SpringBoot读取外部的配置文件的代码实现

customer:
  path: customer.yml

num: 5

import org.springframework.beans.factory.config.YamlPropertiesFactoryBean;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.env.EnvironmentPostProcessor;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.PropertiesPropertySource;
import org.springframework.core.env.PropertySource;
import org.springframework.core.io.FileSystemResource;
import org.springframework.core.io.Resource;

import java.io.File;
import java.util.Properties;

public class MyEnvironmentPostProcessor implements EnvironmentPostProcessor {

    @Override
    public void postProcessEnvironment(ConfigurableEnvironment environment, SpringApplication application) {
        //自定义配置文件，对应 application.yml 里的前缀
        String profiles = environment.getProperty("customer.path");
        //加载成PropertySource对象，并添加到Environment环境中
        File file = new File(profiles);
        Resource resource = new FileSystemResource(file);
        environment.getPropertySources().addLast(loadProfiles(resource));

    }

    /**
     * 加载单个配置文件
     * @param resource
     * @return
     */
    private PropertySource<?> loadProfiles(Resource resource) {
        // 判断资源是否存在
        if (!resource.exists()) {
            throw new IllegalArgumentException("资源" + resource + "不存在");
        }
        // 判断后缀名，兼容 .yml 文件和 .properties 文件
        if (resource.getFilename().contains(".yml")) {
            return loadYaml(resource);
        } else {
            return loadProperty(resource);
        }
    }

    /**
     * 加载properties格式的配置文件
     *
     * @param resource
     * @return
     */
    private PropertySource loadProperty(Resource resource) {
        try {
            //从输入流中加载一个Properties对象
            Properties properties = new Properties();
            properties.load(resource.getInputStream());
            return new PropertiesPropertySource(resource.getFilename(), properties);
        } catch (Exception ex) {
            throw new IllegalStateException("加载配置文件失败" + resource, ex);
        }
    }

    /**
     * 加载yml格式的配置文件
     *
     * @param resource
     * @return
     */
    private PropertySource loadYaml(Resource resource) {
        try {
            YamlPropertiesFactoryBean factory = new YamlPropertiesFactoryBean();
            factory.setResources(resource);
            //从输入流中加载一个Properties对象
            Properties properties = factory.getObject();
            return new PropertiesPropertySource(resource.getFilename(), properties);
        } catch (Exception ex) {
            throw new IllegalStateException("加载配置文件失败" + resource, ex);
        }
    }
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.env.Environment;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TestController {
    @Autowired
    private Environment environment;

    @GetMapping("/test")
    public void test() {
        // 读取 num 配置值，不为空则输出
        String num = environment.getProperty("num");
        if (num != null && !num.equals("")) {
            System.out.println("num = " + num);
        } else {
            System.out.println("num is null or ''");
        }
    }
}