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"));
  }
}

1. FileSystemXmlApplicationContext

pplicationContext ctx = new FileSystemXmlApplicationContext("bean.xml"); //加载单个配置文件

String[] locations = {"bean1.xml", "bean2.xml", "bean3.xml"};
ApplicationContext ctx = new FileSystemXmlApplicationContext(locations ); //加载多个配置文件

ApplicationContext ctx =new FileSystemXmlApplicationContext("D:roject/bean.xml");//根据具体路径加载文件

2. ClassPathXmlApplicationContext

pplicationContext ctx = new ClassPathXmlApplicationContext("bean.xml");

String[] locations = {"bean1.xml", "bean2.xml", "bean3.xml"};
ApplicationContext ctx = new ClassPathXmlApplication(locations);
注：其中FileSystemXmlApplicationContext和ClassPathXmlApplicationContext与BeanFactory的xml文件定位方式一样是基于路径的。

3. XmlWebApplicationContext
ServletContext servletContext = request.getSession().getServletContext();
ApplicationContext ctx = WebApplicationContextUtils.getWebApplicationContext(servletContext);