我正在尝试连接以运行查询以获取 MongoDB 中的所有记录，然后将记录转换为引用对象类型的列表，我将其作为调用类的泛型。代码运行良好并在 Eclipse 中实现了预期的结果，但在 maven build 期间出现编译错误，maven 和 eclipse 都引用相同的 JDK(1.8)。有人可以帮我解决这个问题吗

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();
        }
    }

}  

日志:-

[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

关于复制同一存在的完整消息:-

更新:显式类型转换对象变量有效，但我仍然需要了解如何？

  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();
        }
    }

最佳答案

当您尝试将对象转换为 report 的特定 Type 时，请尝试更改

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

到

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

关于java - 不兼容的类型 : inference variable T has incompatible bounds equality constraints: capture#1 of ? 扩展了 java.lang.Object，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/46460874/