从弹簧壳中选择少量选项 [英] select from a small amount of options in spring shell

问题描述

我目前正在尝试使用Spring Shell制作一个cli应用程序.

I am currently trying to make an cli app with Spring Shell.

我希望用户能够快速选择2-3个选项之一.我当前的代码在eclipse中运行良好，但是当我在Powershell中启动它时，我必须多次按Enter键(至少3次)才能选择该选项.按下Enter键一次之后，什么也没发生.

I want the user to able to fast pick one of 2-3 options. My current code works fine in eclipse but when I start it in Powershell, i have to hit enter multiple times (at least 3 times) in order to select the option. After pressing enter once, nothing happens.

我当前的方法:

@ShellMethod(key = { "setService", "select" }, value = "Choose a Speech to Text Service")

public void setService() {
    boolean success = false;
    do {
        this.console.write("Please select a speech recognition service. Type in the number and press enter:");
        this.console.write("1. Google Speech API");
        this.console.write("2. Bing Speech API");

        // Get Input
        Scanner s = new Scanner(System.in);
        String input = s.nextLine();

        // Select Service
        switch (input) {
        case "1":
            /*
             * do something...
             */
            console.write("Google Speech API selected");
            success = true;
            break;
        case "2":
            /*
             * do something...
             */
            console.write("Bing Speech API selected");
            success = true;
            break;
        default:
            this.console.error("Input not valid. Please type a number and press Enter to select a Service");
            break;
        }
    } while (!success);
}

我该如何解决Powershell的问题，还是有一种更优雅的方法来执行此输入?

How can i fix the issue with powershell or is there a more elegant way to perform this input?

推荐答案

Spring Shell 2基于 JLine 3 .对于少量选项"，我建议使用选项卡补全等功能.

Spring Shell 2 is based on JLine 3. For just a "small amount of options" I would recommend to use a feature like tab completion.

(它可以在Powershell上运行，但是在Eclipse-Console中我从未获得任何制表符完成支持).

这很容易:

import java.util.List;
import org.jline.reader.LineReader;
import org.jline.reader.LineReaderBuilder;
import org.jline.reader.impl.completer.StringsCompleter;
import org.jline.terminal.Terminal;
import org.springframework.context.annotation.Lazy;
import org.springframework.shell.standard.ShellComponent;
import org.springframework.shell.standard.ShellMethod;

@ShellComponent
public class CompleterInteractionCommand {

    private final List<String> OPTIONS = List.of("create", "update", "delete");
    private final Terminal terminal;

    public CompleterInteractionCommand(@Lazy final Terminal terminal) {
        this.terminal = terminal;
    }

    @ShellMethod
    public String completeSelect() {
        LineReader lineReader = LineReaderBuilder.builder()
                .terminal(this.terminal)
                .completer(new StringsCompleter(this.OPTIONS))
                .build();
        /* Important: This allows completion on an empty buffer, rather than inserting a tab! */
        lineReader.unsetOpt(LineReader.Option.INSERT_TAB);

        String desription = "select on of this options: " + OPTIONS + "\n"
                          + " use TAB (twice) to select them\n";        
        String input = lineReader.readLine(desription + "input: ").trim();
        return "you selected \"" + input + "\"";
    }
}

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