Question

已给出此代码，并被要求解决此代码。需要帮助来理解如何解决此问题。

    class Main {
public static void main(String[] args) {
    // Should print 7
    System.out.println(stringLength("request")); // this line cannot be changed

    // Should print "request must not be empty"
    System.out.println(stringLength("")); // this line cannot be changed

    // Should print "request is required"
    System.out.println(stringLength(null)); // this line cannot be changed
}

public static Integer stringLength(String request) // this line cannot be changed
{}

Answer 1

评论说您“应该”进行打印，但是没有任何内容表明您在打印后不能再打印其他任何东西。什至没有强迫进行打印，否则将是必须。

说实话，阅读诸如此类的有关作业的问题会让我不高兴。

对我来说，整个过程是无用的，丑陋的，并且没有教给将来的现实世界软件设计和编码任何有价值的东西。它所教的一件事是：给定差的规格，做不好的工作来取悦客户。 嗯...这可能是一个很好的学习课程？

由于您没有提供所尝试内容的任何代码，也没有提供任何有关您所理解内容的暗示，因此我可以自由地提出某种解决方案，以执行所需的打印。

因此，这里有3种实现。我试图粗略地做到这一点。也许其他人会发现其他奇怪的方法来做到这一点。

import java.util.HashMap;
import java.util.Map;

public class Main {
    private static final String REQUEST_MUST_NOT_BE_EMPTY = "request must not be empty";
    private static final String REQUEST_IS_REQUIRED = "request is required";
    private static final String REQUEST = "request";
    private static final String EMPTY_STRING = "";
    private static final Map<String, Object> requestMessageMap = new HashMap<String, Object>();
    static {
        // requestMessageMap.put(REQUEST, Integer.valueOf(7));
        // requestMessageMap.put(REQUEST, Integer.valueOf(REQUEST.length()));
        requestMessageMap.put(EMPTY_STRING, REQUEST_MUST_NOT_BE_EMPTY);
        requestMessageMap.put(null, REQUEST_IS_REQUIRED);
    }

    public static void main(String[] args) {
        // Should print 7
        System.out.println(stringLength("request")); // this line cannot be changed

        // Should print "request must not be empty"
        System.out.println(stringLength("")); // this line cannot be changed

        // Should print "request is required"
        System.out.println(stringLength(null)); // this line cannot be changed
    }

    public static Integer stringLength(String request) // this line cannot be changed
    {
        return sillyMethod4(request);
    }

    private static Integer sillyMethod1(String request) {
        Integer returnValue = -1;
        if (request == null) {
            // do exactly what specification required
            // (completly pointeless)
            System.err.println(REQUEST_IS_REQUIRED);
        } else if (request.equals(EMPTY_STRING)) {
            // do exactly what specification required
            // (completly pointeless)
            System.err.println(REQUEST_MUST_NOT_BE_EMPTY);
        } else if (request.equals(REQUEST)) {
            // do exactly what specification required
            // (completly pointeless)
            returnValue = 7;
        } else {
            // my best guess about what we should really do
            returnValue = request.length();
        }
        return returnValue;
    }

    private static Integer lessSillyMethod2(String request) {
        Integer returnValue = -1;
        if (request == null) {
            // do exactly what specification required
            // (completly pointeless)
            System.err.println(REQUEST_IS_REQUIRED);
        } else if (request.equals(EMPTY_STRING)) {
            // do exactly what specification required
            // (completly pointeless)
            System.err.println(REQUEST_MUST_NOT_BE_EMPTY);
        } else {
            // my best guess about what we should really do
            returnValue = request.length();
        }
        return returnValue;
    }

    private static Integer sillyMethod3(String request) {
        Integer returnValue = -1;
        if (request == null) {
            // do exactly what specification required
            // (completly pointeless)
            System.err.println("request is required: ");
        } else {
            switch (request) {
            case EMPTY_STRING:
                // do exactly what specification required
                // (completly pointeless)
                System.err.println("request must not be empty: ");
                break;
            case REQUEST:
                // do exactly what specification required
                // (completly pointeless)
                returnValue = 7; //
                break;
            default:
                // my best guess about what we should really do
                returnValue = request.length();
                break;
            }
        }
        return returnValue;
    }

    private static Integer sillyMethod4(String request) {
        Integer returnValue = -1;
        if (requestMessageMap.containsKey(request)) {
            System.err.println(requestMessageMap.get(request));
        } else {
            returnValue = request.length();
        }
        return returnValue;
    }
}

输出：

7
request must not be empty
request is required
-1
-1

Answer 2

stringLengt（）方法在将字符串“ request”传递给它时应返回“ 7”，在传递空字符串时应返回不同的值，而在传递null时应返回另一个不同的值。也许您应该看看控制结构，尤其是选择项。另外，您的stringLength方法还需要返回String类型的值。

如何解决下面的编码练习

2 个答案: