Spring依赖注入的三种方式

1、 settter方法注入 以@Autowired注解为例，即把@Autowired注解标记在目标bean的引用bean的setter方法上。

@RestController
@RequestMapping("/abc")
public class AbcController {


    private AbcService abcService;

    @Autowired
    public void setAbcService(AbcService abcService) {
        this.abcService = abcService;
    }

    @GetMapping("/rateLimit")
    public  String  rateLimit(){

        System.out.println("start");
        abcService.printABC();
        return "abc";
    }

}

2.构造器注入

@RestController
@RequestMapping("/abc")
public class AbcController {


    private AbcService abcService;
    
    public AbcController(AbcService abcService) {
        this.abcService = abcService;
    }

    @GetMapping("/rateLimit")
    public  String  rateLimit(){

        System.out.println("start");
        abcService.printABC();
        return "abc";
    }

}

3.变量(filed) 注入

@RestController
@RequestMapping("/abc")
public class AbcController {

    @Autowired
    private AbcService abcService;
    

    @GetMapping("/rateLimit")
    public  String  rateLimit(){

        System.out.println("start");
        abcService.printABC();
        return "abc";
    }

}