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Finding substring from a string using regex java

I have a String:
String s = "msqlsum81pv 0 0 25 25 25 2 -sn D:\\workdir\\PV 81\\config\\sum81pv.pwf -C 5000";
I want to get the path (in this case D:\\workdir\\PV 81\\config\\sum81pv.pwf) from this string. This path is an argument of a command option -sn or -n, so this path always appears after these options.
The path may or may not contain whitespaces, which needs to be handled.
public class TestClass {
public static void main(String[] args) {
String path;
String s = "msqlsum81pv 0 0 25 25 25 2 -sn D:\\workdir\\PV 81\\config\\sum81pv.pwf -C 5000";
path = s.replaceAll(".*(-sn|-n) \"?([^ ]*)?", "$2");
System.out.println("Path: " + path);
}
}
Current output: Path: D:\workdir\PV 81\config\sum81pv.pwf -C 5000
Expected output: Path: D:\workdir\PV 81\config\sum81pv.pwf
Below Answers working fine for the earlier case.
i need a regex which return `*.pwf` path if the option is `-sn, -n, -s, -s -n, or without -s or -n.`
But if I have below case then what would be the regex to find password file.
String s1 = msqllab91 0 0 1 50 50 60 /mti/root/bin/msqlora -n "tmp/my.pwf" -s
String s2 = msqllab92 0 0 1 50 50 60 /mti/root/bin/msqlora -s -n /mti/root/my.pwf
String s3 = msqllab93 0 0 1 50 50 60 msqlora -s -n "/mti/root/my.pwf" -C 10000
String s4 = msqllab94 0 0 1 50 50 60 msqlora.exe -sn /mti/root/my.pwf
String s5 = msqllab95 0 0 1 50 50 60 msqlora.exe -sn "/mti/root"/my.pwf
String s6 = msqllab96 0 0 1 50 50 60 msqlora.exe -sn"/mti/root"/my.pwf
String s7 = msqllab97 0 0 1 50 50 60 "/mti/root/bin/msqlora" -s -n /mti/root/my.pwf -s
String s8 = msqllab98 0 0 1 50 50 60 /mti/root/bin/msqlora -s
String s9 = msqllab99 0 0 1 50 50 60 /mti/root/bin/msqlora -s -n /mti/root/my.NOTpwf -s -n /mti/root/my.pwf
String s10 = msqllab90 0 0 1 50 50 60 /mti/root/bin/msqlora -sn /mti/root/my.NOTpwf -sn /mti/root/my.pwf
String s11 = msqllab901 0 0 1 50 50 60 /mti/root/bin/msqlora
String s12 = msqllab902 0 0 1 50 50 60 /mti/root/msqlora-n NOTmy.pwf
String s13 = msqllab903 0 0 1 50 50 60 /mti/root/msqlora-n.exe NOTmy.pwf
i need a regex which return *.pwf path if the option is -sn, -n, -s, -s -n, or without -s or -n.
path contains *.pwf file extension only not NOTpwf or any other extension and code should all work except the last two because it is an invalid command.
Note: I already asked this type of question but didn't get anything working as per my requirement. (How to get specific substring with option vale using java)

You can use:
path = s.replaceFirst(".*\\s-s?n\\s*(.+?)(?:\\s-.*|$)", "$1");
//=> D:\workdir\PV 81\config\sum81pv.pwf
Code Demo
RegEx Demo

Try this
String s = "msqlsum81pv 0 0 25 25 25 2 -sn D:\\workdir\\PV 81\\config\\sum81pv.pwf -C 5000";
int l=s.indexOf("-sn");
int l1=s.indexOf("-C");
System.out.println(s.substring(l+4,l1-2));

You can also use : [A-Z]:.*\.\w+
Demo and Explaination

Rather than using complex regexps for replacing, I'd rather suggest a simpler one for matching:
String s = "msqlsum81pv 0 0 25 25 25 2 -sn D:\\workdir\\PV 81\\config\\sum81pv.pwf -C 5000";
Pattern pattern = Pattern.compile("\\s-s?n\\s*(.*?)\\s*-C\\s+\\d+$");
Matcher matcher = pattern.matcher(s);
if (matcher.find()){
System.out.println(matcher.group(1));
}
// => D:\workdir\PV 81\config\sum81pv.pwf
See the IDEONE Demo
If the -C <NUMBER> is optional at the end, wrap with an optional group -> (?:\\s*-C\\s+\\d+)?$.
Pattern details:
\\s - a whitespace
-s?n - a -sn or -n (as s? matches an optional s)
\\s* - 0+ whitespaces
(.*?) - Group 1 matching any 0+ chars other than a newline
\\s* - ibid
-C - a literal -C
\\s+ - 1+ whitespaces
\\d+ - 1 or more digits
$ - end of string.

