详解Spring 两种注入的方式（Set和构造）实例

package com.xiami.spring; 
 
public class HelloWorld { 
 
  private String str; 
 
  /** 
   * 默认构造方法 
   */ 
  public HelloWorld() { 
  } 
 
  /** 
   * 用来进行构造注入的构造方法 
   * 
   * @param str 
   */ 
  public HelloWorld(String str) { 
    this.str = str; 
  } 
 
  /** 
   * 用来进行Set注入的方法 
   * @param str 
   */ 
  public void setStr(String str) { 
    this.str = str; 
  } 
 
  /** 
   * 输出字符串的方法 
   */ 
  public void sayHello() { 
    System.out.println(str); 
  } 
} 

package com.xiami.spring; 
 
import org.springframework.beans.factory.BeanFactory; 
import org.springframework.beans.factory.xml.XmlBeanFactory; 
import org.springframework.core.io.ClassPathResource; 
 
public class Test { 
 
  /** 
   * @param args 
   */ 
  public static void main(String[] args) { 
    // TODO Auto-generated method stub 
    //载入spring配置文件 
    BeanFactory bFactory = new XmlBeanFactory(new ClassPathResource("applicationContext.xml")); 
    HelloWorld helloWorld = (HelloWorld) bFactory.getBean("helloService"); 
    helloWorld.sayHello(); 
  } 
 
} 

<?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:p="http://www.springframework.org/schema/p" 
  xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd"> 
 
   
  <!-- 使用Set方式注入 --> 
  <!--  
  <span style="color:#ff0000;"><bean id="helloService" class="com.xiami.spring.HelloWorld" 
    abstract="false" lazy-init="default" autowire="default"> 
    <property name="str"> 
      <value type="java.lang.String">hello world</value> 
    </property> 
  </bean></span> 
   --> 
    
   <!-- 使用构造方法方式注入  
   <bean id="helloService" class="com.xiami.spring.HelloWorld" 
    abstract="false" lazy-init="default" autowire="default"> 
    <constructor-arg> 
      <value type="java.lang.String">构造方法注入方式</value> 
    </constructor-arg> 
   </bean> 
   --> 
    
   </beans>