读取哈希映射嵌套属性动态地。

huangapple
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英文:

Read hashmap nested properties dynamically

问题

我有以下JSON：

  1. "total":"2",
  2. "offset":"1",
  3. "limit":"2",
  4. "results":[{
  5.     "code":1,
  6.     "title":"RESTAURANTE SADOCHE",
  7.     "contact":{
  8.         "code":10,
  9.         "name":"HENRIQUE BARBALHO",
  10.         "company":{
  11.             "code":100,
  12.             "name":"RESTAURANTE SADOCHE LTDA-ME"
  13.         }
  14.     }
  15. },
  16. {
  17.     "code":2,
  18.     "title":"ARNALDO GRILL",
  19.     "contact":{
  20.         "code":20,
  21.         "name":"FÁTIMA COSTA",
  22.         "company":{
  23.             "code":200,
  24.             "name":"COSTA NATAL RESTAURANTE EIRELI"
  25.         }
  26.     }
  27. }]

我使用Gson库将此JSON转换为Java HashMap：

  1. Map<String, Object> retMap = new Gson().fromJson(jsonUpString, new TypeToken<HashMap<String, Object>>(){}.getType());

我需要动态读取此创建的哈希映射的某些属性。例如：标题，联系人的姓名和公司的名称。

有时，这些属性（标题，联系人的姓名和公司的名称）可能在列表中。

以下是我的代码：

  1. String propertyName = "name";
  2. String nesting = "results;contact;company";
  3. String[] levels = nesting.split(";");
  5. Map map = new HashMap();
  6. map = retMap;
  8. for (int i = 0; i < niveis.length; i++) {                        
  9.     map = (Map)map.get(levels[i]);        
  10.     System.out.println(map);
  12.     if (i == levels.length - 1) {
  13.         System.out.println(map.get(propertyName));
  14.     }
  15. }

但是，如果属性（results，contact或company）返回多个对象，JSON会将它们作为列表返回，我无法获取所需的信息。

英文:

I have the JSON below:

  1. &quot;total&quot;:&quot;2&quot;,
  2. &quot;offset&quot;:&quot;1&quot;,
  3. &quot;limit&quot;:&quot;2&quot;,
  4. &quot;results&quot;:[{    
  5.     &quot;code&quot;:1,
  6.     &quot;title&quot;:&quot;RESTAURANTE SADOCHE&quot;,
  7.     &quot;contact&quot;:{
  8.         &quot;code&quot;:10,
  9.         &quot;name&quot;:&quot;HENRIQUE BARBALHO&quot;,
  10.         &quot;company&quot;:{
  11.             &quot;code&quot;:100,
  12.             &quot;name&quot;:&quot;RESTAURANTE SADOCHE LTDA-ME&quot;
  13.         }
  14.     }
  15. },
  16. {
  17.     &quot;code&quot;:2,
  18.     &quot;title&quot;:&quot;ARNALDO GRILL&quot;,
  19.     &quot;contact&quot;:{
  20.         &quot;code&quot;:20,
  21.         &quot;name&quot;:&quot;F&#193;TIMA COSTA&quot;,
  22.         &quot;company&quot;:{
  23.             &quot;code&quot;:200,
  24.             &quot;name&quot;:&quot;COSTA NATAL RESTAURANTE EIRELI&quot;
  25.         }
  26.     }
  27. }]

I turned this JSON into a Java HashMap using the Gson library.

  1. Map&lt;String, Object&gt; retMap = new Gson().fromJson(jsonUpString, new TypeToken&lt;HashMap&lt;String, Object&gt;&gt;(){}.getType());

I need to dynamically read some properties of this created hashmap. Ex: title, name of contact and name of company.

Sometimes these properties (title, name of contact and name of company) can be inside lists.

Below my code:

  1. String propertyName = &quot;name&quot;;
  2. String nesting = &quot;results;contact;company&quot;;
  3. String[] levels = nesting.split(&quot;;&quot;);
  5. Map map = new HashMap();
  6. map = retMap;
  8. for (int i = 0; i &lt; niveis.length; i++) {                        
  9.     map = (Map)map.get(levels[i]);        
  10.     System.out.println(map);
  12.     if (i == levels.length - 1) {
  13.         System.out.println(map.get(propertyName));
  14.     }
  15. }

But if the properties (results, contact or company) return more than one object, the JSON returns them as lists, and I can't get the information I need.

答案1

得分: 0

我使用以下方式解决了这个问题...

  1. private static void leJSON(Object object) {
  2.     if (object instanceof JSONObject) {
  3.         Set<String> ks = ((JSONObject) object).keySet();
  4.         for (String key : ks) {
  5.             Object value = ((JSONObject) object).get(key);
  6.             if (value != null) {
  7.                 System.out.printf("%s=%s (%s)\n", key, value, value.getClass().getSimpleName());
  8.                 if (value.getClass().getSimpleName().equalsIgnoreCase("JSONArray")) {
  9.                     JSONArray ja = (JSONArray) value;
  10.                     for (int i = 0; i < ja.size(); i++) {
  11.                         leJSON(ja.get(i));
  12.                     }
  13.                 }
  14.                 if (value.getClass().getSimpleName().equalsIgnoreCase("JSONObject")) {
  15.                     leJSON(value);
  16.                 }
  17.             }
  18.         }
  19.     }
  20. }
  22. 主方法...
  24. String json = "{...}";
  25. JSONObject object = (JSONObject) JSONValue.parse(jsonString2);
  26. leJSON(object);
英文:

I solved the problem using...

  1. private static void leJSON(Object object) {
  2.     if (object instanceof JSONObject) {
  3.         Set &lt; String &gt; ks = ((JSONObject) object).keySet();
  4.         for (String key: ks) {
  5.             Object value = ((JSONObject) object).get(key);
  6.             if (value != null) {
  7.                 System.out.printf(&quot;%s=%s (%s)\n&quot;, key, value, value.getClass().getSimpleName());
  8.                 if (value.getClass().getSimpleName().equalsIgnoreCase(&quot;JSONArray&quot;)) {
  9.                     JSONArray ja = (JSONArray) value;
  10.                     for (int i = 0; i &lt; ja.size(); i++) {
  11.                         leJSON(ja.get(i));
  12.                     }
  13.                 }
  14.                 if (value.getClass().getSimpleName().equalsIgnoreCase(&quot;JSONObject&quot;)) {
  15.                     leJSON(value);
  16.                 }
  17.             }
  18.         }
  19.     }
  20. }

main method...

  1. String json = &quot;{...}&quot;;
  2. JSONObject object = (JSONObject) JSONValue.parse(jsonString2);        
  3. readJSON(object);

huangapple
  • 本文由 发表于 2020年8月7日 03:50:50
  • 转载请务必保留本文链接：https://go.coder-hub.com/63290802.html
  • java
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