Android下载文本文件和mp3文件
布局文件main.xml
main.xml
1 <?xml version="1.0" encoding="utf-8"?>
2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
3 android:layout_width="fill_parent"
4 android:layout_height="fill_parent"
5 android:orientation="vertical" >
6
7 <Button
8 android:id="@+id/downloadTxt"
9 android:layout_width="fill_parent"
10 android:layout_height="wrap_content"
11 android:text="Download text"/>
12 <Button
13 android:id="@+id/downloadMp3"
14 android:layout_width="fill_parent"
15 android:layout_height="wrap_content"
16 android:text="Download MP3"/>
17 </LinearLayout>
Activity文件DownloadFileToSDKCardActivity.java
DownloadFileToSDKCardActivity.java
1 package paul.Activity;
2
3 import paul.utils.HttpDownloadUtil;
4 import android.app.Activity;
5 import android.os.Bundle;
6 import android.view.View;
7 import android.view.View.OnClickListener;
8 import android.widget.Button;
9
10 //创建一个HttpURLConnection对象
11 //HttpURLConnection urlConn=(HttpURLConnection)url.openConnection();
12 //获取一个InputStream对象
13 //InputStream is=urlConn.getInputStream();
14 //访问网络权限
15 //android.permission.INTERNET
16 //得到当前设备SD卡的目录
17 //Environment.getExternalStorageDirectory()
18 //访问SD卡的权限
19 //android.permission.WEITE_EXTERNAL_STORAGE
20 public class DownloadFileToSDKCardActivity extends Activity {
21 /** Called when the activity is first created. */
22 HttpDownloadUtil httpDownloadUtil;
23 private Button downloadTxt;
24 private Button downloadMp3;
25 public DownloadFileToSDKCardActivity(){
26 httpDownloadUtil=new HttpDownloadUtil();
27 }
28 @Override
29 public void onCreate(Bundle savedInstanceState) {
30 super.onCreate(savedInstanceState);
31 setContentView(R.layout.main);
32 downloadTxt=(Button) this.findViewById(R.id.downloadTxt);
33 downloadTxt.setOnClickListener(new DownloadTxt());
34 downloadMp3=(Button) this.findViewById(R.id.downloadMp3);
35 downloadMp3.setOnClickListener(new DownloadMp3());
36 }
37
38
39 class DownloadTxt implements OnClickListener{
40
41 @Override
42 public void onClick(View arg0) {
43 String url="http://www.baidu.com";
44 System.out.println(httpDownloadUtil.downFile(url));
45 }
46
47 }
48
49 class DownloadMp3 implements OnClickListener{
50
51 @Override
52 public void onClick(View arg0) {
53 String url="http://media.ringring.vn/ringtone/realtone/0/0/161/165346.mp3";
54 //int index=url.lastIndexOf("/");
55 //String fileName=url.substring(index+1);
56 int result=httpDownloadUtil.downFile(url, "music", "aa.mp3");
57 System.out.println(result);
58 }
59
60 }
61 }
文件下载类HttpDownloadUtil.java
HttpDownloadUtil.java
1 package paul.utils;
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 HttpDownloadUtil {
13
14 /**
15 * 根据URL下载文件，前提是这个文件当中的内容是文本，函数返回值是文件当中的文本内容
16 * @param urlstr
17 * @return
18 */
19 public String downFile(String urlstr){
20 StringBuffer sb=new StringBuffer();
21 BufferedReader buffer=null;
22 URL url=null;
23 String line=null;
24 try {
25 //创建一个URL对象
26 url=new URL(urlstr);
27 //根据URL对象创建一个Http连接
28 HttpURLConnection urlConn=(HttpURLConnection) url.openConnection();
29 //使用IO读取下载的文件数据
30 buffer=new BufferedReader(new InputStreamReader(urlConn.getInputStream()));
31 while((line=buffer.readLine())!=null){
32 sb.append(line);
33 }
34 } catch (MalformedURLException e) {
35 // TODO Auto-generated catch block
36 e.printStackTrace();
37 } catch (IOException e) {
38 // TODO Auto-generated catch block
39 e.printStackTrace();
40 }finally{
41 try {
42 buffer.close();
43 } catch (IOException e) {
44 e.printStackTrace();
45 }
46 }
47 return sb.toString();
48 }
49
50 /**
51 * 该函数返回整形 -1：代表下载文件错误0 ：下载文件成功1：文件已经存在
