使用XML填充JComboBox - 缺少一些東西

Question

這是我的一次。 我有以下XML文件：

<?xml version="1.0"?> 
<components> 
    <resources> 
     <resource id="House"> 
      <id>int</id> 
      <type>string</type> 
      <maxUsage>float</maxUsage> 
      <minUsage>float</minUsage> 
      <averageUsage>float</averageUsage> 
     </resource> 
     <resource id="Commerce"> 
      <id>int</id> 
      <type>string</type> 
      <maxUsage>float</maxUsage> 
      <minUsage>float</minUsage> 
      <averageUsage>float</averageUsage> 
     </resource> 
     <resource id="Industry"> 
      <id>int</id> 
      <type>string</type> 
      <maxUsage>float</maxUsage> 
      <minUsage>float</minUsage> 
      <averageUsage>float</averageUsage> 
     </resource> 
    </resources> 
    <agregatorsType1> 
     <agregator1 id="CSP"> 
      <id>int</id> 
      <type>string</type> 
     </agregator1> 
     <agregator1 id="Microgrid">  
      <id>int</id> 
      <type>string</type> 
     </agregator1> 
    </agregatorsType1> 
    <soagregatorsType0> 
     <agregator0 id="VPP"> 
      <id>int</id> 
      <type>string</type> 
     </agregator0> 
    </agregatorsType0> 
</components> 

，我想填充的JComboBox與每個資源（院，工商）的ID的。

我有以下方法：

public static String[] readResourcesXML(String fileName) throws IOException, ClassNotFoundException, Exception { 


//Gets XML 
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); 
DocumentBuilder docBuilder = factory.newDocumentBuilder(); 
Document documento = docBuilder.parse(fileName); 

//Searches all text 
documento.getDocumentElement().normalize(); 

//Gets elements from xml 
Element raiz = documento.getDocumentElement(); 
NodeList listaResources = raiz.getElementsByTagName("resources"); 

//Search all resources 
int tam = listaResources.getLength(); 
String[] vecResources = new String[tam]; 

for (int i = 0; i < tam; i++) { 
    Element elem = (Element) listaResources.item(i);   
    vecResources[i] = elem.getAttribute("/resource/@id"); 
} 
    //returns an array with all the id's of the resources 
    return vecResources; 
} 

注：該字符串文件名具有以下值： 「SRC \ CONFIGS \ features.xml」

的問題是，JComboBox可總是空的。我錯過了什麼？

感謝）

Answer 1

Element#getAttribute檢索屬性直接從Elements而不是從嵌套元素。您需要遍歷resource代替：

NodeList listaResources = raiz.getElementsByTagName("resource"); 

int tam = listaResources.getLength(); 
String[] vecResources = new String[tam]; 

for (int i = 0; i < tam; i++) { 
    Element elem = (Element) listaResources.item(i);  
    System.out.println(elem); 
    vecResources[i] = elem.getAttribute("id"); // change to id 
}