详解Spring注解驱动开发之属性赋值

public class Person {
    
    @Value("#{20-2}")     //SpEL表达式 #{}
    private Integer id;
    
    @Value("张三")        //基本数据类型
    private String name;
}

@Configuration
public class MainConfiGofPropertyValues {

    @Bean
    public Person person(){
        return new Person();
    }
}

 @Test
    public void testValues(){
        ApplicationContext context = new AnnotationConfigApplicationContext(MainConfigOfPropertyValues.class);

        String[] beanDefinitionNames = context.getBeanDefinitionNames();

        for (String beanName : beanDefinitionNames){
            System.out.println(beanName);
        }

        Person person = (Person) context.getBean("person");

        System.out.println(person);
    }

@PropertySource({"classpath:/person.properties"})
@Configuration
public class MainConfigOfPropertyValues {

    @Bean
    public Person person(){
        return new Person();
    }
}

public class Person {

    @Value("#{20-2}")     //SpEL表达式 #{}
    private Integer id;

    @Value("张三")        //基本数据类型
    private String name;
    
    @Value("${person.age}")     //使用外部配置文件注入属性值
    private Integer age;
}

 @Test
    public void testValues(){
        ApplicationContext context = new AnnotationConfigApplicationContext(MainConfigOfPropertyValues.class);

        String[] beanDefinitionNames = context.getBeanDefinitionNames();

        for (String beanName : beanDefinitionNames){
            System.out.println(beanName);
        }

        Person person = (Person) context.getBean("person");

        System.out.println(person);

        Environment environment = context.getEnvironment();

        String age = environment.getProperty("person.age");
        System.out.println("age = " + age);

    }