MyBatis a series of problems (a workaround that traverses the map collection and smart tags and attributes and fields)

What if the field name is different from the property name (the name of the database)? Scenario One: Configure a resultmapper in a small configuration

<!-- -

     <Resultmaptype= "Student"ID= "Studentmapper">        <resultcolumn= "Stuname2" Property= "Stuname"/>    </Resultmap>    <!--Query All - <SelectID= "FindAll"Resultmap= "Studentmapper">SELECT * FROM Student</Select>

Scenario Two: Query statements in small configurations with AS

<!---<id= "FindAll"  Resulttype  = "Student">      Select Stuname2 as Stuname from Student    </  Select>

Second, mapper dynamic agent culling implementation class The first step of the change is the small configuration of <mapper namespace= "Cn.happy.dao.IStudentDAO" > Write to the interface

<?xml version="1.0"encoding="UTF-8"? ><!DOCTYPE mapperpublic"-//mybatis.org//dtd Mapper 3.0//en""HTTP://MYBATIS.ORG/DTD/MYBATIS-3-MAPPER.DTD"><mappernamespace="Cn.happy.dao.IStudentDAO"> <!--Scenario Two: As aliases---<SelectId="FindAll"Resulttype="Student">SelectStuname2 asStuname fromStudent</Select></mapper>

The second step is to use Getmapper to get an interface implementation class when the test class invokes the interface.

 Public classMyTest {Istudentdao dao; @Before Public voidInitData ()throwsioexception{sqlsession Session=mybatisutil.getsession (); //Dynamic kick Out implementation class//first change studentdao.xml to <mapper namespace= "Cn.happy.dao.IStudentDAO" >Dao=session.getmapper (Istudentdao.class); }        /*** SelectAll Students *@throwsIOException*/@Test Public voidFindAll ()throwsioexception{List<Student> list =Dao.findall ();  for(Student student:list) {System.out.println (Student.getstuname ()); /*System.out.println (Student.getstuage ());*/        }            }    }

Third, using the map set value and use index number (a) using the map collection to get the value 1 customizing a method on the interface Istudentdao

// Multi-conditional query encapsulation into map    Public List<student> Findstudentmore (map<string, object> Map);

2 id= "Findstudentmore" in a small configuration to be the same as the method of the interface Dharma name

<!--multi-condition query--><SelectId="Findstudentmore"Resulttype="Student"> <!--mysql database--<!--Select* fromStudentwhereStuname like'%'#{stuname}'%'and Stuage>#{stuage}-<!--ORCL Database--Select* fromStudentwhereStuname like'%'|| #{stuname}| |'%'and stuage>#{stuage}</Select>

3 in the test class

/*** Multi-criteria Query *@throwsIOException*/@Test Public voidFindstudentmore () {Map<string, object> maplist=NewHashmap<string, object>(); Maplist.put ("Stuname", "123"); Maplist.put ("Stuage", 11); List<Student> list =Dao.findstudentmore (maplist);  for(Student student:list) {System.out.println (Student.getstuname ()); }            }

(ii) using index 1 to customize a method on the interface Istudentdao

// multi-Conditional query quotes    Public List<student> findstudentbycondition (String name,int age);

2 in a small configurationid= "Findstudentmore" to be the same way as the interface Dharma name

<SelectId="findstudentbycondition"Resulttype="Student"> <!--MySQL DatabaseSelect* fromStudentwhereStuname like'%'#{0}'%'and stuage>#{1} ORCL Database-Select* fromStudentwhereStuname like'%'|| #{0}||'%'and stuage>#{1}            </Select>

3 in the test class

@Test      Public void throws ioexception{        String name= "Person";         int age=12;        List<Student> list = dao.findstudentbycondition (name,age);          for (Student student:list) {            System.out.println (Student.getstuname ());        }            }

Small summary:

　　　　　　

Iv. Smart Tags What they used together is the following 1 define a method in the connector

 Public List<student> findstudentbyif (Student stu);

2 Test class

 Public classMyTest {Istudentdao dao; @Before Public voidInitData ()throwsioexception{sqlsession Session=mybatisutil.getsession (); //Dynamic kick Out implementation class//first change studentdao.xml to <mapper namespace= "Cn.happy.dao.IStudentDAO" >Dao=session.getmapper (Istudentdao.class); }                /*** Multi-criteria Query *@throwsIOException*/@Test Public voidFindstudentbycondition ()throwsioexception{String name= "Person"; intAge=12; Student Stu=NewStudent ();        Stu.setstuage (age);        Stu.setstuname (name); List<Student> list =Dao.findstudentbyif (STU);  for(Student student:list) {System.out.println (Student.getstuname ()); }            }    

3 Configuring the If label in a small configuration

<!--multi-condition query-<SelectId="findstudentif"Resulttype="Student">Select* fromStudentwhere 1=1<iftest="Stuname!=null">and Stuname like'%'|| #{stuname}| |'%'</if> <iftest="Stuage!=null">and Stuage>#{stuage}</if> </Select>

where labelNote If you have a <where> tag, you do not need where 1=1

<!--multi-condition query-<SelectId="Findstudentbychoose"Resulttype="Student">Select* fromStudent <!--where 1=1 If you have a where label you don't need-<where> <iftest="Stuname!=null">and Stuname like'%'|| #{stuname}| |'%'</if> <iftest="Stuage!=null">and Stuage>#{stuage}</if> </where> </Select>

Choose Label

<!--multi-criteria query where1=1If you have a where label you don't need-<SelectId="Findstudentbyif"Resulttype="Student">Select* fromStudent<where> <choose> <when test="Stuname!=null">and Stuname like'%'|| #{stuname}| |'%'</when> <otherwise> </otherwise> </choose> </where> </Select>

MyBatis a series of problems (a workaround that traverses the map collection and smart tags and attributes and fields)