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Perbedaan antara String, StringBuffer dan StringBuilder di Java – Contoh terlampir

Diterbitkan: 2022-01-30
Perbedaan antara String, StringBuffer dan StringBuilder di Java - Perbandingan dan Contoh terlampir

Dalam tutorial Java ini kita akan membahas perbedaan antara Java String, StringBuffer dan StringBuilder.

Mari kita mulai:

Rangkaian:

Kelas String mewakili string karakter. Semua literal string dalam program Java, seperti "crunchify", diimplementasikan sebagai instance dari kelas ini. String adalah konstan; nilainya tidak dapat diubah setelah dibuat.

StringBuffer:

Urutan karakter yang aman dan dapat diubah. Buffer string seperti String, tetapi dapat dimodifikasi.

Setiap saat itu berisi beberapa urutan karakter tertentu, tetapi panjang dan isi urutan dapat diubah melalui pemanggilan metode tertentu.

Buffer string aman untuk digunakan oleh banyak utas.

StringBuilder:

Urutan karakter yang bisa berubah. Kelas ini menyediakan API yang kompatibel dengan StringBuffer, tetapi tanpa jaminan sinkronisasi.

Kelas ini dirancang untuk digunakan sebagai pengganti drop-in untuk StringBuffer di tempat buffer string digunakan oleh satu utas (seperti yang umumnya terjadi).

Jika memungkinkan, direkomendasikan bahwa kelas ini digunakan dalam preferensi untuk StringBuffer karena akan lebih cepat di sebagian besar implementasi.

Mari kita bandingkan semua karakteristik String, StringBuffer dan StringBuilder di bawah ini.

Rangkaian StringBuffer StringBuilder
Benang aman? Ya Ya Tidak
Disinkronkan? Ya Ya Tidak
Dapat dimodifikasi? Tidak (tidak berubah) Ya (bisa berubah) Ya (bisa berubah)
Penyimpanan String Pool Tumpukan Tumpukan
Pertunjukan Lambat Cepat Lebih cepat

kode Jawa:

  • Buat kelas: CrunchifyStringVsStringBufferVsStringBuilder.java
  • Masukkan kode di bawah ini ke dalamnya
  • Menyimpan file

Dalam tutorial ini, kami menambahkan penambahan, penambahan string total 199999 kali.

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package crunchify . com . tutorial ;
 
/**
* @author Crunchify.com
* Program: Difference between String, StringBuffer and StringBuilder in Java - Example attached
*/
 
public class CrunchifyStringVsStringBufferVsStringBuilder {
 
     public static void main ( String [ ] args ) {
 
         // String: The String class represents character strings. All string literals
         // in Java programs, such as "abc", are implemented as instances of this class.
         // Strings are constant; their values cannot be changed after they are created. String buffers support mutable strings.
         // Because String objects are immutable they can be shared.
         String crunchifyString = "" ;
         long crunchifyBefore = System . currentTimeMillis ( ) ;
         for ( int i = 0 ; i < 199999 ; i ++ ) {
             crunchifyString = crunchifyString + "crunchify.com" ;
         }
 
         long crunchifyAfter = ( System . currentTimeMillis ( ) ) ;
         crunchifyPrint ( "Task Completion Time for String: " + ( crunchifyAfter - crunchifyBefore ) ) ;
 
         // StringBuffer: A thread-safe, mutable sequence of characters. A string buffer is like a String,
         // but can be modified. At any point in time it contains some particular sequence of characters, but the length
         // and content of the sequence can be changed through certain method calls.
         //
         // String buffers are safe for use by multiple threads. The methods are synchronized where necessary so that all
         // the operations on any particular instance behave as if they occur in some serial order that is consistent with the order
         // of the method calls made by each of the individual threads involved.
         //
         // The principal operations on a StringBuffer are the append and insert methods,
         // which are overloaded so as to accept data of any type. Each effectively converts a given datum to a string and then appends
         // or inserts the characters of that string to the string buffer.
         // The append method always adds these characters at the end of the buffer;
         // the insert method adds the characters at a specified point.
 
         crunchifyBefore = System . currentTimeMillis ( ) ;
         StringBuffer crunchifyStringBuffer = new StringBuffer ( ) ;
         for ( int i = 0 ; i < 199999 ; i ++ ) {
             crunchifyStringBuffer . append ( "crunchify.com" ) ;
         }
 
         crunchifyAfter = ( System . currentTimeMillis ( ) ) ;
         crunchifyPrint ( "Task Completion Time for StringBuffer: " + ( crunchifyAfter - crunchifyBefore ) ) ;
 
         // StringBuilder: A mutable sequence of characters.
         // This class provides an API compatible with StringBuffer, but with no guarantee of synchronization.
         // This class is designed for use as a drop-in replacement for StringBuffer in places where the string buffer was being used by a single thread
         // (as is generally the case). Where possible,
         // it is recommended that this class be used in preference to StringBuffer as it will be faster under most implementations.
         //
         // The principal operations on a StringBuilder are the append and insert methods,
         // which are overloaded so as to accept data of any type. Each effectively converts a given datum to a string and then appends
         // or inserts the characters of that string to the string builder.
         // The append method always adds these characters at the end of the builder; the insert method adds the characters at a specified point.
 
         crunchifyBefore = System . currentTimeMillis ( ) ;
         StringBuilder crunchifyStringBuilder ;
         crunchifyStringBuilder = new StringBuilder ( ) ;
 
         for ( int i = 0 ; i < 199999 ; i ++ ) {
             crunchifyStringBuilder . append ( "crunchify.com" ) ;
         }
         // OR using repeat().
         // crunchifyStringBuilder.append("crunchify.com".repeat(199999));
         // repeat(): Returns a string whose value is the concatenation of this string repeated count times.
 
         crunchifyAfter = ( System . currentTimeMillis ( ) ) ;
         crunchifyPrint ( "Task Completion Time for StringBuilder: " + ( crunchifyAfter - crunchifyBefore ) ) ;
 
     }
 
     private static void crunchifyPrint ( String s ) {
         System . out . println ( s ) ;
     }
}
 

Hasil Konsol IntelliJ IDEA:

Jalankan program di atas sebagai Aplikasi Java di IntelliJ IDEA atau di Eclipse Console dan Anda akan menghasilkan seperti di bawah ini.

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/ Users / app / app / Installation / jdk - 17.0.2.jdk / Contents / Home / bin / java - javaagent : / Applications / IntelliJ IDEA . app / Contents / lib / idea_rt . jar = 50109 : / Applications / IntelliJ IDEA . app / Contents / bin - Dfile . encoding = UTF - 8 - classpath : / Users / app / . m2 / repository / org / slf4j / log4j - over - slf4j / 1.7.32 / log4j - over - slf4j - 1.7.32.jar crunchify . com . tutorial . CrunchifyStringVsStringBuffer
 
Task Completion Time for String : 19648
Task Completion Time for StringBuffer : 7
Task Completion Time for StringBuilder : 3
 
Process finished with exit code 0
 

Beri tahu saya jika Anda menghadapi masalah saat menjalankan program di atas atau memiliki pertanyaan antara String, StringBuffer, dan StringBuilder.