Spring再接触 注入类型

共有三种注入类型 一种是set注入 一种是构造注入 一种是接口注入 最常用的还是set 现在看一下construct

构造注入

在userservice中加入

package com.bjsxt.service;
import com.bjsxt.dao.UserDAO;
import com.bjsxt.model.User; public class UserService { private UserDAO userDAO;
public void add(User user) {
userDAO.save(user);
}
public UserDAO getUserDAO() {
return userDAO;
}
public void setUserDAO(UserDAO userDAO) {
this.userDAO = userDAO;
} public UserService(UserDAO userDAO) {
super();
this.userDAO = userDAO;
}
}

XML中

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"> <bean id="u" class="com.bjsxt.dao.impl.UserDAOImpl">
</bean> <bean id="userService" class="com.bjsxt.service.UserService">
<!--
<property name="userDAO" ref="u" />
-->
<constructor-arg>
<ref bean="u"/>
</constructor-arg>
</bean> </beans>

测试代码

    @Test
public void testAdd() throws Exception {
ApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml"); UserService service = (UserService)ctx.getBean("userService"); User u = new User();
u.setUsername("zhangsan");
u.setPassword("zhangsan");
service.add(u);
}

这样也是可以成功注入impl的

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