Java中StringBuilder.append和直接用String+String的效率比较

Reference: http://book.csdn.net/bookfiles/135/1001354628.shtml

public class AppendStringTest{ public static void main(String [] args){ String text = ""; long beginTime = System.currentTimeMillis(); for(int i = 0; i < 10000; i++){ text += i; } long endTime = System.currentTimeMillis(); System.out.println("Running time:" + (endTime - beginTime)); StringBuilder builder = new StringBuilder(""); beginTime = System.currentTimeMillis(); for(int i = 0; i < 10000; i++){ builder.append(String.valueOf(i)); } endTime = System.currentTimeMillis(); System.out.println("Runing time:" + (endTime - beginTime)); } }

Results:

注意到随着操作进行的次数增多，差距会更加明显。