Android 下载文件及写入SD卡,实例代码
1. <?xml version="1.0" encoding="utf-8"?>
2. <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
3. "vertical"
4. "fill_parent"
5. "fill_parent"
6. >
7. <Button
8. "@+id/downloadTxt"
9. "fill_parent"
10. "wrap_content"
11. "下载文本文件"
12. />
13.
14. <Button
15. "@+id/downloadMp3"
16. "fill_parent"
17. "wrap_content"
18. "下载MP3文件"
19. />
20. </LinearLayout>
1. <?xml version="1.0" encoding="utf-8"?>
2. <manifest xmlns:android="http://schemas.android.com/apk/res/android"
3. "com.learning.example"
4. "1"
5. "1.0">
6. "@drawable/icon" android:label="@string/app_name">
7. ".Download"
8. "@string/app_name">
9. <intent-filter>
10. "android.intent.action.MAIN"
11. "android.intent.category.LAUNCHER"
12. </intent-filter>
13. </activity>
14.
15. </application>
16. "8"
17.
18. <!-- 访问网络和操作SD卡 加入的两个权限配置-->
19. <uses-permission android:name="android.permission.INTERNET"/>
20. <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
21. </manifest>
1. package com.learning.example.util;
2.
3. import java.io.BufferedReader;
4. import java.io.File;
5. import java.io.IOException;
6. import java.io.InputStream;
7. import java.io.InputStreamReader;
8. import java.net.HttpURLConnection;
9. import java.net.MalformedURLException;
10. import java.net.URL;
11.
12. public class HttpDownloader {
13.
14. private URL url = null;
15.
16. /**
17. * 根据URL下载文件,前提是这个文件当中的内容是文本,函数的返回值就是文本当中的内容
18. 1.创建一个URL对象
19. 2.通过URL对象,创建一个HttpURLConnection对象
20. 3.得到InputStream
21. 4.从InputStream当中读取数据
22. * @param urlStr
23. * @return
24. */
25. public String download(String urlStr){
26. StringBuffer sb = new StringBuffer();
27. String line = null;
28. BufferedReader buffer = null;
29. try {
30. url = new URL(urlStr);
31. HttpURLConnection urlConn = (HttpURLConnection)url.openConnection();
32. buffer = new BufferedReader(new InputStreamReader(urlConn.getInputStream()));
33. while( (line = buffer.readLine()) != null){
34. sb.append(line);
35. }
36.
37. }
38. catch (Exception e) {
39. e.printStackTrace();
40. }
41. finally{
42. try {
43. buffer.close();
44. } catch (IOException e) {
45. e.printStackTrace();
46. }
47. }
48. return sb.toString();
49. }
50.
51. /**
52. *
53. * @param urlStr
54. * @param path
55. * @param fileName
56. * @return
57. 1:文件下载出错
58. 0:文件下载成功
59. 1:文件已经存在
60. */
61. public int downFile(String urlStr, String path, String fileName){
62. InputStream inputStream = null;
63. try {
64. FileUtils fileUtils = new FileUtils();
65.
66. if(fileUtils.isFileExist(path + fileName)){
67. 1;
68. } else {
69. inputStream = getInputStreamFromURL(urlStr);
70. File resultFile = fileUtils.write2SDFromInput(path, fileName, inputStream);
71. if(resultFile == null){
72. 1;
73. }
74. }
75. }
76. catch (Exception e) {
77. e.printStackTrace();
78. 1;
79. }
80. finally{
81. try {
82. inputStream.close();
83. } catch (IOException e) {
84. e.printStackTrace();
85. }
86. }
87. 0;
88. }
89.
90. /**
91. * 根据URL得到输入流
92. * @param urlStr
93. * @return
94. */
95. public InputStream getInputStreamFromURL(String urlStr) {
96. HttpURLConnection urlConn = null;
97. InputStream inputStream = null;
98. try {
99. url = new URL(urlStr);
100. urlConn = (HttpURLConnection)url.openConnection();
101. inputStream = urlConn.getInputStream();
102.
