多线程访问数据库(当多用户同时访问时会出现数据异常)

多线程访问数据库(当多用户同时访问时会出现数据错误)
action类:  
public   class   CheckAction  
{  
        private   CheckDAO   checkDAO   =   new   CheckDAO();  

        public   CheckDAO   getCheckDAO()  
      {  
              return   checkDAO;  
        }  

        public   void   setCheckDAO(CheckDAO   checkDAO)  
      {  
            this.checkDAO   =   checkDAO;  
        }  

public   String   update()  
{  
checkDAO.update();  
return   "update ";  
}  
}  

DAO类:  
public   class   CheckDAO  
{  
private   Connection   conn   =   null;  
private   String   sql   =   " ";  
private   ResultSet   rSet   =   null;  

//将数据插入到TABLE1,然后获自增的ID，再更新TABLE2,当只有一个用户操作时数据正确，多用户并发数据就不正确了  
public   void   update()  
{  
try  
{  
conn   =   JdbcUtils.getConnection();
sql= "INSERT   INTO   TABLE1   (NAME,PASSWORD)   VALUES   ( 'NAME1 ', 'NAME1 ') ";  
conn.prepareStatement(sql).executeUpdate();  

sql   =   "SELECT   IDENT_CURRENT( 'TABLE1 ')   NewId ";  
rSet   =   conn.prepareStatement(sql).executeQuery();  
rSet.next();  

sql= "UPDATE   TABLE2   SET   table1_id=rSet.getString( "NewId "),   IsDone= 'Y ' ";  
conn.prepareStatement(sql).executeUpdate();  
}  
finally  
{  
JdbcUtils.free(rSet,null,conn);  
}  
}  
}  

数据库连接:  
public   class   JdbcUtils  
{  
private   static   DataSource   myDataSource   =   null;  

private   JdbcUtils()  
{  
}  

static  
{  
try  
{  
Properties   prop   =   new   Properties();  
InputStream   is   =   JdbcUtils.class.getClassLoader()  
.getResourceAsStream( "dbcpconfig.properties ");  
prop.load(is);  
myDataSource   =   BasicDataSourceFactory.createDataSource(prop);  
}  
catch   (Exception   e)  
{  
throw   new   ExceptionInInitializerError(e);  
}  
}  

public   static   Connection   getConnection()   throws   SQLException  
{  
//   return   DriverManager.getConnection(url,   user,   password);  
return   myDataSource.getConnection();  

}  

public   static   void   free(ResultSet   rs,   Statement   st,   Connection   conn)  
{  
try  
{  
if   (rs   !=   null)  
rs.close();  
}  
catch   (SQLException   e)  
{  
e.printStackTrace();  
}  
finally  
{  

try  
{  
if   (st   !=   null)  
st.close();  
}  
catch   (SQLException   e)  
{  
e.printStackTrace();  
}  
finally  
{  
if   (conn   !=   null)  
{  
try  
{  
conn.close();  
//myDataSource.free(conn);  
}  
//   catch   (SQLException   e)  
catch   (Exception   e)  
{  
e.printStackTrace();  
}  
}  
}  
}  
}  

}  

struts.xml:  
<?xml   version= "1.0 "   encoding= "UTF-8 "?>  
<!DOCTYPE   struts   PUBLIC   "-//Apache   Software   Foundation//DTD   Struts   Configuration   2.1//EN "  
                "http://struts.apache.org/dtds/struts-2.1.dtd ">  

<struts>  
<package   name= "default "   namespace= "/ "   extends= "json-default ">  
        <action>  
<result   name= "update "> </result>                                    
</action>  
</package>  
</struts>  


[解决办法]
数据不同步了吧
[解决办法]

Java code

action类:   public   class   CheckAction   {           private   CheckDAO   checkDAO   =   new   CheckDAO();           public   CheckDAO   getCheckDAO()         {                 return   checkDAO;           }           public   void   setCheckDAO(CheckDAO   checkDAO)         {               this.checkDAO   =   checkDAO;           }   public   String   update()   {   checkDAO.update();   return   "update ";   }   }   DAO类:   public   class   CheckDAO   {   private   Connection   conn   =   null;   private   String   sql   =   " ";   private   ResultSet   rSet   =   null;   //将数据插入到TABLE1,然后获自增的ID，再更新TABLE2,当只有一个用户操作时数据正确，多用户并发数据就不正确了   public   void   update()   {   try   {   conn   =   JdbcUtils.getConnection(); sql= "INSERT   INTO   TABLE1   (NAME,PASSWORD)   VALUES   ( 'NAME1 ', 'NAME1 ') ";   conn.prepareStatement(sql).executeUpdate();   sql   =   "SELECT   IDENT_CURRENT( 'TABLE1 ')   NewId ";   rSet   =   conn.prepareStatement(sql).executeQuery();   rSet.next();   sql= "UPDATE   TABLE2   SET   table1_id=rSet.getString( "NewId "),   IsDone= 'Y ' ";   conn.prepareStatement(sql).executeUpdate();   }   finally   {   JdbcUtils.free(rSet,null,conn);   }   }   }   数据库连接:   public   class   JdbcUtils   {   private   static   DataSource   myDataSource   =   null;   private   JdbcUtils()   {   }   static   {   try   {   Properties   prop   =   new   Properties();   InputStream   is   =   JdbcUtils.class.getClassLoader()   .getResourceAsStream( "dbcpconfig.properties ");   prop.load(is);   myDataSource   =   BasicDataSourceFactory.createDataSource(prop);   }   catch   (Exception   e)   {   throw   new   ExceptionInInitializerError(e);   }   }   public   static   Connection   getConnection()   throws   SQLException   {   //   return   DriverManager.getConnection(url,   user,   password);   return   myDataSource.getConnection();   }   public   static   void   free(ResultSet   rs,   Statement   st,   Connection   conn)   {   try   {   if   (rs   !=   null)   rs.close();   }   catch   (SQLException   e)   {   e.printStackTrace();   }   finally   {   try   {   if   (st   !=   null)   st.close();   }   catch   (SQLException   e)   {   e.printStackTrace();   }   finally   {   if   (conn   !=   null)   {   try   {   conn.close();   //myDataSource.free(conn);   }   //   catch   (SQLException   e)   catch   (Exception   e)   {   e.printStackTrace();   }   }   }   }   }   }   struts.xml:   <?xml   version= "1.0 "   encoding= "UTF-8 "?>   <!DOCTYPE   struts   PUBLIC   "-//Apache   Software   Foundation//DTD   Struts   Configuration   2.1//EN "                   "http://struts.apache.org/dtds/struts-2.1.dtd ">   <struts>   <package   name= "default "   namespace= "/ "   extends= "json-default ">           <action>   <result   name= "update "> </result>                                     </action>   </package>   </struts>