一、使用org.apache.commons.configuration

需要使用的是jar包：commons-collections-3.2.1.jar、commons-configuration-1.10.jar、commons-lang-2.6.jar和commons-logging-1.2.jar。

可以讀取的配置檔案：xml和properties

1、讀取xml檔案

<span style="font-family:Microsoft YaHei;font-size:12px;">package com.styspace;

import org.apache.commons.configuration.Configuration;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.XMLConfiguration;
public class xmlLoaderTest {

    public static void main(String[] args) throws ConfigurationException{
       Configuration config = new XMLConfiguration("com/styspace/config.xml");
       String name = config.getString("Account.name");
       System.out.println("name:" + name);
    }
}
</span>
 

使用到的config.xml內容如下：

<span style="font-family:Microsoft YaHei;font-size:12px;"><?xml version="1.0" encoding="gbk"?>       
<Accounts> 
	<Account type="by0003">  
		<code>100001</code> 
		<pass>123</pass> 
		<name>李四</name>  
		<money>1000000.00</money>  
	</Account>  
</Accounts></span>
 

2、讀取properties檔案

<span style="font-family:Microsoft YaHei;font-size:12px;">package com.styspace;

import org.apache.commons.configuration.Configuration;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.PropertiesConfiguration;

public class peropertiesLoaderTest {

    public static void main(String[] args) throws ConfigurationException{
       Configuration config = new PropertiesConfiguration("com/styspace/config.properties");
       String name = config.getString("name");
       System.out.println("name:" + name);
    }
}
</span>
 

<span style="font-family:Microsoft YaHei;font-size:12px;">threads.max=50threas.min=2
timout=15.52
interactive=true
color=red
speed=50
name=Default User</span>

二、使用java.util.Properties讀取

<span style="font-family:Microsoft YaHei;font-size:12px;">package com.styspace;

import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

public class PropertiesTest {
	public static void main(String[] args){
		PropertiesTest pt = new PropertiesTest();
		try {
			pt.getProperties();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	
	private void getProperties() throws IOException {
		InputStream inputStream = this.getClass().getClassLoader().getResourceAsStream("com/styspace/config.properties");
		System.out.println("begin!!!");
		Properties properties = new Properties();
		try{
			properties.load(inputStream);
		}catch (IOException ioE){
			ioE.printStackTrace();
		}finally{
			inputStream.close();
		}
		System.out.println("name:"+properties.getProperty("name"));
	}
}
</span>

ClassLoader()和URLClassLoader()區別：ClassLoader()只能查詢src目錄下的檔案，而URLClassLoader()則能查詢任意目錄下的檔案。

三、spring中配置檔案的讀取

1、ClassPathXmlApplicationContext:從類路徑中載入。

2、FileSystemXmlApplicationContext:從檔案系統載入。

3、XmlWebApplicationContext:從web系統中載入。

1、使用bean工廠獲取bean

<span style="font-family:Microsoft YaHei;font-size:12px;">	BeanFactory factory = null; //宣告
	
	ClassPathResource resource = new ClassPathResource("spring.xml");//類路徑
	factory= new XmlBeanFactory(resource); 
	
	FileSystemResource fileSystemResource = new FileSystemResource("D:\\Ncode\\mcode\\sday02\\src\\spring.xml");//檔案路徑
	factory= new XmlBeanFactory(fileSystemResource); 
	
	//XmlBeanFactory(引數可以是resource或者fileSystemResource等
	//但是不能是 res 原因可以檢視：文件Part III. Core Technologies 6. Resources
	//中6.2 The Resource interface 有關isOpen方法的說明);
	//InputStreamResource res = new InputStreamResource(new FileInputStream("D:\\Ncode\\mcode\\sday02\\src\\spring.xml"));//系統路徑

	HelloService helloService = factory.getBean("helloServiceImpl", HelloServiceImpl.class);
	helloService.sayHello();</span>

上下文更加高階：提供文字資訊解析工具，包括對國際化支援；提供載入檔案資源的通用方法，如圖片；可以向註冊為監聽器的bean傳送事件。

 在很少的情況下，使用BeanFactory。

<span style="font-family:Microsoft YaHei;font-size:12px;">	//從檔案系統
	ApplicationContext context = new FileSystemXmlApplicationContext("file:D:\\Ncode\\mcode\\sday02\\src\\spring.xml");
	//從類路徑
	ApplicationContext context = new ClassPathXmlApplicationContext("classpath:spring.xml");
	
	HelloService helloService =  context.getBean("helloServiceImpl", HelloServiceImpl.class);
	helloService.sayHello();</span>

3.1、使用XmlWebApplicationContext

	XmlWebApplicationContext context = new XmlWebApplicationContext(); 
	//預設的路徑/WEB-INF/applicationContext.xml
	//applicationContext.xml檔名稱 可以任意起
	//重新設定路徑
	//context.setConfigLocations(new String[] {"/WEB-INF/classes/applicationContext.xml"}); 
	//設定ServletContext上下下文為web應用程式的上下文
	context.setServletContext(getServletContext());
	//重新整理
	context.refresh();
	//根據id名稱獲取
	HelloDao helloDao = context.getBean("helloDaoImpl", HelloDaoImpl.class);
	//執行helloDao物件的方法
	helloDao.sayHello();

	//直接採用getWebApplicationContext(getServletContext()) 獲取context物件
	WebApplicationContext  context= 
	WebApplicationContextUtils.getWebApplicationContext(getServletContext());
	//context = WebApplicationContextUtils.getRequiredWebApplicationContext(getServletContext());
	System.out.println(context);
	HelloDao helloDao = context.getBean("helloDaoImpl", HelloDaoImpl.class);
	helloDao.sayHello()

1、當採用getWebApplicationContext(getServletContext())獲取context物件的時候，輸出的context物件為null  所以在使用

context.getBean("helloDaoImpl", HelloDaoImpl.class);會出現空指標的異常

   2、當採用getRequiredWebApplicationContext(getServletContext());獲取context物件的時候 會出現如下bug

java.lang.IllegalStateException: No WebApplicationContext found: no ContextLoaderListener registered