• SpringBoot注入配置文件的3种方法

    方案1:@ConfigurationProperties+@Component

     1 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
 2 
 3 /**
 4  * 将配置文件中配置的每一个属性的值，映射到这个组件中
 5  * @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；
 6  *      prefix = "person"：配置文件中哪个下面的所有属性进行一一映射
 7  *
 8  * 只有这个组件是容器中的组件，才能容器提供的@ConfigurationProperties功能；
 9  *
10  */
11 @Component
12 @ConfigurationProperties(prefix = "person")
13 public class Person {
14 ​
15     private String lastName;
16     private Integer age;
17     private Boolean boss;
18     private Date birth;
19 ​
20     private Map<String,Object> maps;
21     private List<Object> lists;
22     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。

     1 package com.topcheer.oss.base.datasource;
 2 ​
 3 import com.alibaba.druid.pool.DruidDataSource;
 4 ​
 5 import com.xiaoleilu.hutool.crypto.symmetric.SymmetricAlgorithm;
 6 import com.xiaoleilu.hutool.crypto.symmetric.SymmetricCrypto;
 7 import com.xiaoleilu.hutool.util.CharsetUtil;
 8 import com.xiaoleilu.hutool.util.HexUtil;
 9 ​
10 import lombok.extern.slf4j.Slf4j;
11 ​
12 @Slf4j
13 public class UmspscDataSource extends DruidDataSource {
14 ​
15     private static final long serialVersionUID = 4766401181052251539L;
16 ​
17     private String passwordDis;
18     
19     /**
20      * 密匙
21      */
22     private final static String Pkey ="1234565437892132";
23     
24     @Override
25     public String getPassword() {
26         if(passwordDis != null && passwordDis.length() > 0) {
27             return passwordDis;
28         }
29         String encPassword = super.getPassword();
30         if(null == encPassword) {
31             return null;
32         }
33         log.info("数据库密码加解密，{" + encPassword + "}");
34         try {
35             //  密文解密，解密方法可以修改
36             String key = HexUtil.encodeHexStr(Pkey);
37             SymmetricCrypto aes = new SymmetricCrypto(SymmetricAlgorithm.AES, key.getBytes());
38             passwordDis = aes.decryptStr(encPassword, CharsetUtil.CHARSET_UTF_8);
39             return passwordDis;
40         } catch (Exception e) {
41             log.error("数据库密码解密出错，{"+encPassword + "}");
42             //log.error(LogUtil.e(e));
43             //throw new Exception("数据库密码解密失败！", e);
44             return null;
45         }
46     }
47 ​
48 }
     1 @Bean(name = "systemDataSource")
 2     @ConfigurationProperties(ignoreUnknownFields = false, prefix = "spring.datasource.system")
 3     public DataSource systemDataSource() {
 4         return new UmspscDataSource();
 5     }
 6 ​
 7     @Bean(name = "secondDataSource")
 8     @ConfigurationProperties(ignoreUnknownFields = false, prefix = "spring.datasource.second")
 9     public DataSource secondDataSource() {
10         return new UmspscDataSource();
11     }
12     
13     @Bean(name="systemJdbcTemplate")
14     public JdbcTemplate systemJdbcTemplate(
15             @Qualifier("systemDataSource") DataSource dataSource) {
16         return new JdbcTemplate(dataSource);
17     }
18     
19     @Bean(name="secondJdbcTemplate")
20     public JdbcTemplate secondJdbcTemplate(
21             @Qualifier("secondDataSource") DataSource dataSource) {
22         return new JdbcTemplate(dataSource);
23     }

    ​

     

    

    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:
    

    

     1 package com.dxz.property;
 2 ​
 3 import org.springframework.boot.context.properties.ConfigurationProperties;
 4 ​
 5 @ConfigurationProperties(locations = "classpath:mail.properties", ignoreUnknownFields = false, prefix = "mail")
 6 public class MailProperties {
 7     private String host;
 8     private int port;
 9     private String from;
10     private String username;
11     private String password;
12     private Smtp smtp;
13 ​
14     // ... getters and setters
15     public String getHost() {
16         return host;
17     }
18 ​
19     public void setHost(String host) {
20         this.host = host;
21     }
22 ​
23     public int getPort() {
24         return port;
25     }
26 ​
27     public void setPort(int port) {
28         this.port = port;
29     }
30 ​
31     public String getFrom() {
32         return from;
33     }
34 ​
35     public void setFrom(String from) {
36         this.from = from;
37     }
38 ​
39     public String getUsername() {
40         return username;
41     }
42 ​
43     public void setUsername(String username) {
44         this.username = username;
45     }
46 ​
47     public String getPassword() {
48         return password;
49     }
50 ​
51     public void setPassword(String password) {
52         this.password = password;
53     }
54 ​
55     public Smtp getSmtp() {
56         return smtp;
57     }
58 ​
59     public void setSmtp(Smtp smtp) {
60         this.smtp = smtp;
61     }
62     
63     @Override
64     public String toString() {
65         return "MailProperties [host=" + host + ", port=" + port + ", from=" + from + ", username=" + username
66                 + ", password=" + password + ", smtp=" + smtp + "]";
67     }
68 ​
69     public static class Smtp {
70         private boolean auth;
71         private boolean starttlsEnable;
72 ​
73         public boolean isAuth() {
74             return auth;
75         }
76 ​
77         public void setAuth(boolean auth) {
78             this.auth = auth;
79         }
80 ​
81         public boolean isStarttlsEnable() {
82             return starttlsEnable;
83         }
84 ​
85         public void setStarttlsEnable(boolean starttlsEnable) {
86             this.starttlsEnable = starttlsEnable;
87         }
88 ​
89     }
90 }
    

    


    启动类及测试类：
    

    

     1 package com.dxz.property;
 2 ​
 3 import org.springframework.beans.factory.annotation.Autowired;
 4 import org.springframework.boot.autoconfigure.SpringBootApplication;
 5 import org.springframework.boot.builder.SpringApplicationBuilder;
 6 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 7 import org.springframework.web.bind.annotation.RequestMapping;
 8 import org.springframework.web.bind.annotation.RequestMethod;
 9 import org.springframework.web.bind.annotation.ResponseBody;
10 import org.springframework.web.bind.annotation.RestController;
11 ​
12 @RestController
13 @SpringBootApplication
14 @EnableConfigurationProperties(MailProperties.class)
15 public class TestProperty1 {
16 ​
17     @Autowired
18     private MailProperties mailProperties;
19     
20     @RequestMapping(value = "/hello", method = RequestMethod.GET)
21     @ResponseBody
22     public String hello() {
23         System.out.println("mailProperties" + mailProperties);
24         return "hello world";
25     }
26 ​
27     public static void main(String[] args) {
28         //SpringApplication.run(TestProperty1.class, args);
29         new SpringApplicationBuilder(TestProperty1.class).web(true).run(args);
30 ​
31     }
32 }
    

    


    结果：
    

    img
    

    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；
    

    
    
          
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            原文地址：https://www.cnblogs.com/dalianpai/p/11670836.html
          
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