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;
    }