failed to parse the XML file in apex- gives null pointer exception error

Question

I'm trying to parse the below XML file:

<articles>
    <article>
        <source>EN-US</source>
        <target>SL</target>
        <id>ka1800000000eCYAAY</id>
        <publishstatus>Draft</publishstatus>
        <fields>
            <field name="BU_Type_SMB__c" xml:space="preserve" translate="false">false</field>
            <field name="BU_Type__c" xml:space="preserve" translate="false">RBU</field>
            <field name="BU_Type_text__c" xml:space="preserve" translate="false">HCP</field>
            <field name="Auto_Assignment_Rule_Enabled__c" xml:space="preserve"translate="false">false</field>
        </fields>
    </article>
</articles>

Code:

public void XMLClass() {        
    string xml = '<articles><article><source>EN-US</source><target>SL</target><id>ka1800000000eCYAAY</id><publishstatus>Draft</publishstatus><fields><field name="BU_Type_SMB__c" translate="false">false</field><field name="BU_Type__c" translate="false">RBU</field><field name="BU_Type_text__c" translate="false">HCP</field><field name="Auto_Assignment_Rule_Enabled__c" translate="false">false</field></fields></article></articles>';
    Dom.Document doc = new Dom.Document();
    doc.load(xml);
    //Retrieve the root element for this document.
    Dom.XMLNode soapWeather = doc.getRootElement();
    system.debug('------soapWeather------'+soapWeather);
    Dom.XMLNode OrderDetailId = soapWeather.getChildElement('article', null);
    string source = OrderDetailId.getChildElement('source', null).getText();
    system.debug('------source--------'+source);
    String articleSource = OrderDetailId.getChildElement('target', null).getText();
    String articleId = OrderDetailId.getChildElement('id', null).getText();
    String articlePublishstatus = OrderDetailId.getChildElement('publishstatus', null).getText();
    Dom.XMLNode fieldsList = OrderDetailId.getChildElement('fields', null).getChildElement('field',null);
    system.debug('------fieldsList--------'+fieldsList);
    Integer fieldCount = fieldsList.getAttributeCount();
    system.debug('------fieldCount-----'+fieldCount);
    String fieldName = fieldsList.getAttributeValue('name','');
    String fieldTranslate = fieldsList.getAttributeValue('translate','');
    string fieldvalue = fieldsList.getChildElement('field', null).getText();

    /*   list<Dom.XMLNode> fieldsNodeLst;
        for(Dom.XMLNode fields : fieldsList.getChildElements()){
            String fieldName = fields.getAttributeValue('name','');
            system.debug('------fieldName--------'+fieldName);
            String fieldTranslate = fields.getAttributeValue('translate','');
            fieldsNodeLst.add(new list<Dom.XMLNode> (fieldName,fieldTranslate));
        } */              
}

I'm getting null pointer exception in the below line-

string fieldvalue = fieldsList.getChildElement('field', null).getText();

How can I fix this error?

Answer 1

I have created class to store field values:

public class Field {
    public String text {get; set;}
    public String name {get; set;}
    public String translate {get; set;}
}

result of parsed fields would be stored in fields variable:

public void XMLClass(){
    String xml = '<articles><article><source>EN-US</source><target>SL</target><id>ka1800000000eCYAAY</id><publishstatus>Draft</publishstatus><fields><field name="BU_Type_SMB__c" translate="false">false</field><field name="BU_Type__c" translate="false">RBU</field><field name="BU_Type_text__c" translate="false">HCP</field><field name="Auto_Assignment_Rule_Enabled__c" translate="false">false</field></fields></article></articles>';
    Dom.Document doc = new Dom.Document();
    doc.load(xml);
    Dom.XMLNode soapWeather = doc.getRootElement();
    Dom.XMLNode orderDetailId = soapWeather.getChildElement('article', null);
    String source = OrderDetailId.getChildElement('source', null).getText();
    String articleSource = OrderDetailId.getChildElement('target', null).getText();
    String articleId = OrderDetailId.getChildElement('id', null).getText();
    String articlePublishstatus = OrderDetailId.getChildElement('publishstatus', null).getText();
    List<Dom.XMLNode> fieldsList = OrderDetailId.getChildElement('fields', null).getChildElements();
    List<Field> fields = parseFields(fieldsList);
    System.debug('fields:'+fields);
}

private List<Field> parseFields(List<Dom.XMLNode> fieldsList){
    List<Field> result = new List<Field>();
    for(Dom.XMLNode field :fieldsList){
        Field parsedField = new Field();
        parsedField.text = field.getText();
        parsedField.name = field.getAttribute('name', null);
        parsedField.translate = field.getAttribute('translate', null);
        result.add(parsedField);
    }
    return result;
}

Debug result:

DEBUG|fields:(Field:[name=BU_Type_SMB__c, text=false, translate=false], Field:[name=BU_Type__c, text=RBU, translate=false], Field:[name=BU_Type_text__c, text=HCP, translate=false], Field:[name=Auto_Assignment_Rule_Enabled__c, text=false, translate=false])