这篇文章给大家分享的是有关Spring中xml配置的示例分析的内容。小编觉得挺实用的,因此分享给大家做个参考,一起跟随小编过来看看吧。
1、一个Performer接口:
package springAction;
public interface Performer {
void perform();
}
2、一个Juggler类实现了Performer接口:
package springAction;
public class Juggler implements Performer{
private int beanBags = 3;
public Juggler(){
}
public Juggler(int beanBags){
this.beanBags = beanBags;
}
public void perform(){
System.out.println("Juggling " + beanBags + " beanbags");
}
}
3、一个 PoeticJuggler类继承了Juggler类:
package springAction;
public class PoeticJuggler extends Juggler {
private Poem poem;
public PoeticJuggler(Poem poem){
super();
this.poem = poem;
}
public PoeticJuggler(int beanBags, Poem poem){
super(beanBags);
this.poem = poem;
}
public void perform(){
super.perform();
System.out.println("PoeticJugger reciting...");
poem.recite();
}
}
4、一个Poem接口:
package springAction;
public interface Poem {
void recite();
}
5、一个单例类Stage:
package springAction;
public class Stage {
private Stage(){
}
private static class StageSingletonHolder{
static Stage instance = new Stage();
}
public static Stage getInstance(){
return StageSingletonHolder.instance;
}
}
6、看看xml文件怎么写(springAction.xml):
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-4.1.xsd">
<!-- 配置一个bean -->
<bean id="duke" class="springAction.Juggler" >
<!--给构造函数传递参数,没有的话则调用默认构造方法 -->
<constructor-arg value="15"/>
</bean>
<bean id="sonnet29" class="springAction.Sonnet29"></bean>
<bean id="poeticDuke" class="springAction.PoeticJuggler">
<constructor-arg value="22"></constructor-arg>
<!-- 基本数据类型参数用value=字符串(Spring根据构造参数类型自动解析字符串),
引用类型的参数用ref= bean id -->
<constructor-arg ref="sonnet29"></constructor-arg>
</bean>
<!-- factory-method通过工厂方法将单例类配置为bean,因为Stage没有构造函数 -->
<bean id="theStage" class="springAction.Stage" factory-method="getInstance">
</bean>
</beans>
加个main函数运行一下,看看效果:
package springAction;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class springActionMain {
public static void main(String[] args) {
// TODO Auto-generated method stub
ApplicationContext ctx = new ClassPathXmlApplicationContext(
"springAction/springAction.xml");
try{
Performer performer = (Performer)ctx.getBean("duke");
performer.perform();
performer = (Performer)ctx.getBean("poeticDuke");
performer.perform();
}catch(Exception e){
e.printStackTrace();
}finally{
((ClassPathXmlApplicationContext)ctx).close();
}
}
}
7、bean的作用域
所有的Spring Bean默认是单例,当容器分配一个Bean时,它总是返回同一个实例。但,spring是灵活的,不需要单例模式时,可以如下配置:
<bean id="ticket" class="省略号" scope="prototype"/>
8、初始化Bean和销毁Bean
当Spring容器实例化一个Bean时可能需要做一些初始化的工作,当Spring销毁一个Bean时,可能需要做一些清理工作。Spring支持Bean提供自定义的方法来做初始化工作和销毁工作。
9、为Bean注入属性
一般地,java Bean会有一些私有属性,并有一些set和get方法。Spring可以利用set方法为bean的私有属性注入值。
例子:
package springAction;
public class Instrumentalist implements Performer{
private String song;
private Instrument instrument;
private int age;
public Instrumentalist(){
}
public void perform(){
System.out.println("age = " + age);
System.out.println("Playing "+song);
instrument.play();
}
public String getSong() {
return song;
}
public void setSong(String song) {
this.song = song;
}
public Instrument getInstrument() {
return instrument;
}
public void setInstrument(Instrument instrument) {
this.instrument = instrument;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
xml文件配置:
<bean id="saxophone" class="springAction.Saxophone"/>
<bean id="kenny" class="springAction.Instrumentalist">
<!-- 配置属性song -->
<property name="song" value="ABC"></property>
<!-- 配置属性age,虽然此处是字符串“14”,但是Spring会识别age的类型,然后把字符串“14”转变后赋值给age -->
<property name="age" value="14"></property>
<!-- 配置instrument对象,用ref的方式赋引用,和构造函数一致 -->
<property name="instrument" ref="saxophone"></property>
</bean>
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