java文件工具类

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.LineIterator;

/**
 * 文件工具类
 * 2017-05-12
 */
public class FileUtil {

    public static void createDir(String destDirName) {
        File dir = new File(destDirName);
        if (!dir.exists()) {// 判断目录是否存在
            dir.mkdir();
            //dir.mkdirs();  //多层目录需要调用mkdirs
        }
    }

     public static File writeToFile(String content, String filePath) throws IOException {
         FileWriter fw = null;
         BufferedWriter bw = null;
         File file = null;
         try {
             file = new File(filePath);
             if (!file.exists()) {
                 file.createNewFile();
             }
             fw = new FileWriter(file.getAbsoluteFile());
             bw = new BufferedWriter(fw);
             bw.write(content);
             bw.flush();// 清空缓冲区
          } catch (IOException e) {
              e.printStackTrace();
          } finally {
              if(bw != null) {
                  bw.close();
              }
              if (fw != null) {
                  fw.close();
              }
          }
         return file;
    }

    public static List<String[]> readTxtFile(File file) {
        LineIterator lineIterator = null;
        List<String[]> list = null;
        try {
            lineIterator = FileUtils.lineIterator(file, "UTF-8");
            list = new ArrayList<String[]>();
            int lineNum = 0;
            while (lineIterator.hasNext()) {
                String line = lineIterator.nextLine();
                // 行数据转换成数组
                String[] custArray = line.split("\\|");
                list.add(custArray);
                lineNum++;
                if (lineNum % 1000 ==0) {
                    Thread.sleep(10);
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            if (lineIterator != null) {
                LineIterator.closeQuietly(lineIterator);
            }
        }
        return list;
    }

    /**
     * 统计文件行数
     * @param file
     * @return
     * @throws IOException
     */
    public static int getTextLines(File file) throws IOException {
       FileReader fr = new FileReader(file);   //这里定义一个字符流的输入流的节点流，用于读取文件（一个字符一个字符的读取）
       BufferedReader br = new BufferedReader(fr);  // 在定义好的流基础上套接一个处理流，用于更加效率的读取文件（一行一行的读取）
       int x = 0;   // 用于统计行数，从0开始
       while(br.readLine() != null) { //  readLine()方法是按行读的，返回值是这行的内容
           x++;   // 每读一行，则变量x累加1
       }
       return x;  //返回总的行数
    }

    public static Map<String, Object> readBaofuTxtFile(File file) {
        LineIterator lineIterator = null;
        List[] list = null;
        int startNum = 0;
        Map<String, Object> map = new HashMap<String, Object>();
        try {
            lineIterator = FileUtils.lineIterator(file, "UTF-8");
            list = new List[getTextLines(file)];
            int lineNum = 0;
            while (lineIterator.hasNext()) {
                String line = lineIterator.nextLine();
                // 行数据转换成数组
                String[] custArray = line.split("\\|");
                List<Object> rowData = new ArrayList<Object>();
                for (int i = 0; i < custArray.length; i++) {
                    rowData.add(custArray[i]);
                }
                if ("商户号".equals(custArray[0])) {
                    startNum = lineNum + 1;
                }
                list[lineNum]=rowData;
                lineNum++;
                if (lineNum % 500 ==0) {
                    Thread.sleep(10);
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            if (lineIterator != null) {
                LineIterator.closeQuietly(lineIterator);
            }
        }
        map.put("data", list);
        map.put("startLineNum", startNum);
        return map;
    }

    public static void main(String[] args) throws IOException {
        /*String content = "This is the content to write into file";
        String filePath = "c:/test/filename.txt";
        writeToFile(content, filePath);*/
        File file = new File("c:/test/fi_20170515132029.txt");
        /*List list  = readTxtFile(file);
        if (list != null) {
            for (int i = 0; i < list.size(); i++) {
                String[] s = (String[]) list.get(i);
                for (int j = 0; j < s.length; j++) {
                    System.out.println(s[j]);
                }
            }
        }*/
        /*Map<String, Object> map = readBaofuTxtFile(file);
        List[] list =  (List[]) map.get("data");
        for (int i = 0; i < list.length; i++) {
            System.out.println(list[i]);
        }*/
    }
}