How do you replace text in a file in Java?

How do you replace text in a file in Java?

Invoke the replaceAll() method on the obtained string passing the line to be replaced (old line) and replacement line (new line) as parameters. Instantiate the FileWriter class. Add the results of the replaceAll() method the FileWriter object using the append() method.

How do you replace a specific string in a text file?

Step 1 : Create a File object by passing the path of the file to be modified. Step 2 : Initialize oldContent with an empty string. This String object will hold all the old content of the input text file. Step 3 : Create BufferedReader object to read the input text file line by line.

How do I replace a text file in Java 8?

Step 1: Create a method which the contain the combination of old word and the new word. Step 2: Create another method which loops the Map key, replace with its value and assign to the String . Step 3: Read the file location, instantiate the Stream and call these methods in the main method.

How do I change the first line of a file in Java?

First use BufferedReader ‘s readLine() to read the first line. Modify it and write it to the BufferedWriter . Then use a char[] array to perform a brute-force copy of the remainder of the file. This will be more efficient than doing the copy line by line.

How do you replace all words in Java?

To replace all words with another String using Java Regular Expressions, we need to use the replaceAll() method. The replaceAll() method returns a String replacing all the character sequence matching the regular expression and String after replacement.

How can I search and replace a file in Java?

As always, it depends on the complexity of your search/replace requirements. You can use Java’s Scanner class to parse words of a file and process them in your application, and then use a BufferedWriter or FileWriter to write back to the file, applying the changes.

How to find and replace file content using Java 8 stream API?

Below example demonstrate how to find and replace file content using Java 8 Stream API. Files.lines (path) – Read all lines from a file as a Stream. line -> line.replaceAll (“foo”, “bar”) – Replace each occurrence of “foo” word with “bar” word in the stream. Files.write () Write lines of text to a file.

How to replace all ‘new’ words with ‘old’ in a text file?

Using replaceAll method, we replaced all ‘new’ words with ‘old’ and save it in modifiedFileContent variable. Next, using BufferedWriter , open the same file. Write the modified strings to the file. Finally, close the BufferedReader and BufferedWriter objects. Suppose the input file contains the following lines :

How to modify the content of a text file?

We are defining one method called modifyFile (). This method reads all the content of input text file into a String object, replaces the old string with new string and rewrites the new content back into the same file.