I am trying to read file,but it is reading only on my machine,it is not working on another machine.Here is my code..
FileInputStream fstream=new FileInputStream("/path of myfile/User.txt");
DataInputStream in = new DataInputStream(fstream);
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String str;
while ((str = br.readLine()) != null) {
System.out.println(str);
}
Please help me,how to read file on another machine as well,what changes should I make?
I'm just guessing that you already found a way to share the file, either with HTTP, FTP, SMB or NFS, but you've some problems, perhaps some funny characters appearing in the text. If you don't name the encoding that you want to use, the default one for the machine will be used, and if they have different defaults, you'll run into problems.
Choose an encoding when writing and reading, for example for UTF8 universal encoding, your source should be modified as:
BufferedReader br = new BufferedReader(new InputStreamReader(in, "UTF8"));
When you write your file, of course, you've to use the same encoding, for instance:
FileOutputStream fos = new FileOutputStream("/path of myfile/User.txt");
OutputStreamWriter out = new OutputStreamWriter(fos, "UTF-8");
If you want to read a file that resides on another machine, you have to serve that file using some kind of network server, like an http-server or an smb-server.
Related
I'm currently trying to make a program that can take in a file path, such as
File file = new File("D:\\Servers\\TestServer\\server.jar");
and if it is running, retrieve the running process's InputStream to be read. I have been able to accomplish this if I start the process myself (in the program), but what if the given process was already running by the time the program opened?
I've tried things such as the following:
InputStream inputStream = new FileInputStream(file);
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader bis = new BufferedReader(inputStreamReader);
String line;
while ((line = bis.readLine()) != null) {
System.out.println(line);
}
But, this reads the file itself, not it's running process (I think, at least). Anything helps, thanks!
I'm a bit new to programming so please let me know if there's any more information you may need and I can gladly provide it. Thanks :-)
I have a question regarding reading files in java.
Here is the sample code
File path = new File("myfile.txt");
InputStream inputStream = new FileInputStream(file);
BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
file.delete();
String line;
while((line = reader.readLine()) != null) {
System.out.println(line);
}
I create an input stream and try to read it. As they say, its like a pipe, you read values byte by byte.
To speed it up, we can use BufferedReader which can read chunk by chunk.
So, I delete this file before reading.
Now, when i read it, it still reads complete file, even though file is not there.
If inputStream is a pipe, why is it not failing ? Any ideas ?
I'm pretty sure it's because the txt file you are loading from is so small it is fully read on initialization of the buffered reader.
In my opinion, the file still exists in the reader and the inputStream. Deleting the source file won't change anything until you rerun your application.
BufferedReader and InputStream classes are probaly prepared for similar situations like this. It can be useful if the source of the file goes offline during the run.
Correct me if I'm wrong, I'm not a professional programmer.
FindBugs reports a bug:
Reliance on default encoding
Found a call to a method which will perform a byte to String (or String to byte) conversion, and will assume that the default platform encoding is suitable. This will cause the application behaviour to vary between platforms. Use an alternative API and specify a charset name or Charset object explicitly.
I used FileReader like this (just a piece of code):
public ArrayList<String> getValuesFromFile(File file){
String line;
StringTokenizer token;
ArrayList<String> list = null;
BufferedReader br = null;
try {
br = new BufferedReader(new FileReader(file));
list = new ArrayList<String>();
while ((line = br.readLine())!=null){
token = new StringTokenizer(line);
token.nextToken();
list.add(token.nextToken());
...
To correct the bug I need to change
br = new BufferedReader(new FileReader(file));
to
br = new BufferedReader(new InputStreamReader(new FileInputStream(file), Charset.defaultCharset()));
And when I use PrintWriter the same error occurred. So now I have a question. When I can (should) use FileReader and PrintWriter, if it's not good practice rely on default encoding?
And the second question is to properly use Charset.defaultCharset ()? I decided use this method for automatically defining charset of the user's OS.
Ideally, it should be:
try (InputStream in = new FileInputStream(file);
Reader reader = new InputStreamReader(in, StandardCharsets.UTF_8);
BufferedReader br = new BufferedReader(reader)) {
...or:
try (BufferedReader br = Files.newBufferedReader(path, StandardCharsets.UTF_8)) {
...assuming the file is encoded as UTF-8.
Pretty much every encoding that isn't a Unicode Transformation Format is obsolete for natural language data. There are languages you cannot support without Unicode.
If the file is under the control of your application, and if you want the file to be encoded in the platform's default encoding, then you can use the default platform encoding. Specifying it explicitely makes it clearer, for you and future maintainers, that this is your intention. This would be a reasonable default for a text editor, for example, which would then write files that any other editor on this platform would then be able to read.
If, on the other hand, you want to make sure that any possible character can be written in your file, you should use a universal encoding like UTF8.
And if the file comes from an external application, or is supposed to be compatible with an external application, then you should use the encoding that this external application expects.
What you must realize is that if you write a file like you're doing on a machine, and read it as you're doing on another machine, which doesn't have the same default encoding, you won't necessarily be able to read what you have written. Using a specific encoding, to write and read, like UTF8 makes sure the file will always be the same, whatever platform is used when writing the file.
You should use default encoding whenever you read a file that is outside your application and can be assumed to be in the user's local encoding, for example user written text files. You might want to use the default encoding when writing such files, depending on what the user is going to do with that file later.
You should not use default encoding for any other file, especially application relevant files.
If you application for example writes configuration files in text format, you should always specify the encoding. In general UTF-8 is always a good choice, as it is compatible to almost everything. Not doing so might cause surprise crashes by users in other countries.
This is not only limited to character encoding, but as well to date/time, numeric or other language specific formats. If you for example use default encoding and default date/time strings on a US machine, then try to read that file on a German server, you might be surprised why one half is gibberish and the other half has month/days confused or is off by one hour because of daylight saving time.
When you are using a PrintWriter,
File file = new File(file_path);
Writer w = new OutputStreamWriter(new FileOutputStream(file), StandardCharsets.UTF_16.name());
PrintWriter pw = new PrintWriter(w);
pw.println(content_to_write);
pw.close();
This will work:-
FileReader file = new FileReader(csvFile, Charset.forName("UTF-8"));
BufferedReader csvReader = new BufferedReader(file);
I've had GWT, ext-GWT web-project in utf-8 charset. I've also add utf-8 charset in html file.
Additionally I need to create some pdf report. So that I wrote a special servlet, which take a template html-file, add some information (in local language) and convert a new generated html-file to pdf-file with wkhtmltopdf.
Now, when I try to convert that generated html-file (which also had <meta charset="UTF-8">) to pdf-file, information with local language (some Strings), which I send from client code to servlet is replacing in the result pdf-file with "?" symbol in a black rhomb.
To solve this problem I add some parameters to Process Builder such as "--encoding" "utf-8":
private void ConvertHTMLtoPDF(String sConvertationProgramm, String sHTML, String sPDF)
{
try {
ProcessBuilder pb = new ProcessBuilder(sConvertationProgramm, "--encoding", "utf-8", sHTML, sPDF);
Process process = pb.start();
process.waitFor();
} catch (Exception e) {
e.printStackTrace();
}
}
but all the same, there is no effect at all. At the same time I have those symbols only on tomcat server, without same trouble at jetty.
So, Where is the problem, on the sending local information to the server (cause another information in a local language from template html-file is showed correctly) or when it's writing/converting at the server side?
Does anyone has any suggestions? Thanks
I found my problem. And I have to give my apologises for everyone, because my problem was in the writing new generated html, so instead of using this:
BufferedReader br = new BufferedReader(new InputStreamReader(fis));
BufferedWriter bw = new BufferedWriter(new FileWriter(fHTML));
I must use this:
BufferedReader br = new BufferedReader(new InputStreamReader(fis,"UTF8"));
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fHTML), "UTF-8"));
So, the problem was on reading/writing html-files.
I have got a file in Windows-1250.
I would like to print this file line by line but in Eclipse console I cannot see diacritic signs.
I was trying to make changes in Common tab in run configuration but it gives no results.
I use
BufferedReader reader = new BufferedReader(new FileReader(fileName));
Thank you in advance
Use InputStreamReader or anything that allows specifying the charset:
BufferedReader reader = new BufferedReader(new InputStreamReader(
new FileInputStream(fileName), "Windows-1250"));
may be try to set encoding like this:
PrintStream out = new PrintStream(System.out, true, "Windows-1250");
out.println(message);
may be this helps.
I haven't programmed in java for a while but maybe this class does what you need?
It allows to set charset
The doc of the class you use tells you how to use it.