Java 通过 JSONObject 递归解析 JSON 以针对特定键获取值
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/21354546/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
提示：将鼠标放在中文语句上可以显示对应的英文。显示中英文
时间：2020-08-13 08:14:45 来源:igfitidea点击:
Recursively parsing JSON via JSONObject to fetch value against specific keys
提问by HungryForKnowledge
I have a complex JSON as below which I need to parser recursively. The end result of recursion is Map> type of object where key is the audience - name value and the inner map is Text-key, Title-value. This is just a part of the complete JSON.
我有一个复杂的 JSON，如下所示，我需要递归解析它。递归的最终结果是 Map> 类型的对象，其中 key 是受众 - 名称值，内部映射是 Text-key, Title-value。这只是完整 JSON 的一部分。
"sections": {
"1": {
"1": {
"1": {
"title": "xxx",
"text": "xxx",
"tags": {
"audience": {
"1": {
"name": "xxx",
"title": "xxx",
"id": "xxx"
}
},
"styleHint": {
"1": {
"name": "xxx",
"title": "xxx",
"id": "xxx"
}
}
}
},
"title": "xxx",
"text": "xxx",
"tags": {
"audience": {
"1": {
"name": "xxx",
"title": "xxx",
"id": "xxx"
}
},
"styleHint": {
"1": {
"name": "xxx",
"title": "xxx",
"id": "xxx"
}
}
}
},
"2": {
"title": "xxx",
"text": "xxx",
"tags": {
"audience": {
"1": {
"name": "xxx",
"title": "xxx",
"id": "xxx"
}
},
"styleHint": {
"1": {
"name": "xxx",
"title": "xxx",
"id": "xxx"
}
}
}
},
"title": "xxx",
"text": "xxx",
"tags": {
"audience": {
"1": {
"name": "xxx",
"title": "xxx",
"id": "xxx"
},
"2": {
"name": "xxx",
"title": "xxx",
"id": "xxx"
}
},
"styleHint": {
"1": {
"name": "xxx",
"title": "xxx",
"id": "xxx"
}
}
}
},
"2": {
"title": "xxx",
"text": "xxx",
"tags": {
"audience": {
"1": {
"name": "xxx",
"title": "xxx",
"id": "xxx"
}
},
"styleHint": {
"1": {
"name": "xxx",
"title": "xxx",
"id": "xxx"
}
}
},
"anchor":"xxx"
},
"3": {
"1": {
"title": "xxx",
"text": "xxx",
"tags": {
"audience": {
"tag": {
"name": "xxx",
"title": "xxx",
"id": "xxx"
}
},
"styleHint": {
"tag": {
"name": "xxx",
"title": "xxx",
"id": "xxx"
}
}
}
},
"title": "xxx",
"text": "xxx",
"tags": {
"audience": {
"1": {
"name": "xxx",
"title": "xxx",
"id": "xxxx"
}
},
"styleHint": {
"1": {
"name": "xx",
"title": "xxx",
"id": "xxxx"
}
}
}
}
}
I used JSONObject for this only to realise very late that iteration happens in reverse order :(
我使用 JSONObject 只是为了很晚才意识到迭代以相反的顺序发生:(
I tried to parse the whole structure recursively and reverse it to my benefit. BUt the order is going haywire :( :( mainly because of the text, title, snippet which follows the 2nd text,title and has 2 audience names. The text and title of that part get skipped due to which the whole order is compromised
我试图递归解析整个结构并将其反转对我有利。但是订单正在失控:( :( 主要是因为文本、标题、片段跟在第二个文本、标题和有 2 个受众名称之后。由于整个订单受到损害，该部分的文本和标题被跳过
Please help !! my current implementation is as below
请帮忙 ！！我目前的实现如下
private Map<String, Map<String, String>> parseTextAndTitle(JSONObject json,
Map<String, Map<String, String>> ttMap, String article,
List<String> usrGrp) throws JSONException {
logger.info("Entering method..");
String userGroup = null;
Map<String, String> titleAndText = new LinkedHashMap<String, String>();
Map<String, String> currMap = new LinkedHashMap<String, String>();
Map<String, String> tempMap = new LinkedHashMap<String, String>();
Iterator<String> keys = json.sortedKeys();
while (keys.hasNext()) {
String key = keys.next();
JSONObject value = null;String firstKey = null;
String text = null;String title = null;
int length = 0;
try {
value = json.getJSONObject(key);
if (key.equalsIgnoreCase(STYLEHINT) || key.equalsIgnoreCase(ANCHOR)
|| key.equalsIgnoreCase(INLINE)) {
continue;
}
if (key.equals(TEXT)) {
text = json.getString(key);
text = removeHtmlTag(text);
logger.debug("TEXT RETRIEVED:" + text);
if(text != null) {
titleAndText.put(text, "");
}
else
logger.debug("Text not retrieved!!");
}
if (key.equals(TITLE)) {
title = json.getString(TITLE);
title = appendNewline(title);
logger.debug("TITLE RETRIEVED:" + title);
