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spring之为级联集合属性进行赋值

发布时间:2020-12-15 01:13:37 所属栏目:大数据 来源:网络整理
导读:Car.java package com.gong.spring.beans; public class Car { public Car() { } Car(String name) { this .name = name; } private String name; String getName() { return name; } void setName(String name) { name; } @Override String toString() { re

Car.java

package com.gong.spring.beans;

public class Car {
    
    public Car() {
    }

     Car(String name) {
        this.name = name;
    }
    private String name;

     String getName() {
        return name;
    }

    void setName(String name) {
         name;
    }

    @Override
     String toString() {
        return "Car [name=" + name + "]";
    }
    
}

Student.java

import java.util.List;

 Student {
    
     String name;
    private int age;
    double score;
    private List<Car> cars;
     getAge() {
         age;
    }
    void setAge( age) {
        this.age = getScore() {
         score;
    }
    void setScore( score) {
        this.score = score;
    }
    
    public List<Car> getCars() {
         cars;
    }
    void setCars(List<Car> cars) {
        this.cars = cars;
    }
    @Override
    return "Student [name=" + name + ",age=" + age + ",score=" + score + ",cars=" + cars + "]";
    }
    
    
}

applicationContext.xml

<?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="car1" class="com.gong.spring.beans.Car">
        <property name="name" value="baoma"></property>
    </bean>
    <bean id="car2" class="com.gong.spring.beans.Car">
        <property name="name" value="benchi"></property>
    </bean>
    <bean id="car3" class="com.gong.spring.beans.Car">
        <property name="name" value="binli"></property>
    </bean>
    
    <bean id="student" class="com.gong.spring.beans.Student">
        <property name="name" value="tom"></property>
        <property name="age" value="12"></property>
        <property name="score" value="98.00"></property>
        <property name="cars">
            <!-- 使用List节点为List集合属性赋值 -->
            <list>
                <ref bean="car1"/>
                <ref bean="car2"/>
                <ref bean="car3"/>
            </list>
        </property>
        
    </bean>
    

</beans>

那么,如何对map集合类型进行赋值呢?

修改Student.java

 com.gong.spring.beans;
 java.util.Map;

private Map<String,Car>public Map<String,1)">void setCars(Map<String,1)">;
    }
    
    
}

主要是将car变为Map<String,Car>类型,然后新加getter和setter方法。

在applicationContext.xml中:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"class="com.gong.spring.beans.Student">
        <property name="name" value="tom"></property>
        <property name="age" value="12"></property>
        <property name="score" value="98.00"></property>
        <property name="cars">
            <!-- 使用List节点为List集合属性赋值 
            <list>
                <ref bean="car1"/>
                <ref bean="car2"/>
                <ref bean="car3"/>
            </list>
            -->
            <map>
                <entry key="A" value-ref="car1"></entry>
                <entry key="B" value-ref="car2"></entry>
                <entry key="C" value-ref="car3"></entry>
            </map>
        </property>
        
    </bean>
    

</beans>

最后在Main.java中调用:

 org.springframework.context.ApplicationContext;
 org.springframework.context.support.ClassPathXmlApplicationContext;

 Main {
    static  main(String[] args) {
        //1.创建spring的IOC容器对象
        ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
        2.从容器中获取Bean实例
        Student student = (Student) ctx.getBean("student"); 
        System.out.println(student.toString());
    }
}

输出:

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