进阶SpringBoot之 yaml 语法

SpringBoot 使用一个全局的配置文件，名字固定

application.properties  语法结构：key=value

application.yml  语法结构：key：（空格）value

配置文件的作用是可以修改 SpringBoot 自动配置的默认值

在 resources 目录下创建 application.yml

server:port: 8080

properties 只能保存键值对

yaml 对空格的要求非常严苛，并且 yaml 可以注入到配置类

举个例子

Dog.java：

package com.demo.helloworld.pojo;public class Dog {private String name;private Integer age;public Dog() {}public Dog(String name, Integer age) {this.name = name;this.age = age;}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;}@Overridepublic String toString() {return "Dog{" +"name='" + name + '\'' +", age=" + age +'}';}
}

Person.java：

@ConfigurationProperties 作用：

将配置文件中配置的每一个属性的值，映射到这个组件中

告诉 SpringBoot 将本类中的所有属性和配置文件中相关的配置进行绑定

参数 prefix = "person"  将配置文件中的 person 类下的所有属性一一对应

只有这个组件是容器中的组件，才能使用容器提供的 @ConfigurationProperties 功能

package com.demo.helloworld.pojo;import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;import java.util.Date;
import java.util.List;
import java.util.Map;@Component //注册bean
@ConfigurationProperties(prefix = "person") //配置类的值与配置文件绑定
public class Person {private String name;private Integer age;private Boolean happy;private Date birthday;private Map<String, Object> map;private List<Object> list;private Dog dog;public Person() {}public Person(String name, Integer age, Boolean happy, Date birthday, Map<String, Object> map, List<Object> list, Dog dog) {this.name = name;this.age = age;this.happy = happy;this.birthday = birthday;this.map = map;this.list = list;this.dog = dog;}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 Boolean getHappy() {return happy;}public void setHappy(Boolean happy) {this.happy = happy;}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<Object> getList() {return list;}public void setList(List<Object> list) {this.list = list;}public Dog getDog() {return dog;}public void setDog(Dog dog) {this.dog = dog;}@Overridepublic String toString() {return "Person{" +"name='" + name + '\'' +", age=" + age +", happy=" + happy +", birthday=" + birthday +", map=" + map +", list=" + list +", dog=" + dog +'}';}
}

application.yml：

person:name: 张三age: 18happy: truebirthday: 2024/8/1map: {k1: v1,k2: v2}list:- sing- dancedog:name: dogage: 1

测试类：

package com.demo.helloworld;import com.demo.helloworld.pojo.Person;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;//单元测试
@SpringBootTest
class HelloWorldApplicationTests {@Autowiredprivate Person person;@Testvoid contextLoads() {System.out.println(person);}}

也可以通过 @PropertySource(value = "classpath:xx.properties")  指定配置文件

//加载指定的配置文件
@PropertySource(value = "classpath:xx.properties")

但需要在属性上方或者 Set 方法上加 @Value 赋值

在 yaml 里可以随便使用占位符或者直接 ${random.uuid} 就能实现随机数