JacksonMapper反序列化null值

Question

我要将Json null值反序列化为Java Object空字符串

我可以创建自定义反序列化器，但是当Json值为null时，它不会进入反序列化器。

我该如何反序列化呢？

提前致谢！

public class CustomStringDeserializer extends JsonDeserializer<String> {
@Override
public String deserialize(JsonParser jsonparser, DeserializationContext deserializationcontext) throws IOException,
        JsonProcessingException {

    String str = jsonparser.getText();

    try {
        return (str == null) ? "" : str;
    } catch (Exception e) {
        throw new RuntimeException(e);
    }

}

}

   public CustomObjectMapper() {
        SimpleModule _module = new SimpleModule("Module", new Version(1, 9, 10, "FINAL"));
        _module.addDeserializer(String.class, new CustomStringDeserializer());
}

谢谢@nutlike 我这样做是

    @Override
public String getNullValue() {
    return "";
}

Answer 1

覆盖方法getNullValue()也许就足够了？

public class CustomStringDeserializer extends JsonDeserializer<String> {

@Override
public String deserialize(JsonParser jsonparser,
        DeserializationContext deserializationcontext) throws IOException,
        JsonProcessingException {

    return jsonparser.getText();

}

@Override
public String getNullValue() {
    return "";
}

}