//UserBean.java
package net.z1w.DAO;
import net.z1w.DAO.*;
/**
*UserBean
**/
class UserBean{
private int ID;
private String name;
private String password;
/**
*構造方法
**/
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的數據庫操作
**/
public interface UserDAO{
/**
*添加用戶(hù)
* @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(hù)
* @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(hù)
* @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(xún)用戶(hù)
*@return 返回查詢(xún)得到的User
**/
public UserBean searchUser() throws SQLException;
/**
*查詢(xún)所有用戶(hù)
* @return 返回List類(lèi)型，其中存放著(zhù)所有用戶(hù)
**/
public List searchAllUser() throws SQLException;
/**
*刪除所有用戶(hù)
* @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(shí)現類(lèi)
**/
public class UserDAOOperate implements UserDAO{
/**
*用戶(hù)Bean
**/
private UserBean user;
/**
*構造方法
* @param user UserBean類(lèi)型，表示一個(gè)用戶(hù)
**/
public UserDAOOperate(UserBean user){
this.user=user;
}
/**
*添加一個(gè)用戶(hù)
* @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(hù)
**/
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(hù)
**/
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(xún)用戶(hù)
* @return 返回查詢(xún)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(xún)所有用戶(hù)
* @return 返回List類(lèi)型，其中存放著(zhù)查詢(xún)到的用戶(hù)
**/
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(hù)
* @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(chǎng)方法
* @param user UserBean類(lèi)型，代表一個(gè)用戶(hù)
* @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(lèi)
**/
public class ConnectionPool{
/**
* 連接池中獲得一個(gè)空閑連接
* @return 返回Connection類(lèi)型連接對象
**/
public static Connection getConnection() throws SQLException{
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
}catch(ClassNotFoundException classE){
System.out.println("驅動(dòng)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(gè)用戶(hù):"+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(gè)用戶(hù):"+user);
dao.addUser();
System.out.println("添加一個(gè)用戶(hù):"+user);
user.setName("LiSi");
dao.updateUser();
System.out.println("修改了一個(gè)用戶(hù):"+user);
System.out.println("將要查詢(xún)ID=5的用戶(hù).");
user.setID(5);
UserBean newUser=dao.searchUser();
System.out.println("查詢(xún)到了一個(gè)用戶(hù):"+newUser);
List list=dao.searchAllUser();
System.out.println("查詢(xún)所有用戶(hù)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(hù)成功。Over~~~!");
}catch(SQLException sqlE){
System.out.println("SQL語(yǔ)句出錯");
sqlE.printStackTrace();
}
}
}
呵呵，昨天用了一下午寫(xiě)的。DAO的全稱(chēng)是數據訪(fǎng)問(wèn)對象，通過(guò)DAO可以封裝數據庫的底層操作，使開(kāi)發(fā)人員不必關(guān)心對象向表關(guān)系的轉換，專(zhuān)心于業(yè)務(wù)邏輯的開(kāi)發(fā)。DAO屬于持久層，具體詳細的內容我就不介紹了，大家可以去查一些相關(guān)的資料，網(wǎng)上有很多。
當然DAO只是數據訪(fǎng)問(wèn)模式的一種，還有DTO，微軟的ADO等等，還有Hibernate呵呵。。。DAO適合做一些小型或中型的系統。
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