SpringBoot整合redis缓存(一)

2019-09-20

准备工作

1.Linux系统

2.安装redis(也可以安装docker,然后再docker中装redis,本文章就直接用Linux安装redis做演示)

  redis下载地址:http://download.redis.io/releases/redis-4.0.14.tar.gz

修改redis,开启远程访问

找到redis中的redis.conf文件并编辑(在安装路径中找到)

vim ./redis.conf

1、找到bind 127.0.0.1并注释掉

  默认127.0.0.1只能本地访问,注释掉即可ip访问

2、修改 protected-mode 属性值为no

  注释掉并把保护模式禁用以后可以IP访问

3、修改daemonize属性将no 改为yes

  将daemonize设置为yes即启动后台运行

4、开放6379端口

/sbin/iptables -I INPUT -p tcp --dport 6379 -j ACCEPT

  默认不对外开放6379

5、启动redis

redis-server /myconf/redis.conf

  redis-server默认在/usr/local/bin路径下,redis.conf在redis的安装路径下

6、测试连接

redis-cli -h 192.168.126.129 -p 6379

  redis-cli -h redis服务器IP -p 6379 -a 密码(没有设置redis密码不要写空,否则报错)

 Java代码编写

 目录结构

项目源码结构

一个user表

 

 

 代码

pom.xml文件(可以根据自己的需要来添加或修改)

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- mybatis 与 spring boot 2.x的整合包 -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>

        <!--mysql JDBC驱动 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.39</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-redis</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-cache</artifactId>
        </dependency>
    </dependencies>

 下面是springboot的配置文件application.yml,配置redis(里面都有注释解释)

server:
  port: 8081

#数据库连接
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/mytest_springboot_cache?useUnicode=true
    driver-class-name: com.mysql.jdbc.Driver
    username: root
    password: lzh

  ## Redis 配置
  redis:
    ## Redis数据库索引(默认为0)
    database: 0
    ## Redis服务器地址
    host: 192.168.126.129
    ## Redis服务器连接端口
    port: 6379
    ## Redis服务器连接密码(默认为空)
    password:
    jedis:
      pool:
        ## 连接池最大连接数(使用负值表示没有限制)
        #spring.redis.pool.max-active=8
        max-active: 8
        ## 连接池最大阻塞等待时间(使用负值表示没有限制)
        #spring.redis.pool.max-wait=-1
        max-wait: -1
        ## 连接池中的最大空闲连接
        #spring.redis.pool.max-idle=8
        max-idle: 8
        ## 连接池中的最小空闲连接
        #spring.redis.pool.min-idle=0
        min-idle: 0
    ## 连接超时时间(毫秒)
    timeout: 1200

  #将themilef的默认缓存禁用,热加载生效
  thymeleaf:
    cache: false

  #mybatis的下划线转驼峰配置
  configuration:
    map-underscore-to-camel-case: true

    #另外一种打印语句的方式
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

#打印sql时的语句
logging:
  level:
    com:
      acong:
        dao: debug
  file: d:/logs/bsbdj.log

 接着是实体类,这个比较简单就不多说了

package com.lzh.springbootstudytest.bean;

import java.io.Serializable;

/**
 * @author lzh
 * create 2019-09-18-22:32
 */
public class User implements Serializable {

    private static final long serialVersionUID = 1L;
    private int uid;
    private String userName;
    private String passWord;
    private int salary;
    public int getUid() {
        return uid;
    }
    public void setUid(int uid) {
        this.uid = uid;
    }
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public String getPassWord() {
        return passWord;
    }
    public void setPassWord(String passWord) {
        this.passWord = passWord;
    }
    public int getSalary() {
        return salary;
    }
    public void setSalary(int salary) {
        this.salary = salary;
    }
    public User(int uid, String userName, String passWord, int salary) {
        super();
        this.uid = uid;
        this.userName = userName;
        this.passWord = passWord;
        this.salary = salary;
    }
    public User() {
        super();
    }
} 

  这是controller类,用于暴露接口访问

package com.lzh.springbootstudytest.controller;

import com.lzh.springbootstudytest.bean.User;
import com.lzh.springbootstudytest.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @author lzh
 * create 2019-09-18-22:36
 */
@RestController
public class TestController {

    @Autowired
    private UserService userService;

    @RequestMapping("/queryAll")
    public List<User> queryAll(){
        List<User> lists = userService.queryAll();
        return lists;
    }

    @RequestMapping("/findUserById")
    public Map<String, Object> findUserById(@RequestParam int id){
        User user = userService.findUserById(id);
        Map<String, Object> result = new HashMap<>();
        result.put("uid", user.getUid());
        result.put("uname", user.getUserName());
        result.put("pass", user.getPassWord());
        result.put("salary", user.getSalary());
        return result;
    }

