Java 系列之spring学习--注解

Posted 2020-10-25 WangJunZzz

一、注解

　　使用注解之前要开启自动扫描功能

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/mvc 
       http://www.springframework.org/schema/mvc/spring-mvc.xsd 
       http://www.springframework.org/schema/context 
       http://www.springframework.org/schema/context/spring-context.xsd 
       http://www.springframework.org/schema/aop 
       http://www.springframework.org/schema/aop/spring-aop.xsd 
       http://www.springframework.org/schema/tx 
       http://www.springframework.org/schema/tx/spring-tx.xsd
       ">
   
  <context:component-scan base-package="SpringAnnotationBll,SpringAnnotationDal" />
</beans>

二、结构代码

　　　　

三、常用注解

　　　　@Service用于标注业务层组件、 
　　　　@Controller用于标注控制层组件（如struts中的action）
　　　　@Repository用于标注数据访问组件，即DAO组件。
　　　　@Component泛指组件，当组件不好归类的时候，我们可以使用这个注解进行标注。
　　　　@Scope用于指定scope作用域的（用在类上）

四、实例

　　4.1、dao层代码

package SpringAnnotationDal;

public interface SpringAnnotationDal {

	public abstract void add();

}

package SpringAnnotationDal;

import org.springframework.stereotype.Repository;

@Repository
public class SpringAnnotationDalBean implements SpringAnnotationDal {

	/* (non-Javadoc)
	 * @see SpringAnnotationDal.SpringAnnotationDal#add()
	 */
	public void add()
	{
		System.out.print("add...");
	}
}　

　　4.2、service层代码

package SpringAnnotationBll;

public interface SpringAnnotationBll {

	public abstract void add();

}

package SpringAnnotationBll;

import org.springframework.stereotype.Service;

import SpringAnnotationDal.SpringAnnotationDal;
@Service
public class SpringAnnotaionBllBean implements SpringAnnotationBll {

	private SpringAnnotationDal springAnnotationDal;
	public SpringAnnotationDal getSpringAnnotationDal() {
		return springAnnotationDal;
	}
	public void setSpringAnnotationDal(SpringAnnotationDal springAnnotationDal) {
		this.springAnnotationDal = springAnnotationDal;
	}
	public void add()
	{
		System.out.print("add...");
	}
}

　　4.3、调用

package test;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import SpringAnnotationBll.SpringAnnotationBll;
import spring.testServiceBean;

public class cservlet extends HttpServlet {


	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		ApplicationContext context=new ClassPathXmlApplicationContext("applicationContext.xml");
		SpringAnnotationBll services=(SpringAnnotationBll)context.getBean("springAnnotaionBllBean");
		services.add();
	}

}　

五、结果