需求

在使用Spring/SpringBoot的过程中，我们总会使用到各种自定义配置，不可能把所有的配置都写到application.yml中，此时我们可以将某一部分自定义配置单独用一个文件提取出来，Spring也提供了相应的解决方案。

例子

• test.yml

huaiku:
  email: test@163.com
  address: 中华人民共和国

• 使用

public class YmlConfigTestBean {
    private String email;
    private String address;
    
    public YmlConfigTestBean(String email,String address) {
        this.address = address;
        this.email = email;
    }
    
    public void print() {
        System.out.println(String.format("Email:%s,Address:%s", this.email,this.address));
    }
}

• 配置

@Configuration
public class ApplicationConfigurations {
    
    @Bean public PropertyPlaceholderConfigurer yamlPropertyPlaceholderBean() {
        // 解析 yaml
        YamlPropertiesFactoryBean yamlProperty = new YamlPropertiesFactoryBean();
        yamlProperty.setResources(new ClassPathResource("test.yml"));
        // 配置 PropertyPlaceholder
        PropertyPlaceholderConfigurer yamlPropertyPlaceholder = new PropertyPlaceholderConfigurer();
        yamlPropertyPlaceholder.setProperties(yamlProperty.getObject());
        yamlPropertyPlaceholder.setFileEncoding("UTF-8");
        
        return yamlPropertyPlaceholder;
    }
    
    @Bean public YmlConfigTestBean ymlConfigTestBean(@Value("${huaiku.email}")String email,@Value("${huaiku.address}")String address) {
        return new YmlConfigTestBean(email,address);
    }
}

• 测试

@SpringBootApplication
public class SampleApplication {
    private static final Logger logger = LoggerFactory.getLogger(SampleApplication.class);
    public static void main(String[] args) {
        SpringApplication.run(SampleApplication.class, args);
    }

    @Bean public CommandLineRunner test(final YmlConfigTestBean bean) {
        return (args)-> {
            logger.info("打印....");
            bean.print();
        };
    }
}

• 结果

2018-12-06 17:06:32,312 INFO :-- [main .. ] o.s.SampleApplication 打印.... 
Email:test@163.com,Address:中华人民共和国

• 结语

此处提供的是基于Java注解的配置，在XML配置中把@Bean 注册的类改成XML注册的类便可。

• 补充

在项目中使用yml配置需要添加相关依赖yaml和yml依赖有所不同

1. yml

<dependency>
      <groupId>com.fasterxml.jackson.dataformat</groupId>
      <artifactId>jackson-dataformat-yaml</artifactId>
</dependency>

1. yaml

<dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
</dependency>