三、 @Value获取值和@ConfigurationProperties获取值比较

前言：
1.@Value获取值和@ConfigurationProperties获取值比较

	@ConfigurationProperties	@Value
功能	批量注入配置文件中的属性	一个个指定
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

配置文件yml还是properties他们都能获取到值；

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；

——————————————————————————————————————
以下是实际的例子：
在application.properties中的配置如下：

person.last-name=李四
person.age=12
person.birth=2017/12/15
person.boss=false
person.maps.k1=v1
person.maps.k2=14
person.lists=a,b,c
person.dog.name=dog
person.dog.age=15

或者在application.yml中的配置如下：

person:
  last-name: jerry
  age: 20
  boss: true
  lists:
     - lisi
     - cao
  birth: 2017/12/12
  maps: {k1: v1,k2: 12}
  dog:
     name: hahah
     age: 30

上面两种方式任选其一即可：引用的方式如下两种：
1.在实体类上面加上如下主机
@Component// 将person加到容器中
@ConfigurationProperties(prefix = "person")

package com.flyz.entity;


import org.hibernate.validator.constraints.Email;
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.Null;
import java.util.Date;
import java.util.List;
import java.util.Map;


/**
* 将配置文件中配置的每一个属性的值，映射到这个组件中
* @ConfigurationProperties：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；
*      prefix = "person"：配置文件中哪个下面的所有属性进行一一映射
*
* 只有这个组件是容器中的组件，才能容器提供的@ConfigurationProperties功能；
*  @ConfigurationProperties(prefix = "person")默认从全局配置文件中获取值；
*
*/
//@PropertySource(value = {"classpath:person.properties"})
@Component// 将person加到容器中
@ConfigurationProperties(prefix = "person")
//@Validated
public class Person {

   /**
    * <bean class="Person">
    *      <property name="lastName" value="字面量/${key}从环境变量、配置文件中获取值/#{SpEL}"></property>
    * <bean/>
    */

  //lastName必须是邮箱格式
  // @Email
  // @Value("${person.last-name}")
   private String lastName;
  // @Value("#{11*2}")
   private Integer age;
 //   @Value("true")
   private Boolean boss;

   private Date birth;
   //@Value("${person.maps}")
   private Map<String,Object> maps;
   private List<Object> lists;
   private Dog dog;

   @Override
   public String toString() {
       return "Person{" +
               "lastName='" + lastName + '\'' +
               ", age=" + age +
               ", boss=" + boss +
               ", birth=" + birth +
               ", maps=" + maps +
               ", lists=" + lists +
               ", 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> getMaps() {
       return maps;
   }

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

   public List<Object> getLists() {
       return lists;
   }

   public void setLists(List<Object> lists) {
       this.lists = lists;
   }

   public Dog getDog() {
       return dog;
   }

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

使用 @Value注解

package com.flyz.entity;


import org.hibernate.validator.constraints.Email;
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.Null;
import java.util.Date;
import java.util.List;
import java.util.Map;


/**
 * 将配置文件中配置的每一个属性的值，映射到这个组件中
 * @ConfigurationProperties：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；
 *      prefix = "person"：配置文件中哪个下面的所有属性进行一一映射
 *
 * 只有这个组件是容器中的组件，才能容器提供的@ConfigurationProperties功能；
 *  @ConfigurationProperties(prefix = "person")默认从全局配置文件中获取值；
 *
 */
//@PropertySource(value = {"classpath:person.properties"})
@Component// 将person加到容器中
//@ConfigurationProperties(prefix = "person")
//@Validated
public class Person {

    /**
     * <bean class="Person">
     *      <property name="lastName" value="字面量/${key}从环境变量、配置文件中获取值/#{SpEL}"></property>
     * <bean/>
     */

   //lastName必须是邮箱格式
   // @Email
    @Value("${person.last-name}")
    private String lastName;
    @Value("#{11*2}")
    private Integer age;
    @Value("true")
    private Boolean boss;

    private Date birth;
    //@Value("${person.maps}")
    private Map<String,Object> maps;
    private List<Object> lists;
    private Dog dog;

    @Override
    public String toString() {
        return "Person{" +
                "lastName='" + lastName + '\'' +
                ", age=" + age +
                ", boss=" + boss +
                ", birth=" + birth +
                ", maps=" + maps +
                ", lists=" + lists +
                ", 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> getMaps() {
        return maps;
    }

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

    public List<Object> getLists() {
        return lists;
    }

    public void setLists(List<Object> lists) {
        this.lists = lists;
    }

    public Dog getDog() {
        return dog;
    }

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