Json转HashMap及ArrayList＜HashMap＜＞＞时整型数据会被替换成浮点型解决方案

最新推荐文章于 2024-04-17 14:09:58 发布

原创最新推荐文章于 2024-04-17 14:09:58 发布 · 462 阅读

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文章标签：

#json #java #android

这是一个使用Gson库编写的Java工具类，主要功能是帮助将Java对象转换为JSON字符串，以及将JSON数据转换回对象列表和映射。它包括从JSON到ArrayList<HashMap<String,T>>的转换方法，并处理了整数转换为浮点数的问题。

写了个工具类分享一下：

package com.mmzou.shareapp;

import android.text.TextUtils;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.reflect.TypeToken;

import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * GsonUtils.
 */
public class GsonUtils {

    private static final Gson GSON = new Gson();

    public static Gson getGson() {
        return GSON;
    }

    /**
     * Object->json.
     *
     * @param obj Object
     * @return String
     */
    public static String toJson(Object obj) {
        return GSON.toJson(obj);
    }

    public static <T> T fromJson(String json, Class<T> cls) {
        return GSON.fromJson(json, cls);
    }

    /**
     * Json->ArrayList.
     */
    public static <T> ArrayList<T> jsonToList(String json, Class<T> clz) {
        Type type = new TypeToken<List<T>>() {}.getType();
        return GSON.fromJson(json, type);
    }


    /**
     * Json->ArrayList->HashMap.
     */
    public static <T> ArrayList<HashMap<String, T>> toListMap(String json, Class<T> clz) {
        Type type = new TypeToken<ArrayList<HashMap<String, T>>>() {}.getType();
        return GSON.fromJson(json, type);
    }

    /**
     * To solve the problem of converting json data to ArrayList Map, 
     * integer types will be replaced with floating point types.
     * 
     * @param jsonData String
     * @return ArrayList
     */
    public static ArrayList<HashMap<String, Object>> toListMapNoChange(String jsonData) {
        Gson gson = new GsonBuilder().registerTypeAdapter(new TypeToken<ArrayList<HashMap<String, Object>>>() {
        }.getType(), (JsonDeserializer<ArrayList<HashMap<String, Object>>>) (json, typeOfT, context) -> {
            ArrayList<HashMap<String, Object>> list = new ArrayList<>();
            JsonArray asJsonArray = json.getAsJsonArray();
            for (JsonElement jsonElement : asJsonArray) {
                HashMap<String, Object> hashMap = new HashMap<>();
                JsonObject asJsonObject = jsonElement.getAsJsonObject();
                Set<Map.Entry<String, JsonElement>> entrySet = asJsonObject.entrySet();
                for (Map.Entry<String, JsonElement> entry : entrySet) {
                    hashMap.put(entry.getKey(), entry.getValue());
                }
                list.add(hashMap);
            }

            return list;
        }).create();

        return TextUtils.isEmpty(jsonData) ? new ArrayList<>() : gson.fromJson(jsonData,
                new TypeToken<ArrayList<HashMap<String, Object>>>() {
                }.getType());
    }


    /**
     * To solve the problem of converting json data to Map, 
     * integer types will be replaced with floating point types.
     *
     * @param strJson String
     * @return HashMap
     */
    public static HashMap<String, Object> toMapNoChange(String strJson) {
        Gson gson = new GsonBuilder().registerTypeAdapter(new TypeToken<HashMap<String, Object>>() {
        }.getType(), (JsonDeserializer<HashMap<String, Object>>) (json, typeOfT, context) -> {
            HashMap<String, Object> hashMap = new HashMap<>();
            JsonObject jsonObject = json.getAsJsonObject();
            Set<Map.Entry<String, JsonElement>> entrySet = jsonObject.entrySet();
            for (Map.Entry<String, JsonElement> entry : entrySet) {
                hashMap.put(entry.getKey(), entry.getValue());
            }
            return hashMap;
        }).create();

        return TextUtils.isEmpty(strJson) ? new HashMap<>() : gson.fromJson(strJson,
                new TypeToken<HashMap<String, Object>>() {
                }.getType());
    }

}