SpringBoot注入配置文件的3种方法

方案1:@ConfigurationProperties+@Component

 定义spring的一个实体bean装载配置文件信息，其它要使用配置信息是注入该实体bean

 /**
  * 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；
  *
  */
 @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;

方案2：@Bean+@ConfigurationProperties

我们还可以把@ConfigurationProperties还可以直接定义在@bean的注解上，这是bean实体类就不用@Component和@ConfigurationProperties了，这边是Boot的动态数据源切换的类。

 package com.topcheer.oss.base.datasource;
 ​
 import com.alibaba.druid.pool.DruidDataSource;
 ​
 import com.xiaoleilu.hutool.crypto.symmetric.SymmetricAlgorithm;
 import com.xiaoleilu.hutool.crypto.symmetric.SymmetricCrypto;
 import com.xiaoleilu.hutool.util.CharsetUtil;
 import com.xiaoleilu.hutool.util.HexUtil;
 ​
 import lombok.extern.slf4j.Slf4j;
 ​
 @Slf4j
 public class UmspscDataSource extends DruidDataSource {
 ​
     private static final long serialVersionUID = 4766401181052251539L;
 ​
     private String passwordDis;

     /**
      * 密匙
      */
     private final static String Pkey ="1234565437892132";

     @Override
     public String getPassword() {
         if(passwordDis != null && passwordDis.length() > 0) {
             return passwordDis;
         }
         String encPassword = super.getPassword();
         if(null == encPassword) {
             return null;
         }
         log.info("数据库密码加解密，{" + encPassword + "}");
         try {
             //  密文解密，解密方法可以修改
             String key = HexUtil.encodeHexStr(Pkey);
             SymmetricCrypto aes = new SymmetricCrypto(SymmetricAlgorithm.AES, key.getBytes());
             passwordDis = aes.decryptStr(encPassword, CharsetUtil.CHARSET_UTF_8);
             return passwordDis;
         } catch (Exception e) {
             log.error("数据库密码解密出错，{"+encPassword + "}");
             //log.error(LogUtil.e(e));
             //throw new Exception("数据库密码解密失败！", e);
             return null;
         }
     }
 ​
 }

 @Bean(name = "systemDataSource")
     @ConfigurationProperties(ignoreUnknownFields = false, prefix = "spring.datasource.system")
     public DataSource systemDataSource() {
         return new UmspscDataSource();
     }
 ​
     @Bean(name = "secondDataSource")
     @ConfigurationProperties(ignoreUnknownFields = false, prefix = "spring.datasource.second")
     public DataSource secondDataSource() {
         return new UmspscDataSource();
     }

     @Bean(name="systemJdbcTemplate")
     public JdbcTemplate systemJdbcTemplate(
             @Qualifier("systemDataSource") DataSource dataSource) {
         return new JdbcTemplate(dataSource);
     }

     @Bean(name="secondJdbcTemplate")
     public JdbcTemplate secondJdbcTemplate(
             @Qualifier("secondDataSource") DataSource dataSource) {
         return new JdbcTemplate(dataSource);
     }

​

方案3:@ConfigurationProperties + @EnableConfigurationProperties

我们和上面例子一样注解属性，然后用 Spring的@Autowire来注入 mail configuration bean:

 package com.dxz.property;
 ​
 import org.springframework.boot.context.properties.ConfigurationProperties;
 ​
 @ConfigurationProperties(locations = "classpath:mail.properties", ignoreUnknownFields = false, prefix = "mail")
 public class MailProperties {
     private String host;
     private int port;
     private String from;
     private String username;
     private String password;
     private Smtp smtp;
 ​
     // ... getters and setters
     public String getHost() {
         return host;
     }
 ​
     public void setHost(String host) {
         this.host = host;
     }
 ​
     public int getPort() {
         return port;
     }
 ​
     public void setPort(int port) {
         this.port = port;
     }
 ​
     public String getFrom() {
         return from;
     }
 ​
     public void setFrom(String from) {
         this.from = from;
     }
 ​
     public String getUsername() {
         return username;
     }
 ​
     public void setUsername(String username) {
         this.username = username;
     }
 ​
     public String getPassword() {
         return password;
     }
 ​
     public void setPassword(String password) {
         this.password = password;
     }
 ​
     public Smtp getSmtp() {
         return smtp;
     }
 ​
     public void setSmtp(Smtp smtp) {
         this.smtp = smtp;
     }

     @Override
     public String toString() {
         return "MailProperties [host=" + host + ", port=" + port + ", from=" + from + ", username=" + username
                 + ", password=" + password + ", smtp=" + smtp + "]";
     }
 ​
     public static class Smtp {
         private boolean auth;
         private boolean starttlsEnable;
 ​
         public boolean isAuth() {
             return auth;
         }
 ​
         public void setAuth(boolean auth) {
             this.auth = auth;
         }
 ​
         public boolean isStarttlsEnable() {
             return starttlsEnable;
         }
 ​
         public void setStarttlsEnable(boolean starttlsEnable) {
             this.starttlsEnable = starttlsEnable;
         }
 ​
     }
 }

启动类及测试类：

 package com.dxz.property;
 ​
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.builder.SpringApplicationBuilder;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.RequestMethod;
 import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.bind.annotation.RestController;
 ​
 @RestController
 @SpringBootApplication
 @EnableConfigurationProperties(MailProperties.class)
 public class TestProperty1 {
 ​
     @Autowired
     private MailProperties mailProperties;

     @RequestMapping(value = "/hello", method = RequestMethod.GET)
     @ResponseBody
     public String hello() {
         System.out.println("mailProperties" + mailProperties);
         return "hello world";
     }
 ​
     public static void main(String[] args) {
         //SpringApplication.run(TestProperty1.class, args);
         new SpringApplicationBuilder(TestProperty1.class).web(true).run(args);
 ​
     }
 }

结果：

请注意@EnableConfigurationProperties注解。该注解是用来开启对@ConfigurationProperties注解配置Bean的支持。也就是@EnableConfigurationProperties注解告诉Spring Boot 能支持@ConfigurationProperties。如果不指定会看到如下异常:

Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.dxz.property.MailProperties] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

注意: 还有其他办法 (Spring Boot 总是有其他办法!) 让@ConfigurationProperties beans 被添加 – 用@Configuration或者 @Component注解, 这样就可以在 component scan时候被发现了。

	@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；