http断点续传简单实现（java)

/* k1VT /u  
**SiteFileFetch.java 9}z0J  
*/ z"*/mP2  
package NetFox; r!,}Z=cGe  
import java.io.*; ]tY ^0a  
import java.net.*; xG;-bJu  
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public class SiteFileFetch extends Thread { :W@#) 1
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SiteInfoBean siteInfoBean = null; //文件信息Bean f-nz{U  
long[] nStartPos; //开始位置 )/t?!T.[  
long[] nEndPos; //结束位置 uytE^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 R-^96fFBy  
long nFileLength; //文件长度 9M"].~iNE  
boolean bFirst = true; //是否第一次取文件 ~n}k\s~|4  
boolean bStop = false; //停止标志 I5h[%T  
File tmpFile; //文件下载的临时信息 NAPX_B,6  
DataOutputStream output; //输出到文件的输出流 2S' {!A  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） KR"M/#  
public SiteFileFetch(SiteInfoBean bean) throws IOException oq*N_mP0  
{ BPr^D0P  
siteInfoBean = bean; kF>o.uSV  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (LHp%LaZ\;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); DS|KkTy3  
if(tmpFile.exists ()) Mc!Xf[  
{ Su 5>$  
bFirst = false; fqu}Le  
read_nPos(); /k"`7`!  
} +/D>|loRC  
else Bvt@X   
{ &F}"Z(B<wK  
nStartPos = new long[bean.getNSplitter()]; %6--}bY^  
nEndPos = new long[bean.getNSplitter()]; <W]g2>9o9  
} OCy0
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} !`bio cA  
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*._|
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public void run() ^s.V;R  
{ #yI.nzA*  
//获得文件长度 #.[AK_S5&  
//分割文件 ASPy  
//实例FileSplitterFetch 5PcJZi^.l
 
//启动FileSplitterFetch线程 >yJ9U,Y  
//等待子线程返回 Q%aU42?_1  
try{ E+C5 h ;p&  
if(bFirst) `"@X.}\  
{ {YUIMd!Y  
nFileLength = getFileSize(); 6dAEM;$_Z  
if(nFileLength == -1) 1}ZKc=Pfu  
{ ob_I]~^I?|  
System.err.println("File Length is not known!"); |#l=  
} VOsqJJ3  
else if(nFileLength == -2) )6~1 ^tD  
{ K\XyZ  
System.err.println("File is not access!"); V#ev-\k}@  
} P'MY[&|mM'  
else !se0F.K  
{ i*R,QN)  
for(int i=0;i<nStartPos.length;i++) 1+`l
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{ 4lKVY<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); C6_@\&OA  
} "!K'A7.^  
for(int i=0;i<nEndPos.length-1;i++) 5BR5X\f0  
{ ZDL']*)'  
nEndPos = nStartPos[i+1]; :ug4g6;#H0  
} 27ckdyQx  
nEndPos[nEndPos.length-1] = nFileLength; hC_Vts[v/  
} }B7K@Wu#  
} x( mE<UQN  
M\b")Tu{0  
&/.hx(#d  
//启动子线程 0:KE@=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; eK/?%t  
for(int i=0;i<nStartPos.length;i++) 4;`Bj:.  
{ HmK*bZ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TgU**JN)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), m\/(w_/?  
nStartPos,nEndPos,i); ;jK#[*y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U-wLt(Y<  
fileSplitterFetch.start(); b{DiM098  
} 1G~S|,8p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /RLq>#:h**  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); o  A*G  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +5v}q.:+  
nEndPos = " + nFileLength); 04!(okubyp  
// fileSplitterFetch[nPos.length-1].start(); {+zJI-XN/  
mxwdugr`  
6`\]derSon  
//等待子线程结束 ngulcv  
//int count = 0; ,(G%
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//是否结束while循环 >95TvJ  
boolean breakWhile = false; 2}}?'PwwT  
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4"\yf  
while(!bStop) T)7TyE|"2g  
{ !/K8xD$  
write_nPos(); u%O-;>J  
Utility.sleep(500); ~c{:DM  
breakWhile = true; 2=PBxDs;  
:&'{mJW*{t  
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for(int i=0;i<nStartPos.length;i++) VS?@y/\In  
{ j&6
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if(!fileSplitterFetch.bDownOver) ]Gc3Ea;4  
{ ?3sT"r_d@  
breakWhile = false; )He#K+[}^4  
break; |c-LSs'\  
} kR.wOJ7'  
} )Du-_Z  
if(breakWhile) b`cYpcs  
break; `NwdbKX  
?BCyJ  
71B3a  
//count++; 5IMSNGS  
//if(count>4) >e5zrgV  
// siteStop(); v@ONo?)  
} o6j"OZcv  
^[h2%c$  
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System.err.println("文件下载结束！"); MQcE6)  
} >L2*CV3p  
catch(Exception e){e.printStackTrace ();} coQ[@vu  
} [j6~}zu@  
V*B0lI7`B  
` DCU>bt&R  
//获得文件长度 {ctwo X[;  
public long getFileSize() bLG]Wa  
{ sV0Z  
int nFileLength = -1; l^ 4OC
 
