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）：

 1 public static void main(String[] args)
 2     {        //"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);

 5     //得到的结果是“Right”

 6 

 7
 8     }
 9
10 /**
11  * common method "findbynode" get target from Xml 2
12  *
13  * @param args example:
14  *
15  * {
16  * <field>     //field-->bignode
17  *    <name>Motor hand</name> //name-->clum1 , "Motor hand"-->itemvalue
18  *    <value>Right</value>    //value-->clum2
19  *    <type>Dotted</type>
20  * </field>
21  *  }
22  *
23  */
24 public static String  findbynode(String passxmlstr,String bignode,String clum1,String itemvalue,String clum2)
25 {
26     String result="";
27
28     /*
29     bignode="field";
30     clum1="name";
31     clum2="value";
32     */
33
34     ArrayList<Map> al=paserxmlbynode(passxmlstr,bignode);
35     for(Map m : al)
36     {
37          if(m.get(clum1).toString().equals(itemvalue))
38          {
39              result=m.get(clum2).toString();
40              break;
41          }
42     }
43     //System.out.println(result);
44     return result;
45 }
46
47 public static ArrayList paserxmlbynode(String passxmlstr,String bignode)
48 {
49      Document xmlDoc=null;
50
51      try {
52             ByteArrayInputStream bis = new ByteArrayInputStream(passxmlstr.getBytes("UTF-8"));
53             xmlDoc = DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(bis);
54         } catch (Throwable e) {
55             try {
56                 throw new Exception("MSG_COULDN‘T_PARSE_XML", e);
57             } catch (Exception e1) {
58                 // TODO Auto-generated catch block
59                 e1.printStackTrace();
60             }
61         }
62
63          //   System.out.print(passxmlstr);
64         ArrayList<Map> listitem=new ArrayList<Map>();
65
66         // find bignode
67         NodeList nlds=xmlDoc.getElementsByTagName(bignode);
68         int size =nlds.getLength();
69         for(int j=0;j<size;j++)
70         {
71             Node nd=nlds.item(j).getFirstChild().getNextSibling();
72             Map<String,String> map=new HashMap<String,String>();
73             while(nd!=null)
74             {
75                 map.put(nd.getNodeName(), nd.getFirstChild().getNodeValue());
76                 nd= nd.getNextSibling().getNextSibling();
77             }
78             listitem.add(map);
79         }
80
81        // System.out.print(listitem.size());
82      return listitem;
83 }
84    

附：从文件读取xml文件

 1     public String getStringofxmlfromdisk()
 2     {
 3         String passxmlstr = "";
 4         String filepath="D:\\test\\rxml.xml";
 5
 6         BufferedReader reader = null;
 7         try {
 8             reader = new BufferedReader(new FileReader(new File(filepath)));
 9             String tempString = null;
10             int line = 1;
11             while ((tempString = reader.readLine()) != null) {
12                 passxmlstr += tempString;
13                 line++;
14             }
15             // System.out.println("  " + passxmlstr);
16             reader.close();
17         } catch (IOException e) {
18             e.printStackTrace();
19         } finally {
20             if (reader != null) {
21                 try {
22                     reader.close();
23                 } catch (IOException e1) {
24                 }
25             }
26         }
27         return passxmlstr;
28     }

java中dom解析xml