1. 自动注入
   开启组件扫描，在需要注入的变量前加注解@Autowired

config.java

@Configuration
@ComponentScan(basePackages = "cn.tedu.demo")
public class Config {}

worker.java

@Component
public class Worker implements Serializable {
    private String name = "初号机";

    @Autowired
    public Saw saw;

    public void work(){
        System.out.println(name + "使用" + saw + "砍树" );
    }
}

saw.java

@Component
public class Saw implements Serializable {
    private String name = "三尖两刃刀";

    @Override
    public String toString() {
        return name;
    }
}

执行

    @Test
    public void testWorkerSaw(){
        Worker worker = ctx.getBean("worker",Worker.class);
        worker.work();
    }

2. set方法注入
   如果set方法中有逻辑，可以进行运算

@Component
public class Worker implements Serializable {
    private String name = "初号机";
    public Saw saw;

    @Autowired
    public void setSaw(Saw saw){
        this.saw = saw;
    }
    public void work(){
        System.out.println(name + "使用" + saw + "砍树" );
    }
}

其他代码不变