Class BaseDao

src/main/java/smbms/dao/BaseDao.java:12–146

操作数据库的基本类

 * 操作数据库的基本类
 */
public class BaseDao {
    static {
        init();
    }

    private static String driver;
    private static String url;
    private static String user;
    private static String password;

    /**
     * 读取配置文件对数据库初始化，使用静态代码块在类加载前调用
     */
    public static void init() {
        InputStream resourceAsStream = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");
        Properties properties = new Properties();

        try {
            properties.load(resourceAsStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
        driver = properties.getProperty("driver");
        url = properties.getProperty("url");
        user = properties.getProperty("user");
        password = properties.getProperty("password");
    }

    /**
     * 此方法获得一个connection连接
     *
     * @return
     */
    public static Connection getConnection() {
        //加载驱动
        try {
            Class.forName(driver);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        //获取连接
        Connection connection = null;
        try {
            connection = DriverManager.getConnection(url, user, password);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return connection;
    }

    /**
     * 查询操作
     * 获取service层统一的connection对象，补充预编译sql语句，返回结果集
     * @param connection
     * @param pstm
     * @param resultSet
     * @param sql
     * @param params