分布式数据存储 之 Redis(二) —— spring中的缓存抽象
一、spring boot 中的 StringRedisTemplate
1.StringRedisTemplate Demo
第一步：引入redis依赖
最重要的依赖
compile('org.springframework.boot:spring-boot-starter-data-redis')
此依赖为springCloud 父项目 依赖（但已添加 redis 依赖）
buildscript {
ext {
springBootVersion = '2.1.2.RELEASE'
}
repositories {
mavenLocal() //maven本地仓库
maven {
url = "http://maven.aliyun.com/nexus/content/groups/public"
}
mavenCentral()//maven中心仓库
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
}
}
subprojects {
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
group = 'com.lichuang.kukri'
version = '1.0.0'
sourceCompatibility = 1.8
repositories {
mavenLocal() //maven本地仓库
maven {
url = "http://maven.aliyun.com/nexus/content/groups/public"
}
mavenCentral()//maven中心仓库
}
ext {
springCloudVersion = 'Greenwich.RELEASE'
}
dependencies {
compile('org.springframework.boot:spring-boot-starter-actuator')
compile('org.springframework.boot:spring-boot-starter-web')
compile('org.springframework.cloud:spring-cloud-starter')
testCompile('org.springframework.boot:spring-boot-starter-test')
//redis 依赖
compile('org.springframework.boot:spring-boot-starter-data-redis')
}
dependencyManagement {
imports {
mavenBom "org.springframework.cloud:spring-cloud-dependencies:${springCloudVersion}"
}
}
}
第二步：创建 StringRedisTemplate 的 Bean
由 StringRedisTemplate 的构造函数可知需要 RedisConnectionFactory 的 Bean，又由 RedisConnectionFactory 可知需要 RedisStandaloneConfiguration 的 Bean， RedisStandaloneConfiguration 的构造函数中需要有 hostname 以及 port
@Configuration
@ComponentScan
public class AppConfig {
//xxxTemplate -> 设计模式之一 模板方法设计模式
@Bean
public RedisStandaloneConfiguration redisStandaloneConfiguration(){
RedisStandaloneConfiguration redisStandaloneConfiguration = new RedisStandaloneConfiguration("hostname",6379);
return redisStandaloneConfiguration;
}
@Bean
public RedisConnectionFactory redisConnectionFactory(){
LettuceConnectionFactory connectionFactory = new LettuceConnectionFactory(redisStandaloneConfiguration());
return connectionFactory;
}
@Bean
public StringRedisTemplate stringRedisTemplate(){
StringRedisTemplate redisTemplate = new StringRedisTemplate(redisConnectionFactory());
return redisTemplate;
}
}
第三步：获取 StringRedisTemplate 进行运用
- 添加数据至Redis：
redisTemplate.opsForValue().set("name","test"); - 从Redis 获取数据：
redisTemplate.opsForValue().get("name")
public class RedisServer {
public static void main(String[] args) {
AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(AppConfig.class);
StringRedisTemplate redisTemplate = applicationContext.getBean(StringRedisTemplate.class);
redisTemplate.opsForValue().set("name","test");
//System.out.println(redisTemplate.opsForValue().get("name"));
/* redisTemplate.watch("name");
redisTemplate.multi();
redisTemplate.exec();*/
}
}
二、 Cache Abstraction
1.核心接口
CachManager
Spring's central cache manager SPI.
方法
Cache getCache(String name);
Collection getCacheNames();
Cache
Interface that defines common cache operations
常见实现类
- ConcurrentMapCache
- RedisCache
- EhCacheCache
KeyGenerator
SimpleKeyGenerator(默认实现类)
2. 常见注解
@Cacheable
如果缓存中有值，则使用缓存中的值；如果没有则执行业务方法并存入缓存中
属性
-
condition
判断
-
unless
非
@CachePut
每次都会执行业务方法，并设置缓存
@CacheEvict
每次都会执行业务方法，并删除缓存
3. Cache Abstraction Demo
第一步：引入依赖
dependencies {
compile('org.springframework.boot:spring-boot-starter-data-redis')
compile group: 'org.projectlombok', name: 'lombok', version: '1.18.6'
compile group: 'com.alibaba', name: 'fastjson', version: '1.2.56'
}
第二步：创建 CacheManager 的 Bean
注：
1. GenericFastJsonRedisSerializer 类 使 Value 的 储存方式 为 Josn
@Configuration
@ComponentScan
@MapperScan("com.lichuang.kukri.springcloudproject.config.dao")
@EnableCaching
public class AppConfig {
//xxxTemplate -> 设计模式之一 模板方法设计模式
@Bean
public RedisStandaloneConfiguration redisStandaloneConfiguration(){
RedisStandaloneConfiguration redisStandaloneConfiguration = new RedisStandaloneConfiguration("hostname",6379);
return redisStandaloneConfiguration;
}
@Bean
public CacheManager cacheManager(){
RedisCacheWriter redisCacheWriter = RedisCacheWriter.nonLockingRedisCacheWriter(redisConnectionFactory());
RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig()
.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(new GenericFastJsonRedisSerializer()));
RedisCacheManager redisCacheManager = new RedisCacheManager(redisCacheWriter,redisCacheConfiguration);
return redisCacheManager;
}
}
第三步：创建 Service
@Service
public class CacheService {
@CachePut(cacheNames = "person")
public Person update(int age){
Person person = new Person();
person.setPersonName("admin");
person.setAge(age);
return person;
}
@Cacheable(cacheNames = "person")
public Person selectP(int age){
Person person = new Person();
person.setPersonName("test");
person.setAge(age);
return person;
}
@Cacheable(cacheNames = "cache")
public String selectC(int i){
System.out.println("select");
return "admin";
}
}
Person.java(实体类)
public class Person {
private String personName;
private int age;
public String getPersonName() {
return personName;
}
public void setPersonName(String personName) {
this.personName = personName;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
第四步：运行
public class RedisServer {
public static void main(String[] args) {
AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(AppConfig.class);
PersonDao personDao = applicationContext.getBean(PersonDao.class);
List<Person> people = personDao.select();
for (int i = 0; i < people.size(); i++) {
System.out.println(people.get(i).getPersonName() + "-" + people.get(i).getAge());
}
/*CacheService cacheService = applicationContext.getBean(CacheService.class);
for (int i = 0; i < 2; i++) {
//System.out.println(cacheService.selectC(i));
cacheService.update(i);
}*/
}
}
第五步：在 Redis 中获取
127.0.0.1:6379> get cache::0
"\"admin\""
127.0.0.1:6379> get person::0
"{\"@type\":\"com.bean.Person\",\"age\":1,\"name\":\"test\"}"