if (title != null) {
for (Map.Entry<String, String> iter : titleAndText
.entrySet())
firstKey = iter.getKey();
if(firstKey != null) {
titleAndText.put(firstKey, title);
}
else
logger.debug("NO key present in textAndTitle Map!!");
}
}
if (key.equals(AUDIENCE_TAG)) {
try {
length = value.length();
for (int i = 0; i < length; i++) {
userGroup = (String) value.getJSONObject(
String.valueOf(i + 1)).get(NAME);
logger.debug("USERGROUP RETRIEVED:" + userGroup);
usrGrp.add(userGroup);
}
} catch (Exception e) {
userGroup = (String) value.getJSONObject(TAG).get(NAME);
logger.debug("USERGROUP RETRIEVED:" + userGroup);
usrGrp.add(userGroup);
}
}
else{
parseTextAndTitle(value, ttMap, article, usrGrp);
}
} catch (Exception e) {
logger.debug("value not a JSON Object..rather an element");
// Extract the text values
if (key.equals(TEXT)) {
text = json.getString(key);
text = removeHtmlTag(text);
logger.debug("TEXT RETRIEVED:" + text);
if(text != null) {
titleAndText.put(text, "");
}
else
logger.debug("Text not retrieved!!");
}
if (key.equals(TITLE)) {
title = json.getString(TITLE);
title = appendNewline(title);
logger.debug("TITLE RETRIEVED:" + title);
if (title != null) {
for (Map.Entry<String, String> iter : titleAndText
.entrySet())
firstKey = iter.getKey();
if(firstKey != null) {
titleAndText.put(firstKey, title);
}
else
logger.debug("NO key present in textAndTitle Map!!");
}
}
}
if (!(usrGrp.isEmpty()) && !(titleAndText.isEmpty())
&& title != null) {
if(usrGrp.size() > 1)
{
for(int i=0;i<usrGrp.size();i++)
{
//If user group already present, extract current text,title map
//If not put usergroup as key, text,title map as value
if (ttMap.containsKey(usrGrp.get(i))) {
currMap = ttMap.get(usrGrp.get(i));
if (currMap.isEmpty()) {
ttMap.put(usrGrp.get(i), titleAndText);
} else {
currMap = ttMap.get(usrGrp.get(i));
for (Map.Entry<String, String> entry : currMap
.entrySet()) {
tempMap.put(entry.getKey(),
(String) entry.getValue());
}
for (Map.Entry<String, String> ttEntry : titleAndText
.entrySet()) {
tempMap.put(ttEntry.getKey(),
(String) ttEntry.getValue());
}
ttMap.put(usrGrp.get(i),tempMap);
// titleAndText = new LinkedHashMap<String, String>();
tempMap = new LinkedHashMap<String, String>();
}
}
else {
ttMap.put(usrGrp.get(i), titleAndText);
}
}
titleAndText.clear();
}
else
{
if (ttMap.isEmpty())
{
tempMap = titleAndText;
ttMap.put(usrGrp.get(0), tempMap);
}
else {
currMap = ttMap.get(usrGrp.get(0));
if (currMap.isEmpty()) {
ttMap.put(usrGrp.get(0), titleAndText);
}else {
currMap = ttMap.get(usrGrp.get(0));
for (Map.Entry<String, String> entry : currMap
.entrySet()) {
tempMap.put(entry.getKey(),
(String) entry.getValue());
}
for (Map.Entry<String, String> ttEntry : titleAndText
.entrySet()) {
tempMap.put(ttEntry.getKey(),
(String) ttEntry.getValue());
}
ttMap.put(usrGrp.get(0),tempMap);
titleAndText.clear();
}
}
}
usrGrp.clear();
}
}
logger.info("Exiting method..");
return ttMap;
}
采纳答案by HungryForKnowledge
Found a solution to the ordering..ditched JSONObject API and used gson JsonObject instead
找到了 ordering 的解决方案..ditched JSONObject API 并使用 gson JsonObject 代替
private Map<String, List<String>> parseJsonSection(
Map<String, List<String>> retTextMap, JsonObject jsonObject,
String lastKey, StringBuffer tt, List<String> ttext)
throws ParseException, JSONException {
for (Entry<String, JsonElement> entry : jsonObject.entrySet()) {
String key = entry.getKey();
Object value = entry.getValue();
logger.debug("Key:" + key + "\n" + value.toString());
if (key.equalsIgnoreCase(STYLEHINT) || key.equalsIgnoreCase(INLINE)
|| key.equalsIgnoreCase(ANCHOR))
continue;
if (key.equalsIgnoreCase(TEXT)) {
tt.append(value.toString());
ttext.add(tt.toString());
}
if (key.equalsIgnoreCase(TITLE) && tt.length() == 0) {
tt = new StringBuffer();
tt.append(value.toString() + "-");
}
