Multi-Threaded Download server-side picture resources

Service side situation is: Http://192.168.1.105:8080:/web/sky.jpg hit enter, in the browser display image resources >>>>>>> service-side code omitted ....

Down_activity.xml (button is to submit a Web request to download the picture, TextView is the interface prompt when the download is completed)

<?xml version= "1.0" encoding= "Utf-8"? ><linearlayout xmlns:android= "http://schemas.android.com/apk/res/ Android "    android:layout_width=" match_parent "    android:layout_height=" match_parent "    android:o rientation= "vertical" >    <textview        android:id= "@+id/textview" android:layout_width= "Wrap_        Content "        android:layout_height=" wrap_content "/>    <button        android:id=" @+id/button "        Android : layout_width= "wrap_content"        android:layout_height= "wrap_content"        android:text= "Download"/></ Linearlayout>

Downloadactivity

Package Com.lw.http01;import Android.app.activity;import Android.os.bundle;import android.os.handler;import Android.view.view;import Android.widget.button;import Android.widget.textview;public class DownLoadActivity extends Activity {private TextView textview;private Button button;private int count = 0;private Handler Handler = new Handler () {p ublic void Handlemessage (Android.os.Message msg) {int result = Msg.what;count + = result;if (count = = 3) {//Complete download Update UI interface can be T Extview.settext ("Download Success");};}; @Overrideprotected void OnCreate (Bundle savedinstancestate) {super.oncreate (savedinstancestate); Setcontentview ( r.layout.down_activity) TextView = (TextView) Findviewbyid (r.id.textview); button = (button) Findviewbyid (R.id.button ); Button.setonclicklistener (new View.onclicklistener () {@Overridepublic void OnClick (View v) {/** * Gets the network picture in the child thread */new Thread () {public void run () {DownLoad load = new DownLoad (handler); Load.downloadfile ("http://192.168.1.105:8080:/web/ Sky.jpg ");};}. Start ();}});}}

DownLoad

Package Com.lw.http01;import Java.io.file;import Java.io.inputstream;import java.io.randomaccessfile;import Java.net.httpurlconnection;import Java.net.url;import Java.util.concurrent.executor;import Java.util.concurrent.executors;import Android.os.environment;import Android.os.handler;import android.os.Message; public class DownLoad {/** * Creates a thread pool of 3 threads */private Executor threadPool = Executors.newfixedthreadpool (3); static class downl Oadrunnable implements Runnable {/** * Defines the parameters passed over */private string url;private string filename;private long start;private l  Ong end;private Handler handler;public downloadrunnable (string url, String fileName, long Start,long end, Handler Handler) {super (); This.url = Url;this.filename = Filename;this.start = Start;this.end = End;this.handler = handler;} @Overridepublic void Run () {try {//Create URL address, and set the value URL httpurl = new URL (URL); HttpURLConnection conn = (httpurlconnection) httpurl.openconnection (); conn.setreadtimeout (5000); Conn.setrequestmethod ("GET");//HTTP protocol. PleaseSpecifies the length of the stream information Conn.setrequestproperty ("Range", "bytes=" + Start + "-" + end);//Locate write information to the specified file folder randomaccessfile access = new Ra Ndomaccessfile (FileName), "RWD");//To Snap to start point--position the file record pointer to the POS location. Access.seek (start);//Get input path. Get files from server InputStream in = Conn.getinputstream (); byte[] B = new byte[1024 * 4];int len = 0;while (len = In.read (b))! =- 1) {//Output access.write (b, 0, Len);} if (access! = NULL) {Access.close ();} if (in = null) {In.close ();} After each thread completes the download, the message is sent with a msg = new message (); message.what = 1;handler.sendmessage (message);} The catch (Exception e) {}}}/** * definition handler is due to the need for handler to send messages in downloadrunnable (each thread completes the download send message. Update main interface) */private Handler handler;public DownLoad (Handler Handler) {this.handler = Handler;} public void downLoadFile (String url) {try {/** * * creates URL address information. and set the number of parameters */url Httpurl = new URL (URL); HttpURLConnection conn = (httpurlconnection) httpurl.openconnection (); conn.setreadtimeout (5000); Conn.setrequestmethod ("get");//Get the overall size of the network resource int count = Conn.getcontentlength ();//Download each downloadthe size int block = count/3;//Gets the suffix name of the network resource string filename = getFile (URL);//Gets the folder root Folder file Parent = Environment.getexternalsto  Ragedirectory ();//Gets the true absolute path of the file DownLoadFile = new (parent, fileName);/** * 11 Overall Size/3 Blcok for 3 + 2 first thread 0-2 second thread 3-5 Third thread 6-10 */for (int i = 0; i < 3; i++) {Long start = i * block;long end = (i + 1) * BLOCK-1;IF (i = = 2) {end = Cou NT;} /** * Delivery start, end is due to Setrequestproperty because the protocol requires these 2 parameters * URL is because each thread download requires URL address information hander is sending a message. Update UI interface */downloadrunnable runnable = new Downloadrunnable (Url,downloadfile.getabsolutepath (), start, end, Handler); Threadpool.execute (runnable);}} catch (Exception e) {}}//Gets the file's suffix name by URL, public string getFile (string url) {return url.substring (Url.lastindexof ("/") + 1) ;}}

Multi-Threaded Download server-side picture resources