Java Autowired注解

可以在传统的成员变量，构造器，和setter方法。实现注入

代码实例

Dao

package com.imooc.beanannotation.injection.dao;

public interface InjectionDAO {
	
	public void save(String arg);
	
}

package com.imooc.beanannotation.injection.dao;

import org.springframework.stereotype.Repository;

@Repository
public class InjectionDAOImpl implements InjectionDAO {
	
	public void save(String arg) {
		//模拟数据库保存操作
		System.out.println("保存数据：" + arg);
	}

}

Service类

package com.imooc.beanannotation.injection.service;

public interface InjectionService {
	
	public void save(String arg);
	
}

package com.imooc.beanannotation.injection.service;

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

import com.imooc.beanannotation.injection.dao.InjectionDAO;

@Service
public class InjectionServiceImpl implements InjectionService {
	
//	@Autowired
	private InjectionDAO injectionDAO;
	
	@Autowired
	public InjectionServiceImpl(InjectionDAO injectionDAO) {
		this.injectionDAO = injectionDAO;
	}
	
//	@Autowired
	public void setInjectionDAO(InjectionDAO injectionDAO) {
		this.injectionDAO = injectionDAO;
	}



	public void save(String arg) {
		//模拟业务操作
		System.out.println("Service接收参数：" + arg);
		arg = arg + ":" + this.hashCode();
		injectionDAO.save(arg);
	}
	
}

个人注：Autowired相当于给它注解的类开辟空间

测试类

package com.imooc.test.beanannotation;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.BlockJUnit4ClassRunner;

import com.imooc.beanannotation.injection.service.InjectionService;
import com.imooc.beanannotation.multibean.BeanInvoker;
import com.imooc.test.base.UnitTestBase;

@RunWith(BlockJUnit4ClassRunner.class)
public class TestInjection extends UnitTestBase {
	
	public TestInjection() {
		super("classpath:spring-beanannotation.xml");
	}
	
	@Test
	public void testAutowired() {
		InjectionService service = super.getBean("injectionServiceImpl");
		service.save("This is autowired.");
	}
	
	@Test
	public void testMultiBean() {
		BeanInvoker invoker = super.getBean("beanInvoker");
		invoker.say();
	}
	
}

配置文件

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

Autowired实现多个类的注解

接口类

package com.imooc.beanannotation.multibean;

public interface BeanInterface {

}

实现类1

package com.imooc.beanannotation.multibean;

import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

@Order(2)
@Component
public class BeanImplOne implements BeanInterface {

}

实现类2

package com.imooc.beanannotation.multibean;

import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

@Order(1)
@Component
public class BeanImplTwo implements BeanInterface {

}

注入类

package com.imooc.beanannotation.multibean;

import java.util.List;
import java.util.Map;

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

@Component
public class BeanInvoker {
	
	@Autowired
	private List<BeanInterface> list;
	
	@Autowired
	private Map<String, BeanInterface> map;
	
	@Autowired
	@Qualifier("beanImplTwo") // 表示beanid
	private BeanInterface beanInterface;
	
	public void say() {
		if (null != list && 0 != list.size()) {
			System.out.println("list...");
			for (BeanInterface bean : list) {
				System.out.println(bean.getClass().getName());
			}
		} else {
			System.out.println("List<BeanInterface> list is null !!!!!!!!!!");
		}
		
		System.out.println();
		
		if (null != map && 0 != map.size()) {
			System.out.println("map...");
			for (Map.Entry<String, BeanInterface> entry : map.entrySet()) {
				System.out.println(entry.getKey() + "      " + entry.getValue().getClass().getName());
			}
		} else {
			System.out.println("Map<String, BeanInterface> map is null !!!!!!!!!!");
		}
		
		System.out.println();
		if (null != beanInterface) {
			System.out.println(beanInterface.getClass().getName());
		} else {
			System.out.println("beanInterface is null...");
		}
		
		
	}

}