如何在 YAML 文件中为简单的 POJO 定义映射?

How to define a map in a YAML file for simple POJO?

我正在使用 SnakeYAML 将某些 configuration/property 值解析为配置对象(定义如下)。

我的 YAML 文件如下所示:

# Thread
batchLimit: 1000
threadCountLimit: 2

# Some more config
key: value

# Map
keyMapping: <What goes here?>

我的配置 class 如下所示:

public class Configuration{
  int batchlimit;
  int threadCountLimit;
  ...
  Map<String,String> keyMapping;
}

如何在YAML文件中定义keyMapping使其可以被SnakeYAML直接解析?

这是它的样子:

#MAP
keyMapping: 
    key1: value1
    key2: value2

一般YAML格式都有键值对的天然支持。 查看以下教程(仅作为示例):https://github.com/Animosity/CraftIRC/wiki/Complete-idiot's-introduction-to-yaml

或 google "yaml map" 了解更多详情。

具有键值对的 Yaml 文件 "AppParams.yml":

someConfig:
    key1: value1
    key2: value2

POJO:

public class ApplicationParameters {
    private Map<String, String> someConfig;

    public ApplicationParameters() {
    }

    public Map<String, String> getSomeConfig() {
        return someConfig;
    }

    public void setSomeConfig(Map<String, String> someConfig) {
        this.someConfig = someConfig;
    }
}

Reader:

ObjectMapper mapper = new ObjectMapper(new YAMLFactory());
File paramFile = new File("AppParams.yml");
ApplicationParameters applicationParameters = mapper.readValue(paramFile, ApplicationParameters.class);

Map<String, String> someConfig = applicationParameters.getSomeConfig();

String key1Value = someConfig.get("key1");    //returns "value1"

上面的例子在POM.xml中使用了这些依赖:

 <dependencies>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>2.9.8</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.9.8</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.dataformat</groupId>
        <artifactId>jackson-dataformat-yaml</artifactId>
        <version>2.9.8</version>
    </dependency>
</dependencies>