Java 错误：构造函数未定义 (2)

Question

问题：我的重载构造函数是未定义的，即使我在做正确的事情（我认为是这样？）。

源代码：

class Book { 
    String section;
    float subject2;
    char section2, author;
    int subject, author2, year;

Book(String section, int subject, char author, int author2, int year) { 
    this.section = section;
    this.subject = subject;
    this.author = author;
    this.author2 = author2;
    this.year = year;
}
Book(char section2, float subject2, char author, int author2, int year) {
    this.section2 = section2;
    this.subject2 = subject2;
    this.author = author;
    this.author2 = author2;
    this.year = year;
}
void displayData() {
    System.out.println(section + subject + " ." + author + author2 + " " + year);
}
void displayData2() {
    System.out.println(section2 + subject2 + " ." + author + author2 + " " + year);
}}
public class TestBook {
  public static void main(String[] args) {
    Book book1 = new Book("LB", 2395, "C", 65, 1991);
    Book book2 = new Book("E", 185.86, "P", 277, 2010);
    book1.displayData();
    book2.displayData2();
    s.close();  
}}

如果打扰，请为长度道歉。 感谢您的帮助！

Answer 1

你打电话时 ：

Book book2 = new Book("E", 185.86, "P", 277, 2010);

如果要使用 char 调用第二个构造函数，请将“E”更改为“E”，否则“E”是 String 对象。 领域author （将“P”更改为“P”）

顺便说一句，您可以覆盖toString()方法，而不是创建displayData() toString()方法：

@Override
public String toString() {
    return "your string with information";
}

所以你可以调用这个方法：

System.out.println(book.toString());
System.out.println(book); // The same thing ! It will call the toString() method