Basic php exception handling methods

The following describes how to handle exceptions in php. For more information about how to handle exceptions, see this tutorial. The following is a reference segment: 1. allow a method to provide a detailed error mark to the client code 2.

The following describes how to handle exceptions in php. For more information about how to handle exceptions, see this tutorial.

The following is a reference clip:

1. allow a method to give an error mark to the customer code

2. provide detailed information about program errors

3. let you determine multiple error conditions at the same time and separate your error report from the program processing process.

4. the return value must be of an independent type and will not be confused with the normal returned type.

Two instances master PHP exception handling

Example [1] use try... catch

The instance code is as follows:

1. /* PDO connects to the mysql database. if you have not read the PDO, first check the PDO constructor. otherwise, skip example 1 and see Example 2 */
2. $ Dsn = 'MySQL: host = localhost; dbname = testdb ';
3. $ User = 'dbuser ';
4. $ Password = 'dbpass ';
5. Try {
6. $ Dbh = new PDO ($ dsn, $ user, $ password); // An exception may occur when you create a database connection object.
7. Echo 'If an exception occurs above, I cannot be displayed ';
8. } Catch (PDOException $ e ){
9. Echo 'connection failed: '. $ e->__ toString ();
10. }
11. ?>

The instance code is as follows:

2. // Example [2] try... cathc and throw
3. Try {
4. $ Error = 'I throw exception information and exit the try block ';
5. If (is_dir ('./tests ')){
6. Echo 'Do something .';
7. } Else {
8. Throw new Exception ($ error, 12345 );
9. }
10. Echo 'if there is an exception above, it won't turn to me !~ ', "N ";
11. } Catch (Exception $ e ){
12. Echo 'capture exception: ', $ e-> getMessage (), $ e-> getCode (), "n "; // Display $ error and 123456
13. }
14. Echo 'continue execution ';
15. ?>

As a friend said above, I wrote some program exercises for myself:

The instance code is as follows:

1. $ A = 20;
2. // Example of using regular catch
3. Try
4. {
5. If ($ a = 1)
6. {
7. Throw new Exception ("I am 1", 1 );
8. }
9. Elseif ($ a = 2)
10. {
11. Throw new Exception ("I am 2", 3 );
12. }
13. Elseif ($ a = 3)
14. {
15. Throw new Exception ("I am 3", 3 );
16. }
17. Elseif ($ a = 4)
18. {
19. Throw new Exception ("I am 4", 4 );
20. }
21. Else
22. {
23. Throw new Exception ("Who am I? ", 0 );
24. }
25. }
26. Catch (Exception $ e)
27. {
28. If ($ e-> getCode () = 1)
29. {
30. Echo "1:". $ e;
31. }
32. Elseif ($ e-> getCode () = 2)
33. {
34. Echo "2:". $ e;
35. }
36. Elseif ($ e-> getCode () = 3)
37. {
38. Echo "3:". $ e;
39. }
40. Elseif ($ e-> getCode () = 4)
41. {
42. Echo "4:". $ e;
43. }
44. Else
45. {
46. Echo "0:". $ e;
47. }
48. }
49. Echo"
50.  
51. --------------------------------------------------------------------------------
52. ";
53. // Example of using different extended exception classes
54. Class A extends Exception {};
55. Class B extends Exception {};
56. Try
57. {
58. If ($ a = 1)
59. {
60. Throw new A ("I am A", 1 );
61. }
62. Elseif ($ a = 2)
63. {
64. Throw new B ("I am B", 2 );
65. }
66. Else
67. {
68. Throw new Exception ("Who am I? ", 0 );
69. }
70. }
71. Catch (A $ e)
72. {
73. Echo "1:". $ e;
74. }
75. Catch (B $ e)
76. {
77. Echo "2:". $ e;
78. }
79. Catch (Exception $ e)
80. {
81. Echo "0:". $ e;
82. }
83. ?>

The output is as follows:

The following is a reference clip:

0: exception 'exception' with message 'Who am I? 'In |

D: WebPHPWWWnewtest. php: 24 Stack trace: #0 {main}

----------------------------------------------------------------------------

0: exception 'exception' with message 'Who am I? 'In D: WebPHPWWWnewtest. php: 69 Stack trace: #0 {main}