关于Spring中ApplicationContext的说明

关于Spring中ApplicationContext的说明

一、简单的用ApplicationContext做测试的话,获得Spring中定义的Bean实例(对象).可以用:

ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");RegisterDAO registerDAO = (RegisterDAO)ac.getBean("RegisterDAO");

如果是两个以上:

ApplicationContext ac = new ClassPathXmlApplicationContext(new String[]{"applicationContext.xml","dao.xml"});

或者用通配符:

ApplicationContext ac = new ClassPathXmlApplicationContext("classpath:/*.xml");

二、ClassPathXmlApplicationContext[只能读放在web-info/classes目录下的配置文件]和FileSystemXmlApplicationContext的区别
classpath:前缀是不需要的,默认就是指项目的classpath路径下面;
如果要使用绝对路径,需要加上file:前缀表示这是绝对路径;
对于FileSystemXmlApplicationContext:
默认表示的是两种:
1.没有盘符的是项目工作路径,即项目的根目录;
2.有盘符表示的是文件绝对路径.
如果要使用classpath路径,需要前缀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路径ApplicationContext factory = new ClassPathXmlApplicationContext("classpath:appcontext.xml");ApplicationContext factory = new ClassPathXmlApplicationContext("appcontext.xml");// ClassPathXmlApplicationContext使用了file前缀是可以使用绝对路径的ApplicationContext factory = new ClassPathXmlApplicationContext("file:F:/workspace/example/src/appcontext.xml");// 用文件系统的路径,默认指项目的根路径ApplicationContext factory = new FileSystemXmlApplicationContext("src/appcontext.xml");ApplicationContext factory = new FileSystemXmlApplicationContext("webRoot/WEB-INF/appcontext.xml");// 使用了classpath:前缀,这样,FileSystemXmlApplicationContext也能够读取classpath下的相对路径ApplicationContext factory = new FileSystemXmlApplicationContext("classpath:appcontext.xml");ApplicationContext factory = new FileSystemXmlApplicationContext("file:F:/workspace/example/src/appcontext.xml");// 不加file前缀ApplicationContext factory = new FileSystemXmlApplicationContext("F:/workspace/example/src/appcontext.xml");IHelloWorld hw = (IHelloWorld)factory.getBean("helloworldbean");log.info(hw.getContent("luoshifei"));}}