Question

我正在尝试删除输入名称的地址簿条目，但我得到了 java：148错误：不兼容的类型 return fileToDelete.delete（）;

required: AddressBookEntry
found:    boolean

1错误

有问题的代码是：

    public class AddressBookDelegateImpl implements AddressBookDelegate {

    private File userHomeDir;

    private File addressBookDirectory;
    private String replaceSpacesWithUnderScores( String string ) {
        return string.replaceAll( " ", "_" ).toLowerCase();
    }

    public AddressBookEntry deleteAddressBookEntry( String name )
                              throws AddressBookDelegateException {

        try{
            String dname = replaceSpacesWithUnderScores( name );
            File fileToDelete = new File( addressBookDirectory, dname );
            return fileToDelete.delete() ;
        } catch(NullPointerException e) {
            throw new AddressBookDelegateException("Could not find the file", e);
        }
      }
     }

Answer 1

您的方法在其声明中返回并AddressBookEntry：

public AddressBookEntry deleteAddressBookEntry( String name )

而return语句说：

 return fileToDelete.delete() ;

您可能需要考虑将AddressBookEntry返回类型声明为boolean，如下所示：

public boolean deleteAddressBookEntry( String name )

Answer 2

File.delete()返回一个布尔值...

Answer 3

错误已经很好地描述了它。如果删除成功， delete 方法返回一个布尔值。因此，如果返回值为true，则应检查该值，然后返回已删除的AddressBookEntry。

Answer 4

在Java中，方法的返回类型在方法声明中定义。所以在你的例子中，你有：

   public AddressBookEntry deleteAddressBookEntry( String name )throws AddressBookDelegateException {

       try{
           String dname = replaceSpacesWithUnderScores( name );
           File fileToDelete = new File( addressBookDirectory, dname );
           return fileToDelete.delete() ; //this returns a boolean
       } catch(NullPointerException e) {
          throw new AddressBookDelegateException("Could not find the file", e);
       }
   }

因此，如果您不想更改返回方法，这可能就是您想要做的，那么您应该尝试使用此代码：

   public boolean deleteAddressBookEntry( String name )throws AddressBookDelegateException {

       try{
           String dname = replaceSpacesWithUnderScores( name );
           File fileToDelete = new File( addressBookDirectory, dname );
           return fileToDelete.delete() ; //this returns a boolean
       } catch(NullPointerException e) {
          throw new AddressBookDelegateException("Could not find the file", e);
       }
   }

这将返回fileToDelete.delete()方法的结果。

Answer 5

请修改你的方法deleteAddressBookEntry，如下所示：

public Boolean deleteAddressBookEntry(String name)
                throws AddressBookDelegateException {
            try {
                String dname = replaceSpacesWithUnderScores(name);
                File fileToDelete = new File(addressBookDirectory, dname);
                if(fileToDelete.exists())
                    return fileToDelete.delete();
            } catch (NullPointerException e) {
                throw new AddressBookDelegateException("Could not find the file", e);
            }
            return false;
        }

不兼容的类型？

5 个答案: