java中dom解析xml

从xml文件中得到某个节点中value的值，条件是已知道某一个子节点的参数，如下一片段，

已知 <name> 为 “Motor hand”的值，想从整个xml文件中得到此子节点的<value>所对应的值。

“<field>
<name>Motor hand</name>
<value>Right</value>
<type>Dotted</type>
</field>”

此方法是dom 遍历，获取大的节点并解析出子节点并属性和值一起存入到map中，将所有大节点再加入到链表中以备之后的其他程序调用（另附，从文件读取xml文件的方法）：

public static void main(String[] args) 
    {
        //"strxml"是 xml 转的string,  是个完整的xml对应的字符串，
 3      String result=findbynode(strxml,"field","name","Motor hand","value");

 4      System.out.print(result);

    //得到的结果是“Right”

         
    }
 
/**
 * common method "findbynode" get target from Xml 2
 * 
 * @param args example:
 * 
 * {
 * <field>     //field-->bignode
 *    <name>Motor hand</name> //name-->clum1 , "Motor hand"-->itemvalue
 *    <value>Right</value>    //value-->clum2
 *    <type>Dotted</type>
 * </field>
 *  }
 *  
 */
public static String  findbynode(String passxmlstr,String bignode,String clum1,String itemvalue,String clum2)
{  
    String result="";
    
    /*
    bignode="field";
    clum1="name";
    clum2="value";
    */
    
    ArrayList<Map> al=paserxmlbynode(passxmlstr,bignode);
    for(Map m : al)
    { 
        if(m.containsKey(clum1)&&m.get(clum1).toString().equals(itemvalue))
         {
             result=m.get(clum2).toString();
             break;
         }
    }
    //System.out.println(result);
    return result;
}

public static ArrayList paserxmlbynode(String passxmlstr,String bignode)
{
     Document xmlDoc=null;
     
     try {
            ByteArrayInputStream bis = new ByteArrayInputStream(passxmlstr.getBytes("UTF-8"));
            xmlDoc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(bis);
        } catch (Throwable e) {
            try {
                throw new Exception("MSG_COULDN'T_PARSE_XML", e);
            } catch (Exception e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
        }
        
         //   System.out.print(passxmlstr);
        ArrayList<Map> listitem=new ArrayList<Map>();   
        
        // find bignode
        NodeList nlds=xmlDoc.getElementsByTagName(bignode);
        int size =nlds.getLength();
        for(int j=0;j<size;j++)
        {
            Node nd=nlds.item(j).getFirstChild().getNextSibling();
            Map<String,String> map=new HashMap<String,String>();
            while(nd!=null)
            {
                map.put(nd.getNodeName(), nd.getFirstChild().getNodeValue());
                nd= nd.getNextSibling().getNextSibling();
            }
            listitem.add(map);
        }
      
       // System.out.print(listitem.size());
     return listitem;
}
   

附：从文件读取xml文件

    public String getStringofxmlfromdisk()
    {
        String passxmlstr = "";
        String filepath="D:\\test\\rxml.xml";
 
        BufferedReader reader = null;
        try {
            reader = new BufferedReader(new FileReader(new File(filepath)));
            String tempString = null;
            int line = 1;
            while ((tempString = reader.readLine()) != null) {
                passxmlstr += tempString;
                line++;
            }
            // System.out.println("  " + passxmlstr);
            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException e1) {
                }
            }
        }
        return passxmlstr;
    }