FileUtil（from logparser）

 import java.io.BufferedReader;
 import java.io.BufferedWriter;
 import java.io.ByteArrayOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;

 import org.apache.log4j.Logger;

 public class FileUtil
 {
     static Logger logger;

     static {
         FileUtil.logger = Logger.getLogger((Class)FileUtil.class);
     }
     public static <T> T readFile(final String filePath, T container, final String encode) {
         try {
             final File file = new File(filePath);
             if (!file.exists()) {
                 FileUtil.logger.info((Object)("file " + filePath + " does not exists."));
                 return container;
             }
             final FileInputStream fis = new FileInputStream(file);
             final InputStreamReader isr = new InputStreamReader(fis, (encode == null) ? "GBK" : encode);
             final BufferedReader br = new BufferedReader(isr);
             if (container instanceof List) {
                 final List list = (List)container;
                 String string = null;
                 while ((string = br.readLine()) != null) {
                     list.add(string);
                 }
             }
             else if (container instanceof String[]) {
                 String string2 = null;
                 final List<String> list2 = new ArrayList<String>();
                 while ((string2 = br.readLine()) != null) {
                     list2.add(string2);
                 }
                 final int count = list2.size();
                 final String[] strings = new String[count];
                 for (int i = 0; i < count; ++i) {
                     strings[i] = list2.get(i);
                 }
                 container = (T)(Object)strings;
             }
             else if (container instanceof Map) {
                 String string2 = null;
                 final Map map = (Map)container;
                 while ((string2 = br.readLine()) != null) {
                     final int a = string2.indexOf("=");
                     if (a != -1) {
                         map.put(string2.substring(0, a), string2.substring(a + 1));
                     }
                 }
             }
             else if (container instanceof byte[]) {
                 container = (T)getInputStreamBytes(fis);
             }
             br.close();
             isr.close();
             fis.close();
         }
         catch (Exception e1) {
             FileUtil.logger.error((Object)"", (Throwable)e1);
         }
         return container;
     }

     public static <T> T readFile(final InputStream is, T container, final String encode) {
         try {
             final InputStreamReader isr = new InputStreamReader(is, (encode == null) ? "GBK" : encode);
             final BufferedReader br = new BufferedReader(isr);
             if (container instanceof List) {
                 final List list = (List)container;
                 String string = null;
                 while ((string = br.readLine()) != null) {
                     list.add(string);
                 }
             }
             else if (container instanceof String[]) {
                 String string2 = null;
                 final List<String> list2 = new ArrayList<String>();
                 while ((string2 = br.readLine()) != null) {
                     list2.add(string2);
                 }
                 final int count = list2.size();
                 final String[] strings = new String[count];
                 for (int i = 0; i < count; ++i) {
                     strings[i] = list2.get(i);
                 }
                 container = (T)(Object)strings;
             }
             else if (container instanceof Map) {
                 String string2 = null;
                 final Map map = (Map)container;
                 while ((string2 = br.readLine()) != null) {
                     final int a = string2.indexOf("=");
                     if (a != -1) {
                         map.put(string2.substring(0, a), string2.substring(a + 1));
                     }
                 }
             }
             else if (container instanceof byte[]) {
                 container = (T)getInputStreamBytes(is);
             }
             br.close();
             isr.close();
             is.close();
         }
         catch (Exception e1) {
             FileUtil.logger.error((Object)"", (Throwable)e1);
         }
         return container;
     }

     public static void writeFile(final String directory, final String filename, final String encode, final Object... objs) {
         try {
             if (objs != null && objs.length > 0) {
                 final File file = new File(directory);
                 if (!file.exists()) {
                     file.mkdirs();
                 }
                 final FileOutputStream fos = new FileOutputStream(String.valueOf(directory) + "/" + filename);
                 final OutputStreamWriter osw = new OutputStreamWriter(fos, (encode == null) ? "GBK" : encode);
                 final BufferedWriter bw = new BufferedWriter(osw);
                 if (objs.length > 1) {
                     for (int len = objs.length, i = 0; i < len; ++i) {
                         final Object object = objs[i];
                         bw.write((object == null) ? "" : object.toString());
                         if (i != len - 1) {
                             bw.newLine();
                         }
                     }
                 }
                 else if (objs[0] instanceof List) {
                     final List list = (List)objs[0];
                     final Iterator iterator = list.iterator();
                     Object object = null;
                     while (true) {
                         if (iterator.hasNext()) {
                             object = iterator.next();
                             bw.write((object == null) ? "" : object.toString());
                         }
                         if (!iterator.hasNext()) {
                             break;
                         }
                         bw.newLine();
                     }
                 }
                 else if (objs[0] instanceof String[]) {
                     final String[] objects = (String[])objs[0];
                     for (int len2 = objects.length, j = 0; j < len2; ++j) {
                         final String object2 = objects[j];
                         bw.write((object2 == null) ? "" : object2);
                         if (j != len2 - 1) {
                             bw.newLine();
                         }
                     }
                 }
                 else if (objs[0] instanceof Map) {
                     final Map map = (Map)objs[0];
                     final int size = map.size();
                     int count = 0;
                     for (final Object key : map.keySet()) {
                         final Object value = map.get(key);
                         bw.write(String.valueOf((key == null) ? "" : key.toString()) + "=" + ((value == null) ? "" : value.toString()));
                         if (++count != size) {
                             bw.newLine();
                         }
                     }
                 }
                 else if (objs[0] instanceof byte[]) {
                     final byte[] bs = (byte[])objs[0];
                     fos.write(bs);
                 }
                 else {
                     bw.write(objs[0].toString());
                 }
                 bw.close();
                 osw.close();
                 fos.close();
             }
         }
         catch (Exception e) {
             FileUtil.logger.error((Object)"", (Throwable)e);
         }
     }

     public static <T> T readFileSafely(final String filePath, final T container) {
         final String encode = getEncoding(filePath);
         return readFile(filePath, container, encode);
     }

     public static void repOldStr(final File file, final String oldStr, final String newStr) {
         final String encode = getEncoding(file.getPath());
         final List<String> list = readFile(file.getPath(), new ArrayList<String>(), encode);
         final List<String> list2 = new ArrayList<String>();
         for (String str : list) {
             str = str.replace(oldStr, newStr);
             list2.add(str);
         }
         writeFile(file.getParent(), file.getName(), encode, list2);
     }

     private static byte[] getInputStreamBytes(final InputStream is) throws IOException {
         final ByteArrayOutputStream outStream = new ByteArrayOutputStream();
         final byte[] buffer = new byte[1024];
         int len = 0;
         while ((len = is.read(buffer)) != -1) {
             outStream.write(buffer, 0, len);
         }
         final byte[] data = outStream.toByteArray();
         return data;
     }

     public static boolean appendFile(final String filepath, final String... content) {
         if (content == null || content.length == 0) {
             return true;
         }
         try {
             final FileWriter fw = new FileWriter(filepath, true);
             for (int i = 0; i < content.length; ++i) {
                 final String s = content[i];
                 fw.write(String.valueOf(s) + "\r\n");
             }
             fw.close();
             return true;
         }
         catch (Exception e) {
             FileUtil.logger.error((Object)"", (Throwable)e);
             return false;
         }
     }
     public static String getEncoding(final String filepath) {
         return EncodingDetect.getJavaEncode(filepath);
     }
     public static void main(String[] args) {
         String file = "C:\\Users\\lenovo\\Downloads\\a.log";
         String encode=EncodingDetect.getJavaEncode(file);
         System.out.println(encode);
     }
 }