大佬教程收集整理的这篇文章主要介绍了是否有可能使用 Jackson JsonParser，大佬教程大佬觉得挺不错的，现在分享给大家，也给大家做个参考。
我正在尝试使用 Jackson JsonParser 从一个大型 JsON 文件中一一读取事件。我想将每个事件临时存储在一个对象中，例如 JsonObject 或任何其他我以后想要用于进一步处理的对象。
我之前是一一读取 JsON 事件并将它们存储到我自己的自定义上下文中：Old Post for JACKSON JsonParser Context 工作正常。但是，我想将它们一一存储到 JsonObject 或其他对象中，而不是上下文。
以下是我的示例 JsON 文件：
@H_674_14@{
"@context":"https://context.org/context.jsonld","isA":"SchoolManagement","format":"application/ld+Json","scheR_170_11845@aVersion":"2.0","creationDate":"2021-04-21T10:10:09+00:00","body":{
"members":[
{
"isA":"student","name":"ABCS","class":10,"coaching":[
"XSJsJ","IIIRIRI"
],"dob":"1995-04-21T10:10:09+00:00"
},{
"isA":"teacher","department":"computer scIEnce","school":{
"name":"ABCD School"
},{
"isA":"boardMember","board":"schoolboard","dob":"1995-04-21T10:10:09+00:00"
}
]
}
}
有时我只想在我的 @H_736_3@member 中存储一个 student，例如 teacher 或 JsonObject。
以下是我到目前为止的代码： 将每个事件存储在一个对象中的最佳方法是什么，我以后可以使用它进行一些处理。 然后再次清除该对象并将其用于下一个事件？
@H_674_14@public class Main {
private JsONObject evenTinfo;
private final String[] eventTypes = @R_874_3320@[] { "student","teacher","boardMember" };
public static voID main(String[] args) throws JsonParseException,JsonMapPingException,IOException,JAXBException,URISyntaxException {
// Get the JsON Factory and parser Object
JsonFactory JsonFactory = new JsonFactory();
JsonParser JsonParser = JsonFactory.createParser(new file(Main.class.getClassLoader().getresource("inputJson.Json").toURI()));
JsonToken current = JsonParser.nextToken();
// check the first element is Object
if (current != JsonToken.START_OBjeCT) {
throw new IllegalStateException("Expected content to be an array");
}
// Loop until the start of the EPCIS EventList array
while (JsonParser.nextToken() != JsonToken.START_ARRAY) {
System.out.println(JsonParser.getCurrentToken() + " --- " + JsonParser.getCurrentname());
}
// Goto the next token
JsonParser.nextToken();
// Call the method to loop until the end of the events file
eventTraverser(JsonParser);
}
// Method which will traverse through the eventList and read event one-by-one
private static voID eventTraverser(JsonParser JsonParser) throws IOException {
// Loop until the end of the EPCIS events file
while (JsonParser.nextToken() != JsonToken.END_OBjeCT) {
//Is there a possibility to store the complete object directly in an JsON Object or I need to again go through every token to see if is array and handle it accordingly as mentioned in my prevIoUs POST.
