spring使用JavaConfig进行配置的方法

2024-04-02 19:55

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JavaConfig，是在 Spring 3.0 开始从一个独立的项目并入到 Spring 中的。JavaConfig 可以看成一个用于完成 Bean 装配的 Spring 配置文件，即 Spring 容器，只不过该容器不是 XML文件，而是由程序员使用 Java 自己编写的 Java 类。

实体类：


package com.lzl.spring.entity;
 
public class Car {
	private String brand;//品牌
	private String type;//型号
	private double speed;//最大时速
	public Car() {
	}
	public Car(String brand, String type, double speed) {
		this.brand = brand;
		this.type = type;
		this.speed = speed;
	}
	public String getBrand() {
		return brand;
	}
	public void setBrand(String brand) {
		this.brand = brand;
	}
	public String getType() {
		return type;
	}
	public void setType(String type) {
		this.type = type;
	}
	public double getSpeed() {
		return speed;
	}
	public void setSpeed(double speed) {
		this.speed = speed;
	}
	@Override
	public String toString() {
		return "Car [brand=" + brand + ", type=" + type + ", speed=" + speed + "]";
	}
}


package com.lzl.spring.entity;
 
public class Person {
	private Integer id;
	private String name;
	private Car car;
	
	public Person(Integer id, String name) {
		this.id = id;
		this.name = name;
	}
	public Person() {
	}
	public Person(Integer id, String name, Car car) {
		this.id = id;
		this.name = name;
		this.car = car;
	}
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Car getCar() {
		return car;
	}
	public void setCar(Car car) {
		this.car = car;
	}
	@Override
	public String toString() {
		return "Person [id=" + id + ", name=" + name + ", car=" + car + "]";
	}
}

定义 JavaConfig 类对于一个 POJO 类，在类上使用@Configuration 注解，将会使当前类作为一个 Spring 的容器来使用，用于完成 Bean 的创建。在该 JavaConfig 的方法上使用@Bean，将会使一个普通方法所返回的结果变为指定名称的 Bean 实例。


package com.lzl.spring.entity;
 
import org.springframework.beans.factory.annotation.Autowire;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
 
//该注解表示这个类为javaConfig类
@Configuration
public class MyConfig {
	//该注解表示：向容器中注册一个叫做myCar的对象
	@Bean("myCar")
	public Car getCar() {
		return new Car("保时捷","911",300);
	}
	//该注解表示：向容器中注册一个叫做person的对象
	//并且通过byType的方式注入car
	@Bean(name="person",autowire=Autowire.BY_TYPE)
	public Person getPerson() {
		return new Person(1001,"望穿秋水见伊人");
	}
}

xml文件只需要添加自动扫描包配置


<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context.xsd
    ">
 
	<context:component-scan base-package="com.lzl.spring" />
 
</beans>

测试类


package com.lzl.spring.test;
 
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
 
import com.lzl.spring.entity.Car;
import com.lzl.spring.entity.Person;
 
public class SpringTest {
	@Test
	public void test1() {
		//读取配置文件
        ApplicationContext ctx=new ClassPathXmlApplicationContext("spring-config.xml");
        Car car = ctx.getBean("myCar", Car.class);
        System.out.println(car);
        Person person = ctx.getBean("person", Person.class);
        System.out.println(person);
	}
}

控制台输出