问题描述
我正在尝试使用最高效的内存和高性能方法在 JSON 架构中查找任何元素的 type。然而，在达到某个点后，我有点卡住了，没有想法了，所以希望在这里得到答案：
基本上，我有一个 List: jsonPath，它将由元素及其父元素组成，我需要从我拥有的 Json Schema 中识别出其类型。为了解析 Json Schema，我使用了 Java Jackson Library。我能够获得所有元素并能够找到它的类型，但在比较过程中，我有点困惑。
以下是我到目前为止的代码：
正如我们所见，我将 jsonPath 设为 "food","Ingredients","ingredient"，这意味着我需要找到最后一个元素 type 的 ingredient，其他元素是它的父元素。程序应将 type 返回为 array。同样，如果我在 jsonPath array 中传递任何其他元素，例如 food 或 price，那么它应该检查相应的父母和他们的孩子，然后最后应该返回它的类型。我使用了 Stack elements 仅供参考，您可以忽略它。
我可以尝试在每个阶段添加多个 if 条件并获取元素类型。但是，我试图找到一种简单且更好的方法，而不是使用复杂的嵌套 if。应该可以以更简单的方式完成，但目前对我来说没有任何点击。
public class JsonElementLocator {
private final JsonNode outerNode;
private static JsonElementLocator _instance;
// Default constructor to get the content and store in the root
private JsonElementLocator() throws IOException {
final ObjectMapper mapper = new ObjectMapper();
final JsonNode root = mapper.readTree(JsonElementLocator.class.getClassLoader().getResource("testJSON.json"));
outerNode = root.path("deFinitions");
}
// Method to create a Object instance of current class
private static synchronized JsonElementLocator getInstance() throws IOException {
if (_instance == null) {
_instance = new JsonElementLocator();
}
return _instance;
}
// Method called by other application to get the element Type
public static Optional < String > locate(List < String > elementPath) throws IOException {
JsonElementLocator cl = getInstance();
JsonNode rootNode = cl.outerNode;
recurse(rootNode,new Stack < String > ());
return Optional.empty();
}
// Method called recursively to get the element Type from JSON Schema
private static Optional < String > recurse(JsonNode rootNode,Stack < String > elements) {
// Loop through each Object in Root Node
for (JsonNode childNode: rootNode) {
// Check if childNode is of Object type
if (childNode.path("type").toString().contains("object")) {
elements.push(childNode.get("title").toString());
// Call recurse method for the subsequent objects
recurse(childNode.path("properties"),elements);
elements.pop();
} else if (childNode.path("type").toString().contains("array")) {
// Check if childNode is of Array type and call its elements
for (JsonNode ccNode: childNode.path("items")) {
final String def = ccNode.toString().contains("deFinitions") ? ccNode.toString().replace("\"","").replaceAll("#/deFinitions/","") : null;
// Find the element from the root
if (def != null) {
final JsonNode defInfo = _instance.outerNode.get(def);
// Call recurse method for deFinition elements
recurse(defInfo.path("properties"),elements);
}
}
} else {
System.out.println(String.join("/",elements));
// Check if childNode is of normal type
}
}
return Optional.empty();
}
public static void main(String[] args) throws IOException {
List < String > jsonPath = new ArrayList < String > (List.of("food","ingredient"));
locate(jsonPath);
}
}
以下是我试图解析的完整 Json Schema：
{
"$schema": "http://json-schema.org/draft-06/schema#","$ref": "#/deFinitions/Welcome2","deFinitions": {
"Welcome2": {
"type": "object","additionalProperties": false,"properties": {
"hotelName": {
"type": "string"
},"food": {
"type": "array","items": {
"$ref": "#/deFinitions/Food"
}
}
},"required": [
"food","hotelName"
],"title": "Welcome2"
},"Food": {
"type": "object","properties": {
"name": {
"type": "string"
},"price": {
"type": "string"
},"description": {
"type": "string"
},"calories": {
"type": "string","format": "integer"
},"ingredients": {
"$ref": "#/deFinitions/Ingredients"
}
},"required": [
"calories","description","ingredients","name","price"
],"title": "Food"
},"Ingredients": {
"type": "object","properties": {
"ingredient": {
"type": "array","items": {
"type": "string"
}
}
},"required": [
"ingredient"
],"title": "Ingredients"
}
}
}
解决方法
在尝试了很多事情之后，我能够做到。添加代码作为答案，因为它可以帮助将来尝试实现类似目标的人：
import java.io.IOException;
import java.util.List;
import java.util.Optional;
import java.util.Stack;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
public class TypeLocator {
private final JsonNode outerNode;
private static TypeLocator _instance;
private final JsonNode root;
// Default constructor to get the content and store in the root
private TypeLocator() throws IOException {
// Create the jackson instance and get the JSON Schema Information
final ObjectMapper mapper = new ObjectMapper();
root = mapper.readTree(TypeLocator.class.getClassLoader().getResource("JSON-Schema.json"));
outerNode = root.path("definitions");
}
// Method to create a Object instance of current class
private static synchronized TypeLocator getInstance() throws IOException {
if (_instance == null) {
_instance = new TypeLocator();
}
return _instance;
}
// Method called by other application to get the element Type
public static Optional<String> locate(List<String> elementPath) throws IOException {
// Get the JSON Schema information
TypeLocator cl = getInstance();
JsonNode rootNode = cl.outerNode;
// Check if there are element and obtain the event type info
final String eventType = elementPath.get(0).substring(0,1).toLowerCase() + elementPath.get(0).substring(1);
final JsonNode eventInfo = rootNode.get(eventType);
elementPath.remove(0);
if (elementPath.size() > 0) {
// Loop through elements in particular event Type and get type
for (JsonNode allOf : eventInfo) {
for (JsonNode allElements : allOf) {
Optional<String> type = recurse(allElements,new Stack<String>(),elementPath);
if (type.isPresent()) {
return type;
}
}
}
}
return Optional.empty();
}
private static Optional<String> recurse(JsonNode node,Stack<String> elements,List<String> elementPath) {
// Check if its Reference type
if (node.get("$ref") != null) {
// Check if the element has reference to other definition
final String ref = node.toString().contains("definitions") ? node.get("$ref").toString().replace("\"","").replaceAll("#/definitions/","") : null;
// Check if the Reference is null
if (ref != null) {
final JsonNode refElements = _instance.outerNode.get(ref);
return recurse(refElements,elements,elementPath);
}
} else if (node.get("items") != null && elementPath.size() > 0) {
// Check if the element has Array type with items
final String ref = node.get("items").toString().contains("definitions") ? node.get("items").get("$ref").toString().replace("\"","")
.replaceAll("#/definitions/","") : null;
if (elementPath.size() > 0 && elementPath.get(0).equals(ref)) {
elementPath.remove(0);
final JsonNode refElements = _instance.outerNode.get(ref);
return recurse(refElements,elementPath);
}
} else if (node.get("properties") != null && elementPath.size() > 0) {
// Check if the element has properties if no recurse through properties
final JsonNode prop = node.get("properties");
if (elementPath.size() > 0 && prop.get(elementPath.get(0)) != null) {
final JsonNode elementInfo = prop.path(elementPath.get(0));
elementPath.remove(0);
return recurse(elementInfo,elementPath);
}
} else if (node.path("type") != null && elementPath.size() == 0) {
// If the element has type then return the final Type
return Optional.of(node.get("type").toString());
} else {
// If the element is not found then directly check
}
return Optional.empty();
}
}