mysql 数据库链接状态确认实验(推荐)

1.起因：

在做一个小系统的时候，我想数据量交互不大，就都用一个链接执行算了，还能节省点资源，但是实际情况遇到了如下问题，在使用的过程中，有些数据操作会被转移到其他线程，这样；我这个简单的想法遇到了问题，因为一个现场在使用这个链接的时候，其他线程也会同步插入执行数据操作，这样一个链接就会面临共用的冲突，怎么办呢，有如下三种方案：

1.1.数据两次一次一联，一用，一释放。

1.2.强制是数据库的执行放到一个现场，那么得把所有的执行参数放到队列中，有数据支持的线程按照队列的顺序执行。也可以在使用的时候把链接索起来。这样强制的使数据的处理串行。

1.3.做一个内部的链接对象使用池，池中的对象可供服用，解决重复链接的问题，提供多个对象解决现场使用冲突的问题。

我选择了方案三，做了如下实验，记录如下

2.实验

2.1 确认数据链接状态，使用完的数据链接是什么状态呢？

2.1.1 目的：我想根据链接的状态判断链接是在使用中，还是可以给别人使用；就是在可以使用的情况下，我就用该链接执行，否则使用或者创建其他的链接。

代码。

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using System; using System.Data;   namespace 数据库链接状态确认 {      /// <summary>      /// 确认数据库通常执行完成是什么状态      /// </summary>      public class Test1:Singleton<Test1>      {          public void main()          {              test1();          }          private void test1()          {              DBmsqlSub dBmsqlSub = new DBmsqlSub();              string sql = "insert into tb1(v1) values(2)" ;              dBmsqlSub.ExecuteNonQuery(sql);              ConnectionState connectionState = dBmsqlSub.getState();              Console.WriteLine(connectionState);              dBmsqlSub.Close();          }      } }

结果，整理使用后的链接状态是open,那是不是open的时候就可以供别人使用了呢，要是在执行的时候也是open状态，那我就没有判定已经了。

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数据库链接状态确认 id0 index:1 isuser:False setuser:False Open

2.2 数据库在执行的时候，是不是有一个执行中的状态呢？

代码

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using System; using System.Threading.Tasks;   namespace 数据库链接状态确认 {      /// <summary>      /// 目的：确认执行中的数据状态      /// </summary>      class Test2:Singleton<Test2>      {          public void main() {              DBmsqlSub dBmsqlSub = new DBmsqlSub();              Task.Factory.StartNew(test2Exe, (Object)dBmsqlSub);              Task.Factory.StartNew(test2Exe, (Object)dBmsqlSub);              Task.Factory.StartNew(test2State, dBmsqlSub);          }          private void test2Exe( object dBmsqlSub)          {              int index = 1;              while ( true )              {                  index++;                  string sql = "insert into tb1(v1) values(" + index + ")" ;                  ((DBmsqlSub)dBmsqlSub).ExecuteNonQuery(sql);                  Task.Delay(200);              }          }          private void test2State( object dBmsqlSub)          {              while ( true )              {                  Console.WriteLine(((DBmsqlSub)dBmsqlSub).getState());              }          }      } }

行结果执：即使执行中，对象的链接状态依然是open，那么用链接状态作为链接是否可用的计划泡汤了，那就只能用自添加的对象来控制链接是否可用了。

Open
Open
Open
Open
id0
Open
Open
Open
Open
Open
Open

2.3 测试3：添加对象的状态，控制链接是否可用

2.3.1 代码

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using MySqlConnector; using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace 数据库链接状态确认 {      class Test3:Singleton<Test3>      {          public void main() {              test1();              //test1();          }          private void test1() {              Task.Factory.StartNew(test2Exe);              Task.Factory.StartNew(test2Exe);              Task.Factory.StartNew(test2Exe);          }          private void test2Exe()          {              int index = 1;              while ( true )              {                  index++;                  string sql = "insert into tb1(v1) values(" + index + ")" ;                  DBmsql.getMy().ExecuteNonQuery(sql);              }          }            private object MySqlDataReader(DBmsqlSub dBmsqlSub)          {              throw new NotImplementedException();          }            private void test2State( object dBmsqlSub)          {              while ( true )              {                  Console.WriteLine(((DBmsqlSub)dBmsqlSub).getState());              }          }      } }

2.3.2

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using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace 数据库链接状态确认 {      class DBmsql : Singleton<DBmsql>      {          List<DBmsqlSub> dBmsqlSubs = new List<DBmsqlSub>();          /// <summary>          /// 执行sql命令          /// </summary>          /// <param name="CommandText"></param>          public void ExecuteNonQuery(String CommandText)          {              getDBmsqlSub().ExecuteNonQuery(CommandText);          }            /// <summary>          /// 插入数据，并返回插入数据的id          /// </summary>          /// <param name="CommandText"></param>          /// <returns></returns>          public int insertReturn( string CommandText)          {              int ret = getDBmsqlSub().insertReturn(CommandText);              return ret;          }          /// <summary>          /// 执行并返回一个对象          /// </summary>          /// <param name="CommandText"></param>          /// <returns></returns>          public object ExecuteScalar( string CommandText)          {              object o = getDBmsqlSub().ExecuteScalar(CommandText);              return o;          }          /// <summary>          /// 获取数据处理对象          /// </summary>          /// <returns></returns>          private DBmsqlSub getDBmsqlSub()          {              DBmsqlSub ret = null ;                lock (dBmsqlSubs)              {                  //避免两个同时取到允许的状态                  foreach (DBmsqlSub dBmsqlSub in dBmsqlSubs)                  {                      if (!dBmsqlSub.IsUrse())                      {                          ret = dBmsqlSub;                          dBmsqlSub.setIsUser( true );                          Console.WriteLine( "get:" + ret.id);                          break ;                      }                  }                  //避免两个同时创建对象，产生结果列表的错误                  if (ret == null && dBmsqlSubs.Count<90)                  {                      DBmsqlSub dBmsqlSub = new DBmsqlSub();                      dBmsqlSubs.Add(dBmsqlSub);                      dBmsqlSub.setIsUser( true );                      ret = dBmsqlSub;                      Console.WriteLine( "get:" + ret.id);                  }              }              return ret;          }      } }

