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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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