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
