使用Easy4net编写代码生成器

    在项目中经常要手动创建和数据库对应的实体类，如果数据库表比较多或者表字段比较多，那会是一个工作量非常大的事情，所以我根据自己的需求写了一个简单的代码生成工具，工具使用Easy4net框架开发。

下面是代码目录结构：

项目开始预备步骤：

1. 创建项目EntityCodeBuilder

2. 引入Easy4net项目源码

3. 创建Entity类库

4. 创建TableName和TableColumn类

5. 在App.config配置文件中配置数据库连接信息

TableName源码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace EntityCodeBuilder.Entity
{
    public class TableName
    {
        public string Name { get; set; }
    }
}

TableColumn源码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace EntityCodeBuilder.Entity
{
    public class TableColumn
    {
        public string Name { get; set; }
        public string Type { get; set; }
        public string IsIdentity { get; set; }
        public string IsPrimaryKey { get; set; }
        public string IsNull { get; set; }
        
    }
}

App.config配置文件代码：

  <appSettings>
    <add key="DbType" value="sqlserver"/>
    <add key="connectionString" value="Data Source=.;Initial Catalog=test;User ID=test;Password=test123;Trusted_Connection=no;Min Pool Size=10;Max Pool Size=100;"/>

    <!--<add key="DbType" value="mysql"/>
    <add key="connectionString" value="Data Source=.;port=8001;User ID=test;Password=123456;DataBase=test;Min Pool Size=10;Max Pool Size=100;"/>-->
    
  </appSettings>

UI上的代码不细说了，主要是有几个类的代码：

TableHelper中的代码，获取数据库所有表名：

/// <summary>  
        /// 获取数据库所有表名 
        /// </summary>  
        /// <param name="connection"></param>  
        /// <returns></returns>  
        public static List<TableName> GetTables()
        {
            SqlConnection connection = (SqlConnection)DbFactory.CreateDbConnection(AdoHelper.ConnectionString);
            List<TableName> tablelist = new List<TableName>();
            try
            {
                if (connection.State == ConnectionState.Closed)
                {
                    connection.Open();
                    DataTable objTable = connection.GetSchema("Tables");
                    foreach (DataRow row in objTable.Rows)
                    {
                        TableName tb = new TableName();
                        tb.Name = row[2].ToString();
                        tablelist.Add(tb);
                    }
                }
            }
            catch(Exception e)
            {
                throw e;
            }
            finally
            {
                if (connection != null && connection.State == ConnectionState.Closed)
                {
                    connection.Dispose();
                }
            }

            return tablelist;
        }

TableHelper中的代码，根据表名获取所有列：

/// <summary>  
        /// 获取字段  
        /// </summary>  
        /// <param name="connection"></param>  
        /// <param name="TableName"></param>  
        /// <returns></returns>  
        public static List<TableColumn> GetColumnField(string TableName)
        {
            StringBuilder sb = new StringBuilder();
            sb.Append(" SELECT a.name,");
            sb.Append(" b.name as type,");
            sb.Append(" CASE COLUMNPROPERTY(a.id,a.name,'IsIdentity') WHEN 1 THEN '√' ELSE '' END as IsIdentity, ");
            sb.Append(" CASE WHEN EXISTS ( SELECT * FROM sysobjects WHERE xtype='PK' AND name IN ( SELECT name FROM sysindexes WHERE id=a.id AND indid IN ( SELECT indid FROM sysindexkeys ");
            sb.Append(" WHERE id=a.id AND colid IN ( SELECT colid FROM syscolumns WHERE id=a.id AND name=a.name ) ) ) ) THEN '√' ELSE '' END as IsPrimaryKey,");
            sb.Append(" CASE a.isnullable WHEN 1 THEN '√' ELSE '' END as IsNull ");
            sb.Append(" FROM syscolumns a ");
            sb.Append(" LEFT  JOIN systypes      b ON a.xtype=b.xusertype ");
            sb.Append(" INNER JOIN sysobjects    c ON a.id=c.id AND c.xtype='U' AND c.name<>'dtproperties' ");
            sb.Append(" LEFT  JOIN syscomments   d ON a.cdefault=d.id ");
            sb.Append(" WHERE c.name = '").Append(TableName).Append("' ");
            sb.Append(" ORDER BY c.name, a.colorder");

            //使用Easy4net框架查询数据
            List<TableColumn> list = db.FindBySql<TableColumn>(sb.ToString());
            return list;
        }

