【spring bean】bean的配置和创建方式

1 package com.it.sxd;
2 
3 public interface SayHell {
4         public void sayHello();
5 }

 1 package com.it.sxd;
 2 
 3 public class SayHelloImpl implements SayHell {
 4 
 5     @Override
 6     public void sayHello() {
 7         System.out.println("hello");
 8     }
 9 
10 }

 1 package com.it.sxd;
 2 
 3 public class SayHelloImpl2 implements SayHell {
 4     private String message;
 5 
 6     public SayHelloImpl2() {
 7         this.message = "无参的构造器";
 8     }
 9     
10     public SayHelloImpl2(String message) {
11         super();
12         this.message = message;
13     }
14 
15     @Override
16     public void sayHello() {
17         System.out.println(message);
18     }
19     
20 }

 1 package com.it.sxd;
 2 
 3 public class SayHelloFactory {
 4     
 5     public static SayHell  sayhell(String message){
 6         return new SayHelloImpl2(message);
 7     }
 8     
 9     public  static void  sayAmount(){
10         double b= 9/3;
11         System.out.println(b);
12     }
13     
14 }

 1 <?xml version="1.0" encoding="UTF-8"?>  
 2 <beans  
 3 xmlns="http://www.springframework.org/schema/beans"  
 4 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
 5 xmlns:context="http://www.springframework.org/schema/context"  
 6 xsi:schemaLocation="  
 7 http://www.springframework.org/schema/beans        http://www.springframework.org/schema/beans/spring-beans-3.0.xsd  
 8 http://www.springframework.org/schema/context                http://www.springframework.org/schema/context/spring-context-3.0.xsd">  
 9 
10 
11      <!--测试1 ：bean就是Ioc容器初始化。装配，管理的对象，除此之外，bean与应用程序中的对象没有任何区别， id 表示你这个组件的名字，class表示组件类，也就是位置 -->  
12     <bean id="hello1" class="com.it.sxd.SayHelloImpl">
13     </bean>  
14     
15     <!--测试2 无参的构造方法  使用标签alisa起别名   -->
16     <bean id="hello3" class="com.it.sxd.SayHelloImpl2">    
17     </bean>
18     <alias name="hello3" alias="alisa3"/>
19     
20     <!-- 测试2  有参数的构造方法  使用name，给多个值起别名-->
21     <bean id="hello2" name="alisa1,alisa2" class="com.it.sxd.SayHelloImpl2">
22         <constructor-arg index="0" value="hello有参构造方法"></constructor-arg><!-- 默认的为构造方法传值，index代表第几个参数，0代表第一个，value就是给构造器传递的值 -->
23     </bean>
24     
25     <!-- 测试3  静态工厂创建bean factory-method就代表初始化这个class类的时候，就执行了这个类中的"sayhell"方法，并且要求这个方法必须是static -->
26     <bean id="hello4" class="com.it.sxd.SayHelloFactory"  factory-method="sayhell">
27         <constructor-arg type="java.lang.String" value="静态工厂创建bean"></constructor-arg><!-- 为这个sayhell方法传递参数，参数类型是String类型，值是value -->
28     </bean>
29     
30     <!-- 测试3  静态工厂创建bean ，init-method初始化执行的方法 -->
31     <bean id="hello5" class="com.it.sxd.SayHelloFactory" init-method="sayAmount">
32     </bean>
33     
34     
35     
36 </beans>  

 1 package com.it.sxd;
 2 
 3 
 4 import org.junit.Test;
 5 import org.springframework.context.ApplicationContext;
 6 import org.springframework.context.support.ClassPathXmlApplicationContext;
 7 import org.springframework.context.support.FileSystemXmlApplicationContext;
 8 
 9 public class SayHelloTest {
10 
11     @Test
12     public void testSayHello(){
13         //System.out.println(SayHelloTest.class.getResource(""));
14         //1.读取hello。xml配置文件，实例化一个Ioc容器
15         ApplicationContext context = new FileSystemXmlApplicationContext("resources/hello.xml");
16         //2.从Ioc容器中获取ID为"hello1"的bean ,此处是“面向接口编程   而不是面向实现编程”
17         SayHell sayHell = context.getBean("hello1",SayHell.class);
18         //3.实现功能
19         sayHell.sayHello();
20     }    
21 
22 }

 1 package com.it.sxd;
 2 
 3 import org.junit.Test;
 4 import org.springframework.context.ApplicationContext;
 5 import org.springframework.context.support.FileSystemXmlApplicationContext;
 6 
 7 public class SayHelloTest2 {
 8 
 9     @Test
10     public  void testSayHello() {
11         ApplicationContext context = new FileSystemXmlApplicationContext("resources/hello.xml");
12         SayHell syahell = context.getBean("hello2",SayHell.class);//getBean()方法传进来两个参数  参数1：配置文件中bean的id   参数2：SayHell.class就是这个bean返回的结果强转为SayHell类型的
13         syahell.sayHello();
14         
15         SayHell sayhell2 = (SayHell) context.getBean("alisa3");//如果geyBean()方法不传进来第二个参数，那就需要自己进行强转
16         sayhell2.sayHello();
17         
18         String [] attr = context.getAliases("hello2");//getAliases() 获取id为hello2的bean的别名
19         for (String string : attr) {
20             System.out.println(string);
21         }
22     }
23 
24 }

 1 package com.it.sxd;
 2 
 3 import org.junit.Test;
 4 import org.springframework.context.ApplicationContext;
 5 import org.springframework.context.support.FileSystemXmlApplicationContext;
 6 
 7 public class SayHelloTest3 {
 8     @Test
 9     public void sayHello(){
10         //1。通过加载配置文件来实例化一个Ioc容器，
11         ApplicationContext context = new FileSystemXmlApplicationContext("resources/hello.xml");
12         //2.从Ioc容器得到对应的bean
13         SayHell sayhell = context.getBean("hello4",SayHell.class);
14         //3.执行bean的方法
15         sayhell.sayHello();
16         
17         
18         SayHelloFactory sa = (SayHelloFactory) context.getBean("hello5");
19         
20         
21     }
22 }