http断点续传简单实现（java)

/* |:H[Y"$1;  
**SiteFileFetch.java lX5(KUN
 
*/ 0JNG\ARC  
package NetFox; >xP
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import java.io.*; GVEjB;  
import java.net.*; uE5kL{Fv  
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public class SiteFileFetch extends Thread { uv_*E`pN~  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 6x[gg !;85  
long[] nStartPos; //开始位置 y'4=  
long[] nEndPos; //结束位置 ?'h@!F%R'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 p(Qm\g<  
long nFileLength; //文件长度 2]>s@?[  
boolean bFirst = true; //是否第一次取文件 M}%0=VCY7  
boolean bStop = false; //停止标志 FirmzB Il5  
File tmpFile; //文件下载的临时信息 CiPD+I  
DataOutputStream output; //输出到文件的输出流 X
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） "2=v?,'t  
public SiteFileFetch(SiteInfoBean bean) throws IOException .`,YUr$.  
{ 1Z`<HW"  
siteInfoBean = bean; MR+ndB<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =cRJtn  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @p
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if(tmpFile.exists ()) M>T#MDK\(  
{ q"]-CGAa  
bFirst = false; @~a52'\  
read_nPos(); c]xpp;%]  
} |0-5-.  
else ?,s{M^sj^  
{ gQ/zk3?k  
nStartPos = new long[bean.getNSplitter()]; o
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nEndPos = new long[bean.getNSplitter()]; dks0  
} (dO4ww@O  
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} ulVHsWg  
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public void run() 8vaqj/  
{ @rVmr{UE  
//获得文件长度 lYy
0   
//分割文件 Grw_SVa^  
//实例FileSplitterFetch KE(kR>OB]  
//启动FileSplitterFetch线程 |/r@z[t  
//等待子线程返回 #UGbSOoCtn  
try{ ?mF-zA'4]  
if(bFirst) y8,es$  
{ `D GO~RMp9  
nFileLength = getFileSize(); I#9K/

