1. 注解注入

@Controller
public class TestController {
  @Autowired
  private TestService testService;
   
}

注解注入，一般是注入另一个bean

2. 构造器注入

@Controller
public class TestController {
   
  private final TestService testService;
   
  @Autowired
  public FooController(TestService testService) {
      this.testService = testService;
  }

}

构造器注入，配置bean一并配置constructor

3. setter注入

@Controller
public class TestController {
   
  private TestService testService;
   
  @Autowired
  public void setFooService(TestService testService) {
      this.testService = testService;
  }
}

Setter注入，配置property　

推荐使用构造器注入