一、为什么需要加载局部配置文件

使用 @Value 或 @ConfigurationProperties 为属性注入配置文件中的值时，默认是去全局配置文件（application.properties 或 application.yml）去寻找对应的值。

但是如果都将配置放入该文件，不方便找到，所以可以使用局部配置文件。

在类上使用 @PropertySource 指定对应的局部配置文件，即可读入局部配置文件的配置。

@PropertySource(value = {"配置文件位置"})

可同时制定多个配置文件，在 {} 中使用逗号（，）隔开即可。

二、加载局部配置文件示范

1、新建局部配置文件

在 src/main/resources 下新建局部配置文件 demo.properties

# 配置 demo 的值
demo.last-name=lisi
demo.age=30
demo.birthday=1989/9/12
demo.boss=false
demo.salary=23000
demo.map.key1=value1
demo.map.key2=value2
demo.list=one, two, three
demo.data-demo.name=zhangsan
demo.data-demo.age=20

2、在类上加上 @PropertySource，并指定局部配置文件的位置

package com.example.springbootboot02config.bean;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.PropertySource;
import org.springframework.stereotype.Component;
import org.springframework.validation.annotation.Validated;

import javax.validation.constraints.Email;
import java.util.Date;
import java.util.List;
import java.util.Map;

/**
 * @author liyanan
 * @date 2019/12/16 13:43
 */

@PropertySource(value = {"classpath:demo.properties"})      // 加载局部配置文件
@ConfigurationProperties(prefix = "demo")
@Component
@Validated
public class Demo {

    private String lastName;

    private Integer age;
    
    private Double salary;

    private Boolean boss;

    private Date birthday;

    private Map<String, Object> map;

    private List<String> list;

    private DataDemo dataDemo;

    private static String config;


    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public Integer getAge() {
        return age;
    }

    public void setConfig(String config) {
        Demo.config = config;
    }

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

    public Double getSalary() {
        return salary;
    }

    public void setSalary(Double salary) {
        this.salary = salary;
    }

    public Boolean getBoss() {
        return boss;
    }

    public void setBoss(Boolean boss) {
        this.boss = boss;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    public Map<String, Object> getMap() {
        return map;
    }

    public void setMap(Map<String, Object> map) {
        this.map = map;
    }

    public List<String> getList() {
        return list;
    }

    public void setList(List<String> list) {
        this.list = list;
    }

    public DataDemo getDataDemo() {
        return dataDemo;
    }

    public void setDataDemo(DataDemo dataDemo) {
        this.dataDemo = dataDemo;
    }

    public static String getConfig() {
        return config;
    }

    @Override
    public String toString() {
        return "Demo{" +
                "lastName='" + lastName + '\'' +
                ", age=" + age +
                ", salary=" + salary +
                ", boss=" + boss +
                ", birthday=" + birthday +
                ", map=" + map +
                ", list=" + list +
                ", dataDemo=" + dataDemo +
                '}';
    }
}

3、测试是否注入成功

package com.example.springbootboot02config;

import com.example.springbootboot02config.bean.Demo;
import com.example.springbootboot02config.bean.Emp;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
class SpringbootBoot02ConfigApplicationTests {

    @Autowired
    Demo demo;

    @Test
    void contextLoads() {
        System.out.println(demo);
    }

}

运行结果为：

Demo{lastName='lisi', age=30, salary=23000.0, boss=false, birthday=Tue Sep 12 00:00:00 CDT 1989, map={key2=value2, key1=value1}, list=[one, two, three], dataDemo=DataDemo{name='zhangsan', age=20}}