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if(nFileLength == -1) orL7y&w(v:  
{ Uvz9x"0[u  
System.err.println("File Length is not known!"); *W i(%  
} &=s{ +0  
else if(nFileLength == -2) 9`vse>,-hg  
{ Y4b"(ZhM_  
System.err.println("File is not access!"); X|.X4fs  
} 9N u;0  
else XvdK;  
{ UB(8N7_/  
for(int i=0;i<nStartPos.length;i++) Zi|'lHr  
{ 5a_K|(~3I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <Ojf&C^Z  
} ,rTR |>Z  
for(int i=0;i<nEndPos.length-1;i++) i2swots  
{ .>H7i`1D`  
nEndPos = nStartPos[i+1]; [9$>N  
} KL -8Aj~  
nEndPos[nEndPos.length-1] = nFileLength; QMkLAZ  
} =P2T
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} >r{,$)H0  
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g:OVAA  
//启动子线程 h{>8W0W*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2"%d!"  
for(int i=0;i<nStartPos.length;i++) @3b0hi4  
{ #<l;YT8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y+X%qT
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !5p01]7  
nStartPos,nEndPos,i); G =lC[i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ==|//:: \  
fileSplitterFetch.start(); *UEo&B2+  
} )%UO@4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5)EnOT"'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); QvqX3FU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Vwl`A3Y  
nEndPos = " + nFileLength); bC"#.e  
// fileSplitterFetch[nPos.length-1].start(); u QCQ$  
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$L;7SY?  
//等待子线程结束 IWKQU/l!  
//int count = 0; 9I.="b=J)  
//是否结束while循环 ]k>S0  
boolean breakWhile = false; [?]s((A~B  
_L&C4 <e'  
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while(!bStop) Rrk3EL  
{ -S9$C*t  
write_nPos(); xNl_Q8Z?R^  
Utility.sleep(500); UJlKw `4  
breakWhile = true; %hOe `2#$  
6kYn5:BhIi  
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for(int i=0;i<nStartPos.length;i++) `ZNzDr  
{ -CxaOZG  
if(!fileSplitterFetch.bDownOver) )<jj O  
{ Ue~M.LZb  
breakWhile = false; }JvyjE  
break; ?2DYz"/')  
} <BT}Tv9  
} #O`nQ  
if(breakWhile) ~FDJKGK  
break; P>jlFm  
+ZXk0sP_<  
VxaJ[s3PQ&  
//count++; .pG_j]  
//if(count>4) u9}=g%TV  
// siteStop(); oGXT,38*  
} s6!aGZ  
3X%>xUI  
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System.err.println("文件下载结束！"); CCQ<.iCU  
} I?5#Q0,b  
catch(Exception e){e.printStackTrace ();} X[|-F3o  
} eX$u  
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m!w(Q+*j  
//获得文件长度 :'a |cjq  
public long getFileSize() -*+7-9A I  
{ mWCY%o@  
int nFileLength = -1; /ey}#SHm,  
try{ 8 w^i  
URL url = new URL(siteInfoBean.getSSiteURL()); \*a7DuVw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @k~Xem%<  
httpConnection.setRequestProperty("User-Agent","NetFox");  :\gdQG  
;h3c+7u1  
&P,8)YA  
int responseCode=httpConnection.getResponseCode(); wVV'9pw}  
if(responseCode>=400) ANi}q9SC  
{ mI9~\k&9  
processErrorCode(responseCode); M>8#is(pV  
return -2; //-2 represent access is error #t po@pJsE  
} VbJGyjx  
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String sHeader; c?j/H$  
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for(int i=1;;i++) sDw&U?gUv  
{ 1kvBQ1+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); O-5H7Kd-  
//Utility.log(in.readLine()); ~S#Le  
sHeader=httpConnection.getHeaderFieldKey(i); )Q&:$]  
if(sHeader!=null) l>H#\MR  
{ Z[Uz~W6M]  
if(sHeader.equals("Content-Length")) 0ir]  
{ ^JJ*pT:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ftu4 V*lD  
break; >t3%-Kc  
} 0x[v)k9"0  
} Rw=gg>\  
else fg^$F9
@  
break; ~Wf&$p<|  
} VuPa'2  
} iO>2#p8$NR  
catch(IOException e){e.printStackTrace ();} +{4ziqYj  
catch(Exception e){e.printStackTrace ();} $5s?m\!jZz  
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>  
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Utility.log(nFileLength); o
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return nFileLength; (Lp<T!"  
} ENr\+{{%  
'%l<33*  
i4JqU\((]  
//保存下载信息（文件指针位置） <TC\Nb$
~  
private void write_nPos() IBo)fE\O  
{ ~\
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try{ x?y)a9&Hm  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6"/cz~h  
output.writeInt(nStartPos.length); n2Q~fx<6%  
for(int i=0;i<nStartPos.length;i++) CcG{+-=H)  
{ "+~La{POc  
// output.writeLong(nPos); 71Q-_Hi  
output.writeLong(fileSplitterFetch.nStartPos); DUFfk6#X}  
output.writeLong(fileSplitterFetch.nEndPos); {OXKXRCa  
} M]v
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output.close(); .m9s+D]fI  
} L$=6R3GI  
catch(IOException e){e.printStackTrace ();} +.! F]0ju  
catch(Exception e){e.printStackTrace ();} xi %u)p  
} 8rx?mX,}  
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//读取保存的下载信息（文件指针位置） WA\ P`'lg  
private void read_nPos() wi|'pKG  
{ |$f.Qs~?  
try{ 96fbMP+7R  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6F(;=iY8  
int nCount = input.readInt(); ?suxoP%  
nStartPos = new long[nCount]; /5b,&  
nEndPos = new long[nCount]; :*4b,P  
for(int i=0;i<nStartPos.length;i++) om@GH0
o+  
{ Z@4BTA  
nStartPos = input.readLong(); 'avzESe~'  
nEndPos = input.readLong(); S%uwQ!=O8  
} *9Ej fs7L  
input.close(); :7
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} Bvk 8b  
catch(IOException e){e.printStackTrace ();} s{#rCc)  
catch(Exception e){e.printStackTrace ();} P+tRxpz  
} +*Y/+.4WE$  
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4! ]28[2B6  
private void processErrorCode(int nErrorCode) ixm-wZI  
{ (,*e\o  
System.err.println("Error Code : " + nErrorCode); 7:awUoV8f  
} j>Ce06G  
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,  
//停止文件下载 [Q9#44@{S;  
public void siteStop() Cak`}J 2  
{ U.g7'`Z<  
bStop = true; !~#zH0#  
for(int i=0;i<nStartPos.length;i++) 2_k2t ?   
fileSplitterFetch.splitterStop(); lR3`4bHA  
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} {"k}C2K'r  
} sl?> X)}  
//负责部分文件的抓取 b9`vYnLk  
**FileSplitterFetch.java v/gxQy+l  
*/ eLPWoQXt  
package NetFox; 90<z*j$EK  
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import java.io.*; lrrNyaFn  
import java.net.*; 3msb"|DG  
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public class FileSplitterFetch extends Thread { <vS3[(  
c"F3[mrff  
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String sURL; //File URL m/TjXA8_  
long nStartPos; //File Snippet Start Position e x"E50  
long nEndPos; //File Snippet End Position L{PH8Xl_  
int nThreadID; //Thread's ID IP<]a5  
boolean bDownOver = false; //Downing is over >(T)9
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boolean bStop = false; //Stop identical ?D[9-K4Vn  
FileAccessI fileAccessI = null; //File Access interface SWwL.-+E]  
9vX~gh{]~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException A:Y ([  
{ XM?>#^nC?u  
this.sURL = sURL; P?WS=w*O0  
this.nStartPos = nStart; .t53+<A  
this.nEndPos = nEnd; -(~OzRfYi  
nThreadID = id; %)'# d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 y(81| c#  
} b~oQhU??"  

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public void run() 0o-.m  
{ u_31Db<  
while(nStartPos < nEndPos && !bStop) oJ4OVfknD  
{ y@GqAN'DK[  
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}o}  
try{ qK=uSLo\+  
URL url = new URL(sURL); nev@ykP6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o,(]w kF  
httpConnection.setRequestProperty("User-Agent","NetFox"); cl,\N\  
String sProperty = "bytes="+nStartPos+"-"; +q<G%PwbV  
httpConnection.setRequestProperty("RANGE",sProperty); E]@$,)nC  
Utility.log(sProperty); RV@'$`Q  
,76xa%k(U|  
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InputStream input = httpConnection.getInputStream(); }Zuk}Og9+  
//logResponseHead(httpConnection); {~*^jS']5  
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byte[] b = new byte[1024]; |!Ryl}Oi  
int nRead; A  [c1E[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) `PoFKtVXM  
{ Gn?NY}.S  
nStartPos += fileAccessI.write(b,0,nRead); rm}%C(C{J  
//if(nThreadID == 1) T5<851rH  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'GyO  
} u$M,&Om  
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Utility.log("Thread " + nThreadID + " is over!"); v~.nP} E^  
bDownOver = true; qp##>c31X  
//nPos = fileAccessI.write (b,0,nRead); #S4lRVt5  
} sV']p#HK0  
catch(Exception e){e.printStackTrace ();} HP,sNiw  
} IoAG!cS  
} /8Wfs5N  
I,8f{T!O@"  
6<hE]B)  
//打印回应的头信息 5 *R{N ~>  
public void logResponseHead(HttpURLConnection con) 'zo
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{ Z~S%|{&Br  
for(int i=1;;i++)  WPu-P  
{ yw@kh^L  
String header=con.getHeaderFieldKey(i);
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if(header!=null) aTWC
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ea,L04K  
Utility.log(header+" : "+con.getHeaderField(header)); -xVp}RLT  
else -Z(='A
 
break; P$7i>(?(  
} y3+iADo.p  
} L^E#"f  
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public void splitterStop() m8ApiGG  
{ 1fOH$33  
bStop = true; -s6k't  
} 7B@1[  
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} w\}@+w3b~  
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/*
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**FileAccess.java iwVsq_[]L  
*//文件访问(定位，写) FL|\D  
package NetFox; MW|*Z{6*  
import java.io.*; BB9+d"Sq  

ud grZ/w]  
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public class FileAccessI implements Serializable{ @,^c?v  
@{q:179w^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 cF V[k'F  
RandomAccessFile oSavedFile; +Y! P VMF  
long nPos; V] 0T P#  
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public FileAccessI() throws IOException 'c/S$_r
 
{
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this("",0); U_KCN09  
} p}e1!q;N  
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2L(\-]%f  
public FileAccessI(String sName,long nPos) throws IOException 7.y35y  
{ mDdL7I  
oSavedFile = new RandomAccessFile(sName,"rw"); LX8A@Yct  
this.nPos = nPos; 259R5X<V  
oSavedFile.seek(nPos); }.k*4Vw#Wt  
} 1@:BUE;jZ  
Ys@OgdS@:  
Q)[DSM  
public synchronized int write(byte[] b,int nStart,int nLen) qokCVI-\  
{ ]tx/t^&/\u  
int n = -1; YAP,#a  
try{ HD_
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oSavedFile.write(b,nStart,nLen); : *8t,f~s^  
n = nLen; J?%ecCN  
} e.VQ!)>  
catch(IOException e) B{tROuN<  
{ f`K[oCfu  
e.printStackTrace (); 5HC5   
} wLa8&E[  
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return n; 3C gmZ7[  
} ty\F~]Oo  
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} <~teD[1k"  
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/* JUCp#[q  
**SiteInfoBean.java ^xX1G_{  
*/ N;` jz(r  
package NetFox; U ATF}x  
N`J]k B7  
gp<XTLJ@>  
public class SiteInfoBean { p#0L@!,  
('z:XW96  
cd._q2  
private String sSiteURL; //Site's URL D k<NlH zp  
private String sFilePath; //Saved File's Path q:MSV{k  
private String sFileName; //Saved File's Name k+@,m\tE  
private int nSplitter; //Count of Splited Downloading File 8J)Kn4jq  
ZJ8"5RW  
}eAV8LU  
public SiteInfoBean() ER,!`C]  
{//nSplitter的缺省值为5 1|dXbyUd  
//default value of nSplitter is 5 Oy_%U*  
this("","","",5); | Di7,$c  
} y>>)Yo&|  
*cP(3n3]R  
: "^/?Sd  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B|K^:LUk9  
{ MxDqp;  
sSiteURL= sURL; ]@!3os,CNF  
sFilePath = sPath; l:+$Ks  
sFileName = sName; <Rfx`mn  
this.nSplitter = nSpiltter; @TJ2 |_s6]  
8?N![D\@  
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} K=1prv2  
s`en8%  
]E$bK  
public String getSSiteURL() dUL*~%2I  
{ FQ>y2n=<d  
return sSiteURL; 9]vy#a#  
} ^'p!#\T;H  
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M#k$[w}=  
public void setSSiteURL(String value) xW|8-q  
{ 4\E1M[6  
sSiteURL = value; u'T?e
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} 4_
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/?NfU.+K  
RiZ)#0  
public String getSFilePath() 22/"
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{ c_T+T
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return sFilePath; DQ@M?~1hp  
} EXsVZg"#  
'cqY-64CJZ  
SLz;5%CPV  
public void setSFilePath(String value) &2nICAN[  
{ L[^.pO  
sFilePath = value; y@(EGfI  
} /r8sL)D+  
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"R\D:Olb#  
public String getSFileName() 'p[*2J"K4  
{ <v!jS=T  
return sFileName; 3^iVDbAW{  
} &b'{3o_KN  
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s"5
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public void setSFileName(String value) 9iV9q]($0  
{ gZBb/<  
sFileName = value; 2sj: &][R  
} mU]pK5  
nErr&{C  
5me#/NqLHY  
public int getNSplitter() >sZ_I?YDs  
{ p=V1M-  
return nSplitter; 1vYa&!  
} N cp   
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m%nRHT0KAf  
public void setNSplitter(int nCount) D!8v$(#hR  
{ Uz=ol.E  
nSplitter = nCount; 22*~CIh~x  
} xiV!\Z}  
} 2UIZ<#|D>s  
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\]g51U!'  
/* "
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**Utility.java p,tkVedR  
*/ \E'z+0  
package NetFox; 9 e|[9  
] &SmeTe  
?Yx2q_KZk  
public class Utility { !DUOi4I  
3a&HW JBSx  
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public Utility() RXo6y(^  
{ hu>wcOt  
#ro$$I;  
4];>
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} 5LZs_%#  
P@Fx6  
//线程睡眠 QX42^]({;c  
public static void sleep(int nSecond) x=-(p}0o;<  
{ DXFDs=u  
try{ r?w>x`  
Thread.sleep(nSecond);
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} lbGPy'h<rt  
catch(Exception e) :9e4(7~ona  
{ ("YWJJ'H  
e.printStackTrace (); 1<cx!=w'  
} }=JSd@`_  
} A H=%6oT2  
ArScJ\/Nwv  
//日志 -zWNQp$  
public static void log(String sMsg) $$SJLV
  
{ C$$Zwgy  
System.err.println(sMsg); RR|X4h0.  
} VrWQ]L  
QpA$='  
=A
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public static void log(int sMsg) 8kC
$Z)  
{ Q`{Vs:8X  
System.err.println(sMsg); [e_<UF@A*  
} ?B@3A)
a  
} Gm &jlN  
=*{7G*tS  
C+>mehDC_G  
/* H0jbG;  
**TestMethod.java 8C[eHC*r  
*/ hL&7D@  
package NetFox; JpZ_cb`<E'  
}{kn/m/  
:S}ZF$ $j%  
public class TestMethod { C,%Dp0  
zqURnsJ  
).0p\.W~  
public TestMethod() K7C!ZXw~  
{ ///xx/weblogic60b2_win.exe K4o']{:U  
try{ LK!sk5/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (pHJEY  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0d+b<J,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _ nz^+  
fileFetch.start(); neE Zw#(Z  
} X]n`YF7  
catch(Exception e){e.printStackTrace ();} }gFa9M<  
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} @' %XdH  
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public static void main(String[] args) ,7 m33Pv*  
{ _\8E/4zh  
new TestMethod(); [mNum3e  
} xA<-'8ST  
} kM@e_YtpY  
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