Question

所以，我正在将这个程序作为练习来学习java，

import java.util.Scanner;
import java.io;
import java.nio;

class wordsInLine {

    public static void main(String args[]) {

    int wordCount;

    //checking for correct syntax
    if (args.length > 1){
        System.out.println("Usage : java wordsInLine [path to text file to scan for words, ommit if you want to be asked for input]");
        System.exit(0);
    }

    //if the user has provided a path to a text file then read the file
    if (args.length == 1) {
        Path file = args[0];
        byte[] fileBytes; 
        fileBytes = Files.readAllBytes(file);

        //convert the text of the file to a big string
        String line = new String(fileBytes, StandardCharsets.UTF_8);

    }else{ // else the user wants to give us his/her own line

         //getting the users's input
         Scanner input = new Scanner(System.in);
         String line = input.nextLine();
    }

    //call the word count function
    wordCount = countWords(line);

    //print result
    System.out.println(wordCount + " words found in the input line");
}


public static int countWords(String line){

    //vars for easier understanding and reading
    final boolean IN = true;
    final boolean OUT = false;
    boolean isLetter;
    boolean STATE = false;

    //just counting the words here
    int wordCount = 0;

    //looping through every character of the user's input line
    for (int i = 0, n = line.length(); i < n; i++){
        isLetter = Character.isLetter(line.charAt(i));

        if (isLetter == true){
            STATE = IN;
        }

        if ((STATE == IN) && (isLetter == false)){
                wordCount++;     
                STATE = OUT;
        }

        if (((STATE == IN) && (line.charAt(i) == '\n')) || ((STATE == IN) && (i == (line.length() - 1)))){
            wordCount++;
            STATE = OUT;
        }
    }

    return wordCount;
}

}

我尝试使用javac wordsInLine.java进行编译我明白了 wordsInLine.java:2: error: cannot find symbol import java.io; ^ symbol: class io location: package java wordsInLine.java:3: error: cannot find symbol import java.nio; ^ symbol: class nio location: package java wordsInLine.java:17: error: cannot find symbol Path file = args[0]; ^ symbol: class Path location: class wordsInLine wordsInLine.java:19: error: cannot find symbol fileBytes = Files.readAllBytes(file); ^ symbol: variable Files location: class wordsInLine wordsInLine.java:20: error: cannot find symbol String line = new String(fileBytes, StandardCharsets.UTF_8); ^ symbol: variable StandardCharsets location: class wordsInLine 5 errors

我在网上找到的第二和第三个导入语句，如果我省略它们并且我尝试编译我得到

wordsInLine.java:15: error: cannot find symbol
        Path file = args[0];
        ^
symbol:   class Path
location: class wordsInLine
wordsInLine.java:17: error: cannot find symbol
        fileBytes = Files.readAllBytes(file);
                    ^
symbol:   variable Files
location: class wordsInLine
wordsInLine.java:18: error: cannot find symbol
        String line = new String(fileBytes, StandardCharsets.UTF_8);
                                            ^
symbol:   variable StandardCharsets
location: class wordsInLine

我用谷歌搜索了很多人说我可能有一个过时的java和/或javac版本，

java -version

返回

java version "1.8.0_101"
Java(TM) SE Runtime Environment (build 1.8.0_101-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.101-b13, mixed mode)

也

javac -version

返回

javac 1.8.0_101

我刚开始学习java而且我已经打了一堵砖墙，谁能告诉我，我在这里失踪了什么？

编辑：更改第2和第3个导入语句（由@EJP建议）后，我得到：

wordsInLine.java:17: error: cannot find symbol
        Path file = args[0];
        ^
symbol:   class Path
location: class wordsInLine
wordsInLine.java:19: error: cannot find symbol
        fileBytes = Files.readAllBytes(file);
                    ^
symbol:   variable Files
location: class wordsInLine
wordsInLine.java:20: error: cannot find symbol
        String line = new String(fileBytes, StandardCharsets.UTF_8);
                                            ^
symbol:   variable StandardCharsets
location: class wordsInLine
3 errors

Answer 1

import java.io;
import java.nio;

这些陈述都不是合法的Java。你需要

import java.io.*;
import java.nio.*;

或更好仍然使用您的IDE功能为您执行导入。

导入java.nio后，找不到Javac符号错误

1 个答案: