敲完三层后,感觉还是对三层架构没有那么亲切,和小伙伴交流后,他们说多多敲几遍,就懂了,其实就是那么几条线,所以:不管会不会,先去做吧!
下面是关于七层的包图:
我的解决方案:
代码部分:
U层:
<span style="font-family:KaiTi_GB2312;font-size:18px;">Imports Login.Entity.UserEntity Imports Facade Imports System.Net.Dns Public Class FrmLogin Private Sub btnOK_Click(sender As Object,e As EventArgs) Handles btnOK.Click Dim strResult1 As Boolean Dim strResult2 As Boolean Dim FacadeLogin As New Facade.LoginFacade '定义一个外观对象 Dim UserInfo As New Login.Entity.UserEntity '定义一个实体类对象 '判断文本框 If txtUsername.Text = "" Then MessageBox.Show("温馨提示,思密达输入用户名","",MessageBoxButtons.OK,MessageBoxIcon.Exclamation) txtUsername.Text = "" '设置为空 txtUsername.Focus() '用户名获得焦点 Exit Sub End If If txtPassword.Text = "" Then MessageBox.Show("思密达,请输入密码",MessageBoxIcon.Exclamation) txtPassword.Text = "" '设置为空 txtPassword.Focus() '密码框获得焦点 Exit Sub End If Try '将文本框中的参数传递给实体 UserInfo.UserName = txtUsername.Text.Trim() '将用户名和密码赋值给实体类的对象UserinfoUserName;Password属性; UserInfo.Password = txtPassword.Text.Trim() '从而Userinfo获取了U层的参数,通过外观层,传递到B层进行判断; strResult1 = FacadeLogin.CheckUser(UserInfo) '将U层的用户名通过外观层传到B层,得到外观的返回值; strResult2 = FacadeLogin.CheckPwd(UserInfo) If strResult1 = False Or strResult2 = False Then '通过返回值来判断用户是否存在; MsgBox("用户名或密码不正确!") txtUsername.Text = "" txtPassword.Text = "" txtUsername.Focus() Else MsgBox("登录成功!Amazing") End If Catch ex As Exception MsgBox("用户不存在或者密码不正确!") txtUsername.Text = "" txtPassword.Text = "" txtUsername.Focus() End Try End Sub Private Sub btnCancel_Click(sender As Object,e As EventArgs) Handles btnCancel.Click Me.Close() '关闭窗体 End Sub Private Sub FrmLogin_Load(sender As Object,e As EventArgs) Handles MyBase.Load '获取计算机名称 Dim Address() As System.Net.IPAddress 'class system.net.IPAddress提供网际协议(IP)地址; 'class system.net.dns提供简单的域名解析功能; 'GetHostName()获取本地主机名; 'AddressList获取或设置与主机关联的IP列表; Address = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName()).AddressList txtComputer.Text = System.Net.Dns.GetHostName().ToString() End Sub End Class</span>
Façade层:
<span style="font-family:KaiTi_GB2312;font-size:18px;">Imports Login.Entity Imports Login.BLL Imports System.Reflection Public Class LoginFacade Public Function CheckUser(ByVal UserInfo As Login.Entity.UserEntity) As Boolean Dim isUserExists As New Login.BLL.UserBLL() '实例化B层UserBLL类对象; Dim flag As Boolean flag = isUserExists.IsUserExists(UserInfo) '判断是否存在该用户 Return flag End Function Public Function CheckPwd(ByVal UserInfo As Login.Entity.UserEntity) As Boolean Dim isPwd As New Login.BLL.UserBLL() '实例化UserBLL对象; Dim flag1 As Boolean flag1 = isPwd.IsPwdRight(UserInfo) '判断userinfo对象的密码是否存在; Return flag1 End Function End Class</span>
B层:
<span style="font-family:KaiTi_GB2312;font-size:18px;">Public Class UserBLL '检查用户是否存在 Public Function IsUserExists(ByVal UserInfo As Login.Entity.UserEntity) As Boolean Dim Iuser As IDAL.IuserInfoDAL '调用创建用户的工厂方法 Iuser = Factory.LoginFactory.CreateUserInfo Dim table As DataTable Dim flag As Boolean table = Iuser.selectUser(UserInfo) '由于在sqlhelper中以表格的形式存在(adataset.Tables(0)),且开头第一列表示为0,所以Item(0)表示为用户名; If table.Rows(0).Item(0) = 0 Then '第一行第一列 flag = False Else flag = True End If Return flag End Function '查看密码是否正确 Public Function IsPwdRight(ByVal UserInfo As Login.Entity.UserEntity) As Boolean Dim Iuser As IDAL.IuserInfoDAL Dim table As DataTable '中间变量用来存储数据 Dim flag1 As Boolean Iuser = Factory.LoginFactory.CreateUserInfo '调用工厂方法的Createuserinfo来创建iuser; table = Iuser.selectUser(UserInfo) '调用接口的方法selectUser If table.Rows(0).Item(0) = 0 Then flag1 = False Else flag1 = True End If Return flag1 End Function End Class</span>
Factory层:
<span style="font-family:KaiTi_GB2312;font-size:18px;">Imports System.Configuration Imports System.Reflection '使用反射来帮我们克服抽象工厂模式的先天不足 Imports Login.IDAL Imports Login.DAL Public Class LoginFactory '读配置文件,D层的每个类在配置文件里面对应一个key '下面这句式把key变成变量,然后在下面这个方法中用这个变量就可以应用D层里面这个类了; Dim strDB As String = System.Configuration.ConfigurationSettings.AppSettings("DBString") ''' <summary> ''' ’实例化LoginDAL中users表中一个类 ''' </summary> ''' <returns></returns> ''' <remarks></remarks> Public Shared Function CreateUserInfo() As Login.IDAL.IuserInfoDAL 'CType是一个内联函数,将前面的部分转换为后半部分; 'LoginDAL为程序集名称; 'Login.DAL为命名空间名称; 'IuserInfoDAL 为要实例化的“类名”; 'CreateUserInfo ’创建实例; Return CType(Assembly.Load("LoginDAL").CreateInstance("Login.DAL" & "." & "UserDAL"),IuserInfoDAL) End Function End Class</span>
