A supplement to spring's first example

1. First import the required packages:

2. File structure:

3. Look at the XML configuration file first:

<?XML version= "1.0" encoding= "UTF-8"?><!DOCTYPE Beans Public "-//spring//dtd BEAN 2.0//en" "Http://www.springframework.org/dtd/spring-beans-2.0.dtd" ><Beans>    <!--let spring manage the creation and dependency of objects, which must be defined in the spring configuration file -    <!--Configure the beans that need to be managed by spring (created and placed inside the spring IOC container) -    <Beanname= "Hello"class= "Com.wangcf.HelloWorld">        <!--Configure the attributes that the bean needs to inject (it is injected by the Set method) -        < Propertyname= "Name"value= "Direct"/>    </Bean>        <Beanname= "Userdao"class= "Com.wangcf.Dao.UserDao"></Bean>    <Beanname= "Usermanager"class= "Com.wangcf.UserManager">        <!--injected with the value of DAO, value is injected constant value, ref injection reference value -        < Propertyname= "Userdao"ref= "Userdao"></ Property>    </Bean></Beans>

4.1 See HelloWorld section:

 PackageCOM.WANGCF; Public classHelloWorld {PrivateString name;  PublicHelloWorld () {System.out.println (The HelloWorld constructor starts to create ... "); }     Public voidsetName (String name) {System.out.println ("SetName. Inject the value of name into .... ");  This. Name =name; }         Public voidShow () {System.out.println ("Holloworld show ..." +name); }        }

 Packagecom.wangcf.Test;Importorg.springframework.beans.factory.BeanFactory;ImportOrg.springframework.context.support.ClassPathXmlApplicationContext;ImportCom.wangcf.HelloWorld;Importjunit.framework.TestCase; Public classHolloworldtestextendstestcase{ Public voidtest1 () {//get spring's applicationcontext configuration file into the IOC containerBeanfactory factory=NewClasspathxmlapplicationcontext ("Applicationcontext.xml"); /**complete the above steps and you will print: The *helloworld constructor starts to create ...        *setname. * Note that the properties of the class are injected from the beginning.*/        //get beans from the IOC container through the Beanfactory Getbean methodObject Obj=factory.getbean ("Hello");        System.out.println (Obj.getclass (). GetName ()); HelloWorld HW=(HelloWorld) obj;        SYSTEM.OUT.PRINTLN (HW);        Hw.show (); //get beans from the IOC container through the Beanfactory Getbean methodHelloWorld hw2= (HelloWorld) factory.getbean ("Hello");    System.out.println (HW2); }}

Print:

This shows that in implementing

Beanfactory factory=New classpathxmlapplicationcontext ("Applicationcontext.xml");

, the contents of the configuration file are executed.

5.1 See Usermanager section:

 PackageCOM.WANGCF;ImportCom.wangcf.Dao.UserDao; Public classUsermanager {PrivateUserdao Userdao; //inject DAO with the Set method, which is not a constant value, but a reference value     Public voidSetuserdao (Userdao Userdao) {System.out.println ("Usermanager Userdao Setuserdao. Inject DAO into the Usermanager container ");  This. Userdao =Userdao; }         Public voidAddUser () {System.out.println ("Usermanager AddUser");    Userdao.adduser (); }         PublicUsermanager () {System.out.println ("Usermanager start creating ...."); }}

 Package Com.wangcf.Dao;  Public class Userdao {     publicvoid  AddUser () {         System.out.println ("Userdao addUser" );     }            Public Userdao () {         System.out.println ("Userdao start creating ...");}     }

 Packagecom.wangcf.Test;Importjunit.framework.TestCase;Importorg.springframework.beans.factory.BeanFactory;ImportOrg.springframework.context.support.ClassPathXmlApplicationContext;ImportCom.wangcf.UserManager; Public classUsermanagertestextendstestcase{ Public voidTestadduser () {Beanfactory factory=NewClasspathxmlapplicationcontext ("Applicationcontext.xml"); Usermanager Usermanager= (Usermanager) factory.getbean ("Usermanager"); System.out.println ("------------");    Usermanager.adduser (); }}

Print

Summary:

The properties of the Usermanager class and the HelloWorld class are injected through dependency.

The instantiation of an object is a dependency injection, so you don't have to use new one every time?

A supplement to spring's first example