spring

简单spring实例
第一步：下载spring.jar，commons-logging.jar包。并导入工程
         导入步骤：右击工程--》Build Path--》Add External Archiyes...

第二步：工程中新建三个java文件

文件一：

package com.springination.chapter01.hello;

public interface IGreetingService {
	public void sayGreeting();

}

文件二：

package com.springination.chapter01.hello;

public class GreetingServiceImpl implements IGreetingService {

	private String greeting;
	public GreetingServiceImpl(){}
	public GreetingServiceImpl(String greeting){
		this.greeting = greeting;
	}
	public void sayGreeting(){
		System.out.println(greeting);
	}
	public void setGreeting(String greeting) {
		this.greeting = greeting;
	}

}

文件三：

package com.springination.chapter01.hello;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.FileSystemResource;
import org.springframework.core.io.Resource;

public class Helloworld {

	/**
	 * @param args
	 */
	public static void main(String[] args) 
	{
		//方法一  FileSystemResource类，默认xml文件的路径在工程目录下
		Resource resource =  new FileSystemResource("hello.xml");
		BeanFactory factory = new XmlBeanFactory(resource);
		GreetingServiceImpl greetingService = (GreetingServiceImpl) factory.getBean("greetingService");
		greetingService.sayGreeting();
		
		//方法二 ClassPathXmlApplicationContext类，默认的寻找xml文件的路径就在src目录下
//		ApplicationContext ac = new ClassPathXmlApplicationContext("hello.xml");
//		GreetingServiceImpl greetingService = (GreetingServiceImpl) ac.getBean("greetingService");
//		greetingService.sayGreeting();
		
		//方法三 FileSystemXmlApplicationContext类，默认的寻找xml文件的路径就在src目录下
//		ApplicationContext ac = new FileSystemXmlApplicationContext("hello.xml");
//		GreetingServiceImpl greetingService = (GreetingServiceImpl) ac.getBean("greetingService");
//		greetingService.sayGreeting();
	}

}

第三步：新建hello.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN"
 	"http://www.springframework.org/dtd/spring-beans.dtd">
<beans>
	<bean id="greetingService"
	 	class="com.springination.chapter01.hello.GreetingServiceImpl">
		<property name="greeting">
			<value>hello world</value>
		</property>
	</bean> 	
</beans>

hello.xml文件的具体存放位置，要看在第二步中helloworld.java文件用到的获取xml文件里的类。上面列举了三种。都有存放位置的注释。

遇到的问题一：

Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory

原因，没导入commons-logging.jar包

问题二：

Caused by: java.io.FileNotFoundException: hello.xml (系统找不到指定的文件。)

hello.xml文件的存放位置不正确：具体见第二步中文件三里的注释。