我正在尝试编写一个通用代码，它们是一个JSON数组，如下示例可以转换为地图。
这是示例。 父元素是菜单
{"menu": {
"items": [
{"id": "Open"},
{"id": "OpenNew", "label": "Open New"},
{"id": "ZoomIn", "label": "Zoom In"},
{"id": "ZoomOut", "label": "Zoom Out"},
{"id": "Quality"},
{"id": "Pause"}
]
}}
要映射的地图值为：
menu.items_0.id=open
menu.items_1.id=OpenNew
menu.items_1.label=Open New
menu.items_2.id=ZoomIn
menu.items_2.label=Zoom In
menu.items_3.id=ZoomOut
menu.items_3.id=Zoom Out
menu.items_4.id=Quality
menu.items_5.id=Pause
答案 0 :(得分：0)
对于我的答案，您需要这些课程：
org.json.JSONArray;
org.json.JSONException;
org.json.JSONObject;
我正在假设一个这样的类：
public class menu{
private String id;
private String label;
}
要解析-我忽略了它是否是流，文件等-。但是，假设您已经操纵了源代码来创建一个名为myString的长字符串对象。
JSONObject topLevel = new JSONObject( myString );
JSONObject itemsArray= topLevel.getJSONArray("items");
int tempID;
String tempLabel;
//Now go through all items in array.
for(int i =0; i < itemsArray.length(); i++){
tempID = itemsArray.getJSONObject(i).getString("id");
if(itemsArray.getJSONObject(i).has("label"))
tempLabel = itemsArray.getJSONObject(i).getString("label");
else
tempLabel = null;
//whatever action you need to take
menu = new menu( tempId, tempLabel);
}
答案 1 :(得分：0)
这里的代码可以完成工作。您可以提取一些方法，也可以对其进行一些重构，但这应该可以解决问题。
public class Example {
public static void main(String[] args) {
String source = "{\"menu\": {\"items\": [{\"id\": \"Open\"},{\"id\": \"OpenNew\", \"label\": \"Open New\"}, " +
"{\"id\": \"ZoomIn\", \"label\": \"Zoom In\"},"
+ "{\"id\": \"ZoomOut\", \"label\": \"Zoom Out\"},{\"id\": \"Quality\"},{\"id\": \"Pause\"}"
+ "]}}";
JSONObject jsonObject = new JSONObject(source);
Map<String, Object> map = jsonObject.toMap();
Map<String, String> resultMap = new HashMap<>();
map
.entrySet()
.forEach(entry -> addToResult(entry, resultMap, "", ""));
System.out.println(resultMap);
}
private static void addToResult(Map.Entry<String, Object> entry, Map<String, String> resultMap, String fieldNameAcummulator, String index) {
Object value = entry.getValue();
if (!Map.class.isAssignableFrom(value.getClass()) && !List.class.isAssignableFrom(value.getClass())) {
resultMap.put(addToAccumulator(entry, fieldNameAcummulator, index), (String) value);
return;
}
if (Map.class.isAssignableFrom(value.getClass())) {
Map<String, Object> nestedMap = (HashMap<String, Object>) value;
nestedMap
.entrySet()
.forEach(nestedEntry -> addToResult(nestedEntry, resultMap, addToAccumulator(entry, fieldNameAcummulator, index), ""));
} else {
List<HashMap<String, Object>> hashMaps = (List<HashMap<String, Object>>) value;
IntStream.range(0, hashMaps.size())
.forEach(listIndex -> {
HashMap<String, Object> nestedMap = hashMaps.get(listIndex);
nestedMap.entrySet().forEach(nestedEntry -> addToResult(nestedEntry, resultMap, addToAccumulator(entry, fieldNameAcummulator, index), String.valueOf(listIndex)));
});
}
}
private static String addToAccumulator(Map.Entry<String, Object> entry, String fieldNameAcummulator, String index) {
return fieldNameAcummulator.isEmpty()
? entry.getKey()
: fieldNameAcummulator + getKeyValueWithIndex(entry, index);
}
private static String getKeyValueWithIndex(Map.Entry<String, Object> entry, String index) {
return index.isEmpty()
? ".".concat(entry.getKey())
: "_".concat(index).concat(".").concat(entry.getKey());
}
}
随时询问您是否对实施有任何疑问。
希望有帮助！
答案 2 :(得分：0)
我已经更改了一些逻辑，然后可以正常工作。
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.json.JSONArray;
import org.json.JSONObject;
public class JsonToMapConvertor {
private static HashMap<String, Object> mapReturn = new HashMap<String, Object>();
public static JsonParser parser = new JsonParser();
public static void main(String[] args) throws Exception{
String json ="{\n" +
" \"glossary\": {\n" +
" \"title\": \"example glossary\",\n" +