}
}
}
在尝试了一些东西后，我能够让它工作。我发布了整个代码，因为它可能对将来的某个人有用，因为我知道找到合适的工作代码示例是多么令人沮丧：
@H_674_14@public class Main
{
public void xmlConverter (InputStream jsonStream) throws IOException,JAXBException,XMLStreamException
{
// jsonStream is the input JSOn which is normally passed by reading the JSON file
// Get the JSON Factory and parser Object
final JsonFactory jsonFactory = new JsonFactory ();
final JsonParser jsonParser = jsonFactory.createParser (jsonStream);
final ObjectMapper objectMapper = new ObjectMapper ();
//To read the duplicate keys if there are any key duplicate json
final SimpleModule module = new SimpleModule ();
module.addDeserializer (JsonNode.class,new JsonNodeDupeFieldHandlingDeserializer ());
objectMapper.registerModule (modulE);
jsonParser.setCodec (objectMapper);
// check the first element is Object if not then invalid JSON throw error
if (jsonParser.nextToken () != JsonToken.START_OBjeCT)
{
throw new IllegalStateException ("Expected content to be an array");
}
while (!jsonParser.getText ().equals ("members"))
{
//Skipping the elements till members key
// if you want you can do some process here
// I am skipping for now
}
// Goto the next token
jsonParser.nextToken ();
while (jsonParser.nextToken () != JsonToken.END_ARRAY)
{
final JsonNode jsonNode = jsonParser.readValueAsTree ();
//check if the JsonNode is valid if not then exit the process
if (jsonNode == null || jsonNode.isNull ())
{
System.out.println ("End Of File");
break;
}
// Get the eventType
final String eventType = jsonNode.get ("isA").asText ();
// Based on eventType call different type of class
switch (eventTypE)
{
case "student":
final student studenTinfo =
objectMapper.treeToValue (jsonNode,student.class);
//I was calling the JAXB Method as I was doing the JSON to XML Conversion
xmlCreator (studenTinfo,student.class);
break;
case "teacher":
final Teacher teacherInfo =
objectMapper.treeToValue (jsonNode,Teacher.class);
xmlCreator (teacherInfo,Teacher.class);
break;
}
}
}
//Method to create the XML using the JAXB
private void xmlCreator (Object evenTinfo,Class eventTypE) throws JAXBException
{
private final StringWriter sw = @R_874_3320@Writer ();
// Create JAXB Context object
JAXBContext context = JAXBContext.newInstance (eventTypE);
// Create Marshaller object from JAXBContext
Marshaller marshaller = context.createMarshaller ();
// Print formatted XML
marshaller.setProperty (Marshaller.JAXB_FORMATTED_OUTPUT,Boolean.TRUE);
// Do not add the <xml> version tag
marshaller.setProperty (Marshaller.JAXB_FRAGMENT,Boolean.TRUE);
// XmlSupportExtension is an interface that every class such as student Teacher implements
// xmlSupport is a method in XmlSupportExtension which has been implemented in all classes
// Create the XML based on type of incoming event type and store in SW
marshaller.marshal (((XmlSupportExtension) evenTinfo).xmlSupport (),sw);
// Add each event within the List
eventsList.add (sw.toString ());
// Clear the StringWritter for next event
sw.getBuffer ().setLength (0);
}
}
这是覆盖 JACKSON 类的类。 如果您的 Json 具有重复的 JSON 密钥，则可以使用此方法。如果您需要，请关注此帖子以获得完整的说明。如果不需要，请跳过此部分并从上述类中删除代码 @H_736_3@module 部分： Jackson @JsonAnySetter ignores values of duplicate key when used with Jackson ObjectMapper treeToValue method
@H_674_14@
@JsonDeserialize(using = JsonNodeDupeFieldHandlingDeserializer.class)
public class JsonNodeDupeFieldHandlingDeserializer extends JsonNodeDeserializer {
@Override
protected void _handleDuplicateField(JsonParser p,DeserializationContext ctxt,JsonNodeFactory nodeFactory,String fieldName,ObjectNode objectNode,JsonNode oldValue,JsonNode newvalue) {
ArrayNode asArrayValue = null;
if (oldValue.isArray()) {
asArrayValue = (ArrayNodE) oldValue;
} else {
asArrayValue = nodeFactory.arrayNode();
asArrayValue.add(oldvalue);
}
asArrayValue.add(newvalue);
objectNode.set(fieldName,asArrayvalue);
}
}
以上是大佬教程为你收集整理的是否有可能使用 Jackson JsonParser全部内容，希望文章能够帮你解决是否有可能使用 Jackson JsonParser所遇到的程序开发问题。
如果觉得大佬教程网站内容还不错，欢迎将大佬教程推荐给程序员好友。
本图文内容来源于网友网络收集整理提供，作为学习参考使用，版权属于原作者。
如您有任何意见或建议可联系处理。小编QQ：384754419，请注明来意。