Spring @Configuration和FactoryBean

考虑使用FactoryBean通过Spring配置文件定义缓存： <cache:annotation-driven /><context:component-scan base-package='org.bk.samples.cachexml'></context:component-scan><bean id='cacheManager' class='org.springframework.cache.support.SimpleCacheManager'><property name='caches'><set><ref bean='defaultCache'/></set></property></bean><bean name='defaultCache' class='org.springframework.cache.concurrent.ConcurrentMapCacheFactoryBean'><property name='name' value='default'/></bean>

工厂bean ConcurrentMapCacheFactoryBean是一个依次负责创建Cache bean的bean。

我第一次尝试将此设置转换为@Configuration样式：

@Bean public SimpleCacheManager cacheManager(){SimpleCacheManager cacheManager = new SimpleCacheManager();List<Cache> caches = new ArrayList<Cache>();ConcurrentMapCacheFactoryBean cacheFactoryBean = new ConcurrentMapCacheFactoryBean();cacheFactoryBean.setName('default');caches.add(cacheFactoryBean.getObject());cacheManager.setCaches(caches );return cacheManager; }

但是，这没有用，原因是我在这里完全绕过了一些Spring bean生命周期机制。 事实证明，ConcurrentMapCacheFactoryBean还实现了InitializingBean接口，并在InitializingBean的'afterPropertiesSet'方法中对缓存进行了急切的初始化。 现在，通过直接调用factoryBean.getObject（），我完全绕过了afterPropertiesSet方法。

有两种可能的解决方案：
1.以与在XML中定义的相同方式定义FactoryBean：

@Bean public SimpleCacheManager cacheManager(){SimpleCacheManager cacheManager = new SimpleCacheManager();List<Cache> caches = new ArrayList<Cache>();caches.add(cacheBean().getObject());cacheManager.setCaches(caches );return cacheManager; }@Bean public ConcurrentMapCacheFactoryBean cacheBean(){ConcurrentMapCacheFactoryBean cacheFactoryBean = new ConcurrentMapCacheFactoryBean();cacheFactoryBean.setName('default');return cacheFactoryBean; }

在这种情况下，从@Bean方法返回一个显式的FactoryBean，Spring将负责在此bean上调用生命周期方法。

2.复制相关生命周期方法中的行为，在此特定实例中，我知道FactoryBean在afterPropertiesSet方法中实例化ConcurrentMapCache，我可以通过以下方式直接复制此行为：

@Bean public SimpleCacheManager cacheManager(){SimpleCacheManager cacheManager = new SimpleCacheManager();List<Cache> caches = new ArrayList<Cache>();caches.add(cacheBean());cacheManager.setCaches(caches );return cacheManager; }@Bean public Cache cacheBean(){Cache cache = new ConcurrentMapCache('default');return cache; }

将FactoryBean从xml转换为@Configuration时要记住的一点。

注意：
可以根据需要进行一页有效的测试：

package org.bk.samples.cache;import static org.hamcrest.MatcherAssert.assertThat;import static org.hamcrest.Matchers.equalTo;import java.util.ArrayList;import java.util.List;import java.util.Random;import org.junit.Test;import org.junit.runner.RunWith;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.cache.Cache;import org.springframework.cache.annotation.Cacheable;import org.springframework.cache.annotation.EnableCaching;import org.springframework.cache.concurrent.ConcurrentMapCacheFactoryBean;import org.springframework.cache.support.SimpleCacheManager;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.ComponentScan;import org.springframework.context.annotation.Configuration;import org.springframework.stereotype.Component;import org.springframework.test.context.ContextConfiguration;import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;@RunWith(SpringJUnit4ClassRunner.class)@ContextConfiguration(classes={TestSpringCache.TestConfiguration.class})public class TestSpringCache {@Autowired TestService testService;@Testpublic void testCache() {String response1 = testService.cachedMethod('param1', 'param2');String response2 = testService.cachedMethod('param1', 'param2');assertThat(response2, equalTo(response1));}@Configuration@EnableCaching@ComponentScan('org.bk.samples.cache')public static class TestConfiguration{@Beanpublic SimpleCacheManager cacheManager(){SimpleCacheManager cacheManager = new SimpleCacheManager();List<Cache> caches = new ArrayList<Cache>();caches.add(cacheBean().getObject());cacheManager.setCaches(caches );return cacheManager;}@Beanpublic ConcurrentMapCacheFactoryBean cacheBean(){ConcurrentMapCacheFactoryBean cacheFactoryBean = new ConcurrentMapCacheFactoryBean();cacheFactoryBean.setName('default');return cacheFactoryBean;}}}interface TestService{String cachedMethod(String param1,String param2);}@Componentclass TestServiceImpl implements TestService{@Cacheable(value='default', key='#p0.concat('-').concat(#p1)')public String cachedMethod(String param1, String param2){return 'response ' + new Random().nextInt();}}

参考： all和其他博客中来自我们JCG合作伙伴 Biju Kunjummen的Spring @Configuration和FactoryBean 。

翻译自: https://www.javacodegeeks.com/2012/08/spring-configuration-and-factorybean.html

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