Spring_demo2_Annotation_AutoWired

Annotation-based container configuration

5.9.1. @Required

5.9.2. @Autowired

5.9.3. Fine-tuning annotation-based autowiring with qualifiers

5.9.4. Using generics as autowiring qualifiers

5.9.5. CustomAutowireConfigurer

5.9.6. @Resource

5.9.7. @PostConstruct and @PreDestroy

利用spring一步一步搭建起一个例子(本人采用eclipse)

/**
 * Dao主要做数据库的交互工作
 * Modle 是模型 存放你的实体类
 *Service 做相应的业务逻辑处理
 *Action是一个控制器
 * @author syw
 *
 */

modle:实体类

package com.model;public class User {private String username;private String password;public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}}

 Dao 数据库

package com.dao;import com.model.User;public interface UserDAO {public void saveMySql(User user);public void saveOracle(User user);}

DaoImpl 实现（数据不一样，不一样的实现）

package com.dao.impl;import com.dao.UserDAO;import com.model.User;public class UserDaoImpl implements UserDAO{@Overridepublic void saveMySql(User user) {System.out.println("Mysql: " + user.getUsername());}@Overridepublic void saveOracle(User user) {System.out.println("Oracle: " + user.getPassword());}}

service 业务逻辑处理

package com.service;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.beans.factory.annotation.Qualifier;import com.dao.UserDAO;import com.model.User;public class UserService {private UserDAO userDAO;  public void add(User user) {userDAO.saveMySql(user);}public UserDAO getUserDAO() {return userDAO;}@Autowired//@Qualifier("user2")public void setUserDAO(@Qualifier("user1")UserDAO userDAO) {this.userDAO = userDAO;}}

service 测试类

package com.service;import org.junit.Test;import org.springframework.context.support.ClassPathXmlApplicationContext;import com.model.User;/** * Dao主要做数据库的交互工作 * Modle 是模型 存放你的实体类 *Service 做相应的业务逻辑处理 *Action是一个控制器 * @author tao.zeng * */public class UserServiceTest {@Testpublic void testAdd() throws Exception {ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");UserService service = (UserService)ctx.getBean("userService");User u = new User();u.setUsername("syw");u.setPassword("syw");service.add(u);}}

代码运行：Mysql: syw

源码地址：点击下载

参考：

Because autowiring by type may lead to multiple candidates, 

it is often necessary to have more control over the selection process. One way to accomplish this is with Spring’s @Qualifier annotation. You can associate qualifier values with specific arguments, narrowing the set of type matches so that a specific bean is chosen for each argument. In the simplest case, this can be a plain descriptive value:

public class MovieRecommender {    @Autowired    @Qualifier("main")    private MovieCatalog movieCatalog;    // ...}The @Qualifier annotation can also be specified on individual constructor arguments or method parameters:public class MovieRecommender {    private MovieCatalog movieCatalog;    private CustomerPreferenceDao customerPreferenceDao;    @Autowired    public void prepare(@Qualifier("main")MovieCatalog movieCatalog,            CustomerPreferenceDao customerPreferenceDao) {        this.movieCatalog = movieCatalog;        this.customerPreferenceDao = customerPreferenceDao;    }    // ...}