SpringBoot使用缓存及整合Redis

时间：2020-04-14 17:40:36 阅读：52 评论：0 收藏：0 [点我收藏+]

1.环境准备

创建springboot项目

引入依赖如下

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-cache</artifactId>
        </dependency>
        <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>2.1.2</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>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
</dependencies>

配置application.properties

spring.datasource.url=jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8&useSSL=false
spring.datasource.username=root
spring.datasource.password=991105
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

#mybatis开启驼峰命名法
mybatis.configuration.map-underscore-to-camel-case=true

创建实体类Employee和Department

package com.chenpeng.springcache.bean;

import java.io.Serializable;

public class Employee implements Serializable {
    private Integer id;
    private String lastName;
    private String email;
    private Integer gender; //性别 1男  0女
    private Integer dId;


    public Employee() {
        super();
    }


    public Employee(Integer id, String lastName, String email, Integer gender, Integer dId) {
        super();
        this.id = id;
        this.lastName = lastName;
        this.email = email;
        this.gender = gender;
        this.dId = dId;
    }

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public Integer getGender() {
        return gender;
    }

    public void setGender(Integer gender) {
        this.gender = gender;
    }

    public Integer getdId() {
        return dId;
    }

    public void setdId(Integer dId) {
        this.dId = dId;
    }

    @Override
    public String toString() {
        return "Employee [id=" + id + ", lastName=" + lastName + ", email=" + email + ", gender=" + gender + ", dId="
                + dId + "]";
    }
}


package com.chenpeng.springcache.bean;

public class Department {
    private Integer id;
    private String departmentName;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getDepartmentName() {
        return departmentName;
    }

    public void setDepartmentName(String departmentName) {
        this.departmentName = departmentName;
    }

    @Override
    public String toString() {
        return "Department{" +
                "id=" + id +
                ", departmentName=‘" + departmentName + ‘\‘‘ +
                ‘}‘;
    }
}

创建mapper层接口

package com.chenpeng.springcache.mapper;

import com.chenpeng.springcache.bean.Employee;
import org.apache.ibatis.annotations.*;

@Mapper
public interface EmployeeMapper {
    @Select("select * from employee where id = #{id}")
    Employee getEmpById(Integer id);

    @Insert("insert into employee(lastName,email,gender,d_id) values(#{lastName},#{email},#{gender},#{dId})")
    void insertEmp(Employee employee);

    @Update("update employee set lastName = #{lastName},email = #{email},gender = #{gender},d_id = #{dId} where id = #{id}")
    void updateEmp(Employee employee);

    @Delete("delete from employee where id = #{id}")
    void deleteEmp(Integer id);

    @Select("select * from employee where lastName = #{lastName}")
    Employee getEmpByLastName(String lastName);
}


package com.chenpeng.springcache.mapper;

import com.chenpeng.springcache.bean.Department;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;

@Mapper
public interface DepartmentMapper {

    @Select("select * from department where id = #{id}")
    public Department getDeptById(Integer id);

}

创建service层类

package com.chenpeng.springcache.service;

import com.chenpeng.springcache.bean.Employee;
import com.chenpeng.springcache.mapper.EmployeeMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class EmployeeService {

    @Autowired
    EmployeeMapper employeeMapper;

    public Employee getEmp(Integer id){
        System.out.println("查找"+id+"号员工");
        Employee emp = employeeMapper.getEmpById(id);
        return emp;
    }
}


package com.chenpeng.springcache.service;

import com.chenpeng.springcache.bean.Department;
import com.chenpeng.springcache.mapper.DepartmentMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class DepartmentService {

    @Autowired
    DepartmentMapper departmentMapper;

    public Department getDept(Integer id){
        System.out.println("查找"+id+"号部门");
        Department dept = departmentMapper.getDeptById(id);
        return dept;
    }
}

创建controller层类

package com.chenpeng.springcache.controller;

import com.chenpeng.springcache.bean.Employee;
import com.chenpeng.springcache.service.EmployeeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class EmployeeController {

    @Autowired
    EmployeeService employeeService;