Different data when printing and writing to file

There is a stream of data which is sent from server. I need to store this byte stream into a file. The problem is the data which I output to console and the one which I store in a file are different. Seems like there is a change in format of data when I stored in a file.
Here is the program:
try
{
System.out.println("My Address is "+serverSocket.getLocalSocketAddress());
Socket server = serverSocket.accept(); // return a new socket
System.out.println("Connected to client "+server.getRemoteSocketAddress());
inputStream = server.getInputStream();
in = new DataInputStream(inputStream);
out = new FileOutputStream("output.txt");
ArrayList<Byte> bytes = new ArrayList<Byte>();
int curi;
byte cur;
byte[] curBytes = null;
int length = 0;
System.out.println("Before while loop");
while((curi = in.read())!=-1 && count!=500)
{
System.out.println(count+" Reading some data");
//out.write(curi);
cur = (byte)curi;
bytes.add(cur);
curBytes = getPrimativeArray(bytes);
String curBytesString = new String(curBytes, "UTF-8");
count++;
}
int i=0;
for(byte b : bytes)
{
System.out.print(b+" ");
curBytes[i] = b;
i++;
}
out.write(curBytes);
server.close();
}
catch(IOException e)
{
e.printStackTrace();
}
What I print using System.out.print(b+" "); and the one I store in curBytes[] are the same thing. But when I compare the console and file output, they are different.
Console output: 0 0 113 -100 -126 -54 0 32 14 1 0 0 1 -58 60 54 0 3 63 -2 85 74 -81 -88 0 9 1 24 85 74 -81 -48 0 13 65 -113 85 74 -81 -88 0 12 125 -126 85 74 -81 -88 0 13 21 97 85 74 -81 -88 0 13 31 19 85 74 -81 -48 0 13 42 24 0 6 0 0 0 0 0 0 0 0 0 0 32 0 7 -100 0 -5 6 -128 0 -56 29 -127 23 112 -1 -1 0 0 64 0 1 -121 28 115 105 112 58 43 49 52 50 50 50 48 57 57 57 49 53 64 111 110 101 46 97 116 116 46 110 101 116 28 115 105 112 58 43 49 52 50 50 50 48 57 57 57 54 53 64 111 110 101 46 97 116 116 46 110 101 116 37 50 57 54 53 45 49 53 48 53 48 54 50 51 50 55 48 50 45 50 48 53 48 54 54 50 55 54 54 64 48 48 55 56 48 48 49 49 16 32 1 5 6 64 0 0 0 32 16 0 0 0 120 0 17 16 32 1 24 -112 16 1 46 2 0 0 0 0 0 0 0 6 1 -113 0 4 0 33 -64 -42 0 91 5 8 0 9 0 -56 0 0 0 15 3 85 74 -81 -88 0 12 -120 -28 8 0 9 0 -56 0 0 0 15 3 85 74 -81 -88 0 12 -44 -39 8 0 4 0 -56 0 0 1 11 3 85 74 -81 -88 0 9 1 24 8 0 5 0 0 0 0 0 0 3 85 74 -81 -88 0 13 31 19 8 0 1 0 -56 0 0 0 6 3 85 74 -81 -48 0 13 42 24 -64 34 4 24 9 89 83 73 80 47 50 46 48 47 84 67 80 32 91 50 48 48 49 58 53 48 54 58 52 48 48 48 58 48 58 50 48 49 48 58 48 58 55 56 58 49 49 93 58 49 51 55 48 59 98 114 97 110 99 104 61 122 57 104 71 52 98 75 50 57 48 45 48 48 55 56 48 48 49 49 45 48 48 48 102 45 52 52 49 57 55 49 52 48 51 3 85 74 -81 -88 0 12 -120 -28 127 83 73 80 47 50 46 48 47 84 67 80 32 91 50 48 48 49 58 53 48 54 58 52 48 48 48 58 48 58 50 48 49 48 58 48 58 55 56 58 49 49 93 58 49 51 55 48 59 114 101 99 101 105 118 101 100 61 50 48 48 49
File Output: ^#^#q<9c><82>Ê^# ^N^A^#^#^AÆ<6^#^C?þUJ¯¨^# ^A^XUJ¯Ð^#^MA<8f>UJ¯¨^#^L}<82>UJ¯¨^#^M^UaUJ¯¨^#^M^_^SUJ¯Ð^#^M*^X^#^F^#^#^#^#^#^#^#^#^#^# ^#^G<9c>^#û^F<80>^#È^]<81>^Wpÿÿ^#^##^#^A<87>^\sip:+14222099915#one.att.net^\sip:+14222099965#one.att.net%2965-150506232702-2050662766#00780011^P ^A^E^F#^#^#^# ^P^#^#^#x^#^Q^P ^A^X<90>^P^A.^B^#^#^#^#^#^#^#^F^A<8f>^#^D^#!ÀÖ^#[^E^H^# ^#È^#^#^#^O^CUJ¯¨^#^L<88>ä^H^# ^#È^#^#^#^O^CUJ¯¨^#^LÔÙ^H^#^D^#È^#^#^A^K^CUJ¯¨^# ^A^X^H^#^E^#^#^#^#^#^#^CUJ¯¨^#^M^_^S^H^#^A^#È^#^#^#^F^CUJ¯Ð^#^M*^XÀ"^D^X YSIP/2.0/TCP [2001:506:4000:0:2010:0:78:11]:1370;branch=z9hG4bK290-00780011-000f-441971403^CUJ¯¨^#^L<88>ä^?SIP/2.0/TCP [2001:506:4000:0:2010:0:78:11]:1370;received=2001
Please let me know at what step I'm making a mistake.

The other answers here tell you to use a PrintWriter or a FileWriter instead of the FileOutputStream but I'm fairly sure that this is not what you want.
Your problem is that you're writing raw bytes to a file and then reading it back as characters and comparing that to byte values represented as characters and then printed with System.out.
Let's take a look at what happens when you print a byte with the value 65 (or 01000001 in binary).
When you use System.out.print you will invoke PrintStream.print(int) with the integer value of 65 which will in turn print the characters 6 and 5 to the terminal.
When you use out.write you will invoke FileOutputStream.write(byte[]) which will write the bits 01000001 to the file.
Later, when you check the contents of the file your tool will try to interpret this byte as a character and it will most likely use the ASCII encoding to do so (even if you're using Unicode as your default encoding this is likely what will happen since Unicode is a superset of ASCII). This results in the character A being printed.
If you want to view the output file in a way similar to what you've printed with System.out.print you can use the following command on linux:
$ hexdump -e '/1 "%i "' <file>
Example:
$ cat /etc/issue
Ubuntu 12.04.5 LTS \n \l
$ hexdump -e '/1 "%i "' /etc/issue
85 98 117 110 116 117 32 49 50 46 48 52 46 53 32 76 84 83 32 92 110 32
92 108 10 *

My first answer was wrong, so I am editing this because I made the assumption that you could write out a string to the FileOutputStream, but I don't think that is the case. FileOutputStream is only used for byte streams, so you've got to stick to that format when writing out to the file.
If you hold the data in a buffer[array], and then write those bytes out to a file that you have created using the output stream, it should work. I found this document that might be helpful.
The main idea is that somewhere in your code, the byte array isn't getting written to the file correctly. Perhaps its just a matter of adding the close() method.
out.close();
server.close();
reading and writing files in java
Here is the section I found useful.
import java.io.*;
public class Test {
public static void main(String [] args) {
// The name of the file to create.
String fileName = "temp.txt";
try {
// Put some bytes in a buffer so we can
// write them. Usually this would be
// image data or something. Or it might
// be unicode text.
String bytes = "Hello theren";
byte[] buffer = bytes.getBytes();
FileOutputStream outputStream =
new FileOutputStream(fileName);
// write() writes as many bytes from the buffer
// as the length of the buffer. You can also
// use
// write(buffer, offset, length)
// if you want to write a specific number of
// bytes, or only part of the buffer.
outputStream.write(buffer);
// Always close files.
outputStream.close();
System.out.println("Wrote " + buffer.length +
" bytes");
}
catch(IOException ex) {
System.out.println(
"Error writing file '"
+ fileName + "'");
// Or we could just do this:
// ex.printStackTrace();
}
}
}

The console (System.out) is a PrintWriter, while the file output is a FileOutputStream.
The basic difference between Stream and Writer: Streams are supposed to manipulate "raw data", like numbers taken directly from binary format, while writers are used to manipulate "human-readable data", transforming all the data you write.
For example, the 6 int is different from the 6 character. When you use a stream, you write directly the int, while with a writer, the data wrriten is transformed into the character.
Then, if you want your file output to be the same as your console output, do not use FileOutputStream, but instead, use FileWriter, and it's method write(String).
How to make this work:
1 - replace out = new FileOutputStream("output.txt"); by out = new FileWriter("output.txt");
2 - replace out.write(curBytes); by:
for (byte b : curBytes) {
out.write(b + " ");
}

I would suggest you use IOUtils.copy and use a BufferedReader
to wrap your InputStream.
The output stream should obviously be FileOutputStream
I hope this helps

java.lang.ClassCastException: com.itextpdf.text.pdf.PdfNull cannot be cast to com.itextpdf.text.pdf.PdfDictionary

Getting below Exception while trying to read byte array using iText PdfReader,
Below is my code, I'm able to open this file in Acrobat reader
PdfReader reader = new PdfReader(bFile);
Exception:
java.lang.ClassCastException: com.itextpdf.text.pdf.PdfNull cannot be cast to com.itextpdf.text.pdf.PdfDictionary
at com.itextpdf.text.pdf.PdfReader$PageRefs.iteratePages(PdfReader.java:3712)
at com.itextpdf.text.pdf.PdfReader$PageRefs.iteratePages(PdfReader.java:3743)
at com.itextpdf.text.pdf.PdfReader$PageRefs.readPages(PdfReader.java:3548)
at com.itextpdf.text.pdf.PdfReader$PageRefs.<init>(PdfReader.java:3518)
at com.itextpdf.text.pdf.PdfReader$PageRefs.<init>(PdfReader.java:3496)
at com.itextpdf.text.pdf.PdfReader.readPages(PdfReader.java:1142)
at com.itextpdf.text.pdf.PdfReader.readPdf(PdfReader.java:659)
at com.itextpdf.text.pdf.PdfReader.<init>(PdfReader.java:176)
at com.itextpdf.text.pdf.PdfReader.<init>(PdfReader.java:244)
at com.itextpdf.text.pdf.PdfReader.<init>(PdfReader.java:234)
Im using iText 5.4.4, I couldn't find much details in googling. It looks PDF has some issues, couldn't get whats the issue. Below is the excerpts from PDF
%PDF-1.5
%âãÏÓ
1 0 obj
<<
/Type /Catalog
/Lang (en-US)
/StructTreeRoot 39 0 R
/MarkInfo <<
/Marked true
>>
/Pages 187 0 R
/AcroForm 350 0 R
/OCProperties 2131 0 R
/Outlines 2531 0 R
/OpenAction <<
/Type /Action
/S /GoTo
/D [ 3 0 R /XYZ 0 792 0 ]
>>
/ViewerPreferences <<
/HideToolbar false
/HideMenubar false
/HideWindowUI false
/FitWindow false
/CenterWindow false
>>
UPDATE: After debugging I found that /Pages 187 0 R is the problem. If I change to /Pages 2 0 R then it works. Could some please help me what does that /Pages refers ?

PNG True color with Alpha decoding

I am writing a PNG decoder and I am encountering some weirdness. Going through the PNG file format, I have managed to decode PNGs with Color Index + tRNS (alpha) and True Color + tRNS (alpha) correctly. I am currently not sure why I cannot decode a PNG with True Color with Alpha type PNG. I have verified that my inflate of IDAT chunk is correct. Here's what the chunks looks like:
Width: 256
Height: 256
Bit Depth: 8
Color Type: 6
Compression: 0
Filter: 0
Interlace: 0
Length: 25
Type: tEXt
Data: 53 6f 66 74 77 61 72 65 00 41 64 6f 62 65 20 49 6d 61 67 65 52 65 61 64 79
CRC: 71c9653c
Length: 20690
Type: IDAT
Data: 78 da ec 7d 09 9c 1c 57 99 df f7 7a a6 e7 3e 5a a3 fb ...
CRC: 21550259
The actual data is too long to be printed here. Here's my logic of decoding this, please correct me if I'm wrong:
Inflate all the bytes given in the IDAT chunk
Un-filter the inflated chunks. In this case, all filters are of type 0 and therefore, we simply discard the filter byte.
Since this is color type 6, a pixel is represented by RGBA channels with 1 byte each. This means we need to interpret 4 bytes at a time. The following code is used:
ByteBuffer image = BufferUtil.getDirectByteBuffer(data.length, ByteOrder.BIG_ENDIAN);
int i = 0;
while(i < data.length){
int color = ( (data[i] & 0xff) << 24) | ( (data[i+1] & 0xff) << 16) | ( (data[i+2] & 0xff) << 8) | (data[i+3] & 0xff);
image.putInt(color);
i += 4;
What's strange is that I get mostly RRGGBBAA = 0x00000000 data resulting in a clear image with little color.

The problem is you are neglecting to observe the filtering for each scanline.
From the image provided the decompressed data looks like
1 ffffffff 0 0 0 ...
2 0 0 0 0 0 0 ...
..
the first value in each line conforms to the filter method used [http://www.w3.org/TR/PNG/#9Filters]
the scanlines post processing will look like
ffffffff ffffffff ffffffff ...
ffffffff ffffffff ffffffff ...
...
here is some example code that handles methods 0, 1 and 2.
private static void processScanLine(byte filterValue, byte[] scanLine, byte[] previousScanLine) {
switch(filterValue){
case 0:break;
case 1:
for (int i =4;i<scanLine.length;i++){
scanLine[i] = (byte)(scanLine[i]+scanLine[i-4]);
}
break;
case 2:
for (int i =0;i<scanLine.length;i++){
scanLine[i] = (byte)(scanLine[i]+previousScanLine[i]);
}
break;
}
}

'Not in gzip format" error when decompressing gzip inputstream in java

My code is attempting to decompress an input stream read from a gzipped file.
Here is the code snippet:
InputStream is = new GZIPInputStream(new ByteArrayInputStream(fcontents.getBytes()));
The file itself is fine:
$cat storefront3.gz | gunzip
180028796
80026920
180028796
180026921
8002790180
800001
1800002
1800007
800008
800009
The data read in prior to the top code snippet via FileInputStream sure looks like gzip stuff (note the original file was storefront3.tsv):
��[�Rstorefront3.tsvu���0k{)�?�/FBģ��Y'��Q�a���s~���}6���d�{2+���O���D�m~�O��
But get the following:
Caused by: java.io.IOException: Not in GZIP format
at java.util.zip.GZIPInputStream.readHeader(GZIPInputStream.java:141)
at java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:56)
at java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:65)
Here is a hex dump of the .gz file
23:40:44/storefronts:72 $od -cx storefront3.gz
0000000 037 213 \b \b 201 [ 347 R \0 003 s t o r e f
8b1f 0808 5b81 52e7 0300 7473 726f 6665
0000020 r o n t 3 . t s v \0 u 212 273 025 200 0
6f72 746e 2e33 7374 0076 8a75 15bb 3080
0000040 \f 003 k { 032 ) 200 ? 373 / F B ģ ** 302 131
030c 7b6b 291a 3f80 2ffb 4246 a3c4 cdc2
0000060 Y ' 261 200 Q 331 a 276 276 350 001 s ~ 222 262 175
2759 80b1 d951 be61 e8be 7301 927e dcb2
0000100 } 6 226 231 367 d 200 { 2 + 211 337 342 020 O 022
367d 9996 64f7 7b80 2b32 df89 10e2 f14f
0000120 022 343 035 246 D 211 m ~ 003 326 O 235 030 236 \0 \0
e312 a61d 8944 7e6d d603 9d4f 9e18 0000
0000140 \0
0000
UPDATE
I also tried to use FileInputStream. Following gives same error
GZIPInputStream strm = new GZIPInputStream(new FileInputStream(tmpFileName));

Since fcontents contains your gzipped data it should be a byte[] and not a String?
I recommend using IOUtils for reading the file into a byte array as reading it into a string will most likely corrupt your data.