Question

目前正在使用 jgrasp 编写一个小程序，在同一目录中使用两个不同的文件。在一个文件中，我有一个公共类，其中包含几个名为Employee的公共构造函数。在另一个文件中，我有一个用于实现Employee类的类。我无法构建这个程序 - 编译器基本上告诉我，这些提供的构造函数不存在（参见下面的代码）。因此我制作的每个构建都失败了

我的Employee类中的构造函数具有公共访问权限，据我所知正确命名。我是一个C＃的家伙，所以我不知道我是不是因为我的性格或什么而没有看到这个问题。我正在学习Java课程。

这是我的员工类：

public class Employee
{
   // description: class representation of an employee. 

   // variable declarations
   String name = "", department = "", position = "";
   int idNumber = 0;

   // constructors
   public Employee(String n, String d, String p, int id)
   {
      // full constructor
      this.name = n; 
      this.department = d; 
      this.position = p; 

      if (id > -1) this.idNumber = id; 
      else this.idNumber = 0; 
   }
   public Employee(String n, int id)
   {
      // partial constructor (name and id)
      this.name = n; 

      if (id > -1) this.idNumber = id; 
      else idNumber = 0; 

      this.department = ""; 
      this.position = ""; 
   }
   public Employee()
   {
      // default constructor
      this.name = ""; 
      this.department = ""; 
      this.position = ""; 
      this.idNumber = 1;
   }

   // accessors
   public String getName() { return name; }
   public String getDepartment() { return department; }
   public String getPosition() { return position; }
   public int getID() { return idNumber; }

   // mutators
   public void setName(String newName) { name = newName; }
   public void setDepartment(String newDepartment) { department = newDepartment; }
   public void setPosition(String newPosition) { position = newPosition; }
   public void setID(int newID) { idNumber = newID; }
}

这是我的实现类：

public class ChallengeImplementor
{
   public static void main(String[] args)
   {
      // create instance-variables for constructors
      String e1_name = "Susan Meyers", e2_name = "Mark Jones"; 
      string e1_department = "Accounting"; 
      string e1_position = "Vice President"; 
      int e1_ID = 47899, ew_ID = 39119; 

      // create several employee objects to prove they work. 
      Employee e1 = new Employee("Susan Meyers", "Accounting", "Vice President", 47899),  // created one with full constructor
               e2 = new Employee("Mark Jones", 39119),                                    // ... partial constructor
               e3 = new Employee();                                                       // ... default constructor

      // set values for e2 that weren't covered in partial constructor
      e2.setDepartment("IT"); 
      e2.setPosition("Programmer"); 

      // set values for e3
      e3.setName("Joy Rogers"); 
      e3.setDepartment("Manufacturing"); 
      e3.setPosition("Engineer"); 
      e3.setID(81774); 

      // display all three employees
      System.out.println("Name\t\tID\t\tDepartment\t\tPosition"); 
      System.out.println("----------------------------------------------------------------------");
      System.out.println(e1.getName() + "\t" + e1.getID() + "\t\t" + e1.getDepartment() + "\t\t" + e1.getPosition()); 
      System.out.println(e2.getName() + "\t" + e2.getID() + "\t\t" + e3.getDepartment() + "\t\t" + e2.getPosition()); 
      System.out.println(e3.getName() + "\t" + e3.getID() + "\t\t" + e3.getDepartment() + "\t\t" + e3.getPosition()); 
   }
}

Answer 1

也许您的导入声明丢失了。将其添加到类名称正下方的类顶部。

import {full package name}.Employee;

Answer 2

看看这个： e1_department和e1_position应该是字符串对象，但在 java 中没有字符串（请注意名称小写）

通过执行以下操作来修复拼写错误：

String e1_department = "Accounting";
String e1_position = "Vice President";

之后，代码按预期运行：

输出：

Answer 3

我拿了代码并运行了你的主要功能并得到了这个回复：

Traceback (most recent call last):
  File "/usr/bin/subliminal", line 5, in <module>
    from pkg_resources import load_entry_point
  File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 3080, in <module>
    @_call_aside
  File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 3066, in _call_aside
    f(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 3093, in _initialize_master_working_set
    working_set = WorkingSet._build_master()
  File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 651, in _build_master
    ws.require(__requires__)
  File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 952, in require
    needed = self.resolve(parse_requirements(requirements))
  File "/usr/lib/python3/dist-packages/pkg_resources/__init__.py", line 839, in resolve
    raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'argparse' distribution was not found and is required by stevedore

这里看起来不错。你能检查一下你是否正确导入了包裹吗？

其次，我在主函数的第二个和第三个字段上看到两个错误：这些字段被声明为带有小s的字符串，应该是String。

Answer 4

我刚刚尝试编译你的程序，它最初没有工作。原因是您在ChallengeImplementor字段中使用了原始字符串类型：

  string e1_department = "Accounting"; 
  string e1_position = "Vice President";

一旦我将其更改为String，它编译并正常工作： screenshot。右键单击ChallengeImplementor.class并将其作为Java Application

启动

希望这有帮助

Answer 5

好吧，我是一个完全白痴。不知何故，Employee.java文件被移出同一目录。我认为jGrasp意外地将它保存在其他地方，即使这两个文件最初都是在哪里。

我修复了String问题 - 这实际上只是我试图执行的测试，而且从来不需要代码。

构造函数拒绝使用

5 个答案: