Android入門：實現一個File存儲的輔助類

Android入門：File文件存儲 教程鏈接：http://www.linuxidc.com/Linux/2012-07/66002.htm

1. package com.xiazdong.file.util;
3. import java.io.ByteArrayOutputStream;
4. import java.io.File;
5. import java.io.FileInputStream;
6. import java.io.FileOutputStream;
7. import java.io.IOException;
8. import java.io.InputStream;
10. import android.content.Context;
11. import android.os.Environment;
13. public class FileUtil {
14. /**
15. * 保存文本到內存
16. * @param context
17. * @param filename
18. * @param content
19. * @param mode
20. * @throws Exception
21. */
22. public static void saveTextInMemory(Context context,String filename,String content,int mode) throws Exception{
23. try{
24. FileOutputStream out = context.openFileOutput(filename, mode);
25. out.write(content.getBytes("UTF-8"));
26. out.close();
27. }
28. catch(Exception e){
29. throw new Exception();
30. }
31. }
32. /**
33. * 保存文件到sdcard
34. * @param filename
35. * @param content
36. * @throws Exception
37. */
38. public static void saveTextInSdcard(String filename,String content) throws Exception{
39. try{
40. File f = new File(Environment.getExternalStorageDirectory(),filename);
41. FileOutputStream out = new FileOutputStream(f);
42. out.write(content.getBytes("UTF-8"));
43. out.close();
44. }
45. catch(Exception e){
46. throw new Exception();
47. }
48. }
49. /**
50. * 從內存讀取文件
51. * @param filename
52. * @return
53. * @throws Exception
54. */
55. public static String loadTextFromSdcard(String filename) throws Exception{
56. try{
57. File f = new File(Environment.getExternalStorageDirectory(),filename);
58. FileInputStream in = new FileInputStream(f);
59. byte[]data = read2byte(in);
60. return new String(data,"UTF-8");
61. }
62. catch(Exception e){
63. throw new Exception();
64. }
65. }
66. /**
67. * 從sdcard讀取文件
68. * @param context
69. * @param filename
70. * @return
71. * @throws Exception
72. */
73. public static String loadTextFromMemory(Context context,String filename) throws Exception{
74. try{
75. FileInputStream in = context.openFileInput(filename);
76. byte[]data = read2byte(in);
77. return new String(data,"UTF-8");
78. }
79. catch(Exception e){
80. throw new Exception();
81. }
82. }
83. private static byte[] read2byte(InputStream in) throws IOException {
84. byte[] data;
85. ByteArrayOutputStream bout = new ByteArrayOutputStream();
86. byte[]buf = new byte[1024];
87. int len = 0;
88. while((len = in.read(buf))!=-1){
89. bout.write(buf, 0, len);
90. }
91. data = bout.toByteArray();
92. return data;
93. }
94. }

測試代碼：

1. FileUtil.saveTextInSdcard("1.txt","hello"); //將"hello"保存到/mnt/sdcard/1.txt中
2. String content = FileUtil.loadTextFromSdcard("1.txt"); //讀取/mnt/sdcard/1.txt內容
3. FileUtil.saveTextInMemory(MainActivity.this,"1.txt","hello", Context.MODE_PRIVATE); //將hello保存到/data/data/package/files/1.txt中
4. String content = FileUtil.loadTextFromMemory(MainActivity.this, "1.txt"); //讀取/data/data/package/files/1.txt內容