标签：base spring注解 des 依赖注入 gets struct lap 注解 tco
1、注解
注解就是一个类，使用@加上注解名称，开发中可以使用注解取代配置文件
2、@Component 取代<bean class="">,@Component 取代<bean id="" class="">
（1）创建一个类（该类与dao层无联系，是一个单独的类）
@Component("studentService")
public class StudentServiceImpl implements StudentService {
public void addStudent(){
System.out.println("StudentService的实现类的Add方法！！");
}
}
（2）创建配置文件：
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns="http://www.springframework.org/schema/beans" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <context:component-scan base-package="pers.zhb.service"></context:component-scan> </beans>
（3）测试类：
public class TestCycle { public static void main(String[] args) { ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");//创建容器对象 StudentService studentService= (StudentService) applicationContext.getBean("studentService"); studentService.addStudent(); } }
（4）web开发中，提供了3个@Component注解的衍生注解（功能一样）
@Repository：dao层
@Service：service层
@Controller：web层
3、依赖注入
（1）创建一个Action：
@Controller("studentAction")
public class StudentAction {
@Autowired//默认按照类型注入
private StudentService studentService;
public void execute(){
studentService.addStudent();
}
}
（2）service层：
public interface StudentService { public void addStudent(); }
@Service public class StudentServiceImpl implements StudentService { private StudentDao studentDao; @Qualifier("studentDao") public StudentDao getStudentDao() { return studentDao; } @Autowired public void setStudentDao(StudentDao studentDao) { this.studentDao = studentDao; } public void addStudent(){ studentDao.addStudent(); } }
（3）dao层：
public interface StudentDao { public void addStudent(); }
@Repository("studentDao")
public class StudentDaoImpl implements StudentDao {
@Override
public void addStudent() {
System.out.println("StudentDao的实现类的Add方法！！");
}
}
（4）配置文件：
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns="http://www.springframework.org/schema/beans" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <!--扫描--> <context:component-scan base-package="pers.zhb"></context:component-scan> </beans>
（5）测试：
public class ActionTest { public static void main(String[] args) { ApplicationContext applicationContext=new ClassPathXmlApplicationContext("applicationContext.xml");//创建容器对象 StudentAction studentAction= (StudentAction) applicationContext.getBean("studentAction"); studentAction.execute(); } }
StudentDao的实现类的Add方法！！
4、生命周期
初始化：@PostConstruct
销毁：@PreDestory
分别添加到初始化和销毁方法之前。
5、作用域
多例：@Scope("prototype")
标签：base spring注解 des 依赖注入 gets struct lap 注解 tco
原文地址：https://www.cnblogs.com/zhai1997/p/12696197.html