    @GetMapping("/emp/{id}")
    public Employee getEmployee(@PathVariable("id") Integer id){
        Employee employee = employeeService.getEmp(id);
        return employee;
    }
}


package com.chenpeng.springcache.controller;

import com.chenpeng.springcache.bean.Department;
import com.chenpeng.springcache.service.DepartmentService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class DepartmentController {

    @Autowired
    DepartmentService departmentService;

    @GetMapping("/dept/{id}")
    public Department getDept(@PathVariable("id") Integer id){
        Department dept = departmentService.getDept(id);
        return dept;
    }
}

2.使用缓存

@Cacheable

作用在方法上，将方法的运行结构进行缓存，以后再要相同的数据，直接从缓存中获取，不用再调用方法

属性：

cacheNames/value：指定缓存组件的名字
key：缓存数据使用的key，可以用它来指定，默认是使用方法参数的值，例如：1-方法的返回值，可以使用#SpEl，如#id指参数id的值（@Cacheable不能使用#result）
keyGenerator：key的生成器，可以自己指定key的生成器的组件id，key/keyGenerator：二选一使用
cacheManager：指定缓存的管理器，（CacheManager管理多个Cache组件，对缓存的真正CRUD操作在Cache数组中，每一个缓存组件有自己唯一一个名字）
cacheResolver：指定缓存的解析器
condition：指定符合条件的情况下才缓存，如：condition = "#a0>1"：第一个参数的值大于1时才进行缓存
unless：否定缓存，当unless指定的条件为true，方法的返回值就不会被缓存，可以获取到结果进行判断，如unless = "#result == null"：结果为空时不缓存
sync：是否使用异步模式

运行时机：

先进行缓存，再调用方法

@Cacheable(cacheNames = "emp")
    public Employee getEmp(Integer id){
        System.out.println("查找"+id+"号员工");
        Employee emp = employeeMapper.getEmpById(id);
        return emp;
    }

自定义keyGenerator：

package com.chenpeng.springcache.config;

import org.springframework.cache.interceptor.KeyGenerator;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.lang.reflect.Method;
import java.util.Arrays;

/*
自定义key的生成策略
 */
@Configuration
public class MyCacheConfig {

    @Bean("myKeyGenerator")
    public KeyGenerator keyGenerator(){
        return new KeyGenerator(){
            @Override
            public Object generate(Object o, Method method, Object... objects) {
                return method.getName()+Arrays.asList(objects).toString();
            }
        };
    }
}

@CachePut

即调用方法，又更新缓存数据，修改了数据库的某个数据，同时更新缓存

注意需要指定@CachePut的key，使@CachePut的key与@Cacheable的key一样

运行时机：

先调用方法，再将方法的结果缓存起来

@CachePut(value = "emp", key = "#result.id")
    public Employee updateEmp(Employee employee){
        System.out.println("更新"+employee);
        employeeMapper.updateEmp(employee);
        return employee;
    }

@CacheEvict

清除缓存

属性：

key：指定要清除的数据
allEntries = true：指定清除这个缓存中所有的数据
beforeInvocation = false：缓存的清除是否在方法之前执行，默认代表缓存清除操作是在方法执行之后执行，如果出现异常缓存就不会清除
beforeInvocation = true：代表清除缓存操作是在方法执行之前执行，无论方法是否出现异常，缓存都清除

@CacheEvict(value = "emp",beforeInvocation = true)
    public void deleteEmp(Integer id){
        System.out.println("删除"+id+"号员工");
        employeeMapper.deleteEmp(id);
    }

@Caching

定义复杂的缓存规则

@Caching(
            cacheable = {
                    @Cacheable(value = "emp",key="#lastName")
            },
            put = {
                    @CachePut(value="emp",key="#result.id"),
                    @CachePut(value="emp",key="#result.email")
            }
    )
    public Employee getEmpByLastName(String lastName){
        return employeeMapper.getEmpByLastName(lastName);
    }

