通过实例解析spring bean之间的关系

这篇文章主要介绍了通过实例解析spring bean之间的关系,文中通过示例代码介绍的非常详细，对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下

两种关系：继承、依赖

一、继承关系

Address.java

package com.gong.spring.beans.autowire; public class Address { private String city; private String street; public String getCity() { return city; } public void setCity(String city) { this.city = city; } public String getStreet() { return street; } public void setStreet(String street) { this.street = street; } @Override public String toString() { return "Address [city=" + city + ", street=" + street + "]"; } }

beans-relation.xml

Main.java

package com.gong.spring.beans.autowire; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClasspathXmlApplicationContext; public class Main { public static void main(String[] args) { //1.创建spring的IOC容器对象 ApplicationContext ctx = new ClasspathXmlApplicationContext("beans-relation.xml"); //2.从容器中获取Bean实例 Address address = (Address) ctx.getBean("address"); System.out.println(address.toString()); Address address2 = (Address) ctx.getBean("address2"); System.out.println(address2.toString()); } }

输出：

address2继承了address的city配置，因此city=武汉。

当然，我们也可以使用abstract来表明一个Bean是一个抽象Bean。抽象Bean可以作为一个模板，且不能被实例化。同时，如果一个bean没有声明class，那么该bean也是一个抽象Bean，且必须指定abstract="true"。

此时，在进行实例化就会报错

Address address = (Address) ctx.getBean("address");

将抽象Bean作为父bean，可以实例化它的子Bean：

Address address2 = (Address) ctx.getBean("address2"); System.out.println(address2.toString());

二、依赖关系

Car.java

package com.gong.spring.beans.autowire; public class Car { public Car() { } public Car(String name) { this.name = name; } private String name; public String getName() { return name; } public void setName(String name) { this.name = name; } @Override public String toString() { return "Car [name=" + name + "]"; } }

Student.java

package com.gong.spring.beans.autowire; import java.util.List; import java.util.Map; public class Student { private String name; private int age; private double score; private Car car; private Address address; public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public double getscore() { return score; } public void setscore(double score) { this.score = score; } public Car getCar() { return car; } public void setCar(Car car) { this.car = car; } public Address getAddress() { return address; } public void setAddress(Address address) { this.address = address; } @Override public String toString() { return "Student [name=" + name + ", age=" + age + ", score=" + score + ", car=" + car + ", address=" + address + "]"; } }

beans-relation.xml

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