Programming of the Di mating interface in spring

One: di basic concept

Dependency Injection (DI), which is the foundation of the spring container implementation, is implemented in the Spring-core module. The so-called Di, refers to the object is passively accept the dependency class rather than take the initiative to find, in other words, the object is not from the container to find the class it depends on, but when the container instantiation of the object, it is actively to inject its dependent classes to it.

Di effect:

The Di Mate interface programming does reduce the coupling between the layer (Web layer) and the business layer.

Two: Di mating interface Programming case

1. Project

2. Basic code

Package com.cloud.inter;

Public Interface Changeletter {

Public String change ();

}

Package com.cloud.inter;

Public class Lowerletter Implements changeletter{

Private Stringstr;

Public String Getstr () {

return str;

}

Public void setstr (String str) {

this. str = str;

}

@Override

Public String Change () {

// TODO auto-generated Method Stub

return str. toLowerCase ();

}

}

Package com.cloud.inter;

Public class Upperletter Implements changeletter{

Private Stringstr;

Public String Getstr () {

return str;

}

Public void setstr (String str) {

this. str = str;

}

@Override

Public String Change () {

// TODO auto-generated Method Stub

return str. toUpperCase ();

}

}

3. Configure the Code

<? XML version="1.0"encoding="Utf-8"?>

< Beans xmlns="Http://www.springframework.org/schema/beans"

xmlns:xsi="Http://www.w3.org/2001/XMLSchema-instance"

Xmlns:context="Http://www.springframework.org/schema/context"

xmlns:tx="Http://www.springframework.org/schema/tx"

xsi:schemalocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/ Schema/beans/spring-beans-2.5.xsd

Http://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context-2.5.xsd

http://www.springframework.org/schema/txhttp://www.springframework.org/schema/tx/spring-tx-2.5.xsd " >

<!-- switch between the two configuration methods in the test code -

<!--

<beanid= "Changeletter" class= "Com.cloud.inter.UpperLetter" >

<propertyname= "str" >

<value>ABCEF</value>

</property>

</bean>

-

< Bean id="Changeletter"class="Com.cloud.inter.LowerLetter">

< Property name="str"value="ABCDE"/>

</ Bean >

</ Beans >

4. Test code

Package com.cloud.inter;

Importorg.springframework.context.ApplicationContext;

Importorg.springframework.context.support.ClassPathXmlApplicationContext;

public class App1 {

/**

* @param args

*/

publicstatic void Main (string[] args) {

TODO auto-generated Method Stub

Applicationcontextac=new classpathxmlapplicationcontext ("Com/cloud/inter/beans.xml");

Get not using interfaces

Upperletterchangeletter= (Upperletter) Ac.getbean ("Changeletter");

System.out.println (Changeletter.change ());

accessing beans using interfaces

Changeletterchangeletter= (Changeletter) Ac.getbean ("Changeletter");

System.out.println (Changeletter.change ());

}

}

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Programming of the Di mating interface in spring