"Spring Combat"--5 set Value injection

This article explains the most common features of spring-dependency injection.

The way to inject is to use Getter setter injection, usually most of the programming is also used this method.

To give a simple example, or a performer.

Performers have their own attributes, age or performances of the song and so on. It also requires complex properties, such as musical instruments, that each instrument makes a different sound.

Here's a look at the performer performer

Package Com.spring.test.action1;  Public Interface Performer {    void  perform () throws performanceexception;}

We define ourselves as a piano performer who has age and song, and an additional instrument attribute.

Package Com.spring.test.setter;import Com.spring.test.action1.performanceexception;import Com.spring.test.action1.Performer; Public classinstrumentalist implements performer{PrivateString Song; Private intAge ; Privateinstrument instrument;  Public intGetage () {returnAge ; }     Public voidSetage (intAge ) {         This. Age =Age ; }     PublicString Getsong () {returnSong; }     Public voidSetsong (String song) { This. Song =Song; }     PublicInstrument getinstrument () {returninstrument; }     Public voidSetinstrument (instrument instrument) { This. Instrument =instrument; }     Publicinstrumentalist () {} Public voidperform () throws Performanceexception {System. out. println ("instrumentalist Age:"+Age ); System. out. Print ("Playing"+song+":");    Instrument.play (); }}

The instrument is constructed as follows, still using the interface method:

Package Com.spring.test.setter;  Public Interface Instrument {    publicvoid  play ();}

SAX implements the Instrument interface

Package Com.spring.test.setter;  Public class Saxophone implements instrument {    public  saxophone () {}    publicvoid  Play () {        System. out. println ("Toot Toot toot");     }

The above is the construction of the basic class.

Here's a look at spring's configuration file:

<?xml version="1.0"encoding="UTF-8"? ><beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns="Http://www.springframework.org/schema/beans"xsi:schemalocation="Http://www.springframework.org/schema/beanshttp//www.springframework.org/schema/beans/spring-beans-3.0.xsd "><bean id="Sax" class="Com.spring.test.setter.Saxophone"/> <bean id="Kenny" class="com.spring.test.setter.Instrumentalist"> <property name="Song"Value="Jingle Bells"/> <property name=" Age"Value=" -"/> <property name="Instrument" ref="Sax"/> </bean></beans>

In the configuration file, you can find that when setting a value injection, use name to specify which property to inject .

Name is named in terms of the variable name.

1 letters are not case-sensitive and the other parts are the same as variable names.

2 Injected property type, can be string, int, double, float, etc., when the property is a string or int, it can be automatically converted according to the type of the variable.

3 is injected with a bean, it is directly linked to another bean using ref.

Here is the code for the application context:

Package Com.spring.test.setter;import Org.springframework.context.applicationcontext;import Org.springframework.context.support.classpathxmlapplicationcontext;import com.spring.test.action1.PerformanceException; Public classTest { Public Static voidMain (string[] args) throws performanceexception {ApplicationContext ctx=NewClasspathxmlapplicationcontext ("Bean.xml"); Instrumentalist performer= (instrumentalist) Ctx.getbean ("Kenny");    Performer.perform (); }}

The results of the implementation are as follows:

Instrumentalist Age:Playing jingle Bells:toot Toot Toot

"Spring Combat"--5 set Value injection