spring注入方式之construct方式注入

被注入的类必须存在一个无参构造函数（按参数顺序和按参数类型两种方式）

Dao

public class PersonDao {
	private Integer age;
	private String name;
	
	public PersonDao() {

	}
	/**
	 * 如果是按照参数顺序来注入,那么可以在<constructor-arg index="1">中设置index来区分以下两个构造函数
	 * 
	 * 如果是按参数类型来注入,那么以下两个构造函数谁在前面就执行哪个
	 * 
	 * 注意：如果参数是int类型,<constructor-arg  type="java.lang.Integer">会出异常
	 */
	public PersonDao(String name,Integer age) {
		System.out.println("name,age");
		this.age = age;
		this.name = name;
	}

	public PersonDao(Integer age, String name) {
		System.out.println("age,name");
		this.age = age;
		this.name = name;
	}

	public String toString() {
		return "PersonDao [age=" + age + ", name=" + name + "]";
	}
	
}

applicationContext.xml

<?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">
	<!-- 构造方法注入之参数顺序注入 
	<bean id="personDao" class="com.xxc.iocc.construct.dao.PersonDao">
		<constructor-arg index="1">
			<value>zhang</value>
		</constructor-arg>
		<constructor-arg index="0">
			<value>2</value>
		</constructor-arg>
	</bean>-->
	
	 <!-- 构造方法注入之参数类型注入 -->
	 <bean id="personDao" class="com.xxc.iocc.construct.dao.PersonDao">
		 <constructor-arg  type="java.lang.String">
            <value>zhang</value>
         </constructor-arg>
         
       <constructor-arg  type="java.lang.Integer">
            <value>123</value>
         </constructor-arg>
	</bean>
</beans>

测试类

public class Test {
	public static void main(String[] args) {
		ApplicationContext ac = new ClassPathXmlApplicationContext("com/xxc/iocc/construct/applicationContext.xml");
		PersonDao personDao = (PersonDao)ac.getBean("personDao");
		System.out.println(personDao.toString());
	}
}