ParameterType usage of the mapper configuration file for MyBatis

The ParameterType attribute is mentioned in the MyBatis Select, INSERT, UPDATE, delete elements . MyBatis can now be used for parametertype with basic data types and Java complex data types

• Basic data type: Contains Int,string,date and so on. The base data type is passed as a parameter and can only pass in one. The passed value can be obtained by #{the parameter name}
• Complex data types: Contains Java entity classes, maps. By #{property name} or

• #{map KeyName} to get the value passed in

• Examples of basic data type parameters:

Query teacher list based on class ID

XML file

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1. < Select id="selectteacher" parametertype="int"   resulttype = "Com.myapp.domain.Teacher" >
2. SELECT * from Teacher where c_id=#{id}
3. </ Select >   

Java code

[Java]View Plaincopy

1. list<teacher> tList = Teachermapper.selectteacher (2);
2. for (Teacher entitytemp:tlist) {
3. System.out.println (Entitytemp.tostring ());
4. }

• Examples of Java entity type Parameters :

[HTML]View Plaincopy

1. < Select id="selectteacher" parametertype=" Com.myapp.domain.Teacher " resulttype=" Com.myapp.domain.Teacher " >
2. SELECT * from Teacher where c_id=#{id}
3. </ Select >   

[Java]View Plaincopy

1. Java code
3. Teacher queryteacher=New Teacher ();
4. Queryteacher.setid (2);
5. list<teacher> tList = Teachermapper.selectteacher (Queryteacher);
6. for (Teacher entitytemp:tlist) {
7. System.out.println (Entitytemp.tostring ()); }

• Example Map parameters:
  [HTML]View Plaincopy
  1. < Select id="selectteacher" parametertype="Map"   resulttype = "Com.myapp.domain.Teacher" >
  2. SELECT * from Teacher where c_id=#{id} and sex=#{sex}
  3. </ Select >   
  
  [Java]View Plaincopy
  1. java code   
  2.    
  3. map<string,string> map=new  HasMap<String,String> ();   
  4. map.put ( , );   
  5. map.put ( "sex" , "male" );   
  6. list<teacher> tlist  = teachermapper.selectteacher (map);     
  7. for   (teacher entitytemp : tlist)  {    
  8.     system.out.println (entitytemp.tostring ()); }   

 In addition, MyBatis provides a way to use annotations to enter multiple parameters. This approach requires adding @param annotations on the interface's parameters

Example:

Interface method

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1. Public list<teacher> selectteacher (@Param(value="id") String ID, @Param  (value="Sex") String sex);

XML file

[HTML]View Plaincopy

1. < Select id="selectteacher" resulttype=" Com.myapp.domain.Teacher ">
2. SELECT * from Teacher where c_id=#{id} and sex=#{sex}
3. </ Select >   

Test code

[Java]View Plaincopy

1. list<teacher> tList = teachermapper.selectteacher ("2","male");
2. for (Teacher entitytemp:tlist) {
3. System.out.println (Entitytemp.tostring ());

ParameterType usage of the mapper configuration file for MyBatis