52 * @param urlstr
53 * @param path
54 * @param fileName
55 * @return
56 */
57 public int downFile(String urlstr,String path,String fileName){
58 InputStream inputStream=null;
59 FileUtils fileUtils=new FileUtils();
60
61 if(fileUtils.isFileExist(path+fileName)){
62 return 1;
63 }else{
64 inputStream=getInputStreamFormUrl(urlstr);
65 File resultFile=fileUtils.writeToSDfromInput(path, fileName, inputStream);
66 if(resultFile==null){
67 return -1;
68 }
69 }
70 return 0;
71 }
72
73 /**
74 * 根据URL得到输入流
75 * @param urlstr
76 * @return
77 */
78 public InputStream getInputStreamFormUrl(String urlstr){
79 InputStream inputStream=null;
80 try {
81 URL url=new URL(urlstr);
82 HttpURLConnection urlConn=(HttpURLConnection) url.openConnection();
83 inputStream=urlConn.getInputStream();
84 } catch (MalformedURLException e) {
85 e.printStackTrace();
86 } catch (IOException e) {
87 e.printStackTrace();
88 }
89 return inputStream;
90 }
91 }
保存文件到SD卡通用工具类FileUtils.java
FileUtils.java
1 package paul.utils;
2
3 import java.io.File;
4 import java.io.FileNotFoundException;
5 import java.io.FileOutputStream;
6 import java.io.IOException;
7 import java.io.InputStream;
8 import java.io.OutputStream;
9
10 import android.os.Environment;
11
12 public class FileUtils {
13 private String SDPath;
14
15 public FileUtils(){
16 //得到当前外部存储设备的目录
17 SDPath=Environment.getExternalStorageDirectory().getAbsolutePath()+"/";
18 }
19
20 /**
21 * 在SD卡上创建文件
22 * @param fileName
23 * @return
24 */
25 public File createSDFile(String fileName){
26 File file=new File(SDPath+fileName);
27 try {
28 file.createNewFile();
29 } catch (IOException e) {
30 e.printStackTrace();
31 }
32 return file;
33 }
34
35 /**
36 * 在SD卡上创建目录
37 * @param dirName
38 * @return
39 */
40 public File createSDDir(String dirName){
41 File file=new File(SDPath+dirName);
42 file.mkdir();
43 return file;
44 }
45
46 /**
47 * 判断SD卡上文件是否存在
48 * @param fileName
49 * @return
50 */
51 public boolean isFileExist(String fileName){
52 File file=new File(SDPath+fileName);
53 return file.exists();
54 }
55 /**
56 * 将一个inputStream里面的数据写到SD卡中
57 * @param path
58 * @param fileName
59 * @param inputStream
60 * @return
61 */
62 public File writeToSDfromInput(String path,String fileName,InputStream inputStream){
63 //createSDDir(path);
64 File file=createSDFile(path+fileName);
65 OutputStream outStream=null;
66 try {
67 outStream=new FileOutputStream(file);
68 byte[] buffer=new byte[4*1024];
69 while(inputStream.read(buffer)!=-1){
70 outStream.write(buffer);
71 }
72 outStream.flush();
73 } catch (FileNotFoundException e) {
74 e.printStackTrace();
75 } catch (IOException e) {
76 e.printStackTrace();
77 }finally{
78 try {
79 outStream.close();
80 } catch (IOException e) {
81 e.printStackTrace();
82 }
83 }
84 return file;
85 }
86 }
AndroidManifest.xml
AndroidManifest.xml
1 <?xml version="1.0" encoding="utf-8"?>
2 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
3 package="paul.Activity"
4 android:versionCode="1"
5 android:versionName="1.0" >
6
7 <uses-sdk android:minSdkVersion="10" />
8 <uses-permission android:name="android.permission.INTERNET" />
9 <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
10 <application
11 android:icon="@drawable/ic_launcher"
12 android:label="@string/app_name" >
13 <activity
14 android:name=".DownloadFileToSDKCardActivity"
15 android:label="@string/app_name" >
16 <intent-filter>
17 <action android:name="android.intent.action.MAIN" />
18
19 <category android:name="android.intent.category.LAUNCHER" />
20 </intent-filter>
21 </activity>
22 </application>
23 </manifest>
