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  • 利用AOP实现SqlSugar自动事务

    先看一下效果,带接口层的三层架构:

    BL层:

      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;
              }
          }
    

    假设GetStudentList方法里的mStudentDa.GetStudents和mValueService.FindAll不是查询操作,而是更新操作,当一个失败另一个需要回滚,就需要在同一个事务里,当一个出现异常就要回滚事务。

    特性TransactionCallHandler就表明当前方法需要开启事务,并且当出现异常的时候回滚事务,方法执行完后提交事务。

    DA层:

     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();
             }
         }
    

    SqlSugar做一下包装

     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, //默认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("创建SqlSugarClient失败");
             }
             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("内部错误: SqlSugarClient已丢失.");
                 }
                 return id;
             }
    
             public static void BeginTran()
             {
                 var instance=GetInstance();
                 //开启事务
                 if (!instance.IsBeginTran)
                 {
                     instance.SqlSugarClient.Ado.BeginTran();
                     instance.IsBeginTran = true;
                 }
             }
    
             public static void CommitTran()
             {
                 var id = GetId();
                 if (!_cache.ContainsKey(id))
                     throw new Exception("内部错误: SqlSugarClient已丢失.");
                 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("内部错误: SqlSugarClient已丢失.");
                 _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("内部错误: SqlSugarClient已丢失.");
                 _cache[id].TranCount++;
             }
             public static void TranCountMunisOne()
             {
                 var id = GetId();
                 if (!_cache.ContainsKey(id))
                     throw new Exception("内部错误: SqlSugarClient已丢失.");
                 _cache[id].TranCount--;
             }
         }
    

    _cache保存SqlSugar实例,_threadLocal确保同一线程下取出的是同一个SqlSugar实例。

    不知道SqlSugar判断当前实例是否已经开启事务,所以又将SqlSugar包了一层。

      public class SqlClient
         {
             public SqlSugarClient SqlSugarClient;
             public bool IsBeginTran = false;
             public int TranCount = 0;
    
             public SqlClient(SqlSugarClient sqlSugarClient)
             {
                 this.SqlSugarClient = sqlSugarClient;
             }
         }
    

    IsBeginTran标识当前SqlSugar实例是否已经开启事务,TranCount是一个避免事务嵌套的计数器。

    一开始的例子

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

    TransactionCallHandler表明该方法要开启事务,但是如果mValueService.FindAll也标识了TransactionCallHandler,又要开启一次事务?所以用TranCount做一个计数。

    使用Castle.DynamicProxy

    要实现标识了TransactionCallHandler的方法实现自动事务,使用Castle.DynamicProxy实现BL类的代理

    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();
       //输出是
       //before
       //My Mehod
       //after
    

    before就是要开启事务的地方,after就是提交事务的地方
    最后实现

      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与Castle.DynamicProxy结合使用

    创建代理的时候一个BL类就要一次操作

     proxyGenerate.CreateClassProxy<MyClass>(t);
    

    而且项目里BL类的实例化是交给IOC容器控制的,我用的是Autofac。当然Autofac和Castle.DynamicProxy是可以结合使用的

    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>();
            }
        }
    
    
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  • 原文地址:https://www.cnblogs.com/jaycewu/p/7733114.html
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