Question

import java.io.*;
import java.util.Scanner;
import java.util.StringTokenizer;

public class Filereader {
    public static void main(String[] args) throws IOException {

File fil = new File("trans1.txt");
FileReader inputFil = new FileReader(fil);
BufferedReader in = new BufferedReader(inputFil);

//Create scanner to read contents of a file
Scanner scanner = new Scanner(new File("trans1.txt"));

//Create an array to store contents of a file after reading them
String [] tall = new String [100];

int i = 0;

while(scanner.hasNext()){
//Create StringTokenizer object
   StringTokenizer st = new StringTokenizer(scanner.next(),"< , { } >", true);
   tall[i] = scanner.next();
   System.out.println(tall[i]);
   i++;
  }
    in.close();
  }
 }

我想使用上面的代码将文件内容读入数组，并将存储在数组中的值打印到屏幕。每次我运行代码我没有得到所需的输出，有人可以帮助。我的文件内容如下;

5 
<0,{p1}>
<0,{p1}>  -1-> <1>
<1,{p1}>  -2-> <2><3>
<2,{p0}>  -1-> <0>
<3,{p1}>  -1-> <4>
<4,{p0}>  -1-> <3>

Answer 1

我是这样做的：

package cruft;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
import java.util.StringTokenizer;

public class FileTokenizer
{
    private static final String DEFAULT_DELIMITERS = "< , { } >";
    private static final String DEFAULT_TEST_FILE = "data/trans1.txt";

    public static void main(String[] args)
    {
        try
        {
            String fileName = ((args.length > 0) ? args[0] : DEFAULT_TEST_FILE);
            FileReader fileReader = new FileReader(new File(fileName));
            FileTokenizer fileTokenizer = new FileTokenizer();
            List<String> tokens = fileTokenizer.tokenize(fileReader);
            System.out.println(tokens);
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }

    public List<String> tokenize(Reader reader) throws IOException
    {
        List<String> tokens = new ArrayList<String>();

        BufferedReader br = null;

        try
        {
            br = new BufferedReader(reader);
            Scanner scanner = new Scanner(br);
            while (scanner.hasNext())
            {
                StringTokenizer st = new StringTokenizer(scanner.next(), DEFAULT_DELIMITERS, true);
                while (st.hasMoreElements())
                {
                    tokens.add(st.nextToken());                    
                }
            }
        }
        finally
        {
            close(br);
        }

        return tokens;
    }

    public static void close(Reader r)
    {
        try
        {
            if (r != null)
            {
                r.close();
            }
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }
}

如果我针对你的文件运行它，那么这就是我得到的输出：

C:\JDKs\jdk1.6.0_13\bin\java  cruft.FileTokenizer
[5, <, 0, ,, {, p1, }, >, <, 0, ,, {, p1, }, >, -1-, >, <, 1, >, <, 1, ,, {, p1, }, >, -2-, >, <, 2, >, <, 3, >, <, 2, ,, {, p0, }, >, -1-, >, <, 0, >, <, 3, ,, {, p1, }, >, -1-, >, <, 4, >, <, 4, ,, {, p0, }, >, -1-, >, <, 3, >]

你没有说出你期望的输出。

Answer 2

首先你应该说明你的“期望输出”是什么。其次，在你提供的代码中，你甚至不使用你的标记器，你只是无缘无故地创建它。第三，你在循环中调用scanner.next（）两次，可能是无意中跳过了一半的令牌。第四，为什么同时使用Scanner和StringTokenizer？我以为他们做的几乎是一样的。

使用tokenizer进行文件操作

2 个答案: