@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 {

    @Autowired
    private MyLazy myLazy;

    @Test
    public 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 {

    @Autowired
    private MyLazy myLazy;

    @Test
    public void test() {
         myLazy.say();
    }
}

执行结果：