程序入口

1.8 编写yml

1.9 编写页面

1.10 启动程序入口

2. Redis做为缓存服务的使用

2.1 配置yml

2.2 Impl重写getList

2.3 改进

2.4 注解改进

2.4.1 导入相关依赖

2.4.2 修改程序入口

2.4.3 配置yml

2.4.4 Impl

springboot篇】二十一. 基于springboot电商项目七 Redis做为缓存服务的使用