【译】Spring的@EnableCaching注解
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Spring的@EnableCaching注解
@EnableCaching注解是spring framework中的注解驱动的缓存管理功能。自spring版本3.1起加入了该注解。如果你使用了这个注解，那么你就不需要在XML文件中配置cache manager了。
当你在配置类(@Configuration)上使用@EnableCaching注解时，会触发一个post processor，这会扫描每一个spring bean，查看是否已经存在注解对应的缓存。如果找到了，就会自动创建一个代理拦截方法调用，使用缓存的bean执行处理。
如果你对缓存感兴趣并想了解更多，请阅读spring caching. 本文会帮助你了解如何使用@EnableCaching注解。
接下来的例子演示了@EnableCaching的用法。在代码中，我缓存了Book类找那个的方法。
代码
//Book.java
import org.springframework.cache.annotation.Cacheable;
public class Book {
@Cacheable(value = { "sampleCache" })
public String getBook(int id) {
System.out.println("Method executed..");
if (id == 1) {
return "Book 1";
} else {
return "Book 2";
}
}
}
//CachingConfig.java
import java.util.Arrays;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.concurrent.ConcurrentMapCache;
import org.springframework.cache.support.SimpleCacheManager;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
@EnableCaching
public class CachingConfig {
@Bean
public Book book() {
return new Book();
}
@Bean
public CacheManager cacheManager() {
SimpleCacheManager cacheManager = new SimpleCacheManager();
cacheManager.setCaches(Arrays.asList(new ConcurrentMapCache("sampleCache")));
return cacheManager;
}
}
上面的java config和下面的xml配置文件是等效的：
<beans>
<cache:annotation-driven/>
<bean id="book" class="Book"/>
<bean id="cacheManager" class="org.springframework.cache.support.SimpleCacheManager">
<property name="caches">
<set>
<bean class="org.springframework.cache.concurrent.ConcurrentMapCacheFactoryBean">
<property name="name" value="sampleCache"/>
</bean>
</set>
</property>
</bean>
</beans>
//EnableCachingAnnotationExample.java
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
public class EnableCachingAnnotationExample {
public static void main(String[] args) {
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
ctx.register(CachingConfig.class);
ctx.refresh();
Book book = ctx.getBean(Book.class);
// calling getBook method first time.
System.out.println(book.getBook(1));
// calling getBook method second time. This time, method will not
// execute.
System.out.println(book.getBook(1));
// calling getBook method third time with different value.
System.out.println(book.getBook(2));
ctx.close();
}
}
会得到如下的输出
Method executed..
Book 1
Book 1
Method executed..
Book 2
