Java：如果一行包含特定单词，则将其打印一次

Question

I want to take in a text file (given by args[0]) and line by line, check for words given by all the arguments after args[0] and print each line with an asterisk if it contains said words.

I'm pretty sure the code I have at the moment is good enough to check for one word, but I'm unsure how to check for if a line contains multiple words(given by the args) and only to print the line once if it does.

I supposed that a for loop might work, except it would print a line multiple times if it happened to contain multiple words.

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

public class WordFinder
{
    public static void main(String args[])
    {
        File file = new File(args[0]);
        Scanner in = null;
        try
        {
            in = new Scanner(file);
            while(in.hasNext())
            {
                String line = in.nextLine();
                if (line.contains(args[1]))
                {
                    System.out.println("* " + line);
                }
                else
                {
                    System.out.println("  " + line);
                }
            }
        }
        catch (FileNotFoundException e)
        {
            System.out.println("Cannot find " + args[0])
            return;
        }
    }
}

Answer 1

Either you want to check for all (and)

            boolean foundAll = true;
            for (int i = 1; i < args.length && foundAll; ++i) {
                foundAll = foundAll && line.contains(args[i]);
            }
            if (foundAll)
            {
                System.out.println("* " + line);
            }
            else
            {
                System.out.println("  " + line);
            }

Or at least one match (or)

            boolean foundAny = false;
            for (int i = 1; i < args.length; ++i) {
                foundAny = line.contains(args[i]);
                if (foundAny) break;
            }
            if (foundAny)
            {
                System.out.println("* " + line);
            }
            else
            {
                System.out.println("  " + line);
            }

Answer 2

Below is the code which works for all words found.

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class WordFinder {
    private static final String DEFAULT_LINE_INDICATOR = "  ";
    private static final String ALL_WORDS_FOUND_INDICATOR = "* ";

    public static void main(String args[]) {
        File file = new File(args[0]);
        Scanner in = null;
        try {
            in = new Scanner(file);
            while (in.hasNext()) {
                boolean allWordsFound = true;
                String line = in.nextLine();
                for (int index = 1; index < args.length; index++) {
                    allWordsFound = line.contains(args[index]);
                    if (!allWordsFound) {
                        break;
                    }
                }
                String modifiedLine = allWordsFound ? ALL_WORDS_FOUND_INDICATOR + line : DEFAULT_LINE_INDICATOR + line;
                System.out.println(modifiedLine);
            }
        } catch (FileNotFoundException e) {
            System.out.println("Cannot find " + args[0]);
        }
    }
}

If you want any word, you can use the following code

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class WordFinder {
    private static final String DEFAULT_LINE_INDICATOR = "  ";
    private static final String WORD_FOUND_INDICATOR = "* ";

    public static void main(String args[]) {
        File file = new File(args[0]);
        Scanner in = null;
        try {
            in = new Scanner(file);
            while (in.hasNext()) {
                boolean atLeastOneWordFound = false;
                String line = in.nextLine();
                for (int index = 1; index < args.length; index++) {
                    atLeastOneWordFound = line.contains(args[index]);
                    if (atLeastOneWordFound) {
                        break;
                    }
                }
                String modifiedLine = atLeastOneWordFound ? WORD_FOUND_INDICATOR + line : DEFAULT_LINE_INDICATOR + line;
                System.out.println(modifiedLine);
            }
        } catch (FileNotFoundException e) {
            System.out.println("Cannot find " + args[0]);
        }
    }
}

Answer 3

将args放入集合中，并检查文本中的每个单词，直到找到匹配项或eol。