Java生成XML文件

我们在数据库中的数据可以将其提取出来生成XML文件，方便传输。例如数据库中有Admin这张表:



我们写一个java类表示admin数据:

1 package xmlDom.vo;
2
3 import java.io.Serializable;
4 import java.util.Date;
5 import java.util.List;
6
7 public class Admin implements Serializable
8 {
9     private String aid;
10     private String password;
11     private Integer rid;
12     private Integer type;
13     private Date lastdate;
14     private Integer flag ;
15
16
17
18
19     public Integer getRid()
20     {
21         return rid;
22     }
23     public void setRid(Integer rid)
24     {
25         this.rid = rid;
26     }
27     public String getAid()
28     {
29         return aid;
30     }
31     public void setAid(String aid)
32     {
33         this.aid = aid;
34     }
35     public String getPassword()
36     {
37         return password;
38     }
39     public void setPassword(String password)
40     {
41         this.password = password;
42     }
43     public Integer getType()
44     {
45         return type;
46     }
47     public void setType(Integer type)
48     {
49         this.type = type;
50     }
51     public Date getLastdate()
52     {
53         return lastdate;
54     }
55     public void setLastdate(Date lastdate)
56     {
57         this.lastdate = lastdate;
58     }
59     public Integer getFlag()
60     {
61         return flag;
62     }
63     public void setFlag(Integer flag)
64     {
65         this.flag = flag;
66     }
67
68 }

然后通过JDBC 将表中的数据转换成一个链表:

1 package xmlDom.dbc;
2
3 import java.sql.Connection;
4 import java.sql.DriverManager;
5 import java.sql.SQLException;
6
7 public class DatabaseConnection
8 {
9     private static final String MYSQLDRIVER = "org.gjt.mm.mysql.Driver";
10     private static final String MYSQLURL = "jdbc:mysql://localhost:3306/hrdb";
11     private static final String USERNAME = "root";
12     private static final String PASSWORD = "admin";
13
14     private Connection conn;
15
16     public DatabaseConnection()
17     {
18         try
19         {
20             Class.forName(MYSQLDRIVER);
21             this.conn = DriverManager.getConnection(MYSQLURL, USERNAME, PASSWORD);
22         } catch (Exception e)
23         {
24             e.printStackTrace();
25         }
26     }
27
28     public Connection getConnection() throws Exception
29     {
30         if (null != this.conn)
31             return this.conn;
32         else
33             throw new Exception("获取数据库连接失败");
34     }
35
36     public void close()
37     {
38         if (null != this.conn)
39         {
40             try
41             {
42                 this.conn.close();
43             } catch (SQLException e)
44             {
45                 e.printStackTrace();
46             }
47         }
48     }
49 }

public static List<Admin> loadFromDB() throws Exception
{
List<Admin> allAdmins = new ArrayList<Admin>();

DatabaseConnection dbc = new DatabaseConnection();
Connection conn = dbc.getConnection();
PreparedStatement ps = conn.prepareStatement("SELECT aid,rid,type,lastdate,flag FROM admin");
ResultSet rs = ps.executeQuery();
while(rs.next())
{
Admin vo = new Admin();

vo.setAid(rs.getString("aid"));
vo.setRid(rs.getInt("rid"));
vo.setType(rs.getInt("type"));
vo.setLastdate(rs.getDate("lastdate"));
vo.setFlag(rs.getInt("flag"));

allAdmins.add(vo);
}

return allAdmins;
}

然后将该链表转换成内存中的XML结构:

public static Document getDocument( List<Admin> allAdmins) throws Exception
{
DocumentBuilderFactory dbfactory = DocumentBuilderFactory.newInstance();
DocumentBuilder documentBuilder = dbfactory.newDocumentBuilder();
Document document = documentBuilder.newDocument();

Element root = document.createElement("admins");

for(Admin item : allAdmins)
{
Element admin = document.createElement("admin");
admin.setAttribute("aid", item.getAid());

Element rid = document.createElement("rid");
rid.appendChild(document.createTextNode(String.valueOf(item.getRid())));

Element type = document.createElement("type");
type.appendChild(document.createTextNode(String.valueOf(item.getType())));

Element lastdate = document.createElement("lastdate");
lastdate.appendChild(document.createTextNode(String.valueOf(item.getLastdate())));

Element flag = document.createElement("flag");
flag.appendChild(document.createTextNode(String.valueOf(item.getFlag())));

admin.appendChild(rid);
admin.appendChild(type);
admin.appendChild(lastdate);
admin.appendChild(flag);

root.appendChild(admin);
}

document.appendChild(root);

return document;
}

然后将该内存的XML保存到本地中:

public static void main(String[] args) throws Exception
{
List<Admin> allAdmins  = loadFromDB();
Document document = getDocument(allAdmins);

Source source = new DOMSource(document);
StreamResult stream = new StreamResult(new FileOutputStream(new File("C:\\D\\code\\resource\\admins.xml")));
TransformerFactory transFactory = TransformerFactory.newInstance();
Transformer trans = transFactory.newTransformer();
trans.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
trans.transform(source, stream);

System.out.println("main done//~~");
}

也可以用下面代码把xml文件加载到内存中:

1     public static Document loadFromFile(String path) throws Exception
2     {
3         Document document = null;
4         DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
5         DocumentBuilder builder = factory.newDocumentBuilder();
6         document = builder.parse(new File(path));
7         return document;
8     }