Abc类：
@Component
public class Abc {
private int a;
private int b;
public void Say(){
System.out.println("输出啊");
}
public Abc(int a) {
this.a = a;
System.out.println("构造A");
}
public Abc(int a, int b) {
this.a = a;
this.b = b;
System.out.println("构造B");
}
}
Bab类:

@Component
public class Bab {
@Autowired
private Abc abc;
public void setAbc(Abc abc) {
System.out.println("注入开始");
this.abc = abc;
}
public void say(){
abc.Say();
}
}