public class MainTest { public static void main(String[] args) { long n = 30000; System.out.println("Start... "+n); long start1 = System.currentTimeMillis(); String s1 = new String("hello"); for (long i = 0; i < n; i++) { s1+="拼接字符串的时间"; } long end1 = System.currentTimeMillis(); long time1 = end1 -start1; System.out.println("用String+=拼接字符串的时间"+time1); long start2 = System.currentTimeMillis(); String s2 = new String("hello"); for (long i = 0; i < n; i++) { s2=s2+"拼接字符串的时间"; } long end2 = System.currentTimeMillis(); long time2 = end2 -start2; System.out.println("用String=String+拼接字符串的时间"+time2); long start3 = System.currentTimeMillis(); String s3 = new String("hello"); for (long i = 0; i < n; i++) { s3=s3.concat("拼接字符串的时间"); } long end3 = System.currentTimeMillis(); long time3 = end3 -start3; System.out.println("用String.concat拼接字符串的时间"+time3); long start4 = System.currentTimeMillis(); StringBuffer s4 = new StringBuffer("hello"); for (long i = 0; i < n; i++) { s4.append("拼接字符串的时间"); } long end4 = System.currentTimeMillis(); long time4 = end4 -start4; System.out.println("用StringBuffer.append拼接字符串的时间"+time4); long start5 = System.currentTimeMillis(); StringBuilder s5 = new StringBuilder("hello"); for (long i = 0; i < n; i++) { s5.append("拼接字符串的时间"); } long end5 = System.currentTimeMillis(); long time5 = end5 -start5; System.out.println("用StringBuilder.append拼接字符串的时间"+time5); System.out.println("End..."); } }
输出结果:
Start... 30000
用String+=拼接字符串的时间32800
用String=String+拼接字符串的时间30609
用String.concat拼接字符串的时间14144
用StringBuffer.append拼接字符串的时间2
用StringBuilder.append拼接字符串的时间2
End...