知道表名，字段名称，字段类型后，要生成实体类，需要根据数据库中的数据类型转换为C#中的类型：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace WindowsDemo
{
    public class TypeHelper
    {
        public static string GetType(string type)
        {
            string newType = "String";

            switch (type)
            {
                case "varchar":
                case "varchar2":
                case "nvarchar":
                case "char":
                    newType = "String";
                    break;
                case "int":
                case "integer":
                case "bit":
                case "smallint":
                    newType = "int";
                    break;
                case "long":
                case "bitint":
                    newType = "long";
                    break;
                case "date":
                case "datetime":
                case "datetime2":
                case "datetimeoffset":
                    newType = "DateTime";
                    break;
                case "decimal":
                case "number":
                case "money":
                case "numeric":
                    newType = "Decimal";
                    break;
                case "double":
                    newType = "double";
                    break;
                case "float":
                    newType = "float";
                    break;
            }

            return newType;
        }
    }
}

下面就是生成代码的具体步骤了：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using EntityCodeBuilder.Entity;

namespace WindowsDemo
{
    public class CreateFileHelper
    {
        /// <summary>
        /// 创建类文件目录和文件
        /// </summary>
        /// <param name="tables">所有表</param>
        /// <param name="fileDir">文件目录</param>
        public static void Create(List<TableName> tables, string fileDir)
        {
            CreateDirectory(fileDir);
            foreach (TableName table in tables)
            {
                //实体类名称
                string entityName = GenVarName(table.Name);
                //实体类文件名
                string filePath = fileDir + entityName + ".cs";
                //文件是否存在
                bool exists = File.Exists(filePath);

                //创建文件
                FileStream fs = new FileStream(filePath, exists ? FileMode.Open : FileMode.Create, FileAccess.Write);
                StreamWriter sw = new StreamWriter(fs);

                //生成代码
                string code = CreateFileHelper.BuilderCode(table.Name);

                //写入代码到文件
                sw.WriteLine(code);

                sw.Close();
                fs.Close();
            }
        }

        /// <summary>
        /// 创建文件目录
        /// </summary>
        /// <param name="targetDir"></param>
        private static void CreateDirectory(string targetDir)
        {
            DirectoryInfo dir = new DirectoryInfo(targetDir);
            if (!dir.Exists)
                dir.Create();
        }

        /// <summary>
        /// 根据表名，生成代码
        /// </summary>
        /// <param name="tableName">表名</param>
        /// <returns></returns>
        public static string BuilderCode(string tableName)
        {
            string entityName = GenVarName(tableName);

            StringBuilder sb = new StringBuilder();
            sb.Append("using System;").Append("
");
            sb.Append("using System.Collections.Generic; ").Append("
");
            sb.Append("using System.Linq;  ").Append("
");
            sb.Append("using System.Text;  ").Append("
");
            sb.Append("using System.Text;  ").Append("
");
            sb.Append("namespace Easy4net.Entity  ").Append("
");
            sb.Append("{  ").Append("
");

            sb.Append("	 [Table(Name = "").Append(tableName).Append("")] ").Append("
");
            sb.Append("	 public class ").Append(entityName).Append("
");
            sb.Append("	 { ").Append("
");

            List<TableColumn> columns = TableHelper.GetColumnField(tableName);
            foreach (TableColumn column in columns)
            {
                string type = TypeHelper.GetType(column.Type);
                if (column.IsPrimaryKey == "√")
                {
                    //[Id(Name = "UserID", Strategy = GenerationType.INDENTITY)]
                    string strategy = "GUID";
                    if (column.IsIdentity == "√")
                    {
                        strategy = "INDENTITY";
                    }

                    sb.Append("		").Append("[Id(Name = "").Append(column.Name).Append("", Strategy = GenerationType.").Append(strategy).Append(")]").Append("
");
                }
                else
                {
                    sb.Append("		").Append("[Column(Name = "").Append(column.Name).Append("")]").Append("
");
                }

                string fieldName = GenVarName(column.Name);
                sb.Append("		").Append("public ").Append(type).Append(" ").Append(fieldName).Append("{ get; set; } 

");
            }

            sb.Append("	 } ").Append("
");
            sb.Append("}    ").Append("
");

            return sb.ToString();
        }

        /// <summary>
        /// 将数据库中变量名改为驼峰命名
        /// 如 user_name 改为 UserName
        /// </summary>
        /// <param name="name">变量名</param>
        /// <returns></returns>
        public static string GenVarName(string name)
        {
            string first = name.Substring(0, 1);
            name = name.Substring(1, name.Length - 1);
            name = first.ToUpper() + name;

            int index = name.IndexOf("_");
            while (index != -1)
            {
                if (name.Length >= index + 2)
                {
                    first = name.Substring(index + 1, 1);
                    string start = name.Substring(0, index);
                    string end = name.Substring(index + 2, name.Length - index - 2);
                    name = start + first.ToUpper() + end;

                    index = name.IndexOf("_");
                }
            }

            name = name.Replace("_", "");

            return name;
        }
    }
}

完成上面代码，这个工具的核心功能基本就完成了。

源码下载地址：点击下载