运行结果

image.png

源码

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;

public class WalkFiles {
    // 以java、jsp为后缀的文件
    static final String FILE_EXTENSION1 = "JAVA";
    static final String FILE_EXTENSION2 = "JSP";

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("输入文件夹路径: ");
        traverseFolder(in.nextLine());
    }

    public static void traverseFolder(String parentFolderPath) {
        File parentFolder = new File(parentFolderPath);
        File[] childrenFiles = null;
        if (parentFolder.isFile()) {
            if (isTextFile(parentFolder)) {
                try {
                    System.out.println(
                            "文件路径: " + parentFolder.getAbsolutePath());
                    printFile(parentFolder);
                    System.out.println("");
                } catch (IOException ioe) {
                    System.exit(1);
                }
            } else {
                // System.out.println("This directory doesn't contain any
                // files!!");
                return;
            }
        } else {
            childrenFiles = parentFolder.listFiles();
            if (childrenFiles.length == 0) {

                return;
            }
            if (!containsDirectory(childrenFiles)) {
                for (File file : childrenFiles) {
                    if (isTextFile(file)) {
                        try {
                            System.out.println(
                                    "File Location: " + file.getAbsolutePath());
                            printFile(file);
                            System.out.println("");
                        } catch (IOException ioe) {
                            System.exit(1);
                        }
                    }
                }
            } else {
                for (File file : childrenFiles) {
                    traverseFolder(file.getAbsolutePath());
                }
            }
        }
    }

    private static boolean containsDirectory(File[] files) {
        for (File f : files) {
            if (f.isDirectory()) {
                return true;
            }
        }

        return false;
    }

    /**
     * 输出读取的内容到控制台
     * 
     * @param file
     * @throws IOException
     */
    private static void printFile(File file) throws IOException {
        BufferedReader reader = new BufferedReader(new FileReader(file));
        String line = reader.readLine();
        while (line != null) {
//          System.out.println(line);
            line = reader.readLine();
            writeToFile(line);
        }
        System.out.println("完成");
    }

    public static void writeToFile(String content) {
        FileWriter fw = null;
        try {
            // 如果文件存在，则追加内容；如果文件不存在，则创建文件
            File f = new File("E:\\test.txt");
            fw = new FileWriter(f, true);
        } catch (IOException e) {
            e.printStackTrace();
        }
        PrintWriter pw = new PrintWriter(fw);
        pw.println(content);
        pw.flush();
        try {
            fw.flush();
            pw.close();
            fw.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static boolean isTextFile(File file) {
        String fileName = file.getName();
        int i = fileName.lastIndexOf('.');
        String fileExtension = fileName.substring(i + 1).toUpperCase();
        if (i > 0 && fileExtension.equals(FILE_EXTENSION1)
                || fileExtension.equals(FILE_EXTENSION2)) {
            return true;
        }
        return false;
    }
}