spring加载之FileSystemXmlApplicationContext与ClassPathXmlApplicationContext的区别

约定不等于承诺〃 2021-09-24 03:24 554阅读 0赞

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");

ClassPathXmlApplicationContext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");
    
        // 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"));
      }
    }