缓存原理和运行流程

原理

自动配置类：CacheAutoConfiguration
缓存的配置类：

org.springframework.boot.autoconfigure.cache.GenericCacheConfiguration

org.springframework.boot.autoconfigure.cache.JCacheCacheConfiguration

org.springframework.boot.autoconfigure.cache.EhCacheCacheConfiguration

org.springframework.boot.autoconfigure.cache.HazelcastCacheConfiguration

org.springframework.boot.autoconfigure.cache.InfinispanCacheConfiguration

org.springframework.boot.autoconfigure.cache.CouchbaseCacheConfiguration

org.springframework.boot.autoconfigure.cache.RedisCacheConfiguration

org.springframework.boot.autoconfigure.cache.CaffeineCacheConfiguration

org.springframework.boot.autoconfigure.cache.GuavaCacheConfiguration

org.springframework.boot.autoconfigure.cache.SimpleCacheConfiguration

org.springframework.boot.autoconfigure.cache.NoOpCacheConfiguration
SimpleCacheConfiguration默认生效
给容器中注册了一个CacheManager：ConcurrentMapCacheManager
可以获取和创建ConcurrentMapCache类型的缓存组件，将数据保存在ConcurrentMap中

运行流程

@Cacheable：

方法运行之前，先去查询Cache缓存组件，按照cacheNames指定的名字获取，CacheManager先获取相应的缓存，第一次获取缓存如果没有Cache组件会自动创建
按照key去Cache中查找缓存的数据，默认是方法的参数
- key是按照某种策略生成的，默认使用SimpleKeyGenerator生成key
  - SimpleKeyGenerator生成key的策略
    - 如果没有参数：key = newSimpleKey()
    - 如果有一个参数：key = 参数的值
    - 如果有多个参数：key = new SimpleKey(params)
没有查到缓存就调用目标方法
将目标方法返回的结果放进缓存中

整合Redis管理缓存

1.环境准备

利用Docker安装Redis镜像运行Redis容器

docker pull redis
docker run -d -p 8089:6379 redis

下载安装RedisDeskTopManager并连接运行的redis容器

pom文件中引入redis的依赖

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

application.properties中添加redis的配置

#指定IP地址
spring.redis.host=xxx
#指定端口号
spring.redis.port=8089

2.测试缓存

实体类需要实现序列化接口

RedisCacheManager默认使用jdk的序列化器

3.自定义CacheManager

创建MyRedisConfig类，把默认的jdk序列化器改为json的序列化器

package com.chenpeng.springcache.config;

import com.chenpeng.springcache.bean.Employee;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.cache.RedisCacheWriter;
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.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext;
import org.springframework.data.redis.serializer.RedisSerializer;

import java.net.UnknownHostException;
import java.time.Duration;

@Configuration
public class MyRedisConfig {

    /**
     * 测试时使用
     * @param redisConnectionFactory
     * @return
     * @throws UnknownHostException
     */
    @Bean
    public RedisTemplate<Object, Employee> empRedisTemplate(RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {
        RedisTemplate<Object, Employee> template = new RedisTemplate<Object, Employee>();
        template.setConnectionFactory(redisConnectionFactory);
        Jackson2JsonRedisSerializer<Employee> ser = new Jackson2JsonRedisSerializer<Employee>(Employee.class);
        template.setDefaultSerializer(ser);
        return template;
    }

    /**
     * springboot2.x版本RedisCacheManager自定义配置
     * @param redisConnectionFactory
     * @return
     */
    @Bean
    public RedisCacheManager employeeCacheManager(RedisConnectionFactory redisConnectionFactory){
        //初始化一个RedisCacheWriter
        RedisCacheWriter redisCacheWriter = RedisCacheWriter.nonLockingRedisCacheWriter(redisConnectionFactory);
        //设置CacheManager的值序列化方式为json序列化
        RedisSerializer<Object> jsonSerializer = new GenericJackson2JsonRedisSerializer();
        RedisSerializationContext.SerializationPair<Object> pair = RedisSerializationContext.SerializationPair.fromSerializer(jsonSerializer);
        RedisCacheConfiguration defaultCacheConfig = RedisCacheConfiguration.defaultCacheConfig().serializeValuesWith(pair);
        //设置默认过期时间1天
        defaultCacheConfig.entryTtl(Duration.ofDays(1));
        //初始化RedisCacheManager
        RedisCacheManager cacheManager = new RedisCacheManager(redisCacheWriter, defaultCacheConfig);
        return cacheManager;
    }
}

SpringBoot使用缓存及整合Redis

原文：https://www.cnblogs.com/codeDD/p/12699272.html

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