    @RequestMapping("/updateUser")
    public String updateUser(){
        User user = new User();
        user.setUid(1);
        user.setUserName("cat");
        user.setPassWord("miaomiao");
        user.setSalary(4000);

        int result = userService.updateUser(user);

        if(result != 0){
            return "update user success";
        }

        return "fail";
    }

    @RequestMapping("/deleteUserById")
    public String deleteUserById(@RequestParam int id){
        int result = userService.deleteUserById(id);
        if(result != 0){
            return "delete success";
        }
        return "delete fail";
    }
}

 接着是Mapper持久层Dao,这里主要用注解写比较方便,也可以使用mybatis的xml配置文件写sql语句

package com.lzh.springbootstudytest.mapper;

import com.lzh.springbootstudytest.bean.User;
import org.apache.ibatis.annotations.*;

import java.util.List;

/**
 * @author lzh
 * create 2019-09-18-22:32
 */
@Mapper
public interface UserDao {

    @Select("select * from user")
    List<User> queryAll();

    @Select("select * from user where uid = #{id}")
    User findUserById(int id);

    @Update("UPDATE USER SET username = CASE WHEN (#{userName} != NULL) AND (#{userName} != '') THEN #{userName},PASSWORD = CASE WHEN (#{passWord} != NULL) AND (#{passWord} != '') THEN #{passWord},salary = CASE WHEN (#{salary} != 0) THEN #{salary} WHERE uid = #{uid}")
    int updateUser(@Param("user") User user);

    @Delete("delete from user where uid = #{id}")
    int deleteUserById(int id);

}

 service层,这里主要是使用redis模板来写

package com.lzh.springbootstudytest.service;

import com.lzh.springbootstudytest.bean.User;
import com.lzh.springbootstudytest.mapper.UserDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.stereotype.Service;

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

/**
 * @author lzh
 * create 2019-09-18-22:33
 */
@Service
public class UserService {

    @Autowired
    private UserDao userDao;

    @Autowired
    private RedisTemplate redisTemplate;

    public List<User> queryAll() {
        return userDao.queryAll();
    }

    /**
     * 获取用户策略:先从缓存中获取用户,没有则取数据表中 数据,再将数据写入缓存
     */
    public User findUserById(int id) {
        String key = "user_" + id;

        ValueOperations<String, User> operations = redisTemplate.opsForValue();

        //判断redis中是否有键为key的缓存
        boolean hasKey = redisTemplate.hasKey(key);

        if (hasKey) {
            User user = operations.get(key);
            System.out.println("从缓存中获得数据:"+user.getUserName());
            System.out.println("------------------------------------");
            return user;
        } else {
            User user = userDao.findUserById(id);
            System.out.println("查询数据库获得数据:"+user.getUserName());
            System.out.println("------------------------------------");

            // 写入缓存
            operations.set(key, user, 5, TimeUnit.HOURS);
            return user;
        }
    }

    /**
     * 更新用户策略:先更新数据表,成功之后,删除原来的缓存,再更新缓存
     */
    public int updateUser(User user) {
        ValueOperations<String, User> operations = redisTemplate.opsForValue();
        int result = userDao.updateUser(user);
        if (result != 0) {
            String key = "user_" + user.getUid();
            boolean haskey = redisTemplate.hasKey(key);
            if (haskey) {
                redisTemplate.delete(key);
                System.out.println("删除缓存中的key-----------> " + key);
            }
            // 再将更新后的数据加入缓存
            User userNew = userDao.findUserById(user.getUid());
            if (userNew != null) {
                operations.set(key, userNew, 3, TimeUnit.HOURS);
            }
        }
        return result;
    }

    /**
     * 删除用户策略:删除数据表中数据,然后删除缓存
     */
    public int deleteUserById(int id) {
        int result = userDao.deleteUserById(id);
        String key = "user_" + id;
        if (result != 0) {
            boolean hasKey = redisTemplate.hasKey(key);
            if (hasKey) {
                redisTemplate.delete(key);
                System.out.println("删除了缓存中的key:" + key);
            }
        }
        return result;
    }

} 

  

  这里主要是使用RedisTemplate来对远程redis操作,每次访问controller暴露的接口,首先判断redis缓存中是否存在该数据,若不存在就从数据库中读取数据,然后保存到redis缓存中,当下次访问的时候,就直接从缓存中取出来。这样就不用每次都执行sql语句,能够提高访问速度。 但是在保存数据到缓存中,通过设置键和值和超时删除,注意设置超时删除缓存时间不要太长,否则会给服务器带来压力。

执行spring boot的启动类,访问http://localhost:8081/findUserById?id=1

再次访问http://localhost:8081/findUserById?id=1就是从缓存中获取保存的数据