ClassPathXmlApplicationContext

參考文獻：
http://www.blogjava.net/xcp/archive/2011/06/22/352821.html
http://bbs.csdn.net/topics/350033127

一、Spring中ClassPathXmlApplicationContext類的簡單使用

1、簡單的用ApplicationContext做測試的話,獲得Spring中定義的Bean實例(對象).可以用:
ApplicationContext ac = new ClassPathXmlApplicationContext(“applicationContext.xml”);
RegisterDAO registerDAO = (RegisterDAO)ac.getBean(“RegisterDAO”);

如果是兩個以上:
ApplicationContext ac = new ClassPathXmlApplicationContext(new String[]{“applicationContext.xml”,”dao.xml”});

或者用通配符:
ApplicationContext ac = new ClassPathXmlApplicationContext(“classpath:/*.xml”);

2、ClassPathXmlApplicationContext[只能讀放在web-info/classes目錄下的配置文件]和FileSystemXmlApplicationContext的區別

classpath:前綴是不需要的,默認就是指項目的classpath路徑下面;
如果要使用絕對路徑,需要加上file:前綴表示這是絕對路徑;

對於FileSystemXmlApplicationContext:
默認表示的是兩種:

1.沒有盤符的是項目工作路徑,即項目的根目錄;
2.有盤符表示的是文件絕對路徑.

如果要使用classpath路徑,需要前綴classpath:

public class HelloClient {

protected static final Log log = LogFactory.getLog(HelloClient.class);

public static void main(String[] args) {
// Resource resource = new ClassPathResource(“appcontext.xml”);
// BeanFactory factory = new XmlBeanFactory(resource);

// 用classpath路徑
// ApplicationContext factory = new ClassPathXmlApplicationContext("classpath:appcontext.xml");
// ApplicationContext factory = new ClassPathXmlApplicationContext("appcontext.xml");

// ClassPathXmlApplicationContext使用了file前綴是可以使用絕對路徑的
// ApplicationContext factory = new ClassPathXmlApplicationContext("file:F:/workspace/example/src/appcontext.xml");

// 用文件系統的路徑,默認指項目的根路徑
// ApplicationContext factory = new FileSystemXmlApplicationContext("src/appcontext.xml");
// ApplicationContext factory = new FileSystemXmlApplicationContext("webRoot/WEB-INF/appcontext.xml");


// 使用了classpath:前綴,這樣,FileSystemXmlApplicationContext也能夠讀取classpath下的相對路徑
// ApplicationContext factory = new FileSystemXmlApplicationContext("classpath:appcontext.xml");
// ApplicationContext factory = new FileSystemXmlApplicationContext("file:F:/workspace/example/src/appcontext.xml");

// 不加file前綴
ApplicationContext factory = new FileSystemXmlApplicationContext("F:/workspace/example/src/appcontext.xml");
IHelloWorld hw = (IHelloWorld)factory.getBean("helloworldbean");
log.info(hw.getContent("luoshifei"));

}
}

二、場景錯誤：
java.lang.NoClassDefFoundError: org/springframework/expression/PropertyAccessor
at org.springframework.context.support.AbstractApplicationContext.prepareBeanFactory(AbstractApplicationContext.java:483)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:400)
at org.springframework.context.support.ClassPathXmlApplicationContext.

解決辦法：將Spring包全部引入