package com.dsh.course.util;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.serializer.SerializerFeature;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.text.SimpleDateFormat;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

/**
 * 
 * 返回json数据封装工具类
 * 
 * @ClassName: JsonUtil
 * @author: yuds
 * @date: 2019-09-20 09:19:27
 * @version: V1.0.0
 */
public class JsonUtil {

	/**
	 * <li>将对象转化为json输出
	 * <li>QuoteFieldNames ———-输出key时是否使用双引号,默认为true
	 * <li>WriteMapNullValue ——–是否输出值为null的字段,默认为false
	 * <li>WriteNullNumberAsZero —-数值字段如果为null,输出为0,而非null
	 * <li>WriteNullListAsEmpty —–List字段如果为null,输出为[],而非null
	 * <li>WriteNullStringAsEmpty —字符类型字段如果为null,输出为”“,而非null
	 * <li>WriteNullBooleanAsFalse –Boolean字段如果为null,输出为false,而非null
	 * <li>DisableCircularReferenceDetect 禁止循环引用检测
	 */
	private static SerializerFeature[] serializerFeaturess = { SerializerFeature.WriteMapNullValue,
			SerializerFeature.WriteNullNumberAsZero, SerializerFeature.WriteNullListAsEmpty,
			SerializerFeature.WriteNullStringAsEmpty, SerializerFeature.WriteNullBooleanAsFalse,
			SerializerFeature.DisableCircularReferenceDetect, };

	private JsonUtil() {

	}

	/**
	 * fastJson Object转json
	 * 
	 * @param obj
	 * @return
	 */
	public static String objToJson(Object obj) {
		return JSON.toJSONString(obj, serializerFeaturess);
	}

	/**
	 * fastJson Object转json
	 * 
	 * @param obj
	 * @param dateFormat 时间格式化
	 * @return
	 */
	public static String objToJson(Object obj, String dateFormat) {
		return JSON.toJSONStringWithDateFormat(obj, dateFormat, serializerFeaturess);
	}

	// 定义jackson对象
	private static final ObjectMapper MAPPER = new ObjectMapper();

	/**
	 * 将对象转换成json字符串。
	 * <p>
	 * Title: pojoToJson
	 * </p>
	 * <p>
	 * Description:
	 * </p>
	 * 
	 * @param data
	 * @return
	 */
	public static String objectToJson(Object data) {
		try {
			SimpleDateFormat fmt = new SimpleDateFormat("yyyy-MM-dd HH:mm");
			MAPPER.setDateFormat(fmt);
			String string = MAPPER.writeValueAsString(data);
			return string;
		} catch (JsonProcessingException e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 将json结果集转化为对象
	 *
	 * @param jsonData json数据
	 * @param beanType    对象中的object类型
	 * @return
	 */
	public static <T> T jsonToPojo(String jsonData, Class<T> beanType) {
		try {
			T t = MAPPER.readValue(jsonData, beanType);
			return t;
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 将json数据转换成pojo对象list
	 * <p>
	 * Title: jsonToList
	 * </p>
	 * <p>
	 * Description:
	 * </p>
	 * 
	 * @param jsonData
	 * @param beanType
	 * @return
	 */
	public static <T> List<T> jsonToList(String jsonData, Class<T> beanType) {
		JavaType javaType = MAPPER.getTypeFactory().constructParametricType(List.class, beanType);
		try {
			List<T> list = MAPPER.readValue(jsonData, javaType);
			return list;
		} catch (Exception e) {
			e.printStackTrace();
		}

		return null;
	}

	public static JsonNode jsonToNode(String jsonData) {
		try {
			return MAPPER.readTree(jsonData);
		} catch (Exception ex) {
			ex.printStackTrace();
		}
		return null;
	}

	public static Map<String, String> jsonToMap(String json) {
		JsonNode nodes = jsonToNode(json);
		Iterator<Map.Entry<String, JsonNode>> fields = nodes.fields();
		Map<String, String> map = new HashMap<>();
		while (fields.hasNext()) {
			Map.Entry<String, JsonNode> next = fields.next();
			String value = next.getValue().asText("");
			map.put(next.getKey(), value);
		}
		return map;
	}

}