标签：spring pack pac package 方法 factor 注解 测试 magic
@Conditional
根据某个条件来决定是否创建Bean实例
代码下载地址：http://download.csdn.net/download/poiuy1991719/9965794
创建一个Bean类：
package com.bean.conditional; import org.springframework.context.annotation.Conditional; import org.springframework.stereotype.Component; @Component("magicBeanName")//重命名：配置类里面的方法与之对应 @Conditional(MagicCheck.class)//决定是否创建Bean的条件类 public class MagicBean { private String name="MagicBean"; public MagicBean() { System.out.println("MagicBean:实例化"); } public void showName(){ System.out.println("Show Name is:"+name); } }
创建一个Config配置类：配置类指定了一个Check类：
package com.bean.conditional; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.ComponentScan; import org.springframework.context.annotation.Conditional; import org.springframework.context.annotation.Configuration; @Configuration @ComponentScan(basePackages={"com.bean"}) public class BeanConfigs { @Bean @Conditional(MagicCheck.class)//决定是否创建Bean对象 public MagicBean magicBeanName(){//方法名来源，Bean类的注解：@Component("magicBeanName") return new MagicBean(); } }
Check类决定是否创建Bean的实例：Check类需是Condition类的一个实现：
package com.bean.conditional; import org.springframework.context.annotation.Condition; import org.springframework.context.annotation.ConditionContext; import org.springframework.core.type.AnnotatedTypeMetadata; //决定Bean的创建，需是Condition的一个接口 public class MagicCheck implements Condition { public boolean matches(ConditionContext arg0, AnnotatedTypeMetadata arg1) { return true;//创建Bean实例 // return false;//不创建Bean实例 } }
测试类：
package test;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import com.bean.conditional.BeanConfigs;
import com.bean.conditional.MagicBean;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(classes={BeanConfigs.class})
public class test {
@Autowired
MagicBean mb;
@Test
public void selfTest(){
if(mb==null){
System.out.println("MagicCheck类决定了Bean的创建，MagicCheck类方法返回：false");
}else{
System.out.println("MagicCheck类决定了Bean的创建，MagicCheck类方法返回：true");
mb.showName();
}
}
}
Spring In Action-3.2@Conditional条件化Bean
标签：spring pack pac package 方法 factor 注解 测试 magic
原文地址：http://www.cnblogs.com/zjsy/p/7482361.html
