@Repository 、@Service、@Controller案例详解

web开发，提供3个@Component注解衍生注解（功能一样）取代
@Repository ：dao层
@Service：service层
@Controller：web层

套路是这样的，service层调动dao层，web层调动service层，展示出来

下面就是案例演示了

dao层代码：

package com.fly.spring.annotation;import org.springframework.stereotype.Repository;@Repository("sudentDao")public class SudentDao {    public void save(){        System.out.println("dao层");    }}

service层代码：

package com.fly.spring.annotation;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.beans.factory.annotation.Qualifier;import org.springframework.stereotype.Service;@Servicepublic class PersonService {    private SudentDao sudentDao;    @Autowired    @Qualifier("sudentDao")   // 按照名称注入    public void setSudentDao(SudentDao sudentDao){        this.sudentDao = sudentDao;    }    // 给web层调用的方法    public void getString(){        sudentDao.save();    }}

web层代码：

package com.fly.spring.annotation;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;@Controller("teacherWeb")public class TeacherWeb {    @Autowired //默认按照类型    private PersonService person;    public void execute(){        person.getString();    }}

配置文件代码applicationContext.xml：

<?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/context                            http://www.springframework.org/schema/context/spring-context.xsd">    <!-- 组件扫描，扫描含有注解的类 -->    <context:component-scan base-package="com.fly.spring.annotation"></context:component-scan></beans>

测试代码：

package com.fly.spring.annotation;import org.junit.Test;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class TestDemo {    @Test    public void demo(){        String xmlpath = "com/fly/spring/annotation/applicationContext.xml";        ApplicationContext context = new ClassPathXmlApplicationContext(xmlpath);        TeacherWeb bean = (TeacherWeb) context.getBean("teacherWeb");        bean.execute();    }}

测试结果：

2017-3-2 10:14:04 org.springframework.context.support.AbstractApplicationContext prepareRefresh信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@1b016632: startup date [Thu Mar 02 10:14:04 CST 2017]; root of context hierarchy2017-3-2 10:14:04 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions信息: Loading XML bean definitions from class path resource [com/fly/spring/annotation/applicationContext.xml]2017-3-2 10:14:06 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons信息: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@43ee148b: defining beans [personService,sudentDao,teacherWeb,org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor]; root of factory hierarchydao层