spring之setter和构造器注入

一、setter注入

spring配置：

<bean id="firstService" class="com.wgl.spring.core.service.impl.FirstServiceImpl">
　　<property name="firstDao" ref="firstDao"></property>
</bean>
<bean id="firstDao" class="com.wgl.spring.core.dao.impl.FirstDAOImpl"></bean>

FirstServiceImpl.java:

private FirstDAO firstDao;

public void setFirstDao(FirstDAO firstDao) {
this.firstDao = firstDao;
}

二、构造器注入

spring配置：

<bean id="firstService" class="com.wgl.spring.core.service.impl.FirstServiceImpl">
　　<constructor-arg name="firstDao" ref="firstDao"></constructor-arg>
</bean>
<bean id="firstDao" class="com.wgl.spring.core.dao.impl.FirstDAOImpl"></bean>

FirstServiceImpl.java:

private FirstDAO firstDao;
public FirstServiceImpl(FirstDAO firstDao){
this.firstDao = firstDao;
}