View the class file version at will

Reprinted please indicate the source: http://blog.csdn.net/sunyujia/

I have been busy working recently. I have been playing PSP after work and have not taken care of my blog for a long time. I wanted to check the compiled version of a class file the day before. I felt very troublesome. I need to check the hexadecimal format, so I wrote a small tool last night, just a few lines of code, and there was no research value. I posted it mainly for your convenience. in the future, you don't have to look at hexadecimal.

See http://blog.csdn.net/sunyujia/archive/2008/01/06/2027399.aspx for all version numbers

 

This program

Http://download.csdn.net/source/841562

 

Usage illustration:

The source code is as follows:

1. Package com. syj;
3. Import java. Io. file;
4. Import java. Io. fileinputstream;
5. Import java. Io. ioexception;
7. /**
8. * <P>
9. * Title: class file parser
10. * </P>
11. *
12. * <P>
13. * Copyright: Reprinted please indicate the source http://blog.csdn.net/sunyujia/
14. * </P>
15. *
16. * @ Author Sun Xiaojia
17. * @ Main sunyujia@yahoo.cn
18. * @ Date DEC 4, 2008 9:27:10
19. */
20. Public class classfileparser {
22. /**
23. *
24. * Description: main method for parsing class files
25. *
26. * @ Param File
27. * @ Return
28. * @ Throws ioexception
29. * @ Mail sunyujia@yahoo.cn
30. * @ Since: December 4, 2008 9:31:41
31. */
32. Public static classinfo parse (File file) throws ioexception {
33. Fileinputstream FCM = NULL;
34. Byte [] rs = NULL;
35. Try {
36. FS = new fileinputstream (File );
37. Rs = new byte [8];
38. FS. Read (RS );
39. } Finally {
40. If (FS! = NULL)
41. FCM. Close ();
42. }
43. // System. Out. println ("class file first 8 Bytes:" + byte2hexstring (RS ));
44. Classinfo = new classinfo ();
45. Classinfo. setmajorversion (integer. parseint (
46. Byte2hexstring (New byte [] {Rs [7]}), 16 ));
47. Classinfo. setminorversion (integer. parseint (
48. Byte2hexstring (New byte [] {Rs [5]}), 16 ));
49. Classinfo. setfilepath (file. getabsolutepath ());
50. Classinfo. setdevversion (getdevversion (classinfo. getmajorversion ()));
51. Return classinfo;
52. }
54. /**
55. *
56. * Description: Convert byte array to hexadecimal
57. *
58. * @ Param B
59. * @ Return
60. * @ Mail sunyujia@yahoo.cn
61. * @ Since: December 4, 2008 10:47:31
62. */
63. Public static string byte2hexstring (byte [] B ){
64. Stringbuffer sb = new stringbuffer ();
65. For (INT I = 0; I <B. length; I ++ ){
66. String hex = integer. tohexstring (B [I] & 0xff );
67. If (Hex. Length () = 1 ){
68. Hex = '0' + hex;
69. }
70. SB. append (Hex. touppercase ());
71. }
72. Return sb. tostring ();
73. }
75. /**
76. *
77. * Description: Calculate the development master version number based on the major main version number.
78. *
79. * @ Param m
80. * @ Return
81. * @ Mail sunyujia@yahoo.cn
82. * @ Since: December 4, 2008 10:48:29
83. */
84. Public static string getdevversion (INT m ){
85. Int major = 45;
86. Int devversion = 1;
87. Return string. valueof (devversion + (m-Major + 1)/10f ));
88. }
89. }

1. Package com. syj;
3. Public class classinfo {
4. /**
5. * Main version number
6. */
7. Private int majorversion;
8. /**
9. * Minor version number
10. */
11. Private int minorversion;
12. /**
13. * Class file path
14. */
15. Private string filepath;
16. /**
17. * Development version
18. */
19. Private string devversion;
21. Public int getmajorversion (){
22. Return majorversion;
23. }
25. Public void setmajorversion (INT majorversion ){
26. This. majorversion = majorversion;
27. }
29. Public int getminorversion (){
30. Return minorversion;
31. }
33. Public void setminorversion (INT minorversion ){
34. This. minorversion = minorversion;
35. }
37. Public String getfilepath (){
38. Return filepath;
39. }
41. Public void setfilepath (string filepath ){
42. This. filepath = filepath;
43. }
45. Public String tostring (){
46. Return "Major. Minor:" + majorversion + "." + minorversion + "development version :"
47. + Devversion;
48. }
50. Public String getdevversion (){
51. Return devversion;
52. }
54. Public void setdevversion (string devversion ){
55. This. devversion = devversion;
56. }
57. }

1. Package com. syj;
3. Import java. Io. file;
5. /**
6. * <P>
7. * Title: program entry for viewing the class file version
8. * </P>
9. * <P>
10. * Copyright: Reprinted please indicate the source http://blog.csdn.net/sunyujia/
11. * </P>
12. *
13. * @ Author Sun Xiaojia
14. * @ Main sunyujia@yahoo.cn
15. * @ Date DEC 4, 2008 9:26:39
16. */
17. Public class runner {
18. Public static void main (string [] ARGs) throws exception {
19. If (ARGs = NULL | args. Length = 0 ){
20. System. Out. println ("no file specified ");
21. } Else {
22. Classinfo = classfileparser. parse (new file (ARGs [0]);
23. System. Out. println (classinfo );
24. }
25. }
26. }

Source code for initiating program batch processing:

1. @ Echo off
2. Mode con: Cols = 110 lines = 15
3. : Index
4. Color 27
5. CLS
6. Echo.
7. Echo welcome to the class file version gadgets
8. Echo my blog: http://blog.csdn.net/sunyujia/
9. Echo drag the class file to this window, click the window, and press enter to display the JDK version of the compiled target class file.
10. Echo.
11. Echo.
12. Set route = % Cd %
13. Set Ravel =
14. Set/P Ravel = drag the class file to be viewed:
15. Set "Ravel = % Ravel:" = %"
16. If/I "% Ravel :~ -6% "=". Class "If exist" % Ravel % "Goto go
17. CLS
18. ECHO file error. The specified file does not exist or is not a class file!
19. Echo press any key to re-enter...
20. Echo.
21. Echo.
22. Echo press any key to re-enter...
23. Pause> NUL
24. Goto Index
26. : Go
27. Java-jar versionviewer. Jar % Ravel %
28. Echo.
29. Echo press any key to exit...
30. Pause> NUL
31. Exit