try{ ;?9A(q_Z  
URL url = new URL(siteInfoBean.getSSiteURL()); H$!-f>Rxa  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +!&$SNLh(  
httpConnection.setRequestProperty("User-Agent","NetFox"); q G;-o)h  
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int responseCode=httpConnection.getResponseCode(); `ENP=kL(+  
if(responseCode>=400) j)D-BK&+  
{ UC9{m252  
processErrorCode(responseCode); cIw eBDl  
return -2; //-2 represent access is error `!c,y~r[  
} l=Wd,$\  
<*@~n- R$  
(-(*XNC  
String sHeader; nTZ> |R)  
(DJvi6\H  
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for(int i=1;;i++) #4y,a_)  
{ {;RF  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L~MpY{!3  
//Utility.log(in.readLine()); G*\sdBW!k  
sHeader=httpConnection.getHeaderFieldKey(i); jKt-~:  
if(sHeader!=null) &telCg:  
{ ltEF:{mLe#  
if(sHeader.equals("Content-Length")) R#0{Wg0O)  
{ RWE~&w G}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]V<"(?,K  
break; ]bfqcmh<  
} w`#fH  
} gB+ G'I  
else PRpE$`WK  
break; IxP^i{/1?  
} 2Guvze_bU  
} :Y.e[@!1x  
catch(IOException e){e.printStackTrace ();} ]31$KBC  
catch(Exception e){e.printStackTrace ();} + zDc  
nO_!:6o".  
!QTPWA  
Utility.log(nFileLength); ,I39&;Iq  
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return nFileLength; R9=K(pOT  
} uo 4xnzc  
:)LC gIQo  
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//保存下载信息（文件指针位置） IozNjII$:.  
private void write_nPos() JjDS"hK#  
{ BvI 0v:  
try{ ~>w:;M=sV8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ".M:`BoW4  
output.writeInt(nStartPos.length); /#IH-2N  
for(int i=0;i<nStartPos.length;i++) \4@a  
{ -R74/GBg  
// output.writeLong(nPos); ]Da4.s*mW  
output.writeLong(fileSplitterFetch.nStartPos); >Qk97we'9  
output.writeLong(fileSplitterFetch.nEndPos); a|z1
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} S| "TP\o  
output.close(); 7?"9J`*  
} }6@%((9E2  
catch(IOException e){e.printStackTrace ();} +Z$a1Y@  
catch(Exception e){e.printStackTrace ();} `OLB';D  
} [U']kt  
} Ab_o#Zy  
|DGCdB|`G  
//读取保存的下载信息（文件指针位置） EGEMZCdk2  
private void read_nPos() ]]3Q*bq4  
{ Y)v
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try{ g6`.qyVfz'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _]_LF[  
int nCount = input.readInt(); qAbd xd[  
nStartPos = new long[nCount]; 5 Af?Yxv  
nEndPos = new long[nCount]; klo^K9!  
for(int i=0;i<nStartPos.length;i++) 4NI'(#l  
{ tB!|p6  
nStartPos = input.readLong(); BMF3XcH~G  
nEndPos = input.readLong(); JQr36U  
} $ JuLAqq  
input.close(); fW[_+r]  
} W -3w7^  
catch(IOException e){e.printStackTrace ();} /:^tc/5U]  
catch(Exception e){e.printStackTrace ();} I>!|3ElT  
} 6XZN>#  
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8@Q"YA3d+  
private void processErrorCode(int nErrorCode) `}ZL'\G  
{ '2j~WUEmg  
System.err.println("Error Code : " + nErrorCode); Zq9>VqGe  
} )y5iH){!  
J (=4  
m/cx|b3hqv  
//停止文件下载 :> x:(K  
public void siteStop() Scf.4~H 0  
{ x9TuweG  
bStop = true; aTi0bQW{  
for(int i=0;i<nStartPos.length;i++) ^75pV%<%  
fileSplitterFetch.splitterStop(); @i\7k(9:A  
0;'j!`l9  
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} A<]&JbIt  
} +~@7" |d  
//负责部分文件的抓取 xMLrLXy  
**FileSplitterFetch.java yFIl^Ck%  
*/ 7Z9.z4\  
package NetFox; O#A8t<f|M  
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import java.io.*; -i2D#i'  
import java.net.*; oM-b96  
#vnefIcBf  
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public class FileSplitterFetch extends Thread { wbn^R'  
9T?~$XlX  
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String sURL; //File URL /vMQF+  
