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String.length() vs String.getBytes().length in Java

In Java, String.length() is to return the number of characters in the string, while String.getBytes().length is to return the number of bytes to represent the string with the specified encoding. By default, the encoding will be the value of system property file.encoding, the encoding name can be set manually as well by calling System.setProperty("file.encoding", "XXX"). For example, UTF-8, Cp1252. In many cases, String.length() will return the same value as String.getBytes().length, but in some ...

Java,UTF8,String,Encoding,Sample 2015-04-01 22:22:23

Use Java ThreadLocal with caution

According to Oracle documentation, ThreadLocal is a class provides thread-local variables. These variables differ from their normal counterparts in that each thread that accesses one (via its get or set method) has its own, independently initialized copy of the variable. ThreadLocal instances are typically private static fields in classes that wish to associate state with a thread. In short, ThreadLocal variables are variables belong to a thread, not a class or an instance of a class. One common...

JAVA,MEMORY LEAK, THREADLOCAL 2015-11-03 07:31:57

File upload once again

File upload is one of the oldest operation of web design. After 20 years, it's still has no big change, difficult to handle, lack of interaction and poor user experience. Web developers have thought many methods to improve the experience of uploading file in web apps, they developed various plugins based on different JavaScript libraries. However, because of the difference among different web browsers, there is no common interface which makes these plugins work properly or easily on all web brow...

Web design, File upload, Asynchronous,HTML5 2012-09-02 11:52:21

Best practices of front end optimization

1. Use DocumentFragment or innerHTML to replace complex elements insertion DOM operation on browser is expensive. Although browser performance is improved much, multiple DOM elements insertion is still expensive and will affect the page load speed. Assume we have an ul element on our page, we now want to retrieve a JSON list using AJAX and then update the ul using JavaScript. Usually we may write it as : var list = document.querySelector('ul'); ajaxResult.items.forEach(function(item) { // ...

JavaScript,Front end,Optimization,Tips 2013-07-06 11:26:27

Big file transfer in Linux

It's very common that we need to transfer files between two different hosts such as backups. It is also an very simple task, we can use scp or rsync to complete the task well. But what if the file is very big, it may take some time to transfer it. How can we transfer a big file with high speed? Here we propose one solution. Copy file If we copy one uncompressed file, then we should follow below steps: Compress data Send it to another host Uncompress the data Verify the data integrity This will...

Linux, SCP,ZIP 2013-01-10 05:55:50

Spring â€“ Web sockets in Java Development

Experts of java development team are sharing this article with entire java development community. The purpose behind intending this post is to explain spring – Web sockets as a concept to rest of the world. Technology: Web socket is the one of the protocol supported by web-browsers and web-servers. It provides the two-way communication between client and server. It is used in any Java application for providing the two way communication between client and server. It opens a connection betw...

JAVA DEVELOPMENT,SPRING,JAVA TECHNOLOGY 2016-09-13 03:56:54

The Go Pointer Magic

Go is a language with the pointer type, by which we can Pass pointer into a function and update value in-place. Add methods to a struct as (* T) A, which is different from (T) A(). However, the pointer is type-safe in Go, meaning that there are such restrictions of the pointer. Different types of pointers are unconvertible. Pointer type cannot be used for calculation. Pointer types cannot be compared, either == nor !=. No mutual assignment between different pointer-...

GOLANG,POINTER,UNSAFE 2021-10-03 02:18:57

Set Real-Time Clock Unit for OT/IoT Device

Configure DS1307 RTC on BeagleBone-Black Arduino or Raspberry-PI Figure-00: Project Overview Diagram , version v0.1.2 (2024) Program Design Purpose: Real-Time Clock (RTC) modules are essential for maintaining accurate timekeeping in various applications, including system clocks, data logging, and alarm systems. In scenarios where devices operate offline, such as a ship's NMEA 0183 data recorder that logs engine and rudder data, or an RTU (Remote Terminal Unit) with real time state change config...

2024-08-18 03:09:06

4 deployment modes of Redis

As a high-performance in-memory database, Redis is widely used in current mainstream distributed architecture systems. To improve system fault tolerance, using multiple instances of Redis is also inevitable, but the complexity is much higher than that of a single instance. This article mainly introduces the four deployment modes of Redis and their advantages and disadvantages. Standalone Standalone mode is to install a Redis, start it, and business connects to it and that's all. The specific ...

REDIS,STANDALONE,MASTER-SLAVE,SENTINEL,CLUSTER 2023-03-03 21:35:09