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

 public class Student {
     private String name;
     private int age;
     private School school;
     public void setName(String name) {
         this.name = name;
     }
     public void setAge(int age) {
         this.age = age;
     }

     public void setSchool(School school) {
         this.school = school;
     }
     @Override
     public String toString() {
         return "Student [name=" + name + ", age=" + age + ", school=" + school + "]";
     }

 }

Student

 public class School {
     private String name;

     public void setName(String name) {
         this.name = name;
     }

     @Override
     public String toString() {
         return "School [name=" + name + "]";
     }

 }

School

 public class MyTest {

     @Test
     public void test01() {
         //创建容器对象
         String resource = "com/jmu/di01/applicationContext.xml";
         ApplicationContext ac=new ClassPathXmlApplicationContext(resource);
         Student student = (Student) ac.getBean("myStudent");
         System.out.println(student);
     }

 }

MyTest

 <bean id="mySchool" class="com.jmu.di01.School">
         <property name="name" value="清华大学"></property>
     </bean>
     <bean id="myStudent" class="com.jmu.di01.Student">
         <property name="name" value="张三"></property>
         <property name="age" value="20"></property>
         <property name="school" ref="mySchool"></property>
     </bean>

applicationContext.xml

三、构造注入

 public class Student {
     private String name;
     private int age;
     private School school;

     public Student() {
         super();
     }
     public Student(String name, int age, School school) {
         super();
         this.name = name;
         this.age = age;
         this.school = school;
     }

     @Override
     public String toString() {
         return "Student [name=" + name + ", age=" + age + ", school=" + school + "]";
     }

 }

Student

 public class School {
     private String name;

     public void setName(String name) {
         this.name = name;
     }

     @Override
     public String toString() {
         return "School [name=" + name + "]";
     }

 }

School

 <bean id="mySchool" class="com.jmu.di02.School">
         <property name="name" value="清华大学"></property>
     </bean>
     <bean id="myStudent" class="com.jmu.di02.Student">
         <constructor-arg name="name"  value="李四"/>
         <constructor-arg name="age" value="24"/>
         <constructor-arg name="school"  ref="mySchool"/>
     </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

 import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
 import java.util.Set;

 public class Some {
      private School[] schools;
      private String[] myStrs;
      private List<String> myList;
      private Set<String> mySet;
      private Map<String, Object> myMap;
      private Properties myPros;//key、value均为字符串
     public void setSchools(School[] schools) {
         this.schools = schools;
     }
     public void setMyStrs(String[] myStrs) {
         this.myStrs = myStrs;
     }
     public void setMyList(List<String> myList) {
         this.myList = myList;
     }
     public void setMySet(Set<String> mySet) {
         this.mySet = mySet;
     }
     public void setMyMap(Map<String, Object> myMap) {
         this.myMap = myMap;
     }
     public void setMyPros(Properties myPros) {
         this.myPros = myPros;
     }
     @Override
     public String toString() {
         return "Some [schools=" + Arrays.toString(schools) + ", myStrs=" + Arrays.toString(myStrs) + ", myList="
                 + myList + ", mySet=" + mySet + ", myMap=" + myMap + ", myPros=" + myPros + "]";
     }

 }

Some

 public class School {
     private String name;

     public void setName(String name) {
         this.name = name;
     }

     @Override
     public String toString() {
         return "School [name=" + name + "]";
     }

 }

School

 <bean id="mySchool" class="com.jmu.di03.School">
         <property name="name" value="清华大学"></property>
     </bean>
     <bean id="mySchool2" class="com.jmu.di03.School">
         <property name="name" value="北京大学"></property>
     </bean>
     <bean id="mySome" class="com.jmu.di03.Some">
         <property name="schools">
           <array>
              <ref bean="mySchool"/>
              <ref bean="mySchool2"/>

           </array>
         </property>

         <property name="myStrs">
           <array>
              <value>中国</value>
              <value>福建</value>
           </array>
         </property>

         <property name="myList">
            <list>
              <value>厦门</value>
              <value>泉州</value>
            </list>
         </property>

         <property name="mySet">
           <set>
             <value>唐朝</value>
             <value>宋朝</value>
           </set>
         </property>

         <property name="myMap">
           <map>
             <entry key="mobile" value="2132124"></entry>
             <entry key="QQ" value="12424532"></entry>
           </map>
         </property>

         <property name="myPros">
          <props>
            <prop key="education">大学</prop>
            <prop key="gender">男</prop>
          </props>
         </property>
     </bean>

applicationContext.xml

 import org.junit.Test;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.support.ClassPathXmlApplicationContext;

 public class MyTest {

     @Test
     public void test01() {
         //创建容器对象
         String resource = "com/jmu/di03/applicationContext.xml";
         ApplicationContext ac=new ClassPathXmlApplicationContext(resource);
         Some some=(Some) ac.getBean("mySome");
         System.out.println(some);
     }

 }

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：

 <property name="myStrs" value="中国，福建" />
         <property name="myList" value="厦门，泉州" />
         <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

 <!-- <bean id="mySchool" class="com.jmu.di06.School">
         <property name="name" value="集美大学"></property>
     </bean> -->
     <bean id="myPrimarySchool" class="com.jmu.di06.PrimarySchool">
         <property name="address" value="集美区"></property>
     </bean>
     <bean id="myStudent" class="com.jmu.di06.Student" autowire="byType">
         <property name="name" value="张三"></property>
         <property name="age" value="20"></property>
     </bean>

applicationContext.xml

 public class PrimarySchool extends School {
     private String address;

     public void setAddress(String address) {
         this.address = address;
     }

     @Override
     public String toString() {
         return "PrimarySchool [address=" + address + "]";
     }

 }

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。

 <bean id="myPerson" class="com.jmu.di07.Person">
        <property name="pname" value="宫本武藏"></property>
        <property name="page" value="#{T(java.lang.Math).random()*50}"></property>
     </bean>
     <bean id="myStudent" class="com.jmu.di07.Student" autowire="byType">
         <property name="name" value="#{myPerson.pname}"></property>
         <property name="age" value="#{myPerson.page>25?25:myPerson.page}"></property>
     </bean>

applicationContext.xml

 Person person=(Person) ac.getBean("myPerson");
         System.out.println(person);

         Student student = (Student) ac.getBean("myStudent");
         System.out.println(student);

MyTest

输出：

 Person [pname=宫本武藏, page=15]
 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