昨天寫的UserDao - Figol‘s Blog

figol 2006-02-19

展開全文

//UserBean.java

package net.z1w.DAO;
import net.z1w.DAO.*;
/**
*UserBean
**/
class UserBean{
private int ID;
private String name;
private String password;
/**
*構(gòu)造方法
**/
public UserBean(){

}

public void setID(int ID){
  this.ID=ID;
}
public int getID(){
  return ID;
}
public void setName(String name){
  this.name=name;
}
public String getName(){
  return name;
}
public void setPassword(String password){
  this.password=password;
}
public String getPassword(){
  return password;
}

public String toString(){
  return "ID:"+ID+" name:"+name+" password:"+password;
}
}

//UserDAO.java

package net.z1w.DAO;
import java.sql.*;
import java.util.*;
import net.z1w.DAO.*;
/**
*UserDAO接口，定義了User的數(shù)據(jù)庫操作
**/
public interface UserDAO{
/**
*添加用戶
   * @return either (1) the row count for INSERT, UPDATE,
   * or DELETE statements or (2) 0 for SQL statements
   * that return nothing
**/
public int addUser() throws SQLException;
/**
*修改用戶
   * @return either (1) the row count for INSERT, UPDATE,
   * or DELETE statements or (2) 0 for SQL statements
   * that return nothing
**/
public int updateUser() throws SQLException;
/**
*刪除用戶
   * @return either (1) the row count for INSERT, UPDATE,
   * or DELETE statements or (2) 0 for SQL statements
   * that return nothing
**/
public int deleteUser() throws SQLException;
/**
*查詢用戶
*@return 返回查詢得到的User
**/
public UserBean searchUser() throws SQLException;
/**
*查詢所有用戶
* @return 返回List類型，其中存放著所有用戶
**/
public List searchAllUser() throws SQLException;
/**
*刪除所有用戶
   * @return either (1) the row count for INSERT, UPDATE,
   * or DELETE statements or (2) 0 for SQL statements
   * that return nothing
**/
public int deleteAllUser() throws SQLException;

}

//UserDAOOperate.java

package net.z1w.DAO;
import java.sql.*;
import java.util.*;
import net.z1w.DAO.*;
/**
*UserDAO的實現(xiàn)類
**/
public class UserDAOOperate implements UserDAO{
  /**
   *用戶Bean
   **/
  private UserBean user;
  /**
   *構(gòu)造方法
   * @param user UserBean類型，表示一個用戶
   **/
  public UserDAOOperate(UserBean user){
   this.user=user;
  }
  /**
   *添加一個用戶
   * @return either (1) the row count for INSERT, UPDATE,
   * or DELETE statements or (2) 0 for SQL statements
   * that return nothing
   **/
  public int addUser() throws SQLException{
   int result=0;
   String sql="insert into Users values(?,?,?)";
   Connection conn=ConnectionPool.getConnection();
   PreparedStatement stat=conn.prepareStatement(sql);
   stat.setInt(1,user.getID());
   stat.setString(2,user.getName());
   stat.setString(3,user.getPassword());
   result=stat.executeUpdate();
   stat.close();
   conn.close();
   return result;
  }
  /**
   *修改用戶
   **/
  public int updateUser() throws SQLException{
   int result=0;
   Connection conn=ConnectionPool.getConnection();
   String sql="update Users set ID=?,name=?,password=? where ID=?";
   PreparedStatement stat=conn.prepareStatement(sql);
   stat.setInt(1,user.getID());
   stat.setString(2,user.getName());
   stat.setString(3,user.getPassword());
   stat.setInt(4,user.getID());
   result=stat.executeUpdate();
   stat.close();
   conn.close();
   return result;
  }
  /**
   *刪除用戶
   **/
  public int deleteUser() throws SQLException{
   int result=0;
   Connection conn=ConnectionPool.getConnection();
   String sql="delete from Users where ID=?";
   PreparedStatement stat=conn.prepareStatement(sql);
   stat.setInt(1,user.getID());
   result=stat.executeUpdate();
   stat.close();
   conn.close();
   return result;
  }
  /**
   *查詢用戶
   * @return 返回查詢得到的User對象
   **/
  public UserBean searchUser() throws SQLException{
   UserBean userRes=new UserBean();
   Connection conn=ConnectionPool.getConnection();
   String sql="select ID,name,password from users where ID=?";
   PreparedStatement stat=conn.prepareStatement(sql);
   stat.setInt(1,user.getID());
   ResultSet res=stat.executeQuery();
   if(res.next()){
  userRes.setID(res.getInt("ID"));
  userRes.setName(res.getString("name"));
  userRes.setPassword(res.getString("password"));
   }else{
    userRes=null;
   }
   res.close();
   stat.close();
   conn.close();
   return userRes;
  }
  /**
   *查詢所有用戶
   * @return 返回List類型，其中存放著查詢到的用戶
   **/
  public List searchAllUser() throws SQLException{
   List result=new ArrayList();

