Reusable String Builder - StrBuilder

Introduction

In the StringBuilder provided by the JDK, string concatenation becomes more efficient and flexible, but generating a new string requires rebuilding the StringBuilder object, which results in performance loss and memory waste. Therefore, Hutool provides a reusable StrBuilder.

Usage

StrBuilder has the same usage as StringBuilder, except that it has a reset method to rebuild a new string without allocating new memory.

StrBuilder builder = StrBuilder.create();
builder.append("aaa").append("你好").append('r');
// Result: aaa你好r

Performance Test for Building Strings Multiple Times

We simulated creating 1,000,000 strings to compare the performance of the two, using TimeInterval timing:

// StringBuilder
TimeInterval timer = DateUtil.timer();
StringBuilder b2 = new StringBuilder();
for (int i = 0; i < 1000000; i++) {
 b2.append("test");
 b2 = new StringBuilder();
}
Console.log(timer.interval());

    
  

// StrBuilder
TimeInterval timer = DateUtil.timer();
StrBuilder builder = StrBuilder.create();
for (int i = 0; i < 1000000; i++) {
 builder.append("test");
 builder.reset();
}
Console.log(timer.interval());

    
  

The test result is:

StringBuilder: 39ms
StrBuilder   : 20ms

The performance is almost doubled. Users are welcome to test it themselves.

CsvUtil UnicodeUtil