如何在java中引用外部文件中的关键字

Question

我还在学习java，所以请耐心等待。我有一个程序，如果你键入一个关键词，它将运行一个方法和东西。我正在尝试做的是创建一个可以随时学习的过程，IE是一个外部命令列表，当它输入时它将像原始关键字一样运行。

这可能没什么意义，所以这里是我想要发生的一个例子：

程序启动，我键入关键字1（为了参数的缘故，说删除），它运行方法。 现在我想输入一个像'删除'这样的关键字，它应该和'删除'一样。由于代码中不存在“删除”，因此我输入“新命令：删除运行删除”或类似内容。在外部文件中，它会创建一行或类似“删除=删除”的内容。现在，当我输入Remove it检查列表文件时，看到remove与delete相同。

对不起，如果这没有多大意义。

就像我说的那样，我仍然处于java的学习过程中，所以对解释的任何帮助都会很棒！

Answer 1

修改 我很确定这几乎就是你想要的东西，我很喜欢它，因为我上次对自己的错误感到很难过。这个甚至会写出用户提供的新命令。我错过了什么？

import java.io.*;
import java.util.ArrayList;

public class test {

  public static void main (String[] args) {
    test t = new test();
    t.test();
  }

  /** A test method for our code **/
  public void test(){
    String[] command = new String[2];

      BufferedReader commands = null;

      //initialize list of commands
      ArrayList<String[]> commandList = new ArrayList<String[]>();

      //Get a list of Commands from a file
      this.getCommands( commandList );

      //get the next command
      BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
      System.out.print("Next Thing?\n");
      this.getCommand( br, command, commandList );
      if ( command[1] == null ){
        System.out.print("New command?\n");
        commandList.add( this.makeCommand( br, command ) );
      }
      else{
        //Not sure what you want to do here, this is if the method IS found
        System.out.println( "We found: "+command[1]);
      }

      this.save(commandList);  
  }

  /**Returns the old list of commands**/
  public void getCommands( ArrayList<String[]> commandList ){
    BufferedReader commands;
    try{
      String sCurrentLine;

      commands = new BufferedReader(new FileReader("testing.txt"));

      while ((sCurrentLine = commands.readLine()) != null) {
        commandList.add( sCurrentLine.split(":") );
      }

    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  /**
  Asks the user for a command and checks it against known commands. It's not a 
  very efficient algorithm, but effective. 
  **/
  public void getCommand( BufferedReader br, String[] command, 
                          ArrayList<String[]> commandList ){

    try {
      command[0] = br.readLine();
      for ( String[] com : commandList ){
        if (com[0].equals( command[0] )){
          command[1] = com[1];
        }
      }
    } 
    catch (IOException ioe) 
      {
       System.out.println("IO error trying to read your commnad!");
      }
  }

  /** Makes a new command, to be used when one isn't known **/
  public String[] makeCommand( BufferedReader br, String[] command ){
    try{
      command[1] = br.readLine();
    }
    catch( IOException ioe)
      {
        System.out.println("Oh no!!!");
      }
      return command;
  }

  /** Saves your stuff **/
  public void save( ArrayList<String[]> commandList){
    try{
      PrintWriter writer = new PrintWriter( "testing.txt","UTF-8" );
      for ( String[] com : commandList ){
        writer.println( com[0]+":"+com[1] );
      }
      writer.close();
    }
    catch( Exception ioe ){
      System.out.println("You're in trouble");
    }
  }


}

Answer 2

java.util.Properties看起来像你需要的。假设您有一个包含单行的文件，将“删除”映射到“删除”，如下所示：

remove = delete

您将使用以下代码创建一个Properties实例并将该文件读入其内部Hashtable，然后重新存储它：

import java.util.*;
import java.io.*;

public class Example
{
    public static void main(String[] args)
    {
        Properties mappings = new Properties();
        BufferedInputStream inStream = new BufferedInputStream(new FileInputStream("path/to/mappings.txt"));
        mappings.load(stream);
        stream.close();
        System.out.println("mappings.getProperty(\"remove\") should return \"delete\":" + mappings.getProperty("remove");
        System.out.println("Mapping \"quit\" to \"exit\"...");
        mappings.setProperty("quit", "exit");
        System.out.println("Saving new mappings...");
        BufferedOutputStream outStream = new BufferedOutputStream(new FileOutputStream("path/to/mappings.txt");
        mappings.store(outStream, "Command aliases for <program name>");
        outStream.close();
    }
}