文件操作

package com.iam.utils;

import java.io.DataOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.LineNumberReader;
import java.util.LinkedList;
import java.util.Queue;

import com.iam.constants.CommonConsts;
import com.iam.constants.ToolConsts;
import com.iam.exceptions.MonitorException;

public class FileUtils {
    /**
     * @since 2017-06-28
     */
    public static void main(String[] args) throws MonitorException {
        String filePath = FileUtils.class.getResource("/logs/log.txt").getPath();
        System.out.println(filePath);
        Queue<String> lines = readAppointedLines(new File(filePath), 1, 20);
        for (String line : lines) {
            System.out.println(line);
        }
    }

    public static Queue<String> readLinesByFilters(String filter, File localFile) throws MonitorException {
        if (!CommonUtils.isFile(localFile)) {
            return null;
        }
        Queue<String> lines = new LinkedList<String>();
        LineNumberReader lineReader = null;
        FileReader fileReader = null;
        try {
            fileReader = new FileReader(localFile);
            lineReader = new LineNumberReader(fileReader);
            String text = lineReader.readLine();
            String[] filters = filter.split(ToolConsts.DEFAULT_SPLITTER);
            while (null != text) {
                for (String filtor : filters) {
                    if (text.contains(filtor)) {
                        lines.add(text);
                        break;
                    }
                }
                text = lineReader.readLine();
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            throw new MonitorException("FileNotFoundException occured while read file. "+e.getMessage());
        } catch (IOException e) {
            e.printStackTrace();
            throw new MonitorException("IOException occured while read file. "+e.getMessage());
        } finally {
            if (null != lineReader) {
                try {
                    lineReader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

            if (null != fileReader) {
                try {
                    fileReader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return lines;
    }

    public static Queue<String> readAppointedLines(File localFile, int from, int to) throws MonitorException {

        if (CommonConsts.INT_ONE > from) {
            from = CommonConsts.INT_ONE;
        }
        if (CommonConsts.INT_ONE > to) {
            to = CommonConsts.INT_ONE;
        }
        if (from > to) {
            int temp = to;
            to = from;
            from = temp;
        }
        if (!CommonUtils.isFile(localFile)) {
            throw new MonitorException("Parameter File Object is NOT a File instance.");
        }
        return getFileQueue(localFile, from, to);
    }

    private static Queue<String> getFileQueue(File file, int from, int to) throws MonitorException {
        Queue<String> queue = new LinkedList<String>();
        if (!CommonUtils.isFile(file)) {
            return null;
        }
        FileReader fileReader = null;
        LineNumberReader lineReader = null;
        try {
            fileReader = new FileReader(file);
            lineReader = new LineNumberReader(fileReader);
            while (lineReader.getLineNumber() < from - 1) {
                lineReader.readLine();
            }
            String text = lineReader.readLine();
            do {
                queue.offer(text);
                from++;
                text = lineReader.readLine();
            } while (from < to && null != text);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            throw new MonitorException("FileNotFoundException occured while read file. " + e.getMessage());
        } catch (IOException e) {
            e.printStackTrace();
            throw new MonitorException("IOException occured while read file. " + e.getMessage());
        }finally {
            if (null != lineReader) {
                try {
                    lineReader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

            if (null != fileReader) {
                try {
                    fileReader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return queue;
    }

    public static void write2File(String filePath, String content) throws Exception {
        if (CommonUtils.isNotEmpty(filePath) && CommonUtils.isNotEmpty(content)) {
            File file = new File(filePath);
            if (CommonUtils.isFile(file)
                    || (CommonUtils.isNotDirectory(file) && CommonUtils.isDirectory(file.getParentFile()))) {
                DataOutputStream output = new DataOutputStream(new FileOutputStream(file, true));
                output.write(content.getBytes());
                output.write("\r\n".getBytes());
                output.close();
            }

        }
    }

    public static void deleteAllFiles(String Path) throws Exception {
        if (CommonUtils.isNotEmpty(Path)) {
            File file = new File(Path);
            if (file.isDirectory()) {
                File[] files = file.listFiles();
                for (int i = 0; i < files.length; i++) {
                    if (files[i].isFile())
                        files[i].delete();
                }
            }
        }

    }

}