package book.rssreader;

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

public class DbManager {
		//類成員Connection
		protected static Connection conn;
	    //mysql的驅(qū)動類，定義為常量
		public static final String CLASS_NAME = "com.mysql.jdbc.Driver";
	    //數(shù)據(jù)庫的連接地址，定義為常量
		public static final String CONNET_STR = "jdbc:mysql://localhost/rssreader";
	    //獲得Connetion
		public static Connection getConnection() {
			try {
				Class.forName(CLASS_NAME);//使用類反射加載該驅(qū)動類
				//獲得一個Connection
				conn = DriverManager.getConnection(CONNET_STR, "root", "");
				return conn;//返回該Connection
			} catch (Exception e) {
				e.printStackTrace();
				return null;
			}
		}
		//傳入查詢數(shù)據(jù)庫的sql語句，返回ResultSet
		public static ResultSet getResultSet(String sql) {
			boolean bSuccess = true;
			Statement stmt = null;//聲明Statement stmt
			ResultSet rs = null;//聲明ResultSet rs
			Connection con = getConnection();//調(diào)用getConnetion()方法獲得一個Connetion
			if (con == null)//如果Connection 為null則返回假
				bSuccess = false;
			if (bSuccess) {
				try {		
					stmt = con.createStatement();//通過Connection創(chuàng)建一個Statemet
					rs = stmt.executeQuery(sql);//執(zhí)行查詢語句，
				} catch (SQLException e) {
					e.printStackTrace();
					bSuccess = false;
				}
			}
			if (bSuccess)//如果執(zhí)行成功，則返回rs
				return rs;
			else
				return null;
		}
	   //傳入執(zhí)行數(shù)據(jù)更新的語句，返回更新結(jié)果，真為成功執(zhí)行
		public static boolean excute(String sql) {
			boolean bSuccess = true;
			Statement stmt = null;//聲明Statement stmt
			Connection con = getConnection();//調(diào)用getConnetion()方法獲得一個Connetion
			if (con == null)//如果Connection 為null則返回假
				bSuccess = false;
			if (bSuccess) {
				try {
					stmt = con.createStatement();//通過Connection創(chuàng)建一個Statemet
					bSuccess = stmt.execute(sql);//執(zhí)行更新數(shù)據(jù)操作
				} catch (SQLException e) {
					e.printStackTrace();
					bSuccess = false;
				}
			}
			return bSuccess;
		}
	    //釋放Connection
		public static void releaseConnection() {
			try {
				if (conn != null)//  如果Connetion 不為null則關(guān)閉Connection
					conn.close();
			} catch (SQLException e) {
				e.printStackTrace();
			}
		}

}