12、spring注解学习（属性赋值）——@PropertySource加载外部配置文件

1、创建person类

public class Person {

    /*
     * 使用@Value赋值：
     *     1、基本数值
     *     2、可以写SpEl；#{}
     *     3、可以写${}、取出配置文件中(例如properties文件)的值（运行环境变量里面的值）
     */
    @Value("张三")
    private String name;
    @Value("#{20-2}")
    private Integer age;

    private String school;

    public Person() {
        super();
    }
    public Person(String name, Integer age) {
        super();
        this.name = name;
        this.age = age;
    }
    public String getName() {
        return name;
    }
    public Integer getAge() {
        return age;
    }
    public void setName(String name) {
        this.name = name;
    }
    public void setAge(Integer age) {
        this.age = age;
    }

    public String getSchool() {
        return school;
    }
    public void setSchool(String school) {
        this.school = school;
    }
    @Override
    public String toString() {
        return "Person [name=" + name + ", age=" + age + ", school=" + school + "]";
    }
}

2、创建要加载的外部文件

3、spring配置类中加载外部配置文件

/**
 * 测试bean的属性赋值的配置
 */
@Configuration
@PropertySource(value= {"classpath:/person.properties"})
public class MainConfigOfPropertyValue {

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

4、在person类中的属性赋外部文件中定义的值

public class Person {

    /*
     * 使用@Value赋值：
     *     1、基本数值
     *     2、可以写SpEl；#{}
     *     3、可以写${}、取出配置文件中(例如properties文件)的值（运行环境变量里面的值）
     */
    @Value("张三")
    private String name;
    @Value("#{20-2}")
    private Integer age;

    @Value("${person.school}")
    private String school;
    public Person() {
        super();
    }
    public Person(String name, Integer age) {
        super();
        this.name = name;
        this.age = age;
    }
    public String getName() {
        return name;
    }
    public Integer getAge() {
        return age;
    }
    public void setName(String name) {
        this.name = name;
    }
    public void setAge(Integer age) {
        this.age = age;
    }

    public String getSchool() {
        return school;
    }
    public void setSchool(String school) {
        this.school = school;
    }
    @Override
    public String toString() {
        return "Person [name=" + name + ", age=" + age + ", school=" + school + "]";
    }
}

5、定义测试方法进行测试

    @Test
    public void test01() {
        AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(MainConfigOfPropertyValue.class);
        Object bean = applicationContext.getBean("person");
        System.out.println(bean);
    }

得到结果：

 外部文件赋值成功。