package com.feeyo.util;

import java.util.Arrays;
import java.util.List;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import com.alibaba.fastjson.serializer.JSONSerializer;
import com.alibaba.fastjson.serializer.PropertyFilter;
import com.alibaba.fastjson.serializer.SerializeWriter;
import com.alibaba.fastjson.serializer.SerializerFeature;

/**
 * 字节处理相关工具类
 * 
 * @author jianghang
 */

@SuppressWarnings("unchecked")
public class JsonUtils {
	
	// 输出空置字段 
	private static final SerializerFeature[] features = { 
		SerializerFeature.WriteMapNullValue, 		
        SerializerFeature.WriteNullListAsEmpty, 
        SerializerFeature.WriteNullNumberAsZero,	
        SerializerFeature.WriteNullBooleanAsFalse, 
        SerializerFeature.WriteNullStringAsEmpty,        
        SerializerFeature.DisableCircularReferenceDetect
    }; 

	public static <T> T unmarshalFromByte(byte[] bytes, Class<T> targetClass) {
        return (T) JSON.parseObject(bytes, targetClass);// 默认为UTF-8
    }

    public static <T> T unmarshalFromByte(byte[] bytes, TypeReference<T> type) {
        return (T) JSON.parseObject(bytes, type.getType());
    }

    public static byte[] marshalToByte(Object obj) {
        return JSON.toJSONBytes(obj); // 默认为UTF-8
    }

    public static byte[] marshalToByte(Object obj, SerializerFeature... features) {
        return JSON.toJSONBytes(obj, features); // 默认为UTF-8
    }

    public static <T> T unmarshalFromString(String json, Class<T> targetClass) {
        return (T) JSON.parseObject(json, targetClass);// 默认为UTF-8
    }

    public static <T> T unmarshalFromString(String json, TypeReference<T> type) {
        return (T) JSON.parseObject(json, type);// 默认为UTF-8
    }
    
    public static String marshalToString(Object obj) {
        return JSON.toJSONString(obj, features); // 默认为UTF-8
    }

    public static String marshalToString(Object obj, SerializerFeature... features) {
        return JSON.toJSONString(obj, features); // 默认为UTF-8
    }

    /**
     * 可以允许指定一些过滤字段进行生成json对象
     */
    public static String marshalToString(Object obj, String... fliterFields) {
        final List<String> propertyFliters = Arrays.asList(fliterFields);
        SerializeWriter out = new SerializeWriter();
        try {
            JSONSerializer serializer = new JSONSerializer(out);
            serializer.getPropertyFilters().add(new PropertyFilter() {

                public boolean apply(Object source, String name, Object value) {
                    return !propertyFliters.contains(name);
                }

            });
            serializer.write(obj);
            return out.toString();
        } finally {
            out.close();
        }
    }
}