Keyset () and entryset ()

1. ImportJava. util. calendar;
2. ImportJava. util. date;
3. ImportJava. util. hashmap;
4. ImportJava. util. iterator;
5. ImportJava. util. Map. entry;
7. /**
8. * Test the iteration time of keyset () and entryset ().
9. * Keyset (): The key can only be obtained through get () after iteration.
10. * Entryset (): After iteration, you can use E. getkey () and E. getvalue () to get the key and value. The entry interface is returned.
11. * The keyset () is much slower than entryset. It seems that we will consider using entryset () later.
12. * @ Author YL
13. * @ Date 2009.6.10
14. */
15. Public ClassHashmaptest
16. {
17. Public Static VoidMain (string [] ARGs)
18. {
19. Hashmap <string, string> kmap =NewHashmap <string, string> ();
20. Hashmap <string, string> emap =NewHashmap <string, string> ();
22. // Load data
23. For(IntI = 0; I <1000; I ++)
24. {
25. Kmap. Put ("" + I, "yl ");
26. }
27. For(IntI = 0; I <1000; I ++)
28. {
29. Emap. Put ("" + I, "ZT ");
30. }
32. LongStimes = system. currenttimemillis ();
33. LongCtimes = calendar. getinstance (). gettimeinmillis ();
34. LongDtimes =NewDate (). gettime ();
36. // In the initial time, I used three value methods and finally found that system. currenttimemillis (); is the most direct value method.
37. System. Out. println (stimes + "" + ctimes + "" + dtimes );
39. Iterator <string> ktor = kmap. keyset (). iterator ();
40. While(Ktor. hasnext ())
41. {
42. System. Out. println (ktor. Next ());
43. }
45. LongStimes1 = system. currenttimemillis ();
46. LongCtimes1 = calendar. getinstance (). gettimeinmillis ();
47. LongDtimes1 =NewDate (). gettime ();
49. // End the world and entryset Start Time
50. System. Out. println (stimes1-stimes) + "" + (ctimes1-ctimes) + "+ (dtimes1-dtimes ));
51. System. Out. println (stimes1 + "" + ctimes1 + "" + dtimes1 );
53. Iterator <entry <string, string> itor = emap. entryset (). iterator ();
54. While(Itor. hasnext ())
55. {
56. Entry <string, string> E = itor. Next ();
57. // System. Out. println (E. getkey ());
58. System. Out. println (E. getvalue ());
59. }
61. LongStimes2 = system. currenttimemillis ();
62. LongCtimes2 = calendar. getinstance (). gettimeinmillis ();
63. LongDtimes2 =NewDate (). gettime ();
64. System. Out. println (stimes2 + "" + ctimes2 + "" + dtimes2 );
65. System. Out. println (stimes2-stimes1) + "" + (ctimes2-ctimes1) + "+ (dtimes2-dtimes1 ));
66. }
67. }