英文:
Why does Java throw NullPointerException using HashMap with Dagger?
问题
首先，我创建Dagger Component和Module。
@Singleton
@Component(modules = {UploadModule.class})
public interface UploadComponent {
void inject(UploadS3ToMap requestHandler);
}
Module：
private Map<String, String> uploadMap = new HashMap<String, String>();
@Singleton
@Provides
Map<String, String> getUploadMap() {
return uploadMap;
}
然后尝试在我的类中使用它：
@Inject
Map<String,String> getUploadMap;
getUploadMap.put("test", "testIssue");
return getUploadMap.toString();
但我遇到了异常：nulljava.lang.NullPointerException
这里有什么问题？
英文:
First I create Dagger Component and Module.
@Singleton
@Component(modules = {UploadModule.class})
public interface UploadComponent {
void inject(UploadS3ToMap requestHandler);
}
Module:
private Map<String, String> uploadMap = new HashMap<String, String>();
@Singleton
@Provides
Map<String, String> getUploadMap() {
return uploadMap;
}
And than trying to use it in my Class:
@Inject
Map<String,String> getUploadMap;
getUploadMap.put("test", "testIssue");
return getUploadMap.toString();
And I have an Exception: nulljava.lang.NullPointerException
What is wrong with it?
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