官方文檔基于XMl的DI
1.設值注入
2.構造注入
3.p命名空間設值注入
4.c命名空間構造注入
設值注入
調用屬性的set方法,使用 <property name="name" value="FutaoSmile"/>
環境搭建 -- 屬性需要set方法,類不需要構造方法
Bean-Student
/**
* Created by futao on 2017/10/10.
*/
public class Student {
private String name;
private int age;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public String toString() {
return "Student{" +
"name='" + name + '\'' +
", age=" + age +
'}';
}
}
配置檔案-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.xsd">
<bean id="student" class="Student">
</bean>
</beans>
測試
import org.junit.Test
import org.springframework.context.support.ClassPathXmlApplicationContext
/**
* Created by futao on 2017/10/10.
*/
class Mytest {
@Test
fun forTest() {
val xml = ClassPathXmlApplicationContext("applicationContext.xml")
val student = xml.getBean("student") as Student
println(student)
}
}
輸出結果
Student{name='null', age=0}
修改配置檔案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.xsd">
<bean id="student" class="Student">
<!--設值注入,實際上是通過調用set方法實作-->
<property name="name" value="FutaoSmile"/>
<property name="age" value="18"/>
</bean>
</beans>
測試結果:
Student{name='FutaoSmile', age=18}
建立School類
/**
* Created by futao on 2017/10/10.
*/
public class School {
private String schoolName;
public String getSchoolName() {
return schoolName;
}
public void setSchoolName(String schoolName) {
this.schoolName = schoolName;
}
@Override
public String toString() {
return "School{" +
"schoolName='" + schoolName + '\'' +
'}';
}
}
School在Student類中作為屬性存在
/**
* Created by futao on 2017/10/10.
*/
public class Student {
private String name;
private int age;
private School school;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public School getSchool() {
return school;
}
public void setSchool(School school) {
this.school = school;
}
@Override
public String toString() {
return "Student{" +
"name='" + name + '\'' +
", age=" + age +
", school=" + school +
'}';
}
}
修改配置檔案applicationContext.xml注入school屬性值
<?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.xsd">
<bean id="student" class="Student">
<!--設值注入,實際上是通過調用set方法實作-->
<!-- 即:property标簽調用到的是set方法 -->
<property name="name" value="FutaoSmile"/>
<property name="age" value="18"/>
<!-- 添加school的引用 -->
<property name="school" ref="school"/>
</bean>
<bean id="school" class="School">
<property name="schoolName" value="Ecjtu"/>
</bean>
</beans>
測試結果
Student{name='FutaoSmile', age=18, school=School{schoolName='Ecjtu'}}
基于XMl的DI-構造注入
直接調用帶參構造器 - 使用
<constructor-arg name="0" value="李四"/>
構造注入
環境搭建 -- 屬性不需要set方法,類需要帶參的構造方法
Student類
package gouzaoDI;
/**
* Created by futao on 2017/10/10.
*/
public class Student {
private String name;
private int age;
private School school;
/**
* 帶參構造器
*
* @param name 姓名
* @param age 年齡
* @param school 學校
*/
public Student(String name, int age, School school) {
this.name = name;
this.age = age;
this.school = school;
}
/**
* 無參構造器
*/
public Student() {
}
@Override
public String toString() {
return "Student{" +
"name='" + name + '\'' +
", age=" + age +
", school=" + school +
'}';
}
}
School類
package gouzaoDI;
/**
* Created by futao on 2017/10/10.
*/
public class School {
private String schoolName;
/**
* 帶參構造方法
*
* @param schoolName 學校名稱
*/
public School(String schoolName) {
this.schoolName = schoolName;
}
/**
* 無參構造方法
*/
public School() {
}
@Override
public String toString() {
return "School{" +
"schoolName='" + schoolName + '\'' +
'}';
}
}
配置檔案applicationContextGouzaoDI.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.xsd">
<bean id="student" class="gouzaoDI.Student">
<!--構造注入方式1,用index,實際上是通過構造方法注入,index表示構造方法的參數索引-->
<!--<constructor-arg index="0" value="李四"/>-->
<!--<constructor-arg index="1" value="18"/>-->
<!--<constructor-arg index="2" ref="school"/>-->
<!--構造注入方式2,用name-->
<!--<constructor-arg name="name" value="李四"/>-->
<!--<constructor-arg name="age" value="18"/>-->
<!--<constructor-arg name="school" ref="school"/>-->
<!--構造注入方式3,省略index和name,但是這樣要保證順序與構造方法中參數的順序是一樣的-->
<constructor-arg value="李四"/>
<constructor-arg value="18"/>
<constructor-arg ref="school"/>
</bean>
<bean id="school" class="gouzaoDI.School">
<constructor-arg index="0" value="華東交通大學"/>
</bean>
</beans>
/**
* 構造注入- 通過類的帶參構造方法
*/
@Test
fun test4gouzaoDI() {
val xml = ClassPathXmlApplicationContext("applicationContextGouzaoDI.xml")
val student = xml.getBean("student") as gouzaoDI.Student
println(student)
}
結果
Student{name='李四', age=18, school=School{schoolName='華東交通大學'}}
P名字空間設值注入 p:schoolName="East China JiaoTong University"
實際上是通過屬性的set方法實作的,是以如果要通過p名字空間進行設隻注入的屬性,需要為該屬性設定setter
XML shortcut with the p-namespace
The p-namespace enables you to use the bean element’s attributes, instead of nested
elements(property), to describe your property values and/or collaborating beans.
<property/>
配置檔案applicationContextPnamespaceDI.xml
注意:需要添加限制
xmlns:p="http://www.springframework.org/schema/p"
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:p="http://www.springframework.org/schema/p"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<!--p名字空間設值注入的原理其實是通過屬性的set方法實作的,通過追蹤代碼可以出來-->
<bean id="student" class="PnamespaceDI.Student" p:name="麻子" p:age="18" p:school-ref="school"/>
<bean id="school" class="PnamespaceDI.School" p:schoolName="East China JiaoTong University"/>
</beans>
/**
* p命名空間設值注入
*/
@Test
fun test4pNamespaceDI() {
val xml = ClassPathXmlApplicationContext("applicationContextPnamespaceDI.xml")
val student = xml.getBean("student") as PnamespaceDI.Student
println(student)
}
Student{name='麻子', age=18, school=School{schoolName='East China Jiao Tong University'}}
c名字空間構造注入 - c:schoolName="華東交通大學"
添加限制
xmlns:c="http://www.springframework.org/schema/c"
原理:c名字空間構造注入,原理實際上是通過類的構造方法實作的,是以要使用c名字空間注入就需要為類添加帶參的構造方法
XML shortcut with the c-namespace
Similar to the the section called “XML shortcut with the p-namespace”, the c-namespace, newly introduced in Spring 3.1, allows usage of inlined attributes for configuring the constructor arguments rather then nested constructor-arg elements.
applicationContextCnamespaceDI.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" xmlns:c="http://www.springframework.org/schema/c"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
<!--p名字空間設值注入的原理其實是通過屬性的set方法實作的,通過追蹤代碼可以出來-->
<!--<bean id="student" class="PnamespaceDI.Student" p:name="麻子" p:age="18" p:school-ref="school"/>-->
<!--<bean id="school" class="PnamespaceDI.School" p:schoolName="East China JiaoTong University"/>-->
<!--c名字空間構造注入,原理實際上是通過類的構造方法實作的-->
<bean id="student" class="PnamespaceDI.Student" c:name="coder" c:age="18" c:school-ref="school"/>
<bean id="school" class="PnamespaceDI.School" c:schoolName="華東交通大學"/>
</beans>
Student{name='coder', age=18, school=School{schoolName='華東交通大學'}}