Question

我试图在用户输入字符串命令时使用反射来启动适当的方法。例如，如果用户输入＆＃34;去＆＃34;在终端中，Player类的go（）方法将由Command类的process（）方法调用。

然而，我无法使我的代码工作，并且我得到NoSuchMethodException错误，我不知道如何修复。问题根源的行是Command类的一半（完整的类在底部复制）：

        try {
            Method method = pClass.getMethod(commandWord);
            method.invoke(player, this);
        }
        catch (NoSuchMethodException err1) {
            System.out.println("No such method");
        }

有人可以指导我吗？我提前谢谢你。

LC

命令类：

import java.util.ArrayList;
import java.lang.reflect.*;

public class Command
{

    private String commandWord;
    private String secondWord;

    public Command(String firstWord, String secondWord)
    {
        commandWord = firstWord;
        this.secondWord = secondWord;
    }

    public boolean process(Player player) 
    {
        ArrayList<String> validCommands = new ArrayList<String>();
        String methodName;
        int index;

        Class pClass = player.getClass();
        Method[] methods = pClass.getDeclaredMethods();
        for (int i = 0; i < methods.length; i++) {
            if (Modifier.isPublic(methods[i].getModifiers())) {
                validCommands.add(methods[i].getName());
            }
        }

        boolean wantToQuit = false;

        if(commandWord == null) {
            System.out.println("I don't know what you mean...");
            return false;
        }

        if (commandWord.equals("help")) {
            System.out.println("You are lost. You are alone. You wander");
            System.out.println("around at the university.");
            System.out.println();
            System.out.println("Your command words are:");

            for(String command: validCommands) {
                System.out.print(command + "  ");
            }
            System.out.println();
        }
        else if (commandWord.equals("quit")) {
            wantToQuit = quit();
        }

        //THIS IS WHERE I GET THE ERROR
        try {
            Method method = pClass.getMethod(commandWord);
            method.invoke(player, this);
        }
        catch (NoSuchMethodException err1) {
            System.out.println("No such method");
        }
        catch (IllegalAccessException err2) {
            System.out.println("Illegal access");
        }
        catch (InvocationTargetException err3) {
            System.out.println("Illegal access");
        }

        return wantToQuit;
    }

    [...] //some methods omitted
}

玩家类：

public class Player
{
    private String name;
    private Room currentRoom;
    private ArrayList<Item> items;

    Player (String name, Room startingRoom)
    {
        this.name = name;
        items = new ArrayList<Item>();
        this.currentRoom = startingRoom;
        printWelcome();
    }

    public void engage()
    {
        [...]
    }

    public void trade(Command command) 
    {
        [...]       }

    public void goRoom(Command command) 
    {   
        [...]       }

    public void search(Command command) 
    {
        [...]       }

    public void takeItem(Command command) 
    {
        [...]       }

    public void dropItem(Command command) 
    {
        [...]       }

    public void lock(Command command)
    {   
        [...]       }

    public void unlock(Command command)
    {   
        [...]
    }

}

Answer 1

试试这个。

pClass.getMethod(commandWord, Command.class)

在我看来，问题在于你正在寻找没有任何方法的方法参数虽然这些方法似乎都有Command类型的参数。

有关详细信息，请参阅此处：

Class.getMethod JavaDoc

Java getMethod（）导致NoSuchMethodException错误

1 个答案: