使用java自带的xml解析器解析xml

  1 //------------------ main point ---------------------    
  2 javax.xml.parsers.SAXParserFactory
  3 public static void main(String[] args)
  4     {   
  5  //cdu 存放结果的对象        
  6  CS3drawUnit cdu=new CS3drawUnit();
  7  
  8  SAXParserFactory factory = SAXParserFactory.newInstance();
  9  
 10   SAXParser parser;
 11                 try {
 12                     parser = factory.newSAXParser();
 13                     
 14                     /* // 方式一
 15                     InputStream is=new ByteArrayInputStream(strxml.getBytes("UTF-8"));
 16                     parser.parse(is, new Apphandler(cdu));
 17                     */
 18                     
 19                     // 方式二
 20                     parser.parse(new File("cs3.xml"),new Apphandler(cdu));
 21                     }
 22                     catch (ParserConfigurationException e) {
 23                         // TODO Auto-generated catch block
 24                         e.printStackTrace();
 25                     } catch (SAXException e) {
 26                         // TODO Auto-generated catch block
 27                         e.printStackTrace();
 28                     } catch (IOException e) {
 29                         // TODO Auto-generated catch block
 30                         e.printStackTrace();
 31                     }
 32     }    
 33     
 34 // 存放结果的实体    
 35 //------------------CS3drawUnit bean---------------------    
 36 public class CS3drawUnit {
 37 
 38     //可以有多个 fields，因为太多我省略了好多
 39     private String XWallThickness="";
 40     
 41     public String getXWallThickness() {
 42         return XWallThickness;
 43     }
 44     public void setXWallThickness(String xWallThickness) {
 45         XWallThickness = xWallThickness;
 46     }
 47     
 48 }
 49 
 50 // 这就是处理类handler
 51 //------------------Apphandler ---------------------    
 52 import org.xml.sax.Attributes;
 53 import org.xml.sax.SAXException;
 54 import org.xml.sax.helpers.DefaultHandler;
 55 
 56 public class Apphandler extends DefaultHandler {
 57 
 58     /*
 59     <field>
 60     <name>Type / tubes in face</name>
 61     <value>A (1/2" OD) / 16</value>
 62     </field>
 63     
 64     */
 65     
 66     
 67     Unit u=null;
 68     //内部类 为了在characters方法中调用，使代码显的清晰
 69     public class Unit{
 70         
 71         private String xname="";
 72         private String xvalue="";
 73         private String xmodelNo ="";  
 74         private String xahTag ="";  
 75         
 76         
 77         public String getXahTag() {
 78             return xahTag;
 79         }
 80         public void setXahTag(String xahTag) {
 81             this.xahTag = xahTag;
 82         }
 83         public String getXname() {
 84             return xname;
 85         }
 86         public void setXname(String xname) {
 87             this.xname = xname;
 88         }
 89         public String getXvalue() {
 90             return xvalue;
 91         }
 92         public void setXvalue(String xvalue) {
 93             this.xvalue = xvalue;
 94         }
 95         public String getxmodelNo() {
 96             return xmodelNo;
 97         }
 98         public void setxmodelNo(String xmodelNo) {
 99             this.xmodelNo = xmodelNo;
100         }
101         
102         
103     }
104     CS3drawUnit cdu=null;
105     
106     private final int xname_STATE = 1;  
107     private final int xvalue_STATE = 2;  
108     private final int xmodelNo_STATE = 3; 
109     private final int xahTag_STATE = 4;
110         
111 
112    private int currentState;  
113     
114    public  Apphandler(CS3drawUnit cdu)
115    {
116        this.cdu=cdu;
117        currentState=0;
118        u=new Unit();
119    }
120     
121      //获取解析结果，可以再处理，此处把结果再加工，set到cdu实例中返回
122     ///@Override
123     public void endElement(String uri, String localName, String qName)
124             throws SAXException {
125          
126           
127           if(qName.equals("modelNo")&& u!= null){
128               cdu.setXModelNo(u.getxmodelNo());
129           }  
130           if(qName.equals("ahTag")&& u!= null){          
131               cdu.setXAhTag(u.getXahTag());
132           }
133          
134     }
135 
136     public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
137         // TODO Auto-generated method stub
138         //System.out.println("qName:"+qName);
139             if (qName.equals("field")){  
140                  u=new Unit();  
141                  return;  
142             }  
143               
144             if (qName.equals("name")){  
145                 currentState = xname_STATE;  
146                 return ;  
147             } 
148             
149             if (qName.equals("value")){  
150                 currentState = xvalue_STATE;  
151                 return ;  
152             }
153             if (qName.equals("modelNo")){  
154                 currentState = xmodelNo_STATE;  
155                 return ;  
156             }
157             
158             if (qName.equals("ahTag")){  
159                 currentState = xahTag_STATE;  
160                 return ;  
161             }
162     }
163     
164     
165     public void characters(char[] ch, int start, int length) throws SAXException {
166         
167         //length这个值在某些情况下，会被裁断（莫名其妙），估计是bug，遇到过一回，
168         //所以我在后来不让它解析出错时的字段，改用Dom解析。
169         String theString = new String(ch, start, length); 
170        
171         switch(currentState)
172         {
173             case xname_STATE:  
174                 u.setXname(theString);                
175                 currentState = 0;  
176                 break;  
177                   
178             case xvalue_STATE:  
179                 u.setXvalue(theString);                
180                 currentState = 0;  
181                 break;  
182             case xmodelNo_STATE:  
183                 u.setxmodelNo(theString);                
184                 currentState = 0;  
185                 break;
186             case xahTag_STATE:  
187                 u.setXahTag(theString);                
188                 currentState = 0;  
189                 break;     
190         }         
191     }
192 
193 }