初学Spring-XML文件配置Bean的一些知识点

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<?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.xsd">    <bean id="..." class="...">        <!-- collaborators and configuration for this bean go here -->    </bean>    <bean id="..." class="...">        <!-- collaborators and configuration for this bean go here -->    </bean>    <!-- more bean definitions go here --></beans>
以上代码摘抄自官方文档。
1.构造注入，setter注入
（1）setter注入，个人代码示例
<bean id="card1" class="beans.Card"><property name="id" value="1"></property><property name="number"><null/></property></bean>
（2）构造注入，个人代码示例
<!--      依赖构造注入可以指定index 和type类型，让属性自动匹配，他们可以混合使用    --><bean id="animal" class="beans.Animal"><constructor-arg value="TOM" index="0"></constructor-arg><constructor-arg value="1000" type="double"></constructor-arg><constructor-arg value="cat" index="2"></constructor-arg></bean>
（3）内部bean
<bean id="worker" class="beans.Worker"><property name="name" value="sam"></property><property name="card" ><!-- 内部bean 只能被自己引用 --> <bean id="card1" class="beans.Card"><property name="id" value="1"></property><property name="number"><null/></property></bean></property></bean>
（4）集合属性配置
<bean id="classroom" class="beansUtil.ClassRoom"><property name="id" value="1"></property><property name="key" value="hello java"></property><property name="students"><list><ref bean="student1"/><ref bean="student2"/></list></property></bean><bean id ="teacher" class="beansUtil.Teacher"><property name="name" value="sam"></property><property name="map"><map><entry key="1" value-ref="student1"></entry></map></property></bean><bean id="pro1" class="beansUtil.pro"><property name="properties"><props><prop key="username">root</prop><prop key="password">123</prop></props></property></bean>
（5）初识scope属性
<bean id="test1" class="beans.autowire.testScope" scope="prototype"><property name="id" value="1"></property></bean>
常用有：prototype singleton（单例，缺省值）
可以使用一个demo来认识scope属性
package beans.autowire;public class testScope {private Integer id;public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}@Overridepublic String toString() {return "testScope [id=" + id + "]";}public testScope(){System.out.println("測試scope");}}
package beans.autowire;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;public class util {public static void main(String[] args) {ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext3.xml");System.out.println(applicationContext);Student student = (Student)applicationContext.getBean("student");System.out.println(student);ClassRoom classRoom = (ClassRoom)applicationContext.getBean("classroom");System.out.println(classRoom);/* * 如果scope设置为singleton的话是单例模式，那么当applicationContext对象被初始化时，则会自动初始化bean * 如果选择prototype则是需要就new */testScope scope1 = (testScope) applicationContext.getBean("test1");testScope scope2= (testScope) applicationContext.getBean("test1");}}
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