HELP!What's wrong with my GZIP program?

Question

Here's part of the source code:
static void Compress(String strfilename)     
     int iTemp;
     try
          BufferedReader brIn=new BufferedReader(new FileReader(strfilename));
          BufferedOutputStream bosOut=new BufferedOutputStream(new GZIPOutputStream(new FileOutputStream(strfilename+".gz")));
          while(true)
               iTemp=brIn.read();
               if(iTemp==-1) break;
               bosOut.write(iTemp);                         }
          brIn.close();
          bosOut.close();
     catch(Exception e)
          System.out.println("Error: "+e);
If I use it to compress a small file(20k),the compression is successful,and I can also see it using WINRAR;but once I decompress
this GZIP file,all the English words are correct,while other unicodes
such as Chinese become unrecognizable;
If I use it to compress a "large" file(3M) such as abc.chm,the size of the compressed file is about 2M(INCREDIBLE! WINRAR can only decrease
the size of this file by 30k);But..the size of decompressed file is
still about 2M,and windows cannot read it (Invalid page error).
I wonder what's wrong with my program? Even if I use "javac -encoding
gb2312 ..." to compile my program,the result is also the same.
HOW SHOULD I DO??

Answer 1

Hi, jchc,
Let me help you a little bit, here. hwalkup is correct that for data compression you should use input and output stream instead of readers and writers. I don't think that mixing a reader with an output stream would work anyway as streams read and write bytes (8-bit data), while readers and writers read and write characters (16-bit data). hwalkup is also correct to suggest that you should use a buffer (a byte[]) to improve the performance of your streaming processes.
Here is code for methods to compress and decompress one file into another. Note: the decompress() method will throw an IOException if the file to decompress (inFile) is not actually compressed in the first place.
    public static void compress(File inFile, File outFile)
            throws FileNotFoundException, IOException {
        InputStream in = null;
        OutputStream out = null;
        try {
            in = new BufferedInputStream(new FileInputStream(inFile));
            GZIPOutputStream gzipOut = new GZIPOutputStream(
                                       new FileOutputStream(outFile));
            out = new BufferedOutputStream(gzipOut);
            byte[] buffer = new byte[512];
            for (int i = 0; (i = in.read(buffer)) > -1; ) {
                out.write(buffer, 0, i);
            out.flush();
            gzipOut.finish(); // absolutely necessary
        } finally {
            // always close your output streams before your input streams
            if (out != null) {
                try {
                    out.close();
                } catch (IOException e) {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
    public static void decompress(File inFile, File outFile)
            throws FileNotFoundException, IOException {
        InputStream in = null;
        OutputStream out = null;
        try {
            GZIPInputStream gzipIn = new GZIPInputStream(
                                     new FileInputStream(inFile));
            in = new BufferedInputStream(gzipIn);
            out = new BufferedOutputStream(new FileOutputStream(outFile));
            byte[] buffer = new byte[512];
            for (int i = 0; (i = in.read(buffer)) > -1; ) {
                out.write(buffer, 0, i);
            out.flush();
        } finally {
            // always close your output streams before your input streams
            if (out != null) {
                try {
                    out.close();
                } catch (IOException e) {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
    }Shaun