Question

我有这段代码，而且我是Java的新手，并且想知道是否可以从hashmap调用void方法。

例如

HashMap<String, String[]> responses = new HashMap<String, String[]>();
String[] temp5 ={ " Assignment 1", "Assignment 2"};
    responses.put("what is the current assignment", Writer());

void函数是

Void Writer(){

File file = new File("data.txt");


try (BufferedWriter wr = new BufferedWriter(newFileWriter(file.getAbsoluteFile(), true))) {



        System.out.println(" enter what you want to teach me");
        Scanner Keyboard = new Scanner(System.in);
        String lines = Keyboard.nextLine();
        // for(String line : lines){
         wr.write(lines);
        wr.write("\n");

        wr.newLine();
        // }
        // }
        wr.close();
    } catch (IOException e) {
        System.out.println(" cannot write to file " + file.toString());
    }

    return null;

}

Answer 1

是的，您可以在HashMap put中调用方法，但该方法必须返回HashMap存储的任何内容。

根据您的情况HashMap<String, String[]>，您的方法必须返回String[]

想象一个方法

public String[] fakeData() {
   String[] result;
   //some logic that initializes result
   return result;
}

所以你可以称之为：

responses.put("Foo", fakeData());

一个完整的例子：

public class Test {

    public String[] fakeData() {
        String[] x = new String[5];
        Random rand = new Random();
        for(int i = 0; i < 5; i++) {
            x[i] = "Data: " + rand.nextInt(50);
        }
        return x;
    }

    public static void main(String[] args) throws Exception {
        Test t = new Test();
        HashMap<String,String[]> responses = new HashMap<>();
        responses.put("Foo", t.fakeData());

        for(Map.Entry<String,String[]> entry : responses.entrySet()) {
            System.out.println("Key: " + entry.getKey());
            System.out.println("Value: ");
            for(String s : entry.getValue()) {
                System.out.println("\t" + s);
            }
        }
    }
}

Answer 2

我正在创建一个写入文件的void函数。所以void函数是

    public static void Writer() {

    File file = new File("data.txt");
    try (BufferedWriter wr = new BufferedWriter(new FileWriter(
            file.getAbsoluteFile(), true))) { // Creates a writer object
                                                // called wr
                                                // file.getabsolutefile
                                                // takes the filename and
                                                // keeps on storing the old
                                                // data

        System.out.println(" enter what you want to teach me");
        Scanner Keyboard = new Scanner(System.in);
        String lines = Keyboard.nextLine();
         wr.write(lines);
        wr.write("\n");

        wr.newLine();

        wr.close();
    } catch (IOException e) {
        System.out.println(" cannot write to file " + file.toString());
    }


}

并且hashmap函数是

HashMap<String, String[]> responses = new HashMap<String, String[]>();
    String[] temp0 = { "What does that suggest to you?", "I see.",
            "I'm not sure I understand you fully.", "Can you elaborate?",
            "That is quite interesting." };
    responses.put("NOTFOUND", temp0);


    String[] temp1 = { "I'm sorry I do not know, but can you help me learn?" };
    responses.put("sure", temp1);

     String[] temp2 = { "I am sorry to hear you are *.",
            "How long have you been *?",
            "Do you believe it is normal to be *?", "Do you enjoy being *?" };
    responses.put("i am", temp2);
    responses.put("i'm", temp2);

    String[] temp3 = { "Tell me more about such feelings.",
            "Do you often feel *?", "Do you enjoy feeling *?",
            "Why do you feel that way?" };
    responses.put("i feel", temp3);

   //String [] temp8 = {Writer()};

    String[] temp4 = {"is that all?"};

    responses.put("now",  temp4);
      responses.put("now",Writer() );

    String[] temp5 ={ " Assignment 1", "Assignment 2"};
    responses.put("what is the current assignment", temp5);

    String[] keywords = { "i think", "i am", "i'm", "i feel","sure","learn","done","now","what is the current assignment" };

因此，目的是为每个找到任何关键字的实例调用Writer方法。在这种情况下，关键字是“now”，并且调用writer函数来写入文件。

我如何从String数组Hashmap调用方法

2 个答案: