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  • Spring_Spring与IoC_基于XML的DI

    一、注入分类

    bean实例在调用无参构造器创建空值对象后，就要对Bean对象的属性进行初始化。初始化时由容器自动完成的，称为注入。根据注入方式的不同，常用的有2类：设值注入、构造注入。（还有一种，实现特定接口注入，采用侵入式编程，污染了代码，几乎不用）。

    二、设值注入

     1 public class Student {
 2     private String name;
 3     private int age;
 4     private School school;
 5     public void setName(String name) {
 6         this.name = name;
 7     }
 8     public void setAge(int age) {
 9         this.age = age;
10     }
11     
12     public void setSchool(School school) {
13         this.school = school;
14     }
15     @Override
16     public String toString() {
17         return "Student [name=" + name + ", age=" + age + ", school=" + school + "]";
18     }
19     
20 
21 }
    Student
     1 public class School {
 2     private String name;
 3 
 4     public void setName(String name) {
 5         this.name = name;
 6     }
 7 
 8     @Override
 9     public String toString() {
10         return "School [name=" + name + "]";
11     }
12 
13 }
    School
     1 public class MyTest {
 2 
 3     @Test
 4     public void test01() {
 5         //创建容器对象
 6         String resource = "com/jmu/di01/applicationContext.xml";
 7         ApplicationContext ac=new ClassPathXmlApplicationContext(resource);
 8         Student student = (Student) ac.getBean("myStudent");
 9         System.out.println(student);
10     }
11 
12 }
    MyTest
    1 <bean id="mySchool" class="com.jmu.di01.School">
2         <property name="name" value="清华大学"></property>
3     </bean>
4     <bean id="myStudent" class="com.jmu.di01.Student">
5         <property name="name" value="张三"></property>
6         <property name="age" value="20"></property>
7         <property name="school" ref="mySchool"></property>
8     </bean>
    applicationContext.xml

    三、构造注入

     1 public class Student {
 2     private String name;
 3     private int age;
 4     private School school;
 5     
 6     public Student() {
 7         super();
 8     }
 9     public Student(String name, int age, School school) {
10         super();
11         this.name = name;
12         this.age = age;
13         this.school = school;
14     }
15     
16     @Override
17     public String toString() {
18         return "Student [name=" + name + ", age=" + age + ", school=" + school + "]";
19     }
20     
21 
22 }
    Student
     1 public class School {
 2     private String name;
 3 
 4     public void setName(String name) {
 5         this.name = name;
 6     }
 7 
 8     @Override
 9     public String toString() {
10         return "School [name=" + name + "]";
11     }
12 
13 }
    School
    1 <bean id="mySchool" class="com.jmu.di02.School">
2         <property name="name" value="清华大学"></property>
3     </bean>
4     <bean id="myStudent" class="com.jmu.di02.Student">
5         <constructor-arg name="name"  value="李四"/>
6         <constructor-arg name="age" value="24"/>
7         <constructor-arg name="school"  ref="mySchool"/>
8     </bean>
    applicationContext.xml

    四、P命名空间设值注入

    五、C命名空间构造注入

    六、数组、集合属性注入

     1 import java.util.Arrays;
 2 import java.util.List;
 3 import java.util.Map;
 4 import java.util.Properties;
 5 import java.util.Set;
 6 
 7 public class Some {
 8      private School[] schools;
 9      private String[] myStrs;
10      private List<String> myList;
11      private Set<String> mySet;
12      private Map<String, Object> myMap;
13      private Properties myPros;//key、value均为字符串
14     public void setSchools(School[] schools) {
15         this.schools = schools;
16     }
17     public void setMyStrs(String[] myStrs) {
18         this.myStrs = myStrs;
19     }
20     public void setMyList(List<String> myList) {
21         this.myList = myList;
22     }
23     public void setMySet(Set<String> mySet) {
24         this.mySet = mySet;
25     }
26     public void setMyMap(Map<String, Object> myMap) {
27         this.myMap = myMap;
28     }
29     public void setMyPros(Properties myPros) {
30         this.myPros = myPros;
31     }
32     @Override
33     public String toString() {
34         return "Some [schools=" + Arrays.toString(schools) + ", myStrs=" + Arrays.toString(myStrs) + ", myList="
35                 + myList + ", mySet=" + mySet + ", myMap=" + myMap + ", myPros=" + myPros + "]";
36     }
37      
38 }
    Some
     1 public class School {
 2     private String name;
 3 
 4     public void setName(String name) {
 5         this.name = name;
 6     }
 7 
 8     @Override
 9     public String toString() {
10         return "School [name=" + name + "]";
11     }
12 
13 }
    School
     1 <bean id="mySchool" class="com.jmu.di03.School">
 2         <property name="name" value="清华大学"></property>
 3     </bean>
 4     <bean id="mySchool2" class="com.jmu.di03.School">
 5         <property name="name" value="北京大学"></property>
 6     </bean>
 7     <bean id="mySome" class="com.jmu.di03.Some">
 8         <property name="schools">
 9           <array>
10              <ref bean="mySchool"/>
11              <ref bean="mySchool2"/>
12              
13           </array>
14         </property>
15         
16         <property name="myStrs">
17           <array>
18              <value>中国</value>
19              <value>福建</value>
20           </array>
21         </property>
22         
23         <property name="myList">
24            <list>
25              <value>厦门</value>
26              <value>泉州</value>
27            </list>
28         </property>
29         
30         <property name="mySet">
31           <set>
32             <value>唐朝</value>
33             <value>宋朝</value>
34           </set>
35         </property>
36         
37         <property name="myMap">
38           <map>
39             <entry key="mobile" value="2132124"></entry>
40             <entry key="QQ" value="12424532"></entry>
41           </map>
42         </property>
43         
44         <property name="myPros">
45          <props>
46            <prop key="education">大学</prop>
47            <prop key="gender">男</prop>
48          </props>
49         </property>
50     </bean>
    applicationContext.xml
     1 import org.junit.Test;
 2 import org.springframework.context.ApplicationContext;
 3 import org.springframework.context.support.ClassPathXmlApplicationContext;
 4 
 5 public class MyTest {
 6 
 7     @Test
 8     public void test01() {
 9         //创建容器对象
10         String resource = "com/jmu/di03/applicationContext.xml";
11         ApplicationContext ac=new ClassPathXmlApplicationContext(resource);
12         Some some=(Some) ac.getBean("mySome");
13         System.out.println(some);
14     }
15 
16 }
    MyTest

    输出：

    Some [schools=[School [name=清华大学], School [name=北京大学]], myStrs=[中国, 福建], myList=[厦门, 泉州], mySet=[唐朝, 宋朝], myMap={mobile=2132124, QQ=12424532}, myPros={gender=男, education=大学}]
    output

    简写：

    1 <property name="myStrs" value="中国，福建" />
2         <property name="myList" value="厦门，泉州" />
3         <property name="mySet" value="唐朝，宋朝" />
    applicationContext.xml

    七、对于域属性的自动注入

    1、autowire="byName"会从容器中查找与实体类的域属性同名的Bean的id，并将该Bean对象自动注入给该域属性

    2、autowire="byType"会从容器中查找与实体类的域属性类型具有is-a关系的Bean，并将该Bean对象自动注入给该域属性

     1 <!-- <bean id="mySchool" class="com.jmu.di06.School">
 2         <property name="name" value="集美大学"></property>
 3     </bean> -->
 4     <bean id="myPrimarySchool" class="com.jmu.di06.PrimarySchool">
 5         <property name="address" value="集美区"></property>
 6     </bean>
 7     <bean id="myStudent" class="com.jmu.di06.Student" autowire="byType">
 8         <property name="name" value="张三"></property>
 9         <property name="age" value="20"></property>
10     </bean>
    applicationContext.xml
     1 public class PrimarySchool extends School {
 2     private String address;
 3 
 4     public void setAddress(String address) {
 5         this.address = address;
 6     }
 7 
 8     @Override
 9     public String toString() {
10         return "PrimarySchool [address=" + address + "]";
11     }
12 
13 }
    PrimarySchool

    输出：

    Student [name=张三, age=20, school=PrimarySchool [address=集美区]]
    output

    八、使用SPEL注入

      SPEL,Spring Expression Language,即Spring EL表达式语言。在Spring配置文件中为Bean的属性注入时，可直接使用SPEL表达式计算的结果。

    1 <bean id="myPerson" class="com.jmu.di07.Person">
2        <property name="pname" value="宫本武藏"></property>
3        <property name="page" value="#{T(java.lang.Math).random()*50}"></property>
4     </bean>
5     <bean id="myStudent" class="com.jmu.di07.Student" autowire="byType">
6         <property name="name" value="#{myPerson.pname}"></property>
7         <property name="age" value="#{myPerson.page>25?25:myPerson.page}"></property>
8     </bean>
    applicationContext.xml
    1 Person person=(Person) ac.getBean("myPerson");
2         System.out.println(person);
3         
4         Student student = (Student) ac.getBean("myStudent");
5         System.out.println(student);
    MyTest

    输出：

    1 Person [pname=宫本武藏, page=15]
2 Student [name=宫本武藏, age=15]
    output

    九、内部Bean

    十、同类抽象Bean

    十一、异步抽象Bean

    十二、为应用指定多个Spring配置文件

    1、平等关系

    方式一：

    方式二：

    二、包含关系
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  • 原文地址：https://www.cnblogs.com/hoje/p/8179747.html
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