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:

 package xmlDom.vo;

 import java.io.Serializable;
 import java.util.Date;
 import java.util.List;

 public class Admin implements Serializable
 {
     private String aid;
     private String password;
     private Integer rid;
     private Integer type;
     private Date lastdate;
     private Integer flag ; 

     public Integer getRid()
     {
         return rid;
     }
     public void setRid(Integer rid)
     {
         this.rid = rid;
     }
     public String getAid()
     {
         return aid;
     }
     public void setAid(String aid)
     {
         this.aid = aid;
     }
     public String getPassword()
     {
         return password;
     }
     public void setPassword(String password)
     {
         this.password = password;
     }
     public Integer getType()
     {
         return type;
     }
     public void setType(Integer type)
     {
         this.type = type;
     }
     public Date getLastdate()
     {
         return lastdate;
     }
     public void setLastdate(Date lastdate)
     {
         this.lastdate = lastdate;
     }
     public Integer getFlag()
     {
         return flag;
     }
     public void setFlag(Integer flag)
     {
         this.flag = flag;
     } 

 }

然后通过JDBC 将表中的数据转换成一个链表:

 package xmlDom.dbc;

 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;

 public class DatabaseConnection
 {
     private static final String MYSQLDRIVER = "org.gjt.mm.mysql.Driver";
     private static final String MYSQLURL = "jdbc:mysql://localhost:3306/hrdb";
     private static final String USERNAME = "root";
     private static final String PASSWORD = "admin";

     private Connection conn;

     public DatabaseConnection()
     {
         try
         {
             Class.forName(MYSQLDRIVER);
             this.conn = DriverManager.getConnection(MYSQLURL, USERNAME, PASSWORD);
         } catch (Exception e)
         {
             e.printStackTrace();
         }
     }

     public Connection getConnection() throws Exception
     {
         if (null != this.conn)
             return this.conn;
         else
             throw new Exception("获取数据库连接失败");
     }

     public void close()
     {
         if (null != this.conn)
         {
             try
             {
                 this.conn.close();
             } catch (SQLException e)
             {
                 e.printStackTrace();
             }
         }
     }
 }

    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:

     public static Document loadFromFile(String path) throws Exception
     {
         Document document = null;
         DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
         DocumentBuilder builder = factory.newDocumentBuilder();
         document = builder.parse(new File(path));
         return document;
     }