简单聊聊@ConfigurationProperties注解的使用以及与@Value注解的区别

╰半夏微凉° 2023-10-05 08:01 56阅读 0赞

### 用@ConfigurationProperties注解注入值； ###

1.  先创建Person实体类对象

public class Person {
        
        private String Name;
        private int id;
        private String [] family;
        private List list;//创建一个list集合
        private Map map;
        private Dog dog;//Dog类引用变量
        public Person() {
        
        }
    
        public Person(String name, int id, String[] family, List list, Map map, Dog dog) {
        
            Name = name;
            this.id = id;
            this.family = family;
            this.list = list;
            this.map = map;
            this.dog = dog;
        }
    
        public String getName() {
        
            return Name;
        }
    
        public void setName(String name) {
        
            Name = name;
        }
    
        public int getId() {
        
            return id;
        }
    
        public void setId(int id) {
        
            this.id = id;
        }
    
        public String[] getFamily() {
        
            return family;
        }
    
        public void setFamily(String[] family) {
        
            this.family = family;
        }
    
        public List getList() {
        
            return list;
        }
    
        public void setList(List list) {
        
            this.list = list;
        }
    
        public Map getMap() {
        
            return map;
        }
    
        public void setMap(Map map) {
        
            this.map = map;
        }
    
        public Dog getDog() {
        
            return dog;
        }
    
        public void setDog(Dog dog) {
        
            this.dog = dog;
        }
    
        @Override
        public String toString() {
        
            return "Person{" +
                    "Name='" + Name + '\'' +
                    ", id=" + id +
                    ", family=" + Arrays.toString(family) +
                    ", list=" + list +
                    ", map=" + map +
                    ", dog=" + dog +
                    '}';
        }
    }

2.创建Dog实体类

public class Dog {
        
        private String dogname;
        private int ID;
    
        public String getDogname() {
        
            return dogname;
        }
    
        public void setDogname(String dogname) {
        
            this.dogname = dogname;
        }
    
        public int getID() {
        
            return ID;
        }
    
        public void setID(int ID) {
        
            this.ID = ID;
        }
    
        @Override
        public String toString() {
        
            return "Dog{" +
                    "dogname='" + dogname + '\'' +
                    ", ID=" + ID +
                    '}';
        }
    }

3.这时候我们在Springboot核心配置文件application.yml中配置了相对应的属性值

person:
      Name:  yangzhongliang
      id:  1
      family:  [yangzhongliang,xiaogou,xiaozhu]
      list:  [shouji,diannao,shubao]
      map:  {
        k1:  v1 ,k2:  v2}
      dog: {
        dogname:  niuniu , ID: 2}

4.***这时候如果说我们Person实例对象想要批量注入属性，就可以使用我们的  
@ConfigurationProperties注解了。***

### 只需要在Person类上加上这两行注解。把Person类创建实例对象，然后把Springboot核心配置文件中的前缀为person的属性值传入到对象的属性中。 ###

注意:*(配置文件中的属性名称一定要和对象中的属性名称一致，因为底层是通过set方法注入的)*

@Component//把这个类生成实例对象加载到IOC容器中
    @ConfigurationProperties(prefix = "person")//意思是把Springboot的核心配置文件中前缀为Person的值注入到该类的属性中

### 测试: ###

@Autowired
        private Person person;
    
        //我们之前学习的@Value注解是spring的
    
        @Value("${person.Name}")//使用Spring的spel表达式，调用Springboot配置文件中的Name属性值
        private String Chinaname;
    
    
        @Test
        public void Test1(){
        
            System.out.println(person);
            System.out.println(Chinaname);
        }

### 输出结果: ###

![在这里插入图片描述][20200809230948807.png]

## 那@ConfigurationProperties注解又与我们在Spring中学习到的@Value注解有什么区别呢？ ##

**他们的区别就在下面:**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ1OTc5NjI5_size_16_color_FFFFFF_t_70]  
**举个实例，例如JSR303校验，我们可以通过@ConfigurationProperties注解来进行一个演示:**  
1.我们先创建一个实体类

public class MyEmail {
        
    private String Email;
    
        public String getEmail() {
        
            return Email;
        }
    
        public void setEmail(String email) {
        
            Email = email;
        }
    
        @Override
        public String toString() {
        
            return "MyEmail{" +
                    "Email='" + Email + '\'' +
                    '}';
        }
    }

2.在Springboot核心配置文件中配置相对应的属性值

myemail:
      email:  lisi

3.这时候我们使用@ConfigurationProperties进行注入，给类上加上  
@ConfigurationProperties注解。

@Component
    @ConfigurationProperties(prefix = "myemail")

4.测试类：

@Autowired
        private MyEmail myEmail;
        @Test
        public void Test2(){
        
            System.out.println(myEmail.getEmail());
        }

5.打印输出:  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ1OTc5NjI5_size_16_color_FFFFFF_t_70 1]正常注入成功并打印在控制台，**但是如果我们使用JSR303数据校验，给MyEmail类上加上@Validated注解，并给变量Email属性设置@Email注解，使变量必须注入邮箱格式的属性值。**

@Component
    @ConfigurationProperties(prefix = "myemail")
    @Validated//JSR303数据校验注解
    public class MyEmail {
        
        @Email//使用@Email注解标注这个属性中的值必须为邮件格式
        private String Email;
    
        public String getEmail() {
        
            return Email;
        }
    
        public void setEmail(String email) {
        
            Email = email;
        }
    
        @Override
        public String toString() {
        
            return "MyEmail{" +
                    "Email='" + Email + '\'' +
                    '}';
        }
    }

这时候如果输出，会发现报错了。

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ1OTc5NjI5_size_16_color_FFFFFF_t_70 2]  
如果这时候把核心配置文件中的属性值修改成邮箱格式。

myemail:
      email:  lisi@163.com

再次测试:  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQ1OTc5NjI5_size_16_color_FFFFFF_t_70 3]

**这时候成功在控制台中打印出来了。。。。。。。。。。。。。。。。。**

[20200809230948807.png]: https://img-blog.csdnimg.cn/20200809230948807.png
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