自己编写HashCodeBuilder类
jakarta-commons-lang已经实现了HashCodeBuilder类，据闻在Hibernate中出错，所以还是选择了自己实现，编码思想来源于 Effective java 一书。而且0依赖。

java 代码?

1. import?java.lang.reflect.Array;??
2. ??
3. public?class?HashCodeBuilder?{??
4. ????public?HashCodeBuilder()?{??
5. ??
6. ????}??
7. ??
8. ????private?int?result?=?17;??
9. ??
10. ????public?HashCodeBuilder?append(boolean?field)?{??
11. ????????result?=?37?*?result?+?(field???1?:?0);??
12. ????????return?this;??
13. ????}??
14. ??
15. ????public?HashCodeBuilder?append(byte?field)?{??
16. ????????result?=?37?*?result?+?(int)?field;??
17. ????????return?this;??
18. ????}??
19. ??
20. ????public?HashCodeBuilder?append(char?field)?{??
21. ????????result?=?37?*?result?+?(int)?field;??
22. ????????return?this;??
23. ????}??
24. ??
25. ????public?HashCodeBuilder?append(short?field)?{??
26. ????????result?=?37?*?result?+?(int)?field;??
27. ????????return?this;??
28. ????}??
29. ??
30. ????public?HashCodeBuilder?append(int?field)?{??
31. ????????result?=?37?*?result?+?field;??
32. ????????return?this;??
33. ????}??
34. ??
35. ????public?HashCodeBuilder?append(long?field)?{??
36. ????????result?=?37?*?result?+?(int)?(field?^?(field?>>>?32));??
37. ????????return?this;??
38. ????}??
39. ??
40. ????public?HashCodeBuilder?append(float?field)?{??
41. ????????result?=?37?*?result?+?Float.floatToIntBits(field);??
42. ????????return?this;??
43. ????}??
44. ??
45. ????public?HashCodeBuilder?append(double?field)?{??
46. ????????append(Double.doubleToLongBits(field));??
47. ????????return?this;??
48. ????}??
49. ??
50. ????public?HashCodeBuilder?append(Object?field)?{??
51. ????????if(field?==?null)??
52. ????????????result?=?0;??
53. ????????else?if?(field.getClass().isArray())?{??
54. ????????????for?(int?i?=?Array.getLength(field)?-?1;?i?>=?0;?i--)?{??
55. ????????????????append(Array.get(field,?i));??
56. ????????????}??
57. ????????}?else??
58. ????????????append(field.hashCode());??
59. ????????return?this;??
60. ????}??
61. ??
62. ????public?int?toHashCode()?{??
63. ????????return?result;??
64. ????}??
65. ??????
66. ????@Override??
67. ????public?int?hashCode()?{??
68. ????????return?result;??
69. ????}??
70. ??????
71. ????@Override??
72. ????public?String?toString()?{??
73. ????????return?String.valueOf(result);??
74. ????}??
75. ??
76. }??

测试代码

java 代码?

1. public?class?MyBean?{??
2. ????Long?id;??
3. ????String?name;??
4. ????char[]?chars;??
5. ????public?MyBean(Long?id,?String?name,?char[]?chars)?{??
6. ????????super();??
7. ????????this.id?=?id;??
8. ????????this.name?=?name;??
9. ????????this.chars?=?chars;??
10. ????}??
11. ??????
12. ????@Override??
13. ????public?int?hashCode()?{??
14. ????????return?new?HashCodeBuilder().append(id)??
15. ????????????????????.append(name).append(chars).hashCode();??
16. ????}??
17. ??????
18. ????public?static?void?main(String[]?args)?{??
19. ????????MyBean?bean1?=?new?MyBean(Long.valueOf(10),??
20. ????????????????"名称",new?char[]{'a','b','c','d','e'});??
21. ????????MyBean?bean2?=?new?MyBean(Long.valueOf(10),??
22. ????????????????"名称",new?char[]{'a','b','c','d','e'});??
23. ????????System.out.println("bean1.hashCode="+bean1.hashCode());??
24. ????????System.out.println("bean2.hashCode="+bean2.hashCode());??
25. ????}??
26. }??

1 楼 v38 2007-03-14 <br/>
<strong>jasongreen 写道：</strong><br/>
<div class='quote_div'>jakarta-commons-lang已经实现了HashCodeBuilder类，据闻在Hibernate中出错，所以还是选择了自己实现，编码思想来源于 Effective java 一书。而且0依赖。<br/>
==========================</div>
<div class='quote_div'>jakarta-commons-lang已实现的HashCodeBuilder类的错误没有把我们给折磨死～</div>
<div class='quote_div'><br/>
<br/>
<br/>
<br/>
</div> 2 楼 jasongreen 2007-03-15 我没有用过common-lang，不是太清楚，我最近在写crazyPOJO的项目，通过Annotation标志value field，然后根据value field生成hashCode，生成equals，生成clone，生成toString，生成toXML，生成toJSON，进行中，今天已经实现了，hashCode和equals，clone等方法，一会上传，大家试用一下