connectmanager.java

学生成绩管理系统 eclipse rcp开发 swt技术

package com.zdh.sms.db;

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

import org.eclipse.jface.preference.IPreferenceStore;

import com.zdh.sms.Activator;
import com.zdh.sms.preferences.DBPreferencePage;



public class ConnectManager {
	private static Connection con;

	private ConnectManager() {
	}

	public static Connection getConnection() throws SQLException {
		if (con != null && !con.isClosed())// 不为空且没关闭
			return con;
		// 由首选项的设置获得连接
		IPreferenceStore ps = Activator.getDefault().getPreferenceStore();
		String className = ps.getString(DBPreferencePage.CLASSNAME_KEY);
		String url = ps.getString(DBPreferencePage.URL_KEY);
		String username = ps.getString(DBPreferencePage.USERNAME_KEY);
		String password = ps.getString(DBPreferencePage.PASSWORD_KEY);
		// 生成一个数据库连接
		try {
			Class.forName(className);
			con = DriverManager.getConnection(url, username, password);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}
		return con;
	}

	// public static Connection getConnection() {
	// if (con == null) {
	// try {
	// System.out.print("aaaaaaaaaaaa");
	// Class.forName("com.mysql.jdbc.Driver");
	// System.out.print("aaaaaaaaaaaa111");
	// con = DriverManager
	// .getConnection("jdbc:mysql://localhost/com.zdh.sms?user=root&password=root");
	// System.out.print(con);
	// } catch (ClassNotFoundException e) {
	// e.printStackTrace();
	// } catch (SQLException e) {
	// e.printStackTrace();
	// }
	// }
	//
	// return con;
	// }

	// 提供一个真正关闭Connection的方法
	public static void closeConnection() {
		if (con == null)
			return;
		try {
			con.close();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		con = null;
	}
}