spring的DI

spring的DI：依赖注入――给属性赋值

说明：
一个类中的属性都可以采用springDI的方式进行赋值，但是并不是所有的属性都适合赋值，固定的配置文件地址，存放到spring中。

springDI的说明：
1、如果spring的配置文件中的bean中没有<constructor-arg>该元素，则调用默认的构造函数
2、如果spring的配置文件中的bean中有<constructor-arg>该元素，则该元素确定唯一的构造函数
index 代表参数的位置 从0开始计算
type 指的是参数的类型
value 给基本类型赋值
ref 给引用类型赋值

Person.java

public class Person {
public Person(){System.out.println("person");}

private Long pid;
private String pname;
private Student student;
private Set sets;
private List lists;
private Map map;
private Properties properties;
set,get方法。。。。。。。。。。。。。
public String toString() {
return "Person [pid=" + pid + ", pname=" + pname + ", student="
+ student + ", sets=" + sets + ", lists=" + lists
+ ", map=" + map + ", properties=" + properties + "]";
}
}

Person_Con.java

public class Person_Con {
private Long pid;
private String pname;
private Student student;
public Person_Con(String pname,Student student){
this.pname = pname;
this.student = student;
}
public Person_Con(Long pid,String pname,Student student){
this.pid = pid;
this.pname = pname;
this.student = student;
}
public Person_Con(){System.out.println("person_Con");}
set,get方法。。。。。。。。。。。。。。
}

applicationContext-di.xml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"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"> 
<bean id="person_con" class="cn.itcast.spring.di.Person_Con">
<constructor-arg index="0" type="java.lang.String" value="pengya"></constructor-arg>
<constructor-arg index="1" type="cn.itcast.spring.di.Student" ref="student"></constructor-arg>
</bean>

<bean id="person" class="cn.itcast.spring.di.Person" >
<property name="pid" value="2"></property>
<property name="pname" value="peng"></property>
<property name="student" ><ref bean="student"/></property>
<property name="lists">
<list>
<value>l1</value>
<value>l2</value>
<ref bean="student"/>
</list>
</property>
<property name="sets">
<set>
<value>s1</value>
<value>s2</value>
<ref bean="student"/>
</set>
</property>
<property name="map">
<map>
<entry key="m1">
<value>map1</value>
</entry>
<entry key="m2">
<ref bean="student"/>
</entry>
</map>
</property>
<property name="properties">
<props>
<prop key="p1">prop1</prop>
<prop key="p2">prop2</prop>
</props>
</property>
</bean>

<bean id="student" class="cn.itcast.spring.di.Student" ></bean>
</beans>