Java regex validate date format examples

This article shows how to use regex + code to validate a date format, support single and leading zero month and day format (1 or 01), check for the 30 or 31 days of the month, and leap year validation. Below are the requirements for a valid date. Year format, 1900, 2099 regex Month format, …

Read more

How to read a UTF-8 file in Java

In Java, the InputStreamReader accepts a charset to decode the byte streams into character streams. We can pass a StandardCharsets.UTF_8 into the InputStreamReader constructor to read data from a UTF-8 file. import java.nio.charset.StandardCharsets; //… try (FileInputStream fis = new FileInputStream(file); InputStreamReader isr = new InputStreamReader(fis, StandardCharsets.UTF_8); BufferedReader reader = new BufferedReader(isr) ) { String str; …

Read more

How to write a UTF-8 file in Java

In Java, the OutputStreamWriter accepts a charset to encode the character streams into byte streams. We can pass a StandardCharsets.UTF_8 into the OutputStreamWriter constructor to write data to a UTF-8 file. try (FileOutputStream fos = new FileOutputStream(file); OutputStreamWriter osw = new OutputStreamWriter(fos, StandardCharsets.UTF_8); BufferedWriter writer = new BufferedWriter(osw)) { writer.append(line); } In Java 7+, many …

Read more

How to read file in Java – BufferedReader

In this article, we will show you how to use java.io.BufferedReader to read content from a file Note Read this different ways read a file 1. Files.newBufferedReader (Java 8) In Java 8, there is a new method Files.newBufferedReader(Paths.get(“file”)) to return a BufferedReader filename.txt A B C D E FileExample1.java package com.mkyong; import java.io.BufferedReader; import java.io.IOException; …

Read more