Go语言视频零基础入门到精通

javalearner

启动５个线程的运行情况：
C:java>java TestMethod
1091
Thread 0 , nStartPos = 0, nEndPos = 218
Thread 1 , nStartPos = 218, nEndPos = 436
Thread 2 , nStartPos = 436, nEndPos = 654
Thread 3 , nStartPos = 654, nEndPos = 872
Thread 4 , nStartPos = 872, nEndPos = 1091
bytes=0-
bytes=218-
bytes=436-
bytes=654-
bytes=872-
Thread 0 is over!
Thread 1 is over!
Thread 4 is over!
Thread 2 is over!
Thread 3 is over!
文件下载结束！  
   
  
主要代码：（其它请下载）

1. /*
   
2. **SiteFileFetch.java
   
3. */
   
4. import java.io.*;
   
5. import java.net.*;
   
6. 
   
7. 
   
8. public class SiteFileFetch extends Thread {
   
9. 
   
10. 
    
11.   SiteInfoBean siteInfoBean = null; //文件信息Bean
    
12.   long[] nStartPos; //开始位置
    
13.   long[] nEndPos; //结束位置
    
14.   FileSplitterFetch[] fileSplitterFetch; //子线程对象
    
15.   long nFileLength; //文件长度
    
16.   boolean bFirst = true; //是否第一次取文件
    
17.   boolean bStop = false; //停止标志
    
18.   File tmpFile; //文件下载的临时信息
    
19.   DataOutputStream output; //输出到文件的输出流
    
20. 
    
21.   //负责整个文件的抓取，控制内部线程（FileSplitterFetch类）
    
22.   public SiteFileFetch(SiteInfoBean bean) throws IOException{
    
23.      siteInfoBean = bean;
    
24.      //tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
    
25.      tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
    
26.      if(tmpFile.exists ()){
    
27.            bFirst = false;
    
28.            read_nPos();//读取已下载的文件信息，断点续传
    
29.      }else{
    
30.         nStartPos = new long[bean.getNSplitter()];
    
31.         nEndPos = new long[bean.getNSplitter()];
    
32.       }
    
33. 
    
34. }
    
35. 
    
36. 
    
37. public void run(){
    
38.    //获得文件长度
    
39.    //分割文件
    
40.    //实例FileSplitterFetch
    
41.   //启动FileSplitterFetch线程
    
42.   //等待子线程返回
    
43. try{
    
44.     if(bFirst){
    
45.        nFileLength = getFileSize();
    
46.        if(nFileLength == -1){
    
47.          System.err.println("File Length is not known!");
    
48.        }else if(nFileLength == -2){
    
49.         System.err.println("File is not access!");
    
50.        }else{
    
51.          for(int i=0;i< nStartPos.length;i++){
    
52.              nStartPos[i] = (long)(i*(nFileLength/nStartPos.length));
    
53.           }
    
54.          for(int i=0;i< nEndPos.length-1;i++){
    
55.           nEndPos[i] = nStartPos[i+1];
    
56.          }
    
57.          nEndPos[nEndPos.length-1] = nFileLength;
    
58.         }
    
59.      }
    
60. 
    
61. 
    
62.     //启动子线程
    
63.      fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
    
64.      for(int i=0;i< nStartPos.length;i++){
    
65.         fileSplitterFetch[i] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
66.          siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), nStartPos[i],nEndPos[i],i);
    
67.         Utility.log("Thread " + i + " , nStartPos = " + nStartPos[i] + ", nEndPos = " + nEndPos[i]);
    
68.          fileSplitterFetch[i].start();
    
69.       }
    
70.     // fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
71.    siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
    
72.     // Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",nEndPos = " + nFileLength);
    
73.     // fileSplitterFetch[nPos.length-1].start();
    
74. 
    
75. 
    
76.    //等待子线程结束
    
77.    //int count = 0;
    
78.    //是否结束while循环
    
79.    boolean breakWhile = false;
    
80. 
    
81. 
    
82.    while(!bStop){
    
83.      write_nPos();//记录每个线程的下载情况
    
84.      Utility.sleep(500);
    
85.      breakWhile = true;
    
86. 
    
87. 
    
88.     for(int i=0;i< nStartPos.length;i++){
    
89.        if(!fileSplitterFetch[i].bDownOver){
    
90.           breakWhile = false;
    
91.           break;
    
92.       }
    
93.     }
    
94.     if(breakWhile)
    
95.        break;
    
96.    }
    
97. 
    
98.     System.err.println("文件下载结束！");
    
99. }catch(Exception e){
    
100.     e.printStackTrace ();
     
101. }
     
102. }
     
103. 
     
104. 
     
105. //获得文件长度
     
106. public long getFileSize(){
     
107.    // System.out.println("Ok");
     
108.     int nFileLength = -1;
     
109.     try{
     
110.      URL url = new URL(siteInfoBean.getSSiteURL());
     
111.      HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
     
112.      httpConnection.setRequestProperty("User-Agent","NetFox");
     
113.      int responseCode=httpConnection.getResponseCode();
     
114.      if(responseCode>=400){
     
115.          processErrorCode(responseCode);
     
116.          return -2; //-2 represent access is error
     
117.       }
     
118. 
     
119. 
     
120.      String sHeader;
     
121. 
     
122. 
     
123.      for(int i=1;;i++){
     
124.        //DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
     
125.        //Utility.log(in.readLine());
     
126.        sHeader=httpConnection.getHeaderFieldKey(i);
     
127.        if(sHeader!=null){
     
128.           if(sHeader.equals("Content-Length")){
     
129.                  nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));
     
130.                  //System.out.println("OK"+nFileLength);
     
131.                  break;
     
132.            }
     
133.         }else
     
134.            break;
     
135.        }
     
136.    }catch(IOException e){e.printStackTrace ();
     
137.    }catch(Exception e){e.printStackTrace ();}
     
138. 
     
139. 
     
140.     Utility.log(nFileLength);
     
141. 
     
142. 
     
143.     return nFileLength;
     
144. }
     
145. 
     
146. 
     
147. //保存下载信息（文件指针位置）
     
148. private void write_nPos(){
     
149.   try{
     
150.      output = new DataOutputStream(new FileOutputStream(tmpFile));
     
151.      output.writeInt(nStartPos.length);
     
152.      for(int i=0;i< nStartPos.length;i++){
     
153. //output.writeLong(nPos[i]);
     
154.    output.writeLong(fileSplitterFetch[i].nStartPos);
     
155.     output.writeLong(fileSplitterFetch[i].nEndPos);
     
156.       }
     
157.       output.close();
     
158. }catch(IOException e){e.printStackTrace ();}
     
159. catch(Exception e){e.printStackTrace ();}
     
160. }
     
161. 
     
162. 
     
163. //读取保存的下载信息（文件指针位置）
     
164. private void read_nPos(){
     
165. try{
     
166.     DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));
     
167.     int nCount = input.readInt();
     
168.     nStartPos = new long[nCount];
     
169.     nEndPos = new long[nCount];
     
170.     for(int i=0;i< nStartPos.length;i++){
     
171.       nStartPos[i] = input.readLong();
     
172.       nEndPos[i] = input.readLong();
     
173.     }
     
174.     input.close();
     
175.   }catch(IOException e){e.printStackTrace ();}
     
176.     catch(Exception e){e.printStackTrace ();}
     
177. }
     
178. 
     
179. 
     
180. private void processErrorCode(int nErrorCode)
     
181. {
     
182.    System.err.println("Error Code : " + nErrorCode);
     
183. }
     
184. 
     
185. 
     
186. //停止文件下载
     
187. public void siteStop(){
     
188.    bStop = true;
     
189.    for(int i=0;i< nStartPos.length;i++)
     
190.       fileSplitterFetch[i].splitterStop();
     
191. 
     
192. 
     
193.   }
     
194. }
     

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源码下载：http://file.javaxxz.com/2014/10/30/000015203.zip