2.3.3

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using MySqlConnector; using System; using System.Collections.Generic; using System.Data; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace 数据库链接状态确认 {      public class Constand {          public static string mesConnStr = "server=localhost;port=3306;database=db1;user id=root;password=123456;Charset=utf8;" ;      }      class DBmsqlSub      {          static int index = 0;          public int id = 0;          private bool isUser = false ;          private static NLog.Logger logger = NLog.LogManager.GetCurrentClassLogger();          MySqlConnection mConn;          MySqlCommand mCmd;          public void setIsUser( bool value) {              lock ( this ) {                  Console.WriteLine( "index:" + index + " isuser:" + isUser+ " setuser:" + value);                  isUser = value;              }          }            public MySqlDataReader MySqlDataReader { get ; private set ; }            public DBmsqlSub()          {              id = index++;              try              {                  mConn = new MySqlConnection(Constand.mesConnStr);                  mConn.Open();                  mCmd = new MySqlCommand();                  mCmd.Connection = mConn;              }              catch (Exception e)              {                  logger.Error(e.ToString());              }          }          ~DBmsqlSub()          {              mConn.Close();          }          public void Close()          {              mConn.Close();          }          public bool isOpen()          {              if (mConn.State == ConnectionState.Closed)              {                  mConn.Open();              }              if (mConn.State == ConnectionState.Open)              {                  return true ;              }              else              {                  return false ;              }          }          public MySqlCommand getCmd()          {              return mCmd;          }          /// <summary>          /// 如果没有链接，就直接链接          /// </summary>          private void conn()          {              if (mConn.State != ConnectionState.Open)              {                  mConn.Open();              }          }            /// <summary>          /// 执行sql命令          /// </summary>          /// <param name="CommandText"></param>          public void ExecuteNonQuery(String CommandText)          {              //setIsUser(true);              mCmd.CommandText = CommandText;              try              {                  Console.WriteLine( "id" +id);                  mCmd.ExecuteNonQuery();              }              catch (Exception ex)              {                  logger.Error(ex.ToString());              }              finally {                  setIsUser( false );              }          }            /// <summary>          /// 插入数据，并返回插入数据的id          /// </summary>          /// <param name="CommandText"></param>          /// <returns></returns>          public int insertReturn( string CommandText)          {              setIsUser( true );              int ret = 0;              MySqlTransaction sqlTransaction = mConn.BeginTransaction();              try              {                  mCmd.CommandText = CommandText;                  object o = mCmd.ExecuteScalar();                  sqlTransaction.Commit();                  ret = int .Parse(o.ToString());              }              catch (Exception e)              {                  logger.Error(e.ToString());                  sqlTransaction.Rollback();              }              finally              {                  setIsUser( false );              }              return ret;          }          /// <summary>          /// 执行并返回一个对象          /// </summary>          /// <param name="CommandText"></param>          /// <returns></returns>          public object ExecuteScalar( string CommandText)          {              setIsUser( true );              object o = null ;              mCmd.CommandText = CommandText;              try              {                  o = mCmd.ExecuteScalar();              }              catch (Exception ex)              {                  logger.Error(ex.ToString());              }              finally              {                  setIsUser( false );              }              return o;          }          public MySqlDataReader ExecuteReader( string CommandText)          {              setIsUser( true );              MySqlDataReader mySqlDataReader = null ;              mCmd.CommandText = CommandText;              try              {                  mySqlDataReader  = mCmd.ExecuteReader();                  //mConn.Close();              }              catch (Exception ex)              {                  logger.Error(ex.ToString());              }              finally              {                  setIsUser( false );              }              return mySqlDataReader;          }          public ConnectionState getState() {              return mConn.State;          }          public bool IsUrse() {              return isUser;          }      } }

2.3.4

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using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace 数据库链接状态确认 {      /// <summary>      /// 单件构象基类      /// </summary>      /// <typeparam name="T"></typeparam>      public class Singleton<T> where T : new ()      {          static T t = default (T);          public static T getMy()          {              if (t == null )              {                  t = new T();              }              return t;          }      } }

运行结果：可用看出是几个链接对象在被循环的使用，也基本达到了直接的初衷，用尽可能少的链接，完成多线程的调用情景。

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id2 index:5 isuser:True setuser:False index:5 isuser:False setuser:True index:5 isuser:True setuser:False get:3 id3 index:5 isuser:False setuser:True get:4 id4 index:5 isuser:True setuser:False index:5 isuser:False setuser:True get:2 id2 index:5 isuser:True setuser:False index:5 isuser:False setuser:True get:3 id3

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原文链接：https://blog.csdn.net/xie__jin__cheng/article/details/127104414