如何在不同类中多次注入时获得一个依赖实例？

Question

我需要获取 OwnerService 的一个实例，因为在 Dataloader class 中我将一些数据加载到该实例，而在 OwnerController class 中我必须获取加载的数据。但是在 OwnerController 中没有数据。我打印出实例并收到不同的实例 ID

数据加载器class

public class DataLoader implements CommandLineRunner {
   private final OwnerService ownerService;
   public DataLoader() {
      ownerService = new OwnerServiceMap();
   }
   @Override
   public void run(String... args) throws Exception {
      System.out.println(ownerService);
   }
}

@RequestMapping("/owners")
@Controller
public class OwnerController {
    private final OwnerService ownerService;

    public OwnerController(OwnerService ownerService) {
        this.ownerService = ownerService;
    }

    @GetMapping({"", "/", "/index"})
    public String ownersIndex(Model model) {
        System.out.println(ownerService);
        model.addAttribute("owners", ownerService.findAll());
        return "owners/index";
    }
}

我需要一个 Bean 实例注入多个 classes.

Answer 1

在您的 class DataLoader 中，您没有注射 OwnerService。相反，构造函数直接创建 class OwnerServiceMap 的实例（大概是实现接口 OwnerService 的 class）：

public DataLoader() {
    ownerService = new OwnerServiceMap();
}

相反，将其注入 DataLoader，方法与在 OwnerController:

中完全相同

public DataLoader(OwnerService ownerService) {
    this.ownerService = ownerService;
}

如何在不同类中多次注入时获得一个依赖实例？

How to get one instance of dependency while it injected several times in different classes?

java

spring

dependency-injection

spring-boot

如何在不同 类 中多次注入时获得一个依赖实例？

How to get one instance of dependency while it injected several times in different classes?

java

spring

dependency-injection

spring-boot

如何在不同类中多次注入时获得一个依赖实例？