不兼容的類型：推理變量T具有不兼容的邊界相等約束：capture＃1 of？ extends java.lang.Object

Question

我想連接運行一個查詢來獲取MongoDB中的所有記錄，然後將記錄轉換爲引用對象類型的列表，我將它作爲我的調用類的泛型。代碼運行良好，在Eclipse中實現了期望的結果，但在maven構建過程中出現了編譯錯誤，maven和eclipse都引用了相同的JDK（1.8）。有人可以幫我解決這個問題

public class MongoPersistenceImpl<T> { 

MongoDatabase database=(MongoDatabase)MongoConnectImpl.getInstance().getConnection(); 

public List<T> getAll(T modelObject){ 
     MongoCollection<Document> collection=database.getCollection(MongoConnectImpl.MONGO_COLLECTION); 
     List<T> reportList=new ArrayList<>(); 
     Gson gson=new Gson(); 
     MongoCursor<Document> cursor = collection.find().iterator(); 
     try { 
      while (cursor.hasNext()) { 
       T report=gson.fromJson(cursor.next().toJson(),modelObject.getClass()); 
       reportList.add(report); 
      } 
      return reportList; 
     }catch(Exception e){ 
      CatsLogger.printLogs(3, "30016", e, MongoPersistenceImpl.class,new Object[]{"get all"}); 
      return null; 
     } finally { 
      cursor.close(); 
     } 
    } 

} 

日誌： -

[ERROR] COMPILATION ERROR : 
[INFO] ------------------------------------------------------------- 
[ERROR] incompatible types: inference variable T has incompatible bounds 
    equality constraints: capture#1 of ? extends java.lang.Object 
    upper bounds: T,java.lang.Object 

上重現同一個幸福完整的消息： -

UPDATE：明確地類型轉換一個對象變量工作，但我仍然編輯瞭解如何？

public List<T> getAll(T modelObject){ 
     MongoCollection<Document> collection=database.getCollection(MongoConnectImpl.MONGO_COLLECTION); 

     List<T> reportList=new ArrayList<T>(); 
     Gson gson=new Gson(); 
     MongoCursor<Document> cursor = collection.find().iterator(); 
     try { 
      while (cursor.hasNext()) { 
       Object rep=gson.fromJson(cursor.next().toJson(),modelObject.getClass()); 
       T report=(T)rep;//explicit type cast 
       reportList.add(report); 
      } 
      return reportList; 
     }catch(Exception e){ 
      CatsLogger.printLogs(3, "30016", e, MongoPersistenceImpl.class,new Object[]{"get all"}); 
      return null; 
     } finally { 
      cursor.close(); 
     } 
    } 

Answer 1

當你試圖對象轉換的report特定Type，嘗試改變

T report = gson.fromJson(cursor.next().toJson(), modelObject.getClass()); 

到

T report = gson.fromJson(cursor.next().toJson(), (java.lang.reflect.Type) modelObject.getClass());