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Json多层级动态结构数据解析

一、工具

(1)GSON

Google Gson是一个简单的基于Java的库,用于将Java对象序列化为JSON,反之亦然。 它是由Google开发的一个开源库。

以下几点说明为什么应该使用这个库 -

  •  标准化 - Gson是一个由Google管理的标准化库。
  •  高效 - 这是对Java标准库的可靠,快速和高效的扩展。
  •  优化 - Gson库经过高度优化。
  •  支持泛型 - 它为泛型提供了广泛的支持。
  •  支持复杂的内部类 - 它支持具有深度继承层次结构的复杂对象。

(2)OGNL表达式

OGNL表达式是Object-Graph Navigation Language的缩写,是一种功能强大的表达式语言,通过

简单一致的表达式语法,可以存取对象的任意属性,调用对象的方法,遍历整个对象的结构图,实现字段类型转换。

二、mavan所需引入的依赖

<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、工具类

public class JsonUtils { 

/**
* 将指定JSON转为Map对象,Key固定为String,对应JSONkey
* Value分情况:
* 1. Value是字符串,自动转为字符串,例如:{"a","b"} 6 * 2. Value是其他JSON对象,自动转为Map,例如:{"a":{"b":"2"}}}
* 3. Value是数组,自动转为List<Map>,例如:{"a":[{"b":"2"},"c":"3"]}
* @param json 输入的JSON对象
* @return 动态的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;
}

/**
* 简化方法
* @param json 原始的JSON数据
* @param path OGNL规则表达式
* @param clazz Value对应的目标类
* @return clazz对应数据
*/
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、测试用例

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"

* }

* }

* }

* }

* }

*/

/**

* 超多层级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":"东南

风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"20"},

{"weather_code":"07","time":"202205242100","area":"南安","wind_direction":"东 风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"20"},

{"weather_code":"07","time":"202205242200","area":"南安","wind_direction":"东 风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"20"},

{"weather_code":"07","time":"202205242300","area":"南安","wind_direction":"东 风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"20"},

{"weather_code":"07","time":"202205250000","area":"南安","wind_direction":"南 风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"21"},

{"weather_code":"07","time":"202205250100","area":"南安","wind_direction":"西 风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"21"},

{"weather_code":"07","time":"202205250200","area":"南安","wind_direction":"西北

风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"21"},

{"weather_code":"02","time":"202205250300","area":"南安","wind_direction":"西北

风","wind_power":"0-3级 微风

<5.4m/s","weather":"阴","areaid":"101230506","temperature":"21"},

{"weather_code":"02","time":"202205250400","area":"南安","wind_direction":"西北

风","wind_power":"0-3级 微风

<5.4m/s","weather":"阴","areaid":"101230506","temperature":"21"},

{"weather_code":"02","time":"202205250500","area":"南安","wind_direction":"西 风","wind_power":"0-3级 微风

<5.4m/s","weather":"阴","areaid":"101230506","temperature":"21"},

{"weather_code":"07","time":"202205250600","area":"南安","wind_direction":"西北

风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"21"},

{"weather_code":"07","time":"202205250700","area":"南安","wind_direction":"西北

风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"21"},

{"weather_code":"07","time":"202205250800","area":"南安","wind_direction":"西北

风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"21"},

{"weather_code":"07","time":"202205250900","area":"南安","wind_direction":"西南

风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"22"},

{"weather_code":"07","time":"202205251000","area":"南安","wind_direction":"南 风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"23"},

{"weather_code":"07","time":"202205251100","area":"南安","wind_direction":"东 风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"24"},

{"weather_code":"07","time":"202205251200","area":"南安","wind_direction":"东 风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"24"},

{"weather_code":"07","time":"202205251300","area":"南安","wind_direction":"东 风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"25"},

{"weather_code":"07","time":"202205251400","area":"南安","wind_direction":"东南

风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"25"},

{"weather_code":"07","time":"202205251500","area":"南安","wind_direction":"东南

风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"25"},

{"weather_code":"07","time":"202205251600","area":"南安","wind_direction":"东南

风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"24"},

{"weather_code":"07","time":"202205251700","area":"南安","wind_direction":"东南

风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"23"},

{"weather_code":"07","time":"202205251800","area":"南安","wind_direction":"东南

风","wind_power":"0-3级 微风 <5.4m/s","weather":"小 雨","areaid":"101230506","temperature":"23"},

{"weather_code":"07","time":"202205251900","area":"南安","wind_direction":"东南

风","wind_power":"0-3级 微风 <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\":\"东南风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"20\"},

