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) + "
");
            }
            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);  
    }  
}