Json多層級動態結構數據解析

一、工具

（1）GSON

Google Gson是一個簡單的基于Java的庫，用于將Java對象序列化為JSON，反之亦然。它是由Google開發的一個開源庫。

以下幾點說明為什么應該使用這個庫 -

標準化 - Gson是一個由Google管理的標準化庫。
高效 - 這是對Java標準庫的可靠，快速和高效的擴展。
優化 - Gson庫經過高度優化。
支持泛型 - 它為泛型提供了廣泛的支持。
支持復雜的內部類 - 它支持具有深度繼承層次結構的復雜對象。

（2）OGNL表達式

OGNL表達式是Object-Graph Navigation Language的縮寫，是一種功能強大的表達式語言，通過

簡單一致的表達式語法，可以存取對象的任意屬性，調用對象的方法，遍歷整個對象的結構圖，實現字段類型轉換。

二、mavan所需引入的依賴

<dependency> 
  <groupId>ognl</groupId> 
  <artifactId>ognl</artifactId> 
  <version>3.1.1</version> 
</dependency> 
<dependency> 
  <groupId>com.google.code.gson</groupId> 
  <artifactId>gson</artifactId> 
  <version>2.9.0</version>
</dependency>
<dependency>
  <groupId>junit</groupId>
  <artifactId>junit</artifactId>
  <version>4.13.2</version>
</dependency>

三、工具類

public class JsonUtils { 

/**
* 將指定JSON轉為Map對象，Key固定為String，對應JSONkey
* Value分情況：
* 1. Value是字符串，自動轉為字符串,例如:{"a","b"} 6 * 2. Value是其他JSON對象，自動轉為Map，例如：{"a":{"b":"2"}}}
* 3. Value是數組，自動轉為List<Map>，例如：{"a":[{"b":"2"},"c":"3"]}
* @param json 輸入的JSON對象
* @return 動態的Map集合
*/
public static Map<String,Object> transferToMap(String json) {
    Gson gson = new Gson();
    Map<String, Object> map = gson.fromJson(json,
    new TypeToken<Map<String, Object>>() {}.getType());
    return map;
}

/**
* 簡化方法
* @param json 原始的JSON數據
* @param path OGNL規則表達式
* @param clazz Value對應的目標類
* @return clazz對應數據
*/
public static <T> T getValue(String json, String path, Class<T> clazz) {
  try {
    Map map = transferToMap(json);
    OgnlContext context = new OgnlContext();
    context.setRoot(map);
    T value = (T) Ognl.getValue(path, context, context.getRoot());
     return value;
    } catch (Exception e) {
     throw new RuntimeException(e);
   }
}

public static <T> T getValueFromMap(Map map, String path, Class<T> clazz) {
  try {
   OgnlContext context = new OgnlContext();
    context.setRoot(map);
    T value = (T) Ognl.getValue(path, context, context.getRoot());
     return value;
    } catch (Exception e) {
     throw new RuntimeException(e);
   }
  }
 }

四、測試用例

import com.itlaoqi.JsonUtils;
import org.junit.Test;
import java.util.List;
import java.util.Map;
public class JsonCase {
/**
* {
* "a": {
* "b": {
* "c": {
* "d": {
* "e": "nothing"
* }
* }
* }
* }
* }
*/
/**
* 超多層級JSON嵌套的快速提取
*/
@Test
public void case0(){
String text = "{\n" +
" \"a\": {\n" +
" \"b\": {\n" +
" \"c\": {\n" +
" \"d\": {\n" +
" \"e\": \"nothing\"\n" +
" }\n" +
" }\n" +
" }\n" +
" }\n" +
"}";
Map<String, Object> jsonMap = JsonUtils.transferToMap(json);
String e = JsonUtils.getValue(text, "a.b.c.d.e", String.class);
System.out.println(e);
}

