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package shangbo.spring.example28;public interface MessageService {	String getMessage();}

package shangbo.spring.example28;public class MessageServiceImpl implements MessageService {	public String getMessage() {		return "Hello World";	}}

package shangbo.spring.example28;public class MessagePrinter {    final private MessageService service;    public MessagePrinter(MessageService service) {        this.service = service;    }    public void printMessage() {        System.out.println(this.service.getMessage());    }}

package shangbo.spring.example28;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class App {	public static void main(String[] args) {		// 实例化 Spring IoC 容器		ApplicationContext context = new ClassPathXmlApplicationContext("example.xml", MessagePrinter.class);				// 从容器中获得 MessagePrinter 的实例		MessagePrinter printer = context.getBean(MessagePrinter.class);				// 使用对象		printer.printMessage();	}}

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