{\"weather_code\":\"07\",\"time\":\"202205242100\",\"area\":\"南安

\",\"wind_direction\":\"东风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"20\"},

{\"weather_code\":\"07\",\"time\":\"202205242200\",\"area\":\"南安

\",\"wind_direction\":\"东风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"20\"},

{\"weather_code\":\"07\",\"time\":\"202205242300\",\"area\":\"南安

\",\"wind_direction\":\"东风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"20\"},

{\"weather_code\":\"07\",\"time\":\"202205250000\",\"area\":\"南安

\",\"wind_direction\":\"南风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"21\"},

{\"weather_code\":\"07\",\"time\":\"202205250100\",\"area\":\"南安

\",\"wind_direction\":\"西风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"21\"},

{\"weather_code\":\"07\",\"time\":\"202205250200\",\"area\":\"南安

\",\"wind_direction\":\"西北风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"21\"},

{\"weather_code\":\"02\",\"time\":\"202205250300\",\"area\":\"南安

\",\"wind_direction\":\"西北风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"阴

\",\"areaid\":\"101230506\",\"temperature\":\"21\"},

{\"weather_code\":\"02\",\"time\":\"202205250400\",\"area\":\"南安

\",\"wind_direction\":\"西北风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"阴

\",\"areaid\":\"101230506\",\"temperature\":\"21\"},

{\"weather_code\":\"02\",\"time\":\"202205250500\",\"area\":\"南安

\",\"wind_direction\":\"西风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"阴

\",\"areaid\":\"101230506\",\"temperature\":\"21\"},

{\"weather_code\":\"07\",\"time\":\"202205250600\",\"area\":\"南安

\",\"wind_direction\":\"西北风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"21\"},

{\"weather_code\":\"07\",\"time\":\"202205250700\",\"area\":\"南安

\",\"wind_direction\":\"西北风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"21\"},

{\"weather_code\":\"07\",\"time\":\"202205250800\",\"area\":\"南安

\",\"wind_direction\":\"西北风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"21\"},

{\"weather_code\":\"07\",\"time\":\"202205250900\",\"area\":\"南安

\",\"wind_direction\":\"西南风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"22\"},

{\"weather_code\":\"07\",\"time\":\"202205251000\",\"area\":\"南安

\",\"wind_direction\":\"南风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"23\"},

{\"weather_code\":\"07\",\"time\":\"202205251100\",\"area\":\"南安

\",\"wind_direction\":\"东风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"24\"},

{\"weather_code\":\"07\",\"time\":\"202205251200\",\"area\":\"南安

\",\"wind_direction\":\"东风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"24\"},

{\"weather_code\":\"07\",\"time\":\"202205251300\",\"area\":\"南安

\",\"wind_direction\":\"东风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"25\"},

{\"weather_code\":\"07\",\"time\":\"202205251400\",\"area\":\"南安

\",\"wind_direction\":\"东南风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"25\"},

{\"weather_code\":\"07\",\"time\":\"202205251500\",\"area\":\"南安

\",\"wind_direction\":\"东南风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"25\"},

{\"weather_code\":\"07\",\"time\":\"202205251600\",\"area\":\"南安

\",\"wind_direction\":\"东南风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"24\"},

{\"weather_code\":\"07\",\"time\":\"202205251700\",\"area\":\"南安

\",\"wind_direction\":\"东南风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"23\"},

{\"weather_code\":\"07\",\"time\":\"202205251800\",\"area\":\"南安

\",\"wind_direction\":\"东南风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"23\"},

{\"weather_code\":\"07\",\"time\":\"202205251900\",\"area\":\"南安

\",\"wind_direction\":\"东南风\",\"wind_power\":\"0-3级 微风 <5.4m/s\",\"weather\":\"小雨

\",\"areaid\":\"101230506\",\"temperature\":\"23\"}]}\n" +

"}";

//将JSON转为标准Map结构

@Test

public void case1(){

Map<String, Object> jsonMap = JsonUtils.transferToMap(json);

System.out.println(jsonMap);

}

/**

* OGNL直接提取数据,Value为子JSON对象的情况

*/

@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直接提取数据,Value为标准字符串的情况

*/

@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直接提取数据,Value为标准字符串的情况,Value为数组的情况

*/

@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);

// 每一个集合对象都是List

for(Map hour : hourList){

System.out.println(hour);

}

}

/**

* 利用List语法获取第6个时点天气预报

*/

@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);

}

}

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