settings.yml 部分内容：

period:
  from: 2022-05-10
  to: 2023-01-01

如果我设置变量：

    private static String periodFrom;
    private static String periodTo;
    
    Yaml yaml = new Yaml();
    FileInputStream fileInputStream = new FileInputStream("settings.yml");
    HashMap yamlMap = yaml.load(fileInputStream);
    
    HashMap period = (HashMap) yamlMap.get("period");
    periodFrom = (String) period.get("from");
    periodTo = (String) period.get("to");
	System.out.println(periodFrom);

报错：Exception in thread "main" java.lang.ClassCastException: java.util.Date cannot be cast to java.lang.String

也就是这里变量 periodFrom 和 periodTo 必须是 Date 或者 Object 这类范围更广的类型。java 为何会认定我设置的参数本身不是 String 而是 Date 呢？

如果我将 String 类型改成 Object 的话，sout 输出的是：Tue May 10 08:00:00 CST 2022 而不是我希望的 2022-05-10，这又是为什么呢？网上查了好像没什么头绪，还请赐教...

我希望的是读取这个日期参数，然后进行检查是否格式正确，如果正确，那么该日期将转换后（转换成 2017-01-01T00:00:00Z ）用于从 gitlab 拉取 commit 信息

参考： https://github.com/gitlab4j/gitlab4j-api#commitsapi

// Get a list of commits associated with the specified branch that fall within the specified time window
// This uses the ISO8601 date utilities the in org.gitlab4j.api.utils.ISO8601 class
Date since = ISO8601.toDate("2017-01-01T00:00:00Z");
Date until = new Date(); // now
List<Commit> commits = gitLabApi.getCommitsApi().getCommits(1234, "new-feature", since, until);

xml 需要添加坐标：

    <repositories>
        <repository>
            <id>apache</id>
            <url>https://repo.maven.apache.org/maven2</url>
        </repository>
    </repositories>
    
    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.yaml/snakeyaml -->
        <dependency>
            <groupId>org.yaml</groupId>
            <artifactId>snakeyaml</artifactId>
            <version>1.33</version>
        </dependency>
    </dependencies>