小编rob*_*del的帖子

在课堂上我有一个公共属性TissueCompartments:

class Diver {
public:
    TissueCompartments tissueCompartments[16];
    Diver();
    Diver(const Diver& orig, TissueCompartments tissueCompartments[16]);
    virtual ~Diver();
};

我有一个构造函数

Diver::Diver(const Diver& orig, TissueCompartments tissueCompartments[16]) {
    this->tissueCompartments=tissueCompartments;
}

我得到这个错误:错误:'TissueCompartments*'与'TissueCompartments [16]'分配不兼容的类型

我在控制器中使用Optional

@GetMapping(value = "/address/{id}")
public ResponseEntity<Addresses> getAddressById(@PathVariable("id") Integer id) {

    Optional<Address> address = addressService.getAddressById(id);
    return new ResponseEntity(address.get(), address.isPresent() ? HttpStatus.OK : HttpStatus.NOT_FOUND);
}

实际上,如果没有价值,我会得到

java.util.NoSuchElementException: No value present
    at java.util.Optional.get(Optional.java:135) ~[na:1.8.0_131]

不确定这是否是管理事物的好方法.

有什么好的实践吗？

我试着同时读取文件并返回行数

ExecutorService executor = Executors.newFixedThreadPool(2);
FutureTask<Integer> futureOne = new FutureTask<Integer>(new Calcul1());
FutureTask<Integer> futureTwo = new FutureTask<Integer>(new Calcul2());
executor.execute(futureOne);
executor.execute(futureTwo);
while (!(futureOne.isDone() && futureTwo.isDone())) {

}

System.out.println(futureOne.get() + futureTwo.get());
executor.shutdown();

这工作得很好但我发现如果我读取文件1和文件2后更快...所以我没有得到任何性能提升futureTash

为什么？

我有两个类Drug和medicalDrawer.

我搜索了一种方法来获取所有medicalDrawer未使用的内容Drug

@Entity
public class Drug {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long drugId;

    @OneToOne
    private MedicalDrawer medicalDrawer;
}

@Entity
public class MedicalDrawer {

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long medicalDrawerId;

    private String name;
}