跟随小破站学习java spring框架第四天

技术2022-07-11 91

首先在项目中namespace导入p命名空间可以方便定义对象属性

<bean id="s1" class="com.atguigu.spring.di.Student"> <property name="id"> <value>10010</value> //通过value标签进行赋值 </property> <property name="name" value="张三"></property> <property name="age" value="23"></property> <property name="sex" value="男"></property> </bean>

ref关键字!

<bean id="s5" class="com.atguigu.spring.di.Student"> <property name="id" value="10055"></property> <property name="name" value="张三三"></property> <property name="age" value="23"></property> <property name="sex" value="男"></property> <property name="teacher" ref="teacher"></property>//通过ref使用其他类的值 <property name="teacher.tname" value="徐老师"></property>//通过修改标识来进行值的修改 </bean> <bean id="teacher" class="com.atguigu.spring.di.Teacher"> <property name="tid" value="10000"></property> <property name="tname" value="于老师"></property> </bean>

private List<String> cls; <bean id="t1" class="com.atguigu.spring.di.Teacher"> <property name="tid" value="10001"></property> <property name="tname" value="何老师"></property> <property name="cls"> <list> <value>A</value> <value>B</value> <value>C</value> </list> </property> </bean> private List<Student> students; //注意命名格式格式错误时无法赋值 <bean id="t2" class="com.atguigu.spring.di.Teacher"> <property name="tid" value="10002"></property> <property name="tname" value="李老师"></property> <property name="students"> <list> <ref bean="s1"/> <ref bean="s2"/> <ref bean="s3"/> </list> </property> </bean> private Map<String,String> bossMap; //map数组中一个entry代表一个"键值"对 <bean id="t3" class="com.atguigu.spring.di.Teacher"> <property name="tid" value="10003"></property> <property name="tname" value="admin"></property> <property name="bossMap"> <map> <entry> <key> <value>10001</value> </key> <value>佟老师</value> </entry> <entry> <key> <value>10002</value> </key> <value>陈老师</value> </entry> </map> </property> </bean>

private List<Student> students; <bean id="t4" class="com.atguigu.spring.di.Teacher"> <property name="tid" value="10004"></property> <property name="tname" value="root"></property> <property name="students" ref="s"></property> </bean> <util:list id="s"> //此时的students指的是Student类的集合 <ref bean="s4"/> <ref bean="s5"/> <ref bean="s6"/> </util:list> //对于map集合也适用 <util:map id="map"> <entry> <key> <value>1</value> </key> <value>张三</value> </entry> </util:map>

注意:

出错原因:

<util:list id="s"> <list> <ref bean="s4"/> <ref bean="s5"/> <ref bean="s6"/> </list> </util:list> //list中包含的是student对象的类而不应该是一个集合

工厂bean FactoryBean

public class Car { private String brand; private Double price; public String getBrand() { return brand; } public void setBrand(String brand) { this.brand = brand; } public Double getPrice() { return price; } public void setPrice(Double price) { this.price = price; } @Override public String toString() { return "Car [brand=" + brand + ", price=" + price + "]"; } } //实现工厂设计模式FactoryBean public class MyFacory implements FactoryBean<Car> { //获取对象 @Override public Car getObject() throws Exception { Car car = new Car();//工厂式创建对象 car.setBrand("奥迪"); car.setPrice(200000.0); return car; } //获取对象类型所属类型 @Override public Class<?> getObjectType() { return Car.class; } //是否为单例模式 @Override public boolean isSingleton() { return false; } } <bean id="factory" class="com.atguigu.spring.factorybean.MyFacory"> </bean> public class Test { public static void main(String[] args) { ApplicationContext ac = new ClassPathXmlApplicationContext("factory-bean.xml"); Object object = ac.getBean("factory"); System.out.println(object);//获取的是MyFactory下创建的car对象 } }

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