spring依赖注入方法

本例都是在局部配置文件中配置的，也可以在applicationContext.xml文件中直接进行配置，为了说明方便，这里用的局部配置方法。

（1）通过构造方法

创建一个类Cat

package cn.java.di;

 

public class Cat {

     private String name;

     private Integer age;

     private Float weight;

     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 Float getWeight() {

         return weight;

     }

     public void setWeight(Float weight) {

         this .weight = weight;

     }

     public Cat() {

         System.out.println( "无参构造方法" );

     }

     public Cat(String name, Integer age, Float weight) {

         super ();

         this .name = name;

         this .age = age;

         this .weight = weight;

         System.out.println( "有参构造方法" );

     }

     @Override

     public String toString() {

         return "Cat [name=" + name + ", age=" + age + ", weight=" + weight + "]" ;

     }

     

}

创建一个局部配置文件：

<!--?xml version= "1.0" encoding= "UTF-8" ?-->

<beans xmlns= "https://www.springframework.org/schema/beans"

    xmlns:xsi= "https://www.w3.org/2001/XMLSchema-instance"

    xsi:schemalocation="https://www.springframework.org/schema/beans

    https: //www.springframework.org/schema/beans/spring-beans-2.5.xsd">

    <bean class = "cn.java.di.Cat" id= "cat" >

        <constructor-arg index= "0" type= "java.lang.String" value= "tom" ></constructor-arg>

        <constructor-arg index= "1" type= "java.lang.Integer" value= "10" ></constructor-arg>

        <constructor-arg index= "2" type= "java.lang.Float" value= "2.5" ></constructor-arg>

    </bean>

</beans>

然后在applicationContext.xml文件中将其关联：

<!--?xml version= "1.0" encoding= "UTF-8" ?-->

<beans xmlns= "https://www.springframework.org/schema/beans"

    xmlns:xsi= "https://www.w3.org/2001/XMLSchema-instance"

    xsi:schemalocation="https://www.springframework.org/schema/beans

     https: //www.springframework.org/schema/beans/spring-beans-2.5.xsd">

           

      <!-- bean:将一个类的对象创建过程交给spring容器 class ：指定类的具体路径 id：唯一标识符

       scope:用来控制spring容器产生对象的方式，可以为单例也可以为多例。

            常用的值为singleton(单例),prototype(多例)，默认的是单例。    

       init-method:表示初始化方法，只写初始化方法的名字，不用加上();

      -->


       < import resource= "cn/java/di/Cat.xml" ></ import >

</beans>

创建一个测试类：

package cn.java.ioc1;

 

import org.springframework.context.ApplicationContext;

import org.springframework.context.support.ClassPathXmlApplicationContext;

 

import cn.java.di.Cat;

import cn.java.initAndDistroy.Ji;

import cn.java.lazy.Duck;

import cn.java.singleton2.Dog;

 

public class Window {

 

     public static void main(String[] args) {

         //启动框架(context代表spring容器)

         ApplicationContext context= new ClassPathXmlApplicationContext( "applicationContext.xml" ); //只写这句也可以调用YellowMouseWolf类中的无参构造方法

          System.out.println( "-----------------------" );

         //获取spring容器中创建的对象(通过id值获取)

         Cat cat=(Cat)context.getBean( "cat" );

         

     }

 

}

（2）通过get/set方法赋值

这时只需要修改：

<!--?xml version= "1.0" encoding= "UTF-8" ?-->

<beans xmlns= "https://www.springframework.org/schema/beans"

    xmlns:xsi= "https://www.w3.org/2001/XMLSchema-instance"

    xsi:schemalocation="https://www.springframework.org/schema/beans

        https: //www.springframework.org/schema/beans/spring-beans-2.5.xsd">              

         

             <bean class = "cn.java.di.Cat" id= "cat" >

                  <property name= "name" value= "jack" ></property>

                  <property name= "age" value= "20" ></property>

                  <property name= "weight" value= "5.2" ></property>                

             </bean>    

                      

  </beans>