spring裝配bean(基於註解)

spring裝配bean(基於註解)

裝配bean(基於註解)

l  註解:就是一個類,使用@註解名稱

l  開發中:使用註解 取代 xml配置檔案。

 

l  註解使用前提,新增名稱空間,讓spring掃描含有註解類

1. @Component

@Component取代<bean class=””>

@Component(“id”)取代 <beanid=”” class=””>

UserService:

package com.itheima.g_annotation.a_ioc;
public interface UserService {
public void addUser();
}

UserServiceImpl:

package com.itheima.g_annotation.a_ioc;
import org.springframework.stereotype.Component;
@Component("userServiceId")
public class UserServiceImpl implements UserService {
@Override
public void addUser() {
System.out.println("g_annotation.a_ioc add user");
}
}

beans.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">
<!-- 元件掃描,掃描含有註解的類 -->
<context:component-scan base-package="com.itheima.g_annotation.a_ioc"></context:component-scan>
</beans>

TestAnnoIoC:

package com.itheima.g_annotation.a_ioc;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestAnnoIoC {
@Test
public void demo02(){
//從spring容器獲得
String xmlPath = "com/itheima/g_annotation/a_ioc/beans.xml";
ApplicationContext applicationContext = new ClassPathXmlApplicationContext(xmlPath);
UserService userService = (UserService) applicationContext.getBean("userServiceId");
userService.addUser();
}
}

2.web開發

提供3個@Component註解衍生註解(功能一樣)取代<beanclass=””>

       @Repository:dao層

       @Service:service層

       @Controller:web層

3.依賴注入    

給私有欄位設定,也可以給setter方法設定

       普通值:@Value(“”)

       引用值:

              方式1:按照【型別】注入

                     @Autowired

              方式2:按照【名稱】注入1

                     @Autowired

                     @Qualifier(“名稱”)

              方式3:按照【名稱】注入2

                     @Resource(“名稱”)

StudentDao:

package com.itheima.g_annotation.b_web;
public interface StudentDao {
void save();
}

StudentDaoImpl:

package com.itheima.g_annotation.b_web;
import org.springframework.stereotype.Repository;
@Repository("studentDaoId")
public class StudentDaoImpl implements StudentDao {
@Override
public void save() {
System.out.println("dao");
}
}

StudentService:

package com.itheima.g_annotation.b_web;
public interface StudentService {
void addStudent();
}

StudentServiceImpl:

package com.itheima.g_annotation.b_web;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;
@Service
public class StudentServiceImpl implements StudentService {
private StudentDao studentDao;
@Autowired
@Qualifier("studentDaoId")
public void setStudentDao(StudentDao studentDao) {
this.studentDao = studentDao;
}
@Override
public void addStudent() {
studentDao.save();
}
}

StudentAction:

package com.itheima.g_annotation.b_web;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
@Controller("studentActionId")
public class StudentAction {
@Autowired //預設按照型別
private StudentService studentService;
public void execute() {
studentService.addStudent();
}
}

beans.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">
<!-- 元件掃描,掃描含有註解的類 -->
<context:component-scan base-package="com.itheima.g_annotation.b_web"></context:component-scan>
</beans>

TestAnnoWeb:

package com.itheima.g_annotation.b_web;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestAnnoWeb {
@Test
public void demo02(){
//從spring容器獲得
String xmlPath = "com/itheima/g_annotation/b_web/beans.xml";
ApplicationContext applicationContext = new ClassPathXmlApplicationContext(xmlPath);
StudentAction studentAction = (StudentAction) applicationContext.getBean("studentActionId");
studentAction.execute();
}
}

4.生命週期

       初始化:@PostConstruct

       銷燬:@PreDestroy

5.作用域

       @Scope(“prototype”)多例

UserService:

package com.itheima.g_annotation.c_other;
public interface UserService {
public void addUser();
}

UserServiceImpl:

package com.itheima.g_annotation.c_other;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Service;
@Service("userServiceId")
//@Scope("prototype")
public class UserServiceImpl implements UserService {
@Override
public void addUser() {
System.out.println("d_scope add user");
}
@PostConstruct
public void myInit(){
System.out.println("初始化");
}
@PreDestroy
public void myDestroy(){
System.out.println("銷燬");
}
}

beans.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">
<!-- 元件掃描,掃描含有註解的類 -->
<context:component-scan base-package="com.itheima.g_annotation.c_other"></context:component-scan>
</beans>

TestOther:

package com.itheima.g_annotation.c_other;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class TestOther {
@Test
public void demo02(){
//spring 工廠
String xmlPath = "com/itheima/g_annotation/c_other/beans.xml";
ClassPathXmlApplicationContext applicationContext = new ClassPathXmlApplicationContext(xmlPath);
UserService userService = applicationContext.getBean("userServiceId" ,UserService.class);
UserService userService2 = applicationContext.getBean("userServiceId" ,UserService.class);
System.out.println(userService);
System.out.println(userService2);
applicationContext.close();
}
}