SpringBoot配置文件

官方提供两种配置文件分别是application.properties与application.yaml文件

application.properties文件语法结构为key=value

例 : server.port=8080

存对象

student.name=zhangsan

student.age=3

application.yaml文件语法结构为key:空格value

例 ：

server:
  port: 8080

存对象

student:
  name: zhangsan
  age: 3

行内写法

对象：

student: {name: zhangsan,age: 3}

数组

arrar:
  -a
  -b
  -c

或者 array: [a,b,c] 而properties只能存键值对但是yaml对空格的要求非常高！

但是yaml可以给实体类赋值

实例：Cat实体类

import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component
public class Cat {
    @Value("招财")
    private String name;
    @Value("1")
    private Integer age;

    public Cat() {
    }

    public Cat(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;
    }

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

porple实体类

@CoanficqurationPrepertiea作用:
将配置文件中配置的每一个屈性的值，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管进行绑定
参数 prcfix - "people”:将配置文件中的people下面的所有属性一 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@ConfiqurationPrcpertiea功能

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
@ConfigurationProperties(prefix = "people")
public class People {
    private String name;
    private Integer age;
    private boolean happy;
    private Date birth;
    private Map<String,Object> map;
    private List<Object> list;
    private Cat cat;

    public People() {
    }

    public People(String name, Integer age, boolean happy, Date birth, Map<String, Object> map, List<Object> list, Cat cat) {
        this.name = name;
        this.age = age;
        this.happy = happy;
        this.birth = birth;
        this.map = map;
        this.list = list;
        this.cat = cat;
    }

    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 isHappy() {
        return happy;
    }

    public void setHappy(boolean happy) {
        this.happy = happy;
    }

    public Date getBirth() {
        return birth;
    }

    public void setBirth(Date birth) {
        this.birth = birth;
    }

    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 Cat getCat() {
        return cat;
    }

    public void setCat(Cat cat) {
        this.cat = cat;
    }

    @Override
    public String toString() {
        return "People{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", happy=" + happy +
                ", birth=" + birth +
                ", map=" + map +
                ", list=" + list +
                ", cat=" + cat +
                '}';
    }
}

application.yaml配置文件注意 application.yaml中的字段名对应实体类的列名

people:
  name: zhangsan
  age: 13
  happy: true
  birth: 2022/3/25
  map: {aa: a,bb: b,cc: c}
  list: [a,b,c,d,e,f]
  cat:
    name: zhaocai
    age: 3

使用xx.properties文件可以通过类名上使用 @PropertySource("classpath:xx.properties")

通过列名上使用@Value("${xxx}")来进行赋值也就是SPEL表达式

配置文件作用：修改SpringBoot自动配置的默认值,因为SpringBoot在底层自动配置好了