if (key.equalsIgnoreCase(NAME)) {
logger.debug("Value of usergrp:" + value.toString());
String usrGrp = value.toString();
if (retTextMap.isEmpty()) {
if (tt.toString() != null) {
List<String> temp = new ArrayList<String>();
temp = ttext;
retTextMap.put(usrGrp, temp);
}
return retTextMap;
} else if (retTextMap.get(usrGrp) != null) {
List<String> temp = retTextMap.get(value.toString());
if (!temp.contains(tt.toString()))
temp.add(tt.toString());
retTextMap.put(usrGrp, temp);
} else if (retTextMap.get(usrGrp) == null) {
if (tt != null) {
List<String> temp = new ArrayList<String>();
temp.add(tt.toString());
retTextMap.put(usrGrp, temp);
return retTextMap;
}
}
}
if (value instanceof JsonObject) {
parseJsonSection(retTextMap, (JsonObject) value, key, tt, ttext);
}
}
return retTextMap;
}
回答by Hot Licks
Instead of
代替
while (keys.hasNext()) {
<blah blah>
if (key.equalsIgnoreCase(STYLEHINT) || key.equalsIgnoreCase(ANCHOR)
|| key.equalsIgnoreCase(INLINE)) {
continue;
}
if (key.equals(TEXT)) {
<blah blah>
}
if (key.equals(TITLE)) {
....
One can simply code:
一个可以简单地编码：
text = json.getString(TEXT);
<deal with text>
title = json.getString(TITLE);
<etc>
If it's possible that the some of the key values are not there, simply test for their absence with hasbefore fetching them.
如果某些键值可能不存在，只需has在获取它们之前测试它们是否存在。
Since STYLEHINT, ANCHOR, and INLINE are ignored, simply don't fetch them.
由于 STYLEHINT、ANCHOR 和 INLINE 被忽略，所以不要获取它们。
To handle the screwy layout of the JSON, do this:
要处理 JSON 的复杂布局，请执行以下操作：
if (json.has("title")) {
<extract title/text/tags/stylehint as described above>
}
else {
Iterator<String> keys = json.sortedKeys();
while (keys.hasNext()) {
// Note that "key" must be "1", "2", "3"...
String key = keys.next();
value = json.getJSONObject(key);
<recursively call method using "value">
}
}
回答by sklimkovitch
package Test.json;
import java.util.Iterator;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
public class App {
public static void main(String[] args) {
String str = "{\"a\":\"1\", \"b\":\"2\", \"c\":[{\"d\":\"4\"},{\"e\":\"5\"},{\"f\":[{\"g\":\"6\"},{\"h\":\"7\"}]}], \"i\":8}";
try {
loopThroughJson(new JSONObject(str));
} catch (JSONException e) {
e.printStackTrace();
}
}
public static void loopThroughJson(Object input) throws JSONException {
if (input instanceof JSONObject) {
Iterator<?> keys = ((JSONObject) input).keys();
while (keys.hasNext()) {
String key = (String) keys.next();
if (!(((JSONObject) input).get(key) instanceof JSONArray))
System.out.println(key + "=" + ((JSONObject) input).get(key));
else
loopThroughJson(new JSONArray(((JSONObject) input).get(key).toString()));
}
}
if (input instanceof JSONArray) {
for (int i = 0; i < ((JSONArray) input).length(); i++) {
JSONObject a = ((JSONArray) input).getJSONObject(i);
Object key = a.keys().next().toString();
if (!(a.opt(key.toString()) instanceof JSONArray))
System.out.println(key + "=" + a.opt(key.toString()));
else
loopThroughJson(a.opt(key.toString()));
}
}
}
}
Output:
a=1
b=2
d=4
e=5
g=6
h=7
i=8
回答by Ranjan
Modified @sklimkovitch code to get it working in some complex Json Structure...
修改了@sklimkovitch 代码以使其在一些复杂的 Json 结构中工作......
public void loopThroughJson(Object input) throws JSONException {
if (input instanceof JSONObject) {
Iterator<?> keys = ((JSONObject) input).keys();
while (keys.hasNext()) {
String key = (String) keys.next();
if (!(((JSONObject) input).get(key) instanceof JSONArray))
if (((JSONObject) input).get(key) instanceof JSONObject) {
loopThroughJson(((JSONObject) input).get(key));
} else
System.out.println(key + "=" + ((JSONObject) input).get(key));
else
loopThroughJson(new JSONArray(((JSONObject) input).get(key).toString()));
}
}
if (input instanceof JSONArray) {
for (int i = 0; i < ((JSONArray) input).length(); i++) {
JSONObject a = ((JSONArray) input).getJSONObject(i);
loopThroughJson(a);
}
}
}
