模擬Spring讀取Properties文件
轉自：http://www.cnblogs.com/shamgod/p/4586971.html
一、目標：讀取配置文件properties文件，獲得類名來生成對象
二、類
1.Movable.java
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public interface Movable
{ void run();} |
2.Car.java
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public class Car implements Movable
{ public void run()
{ System.out.println("Car
running..............."); } } |
3.spring.properties
PS:"="兩邊不能有空格
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vechileType=com.tong.spring.factory.Car |
4.Test.java
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public class Test
{ @org.junit.Test public void test()
{ //讀取properties文件，獲得類名來生成對象 Properties
pros = new Properties(); try { //1.讀取要實例化的類名 pros.load(Test.class.getClassLoader().getResourceAsStream("com/tong/spring/factory/spring.properties")); String
vechileType = pros.getProperty("vechileType"); //2.利用反射裝載類及用newInstance()實例化類 Object
o = Class.forName(vechileType).newInstance(); Movable
m = (Movable)o; m.run(); } catch (Exception
e) { e.printStackTrace(); } }} |
5.運行結果：
6.若改成spring讀取xml文件，則spring配置好後，增加applicationContext.xml
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<?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改爲如下
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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模擬Spring
轉自：http://www.cnblogs.com/shamgod/p/4587387.html
一、概述
1.目標：模擬Spring的Ioc
2.用到的知識點：利用jdom的xpath讀取xml文件，反射
二、有如下文件：
1.applicationContext.xml
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<?xml
version="1.0" encoding="UTF-8"?><beans> <bean
id="vehicle" class="com.tong.spring.factory.Car"> </bean></beans> |
2.BeanFactory.java
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public interface BeanFactory
{ Object
getBean(String id);} |
3.ClassPathXmlApplicationContext.java
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public class ClassPathXmlApplicationContext implements BeanFactory{ private Map<String,
Object> container = new HashMap<String,
Object>(); public ClassPathXmlApplicationContext(String
fileName) { //讀取xml文件 SAXBuilder
sb = new SAXBuilder(); Document
doc; try { //doc
= sb.build(fileName); //Test.java要改爲BeanFactory
factory = new ClassPathXmlApplicationContext("com/tong/spring/factory/applicationContext.xml"); //否則付出現“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,然後裝進容器 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
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public interface Movable
{ void run();} |
5.Car.java
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public class Car implements Movable
{ public void run()
{ System.out.println("Car
running..............."); } } |
6.Test.java
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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(); }} |
運行結果：
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<Element> expr = xFactory.compile("//link", Filters.element());
List<Element> 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<Element> 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());
}
}
