http断点续传简单实现（java)

/* $rJgBN  
**SiteFileFetch.java n5#QQk2  
*/ 7uf5w0]
  
package NetFox; 9fWR8iV  
import java.io.*; &fsk ESV0  
import java.net.*; wD/jN:  
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public class SiteFileFetch extends Thread { 9Wg;M#c2Y|  
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SiteInfoBean siteInfoBean = null; //文件信息Bean $3gM P+  
long[] nStartPos; //开始位置 "<Yxt"Z4  
long[] nEndPos; //结束位置 <g&.UW4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,g4T>7`&U%  
long nFileLength; //文件长度
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boolean bFirst = true; //是否第一次取文件 $KhD>4^jL  
boolean bStop = false; //停止标志 [E+J=L.l  
File tmpFile; //文件下载的临时信息 &-!$qUli  
DataOutputStream output; //输出到文件的输出流 l](!2a=[  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） e}n(mq  
public SiteFileFetch(SiteInfoBean bean) throws IOException mmG]|Cl@  
{ F8#MI G   
siteInfoBean = bean;  Vvp
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); I2-ue 63 ?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~'|^|*}~Dj  
if(tmpFile.exists ()) ysC
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{ 4l>U13~#  
bFirst = false; Z|fi$2k0!  
read_nPos(); ?2R!n"m-d  
} pNZ3vTs6  
else *
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{ !E|R3eX_  
nStartPos = new long[bean.getNSplitter()]; A'Z!l20_  
nEndPos = new long[bean.getNSplitter()]; k2fJ  
} gvPHB+#A  
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} 72
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public void run() |onLJY7)  
{ s Ytn'&$\  
//获得文件长度 4>2\{0r  
//分割文件 |`pBI0Sjo  
//实例FileSplitterFetch <WnIJum  
//启动FileSplitterFetch线程 #DARZhU)  
//等待子线程返回 m%UF{I,  
try{ ^6Zx-Mf\  
if(bFirst) wp'[AR
}  
{ lHPnAaue@  
nFileLength = getFileSize(); yE.st9m  
if(nFileLength == -1) nf[KD,f  
{ gI9nxy  
System.err.println("File Length is not known!"); 8k)*f+1o  
} ,1cpV|mAr  
else if(nFileLength == -2) s];0-65)  
{  deq5u>  
System.err.println("File is not access!"); 6)W8HX~+  
} wkx#WC  
else $at\aJ  
{ +t&+f7  
for(int i=0;i<nStartPos.length;i++) Z[l+{  
{ c}|}
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); .3jijc j  
} >o%X;U 3  
for(int i=0;i<nEndPos.length-1;i++) vbX.0f "n  
{ y+
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nEndPos = nStartPos[i+1]; 6 8fnh'I!  
} |eg8F$WU  
nEndPos[nEndPos.length-1] = nFileLength; xi
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} G$)tp^%]  
} [O}D^qp  
.:
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//启动子线程 6xY6EC  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; q&O9W?E8dG  
for(int i=0;i<nStartPos.length;i++) <%W&xk  
{ m:Rm(ga9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f:y:: z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $FDGHFM  
nStartPos,nEndPos,i); P #8+1iC1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R4'>5.M  
fileSplitterFetch.start(); ("{vbs$;  
} XD?]+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H|,d`@U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]&B/rSC  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [6 "5  
nEndPos = " + nFileLength); mey -Bn  
// fileSplitterFetch[nPos.length-1].start(); YXmy-o>  
1(*+_TvZ  
x^i97dZS^"  
//等待子线程结束 |/c-~|%  
//int count = 0; C-@M|K9A'  
//是否结束while循环 @[`]w
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boolean breakWhile = false; A|@d{g  
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while(!bStop) YHke^Ind
 
{ ux*G*QZ  
write_nPos(); *b!.9pK  
Utility.sleep(500); 7/fJQM  
breakWhile = true; T,Q7 YI  
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for(int i=0;i<nStartPos.length;i++) @3 +   
{ q4'
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if(!fileSplitterFetch.bDownOver) 7
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{ ^^24a_+2  
breakWhile = false; {zc*yV\  
break; 0F6@aQ\y3  
} E7.{SGH}  
} wr(*RI"  
if(breakWhile) O<mA+yk  
break; C OL"/3r  
+z#+}'mT%  
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//count++; l}T@Cgt  
//if(count>4) beT[7uVj_  
// siteStop(); :/Z1$xS  
} m(1ot M9  
{j<?+o5A  
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System.err.println("文件下载结束！"); u[4h|*'"|  
} [H9<JdUZ  
catch(Exception e){e.printStackTrace ();} V$iA3)7W%  
} >HzTaXCR[  
3j[<nBsn.  
