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package com.github.bootfastconfig.jackson;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.github.bootfastconfig.springtool.ObjectUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.text.DateFormat;
import java.text.SimpleDateFormat;

public class JsonBinder {


    private static Logger logger = LoggerFactory.getLogger(JsonBinder.class);

    private ObjectMapper mapper;

    public JsonBinder(JsonInclude.Include inclusion) {
        mapper = new ObjectMapper();

        // 设置输出包含的属性
        mapper.setSerializationInclusion(inclusion);
        // 设置输入时忽略JSON字符串中存在而Java对象实际没有的属性
        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        mapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);

        mapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
    }

    /**
     * 创建输出全部属性到Json字符串的Binder.
     */
    public static JsonBinder buildNormalBinder() {
        return new JsonBinder(JsonInclude.Include.ALWAYS);
    }

    /**
     * 创建只输出非空属性到Json字符串的Binder.
     */
    public static JsonBinder buildNonNullBinder() {
        return new JsonBinder(JsonInclude.Include.NON_NULL);
    }

    /**
     * 创建只输出初始值被改变的属性到Json字符串的Binder.
     */
    public static JsonBinder buildNonDefaultBinder() {
        return new JsonBinder(JsonInclude.Include.NON_DEFAULT);
    }

    /**
     * 如果JSON字符串为Null或"null"字符串,返回Null. 如果JSON字符串为"[]",返回空集合.
     * 
     * 如需读取集合如List/Map,且不是List这种简单类型时使用如下语句: List beanList =
     * binder.getMapper().readValue(listString, new TypeReference>()
     * {});
     */
    public  T fromJson(String jsonString, Class clazz) {
        if (ObjectUtil.isNotEmpty(jsonString)) {
            return null;
        }
        try {
            return mapper.readValue(jsonString, clazz);
        } catch (IOException e) {
            logger.warn("parse json string error:" + jsonString, e);
            return null;
        }
    }

    /**
     * 如果对象为Null,返回"null". 如果集合为空集合,返回"[]".
     */
    public String toJson(Object object) {
        try {
            return mapper.writeValueAsString(object);
        } catch (IOException e) {
            logger.warn("write to json string error:" + object, e);
            return null;
        }
    }

    /**
     * 设置转换日期类型的format pattern,如果不设置默认打印Timestamp毫秒数.
     */
    public void setDateFormat(String pattern) {
        if (ObjectUtil.isNotEmpty(pattern)) {
            DateFormat df = new SimpleDateFormat(pattern);
            mapper.setDateFormat(df);
        }
    }

    /**
     * 當JSON裡只含有Bean的部分屬性時，更新一個已存在Bean，只覆蓋該部分的屬性.
     */
    @SuppressWarnings("unchecked")
    public  T update(String jsonString, T object) {
        try {
            return (T) mapper.readerForUpdating(object).readValue(jsonString);
        } catch (JsonProcessingException e) {
            logger.warn("update json string:" + jsonString + " to object:" + object + " error.", e);
        } catch (IOException e) {
            logger.warn("update json string:" + jsonString + " to object:" + object + " error.", e);
        }
        return null;
    }

    /**
     * 取出Mapper做进一步的设置或使用其他序列化API.
     */
    public ObjectMapper getMapper() {
        return mapper;
    }

}