Feb 15, 2017 · If you are using Java 7 or higher and if lineNumber starts in 1, you can do the following: public static void setVariable(int lineNumber, String data) throws IOException { Path path = Paths.get("data.txt"); List<String> lines = Files.readAllLines(path, StandardCharsets.UTF_8); lines.set(lineNumber - 1, data); Files.write(path, lines ...

Nov 18, 2013 · At the bottom, I have a general solution to replace lines in a file. But first, here is the answer to the specific question at hand. Helper function: try { // input the file content to the StringBuffer "input" BufferedReader file = new BufferedReader(new FileReader("notes.txt")); StringBuffer inputBuffer = new StringBuffer(); String line;

In your above code this would be first replace true with false: BufferedWriter wr = new BufferedWriter(new FileWriter(file, false)); Second, always write to the file, as other lines would then get lost: if(line.contains(id)) { ... line = line.replaceAll(extractText(line), newText); } …

Replacing a specific line in a text file in Java involves reading the entire file, modifying the intended line, and then writing the changes back to the file. This process ensures that the new content replaces the target line effectively while maintaining the integrity of the other lines.

Jan 10, 2025 · To specify these values yourself, construct an OutputStreamWriter on a FileOutputStream. FileWriter is meant for writing streams of characters. For writing streams of raw bytes, consider using a FileOutputStream. FileWriter creates the output file if it is not present already. FileWriter extends OutputStreamWriter and Writer classes.

Feb 2, 2021 · This is the first solution to find and replace a given string with a new string in a file. This approach uses the FileReader, BufferedReader, FileWriter, BufferedWriter, and StringBuffer methods. * using the string buffer methods. Call the function parseEachLine() */ This is line one with language word available. The second line has no such word.

In Java, you can use the FileWriter class to replace the content of a file. Here is an example code: import java.io.FileWriter; import java.io.IOException; public class FileContentReplacementExample { public static void main(String[] args) { // 定义要替换的文件路径 String filePath = "path/to/file.txt"; // 定义要替换的内容和新的内容 String oldContent = "Hello";

BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(outFile)); try {String line; while ((line = bufferedReader.readLine()) != null) {bufferedWriter.write(matchAndReplace(line)); bufferedWriter.newLine();}} finally {bufferedReader.close(); bufferedWriter.flush(); bufferedWriter.close();}} public static void main(String[] args ...

Oct 14, 2019 · Learn how to overwrite a specific line in a text file using Java with step-by-step guidance and code examples.

Jan 23, 2020 · If you want to replace the file, you have to set append to false: However, this replaces the entire file not just the first line. If you are using a recent version of Java, you can do this: Writer writer = new FileWriter("newfile.txt")) { String firstLine = reader.readLine(); firstLine = Integer.toString(Integer.parseInt(firstLine) + 1);