sya!VF]`  
//获得文件长度 Yt_t>  
public long getFileSize() Lm.N {NV'  
{ ;*U&lT  
int nFileLength = -1; &|Rww\oJ  
try{ mq(K_  
URL url = new URL(siteInfoBean.getSSiteURL()); "jq6FT)O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Sht3\cJ8  
httpConnection.setRequestProperty("User-Agent","NetFox"); G=CP17&h6  
m(5LXHJnv  
MCIuP`sC|  
int responseCode=httpConnection.getResponseCode(); e5lJ)_o  
if(responseCode>=400) Jvj* z6/a  
{ :xO43z  
processErrorCode(responseCode); T :^OW5d  
return -2; //-2 represent access is error VP?Q$?a  
} U+(qfa5(  
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String sHeader; }s#4m  
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for(int i=1;;i++) nJ1<8 p  
{ F4~O-g.<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h CV(O2jL  
//Utility.log(in.readLine()); p_fsEY  
sHeader=httpConnection.getHeaderFieldKey(i); B4c;/W-  
if(sHeader!=null) f{\[+>  
{ 8{7'w|/;.{  
if(sHeader.equals("Content-Length")) ]/%CTD(O  
{ ;Yg/y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m1tc="j  
break;
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} DGz}d,ie  
} @00&J~D  
else j.V
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break; +K2HMf'  
} 63t'|9^5  
} ;L$l0(OO  
catch(IOException e){e.printStackTrace ();} WS1Y maV  
catch(Exception e){e.printStackTrace ();} :g-vy9vb  
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- s{&_]A~  
Utility.log(nFileLength); |y
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return nFileLength; MQy,[y7I  
} m (kKUv  
?8<R)hJa<  
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//保存下载信息（文件指针位置） =~dXP  
private void write_nPos() K8QEHc:  
{ (8~Hr?1B  
try{ 3#F"UG2,_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); y>r^ MQ  
output.writeInt(nStartPos.length); + eZn  
for(int i=0;i<nStartPos.length;i++) Gq?>Bi;`  
{ :0o]#7  
// output.writeLong(nPos); ^~bAixH^k  
output.writeLong(fileSplitterFetch.nStartPos); <){J|O  
output.writeLong(fileSplitterFetch.nEndPos); 92*"3)
  
} "9y0]~  
output.close();
"M %WV>  
} 7Fb!;W#X  
catch(IOException e){e.printStackTrace ();} E-?JHJloU  
catch(Exception e){e.printStackTrace ();} BG]|iHi  
} Xcg+ SOB  
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//读取保存的下载信息（文件指针位置） !\\1#:*_W  
private void read_nPos() |~Vq"6`  
{ G49`
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try{ !4$o*{9Lx:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); e\*N Lj_(  
int nCount = input.readInt(); S3c%</'  
nStartPos = new long[nCount]; E1qf N>0Z  
nEndPos = new long[nCount]; ~(^?M  
for(int i=0;i<nStartPos.length;i++) X}&Y(kOT  
{ gzyi'K<  
nStartPos = input.readLong(); >kDkvg1"  
nEndPos = input.readLong(); Cv]$w(k  
} sB'~=1m^  
input.close(); d! _8+~  
} Cg^1(dBd[9  
catch(IOException e){e.printStackTrace ();} dQNW1-s  
catch(Exception e){e.printStackTrace ();} XIp>PcU^  
} pJ@->V_  
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private void processErrorCode(int nErrorCode) [>:9
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{ 8Tp!b %2.  
System.err.println("Error Code : " + nErrorCode); }SS~uQ;8  
} KFM)*Icg\8  
"Y=4Y;5q  
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//停止文件下载 ;!H]&2`'(  
public void siteStop() r+i=P_p  
{ A$::|2~  
bStop = true; ;7m
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for(int i=0;i<nStartPos.length;i++) N6!9QIu~i  
fileSplitterFetch.splitterStop(); ^4a|gc  
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} r}#,@<  
} qu/b:P  
//负责部分文件的抓取 e:n3@T,
R  
**FileSplitterFetch.java U%tpNWB  
*/ @$o^(my  
package NetFox; XhJYsq]]J  
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import java.io.*; /)XN^Jwa;m  
import java.net.*; 2nB{oF-Z  
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public class FileSplitterFetch extends Thread { vu_ u\2d  
}h9f(ZyJn  
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String sURL; //File URL ">Y(0^^  
long nStartPos; //File Snippet Start Position U)qG]RI  
long nEndPos; //File Snippet End Position p9*Ak U&]  
int nThreadID; //Thread's ID Q^oB`)k  
boolean bDownOver = false; //Downing is over p+xjYU4^C  
boolean bStop = false; //Stop identical 7)l+hZ  
FileAccessI fileAccessI = null; //File Access interface `& ]H`KNa  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }r;#|=HR  
{ WCwM+D  
this.sURL = sURL; Uk0 0lPG.U  
this.nStartPos = nStart; ,V ) |A=ml  
this.nEndPos = nEnd; $Rf)iW;h  
nThreadID = id; B3@\Ua)  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #Dl=K<I  
} '/<f'R^  
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public void run() 4inMd![  
{ e!1am%aE  
while(nStartPos < nEndPos && !bStop) KqzQLu  
{ T7ICXpe@  
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try{ =(p]
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URL url = new URL(sURL); ?0'db  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )L$)qfQ~x  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7;Vqr$9)  
String sProperty = "bytes="+nStartPos+"-"; 80Z'1'u0  
httpConnection.setRequestProperty("RANGE",sProperty); pLsWy&G  
Utility.log(sProperty); pXoT@[}  
5>S)+p  
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InputStream input = httpConnection.getInputStream(); h0zv@,u  
//logResponseHead(httpConnection); &&`-A6`p  
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byte[] b = new byte[1024]; kZ<"hsh,Y'  
int nRead; v|;}}ol  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) fH?s~X]  
{  [?moS!  
nStartPos += fileAccessI.write(b,0,nRead); fwz-)?   
//if(nThreadID == 1) !)LVZfQ0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); eBg:[44V  
} e c4vX  
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Utility.log("Thread " + nThreadID + " is over!"); t4r%EP|Zt  
bDownOver = true; U$=#yg2 :  
//nPos = fileAccessI.write (b,0,nRead); Ec l/2  
} \CZD.2p#&  
catch(Exception e){e.printStackTrace ();} 
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} 'qiDh[ATa  
} Q<2`ek  
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//打印回应的头信息 )wfqGkr=m!  
public void logResponseHead(HttpURLConnection con) .dTXC'  
{ H{VJS Jc{  
for(int i=1;;i++) )]3_o!o
  
{ ,p9>/)l  
String header=con.getHeaderFieldKey(i); R}HNi(%"  
if(header!=null) C=<PYkt,L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); W&;,7T8@  
Utility.log(header+" : "+con.getHeaderField(header)); H.*aVb$  
else +VRM:&  
break; +`l)W`zX  
} 2HF_kYZ  
} Y3?)*kz%  
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L_Lhmtm}m  
public void splitterStop() L<[%tvV  
{ y5`$Aa4~  
bStop = true; 9;`E,w  
} <@J0 770  
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} Wr;9Mz&{  
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/* tu5T^"BqO  
**FileAccess.java 0^>b=a  
*//文件访问(定位，写) 4-JyK%m,0  
package NetFox; W9/HM!  
import java.io.*; !]t5(g_  
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public class FileAccessI implements Serializable{ agp7zw=N  
EdC/]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 tM3Q;8gB!  
RandomAccessFile oSavedFile; TWSx9ii!M:  
long nPos; JbLHW26pl  
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public FileAccessI() throws IOException }5]7lGR  
{ 9oTtH7%  
this("",0); /#g P#Z%  
} PHxNo)  
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public FileAccessI(String sName,long nPos) throws IOException w5* Z\t5  
{ 7,"y!\  
oSavedFile = new RandomAccessFile(sName,"rw"); lAJP X  
this.nPos = nPos; FG)(,?q  
oSavedFile.seek(nPos); e)*-<AGwC  
} Y4{/P1F  
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W=\4
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public synchronized int write(byte[] b,int nStart,int nLen) +D d!  
{ A&
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int n = -1; \%|%C  
try{ IH3Nk
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oSavedFile.write(b,nStart,nLen); BD?u|Fd,i:  
n = nLen; {wv
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} N<^)tR8+  
catch(IOException e) {iYrC m[_  
{ V-kx=M"k  
e.printStackTrace (); a7n`(}?Y  
}
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return n; bkFO4OZd  
} N^f_hL|:9  
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} *>E_lWW.  
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/* ([dJ'OPx$  
**SiteInfoBean.java G>,43S!<  
*/ gubw&W  
package NetFox; 
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public class SiteInfoBean { eL88lV]I  
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private String sSiteURL; //Site's URL ]DjnzClx  
private String sFilePath; //Saved File's Path Scfe6+\EW  
private String sFileName; //Saved File's Name </!GU*  
private int nSplitter; //Count of Splited Downloading File E?
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m{f+!  
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public SiteInfoBean() |J$Bj?  
{//nSplitter的缺省值为5 ?D;7ut$~  
//default value of nSplitter is 5 ^J'O8G$  
this("","","",5); %#TAz7  
} fLZ mQO  
u4h.\ul8%  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Y2[ik<  
{ c!N#nt_<  
sSiteURL= sURL; -f["1-A  
sFilePath = sPath; X}g"_wN,g>  
sFileName = sName; z&y
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this.nSplitter = nSpiltter; Mh]4K"cs  
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} Hi nJ}MF  
2=
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public String getSSiteURL() :+f6:3  
{ +]p/.-Uw  
return sSiteURL; cCs@[D#O1  
} )M*Sg?L  
%xA-j]%?ep  
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public void setSSiteURL(String value) RQU-]qQ8BM  
{ !uP8powO  
sSiteURL = value; 8>`8p0I$+  
} Oj '^Ww m  
$B`ETI9g-N  
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public String getSFilePath() ;?C`Jagx  
{ |lN=q44I  
return sFilePath; L@.Trso  
} 1dOB|  
!X`cNd)0Xo  
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public void setSFilePath(String value) f.0HIc  
{ is=x6G*r  
sFilePath = value; T?CQgVR  
} jT`u!CwdT  
m -0}Pe9L  
9<.8mW^68  
public String getSFileName() `4wy *!]  
{ -Gjz+cRns  
return sFileName; 4kR;K!@k  
} Q)\[wYMt  
2V*;=cv~z  
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public void setSFileName(String value)
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{ 
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sFileName = value; 6=96^o*  
} !-t"}^)  
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? M.'YB2  
public int getNSplitter() >7z(?nQYT^  
{ n[\L6}  
return nSplitter; 9'p*7o  
} %~P3t=r  
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/Mj|Px%  
public void setNSplitter(int nCount) jQ8 T  
{ bI8')a  
nSplitter = nCount; #mD_<@@  
} ?rziKT5OOC  
} }{mS"  
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/* !wC( ]Y  
**Utility.java /T2 v`Li  
*/ qcge#S>  
package NetFox; >8&fFq  
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public class Utility { PP]7_h^2  
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public Utility() i-.AD4  
{ 2b Fr8FUt-  
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} >_$_fB  
=E-o@#BS  
//线程睡眠 Oz
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public static void sleep(int nSecond) uo;m  
{ iiWpmE<,  
try{ G-,0mo  
Thread.sleep(nSecond); OLV3.~T  
} >CwI(vXn  
catch(Exception e) Eo6qC?5<  
{ $LcMG,8%_  
e.printStackTrace (); b1G6'~U-  
} '&$zgK9T?  
} X&Sah}0V&  
4vNH"72P  
//日志 wFjQ1
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public static void log(String sMsg) e [6F }."c  
{ Ggy?5N7P  
System.err.println(sMsg); N^AlhR^  
} Spn)M79  
/1uGsE+[  
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public static void log(int sMsg) P@%L.y B  
{ jy_4W!4a  
System.err.println(sMsg); C0/G1\  
} ='@k>Ka+  
} rq1zvuUx  
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DyA1zwp}  
/* kq([c r  
**TestMethod.java \tY7Ga%c  
*/ L\!Oj5  
package NetFox; `u_k?)lK  

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87m`K Str7  
public class TestMethod { Wtp=1  
FlY"OU*  
2fNNdxdbT  
public TestMethod() "xn,'`a  
{ ///xx/weblogic60b2_win.exe S~&
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try{ n xR\tBv  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); R<%{I)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^:,wk7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E,cQ9}/  
fileFetch.start(); yU"#2 *C  
} P% 8U  
catch(Exception e){e.printStackTrace ();} 3,#v0#  
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} Mm1
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public static void main(String[] args) N/<c;"o  
{ ="PFCxi  
new TestMethod(); XqwP<5Z  
} .F[5{XV  
} d/awQXKe7  
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