   Connection conn=ConnectionPool.getConnection();
   String sql="select * from users";
   Statement stat=conn.createStatement();
   ResultSet res=stat.executeQuery(sql);
   while(res.next()){
    UserBean userRes=new UserBean();
    userRes.setID(res.getInt("ID"));
    userRes.setName(res.getString("name"));
    userRes.setPassword(res.getString("password"));
    result.add(userRes);
   }
   res.close();
   stat.close();
   conn.close();
   return result;
  }
  /**
*刪除所有用戶
   * @return either (1) the row count for INSERT, UPDATE,
   * or DELETE statements or (2) 0 for SQL statements
   * that return nothing
**/
public int deleteAllUser() throws SQLException{
  int result=0;
  Connection conn=ConnectionPool.getConnection();
  Statement stat=conn.createStatement();
  String sql="delete from users";
  result=stat.executeUpdate(sql);
  stat.close();
  conn.close();
  return result;
}
}

//DAOFactory.java

package net.z1w.DAO;
import java.sql.*;
import net.z1w.DAO.*;
/**
*DAOFactory
**/
public class DAOFactory{
  private DAOFactory(){
  }
  /**
   * UserDAO工廠方法
   * @param user UserBean類型，代表一個用戶
   * @return 返回UserDAO接口
   **/
  public static UserDAO getUserDAO(UserBean user){
   return new UserDAOOperate(user);
  }

}

//ConnectionPool.java

package net.z1w.DAO;
import java.sql.*;
/**
*連接池類
**/
public class ConnectionPool{
/**
* 連接池中獲得一個空閑連接
* @return 返回Connection類型連接對象
**/
public static Connection getConnection() throws SQLException{
  try{
   Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
  }catch(ClassNotFoundException classE){
   System.out.println("驅(qū)動程序加載失敗");
   classE.printStackTrace();
  }

  String odbcSourceName="BlogDB";
  String url="jdbc:odbc:"+odbcSourceName;
  String user="";
  String password="";
  Connection conn=DriverManager.getConnection(url,user,password);
  return conn;
}
}

//TestDAO.java

package net.z1w.DAO;
import java.util.*;
import java.sql.*;
import net.z1w.DAO.*;
/**
*測試DAO
**/
public class TestDAO{
public static void main(String[] args){
  UserBean user=new UserBean();
  user.setID(1);
  user.setName("ZhangSan");
  user.setPassword("123456");
  try{
   UserDAO dao=DAOFactory.getUserDAO(user);
   for(int i=0;i<10;i++){
    dao.addUser();
    System.out.println("添加了一個用戶:"+user);
    user.setID(i+2);
    user.setName("Zhang"+i*987/34);
    user.setPassword("#$^"+i*i*3+"sdf$%");
   }

   dao.deleteUser();
   System.out.println("刪除了一個用戶:"+user);
   dao.addUser();
   System.out.println("添加一個用戶:"+user);
   user.setName("LiSi");
   dao.updateUser();
   System.out.println("修改了一個用戶:"+user);
   System.out.println("將要查詢ID=5的用戶.");
   user.setID(5);
   UserBean newUser=dao.searchUser();
   System.out.println("查詢到了一個用戶:"+newUser);
   List list=dao.searchAllUser();
   System.out.println("查詢所有用戶信息，如下：");
   Iterator i=list.iterator();
   while(i.hasNext()){

    System.out.println(i.next());
   }
   dao.deleteAllUser();
   System.out.println("刪除所有用戶成功。Over~~~!");

  }catch(SQLException sqlE){
   System.out.println("SQL語句出錯");
   sqlE.printStackTrace();
  }
}
}
呵呵，昨天用了一下午寫的。DAO的全稱是數(shù)據(jù)訪問對象，通過DAO可以封裝數(shù)據(jù)庫的底層操作，使開發(fā)人員不必關(guān)心對象向表關(guān)系的轉(zhuǎn)換，專心于業(yè)務(wù)邏輯的開發(fā)。DAO屬于持久層，具體詳細的內(nèi)容我就不介紹了，大家可以去查一些相關(guān)的資料，網(wǎng)上有很多。