long nStartPos; //File Snippet Start Position oD Q9.t  
long nEndPos; //File Snippet End Position X^u4%O['  
int nThreadID; //Thread's ID VZAuUw+M  
boolean bDownOver = false; //Downing is over cu)@P0I  
boolean bStop = false; //Stop identical MYKs??]Y1  
FileAccessI fileAccessI = null; //File Access interface AEiWL.*.  
)zo#1$C-  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8') .ohD  
{ nD^{Q[E6=  
this.sURL = sURL; W*1d X"S  
this.nStartPos = nStart; uZo]8mV  
this.nEndPos = nEnd; OaX HJ^k  
nThreadID = id; BXagSenc  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 qiF@7i  
} k8!hvJ)?  
^p{A!I!  
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public void run() ez{P-
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{ ,<R>Hiwg/s  
while(nStartPos < nEndPos && !bStop) R (+h)#![  
{ .aVHd<M  
5]A$P\7~1  
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try{ JNU"5sB  
URL url = new URL(sURL); [flu|v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); My'9S2Y8nv  
httpConnection.setRequestProperty("User-Agent","NetFox"); }Rf}NWU)|  
String sProperty = "bytes="+nStartPos+"-"; LZ=wz.'u  
httpConnection.setRequestProperty("RANGE",sProperty); <DA{\'jJ  
Utility.log(sProperty); r{;VTQ  
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InputStream input = httpConnection.getInputStream(); [XA&&EcU  
//logResponseHead(httpConnection); GqmDDL1  
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byte[] b = new byte[1024]; Huc3|~9  
int nRead; ox i a}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) o>/uW8  
{ /6i Tq^.%  
nStartPos += fileAccessI.write(b,0,nRead); ,6y-.m7>  
//if(nThreadID == 1) \F
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AaCnTRG  
} \UkNE5  
K#m\qitb  
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Utility.log("Thread " + nThreadID + " is over!"); >S-N|uR6  
bDownOver = true; S\yu%=h  
//nPos = fileAccessI.write (b,0,nRead); "Gi+zkVm  
} t?Njw7  
catch(Exception e){e.printStackTrace ();} &"~,V6,q  
} DRKc&F6Qy  
} vkNZ -`+I  
9^b7jw  
L:k@BCQM  
//打印回应的头信息 $w";*">:0  
public void logResponseHead(HttpURLConnection con) ur~Tql  
{ @@&@}IQcR1  
for(int i=1;;i++) ?-(w][MT\  
{ .5Z,SGBf  
String header=con.getHeaderFieldKey(i); 5W:Gl?$S}  
if(header!=null) kcma/d  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~,M;+T}[r  
Utility.log(header+" : "+con.getHeaderField(header)); b6?Xo/lJ.  
else 
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break; g#9*bF  
} mTb2d?NS  
} m\}\RnZu  
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public void splitterStop() RJ`/qXL  
{ pO7{3%  
bStop = true; tswG"1R  
} p[k9C$@e}  
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} !,-qn)b  
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/* RL]lt0O{  
**FileAccess.java ?G%, k LJJ  
*//文件访问(定位，写) [<3Q$*Ew  
package NetFox; u=ds]XP@  
import java.io.*; Sj]T{3mi  
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|]]pHC_/W  
public class FileAccessI implements Serializable{ Um0<I)  
vI:bl~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V"Y F
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RandomAccessFile oSavedFile; ][>M<J  
long nPos; C}DG'z9  
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public FileAccessI() throws IOException zf!\wY"`  
{ MkV*+LXC  
this("",0); OD@@O9  
} 5+Zx-oWq_  
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public FileAccessI(String sName,long nPos) throws IOException Y[8co<p  
{ krnk%
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oSavedFile = new RandomAccessFile(sName,"rw"); +EB,7<5<  
this.nPos = nPos; da86Jj=k  
oSavedFile.seek(nPos); wGQhr="  
} WUOPYYW<o
 
