Spring_spring自动装配置注解(@Autowired)指定要装配置的参数(@Qualifier)

ゝ一世哀愁。 2022-06-15 03:46 182阅读 0赞

@Autowired
    	a>默认按类型by type
    	b>如果想用byName,使用Qulifler
    	c>写在private field(第三种注入形式)(不建议,破封装)
    	d>如果写在set上,@qualifier需要写在参数上

导入spring注解配置

xmlns:context="http://www.springframework.org/schema/context

http://www.springframework.org/schema/context

http://www.springframework.org/schema/context/spring-context.xsd">

<?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">
    
    	<context:annotation-config />
    	<bean id="userDaoImpl" class="com.bjsxd.dao.impl.UserDaoImpl">
    	</bean>
    	<bean id="userDaoImpl2" class="com.bjsxd.dao.impl.UserDaoImpl">
    	</bean>
    
    	<bean id="userService" class="com.bjsxd.service.UserService">
    	
    	</bean>
    </beans>

package com.bjsxd.service;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.beans.factory.annotation.Qualifier;
    
    import com.bjsxd.dao.UserDao;
    import com.bjsxd.model.User;
    
    public class UserService {
    	private UserDao userDao;
    
    	public UserDao getUserDao() {
    		return userDao;
    	}
    
    	@Autowired//自动装配
    	public void setUserDao(@Qualifier("userDaoImpl")UserDao userDao) {//指定要使用的的bean的ID注入
    		this.userDao = userDao;
    	}
    
    	public void add(User user) {
    		userDao.save(user);
    	}
    }