模拟Spring读取Properties文件

转自：http://www.cnblogs.com/shamgod/p/4586971.html

一、目标：读取配置文件properties文件，获得类名来生成对象

二、类

1.Movable.java

                         
public
interface
Movable { 
    
void
run();
}
        
      

2.Car.java

                         
public
class
Car 
implements
Movable { 
    
public
void
run() { 
        
System.out.println(
"Car running..............."
);
    
}
    
}
        
      

3.spring.properties

PS:"="两边不能有空格

                         
vechileType=com.tong.spring.factory.Car

4.Test.java

                         
public
class
Test { 
    
    
@org
.junit.Test
    
public
void
test() { 
        
        
//读取properties文件，获得类名来生成对象
        
Properties pros = 
new
Properties();
        
        
try
{ 
            
//1.读取要实例化的类名
            
pros.load(Test.
class
.getClassLoader().getResourceAsStream(
"com/tong/spring/factory/spring.properties"
));
            
String vechileType = pros.getProperty(
"vechileType"
);
            
            
//2.利用反射装载类及用newInstance()实例化类
            
Object o = Class.forName(vechileType).newInstance();
            
Movable m = (Movable)o;
            
m.run();
        
} 
catch
(Exception e) { 
            
e.printStackTrace();
        
}
    
}
}
        
      

5.运行结果：

6.若改成spring读取xml文件，则spring配置好后，增加applicationContext.xml

                         
<?xml version=
"1.0"
encoding=
"UTF-8"
?>
<beans xmlns=
"http://www.springframework.org/schema/beans"
       
xmlns:xsi=
"http://www.w3.org/2001/XMLSchema-instance"
       
xsi:schemaLocation="http:
//www.springframework.org/schema/beans
           
http:
//www.springframework.org/schema/beans/spring-beans-3.0.xsd">
  
<bean id=
"vehicle"
class
=
"com.tong.spring.factory.Car"
>
  
</bean>
  
<!-- more bean definitions go here -->
</beans>
        
      

7.Test.java改为如下

                         
public
class
Test { 
    
    
@org
.junit.Test
    
public
void
test() { 
        
        
BeanFactory factory = 
new
ClassPathXmlApplicationContext(
"applicationContext.xml"
);
        
Object o = factory.getBean(
"vehicle"
);
        
Movable m = (Movable)o;
        
m.run();
    
}
}
        
      

用Jdom模拟Spring

转自：http://www.cnblogs.com/shamgod/p/4587387.html

一、概述

1.目标：模拟Spring的Ioc

2.用到的知识点：利用jdom的xpath读取xml文件，反射

二、有如下文件：

1.applicationContext.xml

                         
<?xml version=
"1.0"
encoding=
"UTF-8"
?>
<beans>
  
<bean id=
"vehicle"
class
=
"com.tong.spring.factory.Car"
>
  
</bean>
</beans>
        
      

2.BeanFactory.java

                         
public
interface
BeanFactory { 
    
Object getBean(String id);
}

3.ClassPathXmlApplicationContext.java

                         
public
class
ClassPathXmlApplicationContext 
implements
BeanFactory{ 
    
    
private
Map<String, Object> container = 
new
HashMap<String, Object>();
    
public
ClassPathXmlApplicationContext(String fileName) { 
        
        
//读取xml文件
        
SAXBuilder sb = 
new
SAXBuilder();
        
Document doc;
        
try
{ 
            
//doc = sb.build(fileName);
            
//Test.java要改为BeanFactory factory = new ClassPathXmlApplicationContext("com/tong/spring/factory/applicationContext.xml");
            
//否则付出现“java.net.MalformedURLException”
            
doc = sb.build(
this
.getClass().getClassLoader().getResourceAsStream(fileName));
            
Element root = doc.getRootElement();
            
List list = XPath.selectNodes(root, 
"/beans/bean"
);
            
for
(
int
i = 
0
; i < list.size(); i++) { 
                
Element element = (Element) list.get(i);
                
String id = element.getAttributeValue(
"id"
);
                
String clazz = element.getAttributeValue(
"class"
);
                
// 利用反射生成例,然后装进容器
                
Object o = Class.forName(clazz).newInstance();
                
container.put(id, o);
            
}
        
} 
catch
(Exception e) { 
            
e.printStackTrace();
        
}
    
}
    
@Override
    
public
Object getBean(String id) { 
        
return
container.get(id);
    
}
}
        
      

4.Movable.java

                         
public
interface
Movable { 
    
void
run();
}
        
      

5.Car.java

                         
public
class
Car 
implements
Movable { 
    
public
void
run() { 
        
System.out.println(
"Car running..............."
);
    
}
    
}
        
      

6.Test.java　

                         
public
class
Test { 
    
    
@org
.junit.Test
    
public
void
test() { 
        
        
//BeanFactory factory = new ClassPathXmlApplicationContext("applicationContext.xml");
        
BeanFactory factory = 
new
ClassPathXmlApplicationContext(
"com/tong/spring/factory/applicationContext.xml"
);
        
Object o = factory.getBean(
"vehicle"
);
        
Movable m = (Movable)o;
        
m.run();
    
}
}
        
      

运行结果：

JDOM 2操作XML：http://www.studytrails.com/java/xml/jdom2/java-xml-jdom2-xpath/

package com.studytrails.xml.jdom;  import java.io.IOException;import java.util.List; import org.jdom2.Document;import org.jdom2.Element;import org.jdom2.JDOMException;import org.jdom2.Namespace;import org.jdom2.filter.Filters;import org.jdom2.input.SAXBuilder;import org.jdom2.xpath.XPathExpression;import org.jdom2.xpath.XPathFactory;  public class XPathExample2 {    private static String xmlSource = "http://feeds.bbci.co.uk/news/technology/rss.xml?edition=int";      public static void main(String[] args) throws JDOMException, IOException {          // read the XML into a JDOM2 document.        SAXBuilder jdomBuilder = new SAXBuilder();        Document jdomDocument = jdomBuilder.build(xmlSource);          // use the default implementation        XPathFactory xFactory = XPathFactory.instance();        // System.out.println(xFactory.getClass());          // select all links        XPathExpression
   
     expr = xFactory.compile("//link", Filters.element());        List
    
      links = expr.evaluate(jdomDocument);        for (Element linkElement : links) {            System.out.println(linkElement.getValue());        }          // select all links in image element        expr = xFactory.compile("//image/link", Filters.element());        List
     
       links2 = expr.evaluate(jdomDocument);        for (Element linkElement : links2) {            System.out.println(linkElement.getValue());        }          // get the media namespace        Namespace media = jdomDocument.getRootElement().getNamespace("media");        // find all thumbnail elements from the media namespace where the        // attribute widht has a value > 60        expr = xFactory.compile("//media:thumbnail[@width>60.00]", Filters.element(), null, media);        // find the first element in the document and get its attribute named 'url'        System.out.println(expr.evaluateFirst(jdomDocument).getAttributeValue("url"));                           // find the child element of channel whose name is title. find the        // descendant of item with name title.        Element firstTitle = xFactory.compile("//channel/child::item/descendant::title", Filters.element()).evaluateFirst(jdomDocument);        System.out.println(firstTitle.getValue());      }  }