02、@PropertySource指定配置文件的属性映射到JavaBean属性

零、@PropertySource 功能类似于

<context:property-placeholder location="classpath*:/config/load.properties"/>

@Configuration
@PropertySources(
        @PropertySource(value = "classpath:/config/load.properties",ignoreResourceNotFound = true,encoding = "UTF-8")
)
public class ServerProperties {
    @Value("${liubin.test.name}")
    private String name;

    public String getName() {
        return name;
    }
}

一、引入配置文件注解PropertySource源码

package org.springframework.context.annotation;

import ....;

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

    String[] value();//可以是多个

    boolean ignoreResourceNotFound() default false;

    String encoding() default "";

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

二、PropertySources中包含多个PropertySource

package org.springframework.context.annotation;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface PropertySources {
    PropertySource[] value();
}

三、引入配置文件后配置项被@Value注解使用

@Component
@PropertySource("classpath:teacher.properties")
public class Student {

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

    @Value("${age}")
    private int age;

    @Value("${sex}")
    private String sex;

    @Value("${height}")
    private int height;

    @Value("${weight}")
    private int weight;
}

四、引入配置文件后配置项被Spring Boot 的@ConfigurationProperties使用，一站式注入到相应的JavaBean的所有属性中

@PropertySource({"classpath:teacher.properties"})　//指定某配置文件，无此参数则在默认全局配置文件中获取
@Component
@ConfigurationProperties(prifix=“teacher”) //配置文件中前缀名为teacher的配置项的所有属性都映射到此JavaBean中
public class Teacher {
    private String name;

    private int age;

    private String sex;

    private int height;

    private int weight;

　　get\set方法
}

五、不同的属性配置文件中若有相同的配置项，写在后面配置文件中的属性覆盖前面的

@PropertySources(
    {
        @PropertySource("classpath:teacher.properties")
    }
)