JacksonMapper来反序列化空值

Question

我要将Json空值反序列化为Java对象空字符串

我能够创建我的自定义反序列化器，但是当Json值为null时，它不会进入反序列化器。

我该如何反序列化它?

提前感谢!

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
我通过

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

Answer 1

也许覆盖getNullValue()方法就足够了?

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 "";
}
}