JavaWeb原生JDBC封装

肝作业时候看见要求，需要使用原生访问数据库增删改查，把以前写的翻出来，怕忘记了，记录一下。

Dao层

封装工具类BaseDao.java

public class BaseDao {
    public static String driver;
    public static String url;
    public static String username;
    public static String password;

    static {
        Properties properties = new Properties();
        InputStream input = BaseDao.class.getClassLoader().getResourceAsStream("db.properties");
        try {
            properties.load(input);
        } catch (IOException e) {
            e.printStackTrace();
        }
        driver = properties.getProperty("driver");
        url = properties.getProperty("url");
        username = properties.getProperty("username");
        password = properties.getProperty("password");
    }

    public static Connection getConnection() {
        Connection connection = null;
        try {
            Class.forName(driver);
            connection = DriverManager.getConnection(url, username, password);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
        return connection;
    }

    //查
    public static ResultSet execute(Connection connection, ResultSet rs, PreparedStatement preparedStatement, String sql, Object[] params) throws SQLException {
        preparedStatement = connection.prepareStatement(sql);

        for (int i = 0; i < params.length; i++) {
            preparedStatement.setObject(i + 1, params[i]);
        }

        rs = preparedStatement.executeQuery();
        return rs;
    }

    //增删改
    public static int execute(Connection connection, PreparedStatement pstm,String sql, Object[] params) throws SQLException {
        pstm = connection.prepareStatement(sql);

        for (int i = 0; i < params.length; i++) {
            pstm.setObject(i + 1, params[i]);
        }

        int updateRows = pstm.executeUpdate();
        return updateRows;
    }

    public static boolean CloseResource(Connection connection, PreparedStatement preparedStatement, ResultSet rs) {
        boolean flag = true;
        try {
            if (rs != null) {
                rs.close();
//                GC回收
                rs = null;
            }
            if (preparedStatement != null) {
                preparedStatement.close();
                preparedStatement = null;
            }
            if (connection != null) {
                connection.close();
                connection = null;
            }
        } catch (SQLException throwables) {
            throwables.printStackTrace();
            flag = false;
        }

        return flag;
    }

}

UserDao.java

没写全，因为作业就这俩功能

public interface UserDao {

    User login(String name);

    int register(User user);
}

UserDaoImpl.java

public class UserDaoImpl implements UserDao {
    @Override
    public User login(Connection connection, String name) throws SQLException {
        PreparedStatement pst = null;
        ResultSet rs = null;
        User user = null;

        if (connection != null) {
            String sql = "SELECT * FROM users where name=?";
            Object[] params = {name};
            rs = BaseDao.execute(connection, rs, pst, sql, params);

            if (rs.next()) {
                user = new User();
                user.setId(rs.getInt("id"));
                user.setName(rs.getString("name"));
                user.setPassword(rs.getString("password"));
                user.setEmail(rs.getString("email"));
                user.setBirthday(rs.getString("birthday"));
            }
            BaseDao.CloseResource(connection, pst, rs);
        }
        return user;
    }

    @Override
    public int register(Connection connection, User user) throws SQLException {
        PreparedStatement pstm = null;
        int updateNum = 0;
        if (connection != null) {
            String sql = "insert into users (id,name,password," +
                    "email,birthday) " +
                    "values(?,?,?,?,?)";
            Object[] params = {user.getId(), user.getName(), user.getPassword(), user.getEmail(), user.getEmail()};
            updateNum = BaseDao.execute(connection, pstm, sql, params);
            BaseDao.CloseResource(null, pstm, null);
        }
        return updateNum;
    }
}

Service层

UserService.java

public interface UserService {

    User Login(String name);

    Boolean Register(User user);

}

 UserServiceImpl.java

public class UserServiceImpl implements UserService {

    private UserDao userDao;

    public UserServiceImpl() {
        userDao = new UserDaoImpl();
    }

    @Override
    public User Login(String name) {
        Connection connection = null;
        User user = null;

        connection = BaseDao.getConnection();
        try {
            user = userDao.login(connection, name);
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        } finally {
            BaseDao.CloseResource(connection, null, null);
        }

        return user;
    }

    @Override
    public Boolean Register(User user) {
        Boolean flag = false;
        Connection connection = null;
        try {
            //获得连接
            connection = BaseDao.getConnection();
            //开启JDBC事务管理
            connection.setAutoCommit(false);
            int updateRows = userDao.register(connection, user);
            connection.commit();
            if (updateRows > 0) {
                flag = true;
                System.out.println("add success!");
            } else {
                System.out.println("add failed!");
            }
        } catch (Exception e) {
            e.printStackTrace();
            try {
                System.out.println("rollback==");
                //失败就回滚
                connection.rollback();
            } catch (SQLException exception) {
                exception.printStackTrace();
            }
        } finally {
            //在service层进行connection连接的关闭
            BaseDao.CloseResource(connection, null, null);
        }
        return flag;
    }
}

原生写的真麻烦，果然还是框架好用。

Controller层

扛不住了，浅用一下注解，省的写web.xml了

LoginServlet.java

@WebServlet(name = "LoginServlet", value = "/login")
public class LoginServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        resp.setContentType("text/html;charset=UTF-8");

        String username = req.getParameter("username");
        String password = req.getParameter("password");

        UserService userImpl = new UserServiceImpl();

        User user = userImpl.Login(username);

        if (!user.getName().isEmpty()) {
            String ps = user.getPassword();
            if (ps.equals(password)) {
                req.getRequestDispatcher("/success.jsp").forward(req, resp);
            } else {
                req.getRequestDispatcher("/error.jsp").forward(req, resp);
            }
        } else {
            req.getRequestDispatcher("/error.jsp").forward(req, resp);
        }
    }
}

RegisterServlet.java

@WebServlet(name = "RegisterServlet", value = "/register")
public class RegisterServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doGet(req, resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        String email = req.getParameter("email");
        String birthday = req.getParameter("birthday");

        UserService userService = new UserServiceImpl();
        Boolean isRegister = userService.Register(new User(10, username, password, email, birthday));

        if (isRegister) {
            req.getRequestDispatcher("/registerSuccess.jsp").forward(req,resp);
        } else {
            req.getRequestDispatcher("/registerFailed.jsp").forward(req,resp);
        }
    }
}

差不多了，jsp就不贴了，很简陋。