" \"GlossDiv\": {\n" +
" \"title\": \"S\",\n" +
" \"GlossList\": {\n" +
" \"GlossEntry\": {\n" +
" \"ID\": \"SGML\",\n" +
" \"SortAs\": \"SGML\",\n" +
" \"GlossTerm\": \"Standard Generalized Markup Language\",\n" +
" \"Acronym\": \"SGML\",\n" +
" \"Abbrev\": \"ISO 8879:1986\",\n" +
" \"GlossDef\": {\n" +
" \"para\": \"A meta-markup language, used to create markup languages such as DocBook.\",\n" +
" \"GlossSeeAlso\": [\"GML\", \"XML\"]\n" +
" },\n" +
" \"GlossSee\": \"markup\"\n" +
" }\n" +
" }\n" +
" }\n" +
" }\n" +
"}";
HashMap<String, Object> map = createHashMapFromJsonString(json,"");
System.out.println("map size "+map.size());
for (Map.Entry<String, Object> entry : map.entrySet()) {
if(!entry.getValue().toString().contains("{"))
System.out.println(entry.getKey()+" : "+entry.getValue());
}
}
public static HashMap<String, Object> createHashMapFromJsonString(String json,String prefix) throws Exception{
if(json.startsWith("[",0)){
JSONArray jsonArray = new JSONArray(json);
for (int i = 0; i < jsonArray.length(); i++){
JSONObject jsonobject = jsonArray.getJSONObject(i);
createHashMapFromJsonString(jsonobject.toString(), prefix+"_"+i);
}
}
else{
JsonObject object = (JsonObject) parser.parse(json);
Set<Map.Entry<String, JsonElement>> set = object.entrySet();
Iterator<Map.Entry<String, JsonElement>> iterator = set.iterator();
while (iterator.hasNext()) {
Map.Entry<String, JsonElement> entry = iterator.next();
String key = entry.getKey();
if(prefix.length()!=0){
key = prefix + "."+key;
}
JsonElement value = entry.getValue();
if (null != value) {
if (!value.isJsonPrimitive()) {
if (value.isJsonObject()) {
mapReturn.put(key, createHashMapFromJsonString(value.toString(),key));
} else if (value.isJsonArray() && value.toString().contains(":")) {
List<HashMap<String, Object>> list = new ArrayList<>();
JsonArray array = value.getAsJsonArray();
if (null != array) {
for (JsonElement element : array) {
if (!element.isJsonPrimitive()) {
createHashMapFromJsonString(value.toString(),key);
}else{
list.add(createHashMapFromJsonString(value.toString(),key));
}
}
mapReturn.put(key, list);
}
} else if (value.isJsonArray() && !value.toString().contains(":")) {
mapReturn.put(key, value.getAsJsonArray());
}
} else {
mapReturn.put(key, value.getAsString());
}
}
}
}
return mapReturn;
}
}
答案 3 :(得分：0)
将JSONObject转换为通用Map列表的另一种方式
public static List<Map<String, Object>> getJsonNode(String jsonContents, String nodeName)
throws JsonProcessingException, IOException, ParseException {
JSONParser parser = new JSONParser();
JSONObject json = (JSONObject) parser.parse(jsonContents);
Object o = json.get(nodeName);
List<Map<String, Object>> results = Lists.newArrayList();
if (o instanceof JSONObject) {
results.add((Map<String, Object>) o);
} else if (o instanceof JSONArray) {
List<Map<String, Object>> hashMaps = (List<Map<String, Object>>) o;
results.addAll((Collection<? extends Map<String, Object>>) hashMaps);
}
return results;
}
/**
* Driver
*
* @param args
* @throws IOException
* @throws ParseException
*/
public static void main(String[] args) throws IOException, ParseException {
String jsonInputFile = "temp/input.json";
String jsonContents = new String(Files.readAllBytes(Paths.get(jsonInputFile)));
List<Map<String, Object>> results = getJsonNode(jsonContents, "summary");
for (Map<String, Object> entry : results) {
System.out.println(entry);
}
///////////////////////////////////////
results = getJsonNode(jsonContents, "payWay");
for (Map<String, Object> entry : results) {
System.out.println(entry);
}
///////////////////////////////////////
results = getJsonNode(jsonContents, "sellerDetails");
for (Map<String, Object> entry : results) {
System.out.println(entry);
}
}