Preface

In the use of SQLite preservation URL Address time , It is easy to appear some characters that need escape , Like single quotes （'）、 Percent sign （%） wait . Before saving data sheet records , It is safer to deal with special characters before saving . Generally speaking , Handle “ special ” The escape character of , It is to transform the target string into a standard format . such as , Can be converted to URL encode Encoding or Base64 code , Decode when you need to use the source string . This type of encoding is a permutation encryption , This will not destroy the integrity of the source data and good performance at the same time , It can also structure data , Make the converted data more organized 、 Easy to handle and save . To simplify the description , What is mainly mentioned here is URL encode Coding method .

URL Encoding

URL Encoding will convert some special characters except letters and numbers into Percent sign + 16 Hexadecimal Numbers The format of （ Such as ,%2A）.URL Encoding is also valid for converting Chinese characters .

flow chart

URL Encode

import java.net.URLEncoder
import kotlin.text.Charsets

fun encode(url: String?): String?{
    
	return URLEncoder.encode(url, Charsets.UTF_8.toString())
}

Escape

fun escape(encodedUrl: String?): String?{
    
	return encodedUrl?.replace("%", "/%")?.replace("*", "/*")?.replace("'", "/'")?.replace("_", "/_") } 

Unescape

fun unescape(escapedUrl: String?): String?{
    
	return escapedUrl?.replace("/%", "%")?.replace("/*", "*")?.replace("/'", "'")?.replace("/_", "_") } 

URL Decode

import java.net.URLDecoder

fun decode(unescapedUrl: String?): String?{
    
	return URLDecoder.decode(unescapedUrl, Charsets.UTF_8.toString())
}

note

Use Base64 Encoding special characters that need to be replaced URL Less coding . Both are replacement encryption , There is no essential difference , It is estimated that the efficiency will be different only when the order of magnitude is large .