103. } catch (MalformedURLException e) {
104. e.printStackTrace();
105. } catch (IOException e) {
106. e.printStackTrace();
107. }
108.
109. return inputStream;
110. }
111. }
1. package com.learning.example.util;
2.
3. import java.io.File;
4. import java.io.FileOutputStream;
5. import java.io.IOException;
6. import java.io.InputStream;
7. import java.io.OutputStream;
8.
9. import android.os.Environment;
10.
11. public class FileUtils {
12. private String SDPATH;
13.
14. 4 * 1024;
15.
16. public String getSDPATH(){
17. return SDPATH;
18. }
19.
20. public FileUtils(){
21. //得到当前外部存储设备的目录( /SDCARD )
22. "/";
23. }
24.
25. /**
26. * 在SD卡上创建文件
27. * @param fileName
28. * @return
29. * @throws IOException
30. */
31. public File createSDFile(String fileName) throws IOException{
32. File file = new File(SDPATH + fileName);
33. file.createNewFile();
34. return file;
35. }
36.
37. /**
38. * 在SD卡上创建目录
39. * @param dirName
40. * @return
41. */
42. public File createSDDir(String dirName){
43. File dir = new File(SDPATH + dirName);
44. dir.mkdir();
45. return dir;
46. }
47.
48. /**
49. * 判断SD卡上的文件夹是否存在
50. * @param fileName
51. * @return
52. */
53. public boolean isFileExist(String fileName){
54. File file = new File(SDPATH + fileName);
55. return file.exists();
56. }
57.
58. /**
59. * 将一个InputStream里面的数据写入到SD卡中
60. * @param path
61. * @param fileName
62. * @param input
63. * @return
64. */
65. public File write2SDFromInput(String path,String fileName,InputStream input){
66. File file = null;
67. OutputStream output = null;
68. try {
69. createSDDir(path);
70. file = createSDFile(path + fileName);
71. output = new FileOutputStream(file);
72. byte[] buffer = new byte[FILESIZE];
73. 1){
74. output.write(buffer);
75. }
76. output.flush();
77. }
78. catch (Exception e) {
79. e.printStackTrace();
80. }
81. finally{
82. try {
83. output.close();
84. } catch (IOException e) {
85. e.printStackTrace();
86. }
87. }
88. return file;
89. }
90.
91. }
1. package com.learning.example;
2.
3. import com.learning.example.util.HttpDownloader;
4.
5. import android.app.Activity;
6. import android.os.Bundle;
7. import android.view.View;
8. import android.view.View.OnClickListener;
9. import android.widget.Button;
10.
11. public class Download extends Activity {
12. private Button downlaodTxtButton ;
13. private Button downlaodMP3Button ;
14.
15. @Override
16. public void onCreate(Bundle savedInstanceState) {
17. super.onCreate(savedInstanceState);
18. setContentView(R.layout.main);
19. downlaodTxtButton = (Button)findViewById(R.id.downloadTxt);
20. downlaodTxtButton.setOnClickListener(new DownloadTxtListener());
21.
22. downlaodMP3Button = (Button)findViewById(R.id.downloadMp3);
23. downlaodMP3Button.setOnClickListener(new DownloadMP3Listener());
24. }
25.
26. class DownloadTxtListener implements OnClickListener{
27.
28. @Override
29. public void onClick(View v) {
30. HttpDownloader downloader = new HttpDownloader();
31. "http://172.16.11.9:8080/test/1.lrc");
32. System.out.println(lrc);
33. }
34.
35. }
36.
37. class DownloadMP3Listener implements OnClickListener{
38.
39. @Override
40. public void onClick(View v) {
41. HttpDownloader downloader = new HttpDownloader();
42. "http://172.16.11.9:8080/test/1.mp3", "voa/", "1.map3");
43. System.out.println(result);
44. }
45.
46. }
47. }Notice:访问网络和操作SD卡 记得加入的两个权限配置
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
