Question

我有以下内容：

@Service(DropboxService.NAME)
public class DropboxServiceBean implements DropboxService {

    @Inject
    private CustomConfig customConfig;


    private final String ACCESS_TOKEN = customConfig.getDropboxAppToken();
    DbxRequestConfig config = new DbxRequestConfig("dropbox/java-tutorial", "en_US");
    DbxClientV2 client = new DbxClientV2(config, ACCESS_TOKEN);

有谁知道我如何才能首先加载customConfig.getDropboxAppToken();的值。我一直收到以下错误：

Caused by: org.springframework.beans.factory.BeanCreationException:
Error creating bean with name 'myApp_DropboxService' defined in URL
[jar:file:/E:/Cuba/myApp/deploy/tomcat/webapps/app-core/WEB-INF/lib/app-core-0.1-SNAPSHOT.jar!/com/daryn/myApp/service/DropboxServiceBean.class]:
Instantiation of bean failed; nested exception is
org.springframework.beans.BeanInstantiationException: Failed to
instantiate [com.daryn.myapp.service.DropboxServiceBean]: Constructor
threw exception; nested exception is java.lang.NullPointerException

我正在尝试的当前代码

错误：使用名称＆＃39; ecosmart_BackupService＆＃39;创建bean时出错：通过字段＆lt; dropboxService＆＃39;表达的不满意的依赖关系嵌套异常是org.springframework.beans.factory.BeanCreationException：使用名称＆＃39; ecosmart_DropboxService创建bean时出错＆＃39;：init方法的调用失败;嵌套异常是java.lang.NullPointerException

@Service(DropboxService.NAME)
public class DropboxServiceBean implements DropboxService {

    @Inject
    private CustomConfig customConfig;


    private String ACCESS_TOKEN = "";
    DbxRequestConfig config;
    DbxClientV2 client;



    @PostConstruct
    public void postConstruct() {
        System.out.println("**************Running post construct");
        ACCESS_TOKEN = customConfig.getDropboxAppToken();
        config = new DbxRequestConfig("dropbox/java-tutorial", "en_US");
        client = new DbxClientV2(config, ACCESS_TOKEN);
    }

Answer 1

Spring仅在构造对象后注入字段，并且在您的情况下public static void MyMethod<T>(this IDriver<T> driver) where T : IDriverConfiguration { }在此之前被初始化。

你需要创建一个构造函数并在构造函数中注入你的bean，如下所示：

ACCESS_TOKEN

Answer 2

嗯，经过多次捣乱，这是我的绝佳解决方案。我不知道为什么CustomConfig不会首先初始化......

@Service(DropboxService.NAME)
public class DropboxServiceBean implements DropboxService {        


    @Inject
    private CustomConfig customConfig;


    private String ACCESS_TOKEN = "";
    DbxRequestConfig config =new DbxRequestConfig("dropbox/java-tutorial", "en_US");
    DbxClientV2 client;

    public static boolean isInitiated = false;

    public void generateDbxClient(){
        ACCESS_TOKEN = customConfig.getDropboxAppToken();
        client = new DbxClientV2(config, ACCESS_TOKEN);
    }

    @Override
    @Transactional
    public void uploadFile(FileDescriptorExt file, String path) {

        if(isInitiated==false){
            System.out.println("generating client");
            generateDbxClient();
            isInitiated=true;
        }

Bean实例化顺序

2 个答案: