I need to read contents of a file as a server, and then send the read data file, for the client so the client print it out on the Client terminal.
The problem is that I can't find a way or method to read a txt file from the current directory which my java file and txt file are existed.
Please help me.
There are many ways to read text file or file in java. It depend on you to that in which format you need to pass your file content to client side.
Here are some method to reading file in java.
1. Using BufferedReader class
BufferedReader input = new BufferedReader(new FileReader(aFile));
String line = null; //not declared within while loop
while (( line = input.readLine()) != null){
String curLine = line;
//Process line
}
2.Using Apache Common IOUtils with the class IOUtils.toString() method.
FileInputStream inputStream = new FileInputStream("FILEPATH/FILENAME");
try {
String everything = IOUtils.toString(inputStream);
} finally {
inputStream.close();
}
3.Using the Scanner class in Java and the FileReader
Scanner in = new Scanner(new FileReader("FILENAME/FILEPATH"));
while (scanner.hasNextLine()){
//process each line in some way
String line = scanner.nextLine();
}
Scanner has several methods for reading in strings, numbers, etc...
4.In JAVA 7 this is the best way to simply read a textfile
new String(Files.readAllBytes(...))
or Files.readAllLines(...)
Path path = Paths.get("FILENAME");
List<String> allLines = Files.readAllLines(path, ENCODING);
Please refer this link for more onfomation.
You can use BufferedReader to read from a txt file.
BufferedReader br = new BufferedReader(new FileReader(fileName));
String line = br.readLine();
here fileName is a string that contain your absolute file name.
eg : fileName = "C:\temp\test.txt";
You can read file by using BufferedReader.
File file=new File("filepath");
BufferedReader br=new BufferedReader(new FileReader(file)); //Here you create an object of bufferedreader which file read through filereader
String data=br.readLine();
while(data!=null)
{
System.out.println(data); // Writing in the console
data=br.readLine();
}
This will taking input from file and giving output to console.If you want it write in other file then use BufferedWriter.
File out=new File("outputfilepath");
BufferedWriter bw=new BufferedWriter(new FileWriter(out));
simply us bw.write() instead of System.out.println();.
Related
So I wrote this file reader method that should return a string of everything that is in the file, but it isn't working properly. Writing into the file works perfectly, but this reading method doesn't. What the method does currently is it reads the last string/text added, but it does not read the file from start to finish. 'br' is my bufferedReader, which is declared somewhere else in the same class.
Here's how br is defined:
private static FileInputStream fis;
private static BufferedReader br;
and then in the constructor:
fis = new FileInputStream(file);
br = new BufferedReader(new InputStreamReader(fis));
Here's the method:
public String readStuff(){
String line = "";
String r = "";
try{
while((line = br.readLine()) != null){
System.out.println(line + " read ");
r+= line;
}
//br.close(); JDK 7 does this automatically apparently
}catch(IOException e){
e.printStackTrace();
System.out.println("Error at readStuff!");
}
return r;
I know I'm making either a logic mistake or some obvious error, I just don't know where.
If you want to read the entire file twice, you will have to close it and open new streams/readers next time.
Those streams/readers should be local to the method, not members, and certainly not static.
Using File and FileReader You can Read / Write File From Dir.
you can get File using File class object
File file = new File("file.txt");
and After Process to read that file
FileReader fr = new FileReader(file);
There are Whole Code to read File...
File file = new File("G:\\Neon\\data.txt");
FileReader fr = new FileReader(file);
String data = "";
while((i = fr.read()) != -1)
{
data = data + (char)i;
}
System.out.println(data);
I am writing a program in Java, it scans a file, counts lines, character, palindromes, words. My problem is when I ask for a filename, I am using BufferedReader and InputStreamReader to scan the file the user provided, and print the results in another file, my program compiles, when I type in the name of the file nothing happens, program does not finish, and remains stuck, here is code the BufferedReader, if the entire code is needed i will post it up
System.out.println("Enter the name of the file you would like to scan: ");
String fileName = scan.nextLine();
File file = new File(fileName);
BufferedReader br = new BufferedReader(newInputStreamReader(System.in));
Scanner scanner = new Scanner(System.in);
String fileName = scanner.next();
scanner.nextLine();
FileReader file = new FileReader(fileName);
BufferedReader br = new BufferedReader(FileReader);
Try with
BufferedReader br = new BufferedReader(new FileReader(fileName));
actually you are specifying your reader InputStreamReader to read from System as System.in though you are trying to read a file. So you have to use FileReader. See How to read file in Java
also thanks to #user1009560 you can use
BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(file)));
You're creating an InputStreamReader object as System.in as the inputStream property. You'll need to specify a FileInputStream for as the InputStream.
I have a text file which I have a BufferedReader read from.
String sCurrentLine;
File myFile = new File("/sdcard/file.txt");
BufferedReader buf = new BufferedReader(new FileReader(myFile));
while ((sCurrentLine = buf.readLine()) != null) {
}
What I want to do is read a specific line and then replace it with something else whilst leaving the rest of the file alone. How should I do this?
Create a temporary file
Read through the file file.txt, write the output to the temporary file making the replacement as necessary
Close the file
Delete/backup the original file
Rename the temporary file to the original file
I am using following code to write json to my local path which i get from my html page.Again I have to construct a html page by reading content from the saved local json file.For this I have to read this saved file from local which is plain text and give as input to java file. I got confused whether to use Buffered Reader or BufferedInputStream to read that file from local path.Please help me.
java.io.BufferedWriter jsonOut = new java.io.BufferedWriter(
new java.io.OutputStreamWriter(
new java.io.FileOutputStream(uploadDir +
_req.getParameter("filename")), "ISO-8859-1"));
BufferedReader for text.
Reason: http://tutorials.jenkov.com/java-io/bufferedreader.html
You can use BufferedReader for text but you should ensure to use the proper charset in your case (otherwise it defaults to the platform charset)
BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(myFile),"ISO-8859-1"));
To read a file you can use the following code
File f = new File("your json file");
BufferedReader buf = new BufferedReader(new FileReader(f));
String line = null;
while ((line = buf.readLine()) != null) {
System.out.println("json file line " + line);
// do your changes
}
How can I delete a specific string in a text file?
Locate the file.
File file = new File("/path/to/file.txt");
Create a temporary file (otherwise you've to read everything into Java's memory first).
File temp = File.createTempFile("file", ".txt", file.getParentFile());
Determine the charset.
String charset = "UTF-8";
Determine the string you'd like to delete.
String delete = "foo";
Open the file for reading.
BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(file), charset));
Open the temp file for writing.
PrintWriter writer = new PrintWriter(new OutputStreamWriter(new FileOutputStream(temp), charset));
Read the file line by line.
for (String line; (line = reader.readLine()) != null;) {
// ...
}
Delete the string from the line.
line = line.replace(delete, "");
Write it to temp file.
writer.println(line);
Close the reader and writer (preferably in the finally block).
reader.close();
writer.close();
Delete the file.
file.delete();
Rename the temp file.
temp.renameTo(file);
See also:
The Java Tutorials - Lesson: basic I/O