修复在公共类java中找不到符号

public class Book {

    //variables
    private String title = "";
    int isbn = 0;
    int quantity = 0;

    public Book(String title, int isbn, int quantity) throws Exception {
        this.setTitle(title);
        this.setIsbn(isbn);
        this.setQuantity(quantity);
    }

    //toString method that return with book information
    public String toString() {
        String s = "";

        s = "title:" + this.title;
        s = s + "\nIsbn:" + this.isbn;
        s = s + "\nQuantity:" + this.quantity;

        return s;
    }

    public void setTitle(String newTitle) throws Exception {
        if ((newTitle != null)) {
            this.title = newTitle;
        } else {
            BookException be = new BookException();
            be.setMessage("wrong input, title should not be blank.");
            throw be;
        }
    }

    public String getTitle() {
        return this.title;
    }
}

why there was no symbol in the code this.setIsbn(isbn) and this.setQuantity(quantity)

为什么代码中没有符号this.setIsbn(isbn)和this.setQuantity(quantity)

1 个解决方案

#1

Because your class do not have methods setIsbn and setQuantity you have to create them and then only you can use them

因为您的类没有方法setIsbn和setQuantity,所以您必须创建它们,然后才能使用它们

public void setIsbn(int isbn) {
   this.isbn = isbn;
}

public void setQuantity(int quantity) {
   this.quantity = quantity;
}

And on similar lines you should also have getters for these

在类似的路线上你也应该有吸气剂

public int getIsbn() {
   return this.isbn;
}

public int getQuantity() {
   return this.quantity;
}

#1