日志的转储和压缩是非常关键的，它不仅可以减少硬盘空间占用，主要还可以在发生故障时根据日志定位出故障原因。下面来看看golang和java的文件转储实现。

go语言：

用到了filepath包下的Walk方法，具体说明可以参看历史文章：

go语言path/filepath包之Walk源码解析

package main

import (
 "fmt"
 "os"
 "io"
 "archive/zip"
 "path/filepath"
 "time"
 "log"
)

func main() {

 logFile := "D:/tmp/successLog/logs/root.log"

 backFile := "D:/tmp/successLog/logs/root_" + time.Now().Format("20060102150405") + ".zip"
 
 err := zipFile(logFile, backFile)
 if err != nil {
   log.Println(fmt.Sprintf("zip file %s to %s error : %v", logFile, backFile, err))
   return
 } else {
   os.Remove(logFile)
 }

 //转储后创建新文件
 //createFile()

 //修改文件权限
 //os.Chmod(backfile, 0400)

 //删除备份文件
 //deleteOldBackfiles(dir)
}


func zipFile(source, target string) error {

 zipFile, err := os.OpenFile(target, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0440)
 if err != nil {
   log.Println(err)
   return err
 }
 defer zipFile.Close()

 archive := zip.NewWriter(zipFile)
 defer archive.Close()

 return filepath.Walk(source, func(path string, info os.FileInfo, err error) error {
   if err != nil {
     return err
   }

   header, err := zip.FileInfoHeader(info)
   if err != nil {
     return err
   }

   if !info.IsDir() {
     header.Method = zip.Deflate
   }
   header.SetModTime(time.Now().UTC())
   header.Name = path
   writer, err := archive.CreateHeader(header)
   if err != nil {
     return err
   }

   if info.IsDir() {
     return nil
   }
   file, err := os.Open(path)

   if err != nil {
     return err
   }
   defer file.Close()

   _, err = io.Copy(writer, file)
   return err
 })
}

java版：

说明见注释。

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;



import java.io.*;

import java.text.DateFormat;

import java.text.SimpleDateFormat;

import java.util.zip.CRC32;

import java.util.zip.CheckedOutputStream;

import java.util.zip.ZipEntry;

import java.util.zip.ZipOutputStream;



/**

* @program: website

* @description: 转储压缩文件

* @author: smallsoup

* @create: 2018-08-12 17:58

**/



public class ZipFile {



private static final Logger LOGGER = LoggerFactory.getLogger(ZipFile.class);



/**

* 格式化文件名格式

*/

private static final String AUDIT_LOG_FORMAT = "yyyyMMddHHmmssSSS";



/**

* 压缩后文件后缀

*/

private static final String AUDIT_FILE_ZIP_SUFFIX = ".zip";



/**

* 压缩前文件后缀

*/

private static final String AUDIT_FILE_EXT = ".log";



private static final int ZIP_BUFFER = 4096;



/**

* 控制压缩后的文件解压后是否带base路径

*/

private static final String rootPath = "";





public static void main(String[] args) throws IOException {



System.out.println();



new ZipFile().zipAuditLogFile("D:/tmp/successLog/logs/root.log");

}



/**

* 日志压缩

*

* @param waitZipFile 要压缩文件名

* @throws IOException

*/

private void zipAuditLogFile(String waitZipFile) throws IOException {

File oldFile = new File(waitZipFile);



if (!oldFile.exists()) {

LOGGER.error("zipAuditLogFile name is {} not exist", waitZipFile);

return;

}



//生成zip文件名

DateFormat dataFormat = new SimpleDateFormat(AUDIT_LOG_FORMAT);

String formatTime = dataFormat.format(oldFile.lastModified());



int end = waitZipFile.length() - AUDIT_FILE_EXT.length();

String zipFileName = waitZipFile.subSequence(0, end) + "_" + formatTime + AUDIT_FILE_ZIP_SUFFIX;



File zipFile = new File(zipFileName);



FileOutputStream zipfos = null;

ZipOutputStream zipOs = null;

CheckedOutputStream cos = null;





try {

zipfos = new FileOutputStream(zipFile);

cos = new CheckedOutputStream(zipfos, new CRC32());



zipOs = new ZipOutputStream(cos);



compress(oldFile, zipOs, rootPath);



if (zipFile.exists()) {

// 写完的日志文件权限改为400

try {

//linux上才可以运行,windows上需要装cygwin并且把cygwin的bin目录加到环境变量的path中才可以

Runtime.getRuntime().exec("chmod 400 -R " + zipFile);

//压缩后删除旧文件

boolean isDelete = oldFile.delete();

//创建新文件

if (isDelete) {

oldFile.createNewFile();

}

// boolean isSuccess = PathUtil.setFilePermision(zipFile.toPath(), ARCHIVE_LOGFILE_PERMISION);

// LOGGER.warn("set archive file: {}, permision result is {}", zipFile.getAbsolutePath(), isSuccess);

} catch (IOException e) {

LOGGER.error("set archive file:{} permision catch an error: {}", zipFile, e);

}

}



} finally {



if (null != zipOs) {

zipOs.close();

}



if (null != cos) {

cos.close();

}



if (null != zipfos) {

zipfos.close();

}

}

}



/**

* 压缩文件或目录

*

* @param oldFile 要压缩的文件

* @param zipOut 压缩文件流

* @param baseDir baseDir

* @throws IOException

*/

private void compress(File oldFile, ZipOutputStream zipOut, String baseDir) throws IOException {



if (oldFile.isDirectory()) {



compressDirectory(oldFile, zipOut, baseDir);



} else {

compressFile(oldFile, zipOut, baseDir);

}

}



/**

* 压缩目录

*

* @param dir 要压缩的目录

* @param zipOut 压缩文件流

* @param baseDir baseDir

* @throws IOException

*/

private void compressDirectory(File dir, ZipOutputStream zipOut, String baseDir) throws IOException {



File[] files = dir.listFiles();



for (File file : files) {

compress(file, zipOut, baseDir + dir.getName() + File.separator);

}

}



/**

* 压缩文件

*

* @param oldFile 要压缩的文件

* @param zipOut 压缩文件流

* @param baseDir baseDir

* @throws IOException

*/

private void compressFile(File oldFile, ZipOutputStream zipOut, String baseDir) throws IOException {



if (!oldFile.exists()) {

LOGGER.error("zipAuditLogFile name is {} not exist", oldFile);

return;

}



BufferedInputStream bis = null;



try {



bis = new BufferedInputStream(new FileInputStream(oldFile));



ZipEntry zipEntry = new ZipEntry(baseDir + oldFile.getName());



zipOut.putNextEntry(zipEntry);



int count;



byte data[] = new byte[ZIP_BUFFER];



while ((count = bis.read(data, 0, ZIP_BUFFER)) != -1) {

zipOut.write(data, 0, count);

}



} finally {

if (null != bis) {

bis.close();

}

}



}



}

修改权限也可以利用Java7中NIO.2对元数据文件操作的支持，具体可以查看NIO包的使用，其相关教程见文末说明。

代码如下：

package com.website.common;



import java.io.IOException;

import java.nio.file.FileSystems;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.attribute.PosixFilePermission;

import java.nio.file.attribute.PosixFilePermissions;

import java.util.Set;



/**

* 提供文件路径公共函数 改变权限，判断是否正规文件，判断是否路径在安全路径下等

*

* @program: website

* @description: 路径工具, 修改权限

* @author: smallsoup

* @create: 2018-08-14 07:56

**/



public class PathUtil {



/**

* POSIX表示可移植操作系统接口,并不局限于unix类系统

*/

private static final boolean ISPOSIX = FileSystems.getDefault().supportedFileAttributeViews().contains("posix");



/**

* 数字权限格式,如600

*/

private static final int PERM_LEN_THREE = 3;



/**

* 如765 rwxrw_r_x

*/

private static final int PERM_LEN_NINE = 9;





/**

* 设置文件的权限，尽在posix下有效

*

* @param file 文件

* @param perm 权限 类似 “rw-r-----”, "640"

* @return true 修改成功 false 修改失败

* @throws IOException

*/

public static boolean setFilePermision(Path file, String perm) throws IOException {

if (!ISPOSIX) {

return true;

}

// 750 -> "rwxr-x---"

if (perm.length() == PERM_LEN_THREE) {

perm = trans2StrPerm(perm);

}



if (perm.length() != PERM_LEN_NINE) {

return false;

}



Set<PosixFilePermission> perms = PosixFilePermissions.fromString(perm);

Files.setPosixFilePermissions(file, perms);

return true;

}



/**

* 转换

*

* @param digitPerm 长度为3的数字字符串

* @return

*/

private static String trans2StrPerm(String digitPerm) {

StringBuilder builder = new StringBuilder(9);

// owner

builder.append(toStringPerm(digitPerm.charAt(0)));

// group

builder.append(toStringPerm(digitPerm.charAt(1)));

// other

builder.append(toStringPerm(digitPerm.charAt(2)));

return builder.toString();

}



private static String toStringPerm(char ch) {

switch (ch - '0') {

case 7:

return "rwx";

case 6:

return "rw-";

case 5:

return "r-x";

case 4:

return "r--";

case 3:

return "-wx";

case 2:

return "-w-";

case 1:

return "--x";

case 0:

return "---";

default:

return "";

}

}

}