Spring boot @Value获取值和@ConfigurationProperties获取值比较

女爷i 2022-03-29 13:54 296阅读 0赞

## 一.@Value获取值和@ConfigurationProperties获取值比较 ##

<table> 
 <tbody> 
  <tr> 
   <td style="width:192px;">&nbsp;</td> 
   <td style="width:257px;"><em><strong>@ConfigurationProperties</strong></em></td> 
   <td style="width:434px;"><em><strong>@Value</strong></em></td> 
  </tr> 
  <tr> 
   <td style="width:192px;">功能 &nbsp;</td> 
   <td style="width:257px;">批量注入配置文件中的属性</td> 
   <td style="width:434px;">一个个指定</td> 
  </tr> 
  <tr> 
   <td style="width:192px;">松散绑定（松散语法）</td> 
   <td style="width:257px;">支持</td> 
   <td style="width:434px;">不支持</td> 
  </tr> 
  <tr> 
   <td style="width:192px;">SpEL</td> 
   <td style="width:257px;">支持&nbsp;</td> 
   <td style="width:434px;">不支持</td> 
  </tr> 
  <tr> 
   <td style="width:192px;">JSR303数据校验</td> 
   <td style="width:257px;">支持&nbsp;</td> 
   <td style="width:434px;">不支持</td> 
  </tr> 
 </tbody> 
</table>

## 二.举例对比 ##

**@ConfigurationPropertie：**

配置文件application.properties

person.last-name=张三
    person.age=18
    person.birth=2019/01/07
    person.boss=true
    person.maps.k1=v1
    person.maps.k2=15
    person.lists=a,b,c
    person.dog.name=小狗
    person.dog.age=5

实体类Person

@Component
    @ConfigurationProperties(prefix = "person")
    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;
    
        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;
        }
    
        @Override
        public String toString() {
            return "Person{" +
                    "lastName='" + lastName + '\'' +
                    ", age=" + age +
                    ", boss=" + boss +
                    ", birth=" + birth +
                    ", maps=" + maps +
                    ", lists=" + lists +
                    ", dog=" + dog +
                    '}';
        }

测试类 SpringBoot02ConfigApplicationTests

@RunWith(SpringRunner.class)
    @SpringBootTest
    public class SpringBoot02ConfigApplicationTests {
        @Autowired
        Person person;
        @Test
        public void contextLoads() {
            System.out.println(person);
        }
    
    }

运行结果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3htMzkzMzkyNjI1_size_16_color_FFFFFF_t_70][]

**@Value：**

实体类Person(省略get、set、toString方法)

@Component
    public class Person {
        /*相当于spring中
         *<bean class="Person">
         *      <property name="lastName" value="字面量/${key}从环境变量、配置文件中获取值/#{SpEL}"></property>
         * <bean/>
         */
        @Value("${person.last-name}")
        private String lastName;
        @Value("#{10*2}")
        private Integer age;
        @Value("true")
        private Boolean boss;
        private Date birth;
        private Map<String,Object> maps;
        private List<Object> lists;
        private Dog dog;
    
        ...get set toString
    }

运行结果：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3htMzkzMzkyNjI1_size_16_color_FFFFFF_t_70 1][]

不支持Map，List等复杂类型，例如

@Value("${person.maps}")//不支持map
    private Map<String,Object> maps;

不支持校验，例如

@Component
    @Validated//该校验无效
    public class Person {
     
        @Email
        @Value("${person.last-name}")
        private String lastName;
    }

## 三.总结： ##

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；

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