如何使用该元素的字段值在ArrayList中查找元素？

I am writing a program in Java which accepts user-inputted String in one class.

我正在用Java编写一个程序,它在一个类中接受用户输入的String。

On a separate class, I have an array-list of class type 'Item' which contains elements of type String (itemName), int, and double. I was wondering if there was a way to either convert the user-inputted String to an object of type 'Item' (I've heard it's difficult), or if there was a way to access the individual String element itemName of the array-list to compare it to the user-inputted String.

在一个单独的类中,我有一个类类型'Item'的数组列表,它包含String(itemName),int和double类型的元素。我想知道是否有办法将用户输入的String转换为'Item'类型的对象(我听说很难),或者如果有办法访问数组的单个String元素itemName-列表将其与用户输入的字符串进行比较。

Item.java

public class Item {
    private String name;
    private int monetaryValue;
    private double weight;

    // Getters and Setters
    // ...

    // Other methods
    // ...
}

3 个解决方案

#1

I would not use Reflection here: it's using a bazooka for killing a mosquito. I'd rather use plain Java.

我不会在这里使用反射:它使用火箭筒杀死蚊子。我宁愿使用普通的Java。

Check this example below:

请查看以下示例:

List<Item> myList = new ArrayList<Item>();
String userInputValue;

// * Add some items to myList
// ...

// * Get user input value
// ...

// * Access the array list
int len=myList.size();
for(int i=0; i<len; i++) {
    if (myList.get(i).getItemName().equals(userInputValue)) {
        // Do something ...
    }
}

#2

To create an Item from user input, you can do:

要从用户输入创建项目,您可以执行以下操作:

String input1;
String input2;
String input3;

// Assign user input to input1, input2, input3

String itemName = input1;
int data2 = Integer.parseInt(input2);
double data3 = Double.parseDouble(input3);

Item myItem = new Item(itemName, data2, data3);

To access elements from array list, you can do:

要从数组列表中访问元素,您可以执行以下操作:

List<Item> items;
String input;

// Populate items

// Assignment user input to "input" variable.

for (Item item : items) {
    if (item.getItemName().equals(input)) {
        // Do something...
    }
}

#3

You can of course build Item objects from user input if you define an input format like [name:string] [i:int] [d:double] (example : john 5 3.4). You then just have to split this String and use Integer.parseInt and Double.parseDouble to parse the two last arguments.

如果您定义输入格式,如[name:string] [i:int] [d:double](例如:john 5 3.4),您当然可以从用户输入构建Item对象。然后,您只需要拆分此String并使用Integer.parseInt和Double.parseDouble来解析最后两个参数。

#1