Efficiency of several concatenated strings. Efficiency of several concatenated strings

Efficiency of several concatenated strings. Efficiency of several concatenated strings

1. Public class test {
3. /**
4. * @ Param args
5. */
6. Public static void main (String [] args ){
7. // TODO Auto-generated method stub
8. Long n = 30000;
9. System. out. println ("Start..." + n );
11. Long start1 = System. currentTimeMillis ();
12. String s1 = new String ("hello ");
13. For (long I = 0; I <n; I ++)
14. {
15. S1 + = "time of concatenating strings ";
16. }
17. Long end1 = System. currentTimeMillis ();
18. Long time1 = end1-start1;
19. System. out. println ("time of concatenating strings with String + =" + time1 );
21. Long start2 = System. currentTimeMillis ();
22. String s2 = new String ("hello ");
23. For (long I = 0; I <n; I ++)
24. {
25. S2 = s2 + "time of String concatenation ";
26. }
27. Long end2 = System. currentTimeMillis ();
28. Long time2 = end2-start2;
29. System. out. println ("String = String + time to splice strings" + time2 );
31. Long start3 = System. currentTimeMillis ();
32. String s3 = new String ("hello ");
33. For (long I = 0; I <n; I ++)
34. {
35. S3 = s3.concat ("concatenation string time ");
36. }
37. Long end3 = System. currentTimeMillis ();
38. Long time3 = end3-start3;
39. System. out. println ("Time to concatenate a String with String. concat" + time3 );
41. Long start4 = System. currentTimeMillis ();
42. StringBuffer s4 = new StringBuffer ("hello ");
43. For (long I = 0; I <n; I ++)
44. {
45. S4.append ("time of String concatenation ");
46. }
47. Long end4 = System. currentTimeMillis ();
48. Long time4 = end4-start4;
49. System. out. println ("Time for concatenating strings with StringBuffer. append" + time4 );
51. Long start5 = System. currentTimeMillis ();
52. StringBuilder s5 = new StringBuilder ("hello ");
53. For (long I = 0; I <n; I ++)
54. {
55. S5.append ("time of String concatenation ");
56. }
57. Long end5 = System. currentTimeMillis ();
58. Long time5 = end5-start5;
59. System. out. println ("Time for concatenating strings with StringBuilder. append" + time5 );
61. System. out. println ("End ...");
62. }
64. }

 

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1. The time for concatenating strings with String + = 27468
2. The time for concatenating strings with String = String + is 25813.
3. The time for concatenating strings with String. concat is 12265.
4. String concatenation time with StringBuffer. append 14
5. Time for concatenating strings with StringBuilder. append 8