spring boot 中获取配置文件值

 

@Value 使用  

1. 导入配置文件 然后根据名称用$进行赋值

@Configuration
@ImportResource("classpath:/com/acme/properties-config.xml")
public class AppConfig {

    @Value("${jdbc.url}")
    private String url;

    @Value("${jdbc.username}")
    private String username;

    @Value("${jdbc.password}")
    private String password;

    @Bean
    public DataSource dataSource() {
        return new DriverManagerDataSource(url, username, password);
    }
}

 2. 用# 来获取已经存在的值，就是spring 会存储获取值的那个实列。

 

@Component
public class FactoryMethodComponent {

    private static int i;

    @Bean
    @Qualifier("public")
    public TestBean publicInstance() {
        return new TestBean("publicInstance");
    }

    // use of a custom qualifier and autowiring of method parameters
    @Bean
    protected TestBean protectedInstance(
            @Qualifier("public") TestBean spouse,
            @Value("#{privateInstance.age}") String country) {
        TestBean tb = new TestBean("protectedInstance", 1);
        tb.setSpouse(spouse);
        tb.setCountry(country);
        return tb;
    }

    @Bean
    private TestBean privateInstance() {
        return new TestBean("privateInstance", i++);
    }

    @Bean
    @RequestScope
    public TestBean requestScopedInstance() {
        return new TestBean("requestScopedInstance", 3);
    }
}

@ConfigurationProperties 的使用

@ConfigurationProperties(prefix="acme.my-project.person")
public class OwnerProperties {

	private String firstName;

	public String getFirstName() {
		return this.firstName;
	}

	public void setFirstName(String firstName) {
		this.firstName = firstName;
	}

}

@ConfigurationProperties  支持 relaxed binding.

Property	Note
acme.my-project.person.first-name	Kebab case, which is recommended for use in .properties and .yml files.
acme.myProject.person.firstName	Standard camel case syntax.
acme.my_project.person.first_name	Underscore notation, which is an alternative format for use in .properties and .yml files.
ACME_MYPROJECT_PERSON_FIRSTNAME	Upper case format, which is recommended when using system environment variables.

 @ConfigurationProperties vs. @Value

The @Value annotation is a core container feature, and it does not provide the same features as type-safe configuration properties. The following table summarizes the features that are supported by @ConfigurationProperties and @Value:

Feature	@ConfigurationProperties	@Value
Relaxed binding	Yes	No
Meta-data support	Yes	No
SpEL evaluation	No	Yes