Question

我有一个名为InjectionTest的bean，它用@Component注释。当我在控制器内自动装配这个bean时，它工作正常。但是当我尝试在另一个带有@Component注释的类中使用它时，autowire不起作用，我得到一个空指针异常。有任何想法吗？

InjectionTest类

@Component
public class InjectionTest {

    private String word;

    public String getWord() {
        return "test";
     }

     public void setWord(String word) {
       this.word = word;
     }
}

下面是控制器类方法，它可以正常工作

@Controller
@CrossOrigin(origins = "*")
public class UserController {

    @Autowired
    AppConfig appConfig;

    @Autowired
    InjectionTest injectionTest;

    @RequestMapping(value = "/api/user/authentication", method = RequestMethod.POST)
    @ResponseBody
    public String authentication(HttpServletResponse res, @RequestParam Map<String, String> allRequestParams,
            HttpServletRequest req) {

        //I dont get an exception in the below line it works fine..
        System.out.println(injectionTest.getWord());
        ....
    }
}

下面是我想要自动装配InjectionTest类并在创建时获取空指针异常的组件......

@Component
public class HelloComponent {

    @Autowired
    InjectionTest injectionTest;

    public HelloComponent(){
    //I get null pointer exception in the below line.
        injectionTest.getWord();
    }

}

严重：StandardWrapper.Throwable org.springframework.beans.factory.BeanCreationException：错误创建名为＆＃39; helloComponent＆＃39;的bean在文件中定义 [C：\ Repo.metadata.plugins \ org.eclipse.wst.server.core \ TMP3 \ wtpwebapps \ AdaRvmWeb \ WEB-INF \类\ TR \ COM \ simroll \阿达\ RVM \网络\实体\ HelloComponent.class] ： bean的实例化失败;嵌套异常是 org.springframework.beans.BeanInstantiationException：失败实例化[tr.com.simroll.ada.rvm.web.entity.HelloComponent]：构造函数抛出异常;嵌套异常是显示java.lang.NullPointerException

我真的很困惑。创作时是否有订单或其他内容。如果是这样，我该如何解决这个问题呢？感谢..

从spring mvc中的另一个@Component注释类中自动装配@Component注释类

0 个答案: