spring_spring注解资源@Resource、组件注解@Component

深碍√TFBOYSˉ_ 2022-06-15 03:54 215阅读 0赞

@Resource(重要)
    	a>默认按名称,名称找不到,按类型
    	b>可以指定特定名称
    	c>推荐使用
    	d>不足:如果没有源码,就无法运用annotation,只能使用xml
    @Componert
    	a>初如化的名字默认为类名首字母小写
    	b>可以指定初始化bean的名字

@Resource

<?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>

对set方法进行注入

package com.bjsxd.service;
    
    import javax.annotation.Resource;
    
    import com.bjsxd.dao.UserDao;
    import com.bjsxd.model.User;
    
    public class UserService {
    	private UserDao userDao;
    
    	public UserDao getUserDao() {
    		return userDao;
    	}
    
    	@Resource(name="userDaoImpl2")
    	public void setUserDao(UserDao userDao) {
    		this.userDao = userDao;
    	}
    
    	public void add(User user) {
    		userDao.save(user);
    	}
    }

@Component

自动扫描注入

<?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 />
    	<context:component-scan base-package="com.bjsxt" />
    </beans>

package com.bjsxt.dao.impl;
    
    import org.springframework.stereotype.Component;
    
    import com.bjsxt.dao.UserDao;
    import com.bjsxt.model.User;
    @Component("userDaoImpl")
    public class UserDaoImpl implements UserDao{
    
    	@Override
    	public void save(User user) {
    		System.out.println("user save!");
    	}
    
    }

package com.bjsxt.service;
    
    import javax.annotation.Resource;
    
    import org.springframework.stereotype.Component;
    
    import com.bjsxt.dao.UserDao;
    import com.bjsxt.model.User;
    @Component("userService")
    public class UserService {
    	private UserDao userDao;
    
    	public UserDao getUserDao() {
    		return userDao;
    	}
    
    	@Resource(name="userDaoImpl")
    	public void setUserDao(UserDao userDao) {
    		this.userDao = userDao;
    	}
    
    	public void add(User user) {
    		userDao.save(user);
    	}
    }