关于yaml是个什么东西，就不细说了。
yaml官方文档：http://www.yaml.org/
snakeyaml是用Java实现的解析yaml文件的库，官方wiki: https://bitbucket.org/asomov/snakeyaml/wiki/Documentation

下面上我解析yaml文件的例子：

// me.yaml
age: 1  
name: jiaobuchong
params:   
  event: what's up
  url:  http://www.jiaobuchong.com
favoriteBooks:      
  - Gone with the wind
  - The Little Prince

对应的JavaBean类：

// Me.java
public class Me {
    private Integer age;
    private String name;
    private Map<String, Object> params;
    private List<String> favoriteBooks;

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Map<String, Object> getParams() {
        return params;
    }

    public void setParams(Map<String, Object> params) {
        this.params = params;
    }

    public List<String> getFavoriteBooks() {
        return favoriteBooks;
    }

    public void setFavoriteBooks(List<String> favoriteBooks) {
        this.favoriteBooks = favoriteBooks;
    }

    @Override
    public String toString() {
        return "Me{" +
                "age=" + age +
                ", name='" + name + '\'' +
                ", params=" + params +
                ", favoriteBooks=" + favoriteBooks +
                '}';
    }
}

将配置项隐射到JavaBean中：

public class TestMeYaml {
    @Test
    public void testParseMeYaml() throws FileNotFoundException {
        Yaml yaml = new Yaml();
        Me me = yaml.loadAs(new FileInputStream(new File("config/me.yaml")), Me.class);
        System.out.println(me);
    }
}

如果yaml文件中有一个参数没有配置，隐射到JavaBean中的值就是null。