String variable interpolation Java

Question

String building in Java confounds me  I abhore doing things like   url     u1     u1     u2     u2     u3     u3     u4     u4        url     x     u1     y     u2     z     u3     da1     u4        url     qty 1 cost     orderTotal     ord     orderId          Or  using StringBuilder  something like this       url append  u1         url append u1       url append   u2         url append u2       url append   u3         url append u3       url append   u4         url append u4       url append           url append  x         url append u1       url append   y         url append u2       url append   z         url append u3       url append   da1         url append u4       url append           url append  qty 1         url append  cost         url append orderTotal       url append   ord         url append orderId       url append         SURELY I m missing something  There has GOT to be a better way  Something like   Instead of   urlString     u1     u1     u2     u2     u3     u3     u4     u4          do   urlString    Interpolator  u1  s u2  s u3  s u4  s    u1  u2  u3  u4     or   urlStringBuilder append Interpolator  u1  s u2  s u3  s u4  s    u1  u2  u3  u4

User · Answer

You can use Kotlin  the Super  cede of  Java for JVM  it has a nice way of interpolating strings like those of ES5  Ruby and Python     class Client val firstName  String  val lastName  String        val fullName     firstName  lastName

User · Answer

Note that there is no variable interpolation in Java  Variable interpolation is variable substitution with its value inside a string  An example in Ruby     usr bin ruby  age   34 name    quot William quot   puts  quot   name  is   age  years old quot   The Ruby interpreter automatically replaces variables with its values inside a string  The fact  that we are going to do interpolation is hinted by sigil characters  In Ruby  it is      In Perl  it could be      or    Java would only print such characters  it would not expand them  Variable interpolation is not supported in Java  Instead of this  we have string formatting  package com zetcode   public class StringFormatting        public static void main String   args                 int age   34          String name    quot William quot            String output   String format  quot  s is  d years old  quot   name  age                System out println output            In Java  we build a new string using the String format   method  The outcome is the same  but the methods are different  See http   en wikipedia org wiki Variable interpolation Edit As of 2019  JEP 326  Raw String Literals  was withdrawn and superseded by multiple JEPs eventually leading to JEP 378  Text Blocks delivered in Java 15   A text block is a multi-line string literal that avoids the need for most escape sequences  automatically formats the string in a predictable way  and gives the developer control over the format when desired   However  still no string interpolation   Non-Goals      Text blocks do not directly support string interpolation  Interpolation may be considered in a future JEP  In the meantime  the new instance method String  formatted aids in situations where interpolation might be desired

User · Answer

Just to add  that there is also java text MessageFormat with the benefit of having numeric argument indexes   Appending the 1st example from the documentation  int planet   7  String event    a disturbance in the Force    String result   MessageFormat format       At  1 time  on  1 date   there was  2  on planet  0 number integer         planet  new Date    event     Result    At 12 30 PM on Jul 3  2053  there was a disturbance in the Force on planet 7

User · Answer

If you re using Java 5 or higher  you can use String format   urlString    String format  u1  s u2  s u3  s u4  s    u1  u2  u3  u4     See Formatter for details

User · Answer

String format   to the rescue

[java] String variable interpolation Java

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