乐观意味着不对无可奈何的事情怨天尤人。怨天尤人是那些失去自我信赖的人的接口——雷音
首先引入redis、json依赖
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-json</artifactId> </dependency>
然后进行配置
package com.ruben.simplecache; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cache.CacheManager; import org.springframework.cache.annotation.EnableCaching; import org.springframework.context.annotation.Bean; 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.serializer.GenericJackson2JsonRedisSerializer; import org.springframework.data.redis.serializer.RedisSerializationContext; import org.springframework.data.redis.serializer.StringRedisSerializer; @EnableCaching @SpringBootApplication public class SimpleCacheApplication { @Bean public CacheManager cacheManager(RedisConnectionFactory connectionFactory) { final RedisCacheWriter redisCacheWriter = RedisCacheWriter.lockingRedisCacheWriter(connectionFactory); final RedisCacheConfiguration cacheConfig = RedisCacheConfiguration.defaultCacheConfig() .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(new StringRedisSerializer())) .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(new GenericJackson2JsonRedisSerializer())); return new RedisCacheManager(redisCacheWriter, cacheConfig); } public static void main(String[] args) { SpringApplication.run(SimpleCacheApplication.class, args); } }
别忘了给我们的实体类无参构造器
package com.ruben.simplecache; public class Book { private String isbn; private String title; public Book() { } public Book(String isbn, String title) { this.isbn = isbn; this.title = title; } public String getIsbn() { return isbn; } public void setIsbn(String isbn) { this.isbn = isbn; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } @Override public String toString() { return "Book{" + "isbn='" + isbn + '\'' + ", title='" + title + '\'' + '}'; } }
运行AppRunner
package com.ruben.simplecache; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.boot.CommandLineRunner; import org.springframework.stereotype.Component; @Component public class AppRunner implements CommandLineRunner { private static final Logger logger = LoggerFactory.getLogger(AppRunner.class); private final BookRepository bookRepository; public AppRunner(BookRepository bookRepository) { this.bookRepository = bookRepository; } @Override public void run(String... args) throws Exception { logger.info(".... Fetching books"); logger.info("isbn-1234 -->" + bookRepository.getByIsbn("isbn-1234")); logger.info("isbn-4567 -->" + bookRepository.getByIsbn("isbn-4567")); logger.info("isbn-1234 -->" + bookRepository.getByIsbn("isbn-1234")); logger.info("isbn-4567 -->" + bookRepository.getByIsbn("isbn-4567")); logger.info("isbn-1234 -->" + bookRepository.getByIsbn("isbn-1234")); logger.info("isbn-1234 -->" + bookRepository.getByIsbn("isbn-1234")); logger.info(".... Updating books"); logger.info("isbn-1234 -->" + bookRepository.updateByIsbn(new Book("isbn-1234", "Some book"))); logger.info("isbn-4567 -->" + bookRepository.updateByIsbn(new Book("isbn-4567", "Some book"))); logger.info(".... Fetching books"); logger.info("isbn-1234 -->" + bookRepository.getByIsbn("isbn-1234")); logger.info("isbn-4567 -->" + bookRepository.getByIsbn("isbn-4567")); logger.info("... Removing Books"); logger.info("isbn-1234 -->" + bookRepository.removeByIsbn("isbn-1234")); logger.info("isbn-4567 -->" + bookRepository.removeByIsbn("isbn-4567")); logger.info(".... Fetching books"); logger.info("isbn-1234 -->" + bookRepository.getByIsbn("isbn-1234")); logger.info("isbn-4567 -->" + bookRepository.getByIsbn("isbn-4567")); } }
我们的持久层SimpleBookRepository代码和AppRunner一样，都不需要变动
package com.ruben.simplecache; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.cache.annotation.CacheEvict; import org.springframework.cache.annotation.CachePut; import org.springframework.cache.annotation.Cacheable; import org.springframework.stereotype.Component; @Component public class SimpleBookRepository implements BookRepository { private static final Logger log = LoggerFactory.getLogger(SimpleBookRepository.class); @Override @Cacheable("books") public Book getByIsbn(String isbn) { simulateSlowService(); log.warn("getByIsbn called {}", isbn); return new Book(isbn, "Some book"); } @Override @CacheEvict("books") public Book removeByIsbn(String isbn) { log.warn("removeByIsbn called {}", isbn); simulateSlowService(); return new Book(isbn, "Some book"); } @Override @CachePut("books") public Book updateByIsbn(Book book) { log.warn("updateByIsbn called {}", book); simulateSlowService(); return book; } // Don't do this at home private void simulateSlowService() { try { long time = 3000L; Thread.sleep(time); } catch (InterruptedException e) { throw new IllegalStateException(e); } } }
运行结果：
可以看到其是使用注解上的value以及参数作为缓存的key，所以我们updateByIsBn需要改为用String isbn作为参数
该方法将由原本的根据IsBn更新，改为从数据库中查询数据，同步到缓存
@Override @CachePut("books") public Book updateByIsbn(String isbn) { final Book book = new Book(isbn, "Some book"); log.warn("updateByIsbn called {}", book); simulateSlowService(); return book; }
修改AppRunner后再次运行
package com.ruben.simplecache; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.boot.CommandLineRunner; import org.springframework.stereotype.Component; @Component public class AppRunner implements CommandLineRunner { private static final Logger logger = LoggerFactory.getLogger(AppRunner.class); private final BookRepository bookRepository; public AppRunner(BookRepository bookRepository) { this.bookRepository = bookRepository; } @Override public void run(String... args) throws Exception { logger.info(".... Fetching books"); logger.info("isbn-1234 -->" + bookRepository.getByIsbn("isbn-1234")); logger.info("isbn-4567 -->" + bookRepository.getByIsbn("isbn-4567")); logger.info("isbn-1234 -->" + bookRepository.getByIsbn("isbn-1234")); logger.info("isbn-4567 -->" + bookRepository.getByIsbn("isbn-4567")); logger.info("isbn-1234 -->" + bookRepository.getByIsbn("isbn-1234")); logger.info("isbn-1234 -->" + bookRepository.getByIsbn("isbn-1234")); logger.info(".... Updating books"); logger.info("isbn-1234 -->" + bookRepository.updateByIsbn("isbn-1234")); logger.info("isbn-4567 -->" + bookRepository.updateByIsbn("isbn-4567")); logger.info(".... Fetching books"); logger.info("isbn-1234 -->" + bookRepository.getByIsbn("isbn-1234")); logger.info("isbn-4567 -->" + bookRepository.getByIsbn("isbn-4567")); logger.info("... Removing Books"); logger.info("isbn-1234 -->" + bookRepository.removeByIsbn("isbn-1234")); logger.info("isbn-4567 -->" + bookRepository.removeByIsbn("isbn-4567")); logger.info(".... Fetching books"); logger.info("isbn-1234 -->" + bookRepository.getByIsbn("isbn-1234")); logger.info("isbn-4567 -->" + bookRepository.getByIsbn("isbn-4567")); } }
