將XML元素計數保存爲字符串

Question

如何用java來計算此xml片段中PolylinePoint元素的數量（對您很重要的是，這個xml不是文件而是字符串） ：

<LocationInformationRequest> 
      <InitialInput> 
       <GeoRestriction> 
        <Area> 
         <PolylinePoint> 
          <Longitude>88.1</Longitude> 
          <Latitude>88.2</Latitude> 
          <Altitude>88.3</Altitude> 
         </PolylinePoint> 
         <PolylinePoint> 
          <Longitude>88.4</Longitude> 
          <Latitude>88.5</Latitude> 
          <Altitude>88.6</Altitude> 
         </PolylinePoint> 
         <PolylinePoint> 
          <Longitude>88.7</Longitude> 
          <Latitude>88.8</Latitude> 
          <Altitude>88.9</Altitude> 
         </PolylinePoint> 
        </Area> 
       </GeoRestriction> 
      </InitialInput> 
     </LocationInformationRequest> 

用xml作爲文件很容易解決這個問題。但是對於一個字符串來說它更難。有任何想法嗎？

感謝您的幫助！

Answer 1

• 我想你想解析你的字符串爲XML？這裏解釋： In Java, how do I parse XML as a String instead of a file?

• 另一種解決方案，但真正醜陋：如果你是100％肯定你的XML結構的（並且確保它不會改變），你可能也有計數的「<PolylinePoint」號

Answer 2

您可以使用正則表達式：

 String str="<PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint><PolylinePoint><Longitude>88.7</Longitude><Latitude>88.8</Latitude><Altitude>88.9</Altitude></PolylinePoint>"; 
     Pattern p = Pattern.compile("<PolylinePoint>"); 
     Matcher m=p.matcher(str); 
     int res=0; 
     while (m.find()) { 
      res++; 
     } 
     System.out.println(res++); 

Answer 3

如何創建文檔DROM字符串？

Document document = builder.parse（new InputSource（new StringReader（xmlString）））;

然後你可以很容易地使用xPath。