使用Jackson将带有下划线的JSON反序列化为Java中的驼峰案例？

Question

要将具有camel case属性的java对象序列化为带有下划线的json,我们使用PropertyNamingStrategyas SNAKE_CASE.

那么,是否还有相反的事情要做.也就是说,使用下划线将json反序列化为带有camel case的Java对象.

例如,JSON:

{
    "user_id": "213sdadl"
    "channel_id": "asd213l"
}

应该反序列化到这个Java对象:

public class User {
    String userId; // should have value "213sdadl"
    String channelId; // should have value "asd213l"
}

我知道这样做的一种方法是通过@JsonProperty在现场级别工作的注释.我有兴趣知道任何全球设置.

Answer 1

那么你可以有一个PropertyNamingStrategy的实现,看起来像这样:

import org.codehaus.jackson.map.MapperConfig;
import org.codehaus.jackson.map.PropertyNamingStrategy;
import org.codehaus.jackson.map.introspect.AnnotatedField;
import org.codehaus.jackson.map.introspect.AnnotatedMethod;

public class CustomNameStrategy extends PropertyNamingStrategy {
    @Override
    public String nameForField(MapperConfig config, AnnotatedField field, String defaultName) {
        return convert(defaultName);
    }

    @Override
    public String nameForGetterMethod(MapperConfig config, AnnotatedMethod method, String defaultName) {
        return convert(defaultName);
    }

    @Override
    public String nameForSetterMethod(MapperConfig config, AnnotatedMethod method, String defaultName) {
        return convert(defaultName);
    }

    public String convert(String defaultName) {
        char[] arr = defaultName.toCharArray();
        StringBuilder nameToReturn = new StringBuilder();

        for (int i = 0; i < arr.length; i++) {
            if (arr[i] == '_') {
                nameToReturn.append(Character.toUpperCase(arr[i + 1]));
                i++;
            } else {
                nameToReturn.append(arr[i]);
            }
        }
        return nameToReturn.toString();
    }
}

然后在您的实现或执行desrialization的类中,您可以拥有:

ObjectMapper mapper = new ObjectMapper();
mapper.setPropertyNamingStrategy(new CustomNameStrategy());
YourClass yourClass = mapper.readValue(yourJsonString, YourClass.class);