/**
* {
* "showapi_res_error": "",
* "showapi_res_id": "628cc9850de3769f06edbb49",
* "showapi_res_code": 0,
* "showapi_fee_num": 1,
* "showapi_res_body": {"ret_code":0,"area":"南安","areaid":"101230506","areaCode":"350583","hourList":
[{"weather_code":"07","time":"202205242000","area":"南安","wind_direction":"東南
風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"20"},
{"weather_code":"07","time":"202205242100","area":"南安","wind_direction":"東風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"20"},
{"weather_code":"07","time":"202205242200","area":"南安","wind_direction":"東風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"20"},
{"weather_code":"07","time":"202205242300","area":"南安","wind_direction":"東風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"20"},
{"weather_code":"07","time":"202205250000","area":"南安","wind_direction":"南風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"21"},
{"weather_code":"07","time":"202205250100","area":"南安","wind_direction":"西風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"21"},
{"weather_code":"07","time":"202205250200","area":"南安","wind_direction":"西北
風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"21"},
{"weather_code":"02","time":"202205250300","area":"南安","wind_direction":"西北
風","wind_power":"0-3級微風
<5.4m/s","weather":"陰","areaid":"101230506","temperature":"21"},
{"weather_code":"02","time":"202205250400","area":"南安","wind_direction":"西北
風","wind_power":"0-3級微風
<5.4m/s","weather":"陰","areaid":"101230506","temperature":"21"},
{"weather_code":"02","time":"202205250500","area":"南安","wind_direction":"西風","wind_power":"0-3級微風
<5.4m/s","weather":"陰","areaid":"101230506","temperature":"21"},
{"weather_code":"07","time":"202205250600","area":"南安","wind_direction":"西北
風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"21"},
{"weather_code":"07","time":"202205250700","area":"南安","wind_direction":"西北
風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"21"},
{"weather_code":"07","time":"202205250800","area":"南安","wind_direction":"西北
風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"21"},
{"weather_code":"07","time":"202205250900","area":"南安","wind_direction":"西南
風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"22"},
{"weather_code":"07","time":"202205251000","area":"南安","wind_direction":"南風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"23"},
{"weather_code":"07","time":"202205251100","area":"南安","wind_direction":"東風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"24"},
{"weather_code":"07","time":"202205251200","area":"南安","wind_direction":"東風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"24"},
{"weather_code":"07","time":"202205251300","area":"南安","wind_direction":"東風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"25"},
{"weather_code":"07","time":"202205251400","area":"南安","wind_direction":"東南
風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"25"},
{"weather_code":"07","time":"202205251500","area":"南安","wind_direction":"東南
風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"25"},
{"weather_code":"07","time":"202205251600","area":"南安","wind_direction":"東南
風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"24"},
{"weather_code":"07","time":"202205251700","area":"南安","wind_direction":"東南
風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"23"},
{"weather_code":"07","time":"202205251800","area":"南安","wind_direction":"東南
風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"23"},
{"weather_code":"07","time":"202205251900","area":"南安","wind_direction":"東南
風","wind_power":"0-3級微風 <5.4m/s","weather":"小雨","areaid":"101230506","temperature":"23"}]}
* }
*/
private String json = "{\n" +
"\"showapi_res_error\": \"\",\n" +
"\"showapi_res_id\": \"628cc9850de3769f06edbb49\",\n" +
"\"showapi_res_code\": 0,\n" +
"\"showapi_fee_num\": 1,\n" +
"\"showapi_res_body\": {\"ret_code\":0,\"area\":\"南安
\",\"areaid\":\"101230506\",\"areaCode\":\"350583\",\"hourList\":
[{\"weather_code\":\"07\",\"time\":\"202205242000\",\"area\":\"南安
\",\"wind_direction\":\"東南風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"20\"},
{\"weather_code\":\"07\",\"time\":\"202205242100\",\"area\":\"南安
\",\"wind_direction\":\"東風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"20\"},
{\"weather_code\":\"07\",\"time\":\"202205242200\",\"area\":\"南安
\",\"wind_direction\":\"東風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"20\"},
{\"weather_code\":\"07\",\"time\":\"202205242300\",\"area\":\"南安
\",\"wind_direction\":\"東風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"20\"},
{\"weather_code\":\"07\",\"time\":\"202205250000\",\"area\":\"南安
\",\"wind_direction\":\"南風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"21\"},
{\"weather_code\":\"07\",\"time\":\"202205250100\",\"area\":\"南安
\",\"wind_direction\":\"西風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"21\"},
{\"weather_code\":\"07\",\"time\":\"202205250200\",\"area\":\"南安
\",\"wind_direction\":\"西北風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"21\"},
{\"weather_code\":\"02\",\"time\":\"202205250300\",\"area\":\"南安
\",\"wind_direction\":\"西北風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"陰
\",\"areaid\":\"101230506\",\"temperature\":\"21\"},
{\"weather_code\":\"02\",\"time\":\"202205250400\",\"area\":\"南安
\",\"wind_direction\":\"西北風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"陰
\",\"areaid\":\"101230506\",\"temperature\":\"21\"},
{\"weather_code\":\"02\",\"time\":\"202205250500\",\"area\":\"南安
\",\"wind_direction\":\"西風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"陰
\",\"areaid\":\"101230506\",\"temperature\":\"21\"},
{\"weather_code\":\"07\",\"time\":\"202205250600\",\"area\":\"南安
\",\"wind_direction\":\"西北風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"21\"},
{\"weather_code\":\"07\",\"time\":\"202205250700\",\"area\":\"南安
\",\"wind_direction\":\"西北風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"21\"},
{\"weather_code\":\"07\",\"time\":\"202205250800\",\"area\":\"南安
\",\"wind_direction\":\"西北風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"21\"},
{\"weather_code\":\"07\",\"time\":\"202205250900\",\"area\":\"南安
\",\"wind_direction\":\"西南風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"22\"},
{\"weather_code\":\"07\",\"time\":\"202205251000\",\"area\":\"南安
\",\"wind_direction\":\"南風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"23\"},
{\"weather_code\":\"07\",\"time\":\"202205251100\",\"area\":\"南安
\",\"wind_direction\":\"東風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"24\"},
{\"weather_code\":\"07\",\"time\":\"202205251200\",\"area\":\"南安
\",\"wind_direction\":\"東風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"24\"},
{\"weather_code\":\"07\",\"time\":\"202205251300\",\"area\":\"南安
\",\"wind_direction\":\"東風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"25\"},
{\"weather_code\":\"07\",\"time\":\"202205251400\",\"area\":\"南安
\",\"wind_direction\":\"東南風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"25\"},
{\"weather_code\":\"07\",\"time\":\"202205251500\",\"area\":\"南安
\",\"wind_direction\":\"東南風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"25\"},
{\"weather_code\":\"07\",\"time\":\"202205251600\",\"area\":\"南安
\",\"wind_direction\":\"東南風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"24\"},
{\"weather_code\":\"07\",\"time\":\"202205251700\",\"area\":\"南安
\",\"wind_direction\":\"東南風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"23\"},
{\"weather_code\":\"07\",\"time\":\"202205251800\",\"area\":\"南安
\",\"wind_direction\":\"東南風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"23\"},
{\"weather_code\":\"07\",\"time\":\"202205251900\",\"area\":\"南安
\",\"wind_direction\":\"東南風\",\"wind_power\":\"0-3級微風 <5.4m/s\",\"weather\":\"小雨
\",\"areaid\":\"101230506\",\"temperature\":\"23\"}]}\n" +
"}";

