Spring配置元数据的三种方式

1. 基于java配置方式

@Configuration
public class BeanConfiguration {

    @Bean
    public Account account(){
        return new Account("001001001");
    }

    @Bean
    public User user(Account account){
        return new User("张三",18,account);
    }

    @Bean
    public User userNoAccount(){
        return new User("张三",18,null);
    }
}

2. 基于注解方式

@Repository
public class JpaMovieFinder implements MovieFinder {
    // implementation elided for clarity
}

@Service
public class SimpleMovieLister {

    private MovieFinder movieFinder;

    public SimpleMovieLister(MovieFinder movieFinder) {
        this.movieFinder = movieFinder;
    }
}

3. 基于xml方式

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
        https://www.springframework.org/schema/beans/spring-beans.xsd">

    <!--  空值的user  -->
    <bean id="userNoValue" class="intron.spring.entity.User"></bean>

    <!--  带值的user  -->
    <bean id="user" class="intron.spring.entity.User">
        <property name="name" value="张三"></property>
        <property name="age" value="18"></property>
    </bean>

    <!--  全参构造，使用成员属性索引对应  -->
    <bean id="userOnIndex" class="intron.spring.entity.User">
        <constructor-arg index="0" value="张三"></constructor-arg>
        <constructor-arg index="1" value="18"></constructor-arg>
    </bean>

    <!--  全参构造，使用成员属性类型对应  -->
    <bean id="userOnType" class="intron.spring.entity.User">
        <constructor-arg type="java.lang.String" value="张三"></constructor-arg>
        <constructor-arg type="int" value="18"></constructor-arg>
    </bean>

</beans>