需求：找到每个文件下以conf结尾的文件内的server-name对应的值（包括文件夹下的文件夹里以conf结尾的文件），注释掉的不用
#可以举一反三，最主要的是提取文件内有规律的数据。
package com; import java.io.*; /** * Created by PJB on 2020/9/2. */ public class Bianli { public static String filename = ""; public static void main(String[] args) throws Exception { String inPath = "C:\\Users\\PJB\\Desktop\\resource\\conf"; String outPath = "C:\\Users\\PJB\\Desktop\\resource\\result.txt"; File file = new File(inPath); //待读取文件或文件夹，文件后缀，文件内容key，输出文件路径 forFile(file,"conf","server_name",outPath); } public static void forFile(File file,String lastStr,String contains,String outPath) throws Exception { File[] files = file.listFiles(); for (File f:files){ if (f.isDirectory()){ forFile(f,lastStr,contains,outPath); } filename = f.getName(); if (f.isFile()&&(filename.substring(filename.lastIndexOf(".")+1)).equals(lastStr)){ //System.out.println(f.getAbsoluteFile()); InputStreamReader reader = new InputStreamReader(new FileInputStream(f),"UTF-8"); BufferedReader bufferedReader = new BufferedReader(reader); String line = ""; while((line = bufferedReader.readLine())!=null){ if (line.startsWith("#")){ continue; } if (line.contains(contains)){ String string = line.substring(line.indexOf(contains)+contains.length()).trim(); System.out.println(string); writeToTXT(string,outPath); } } } } } public static void writeToTXT(String str,String path) throws Exception{ FileOutputStream o = null; byte[] buff = new byte[]{}; File file = new File(path); if (!file.exists()){ file.createNewFile(); } buff = str.getBytes(); o = new FileOutputStream(file,true); o.write(buff); o.flush(); o.close(); } }有了这个模板之后，想要加入或者是修改功能就容易多了。
例如：
1.不检索后缀或者检索多种后缀
2.检索两种key并且以key：value 形式打印
3.附带文件路径的打印，方便检阅
等等
