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>