Spring中IOC的Annotation实现

Spring中IOC的Annotation实现：

此处特别注意每个类中注释的注解及相关文字说明，可以更好的理解Spring中IOC的Annotation实现！

首先beans.xml中需要引入 context 的schema：

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1. <?xml version="1.0" encoding="UTF-8"?>
2. <beans xmlns="http://www.springframework.org/schema/beans"
3. xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
4. xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
5. http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd">

在XML中配置Spring对Annotation的相关配置：

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1. <!-- 打开Spring的Annotation的支持 -->
2. <context:annotation-config />
3. <!-- 设定Spring去哪些包中找Annotation -->
4. <context:component-scan base-package="com.spring" />

完整的XML配置：

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1. <?xml version="1.0" encoding="UTF-8"?>
2. <beans xmlns="http://www.springframework.org/schema/beans"
3. xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
4. xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
5. http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.2.xsd">
6. <!-- 打开Spring的Annotation的支持 -->
7. <context:annotation-config />
8. <!-- 设定Spring去哪些包中找Annotation -->
9. <context:component-scan base-package="com.spring" />
10. </beans>

User实体类：

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1. package com.spring.model;
2. public class User {
3. public User() {
4. super();
5. }
6. private int id;
7. private String username;
8. public int getId() {
9. return id;
10. }
11. public void setId(int id) {
12. this.id = id;
13. }
14. public String getUsername() {
15. return username;
16. }
17. public void setUsername(String username) {
18. this.username = username;
19. }
20. @Override
21. public String toString() {
22. return "User [id=" + id + ", username=" + username + "]";
23. }
24. public User(int id, String username) {
25. super();
26. this.id = id;
27. this.username = username;
28. }
29. }

IUserDao接口:

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1. package com.spring.dao;
2. import com.spring.model.User;
3. public interface IUserDao {
4. public void add(User user);
5. public void delete(int id);
6. public User load(int id);
7. }

UserDao类：

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1. package com.spring.dao;
2. import org.springframework.stereotype.Component;
3. import org.springframework.stereotype.Repository;
4. import com.spring.model.User;
5. //等于完成了<bean id="userDao" class="com.spring.dao.UserDao"/>
6. //@Component("userDao") //@Component公共的创建bean的Annotation
7. @Repository("userDao")  //@Repository表示一般用于Dao的注入
8. public class UserDao implements IUserDao {
9. @Override
10. public void delete(int id) {
11. System.out.println("删除了"+id);
12. }
13. @Override
14. public User load(int id) {
15. System.out.println("load了User");
16. return null;
17. }
18. @Override
19. public void add(User user) {
20. System.out.println("添加了"+user);
21. }
22. }

IUserService接口：

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1. package com.spring.service;
2. import com.spring.model.User;
3. public interface IUserService {
4. public void add(User user);
5. public void delete(int id);
6. public User load(int id);
7. }

UserService类：

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1. package com.spring.service;
2. import javax.annotation.Resource;
3. import org.springframework.stereotype.Component;
4. import org.springframework.stereotype.Service;
5. import com.spring.dao.IUserDao;
6. import com.spring.model.User;
7. //@Component(value="userService")
8. @Service("userService")     //业务层一般用@Service注入
9. public class UserService implements IUserService {
10. private IUserDao userDao;
11. public IUserDao getUserDao() {
12. return userDao;
13. }
14. //默认通过名称注入，在JSR330中提供了@Inject来注入
15. @Resource
16. public void setUserDao(IUserDao userDao) {
17. this.userDao = userDao;
18. }
19. @Override
20. public void add(User user) {
21. userDao.add(user);
22. }
23. @Override
24. public void delete(int id) {
25. userDao.delete(id);
26. }
27. @Override
28. public User load(int id) {
29. return userDao.load(id);
30. }
31. }

UserAction类：

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1. package com.spring.action;
2. import javax.annotation.Resource;
3. import org.springframework.context.annotation.Scope;
4. import org.springframework.stereotype.Component;
5. import org.springframework.stereotype.Controller;
6. import com.spring.model.User;
7. import com.spring.service.IUserService;
8. //@Component("userAction")
9. @Controller("userAction")   //MVC的控制层一般使用@Controller
10. @Scope("prototype")     //设置多例
11. public class UserAction {
12. private User user;
13. private IUserService userService;
14. private int id;
15. public User getUser() {
16. return user;
17. }
18. public void setUser(User user) {
19. this.user = user;
20. }
21. public IUserService getUserService() {
22. return userService;
23. }
24. @Resource
25. public void setUserService(IUserService userService) {
26. this.userService = userService;
27. }
28. public int getId() {
29. return id;
30. }
31. public void setId(int id) {
32. this.id = id;
33. }
34. public void add(){
35. userService.add(user);
36. }
37. public void delete(){
38. userService.delete(id);
39. }
40. public void load(){
41. userService.load(id);
42. }
43. }

测试类：

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1. package com.spring.test;
2. import org.junit.Test;
3. import org.springframework.beans.factory.BeanFactory;
4. import org.springframework.context.support.ClassPathXmlApplicationContext;
5. import com.spring.action.UserAction;
6. import com.spring.model.User;
7. public class TestSpring {
8. //创建Spring工厂
9. private BeanFactory beanFactory=new ClassPathXmlApplicationContext("beans.xml");
10. @Test
11. public void testUser(){
12. UserAction ua=beanFactory.getBean("userAction",UserAction.class);
13. User user=new User(1,"我叫spring");
14. ua.setUser(user);
15. ua.add();
16. //单例的时候添加相同的内容，多例添加为null
17. UserAction ua1=beanFactory.getBean("userAction",UserAction.class);
18. ua1.add();
19. }
20. }

运行结果及项目结果图：