package com.uas.demo.utils;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * JSON 工具类
 *
 * history：
 * Created by huxz on 2017-3-1 10:16:03
 */
public final class JacksonUtils {

	private static ObjectMapper objectMapper;

	/**
	 * 把JSON文本parse为JavaBean
	 */
	public static <T> T fromJson(String text, Class<T> clazz) {
		if (objectMapper == null) {
			objectMapper = new ObjectMapper();
		}
		try {
			return objectMapper.readValue(text, clazz);
		} catch (IOException e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 把JSON文本parse成JavaBean集合
	 */
	public static <T> List<T> fromJsonArray(String text, Class<T> clazz) {
		if (objectMapper == null) {
			objectMapper = new ObjectMapper();
		}
		JavaType javaType = objectMapper.getTypeFactory().constructParametricType(ArrayList.class, clazz);
		try {
			return objectMapper.readValue(text, javaType);
		} catch (IOException e) {
			e.printStackTrace();
		}
		return Collections.emptyList();
	}

	/**
	 * 将JavaBean序列化为JSON文本
	 */
	public static String toJson(Object object) {
		if (objectMapper == null) {
			objectMapper = new ObjectMapper();
		}
		try {
			return objectMapper.writeValueAsString(object);
		} catch (JsonProcessingException e) {
			e.printStackTrace();
		}
		return null;
	}

}