Chapter 9 input/output stream 1-4

Code:

1. Package ch09;
3. Import java. Io. bufferedreader;
4. Import java. Io. bufferedwriter;
5. Import java. Io. chararrayreader;
6. Import java. Io. chararraywriter;
7. Import java. Io. file;
8. Import java. Io. fileinputstream;
9. Import java. Io. filenotfoundexception;
10. Import java. Io. filereader;
11. Import java. Io. filewriter;
12. Import java. Io. ioexception;
13. Import java. util. collections;
15. Class homeworkch09 {
16. Public homeworkch09 (){
17. System. Out. println ("Chapter 9 after-school exercise questions. ");
18. }
20. // 1. Write an application to read the content of a text file.
21. Public void key01 (){
22. File file = new file ("E:/workspaced/javahomework", "hello.txt"); // same directory as the current application
23. // System. Out. println (file. getpath ());
24. Byte B [] = "DD". getbytes ();
25. Try {
27. Fileinputstream FCM = new fileinputstream (File );
28. Int n = 0;
29. // Test garbled characters
30. String STR = NULL;
31. While (n = FCM. Read (B, 0, 2 ))! =-1) {// read two bytes to prevent garbled characters
32. STR = new string (B, 0, N );
33. System. Out. Print (STR );
34. }
35. } Catch (filenotfoundexception e) {// an exception cannot be found in the file.
36. E. printstacktrace ();
37. } Catch (ioexception e ){
38. E. printstacktrace ();
39. }
40. }
42. // 2. Write an application that saves 10 lines of text entered by the user from the keyboard to the file.
43. Public void key02 (){
44. Filewriter file = NULL;
45. Try {
46. File = new filewriter ("mydoc.txt ");
47. Bufferedwriter BW = new bufferedwriter (File );
48. For (INT I = 0; I <10; I ++ ){
49. Internal reader = new external (system. In );
50. Bw. Write (reader. nextline ());
51. Bw. Flush ();
52. }
53. File. Close ();
54. Bw. Close ();
55. } Catch (ioexception e ){
56. E. printstacktrace ();
57. }
58. }
60. // 3. Use the array audio stream to write Russian letters into the memory, and then read them from the memory.
61. /** The answer output contains 32 Russian letters and 33 letters. Although the answer and answer are two different letters, they are only different in the spoken language, when writing or printing, you can simply turn it into plain. */
62. Public void key03 (){
64. Int startposition = (INT) 'hangzhou'; // first letter in Russian
65. Int endposition = (INT) 'hangzhou'; // last Russian letter
66. System. Out. println ("Russian letters in total:" + (startposition-endposition ));
67. // For (INT I = 1040; I <1072; I ++ ){
68. // System. Out. Print (char) I );
69. //}
70. Int n =-1;
72. Chararraywriter out = new chararraywriter ();
73. For (INT I = startposition; I <= endposition; I ++ ){
74. Out. Write (I );
75. }
76. Chararrayreader in = new chararrayreader (Out. tochararray ());
77. Try {
78. While (n = in. Read ())! =-1 ){
79. If (N % 2 = 0 ){
80. System. Out. println ("/N ");
81. }
82. System. Out. printf ("/t position % d, character/'% C/'", N, (char) N );
83. }
84. } Catch (ioexception e ){
85. E. printstacktrace ();
86. }
87. }
89. // 4. Write an application, store the 10 integers entered by the user on the keyboard into the file, and read them in sequence.
90. Public void key04 () {// ==================== use a buffer stream ==============================
91. File file = new file ("key04.txt ");
92. Try {
93. Filewriter out = new filewriter (File );
94. Bufferedwriter out2 = new bufferedwriter (out );
95. Int I = 0;
96. While (I <2 ){
97. S = new partition (system. In );
98. String STR = S. nextline ();
99. Out2.write (STR );
100. Out2.newline (); // write a response
101. Out2.flush (); // refresh the buffer
102. I ++;
103. }
105. Filereader in = new filereader (File );
106. Bufferedreader in2 = new bufferedreader (in );
108. String integers = NULL;
109. While (integers = in2.readline ())! = NULL ){
110. System. Out. println (integers );
111. }
112. } Catch (filenotfoundexception e ){
113. E. printstacktrace ();
114. } Catch (ioexception e ){
115. E. printstacktrace ();
116. }
117. }
119. }
121. Public class ch09_1 {
123. Public static void main (string [] ARGs ){
124. Homeworkch09 HK = new homeworkch09 ();
125. // Test location
126. }
127. }