接口层:
<span style="font-family:KaiTi_GB2312;font-size:18px;">Imports Login.Entity Public Interface IuserInfoDAL 'UserInfo为用户的实体,是由实体类实例化而来的 '即所谓的传实体 '此接口定义了一个方法,用来检测用户是否存在 Function selectUser(ByVal UserInfo As Login.Entity.UserEntity) As DataTable End Interface</span>
D层:
<span style="font-family:KaiTi_GB2312;font-size:18px;">Imports System.Data.sqlClient 'system.data.sqlClient命名空间是sql SERVER的.netframework数据提供的程序 'sql server的.net framework数据提供程序描述了一个类集合,这个类用于访问托管中的sql server数据库; Imports Login.Entity Imports Login.IDAL Imports sqlHelper Public Class UserDAL : Implements IDAL.IuserInfoDAL '实现接口中的方法; '声明并实例化sqlhelper类 Private sqlHelper As sqlHelper.sqlhelper = New sqlHelper.sqlhelper Public Function selectUser(UserInfo As Login.Entity.UserEntity) As DataTable Implements IuserInfoDAL.selectUser Dim sql As String Dim table As DataTable '中间变量用于存储从数据库中查找信息 Dim sqlConnectStr As String = "server =ZLT;database=Login;uid=sa;pwd=123" '声明并实例化参数数组 Dim sqlParams As sqlParameter() = {New sqlParameter("@UserName",UserInfo.UserName),New sqlParameter("@Password",UserInfo.Password)} sql = "select * from Users where UserName=@UserName and Password=@Password" 'sql是查询到的信息; '下句为调用sqlHelper类中的GetDataTable()方法来执行查询,并获取返回值; table = sqlHelper.GetDataTable(sql,CommandType.Text,sqlParams) Return table End Function End Class</span>
Entity层:
<span style="font-family:KaiTi_GB2312;font-size:18px;">Public Class UserEntity '区别变量的名字,变量的名字比数据库多“_” Private _UserName As String Private _Password As String Private _UserID As String Private _level As String Private _Holder As String '以下为可读写属性,名字和数据库中的一样 Public Property UserName() As String Get Return _UserName End Get Set(value As String) _UserName = value End Set End Property Public Property Password() As String Get Return _Password End Get Set(value As String) _Password = value End Set End Property End Class</span>
sqlHelper层:
为什么要用sqlHelper?
sqlhelper封装了对数据库的增删改查,所以减少了代码的量,提高了系统性能;具体见:点我
<span style="font-family:KaiTi_GB2312;font-size:18px;">Imports System.Data.sqlClient Imports System.Configuration Imports System.Data Imports System.Reflection Public Class sqlhelper 'configurationManager表示读配置文件; 'appsetting获取配置文件的数据; Public Shared ConnectionString As String = ConfigurationManager.AppSettings("sqlConnectStr") 'sqlDataAdapter表示用于填充Data.Dataset和更新sql SERVER数据库的一组数组命令和一个数据库连接; Private Shared Property adaptor As sqlDataAdapter '''<summary> '''执行带参数的查询操作 '''</summary> ''' <param name="cmdTxt">参数cmdTxt为所要执行的sql语句</param> ''' <param name="cmdType">查询时的查询方式</param> ''' <param name="paras">查询时的命令参数paras</param> ''' <returns>查询后以表示的方式返回,如下面adataset.Tables(0)</returns> ''' <remarks></remarks> Public Shared Function GetDataTable(ByVal cmdTxt As String,ByVal cmdType As CommandType,ByVal paras As sqlParameter()) As DataTable Dim conn As sqlConnection = New sqlConnection(ConnectionString) '建立数据库连接; Dim cmd As sqlCommand '定义命令变量; Dim adaptor As sqlDataAdapter '定义数据库适配器; Dim adataset As DataSet '定义并实例化数据库缓冲区对象,即从数据库传入对象; cmd = New sqlCommand(cmdTxt,conn) '在Conn上实例化命令变量,并执行cmdType; cmd.CommandType = cmdType '执行命令的类型 cmd.Parameters.AddRange(paras) '命令执行时的参数 adaptor = New sqlDataAdapter(cmd) '将结果绑定到数据库适配器变量adaptor上面; adataset = New DataSet 'dataset表示数据内存中缓存; Try '如果数据库连接状态为关闭则将其打开; If conn.State = ConnectionState.Closed Then conn.Open() End If adaptor.Fill(adataset) '向adaptor对象中填充要查询的数据; Catch ex As Exception '错误处理程序,出错则提示 MsgBox(ex.Message,"数据库操作!") Finally '如果连接状态为打开,则将其关闭,释放内存; If conn.State = ConnectionState.Open Then conn.Close() End If End Try '以表格的形式返回结果 Return adataset.Tables(0) End Function Function GetDataTable() As DataTable Throw New NotImplementedException End Function End Class</span>
生成依赖项关系图:
小结:
这个阶段总是在参考别人的博客学习,学到了很多东西,自己也亲自调试了好多错误(具体错误:点我),成长了好多,在以后机房重构的过程中,希望自己多多实践自己的想法。
1、 站在巨人的肩膀上学习,让我们知道了许多以前不知道的地方;
感谢您的宝贵时间~~~
原文链接:https://www.f2er.com/vb/257147.html