Architecture analysis of three-tier project and parameter name injection of construction method

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Architecture analysis of three-tier project

  Not Spring Take over the three-tier project construction :

spring Take over the creation of three-tier objects  

Use the constructor parameter name to inject values  

   Use the parameter name of the construction method to inject values

Use the subscript of the construction method parameter to inject the value

Assign values using the default parameters of the constructor

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Architecture analysis of three-tier project

Use three-tier architecture to insert users
Interface layer , Business logic layer , Data access layer ( simulation )

Spring Will take over the creation of which objects in the three-tier architecture ? Interface layer objects , Business logic layer objects , Data access layer objects .

  Not Spring Take over the three-tier project construction :

  Entity class
  com.bjpowernode.pojo  Users
  Data access layer
  com.bjpowernode.dao   UsersMapper.java( Interface )
                          UsersMapperImpl.java( Implementation class )
  Business logic layer
  com.bjpowernode.service   UsersService.java( Interface )
                              UsersServiceImpl.java( Implementation class )
  Interface layer
  com.bjpowernode.controller  UsersController.java

Next, we will continue to build a framework

 

 

  Then create a new entity class

 

Inside the entity class set、get Methods should be added ！（Alt+Insert） 

 

 

 

spring Take over the creation of three-tier objects  

Logical objects of the data access layer

  Business logic layer

  Interface layer

  The last step is to test

The three steps of the test should be clear ！ A certain ！

Use the constructor parameter name to inject values  

 
  Use the parameter name of the construction method to inject values

 
    Student stu = new Student(" Zhang San ",22);
a. Use the parameter name of the construction method to inject values 
            <bean id="school" class="com.bjpowernode.pojo3.School">
                <constructor-arg name="name1" value=" Tsinghua University "></constructor-arg>
                <constructor-arg name="address1" value=" Haidian District "></constructor-arg>
            </bean>
      
       c. Inject values in the order of the parameters of the default construction method 
               <bean id="stuSequence" class="com.bjpowernode.pojo3.Student">
                <constructor-arg value=" Chen Shi "></constructor-arg>
                <constructor-arg value="22"></constructor-arg>
                <constructor-arg ref="school"></constructor-arg>
            </bean>

 

Then let's test

  The name of the constructor is used as the injection value

Use the subscript of the construction method parameter to inject the value

 b. Use the subscript injection value of the construction method parameter 
             <bean id="stu" class="com.bjpowernode.pojo3.Student">
                <constructor-arg index="0" value=" Qian Qi "></constructor-arg>
                <constructor-arg index="1" value="22"></constructor-arg>
                <constructor-arg index="2" ref="school"></constructor-arg>
            </bean>

 

 

 

Assign values using the default parameters of the constructor