MyBatis source analysis of stored procedure calls and running processes _java

Let's learn about the use and running process of the mybatis call stored procedure. Let's first create a simple stored procedure

DELIMITER $ 
CREATE PROCEDURE mybatis.ges_user_count (in Age INT, out User_count int) 
BEGIN 
SELECT count (*) From the users WHERE users.age=age into User_count; 
End 

The meaning of this stored procedure is simply to enter the age, and then execute SELECT COUNT (*) from the users where users.age = User_count, and the number of people who are equal to ages is assigned to User_count , or relatively simple.

Next is the call to the stored procedure that completes the call to the stored procedure by executing the following command.

Let's take a look at using MyBatis to invoke the stored procedure.

Usermapper.xml Add stored procedure call configuration:

<select id= "Count" statementtype= "callable" parametermap= "Getusercountmap" > Call 
  mybatis.ges_user_count ( ?,?) 

Main function:

public class Learn1main {public 
 static void main (string [] args) { 
  //mybatis configuration file 
  string resource = ' learn/my Batis-config.xml "; 
  Load the MyBatis configuration file with the class loader (it also loads the associated mapping file) 
  InputStream is = Learn1Main.class.getClassLoader (). getResourceAsStream ( Resource); 
  Building sqlsession Factory 
  sqlsessionfactory sessionfactory = new Sqlsessionfactorybuilder (). Build (IS); 
  sqlsession session = Sessionfactory.opensession (); 
  map<string, integer> parametermap = new hashmap<string, integer> (); 
  Parametermap.put ("Age",); 
  Parametermap.put ("User_count",-1); 
  Session.selectone ("Com.tianjunwei.learn.learn1.entity.User.count", parametermap); 
  Integer result = Parametermap.get ("User_count"); 
  SYSTEM.OUT.PRINTLN (result); 
 } 

Run Result:

Its final execution in Defaultresultsethandler, there is a difference between calling ordinary SQL and stored procedures, and the execution of SQL statements is using CallableStatement.

HANDLE output PARAMETER///Call the stored procedure returns the result, placing the result value in the parameter @Override public void Handleoutputparameters (callablestateme 
 NT CS) throws SQLException {final Object parameterobject = Parameterhandler.getparameterobject (); 
 Final MetaObject Metaparam = Configuration.newmetaobject (Parameterobject); 
Final list<parametermapping> parametermappings = Boundsql.getparametermappings (); /loop process each parameter for (int i = 0; i < parametermappings.size (); i++) {final parametermapping parametermapping = parameterm 
 Appings.get (i); 
  To determine the mode of the parameter if (parametermapping.getmode () = = Parametermode.out | | parametermapping.getmode () = = Parametermode.inout) { if (ResultSet.class.equals (Parametermapping.getjavatype ())) {Handlerefcursoroutputparameter (ResultSet) 
  Cs.getobject (i + 1), parametermapping, Metaparam); 
  else {final typehandler<?> Typehandler = Parametermapping.gettypehandler (); 
  Metaparam.setvalue (Parametermapping.getproperty (), Typehandler.getresult (CS, i + 1)); 
 }}} private void Handlerefcursoroutputparameter (ResultSet rs, parametermapping parametermapping, MetaObject Metapara 
 m) throws SQLException {try {final String resultmapid = Parametermapping.getresultmapid (); 
 Final Resultmap Resultmap = Configuration.getresultmap (resultmapid); 
 Final Defaultresulthandler Resulthandler = new Defaultresulthandler (objectfactory); 
 Final Resultsetwrapper RSW = new Resultsetwrapper (rs, configuration); 
 Handlerowvalues (RSW, Resultmap, Resulthandler, New rowbounds (), NULL); 
 Metaparam.setvalue (Parametermapping.getproperty (), resulthandler.getresultlist ()); 
 Finally {//issue #228 (Close resultsets) Closeresultset (RS);  } 
}

The above is a small series to introduce the MyBatis source analysis of the stored procedure call and run the process, I hope to help you, if you have any questions please give me a message, small series will promptly reply to everyone. Here also thank you very much for the cloud Habitat Community website support!