java - Java / 我的班级没有看到对方？

Question

我有两节课：

模型/用户.java

package Model;

public class User {
    public int id;
    public String firstName;
    public String lastName;

    User( int id, String firstName, String lastName )
    {
        this.id = id;
        this.firstName = firstName;
        this.lastName = lastName;
    }
}

和

存储库/UserRespository.java

package Repositories;
import Model.User;

public class UserRepository 
{
    public User CreateUser( int id, String firstName, String lastName )
    {
        User newUser = new User( id, firstName, lastName );
        return newUser;
    }

    public User GetUserById()
    {
        User user = new User( id, firstName, lastName );
        return user;
    }
}

我收到这些错误：

firstName cannot be resolved    MVCExample/src/Repositories UserRepository.java line 14 1372765344696   53

id cannot be resolved   MVCExample/src/Repositories UserRepository.java line 14 1372765344695   52

lastName cannot be resolved MVCExample/src/Repositories UserRepository.java line 14 1372765344696   54

The constructor User(int, String, String) is not visible    MVCExample/src/Repositories UserRepository.java line 8  1372765344695   51

我究竟做错了什么？

Answer 1

您应该将类​​的构造函数User设为public.

Answer 2

User user = new User( id, firstName, lastName );

您在没有声明的情况下使用它id，firstName并且lastName

Answer 3

在这部分代码中：

public User GetUserById()
{
    User user = new User( id, firstName, lastName );
    return user;
}

您没有声明 id、firstName 和 lastName，如果您希望它们可用，则需要将它们声明为实例变量，此外，在这部分：

User( int id, String firstName, String lastName )
{
    this.id = id;
    this.firstName = firstName;
    this.lastName = lastName;
}

您需要将您的构造函数声明为public。

Answer 4

将您的方法更改为

 public User GetUserById(int id, String firstName, String lastName)
    {
        User user = new User( id, firstName, lastName );
        return user;
    }

Answer 5

将您的 User 类构造函数设为公开，例如：

public User( int id, String firstName, String lastName )
    {
        this.id = id;
        this.firstName = firstName;
        this.lastName = lastName;
    }