Spring Boot 通过@PropertySource或者@PropertySources实现设置多配置文件

Spring Boot 官网使用的是application.properties文件来实现文件的配置。但是实际情况下一个配置文件是不够用的，比如项目集成redis，mq，以及数据库比如mysql的时候，多个配置文件有利于开发及维护的管理。Spring Boot是通过@PropertySource或者@PropertySources来实现多配置文件的。首先看下@PropertySource源码：

public @interface PropertySource {

	/**
	 * Indicate the name of this property source. If omitted, a name will
	 * be generated based on the description of the underlying resource.
	 * @see org.springframework.core.env.PropertySource#getName()
	 * @see org.springframework.core.io.Resource#getDescription()
	 */
	String name() default "";

	/**
	 * Indicate the resource location(s) of the properties file to be loaded.
	 * 
Both traditional and XML-based properties file formats are supported
	 * — for example, {@code "classpath:/com/myco/app.properties"}
	 * or {@code "file:/path/to/file.xml"}.
	 * 
Resource location wildcards (e.g. **/*.properties) are not permitted;
	 * each location must evaluate to exactly one {@code .properties} resource.
	 * 
${...} placeholders will be resolved against any/all property sources already
	 * registered with the {@code Environment}. See {@linkplain PropertySource above}
	 * for examples.
	 * 
Each location will be added to the enclosing {@code Environment} as its own
	 * property source, and in the order declared.
	 */
	String[] value();

	/**
	 * Indicate if failure to find the a {@link #value() property resource} should be
	 * ignored.
	 * 
{@code true} is appropriate if the properties file is completely optional.
	 * Default is {@code false}.
	 * @since 4.0
	 */
	boolean ignoreResourceNotFound() default false;

	/**
	 * A specific character encoding for the given resources, e.g. "UTF-8".
	 * @since 4.3
	 */
	String encoding() default "";

	/**
	 * Specify a custom {@link PropertySourceFactory}, if any.
	 * 
By default, a default factory for standard resource files will be used.
	 * @since 4.3
	 * @see org.springframework.core.io.support.DefaultPropertySourceFactory
	 * @see org.springframework.core.io.support.ResourcePropertySource
	 */
	Class factory() default PropertySourceFactory.class;

}

name

为这里资源指定一个名称，这个没什么好说的。

value

用于指定资源路径，注意通配符（比如/*.properties）在这里是没有用的，路径必须明确指向到一个properties文件。因为这里value的类型是String数组，因此这里可以指定多个配置文件。

ignoreResourceNotFound

是否忽略找不到指定路径的情况。

encoding

指定编码类型，默认为空。

 

通过@PropertySource源码解析我们就能够知道应该如何使用该注解。这里假设需要多配置两个配置文件：redis.properties和database.properties:

只需要在启动类上加上@PropertySource即可：

@SpringBootApplication
@ComponentScan(basePackages = {"com.aron"})//通过扫描本路径可不需将ctl包和启动类放在同一目录下
@PropertySource(value= {"classpath:redis.properties","classpath:database.properties"}
				, name="ss"
				, encoding="utf-8"
				,ignoreResourceNotFound=true)
public class ProjectMainEntranceApplication {

	public static void main(String[] args) {
		SpringApplication.run(ProjectMainEntranceApplication.class, args);
	}
}

而对于@PropertySources 来说，参照其源码：

public @interface PropertySources {

	PropertySource[] value();

}

我们可以看到其实就是PropertySource的数组，因此通过@PropertySources 配置方式为：

@SpringBootApplication
@ComponentScan(basePackages = { "com.aron" }) // 通过扫描本路径可不需将ctl包和启动类放在同一目录下
@PropertySources({ @PropertySource("classpath:redis.properties"), 
				   @PropertySource("classpath:database.properties") })
public class ProjectMainEntranceApplication {

	public static void main(String[] args) {
		SpringApplication.run(ProjectMainEntranceApplication.class, args);
	}
}