Java序列化，解决字段为null与序列化后首字母变小写问题

fastjson.jar

package com.apt.utils;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.serializer.ValueFilter;
import com.apt.model.TBTEntity;

import org.json.JSONObject;

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

/**
 * Created by Administrator on 2017/4/14.
 */

public class JsonUtil {
    private final static  String tag="JsonUtil";
    /**
     * 反序列化一个实体
     * @param jsonString {"Address":"北京市通州区科创六街","BaiDuLat":39.814426895001,"BaiDuLng":116.55877636322,"CellId":41776,"Lac":4388,"Lat":39.808475,"Lng":116.552281,"MNC":"0"}
     * @param clazz CellInfo.class
     * @param <T>
     * @return
     */
    public static <T> Object parseObject(String jsonString,Class<T> clazz){
        try{
            if(jsonString==null||jsonString.equals("")){
                return null;
            }
            return JSON.parseObject(jsonString, clazz);
        }
        catch(Exception ex){
            LogUtil.WriteError(ex,tag+"->toBean()");
            return null;
        }
    }

    /**
     * 反序列化一个泛型集合
     * @param json
     * @return
     */
    public static <T>List<T> parseArray(String json,Class<T> clazz){
        List<T> list=new ArrayList<T>();
        try{
            list = JSON.parseArray(json, clazz);
        }
        catch(Exception ex){
            LogUtil.WriteError(ex,tag+"->parseArray()");
        }
        return list;
    }
    /**
     * 反序列化一个具体集合
     * @param json
     * @return
     */
    public static List<TBTEntity> getListTBTEntity(String json){
        List<TBTEntity> list=new ArrayList<TBTEntity>();
        try{
            list = JSON.parseArray(json, TBTEntity.class);
        }
        catch(Exception ex){
            LogUtil.WriteError(ex,tag+"->getListTBTEntity()");
        }
        return list;
    }

    public static String toJSONString(Object clazz){
        String json="";
        try{
            json = JSON.toJSONString(clazz,filter);
        }
        catch(Exception ex){
            LogUtil.WriteError(ex,tag+"->toJSONString()");
        }
        json=formatJson(json);
        return json;
    }

    //解决序列化对对象为null的字段不序列化的问题
    private static ValueFilter filter = new ValueFilter() {
        @Override
        public Object process(Object obj, String s, Object v) {
            if(v==null)
                return "";
            return v;
        }
    };

    //解决序列后首字母变成小写的问题
    private static String formatJson(String orgJson) {
        JSONObject jo = new JSONObject();
        try {
            JSONObject jsonObject = new JSONObject(orgJson);
            Iterator iterator = jsonObject.keys();

            while (iterator.hasNext()) {
                String key = (String) iterator.next();
                char chars[] = key.toCharArray();
                if (key.length() > 1 && Character.isLowerCase(key.charAt(0))) {
                    chars[0] = Character.toUpperCase(chars[0]);
                }

                Boolean bl = jsonObject.isNull(key);
                if (bl) {
                    jo.put(new String(chars), null);
                } else {
                    Object object = jsonObject.get(key);
                    try {
                        if (object instanceof Number) {
                            jo.put(new String(chars),
                                    ((Number) object).intValue());
                        } else {
                            jo.put(new String(chars), jsonObject.getString(key));
                        }
                    } catch (Exception e) {
                        jo.put(new String(chars), jsonObject.getString(key));
                    }
                }
            }
        } catch (Exception ex) {
            LogUtil.WriteError(ex,tag+"->formatJson()");
        }
        return jo.toString();
    }
}