springboot的yaml基礎語法與取值,配置類,配置文件加載優先級

一、基本語法
k:(空格)v:表示一對鍵值對(一個空格必須有);
以空格的縮進來控制層級關係;只要是左對齊的一列數據,都是同一個層級的
屬性和值也是大小寫敏感;java

server:
    port: 8081
    path: /hello

二、值的寫法
字面量:web

普通的值(數字,字符串,布爾)
k: v:字面直接來寫;
字符串:spring

默認不用加上單引號或者雙引號;
"":雙引號;不會轉義字符串裏面的特殊字符;特殊字符會做爲自己想表示的意思
name: "zhangsan \n lisi":輸出;zhangsan 換行 lisi
'':單引號;會轉義特殊字符,特殊字符最終只是一個普通的字符串數據
name: ‘zhangsan \n lisi’:輸出;zhangsan \n lisiapache

對象、Map(屬性和值)(鍵值對):
k: v:在下一行來寫對象的屬性和值的關係;注意縮進
對象仍是k: v的方式
數組

friends:
    lastName: zhangsan
    age: 20

行內寫法:springboot

friends: {lastName: zhangsan,age: 18}

數組(List、Set):
用- 值表示數組中的一個元素app

pets:
 ‐ cat
 ‐ dog
 ‐ pig

行內寫法:dom

pets: [cat,dog,pig]

 3.springboot配置類maven

3.1pom文件spring-boot

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.zy</groupId>
    <artifactId>spring-boot-yaml-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>spring-boot-yaml-demo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.14.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.20</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>

        <dependency>
            <groupId>com.netflix.archaius</groupId>
            <artifactId>archaius-core</artifactId>
            <version>0.7.6</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>

3.2實體類

package com.zy.model;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
public class Cat {

    private String name;

    private Integer age;

}

3.3配置類

package com.zy.config;

import com.zy.model.Cat;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MyConfigBean {

    @Bean
    //將方法的返回值添加到容器中;容器中這個組件默認的id就是方法名
    public Cat getCat(){
        return new Cat("tom",20);
    }
}

3.4得到bean

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringBootYamlDemoApplicationTests {

    @Autowired
    private ApplicationContext applicationContext;   

    @Test
    public void fn(){
        Cat cat = (Cat) applicationContext.getBean("getCat");
        System.out.println(cat);
    }

}

4.springboot取yaml中的值(在上述代碼基礎上)

package com.zy.model;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.List;
import java.util.Map;
@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
@Component
//@PropertySource(value = {"classpath:person.properties"}) 另外一種配置方式
@ConfigurationProperties(prefix = "person") // 該prefix對應於yaml文件中的person
/**
 * 將配置文件中配置的每個屬性的值,映射到這個組件中
 * @ConfigurationProperties:告訴SpringBoot將本類中的全部屬性和配置文件中相關的配置進行綁定;
 *      prefix = "person":配置文件中哪一個下面的全部屬性進行一一映射
 *
 * 只有這個組件是容器中的組件,才能容器提供的@ConfigurationProperties功能;
 *  @ConfigurationProperties(prefix = "person")默認從全局配置文件中獲取值;
 *
 */
public class Person {

    private String lastName;

    private Integer age;

    private Boolean boss;

    private Date birth;

    private Map<String,Object> maps;

    private List<Object> lists;

    private Dog dog;

}
package com.zy.model;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
@Component
@ConfigurationProperties(prefix = "dog") // 該prefix對應於yaml文件中的dog
public class Dog {

    private String name;

    private Integer age;

}
server:
  port: 8080
person:
  lastName: 張三
  age: 20
  boss: false
  birth: 1999/09/09
  maps: {k1: v1,k2: v2}
  lists:
    - z1
    - z2
    - z3
  dog:
    name: little dog
    age: 2
package com.zy;

import com.zy.model.Cat;
import com.zy.model.Person;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.context.ApplicationContext;
import org.springframework.test.context.junit4.SpringRunner;

@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringBootYamlDemoApplicationTests {

    @Autowired
    private Person person;

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

}

5.springboot配置文件加載優先級

7.外部配置加載順序
SpringBoot也能夠從如下位置加載配置; 優先級從高到低;高優先級的配置覆蓋低優先級的配置,全部的配置會
造成互補配置
7.1.命令行參數
全部的配置均可以在命令行上進行指定
java -jar spring-boot-02-config-02-0.0.1-SNAPSHOT.jar --server.port=8087 --server.context-path=/abc
多個配置用空格分開; --配置項=值
7.2.來自java:comp/env的JNDI屬性
7.3.Java系統屬性(System.getProperties())
7.4.操做系統環境變量
7.5.RandomValuePropertySource配置的random.*屬性值
由jar包外向jar包內進行尋找;
優先加載帶profile
7.6.jar包外部的application-{profile}.properties或application.yml(帶spring.profile)配置文件
7.7.jar包內部的application-{profile}.properties或application.yml(帶spring.profile)配置文件
再來加載不帶profile7.8.jar包外部的application.properties或application.yml(不帶spring.profile)配置文件7.9.jar包內部的application.properties或application.yml(不帶spring.profile)配置文件7.10.@Configuration註解類上的@PropertySource7.11.經過SpringApplication.setDefaultProperties指定的默認屬性全部支持的配置加載來源;

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