Question

如果我有一些IF语句，我怎么能返回1个值？

例如，当我选择Shopify时，它调用一个新方法，允许我输入一些需要凭据的控制台，然后将所有典型数据附加到1个String中并将该String（test）返回给Main类。如果我选择Bigcommerce，它会调用几乎相同的方法，并将Biggcomerce所需的所有凭据也附加到1 String（test2）中。但在这种情况下，public String credentailsCollector（）应该返回test2。

我该怎么做？感谢。

public class CartCredentialsCollector {
//it should return something like this: 
//store_url=https://test.myshopify.com&apiKey=myapikey&apiPassword=myapipassword

public String credentailsCollector() throws IOException {

    BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));

    System.out.println("Do you want to connect a new shopping cart ('yes'/'no')");
    String newConnection = bufferedReader.readLine();
    if (newConnection.equals("no")) {
        bufferedReader.close();
    } else {
        System.out.println("Specify your shopping cart. It works with Shopify and Bigcommerce only");
        String newShoppingCart = bufferedReader.readLine();
        if (newShoppingCart.equals("Shopify")) {
            ShopifyCredentialsHandler sch = new ShopifyCredentialsHandler();
            String test = sch.shopifyCredentialsHandler();
        }
        else if (newShoppingCart.equals("Bigcommerce")) {
        BigcommerceCredentialsHandler bch = new BigcommerceCredentialsHandler();
        String test2 = bch.bigcommerceCredentialsHandler()
        }

        else {
            System.out.println("This method works with Shopify and Bigcommerce. Try to connect a Shopify or Bigcommerce store.");
            bufferedReader.close();
        }
    }
    // Here I need to return test (in case I choose "Shopify") or test2 (in case I choose "Bigcommerce"). How can I do that?
    }
}

Answer 1

你应该在你的if语句之前声明test或者多次返回 - 每个都在一个内部。

Answer 2

您可以使用方法范围String变量并设置其值而不是两个不同的String变量。像这样：

public class CartCredentialsCollector {
//it should return something like this: 
//store_url=https://test.myshopify.com&apiKey=myapikey&apiPassword=myapipassword

public String credentailsCollector() throws IOException {
    String test = null;
    BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));

    System.out.println("Do you want to connect a new shopping cart ('yes'/'no')");
    String newConnection = bufferedReader.readLine();
    if (newConnection.equals("no")) {
        bufferedReader.close();
    } else {
        System.out.println("Specify your shopping cart. It works with Shopify and Bigcommerce only");
        String newShoppingCart = bufferedReader.readLine();
        if (newShoppingCart.equals("Shopify")) {
            ShopifyCredentialsHandler sch = new ShopifyCredentialsHandler();
            test = sch.shopifyCredentialsHandler();
        }
        else if (newShoppingCart.equals("Bigcommerce")) {
        BigcommerceCredentialsHandler bch = new BigcommerceCredentialsHandler();
        test = bch.bigcommerceCredentialsHandler()
        }

        else {
            System.out.println("This method works with Shopify. Try to connect a Shopify store.");
            bufferedReader.close();
        }
    }
    return test;
    // Here I need to return test (in case I choose "Shopify") or test2 (in case I choose "Bigcommerce"). How can I do that?
    }
}

Answer 3

正如您已经意识到的那样，您无法访问＆＃34;测试＆＃34;或＆＃34; test2＆＃34;您想要返回的变量是因为它们都在此时超出了范围。

您需要在顶部（在第一个if语句之前）声明一个String变量，其中变量的范围将扩展到整个credentialsCollector（）方法，或者使用多个返回，将每个返回放在与您的相同的范围内＆＃34;测试＆＃34;和＆＃34; test2＆＃34;变量

如果有多个IF语句，如何返回1个字符串

3 个答案: