1、视图
1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 2 xmlns:tools="http://schemas.android.com/tools" 3 android:layout_width="match_parent" 4 android:layout_height="match_parent" 5 android:orientation="vertical" 6 tools:context=".MainActivity" > 7 8 <EditText 9 android:id="@+id/et_path" 10 android:layout_width="fill_parent" 11 android:layout_height="wrap_content" 12 android:text="http://202.96.2.126/android/360.exe" 13 android:hint="请输入地址" /> 14 15 <ProgressBar 16 android:id="@+id/pb" 17 style="?android:attr/progressBarStyleHorizontal" 18 android:layout_width="fill_parent" 19 android:layout_height="wrap_content" />" 20 21 <Button 22 android:onClick="downLoad" 23 android:layout_width="wrap_content" 24 android:layout_height="wrap_content" 25 android:text="下载" 26 /> 27 28 29 30 </LinearLayout>
2、权限
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
3、多线程下载代码
1 package com.example.mymutildownload;
2
3 import java.io.File;
4 import java.io.FileInputStream;
5 import java.io.InputStream;
6 import java.io.RandomAccessFile;
7 import java.net.HttpURLConnection;
8 import java.net.URL;
9
10 import android.os.Bundle;
11 import android.app.Activity;
12 import android.text.TextUtils;
13 import android.view.Menu;
14 import android.view.View;
15 import android.widget.EditText;
16 import android.widget.ProgressBar;
17 import android.widget.Toast;
18
19 public class MainActivity extends Activity {
20
21 private EditText et_path;
22 private ProgressBar pb;
23 private static int threadCount=3;
24 private static int liveThread = 3;
25 private static int currentLength = 0;
26 @Override
27 protected void onCreate(Bundle savedInstanceState) {
28 super.onCreate(savedInstanceState);
29 setContentView(R.layout.activity_main);
30 et_path = (EditText)findViewById(R.id.et_path);
31 pb = (ProgressBar)findViewById(R.id.pb);
32 }
33
34
35 public void downLoad(View view){
36 final String path = et_path.getText().toString().trim();
37 if(TextUtils.isEmpty(path)){
38 Toast.makeText(this, "路径不能为空", 0).show();
39 return;
40 }
41
42 new Thread(){
43 public void run(){
44 try {
45 URL url = new URL(path);
46 HttpURLConnection conn = (HttpURLConnection) url.openConnection();
47 conn.setReadTimeout(5000);
48 conn.setRequestMethod("GET");
49 int code = conn.getResponseCode();
50 if(code == 200){
51 int length = conn.getContentLength();
52 System.out.println("文件的长度:" + length);
53 //生成一个文件
54 RandomAccessFile raf = new RandomAccessFile("/sdcard/360.exe", "rwd");
55 raf.setLength(length);
56 raf.close();
57
58 //设置进度条的长度
59 pb.setMax(length);
60 //文件大小
61 int blockSize = length / threadCount;
62 for(int threadId=1; threadId <= threadCount; threadId++){
63 //下载的起始位置
64 int startIndex = (threadId - 1) * blockSize;
65 //结束位置
66 int endIndex = threadId * blockSize - 1;
67 if(threadId == threadCount){
68 endIndex = length;
69 }
70 System.out.println("线程" + threadId + "的起始位置为:" + startIndex + " 结束位置为:" + endIndex);
71 //启动线程
72 new DownloadThread(threadId, startIndex, endIndex, path).start();
73 }
74 }
75 } catch (Exception e) {
76 // TODO Auto-generated catch block
77 e.printStackTrace();
78 System.out.println("链接失败");
79 }
80 };
81 }.start();
82 }
83
84
85 public class DownloadThread extends Thread{
86 private int threadId;
87 private int startIndex;
88 private int endIndex;
89 private String path;
90 public DownloadThread(int threadId, int startIndex, int endIndex,
91 String path) {
92 this.threadId = threadId;
93 this.startIndex = startIndex;
94 this.endIndex = endIndex;
95 this.path = path;
96 }
97 @Override
98 public void run(){
99 try {
100 //判断文件是否存在
101 File tmpFile = new File("/sdcard/" + threadId + ".txt");
102 if(tmpFile.exists()){
103 FileInputStream fis = new FileInputStream(tmpFile);
104 byte[] buf = new byte[1024];
105 fis.read(buf);
106 String downedLen = new String(buf).trim();
107 startIndex = Integer.parseInt(downedLen);
108 fis.close();
109 }
110
111 System.out.println("线程" + threadId + "aaaaaaaaaaaa的起始位置为:" + startIndex + " 结束位置为:" + endIndex);
112 URL url = new URL(path);
113 HttpURLConnection conn = (HttpURLConnection) url.openConnection();
114 conn.setReadTimeout(5000);
115 conn.setRequestMethod("GET");
116 conn.setRequestProperty("Range", "bytes=" + startIndex + "-" + endIndex);
117 int code = conn.getResponseCode();
118 System.out.println("返回码是:" + code);
119 InputStream is = conn.getInputStream();
120 RandomAccessFile raf = new RandomAccessFile("/sdcard/360.exe", "rwd");
121 raf.seek(startIndex);
122 int len=0;
123 byte[] buffer = new byte[1024];
124 //位置计算
125 int pos = startIndex;
126 while((len = is.read(buffer)) != -1){
127 RandomAccessFile info = new RandomAccessFile("/sdcard/" + threadId + ".txt", "rw");
128 raf.write(buffer, 0, len);
129 pos = pos + len;
130 //System.out.println("线程" + threadId + "已经下载的" + pos);
131 //设置进度条
132 synchronized(MainActivity.this){
133 currentLength = currentLength + len;
134 pb.setProgress(currentLength);
135 }
136
137 info.write((pos + "").getBytes());
138 info.close();
139 }
140 is.close();
141 raf.close();
142 System.out.println("线程" + threadId + "下载完毕!");
143 } catch (Exception e) {
144 // TODO Auto-generated catch block
145 e.printStackTrace();
146 }finally{
147 liveThread--;
148 if(liveThread == 0){
149 for(int i=1; i <= threadCount; i++){
150 File delFile = new File("/sdcard/" + i + ".txt");
151 delFile.delete();
152 }
153 System.out.println("删除了文件");
154 }
155 }
156
157 }
158 }
159 @Override
160 public boolean onCreateOptionsMenu(Menu menu) {
161 // Inflate the menu; this adds items to the action bar if it is present.
162 getMenuInflater().inflate(R.menu.main, menu);
163 return true;
164 }
165
166 }
时间： 2024-09-28 08:00:03