感謝：http://blog.chinaunix.net/uid-20681545-id-184633.html提供的解決方案，非常棒 ！
問題說明：
新建一個Spring項目，新建一個Bean類：HelloWorld類，Main.java是主程序，xml是Spring配置文件。
項目結構如下：
打開文件夾，src目錄下的結構如下：
打開bin文件夾，目錄如下
HelloWorld.java代碼：
1 package com.tt.spring.beans; 2 3 public class HelloWorld { 4 5 private String name; 6 7 public void setName(String name) { 8 this.name = name; 9 } 10 11 public void hello(){ 12 System.out.println("hello: "+name); 13 } 14 15 }
Main.java
1 package com.tt.spring.beans; 2 3 import org.springframework.context.ApplicationContext; 4 import org.springframework.context.support.ClassPathXmlApplicationContext; 5 6 public class Main { 7 8 public static void main(String[] args){ 9 /* 10 //創建HelloWorld的一個對象 11 HelloWorld helloWorld = new HelloWorld(); 12 //為name屬性賦值 13 helloWorld.setName("tt"); 14 */ 15 //調用hello方法 16 17 //1.創建Spring 的 IOC 容器對象 18 ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml"); 19 20 //2.從IOC容器中獲取Bean實例 21 HelloWorld helloWorld = (HelloWorld) ctx.getBean("helloWorld"); 22 23 //3.調用Hello方法 24 helloWorld.hello(); 25 26 } 27 }
applicationContext.xml:
1 <?xml version="1.0" encoding="UTF-8"?> 2 <beans xmlns="http://www.springframework.org/schema/beans" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"> 5 6 <!-- 配置bean --> 7 <bean id="helloWorld" class="com.tt.spring.beans.HelloWorld"> 8 <property name="name" value="Spring"></property> 9 </bean> 10 </beans>
運行Main.java程序，結果顯示報錯。報錯如下：
信息: Loading XML bean definitions from class path resource [applicationContext.xml]
Exception in thread "main" org.springframework.beans.factory.BeanDefinitionStoreException: IOException parsing XML document from class path resource [applicationContext.xml]; nested exception is java.io.FileNotFoundException: class path resource [applicationContext.xml] cannot be opened because it does not exist
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:343)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:303)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:180)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:216)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:187)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:251)
at org.springframework.context.support.AbstractXmlApplicationContext.loadBeanDefinitions(AbstractXmlApplicationContext.java:127)
at org.springframework.context.support.AbstractXmlApplicationContext.loadBeanDefinitions(AbstractXmlApplicationContext.java:93)
at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:129)
at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:540)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:454)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
at com.tt.spring.beans.Main.main(Main.java:18)
Caused by: java.io.FileNotFoundException: class path resource [applicationContext.xml] cannot be opened because it does not exist
at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:158)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:329)
... 13 more
問題分析：
1 1 package com.tt.spring.beans; 2 2 3 3 public class Car { 4 4 5 5 private String brand; 6 6 private String corp; 7 7 private int price; 8 8 private int maxSpeed; 9 9 10 10 11 11 public Car() { 12 12 System.out.println("Car's Constructor"); 13 13 } 14 14 15 15 public Car(String brand, String corp, int price) { 16 16 super(); 17 17 this.brand = brand; 18 18 this.corp = corp; 19 19 this.price = price; 20 20 } 21 21 22 22 @Override 23 23 public String toString() { 24 24 return "Car [brand=" + brand + ", corp=" + corp + ", price=" + price + ", maxSpeed=" + maxSpeed + "]"; 25 25 } 26 26 27 27 }
applicationContext.xml
1 <?xml version="1.0" encoding="UTF-8"?> 2 <beans xmlns="http://www.springframework.org/schema/beans" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 xsi:schemaLocation="http://www.springframework.org/schema/beans 5 http://www.springframework.org/schema/beans/spring-beans.xsd"> 6 7 <context:component-scan base-package="com.tt.spring.beans"></context:component-scan> 8 <!-- 9 配置bean 10 class:bean的全類名，通過反射的方式在IOC容器中創建Bean實例，所以要求Bean中必須有無參的構造器 11 id:標識容器中的bean，id唯一 12 --> 13 <bean id="helloWorld" class="com.tt.spring.beans.HelloWorld"> 14 <property name="name" value="Spring"></property> 15 </bean> 16 17 <!-- 通過構造方法來配置bean的屬性 --> 18 <bean id="car" class="com.tt.spring.beans.Car"> 19 <constructor-arg value="Audi"></constructor-arg> 20 <constructor-arg value="chengdu"></constructor-arg> 21 <constructor-arg value="30000"></constructor-arg> 22 </bean> 23 24 </beans>
Main.java
控制台打印信息如下：
看到沒？只能獲取一個bean實例，不能獲取兩個。
原因分析：
在項目里，applicationContext.xml是在src最里面一層的，不在src的那一層，所以一旦運行Main.java文件，相應的就會在bin的目錄下生成對應的applicationContext.xml文件。
但是我們又在bin文件夾里做過粘貼applicationContext.xml。
所以說applicationContext.xml的目錄壓根就是混亂的！！！既是處於根目錄，又處於com最里面的目錄。
要么在項目上將xml移到src那一層，那么bin底下的xml也對應着-------xml就處於根目錄。
要么在項目上仍然位於com的最里面，那么bin那里就不要將xml移出來----xml就處於最里面的目錄
至於xml文件究竟在哪個目錄，就該用相應的讀取方式。
ClassPathXmlApplicationContext和FileSystemXmlApplicationContext讀取xml
ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml")
如果使用FileSystemXmlApplicationContext讀取，則需把配置文件放到整個項目的根目錄