java - 如何将 Cucumber 中的 DataTable 转换为对象列表？

Question

原标题:What does scalar in Cucumber DataTables in Java?

来自 this引用:

Java provides several scalar types. These include primitive numeric types, plus boolean and char.

Every scalar (primitive) type has an associated wrapper class or reference type.

阅读javadocs:

/**
  * Converts the table to a List.
  *
  * If {@code itemType} is a scalar type the table is flattened.
  *
  * Otherwise, the top row is used to name the fields/properties and the remaining
  * rows are turned into list items.
  *
  * @param itemType the type of the list items
  * @param <T>      the type of the list items
  * @return a List of objects
  */
public <T> List<T> asList(Class<T> itemType) {
    return tableConverter.toList(this, itemType);
}

/**
  * Converts the table to a List of List of scalar.
  *
  * @param itemType the type of the list items
  * @param <T>      the type of the list items
  * @return a List of List of objects
  */
public <T> List<List<T>>> asLists(Class<T> itemType) {
    return tableConverter.toLists(this, itemType);
}

但是，我能够在 asList() 中传递 String.class:

List<String> list = dataTable.asList(String.class);

字符串在 Java 中不是原语。我想澄清一下“标量”在这种情况下的含义。

Answer 1

引用生成的代码片段:

// For automatic transformation, change DataTable to one of
// List<YourType>, List<List<E>>, List<Map<K,V>> or Map<K,V>.
// E,K,V must be a scalar (String, Integer, Date, enum etc)

Cucumber javadoc 中的“标量”可能被错误地统称为原语(即标量)的关联包装类。

---

在下面的示例中，asList() 按照文档继续创建用户定义的费用对象列表:

Otherwise, the top row is used to name the fields/properties and the remaining rows are turned into list items.

我观察到以下情况:

1. 特征文件中的顶行(标题)必须匹配字段 对象的名称。
2. 构造函数可以接受所有字段作为参数。

用户定义对象(非标量):

public class Expense {

    private String name = null;
    private String amount = null;
    private String frequency = null;

    public Expense(String name, String amount, String frequency) {
        this.name = name;
        this.amount = amount;
        this.frequency = frequency;
    }

    // Getters and setters
}

特征:

When I Enter My Regular Expenses
  | name        | amount | frequency     |
  | Electricity |   5500 | Monthly       |
  | Water       |    900 | Weekly        |
  | Internet    |   1900 | Every 2 Weeks |
  | Cable TV    |    555 | Daily         |

步骤定义:

@When("^I Enter My Regular Expenses$")
public void I_Enter_My_Regular_Expenses(DataTable dataTable) throws Throwable {
  List<Expense> expenseList = dataTable.asList(Expense.class);

  for (Expense expense : expenseList) {
    System.out.println(expense);
  }

  // Here, asList() creates a List of Expense objects.
}

输出: