Spring -Spring的 DI - 依赖注入的 使用学习

一 . spring的DI 

 依赖注入，一句话总结 ：给属性赋值 ；
          一个类中的属性都可以采用springDI的方式进行赋值，但是并不是所有的属性都适合赋值；

  1. 利用set给属性赋值

示例：

                （1）当前两个对象 Person和Student

--Person

package cn.labelnet.di.set;public class Person {}

--Student

package cn.labelnet.di.set;import java.util.List;import java.util.Map;import java.util.Set;public class Student {private Integer id;private String sName;private String sPass;private List stus;private Map maps;private Set sets;public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getSName() {return sName;}public void setSName(String name) {sName = name;}public String getSPass() {return sPass;}public void setSPass(String pass) {sPass = pass;}public List getStus() {return stus;}public void setStus(List stus) {this.stus = stus;}public Map<String, String> getMaps() {return maps;}public void setMaps(Map<String, String> maps) {this.maps = maps;}public Set getSets() {return sets;}public void setSets(Set sets) {this.sets = sets;}}

        （2）bean配置和赋值

<?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-2.5.xsd"><bean id="student" class="cn.labelnet.di.set.Student"><property name="id" value="1"></property><property name="maps"><map><entry key="m1"><value>yuan</value></entry><entry key="m2">    <value>zhuo</value></entry><entry key="m3">    <value>ming</value></entry></map></property><property name="sets">        <set>       <value>h1</value>       <value>h2</value>       <ref bean="persion"/>       <value>h4</value>    </set></property><property name="SName"><value>LABELNET</value></property><property name="SPass">     <value>MMMMMMMM</value></property><property name="stus">     <list>       <ref bean="persion"/>       <ref bean="persion"/>     </list></property></bean><bean id="persion" class="cn.labelnet.di.set.Person"></bean></beans>

      （3）总结

              1）引用类型 使用ref 

              2）属性 使用 property

              3）list集合 list

              4）set集合 set

              5）map集合使用 map , entry 

              6）普通类型使用 value

 2. 利用构造函数给属性赋值

1)如果Spring的配置文件中的bean中没有<constructor-arg>元素，则调用默认的构造函数；
2)如果Spring的配置文件中的bean中有<constructor-arg>元素，则该元素确定唯一的构造函数
         index 代表 参数的位置 ，从0开始
type 指的是参数的类型
value 给基本类型赋值
ref 给引用类型赋值

示例：

               （1）实现类 Student

public class Person {private String name;private Integer age;private Student student;public Person(String name,Integer age,Student student) {this.name=name;this.age=age;this.student=student;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public Student getStudent() {return student;}public void setStudent(Student student) {this.student = student;}}

          （2）Student

public class Student {public void hi(){System.out.println("依赖注入 ：DI 构造函数赋值");}}

          （3）bean配置

<?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-2.5.xsd">          <bean id="person_con" class="cn.labelnet.di.constructor.Person">          <constructor-arg index="0" type="java.lang.String" value="yuan"></constructor-arg>          <constructor-arg index="1" type="java.lang.Integer" value="18"></constructor-arg>          <constructor-arg index="2" type="cn.labelnet.di.constructor.Student" ref="student_con"></constructor-arg>     </bean>               <bean id="student_con" class="cn.labelnet.di.constructor.Student"></bean>     </beans>

         （4）测试

public class SpringInit {public final static ApplicationContext context;    static{    context=new ClassPathXmlApplicationContext("ApplicationContext.xml");    }}

public class TestDIConstructor extends SpringInit{@Testpublic void testDICons(){   Person person=(Person) context.getBean("person_con");   System.out.println(person.getName()+" | "+person.getAge());   Student s = person.getStudent();   s.hi();}}

        （5）结果

 
二. SpringIOC和DI的意义 
     实现了完全的面相接口编程
     

    示例：person : child  man oldman

    描述：person接口，有个sayhi方法，使得child，man，oldman均实现person接口和sayhi方法

   （1）Person接口

public interface Person {void sayHi();}

  

    （2）ChildPerson实现

public class ChildPerson implements Person {private String name;private Integer age;     public String getName() {return name;}public void setName(String name) {this.name = name;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public void sayHi(){     System.out.println("小孩子："+this.name+this.age);     }}

   （3）ManPerson实现

package cn.labelnet.implement;public class ManPerson implements Person{private String name;private Integer age;  public void sayHi(){  System.out.println("Man ："+this.name+this.age);     }  public String getName() {return name;}public void setName(String name) {this.name = name;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}}

   （4）OldManPerson实现

package cn.labelnet.implement;public class OldmanPerson implements Person {private String name;private Integer age;public void sayHi() {System.out.println("OldMan：" + this.name + this.age);}public String getName() {return name;}public void setName(String name) {this.name = name;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}}

   （5）PersonManager实现

package cn.labelnet.implement;public class PersonManager {private Person person;public Person getPerson() {return person;}public void setPerson(Person person) {this.person = person;}public void say(){person.sayHi();}}

    （6）bean配置实现

<?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-2.5.xsd"><bean id="child_person_impl" class="cn.labelnet.implement.ChildPerson"><property name="name" value="Child"></property><property name="age" value="18"></property></bean><bean id="man_person_impl" class="cn.labelnet.implement.ManPerson"><property name="name" value="Man"></property><property name="age" value="19"></property></bean><bean id="oldman_person_impl" class="cn.labelnet.implement.OldmanPerson"><property name="name" value="OldMan"></property><property name="age" value="19"></property></bean><bean id="person_manager"  class="cn.labelnet.implement.PersonManager">   <property name="person" ref="child_person_impl"></property> </bean></beans>

   （7）测试

传统的测试方法 ：

Person per=new ChildPerson();PersonManager manager=new PersonManager();manager.setPerson(per);manager.say();

bean.xml测试

public class TestImplement extends SpringInit{@Testpublic void testImlp(){PersonManager manager=(PersonManager) context.getBean("person_manager");manager.say();}}

三.Demo下载

http://download.csdn.net/detail/lablenet/9377346