第二篇：Spring Boot配置文件详解

SpringBoot使用一个全局的配置文件，配置文件名的

• application.properties
• application.yml

配置文件的作用 : SpringBoot底层都给我们配置好了，但有时候我们需要修改一些默认配置。

一、YMAL

1. YMAL与XML对比

YMAL :

server
  port: 8081

XML :

<server>
    <port>8081</port>
</server>

2. 基本语法

k:空格v : 表示一对键值对（空格必须有)
以空格的缩进来控制层级关系；空格多少无所谓，只要左对齐的一列数据，都是同一个层级的。

server:
    port: 8081
    path: /hello

3. 配置文件值注入

application.yml

server:
  port: 8081

person:
  lastName: zhangsan # 也可写成(松散语法) last-name:zhansang
  age: 18
  boss: false
  birth: 2017/12/12
  map: {k1: v1, k2 : 12}
  list:
    - lisi
    - zhaoliu
  dog:
    name: 史努比
    age: 2
cat:
  name: Tom
  age: 5

实体类 Person

package com.gf.entity;


import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

import java.util.Date;
import java.util.List;
import java.util.Map;

/**
 * 将配置文件中的配置，映射到这个组件中
 * @ConfigurationProperties: 告诉SpringBoot将本类所有属性和配置文件中相关的配置进行绑定
 *      prefix = "person" : 配置文件中那个下面的所有属性进行一一映射
 * 只有这个这个组件是容器中的组件，才能使用容器提供的@ConfigurationProperties的功能
 */
@Component
@ConfigurationProperties(prefix = "person")
public class Person {
    private String lastName;
    private Integer age;
    private Boolean boss;
    private Date birth;

    private Map<String , Object> map;
    private List<Object> list;
    private Dog dog;

    public String getLastName() {
        return lastName;
    }

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

    public Integer getAge() {
        return age;
    }

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

    public Boolean getBoss() {
        return boss;
    }

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

    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 Dog getDog() {
        return dog;
    }

    public void setDog(Dog dog) {
        this.dog = dog;
    }

    @Override
    public String toString() {
        final StringBuilder sb = new StringBuilder( "{\"Person\":{" );
        sb.append( "\"lastName\":\"" )
                .append( lastName ).append( '\"' );
        sb.append( ",\"age\":" )
                .append( age );
        sb.append( ",\"boss\":" )
                .append( boss );
        sb.append( ",\"birth\":\"" )
                .append( birth ).append( '\"' );
        sb.append( ",\"map\":" )
                .append( map );
        sb.append( ",\"list\":" )
                .append( list );
        sb.append( ",\"dog\":" )
                .append( dog );
        sb.append( "}}" );
        return sb.toString();
    }
}

实体类 Dog

package com.gf.entity;


public class Dog {

    private String name;
    private Integer 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() {
        final StringBuilder sb = new StringBuilder( "{\"Dog\":{" );
        sb.append( "\"name\":\"" )
                .append( name ).append( '\"' );
        sb.append( ",\"age\":" )
                .append( age );
        sb.append( "}}" );
        return sb.toString();
    }
}

实体类 Cat

package com.gf.entity;

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

@Component
public class Cat {
    @Value( "${cat.name}" )
    private String name;
    @Value( "${cat.age}" )
    private Integer 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() {
        final StringBuilder sb = new StringBuilder( "{\"Cat\":{" );
        sb.append( "\"name\":\"" )
                .append( name ).append( '\"' );
        sb.append( ",\"age\":" )
                .append( age );
        sb.append( "}}" );
        return sb.toString();
    }
}

pom.xml

<?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.gf</groupId>
    <artifactId>springboot-config</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>springboot-config</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.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>
        <!-- 导入配置文件处理器，配置文件进行绑定就会有提示 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>

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


</project>

SpringBoot 测试类

package com.gf;

import com.gf.entity.Cat;
import com.gf.entity.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.test.context.junit4.SpringRunner;

/**
 * SpringBoot单元测试
 * 可以在测试期间很方便的类似编码一样进行自动注入等容器的功能
 */
@RunWith(SpringRunner.class)
@SpringBootTest
public class SpringbootConfigApplicationTests {

    @Autowired
    Person person;

    @Autowired
    Cat cat;

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

}

运行 SpringbootConfigApplicationTests 的到结果

{
    "Person": {
        "lastName": "zhangsan",
        "age": 18,
        "boss": false,
        "birth": "Tue Dec 12 00:00:00 CST 2017",
        "map": {
            k1 = v1,
            k2 = 12
        },
        "list": [lisi, zhaoliu],
        "dog": {
            "Dog": {
                "name": "史努比",
                "age": 2
            }
        }
    }
} 
{
    "Cat": {
        "name": "Tom",
        "age": 5
    }
}

@Value获取值和@ConfigurationProperties获取值比较

	@ConfigurationProperties	@Value
功能	批量注入文件中的属性	一个一个指定
松散绑定（松散语法）	支持	不支持
SpEL	不支持	支持
JSR303数据校验	支持	不支持
复杂类型封装	支持	不支持

如果说，我们只是在某个业务逻辑中需要获取一下配置文件中的某项值，使用@Value;
如果说，我们专门编写了一个javaBean来和配置文件进行映射，我们就直接使用@ConfigurationProperties;