dom4j 读大xml文件

今天由于项目需要，读取一个几百兆的xml文件，直接内存溢出了，主要原因是我一次性读取xml文件的内容造成的，对于大的xml文件还是要读取部分到内存，然后从内存删除，再读取，这里用了dom4j的saxreader

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1. package test;  
2.   
3. import java.io.File;  
4. import java.io.FileInputStream;  
5. import java.io.InputStream;  
6. import java.sql.Connection;  
7. import java.sql.DriverManager;  
8. import java.sql.PreparedStatement;  
9. import java.sql.SQLException;  
10. import java.text.DateFormat;  
11. import java.text.SimpleDateFormat;  
12. import java.util.Date;  
13.   
14. import org.apache.commons.codec.binary.Base64;  
15. import org.dom4j.Element;  
16. import org.dom4j.ElementHandler;  
17. import org.dom4j.ElementPath;  
18. import org.dom4j.io.SAXReader;  
19.   
20. public class MySaxHandler implements ElementHandler {  
21.       
22.     SAXReader reader;  
23.       
24.     static String jdbcURL = "jdbc:sybase:Tds:172.25.130.1:4100/center?charset=cp936";  
25.     static String jdbcDriver = "com.sybase.jdbc3.jdbc.SybDriver";  
26.     static String userName = "xxx";  
27.     static String password = "xxx";  
28.       
29.     ThreeYearBlackEnt threeYearBlackEnt = new ThreeYearBlackEnt();  
30.     public static Connection con = null;  
31.       
32.     public static Connection getConnection() throws Exception {  
33.         Class.forName(jdbcDriver);  
34.         return DriverManager.getConnection(jdbcURL, userName, password);  
35.     }  
36.     public static java.sql.Date stringToDate(String str) {  
37.         DateFormat format = new SimpleDateFormat("yyyy-MM-dd");  
38.         Date date = null;  
39.         try {  
40.             // Fri Feb 24 00:00:00 CST 2012  
41.             date = format.parse(str);  
42.         } catch (Exception e) {  
43.             e.printStackTrace();  
44.         }  
45.         // 2012-02-24  
46.         //date = java.sql.Date.valueOf(str);  
47.                                                
48.         return java.sql.Date.valueOf(str);  
49.     }  
50.     public static void addDataBackEnt(Connection con,ThreeYearBlackEnt threeYearBlackEnt) throws SQLException{  
51.         String sql = "insert into J_QYDXB_QG    (QYMC, ZCH,REGORG, FDDBR,FDDBR_ZJHM,FDDBR_ZJMC,DXRQ,BZSM)   values(?, ?, ?, ?, ?,?,?,?)";  
52.         PreparedStatement pst = con.prepareStatement(sql);  
53.           
54.         pst.setString(1, threeYearBlackEnt.ENTNAME);  
55.         pst.setString(2, threeYearBlackEnt.REGNO);  
56.         pst.setString(3, threeYearBlackEnt.REGORG);  
57.         pst.setString(4, threeYearBlackEnt.NAME);  
58.         pst.setString(5, threeYearBlackEnt.CERNO);  
59.         pst.setString(6, threeYearBlackEnt.CERTYPE);  
60.         pst.setDate(7,  stringToDate(threeYearBlackEnt.REVDATE));  
61.         pst.setString(8, threeYearBlackEnt.ILLEGACT);  
62.           
63.         pst.execute();  
64.         pst.close();  
65.     }  
66.       
67.     public MySaxHandler() {  
68.         // test.xml文件跟类放在同一目录下  
69.         try {  
70.             con = getConnection();  
71.             InputStream is = MySaxHandler.class.getResourceAsStream("threeYearBlackEnt_data.xml");   
72.             //InputStream is = new FileInputStream("D:\\programfiles\\workspace\\Counter\\threeYearBlackEnt_data1.xml");  
73.             reader = new SAXReader();  
74.             reader.setDefaultHandler(this);  
75.             reader.read(is);  
76.         } catch (Exception e) {  
77.             e.printStackTrace();  
78.         }  
79.     }  
80.     public void onEnd(ElementPath ep) {  
81.         Element element = ep.getCurrent(); //获得当前节点  
82.         if(element.getName().equals("ENTNAME")) {  
83.             threeYearBlackEnt.ENTNAME = new String(Base64.decodeBase64(element.getText()));  
84.             p("ENTNAME="+ threeYearBlackEnt.ENTNAME );  
85.               
86.         }else if(element.getName().equals("REGNO")) {  
87.             threeYearBlackEnt.REGNO = new String(Base64.decodeBase64(element.getText()));  
88.             p("REGNO="+ threeYearBlackEnt.REGNO);  
89.               
90.         }else if(element.getName().equals("REGORG")) {  
91.             threeYearBlackEnt.REGORG = new String(Base64.decodeBase64(element.getText()));  
92.             p("REGORG="+ threeYearBlackEnt.REGORG);  
93.         }else if(element.equals("NAME")) {  
94.             threeYearBlackEnt.NAME = new String(Base64.decodeBase64(element.getText()));  
95.             p("NAME="+ threeYearBlackEnt.NAME);  
96.         }else if(element.getClass().equals("CERNO")) {  
97.             threeYearBlackEnt.CERNO = new String(Base64.decodeBase64(element.getText()));  
98.             p("CERNO="+ threeYearBlackEnt.CERNO);  
99.               
100.         }else if(element.getName().equals("CERTYPE")){  
101.             threeYearBlackEnt.CERTYPE = new String(Base64.decodeBase64(element.getText()));  
102.             p("CERTYPE="+ threeYearBlackEnt.CERTYPE);  
103.               
104.         }else if(element.getName().equals("REVDATE")) {  
105.             threeYearBlackEnt.REVDATE = new String(Base64.decodeBase64(element.getText()));  
106.             p("REVDATE="+ threeYearBlackEnt.REVDATE);  
107.               
108.         }else if(element.getName().equals("ILLEGACT")) {  
109.             threeYearBlackEnt.ILLEGACT =new String(Base64.decodeBase64(element.getText()));  
110.             p("ILLEGACT="+ threeYearBlackEnt.ILLEGACT);  
111.               
112.             try {  
113.                 addDataBackEnt(con, threeYearBlackEnt);  
114.             } catch (SQLException e) {  
115.                 // TODO Auto-generated catch block  
116.                 e.printStackTrace();  
117.             }  
118.         }  
119.           
120.           
121.           
122.         element.detach(); //记得从内存中移去  
123.     }  
124.   
125.     public void onStart(ElementPath ep) {  
126.     }  
127.       
128.     public static void main(String[] args){  
129.         new MySaxHandler();  
130.     }  
131.       
132.     public static void p(Object o) {  
133.         if(o != null) System.out.println(o.toString());  
134.     }  
135.   
136. }