适用范围：只适用于在文本文档中查找（如，txt、java、c等等，并不适用与doc、xls等等这些文件），可嵌套文件夹。但是对中文不支持。

例如：文件夹：F:/demo

子文件夹：F:/demo/ert

 查找结果：

最后附上全部代码：

1 package com.stafen.main; 2  3 import java.io.File; 4 import java.io.IOException; 5 import java.util.ArrayList; 6 import java.util.Collection; 7 import java.util.List; 8  9 import org.apache.commons.io.FileUtils;10 import org.apache.commons.io.IOUtils;11 12 public class Test {13 　　/** 要查找的字符串 **/14     private static String strSearch = "QCNEA";15     /** 要查找的目录名称 **/16     private static String strPath = "E:/Project";17     18     @SuppressWarnings("unchecked")19     public static void main(String[] args) {20         21         File searchDir = new File(strPath);22         List
     
       list = new ArrayList
      
       ();23         try {24             Collection
       
         files = FileUtils.listFiles(searchDir, null, true);25             List
        
          lines = null;26             for (File file : files) {27                 try {28                     lines = FileUtils.readLines(file, "UTF-8");29                 } catch (IOException e) {30                     e.printStackTrace();31                 }32                 for (int i = 0; i < lines.size(); i++) {33                     if (lines.get(i).indexOf(strSearch) != -1) {34                         Search s = new Search();35                         s.setFilename(file.getPath());36                         s.setLine(i + 1);37                         s.setContent(lines.get(i));38                         list.add(s);39                     }40                 }41             }42             StringBuffer sb = new StringBuffer();43             if(list.size() == 0) {44                 System.out.println("【没有查到该字符串！】");45                 return ;46             }47             for (Search s : list) {48                 sb.append("文件路径：" + s.getFilename() + "\n行数：" + s.getLine() + " \n所在行内容：" + s.getContent()).append(IOUtils.LINE_SEPARATOR);49                 sb.append("---------------------------------------------------------------------\n");50             }51             System.out.println(sb.toString());52         } catch (Exception e) {53             System.out.println("【没有找到该目录！】");54         }55     }56 57 }
        
       
      
     

 Search.java文件

public class Search {    private String filename;    private int line;    private String content;    public String getFilename() {        return filename;    }    public void setFilename(String filename) {        this.filename = filename;    }    public String getContent() {        return content;    }    public void setContent(String content) {        this.content = content;    }    public void setLine(int line) {        this.line = line;    }    public int getLine() {        return line;    }}