spring的三种注入方式：
接口注入（不推荐）getter，setter方式注入（比较常用）构造器注入（死的应用）
关于getter和setter方式的注入：
autowire="defualt" autowire=“byName” autowire="bytype" 例如：有如下两个类需要注入
1
package
org.jia;
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3
public
class
Order {
4
private
String orderNum;
5
@SuppressWarnings(
"
unused
"
)
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private
OrderItem orderitem;
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public
OrderItem getOrderitem() {
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return
orderitem;
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}
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public
void
setOrderitem(OrderItem orderitem) {
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this
.orderitem
=
orderitem;
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}
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public
String getOrderNum() {
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return
orderNum;
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}
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public
void
setOrderNum(String orderNum) {
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this
.orderNum
=
orderNum;
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}
23
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}
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package
org.jia;
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public
class
OrderItem {
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private
String orderdec;
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public
String getOrderdec() {
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return
orderdec;
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}
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public
void
setOrderdec(String orderdec) {
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this
.orderdec
=
orderdec;
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}
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}
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getter&&setter方式第一种注入：
<?
xml version="1.0" encoding="UTF-8"
?>
<!
DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"
>
<
beans
>
<
bean
id
="orderItem"
class
="org.jia.OrderItem"
>
<
property
name
="orderdec"
value
="item00001"
></
property
>
</
bean
>
<
bean
id
="order"
class
="org.jia.Order"
> <!-----注入变量 名字必须与类中的名字一样------->
<
property
name
="orderNum"
value
="order000007"
></
property
> <！--注入对象 名字为orderitem，所属的类的应用id为orderItem-->
<
property
name
="orderitem"
ref
="orderItem"
></
property
>
-->
</
bean
>
</
beans
>
getter&&setter方式第二种注入： byName
<?
xml version="1.0" encoding="UTF-8"
?>
<!
DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"
>
<
beans
> <!--此时的id就必须与Order.java中所定义的OrderItem的对象名称一样了，不然就会找不到-->
<
bean
id
="orderitem"
class
="org.jia.OrderItem"
>
<
property
name
="orderdec"
value
="item00001"
></
property
>
</
bean
>
<
bean
id
="order"
class
="org.jia.Order"
autowire
="byName"
>
<
property
name
="orderNum"
value
="order000007"
></
property
>
</
bean
>
</
beans
>
getter&&setter方式第三种注入：byType
<?
xml version="1.0" encoding="UTF-8"
?>
<!
DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"
>
<
beans
> <!--按照byType注入则就与id没有关系，可以随便定义id ！！！但是不能出现多个此类的id-->
<
bean
id
="orderitdfadafaem"
class
="org.jia.OrderItem"
>
<
property
name
="orderdec"
value
="item00001"
></
property
>
</
bean
>
<
bean
id
="order"
class
="org.jia.Order"
autowire
="byType"
>
<
property
name
="orderNum"
value
="order000007"
></
property
>
</
bean
>
</
beans
>
关于构造器的注入： autowire="
constructor"
需要在Order.java中加入一个构造器
public Order(OrderItem item ){ orderitem = item; }
<?
xml version="1.0" encoding="UTF-8"
?>
<!
DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd"
>
<
beans
>
<
bean
id
="orderItem"
class
="org.jia.OrderItem"
>
<
property
name
="orderdec"
value
="item00001"
></
property
>
</
bean
>
<
bean
id
="order"
class
="org.jia.Order"
autowire
="constructor"
>
<
property
name
="orderNum"
value
="order000007"
></
property
>
</
bean
>
</
beans
>