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t%YX-@  
public synchronized int write(byte[] b,int nStart,int nLen) 0f#a_  
{ jiB>.te  
int n = -1; Z_4H2HseL  
try{ '8pPGh9D
 
oSavedFile.write(b,nStart,nLen); -9<yB  
n = nLen; ^[?+=1 k  
} Kd[`mkmS  
catch(IOException e) (LvOs
r~  
{ @aPu}Hi  
e.printStackTrace (); Vi-!E  
} !vo'8r?&  
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return n; "E[*rnsLN  
} 6%hEs6-R  
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} 1X_!%Z  
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/* `r0 qn'*  
**SiteInfoBean.java q}24U3ow
 
*/ &l}xBQAL  
package NetFox; (a4y1k t-  
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public class SiteInfoBean { g:6}zHK  
5}^08Xl  
LFM5W&?  
private String sSiteURL; //Site's URL D@1
^:'$V  
private String sFilePath; //Saved File's Path [-94=|S @  
private String sFileName; //Saved File's Name gl{PLLe[}  
private int nSplitter; //Count of Splited Downloading File (V%vFD
1)  
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public SiteInfoBean() uC ;PP=z  
{//nSplitter的缺省值为5 l8Iy03H  
//default value of nSplitter is 5 +A3\Hj&W  
this("","","",5); iP\&fZY_  
} RpXGgw  
!_z>w6uR  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) -r0\  
{ y/*Tvb #TJ  
sSiteURL= sURL; >bP7}T  
sFilePath = sPath; >!.lr9(l  
sFileName = sName; &zDFf9w2{  
this.nSplitter = nSpiltter; @uD{`@[  
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} 1ORi]`  
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public String getSSiteURL() #EK8Qe_  
{ >V=@[B(0  
return sSiteURL; m&c(N  
} $=a$z"  
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public void setSSiteURL(String value) k(Xv&Zn  
{ '
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sSiteURL = value; UoT}m^ G  
} 6u3(G j@  
[:'?}p  
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public String getSFilePath() *%+buHe  
{ ee[NZz  
return sFilePath; y{P9k8v!z  
} HBGA lZ  
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5!p'n#_  
public void setSFilePath(String value) ZO$T/GE6%  
{ !Hj)S](F  
sFilePath = value; ?E@[~qq_  
} xM,(|p(  
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public String getSFileName() %*}f<k{6  
{ zwK;6&(W  
return sFileName; ~]+  jn  
} 2 ZXF_ o  
d'D\#+%>=  
{627*6,  
public void setSFileName(String value) iP_Xr~w  
{ E.9k%%X]  
sFileName = value; cNvcpv  
} _@76eZd  
feHAZ.8rp+  
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public int getNSplitter() I ^92b  
{ X.|0E87  
return nSplitter; ;Nij*-U4~  
} y$NG..S  
4+bsG6i  
!-~(*tn  
public void setNSplitter(int nCount) pdqh'+5  
{ `^{P,N>X  
nSplitter = nCount; ZeV)/g,w  
} X|G+N(`|(  
} z6(Q 3@iO  
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r U5'hK  
/* 7C^ nk z  
**Utility.java Y.#+Yh[  
*/ ^Yz05\  
package NetFox; b*fflJ  
iq-o$6Pg  
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public class Utility { {Wo7=a
R  
\$"
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public Utility() k*^W lCZ3  
{
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} dW68lVWq_  
YvX I  
//线程睡眠 3R {y
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public static void sleep(int nSecond) *Cw2h  
{ wt;aO_l  
try{ gG>>ynn  
Thread.sleep(nSecond); g(k|"g`*  
} 7/L7L5h<  
catch(Exception e) T:$_1I $  
{ wP*Z/}Uum+  
e.printStackTrace (); KHtY +93  
} ^cm^JyS)  
} zdE^v{}|  
oDa{HP\O]W  
//日志 /jD'o>  
public static void log(String sMsg) 4aC#Cv:0  
{ X$f%
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System.err.println(sMsg); J7xmf,
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} stPCw$@  
bSfQH4F  
tw66XxE  
public static void log(int sMsg) jLSZ#H  
{ x#D=?/~/Kv  
System.err.println(sMsg); 5,C,q%2  
} 7
}k8-:a%  
} }|,y`ui\  
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v
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/* oWmla*nCKL  
**TestMethod.java z{\.3G  
*/ 4KCxhJq  
package NetFox; $]FWpr%)  
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public class TestMethod { _q 8m$4  
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public TestMethod() <T).+ M/  
{ ///xx/weblogic60b2_win.exe \+xsJbEV  
try{ _Gu ;U@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); fvDwg  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); rzu^br9X  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ;Peyo1  
fileFetch.start(); Lmb<)YY  
} 2xX7dl(cC  
catch(Exception e){e.printStackTrace ();} y.zQ `  
Ty=}A MMyE  

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} E'Bt1u  
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public static void main(String[] args) y_6HQ:  
{ G;e}z&6<k  
new TestMethod(); V;"'!dVX  
} cnR>)9sX  
} "q$M\jK#V  
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