Spring框架中IoC容器与DI依赖注入教程

package old;
/**
 * 构建“车”
 */
public class Car {
    private Framework framework;
    public Car(int size) {
        framework = new Framework(size);
    }
    public static void main(String[] args) {
        int size = 15;
        // 构建并运行车
        Car car = new Car(size);
        car.init();
    }
    // 运行
    public void init() {
        System.out.println("Car init.");
        // 依赖 framework init() 方法
        framework.init();
    }
}

package old;
/**
 * 车身
 */
public class Framework {
    private Bottom bottom;
    public Framework(int size) {
        bottom = new Bottom(size);
    }
    public void init() {
        System.out.println("Framework init.");
        // 依赖 Bottom:init()
        bottom.init();
    }
}

package old;
/**
 * 底盘
 */
public class Bottom {
    private Tire tire;
    public Bottom(int size) {
        tire = new Tire(size); // 自己（创）造
    }
    public void init() {
        System.out.println("Bottom init.");
        // 依赖：Tire:init()
        tire.init();
    }
}

package old;
/**
 * 轮胎
 */
public class Tire {
    // 尺寸
    private int size = 17;
    // 材质...
    // 花纹...
    // 颜色...
    // ...
    public Tire(int size) {
        this.size = size;
    }
    public void init() {
        System.out.println("Tire size:" + size);
    }
}

package v2;
public class TireV2 {
    private int size = 17;
    private String color = "黑色";
    public TireV2(int size, String color) {
        this.size = size;
        this.color = color;
    }
    public void init() {
        System.out.println("Tire v2 size:" + size);
    }
}

package v2;
public class BottomV2 {
    private TireV2 tireV2;
    public BottomV2(TireV2 tireV2) {
        this.tireV2 = tireV2;
    }
    public void init() {
        System.out.println("Bottom v2 init.");
        tireV2.init();
    }
}

package v2;
public class FrameworkV2 {
    private BottomV2 bottomV2;
    public FrameworkV2(BottomV2 bottomV2) {
        this.bottomV2 = bottomV2;
    }
    public void init() {
        System.out.println("Framework v2 init.");
        bottomV2.init();
    }
}

package v2;
/**
 * 控制反转的车
 */
public class CarV2 {
    private FrameworkV2 frameworkV2; // 依赖
    public CarV2(FrameworkV2 frameworkV2) {
//        frameworkV2 = new FrameworkV2(); // 自己创建（自己控制对象的生命周期）
        this.frameworkV2 = frameworkV2; // Car 构造方法不会在创建
    }
    public void init() {
        System.out.println("Car v2 init.");
        // 依赖 framework:init()
        frameworkV2.init();
    }
}

package v2;
public class App {
    public static void main(String[] args) {
        // 程序调用
        int size = 15;
        String color = "红色";
        TireV2 tireV2 = new TireV2(size, color);
        BottomV2 bottomV2 = new BottomV2(tireV2);
        FrameworkV2 frameworkV2 = new FrameworkV2(bottomV2);
        CarV2 carV2 = new CarV2(frameworkV2);
        carV2.init();
    }
}