How Can I Efficiently Access a Specific Line in a Java File?

Accessing a Specific Line in a File in Java

In Java, accessing a specific line from a text file requires specialized techniques, particularly when dealing with large files. This article explores two methods for extracting a specific line from a file based on line number:

Small Files:

For smaller files, a simple approach involves loading the entire file content into memory and accessing the line using the get() method with the line number as the index. This can be done using the readAllLines() method like so:

String line32 = Files.readAllLines(Paths.get("file.txt")).get(32);

Large Files:

However, for larger files, reading the entire file into memory may not be feasible. In such cases, it's more efficient to stream the file line by line and skip to the desired line number. Using Java's NIO.2 package, this can be achieved as follows:

try (Stream<String> lines = Files.lines(Paths.get("file.txt"))) {
    line32 = lines.skip(31).findFirst().get();
}

In this approach, skip(31) moves the stream to line 32, and findFirst().get() retrieves the line as a String object.

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