yml loads configuration information through the way of @ ConfigurationProperties and @ value

1. There are two ways to bind values:

• @ConfigurationProperties
• @Value

1. Priority: if you mix @ ConfigurationProperties, the priority is higher than @ value, but they can complement each other;
2. @The data of ConfigurationProperties comes from application.properties and application.yml files;

The @ Value data is write dead, which is not related to the configuration file;

@ configurationproperties supports batch loading / injection, @ Value single injection;

4. Loose syntax: (user name > user name (in the form of hump)

@ ConfigurationProperties is supported; @ Value is not supported;

      5. SpEL:

@ ConfigurationProperties is not supported, @ value is supported;

6. JSR303 data verification:

@ ConfigurationProperties is supported; @ Value is not supported;

7. Inject complex type

@ ConfigurationProperties supports, @ Value does not;

II @ PropertySource:

1. By default, the data in the application.yml and applicationton.properties files will be loaded. If the data is not in these two files, you need to specify it through this annotation: @ PropertySource("classpath:user.properties");
2. @The PropertySource annotation can only load properties files, but not yml files;
3. Load the specified properties file (*. properties) into the Spring container. You can use @ PropertySource with @ Value and @ ConfigurationProperties;

• The combination of @ PropertySource and @ Value can inject the Value of the property variable in the custom property file into the member variable of the current class annotated with @ Value.
• The combination of @ PropertySource and @ ConfigurationProperties can bind the property file to a Java class and inject the variable values in the property file into the member variables of the Java class.

Source code

package org.springframework.context.annotation;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Repeatable;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.springframework.core.io.support.PropertySourceFactory;

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Repeatable(PropertySources.class)
public @interface PropertySource {
    String name() default "";

    String[] value();

    boolean ignoreResourceNotFound() default false;

    String encoding() default "";

    Class<? extends PropertySourceFactory> factory() default PropertySourceFactory.class;
}

Using examples

Create user.properties under project and path

Properties file user.properties

user.name=jacklin
user.age=22
user.job=IT
user.email=793066408@qq.com

Demo 1: @ PropertySource and @ Value

/**
 * @Author Lin Bi Zhao
 * @Date 2019/11/28 16:28
 * @descr
 */

@Component
@PropertySource(value = "classpath:user.properties")
public class ReadUserByPropertySourceValue {

    @Value("${user.name}")
    private String name;

    @Value("${user.age}")
    private Integer age;

    @Value("${user.job}")
    private String job;

    @Value("${user.email}")
    private String email;

    @Override
    public String toString() {
        return "ReadUserByPropertySourceValue{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", job='" + job + '\'' +
                ", email='" + email + '\'' +
                '}';
    }
}

Example 2: @ PropertySource and @ ConfigurationProperties

@Component
@PropertySource(value = {"classpath:user.properties"})
@ConfigurationProperties(prefix = "user")
public class ReadUserByPropertySourceAndConfigurationProperties {

    private String name;
    private Integer age;
    private String job;
    private String email;

    public String getName() { return name; }

    public void setName(String name) { this.name = name; }

    public Integer getAge() { return age; }

    public void setAge(Integer age) { this.age = age; }

    public String getJob() { return job; }

    public void setJob(String job) { this.job = job; }

    public String getEmail() { return email; }

    public void setEmail(String email) { this.email = email;}

    @Override
    public String toString() {
        return "ReadUserByPropertySourceAndConfigurationProperties{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", job='" + job + '\'' +
                ", email='" + email + '\'' +
                '}';
    }
}

Test example

@Slf4j
@SpringBootApplication
public class SpringPropertiesInjectionDemoApplication implements CommandLineRunner {

    @Autowired
    private ReadUserByPropertySourceValue readUserByPropertySourceValue;

    @Autowired
    private ReadUserByPropertySourceAndConfigurationProperties readUserByPropertySourceAndConfigurationProperties;


    public static void main(String[] args) {
        SpringApplication.run(SpringPropertiesInjectionDemoApplication.class, args);
    }

    @Override
    public void run(String... args) throws Exception {
        log.info(readUserByPropertySourceValue.toString());
        log.info(readUserByPropertySourceAndConfigurationProperties.toString());
    }
}

Start project observation console log printout: