1. Reading and writing files
Now, let's explore the importance of file reading and writing in Java. It enables efficient data storage, retrieval, and processing, ensuring smooth and reliable data management while avoiding issues like data corruption or loss.
2. Casting
Before we start reading data, we need to understand the concept of casting. It allows us to convert between different primitive types.
When converting a smaller type, like `byte`, to a larger one, like `int`, the process happens automatically. This is called widening casting.
But when converting a larger type to a smaller one, for example, from `double` to `int`, we need to specify the new type in parentheses. This is called narrowing casting.
3. Understanding specific casting for reading file
We can also cast `int` to `char` using the same narrowing casting. This is useful because characters are represented by Unicode values.
For example, casting the integer `97` to `(char)` results in `a`, converting a number into a readable character.
4. Reading data from a file using FileReader
`FileReader` is a simple class for reading text files character by character, ideal for small files as it processes data sequentially.
In this example, we first import the `FileReader` class.
Then we create a `FileReader` object to read characters from `example.txt`, printing each one until the end, which is signaled by a return value of -1.
Closing the file with `.close()` is crucial to release system resources and ensure smooth performance.
5. Efficient reading with BufferedReader
For larger files, `BufferedReader` is more efficient. It reads text line by line instead of character by character.
A `FileReader` accesses the file, while a `BufferedReader` wraps it to improve efficiency by reading larger data chunks and reducing disk access.
The `.readLine()` method reads each line until the end, indicated by null.
6. Writing data using FileWriter
We can use `FileWriter` to write data to files. By default, it overwrites the file's content, starting from the beginning and replacing any existing data. This should be used carefully to avoid unintentional data loss.
To use `FileWriter`, we need to import the `FileWriter` class.
We first create a new `FileWriter` instance for the file `example.txt`.
The `.write()` method is then used to actually write data into the file.
7. Appending data using FileWriter
If we don't want to overwrite the file, `FileWriter` also supports an append mode, which allows new content to be added without affecting the original data.
In the example, a new instance `FileWriter` is created with the second argument set to true to enable append mode. This ensures that the new text is added to the end of the file, preserving the existing content.
8. Efficient writing with BufferedWriter
To write text more efficiently, use `BufferedWriter` with `FileWriter`.
It works like before—import the classes, write your content, and close the writer when done. The key difference? `BufferedWriter` reduces write operations by handling larger chunks of text, and the `.newLine()` method makes adding line breaks easy.
9. Let's practice!
Now that we have covered the basics of reading and writing text files in Java, it is time to put these concepts into practice