利用AOP實現(xiàn)SqlSugar自動事務

來源：本站原創(chuàng)|時間：2020-01-10|欄目：C#教程|點擊：次

本文實例為大家分享了如何利用AOP實現(xiàn)SqlSugar自動事務，供大家參考，具體內容如下

先看一下效果,帶接口層的三層架構:

BL層：

 public class StudentBL : IStudentService
   {
     private ILogger mLogger;
     private readonly IStudentDA mStudentDa;
     private readonly IValueService mValueService;

     public StudentService(IStudentDA studentDa,IValueService valueService)
     {
       mLogger = LogManager.GetCurrentClassLogger();
       mStudentDa = studentDa;
       mValueService = valueService;

     }

     [TransactionCallHandler]
     public IList<Student> GetStudentList(Hashtable paramsHash)
     {
       var list = mStudentDa.GetStudents(paramsHash);
       var value = mValueService.FindAll();
       return list;
     }
   }

假設GetStudentList方法里的mStudentDa.GetStudents和mValueService.FindAll不是查詢操作，而是更新操作，當一個失敗另一個需要回滾，就需要在同一個事務里，當一個出現(xiàn)異常就要回滾事務。

特性TransactionCallHandler就表明當前方法需要開啟事務，并且當出現(xiàn)異常的時候回滾事務,方法執(zhí)行完后提交事務。

DA層：

 public class StudentDA : IStudentDA
   {

     private SqlSugarClient db;
     public StudentDA()
     {
       db = SugarManager.GetInstance().SqlSugarClient;
     }
     public IList<Student> GetStudents(Hashtable paramsHash)
     {
       return db.Queryable<Student>().AS("T_Student").With(SqlWith.NoLock).ToList();
     }
   }

對SqlSugar做一下包裝

 public class SugarManager
   {
     private static ConcurrentDictionary<string,SqlClient> _cache =
       new ConcurrentDictionary<string, SqlClient>();
     private static ThreadLocal<string> _threadLocal;
     private static readonly string _connStr = @"Data Source=localhost;port=3306;Initial Catalog=thy;user id=root;password=xxxxxx;Charset=utf8";
     static SugarManager()
     {
       _threadLocal = new ThreadLocal<string>();
     }

     private static SqlSugarClient CreatInstance()
     {
       SqlSugarClient client = new SqlSugarClient(new ConnectionConfig()
       {
         ConnectionString = _connStr, //必填
         DbType = DbType.MySql, //必填
         IsAutoCloseConnection = true, //默認false
         InitKeyType = InitKeyType.SystemTable
       });
       var key=Guid.NewGuid().ToString().Replace("-", "");
       if (!_cache.ContainsKey(key))
       {
         _cache.TryAdd(key,new SqlClient(client));
         _threadLocal.Value = key;
         return client;
       }
       throw new Exception("創(chuàng)建SqlSugarClient失敗");
     }
     public static SqlClient GetInstance()
     {
       var id= _threadLocal.Value;
       if (string.IsNullOrEmpty(id)||!_cache.ContainsKey(id))
         return new SqlClient(CreatInstance());
       return _cache[id];
     }


     public static void Release()
     {
       try
       {
         var id = GetId();
         if (!_cache.ContainsKey(id))
           return;
         Remove(id);
       }
       catch (Exception e)
       {
         throw e;
       }
     }
     private static bool Remove(string id)
     {
       if (!_cache.ContainsKey(id)) return false;

       SqlClient client;

       int index = 0;
       bool result = false;
       while (!(result = _cache.TryRemove(id, out client)))
       {
         index++;
         Thread.Sleep(20);
         if (index > 3) break;
       }
       return result;
     }
     private static string GetId()
     {
       var id = _threadLocal.Value;
       if (string.IsNullOrEmpty(id))
       {
         throw new Exception("內部錯誤: SqlSugarClient已丟失.");
       }
       return id;
     }

     public static void BeginTran()
     {
       var instance=GetInstance();
       //開啟事務
       if (!instance.IsBeginTran)
       {
         instance.SqlSugarClient.Ado.BeginTran();
         instance.IsBeginTran = true;
       }
     }

     public static void CommitTran()
     {
       var id = GetId();
       if (!_cache.ContainsKey(id))
         throw new Exception("內部錯誤: SqlSugarClient已丟失.");
       if (_cache[id].TranCount == 0)
       {
         _cache[id].SqlSugarClient.Ado.CommitTran();
         _cache[id].IsBeginTran = false;
       }
     }

     public static void RollbackTran()
     {
       var id = GetId();
       if (!_cache.ContainsKey(id))
         throw new Exception("內部錯誤: SqlSugarClient已丟失.");
       _cache[id].SqlSugarClient.Ado.RollbackTran();
       _cache[id].IsBeginTran = false;
       _cache[id].TranCount = 0;
     }

     public static void TranCountAddOne()
     {
       var id = GetId();
       if (!_cache.ContainsKey(id))
         throw new Exception("內部錯誤: SqlSugarClient已丟失.");
       _cache[id].TranCount++;
     }
     public static void TranCountMunisOne()
     {
       var id = GetId();
       if (!_cache.ContainsKey(id))
         throw new Exception("內部錯誤: SqlSugarClient已丟失.");
       _cache[id].TranCount--;
     }
   }

_cache保存SqlSugar實例，_threadLocal確保同一線程下取出的是同一個SqlSugar實例。

不知道SqlSugar判斷當前實例是否已經開啟事務，所以又將SqlSugar包了一層。

 public class SqlClient
   {
     public SqlSugarClient SqlSugarClient;
     public bool IsBeginTran = false;
     public int TranCount = 0;

     public SqlClient(SqlSugarClient sqlSugarClient)
     {
       this.SqlSugarClient = sqlSugarClient;
     }
   }

IsBeginTran標識當前SqlSugar實例是否已經開啟事務，TranCount是一個避免事務嵌套的計數(shù)器。

一開始的例子

 [TransactionCallHandler]
      public IList<Student> GetStudentList(Hashtable paramsHash)
      {
        var list = mStudentDa.GetStudents(paramsHash);
        var value = mValueService.FindAll();
        return list;
      }

TransactionCallHandler表明該方法要開啟事務，但是如果mValueService.FindAll也標識了TransactionCallHandler,又要開啟一次事務？所以用TranCount做一個計數(shù)。

使用Castle.DynamicProxy

要實現(xiàn)標識了TransactionCallHandler的方法實現(xiàn)自動事務，使用Castle.DynamicProxy實現(xiàn)BL類的代理

Castle.DynamicProxy一般操作

 public class MyClass : IMyClass
  {
    public void MyMethod()
    {
      Console.WriteLine("My Mehod");
    }
 }
 public class TestIntercept : IInterceptor
   {
     public void Intercept(IInvocation invocation)
     {
       Console.WriteLine("before");
       invocation.Proceed();
       Console.WriteLine("after");
     }
   }

  var proxyGenerate = new ProxyGenerator();
  TestIntercept t=new TestIntercept();
  var pg = proxyGenerate.CreateClassProxy<MyClass>(t);
  pg.MyMethod();
  //輸出是
  //before
  //My Mehod
  //after

before就是要開啟事務的地方，after就是提交事務的地方

最后實現(xiàn)

 public class TransactionInterceptor : IInterceptor
   {
     private readonly ILogger logger;
     public TransactionInterceptor()
     {
       logger = LogManager.GetCurrentClassLogger();
     }
     public void Intercept(IInvocation invocation)
     {
       MethodInfo methodInfo = invocation.MethodInvocationTarget;
       if (methodInfo == null)
       {
         methodInfo = invocation.Method;
       }

       TransactionCallHandlerAttribute transaction =
         methodInfo.GetCustomAttributes<TransactionCallHandlerAttribute>(true).FirstOrDefault();
       if (transaction != null)
       {
         SugarManager.BeginTran();
         try
         {
           SugarManager.TranCountAddOne();
           invocation.Proceed();
           SugarManager.TranCountMunisOne();
           SugarManager.CommitTran();
         }
         catch (Exception e)
         {
           SugarManager.RollbackTran();
           logger.Error(e);
           throw e;
         }

       }
       else
       {
         invocation.Proceed();
       }
     }
   }
   [AttributeUsage(AttributeTargets.Method, Inherited = true)]
   public class TransactionCallHandlerAttribute : Attribute
   {
     public TransactionCallHandlerAttribute()
     {

     }
   }

Autofac與Castle.DynamicProxy結合使用

創(chuàng)建代理的時候一個BL類就要一次操作

 proxyGenerate.CreateClassProxy<MyClass>(t);

而且項目里BL類的實例化是交給IOC容器控制的，我用的是Autofac。當然Autofac和Castle.DynamicProxy是可以結合使用的

using System.Reflection;
using Autofac;
using Autofac.Extras.DynamicProxy;
using Module = Autofac.Module;
public class BusinessModule : Module
  {
    protected override void Load(ContainerBuilder builder)
    {
      var business = Assembly.Load("FTY.Business");
      builder.RegisterAssemblyTypes(business)
        .AsImplementedInterfaces().InterceptedBy(typeof(TransactionInterceptor)).EnableInterfaceInterceptors();
      builder.RegisterType<TransactionInterceptor>();
    }
  }

以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持我們。

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