java 五种字符串拼接的方法及性能介绍

package com.example.sunny.practice_213;public class CutString {//性能最差public String testPlus() {String s = "";for (int i = 0; i < 10000; i++) {s = s + String.valueOf(i);}return s;}//较好public String testConcat() {String s = "";for (int i = 0; i < 10000; i++) {s = s.concat(String.valueOf(i));}return s;}//性能与testStringBuffer相差无几，比其要好public String testJoin() {String[] list = new String[10000];for (int i = 0; i < 10000; i++) {list[i] = String.valueOf(i);}return StringUtils.join(list, "");}public String testStringBuffer() {StringBuffer sb = new StringBuffer();long l1 = System.currentTimeMillis();for (int i = 0; i < 10000; i++){sb.append(String.valueOf(i));}long l2 = System.currentTimeMillis();System.out.println(l2 - l1);return sb.toString();}//性能最高的方法public void testStringBuilder() {StringBuilder sb = new StringBuilder();for (int i = 0; i < 100000; i++) {sb.append(String.valueOf(i));}sb.toString();}public static void main(String[] args) {System.out.println(new CutString().testStringBuffer());}
}