SpringBoot实现懒加载@Lazy

@Lazy使用说明

• 一般情况下，Spring容器在启动时会创建所有的Bean对象，使用@Lazy注解可以将Bean对象的创建延迟到第一次使用Bean的时候

使用方法

1、@Lazy(value = true)：默认为true，不执行构造方法
2、@Lazy(value = false)：执行构造方法

将bean加载搭到spring容器的方式

• @Configuration +@bean

@Configuration
public class BeanConfig {@Bean@Lazy(value = true)public People people() {return new People();}
}

• @component

@Component
@Lazy(value = true)
public class Cat{public Cat() {System.out.println("#######小白猫#######);}
}

• @import

@Import(value = {Dog.class})@Lazy(value=false)
public class Dog{public Dog() {System.out.println("#######大黄狗#######);}
}

示例代码

1、不使用@lazy

/*** @author shuliangzhao* @Title: MyLazy* @ProjectName spring-boot-learn* @Description: TODO* @date 2019/10/10 19:27*/
@Component
public class MyLazy {public MyLazy() {System.out.println("懒加载...");}public void say() {System.out.println("say...");}
}

/*** @author shuliangzhao* @Title: LazyTest* @ProjectName spring-boot-learn* @Description: TODO* @date 2019/10/10 19:31*/
@RunWith(SpringRunner.class)
@SpringBootTest
public class LazyTest {@Autowiredprivate MyLazy myLazy;@Testpublic void test() {myLazy.say();}
}

执行结果：

2、使用lazy

/*** @author shuliangzhao* @Title: MyLazy* @ProjectName spring-boot-learn* @Description: TODO* @date 2019/10/10 19:27*/
@Component
@Lazy
public class MyLazy {public MyLazy() {System.out.println("懒加载...");}public void say() {System.out.println("say...");}
}

/*** @author shuliangzhao* @Title: LazyTest* @ProjectName spring-boot-learn* @Description: TODO* @date 2019/10/10 19:31*/
@RunWith(SpringRunner.class)
@SpringBootTest
public class LazyTest {@Autowiredprivate MyLazy myLazy;@Testpublic void test() {myLazy.say();}
}

执行结果：