Java 1.4.2 - 读取文件

Question

我正在尝试读取一个简单的文件，然后读取一个用户应该选择的文件。但我不断收到以下错误:

Readzilla.java:37: cannot find symbol

symbol : method FileReader(java.lang.String)

location: class java.io.BufferedReader

line = read.FileReader(newDoc);

这是代码。

import java.io.*;

    public class Readzilla
    {
        public static void main(String[] args) throws IOException
        {
            String line;
            BufferedReader read;
            // BufferedReader "read" reads the file
            BufferedReader in;
            // BufferedReader "in" reads the input sent by the user  
            String loop;
            // "loop" decides whether another document should be read

            in = new BufferedReader(new InputStreamReader(System.in));
            read = new BufferedReader(new FileReader("message.txt"));
            line = read.readLine();

            while(line != null)
            {
                System.out.println(line);
                line = read.readLine();
            }

            // read another document
            System.out.println("Would you like to read another document? (Y/N)");
            loop = in.readLine();
            loop = loop.toUpperCase();

            if (loop == "Y")
            {
                do
                {
                    System.out.println("What file (.txt) would you like to read?");
                    String newDoc = in.readLine();
                    // newDoc reads a text file of the user's choosing
                    line = read.FileReader(newDoc);
                    //  ^ This line constantly gives errors
                    System.out.println("Reading...");
                    line = read.readLine();

                    while(line != null)
                    {
                        System.out.println(line);
                        line = read.readLine();
                    }

                    // read another document
                    System.out.println("Would you like to read another document? (Y/N)");
                    loop = in.readLine();
                }
                while (loop == "Y");    
            }
            else
            {
                System.out.println("Closing Program...");
            }
        }
    }

Answer 1

你的问题是这一行:

line = read.FileReader(newDoc);

没有名为 FileReader 的方法上课BufferedReader ，这就是编译器解释该行的方式。 FileReader 本身就是一个类，看起来您正在尝试打开一个新文件进行读取。因此，你会想说这样的话:

BufferedReader doc = new BufferedReader(new FileReader(newDoc));

之后，您想要替换

line = read.readLine();

与

line = doc.readLine()

因为这就是您从 BufferedReader 文档引用的文档中读取内容的方式。

此外，您在这里遇到了问题(我看到两次):

loop == "Y"

在 Java 中，== 仅是引用相等。你绝对希望这里的值(value)平等，所以说:

"Y".equals(loop);

这是一个常见的错误；在我看来，== 仅作为引用相等是一个糟糕的设计决策。