在日常开发过程中，发布一些产品或者框架时，会遇到某些功能需要一些配置才能正常运行，这时我们需要的提供默认配置项，同时用户也能覆盖进行个性化

创建Initializer

public class FrameContextInitializer implements ApplicationContextInitializer  {

    @Override
    public void initialize(ConfigurableApplicationContext applicationContext) {
        System.out.println("FrameContextInitializer--Start");
        System.out.println("FrameContextInitializer--End");
    }
}

配置Initializer

resources/META-INF文件夹下创建spring.factories文件，指定实现类

org.springframework.context.ApplicationContextInitializer=com.haopan.frame.common.initializer.FrameContextInitializer

实现Initializer

读取默认yml文件

 String frameYAMLFilePath = ClassPathFileUtil.getFilePathActual("systemfile/config/frame.yml");
 
 public static String getFilePathActual(String classFilePath) {
        String filePath = "";
        try {
            String templateFilePath = "tempfiles/classpathfile/";
            File tempDir = new File(templateFilePath);
            if (!tempDir.exists()) {
                tempDir.mkdirs();
            }
            String[] filePathList = classFilePath.split("/");
            String checkFilePath = "tempfiles/classpathfile";
            for (String item : filePathList) {
                checkFilePath += "/" + item;
            }
            File tempFile = new File(checkFilePath);
            if (tempFile.exists()) {
               tempFile.delete();
            }
            //解析
            ClassPathResource classPathResource = new ClassPathResource(classFilePath);
            InputStream inputStream = classPathResource.getInputStream();
            checkFilePath = "tempfiles/classpathfile";
            for (int i = 0; i < filePathList.length; i++) {
                checkFilePath += "/" + filePathList[i];
                if (i == filePathList.length - 1) {
                    //文件
                    File file = new File(checkFilePath);
                    if(!file.exists()){
                        FileUtils.copyInputStreamToFile(inputStream, file);
                    }
                } else {
                    //目录
                    tempDir = new File(checkFilePath);
                    if (!tempDir.exists()) {
                        tempDir.mkdirs();
                    }
                }
            }
            inputStream.close();
            filePath = checkFilePath;

        } catch (Exception e) {
            e.printStackTrace();
        }
        return filePath;
    }

将yml内容加到环境上下文

这边的addLast是执行顺序为最后读取，如果项目的yml文件没有读取到，则默认配置是一个保底

System.out.println("FrameContextInitializer--Start");    

PropertySource<?> propertySource = loader.load("frameConfiguration", new InputStreamResource(new FileInputStream(frameYAMLFilePath))).get(0);
applicationContext.getEnvironment().getPropertySources().addLast(propertySource);

System.out.println("FrameContextInitializer--End");