//將JSON轉為標準Map結構
@Test
public void case1(){
Map<String, Object> jsonMap = JsonUtils.transferToMap(json);
System.out.println(jsonMap);
}
/**
* OGNL直接提取數據，Value為子JSON對象的情況
*/
@Test
public void case2(){
Map<String, Object> jsonMap = JsonUtils.transferToMap(json);
Map resBody = JsonUtils.getValue(json, "showapi_res_body", Map.class);
System.out.println(resBody);
}

/**
* OGNL直接提取數據，Value為標準字符串的情況
*/
@Test
public void case3(){
Map<String, Object> jsonMap = JsonUtils.transferToMap(json);
String value = JsonUtils.getValue(json, "showapi_res_body.area", String.class);
System.out.println(value);
}

/**
* OGNL直接提取數據，Value為標準字符串的情況，Value為數組的情況
*/
@Test
public void case4(){
Map<String, Object> jsonMap = JsonUtils.transferToMap(json);
List<Map> hourList = JsonUtils.getValue(json, "showapi_res_body.hourList",st.class);
System.out.println(hourList);
// 每一個集合對象都是List
for(Map hour : hourList){
System.out.println(hour);
}
}

/**
* 利用List語法獲取第6個時點天氣預報
*/
@Test
public void case5(){
Map<String, Object> jsonMap = JsonUtils.transferToMap(json);
String area = JsonUtils.getValue(json,"showapi_res_body.hourList[5].weather_code", String.class);
System.out.println(area);
}
}

posted @ 2022-05-30 09:32 [奮斗] 閱讀(2082) 評論(0) 收藏舉報

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青春由磨礪而出彩，人生因奮斗而升華

Json多層級動態結構數據解析

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青春由磨礪而出彩，人生因奮斗而升華

Json多層級動態結構數據解析

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