spring 注解配置bean2

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1.UserService类

package com.hxzy.annotation.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;

import com.hxzy.annotation.repository.UserRepository;

//模拟业务层,服务层
@Service
public class UserService {

//autowired可以放在构造器上、属性上、有参数的方法上,以下是将autowired放在属性上
@Autowired
// @Qualifier("userRepositoryImpl") //此处使用Qualifier时，需要修改Test类中的ctx.getBean()中的参数
private UserRepository userRepository;

//autowired放在set方法上(set方法有参数)
// @Autowired
public void setUserRepository(UserRepository userRepository) {
this.userRepository = userRepository;
}

public void add() {
System.out.println("UserService add...");
userRepository.save();
}
}

2.UserRepositoryImpl类

package com.hxzy.annotation.repository;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Repository;

import com.hxzy.annotation.TestObject;

//模拟持久化层 //此处的参数("userRepository")如果不写，则接口实现类为两个时(UserRepositoryImpl、 UserJdbcRepository)
//会提示如下错误：.UserRepository] is defined: expected single matching bean but found 2: userJdbcRepository,userRepositoryImpl
@Repository("userRepository")
public class UserRepositoryImpl implements UserRepository {

//如果TestObject类中缺少@Component声明，则此处即便使用AutoWired，也会出现BeanCreationException异常
//如果在TestObject类中无@Component声明，此处可以在Autowired中添加参数required=false，使得testObject不被调用，这样就不会报出异常了。
@Autowired(required=false)
private TestObject testObject;

@Override
public void save() {

System.out.println("UserRepository save...");
System.out.println(testObject);

}

}

3.UserJdbcRepository 类

package com.hxzy.annotation.repository;

public class UserJdbcRepository implements UserRepository {

@Override
public void save() {
System.out.println("UserJdbcRepository save");
}

}

4.UserRepository 接口

package com.hxzy.annotation.repository;

public interface UserRepository {

void save();

}

5.UserController 类

package com.hxzy.annotation.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;

import com.hxzy.annotation.service.UserService;

//模拟表现层
@Controller
public class UserController {

//使用注解建立bean与bean之间的引用关系
@Autowired
private UserService userService;

public void execute() {
System.out.println("UserController execute...");
userService.add();
}
}

6.bean配置文件（基本没用上）

<?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-4.0.xsd">







<context:component-scan
base-package="com.hxzy.annotation"
use-default-filters="true"
>


<context:include-filter type="assignable" expression="com.hxzy.annotation.repository.UserRepository"/>


</context:component-scan>

</beans>

7.测试类

package com.hxzy.annotation;

import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.stereotype.Repository;

import com.hxzy.annotation.controller.UserController;
import com.hxzy.annotation.repository.UserRepository;
import com.hxzy.annotation.service.UserService;

public class Test {

public static void main(String[] args) {
ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("annotation.xml");
//使用spring 的默认命名策略，testObject对象是基于TestObject类，将TestObject类的首字母小写，作为bean对象，不在配置文件中专门配置bean
// TestObject to = (TestObject) ctx.getBean("testObject");
// System.out.println(to);
//
// //UserController类的首字母小写，作为bean对象
UserController userControl = (UserController) ctx.getBean("userController");
userControl.execute();
System.out.println(userControl);
//
// UserService userService = (UserService) ctx.getBean("userService");
// System.out.println(userService);

//在UserRepository类中注解若使用@Repository("userRepository")，则此处的ctx.getBean()中参数与注解中的参数相同
//否则若UserRepository类中注解若使用@Repository，此处ctx.getBean("userRepositoryImpl")
UserRepository userRepository = (UserRepository) ctx.getBean("userRepository");
System.out.println(userRepository);

ctx.close();
}
}

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