Jackson YAML 解析父对象和对象数组

Question

I have a yaml file with four parent objects. The fourth object is an array of element of which I will want to create a class for and populate. Is there a way to use the object mapper in jackson to ignore the first three objects and then parse my list of "InspectionModules"?

My yaml file looks like this:

# Don't care about these elements
InspectionGroups:
InspecitonModes:
ThresholdTypes:

# This array is of interest
InspectionModules:
 - feature : FC_Trig1
   name: "first inspection"
   Channels:
   - id: ICI_01
     category: Dia_MC_Config
 - feature : FC_Trig2
   name: "Diagonal Missing Cap"
   Channels:
   - id: ICI_02
     category: Dia_MC_Config

Basically I want to create a class called InspectionModule and have the mapper map the elements of the InspectionModules array into this class. Is there a simple way to do this in jackson? If not would it be recommended to reorganize our YAML file so we can leverage the object mapper?

Answer 1

I assume you already have some familiarity with Jackson's ObjectMapper .

First you will need a Java class representing the entire contents of your YAML file. Let's call it Root :

public class Root {

    @JsonProperty("InspectionModules")
    private List<InspectionModule> inspectionModules;

    // getters and setters omitted here for brevity
}

Notice that you'll need to use @JsonProperty to tell Jackson that the YAML name InspectionModules corresponds to your Java property inspectionModules in spite of their different spellings.

Next you need a Java class representing one of the YAML sections below the InspectionModules: .

public class InspectionModule {

    private String feature;

    private String name;

    @JsonProperty("Channels")
    private List<Channel> channels;

    // getters and setters omitted here for brevity
}

And finally you need a Channel class representing one of the YAML sections below Channels: You should be able to write this Java class by yourself already.

Now you are ready to use Jackson's YAMLMapper for reading your YAML file into a Root object.

File file = new File("example.yaml");
ObjectMapper objectMapper = new YAMLMapper();
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
Root root = objectMapper.readValue(file, Root.class);

Notice that you need to tell Jackson that it is OK to encounter unknown properties (like InspectionGroups ) during reading.