http断点续传简单实现（java)

/* -wUw)gJbM  
**SiteFileFetch.java *7:HO{P>Y  
*/ U1~6o"1H  
package NetFox; CZ.XEMN\  
import java.io.*; %MUh_63bB  
import java.net.*; a?5R;I B  
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public class SiteFileFetch extends Thread { fkWTO"f-  
v dR6y  
~ $QNp#dq  
SiteInfoBean siteInfoBean = null; //文件信息Bean c</u
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long[] nStartPos; //开始位置 ~LufHbr  
long[] nEndPos; //结束位置  %3A~&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +tSfx  
long nFileLength; //文件长度 jg+q{ ^  
boolean bFirst = true; //是否第一次取文件 xXn2M*g  
boolean bStop = false; //停止标志 R#w9%+  
File tmpFile; //文件下载的临时信息 'H.,S_v1x  
DataOutputStream output; //输出到文件的输出流 ]5`Y^hS_g  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） b am*&E%0K  
public SiteFileFetch(SiteInfoBean bean) throws IOException Mw9;O6  
{ ?> 7SZiC`  
siteInfoBean = bean; JMIS*njq^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `-QY<STTP9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); dxAP7v  
if(tmpFile.exists ()) g?=|kp  
{ u{dI[?@  
bFirst = false; Wp0L!X=0  
read_nPos(); C0.bjFT|  
} -|aNHZr  
else 'vV|un(6  
{ 0b~{l;  
nStartPos = new long[bean.getNSplitter()]; DS]C`aM9  
nEndPos = new long[bean.getNSplitter()]; :L'U>)k  
} Q@HW`@i  
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} 5^+QTQ  
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public void run() ;S_\- ]m&g  
{ ,OilGTQ#  
//获得文件长度 tH\ aHU[  
//分割文件 U#{^29ik=o  
//实例FileSplitterFetch pcl'!8&7  
//启动FileSplitterFetch线程 s)<^YASg  
//等待子线程返回 r|W2I,P  
try{ 3$Y(swc  
if(bFirst) yw3E$~k  
{ uv$t>_^  
nFileLength = getFileSize(); Ebk_(Py\  
if(nFileLength == -1) M^twD*  
{ = ^OXP+o  
System.err.println("File Length is not known!"); :6}y gL*i  
} JE$aYs<(TF  
else if(nFileLength == -2) n fU\l<  
{ ds9L4zfO  
System.err.println("File is not access!"); /18VQ  
} a&*fk?o  
else ">V.nao  
{ M*x1{g C/  
for(int i=0;i<nStartPos.length;i++) eJv_`#R&Of  
{ NrrnG]#p1  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); RV2s@<0p  
} ~c*$w O\  
for(int i=0;i<nEndPos.length-1;i++) DL:wiQ  
{ W@(EEMhw  
nEndPos = nStartPos[i+1]; 0s#
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} y>DvD)  
nEndPos[nEndPos.length-1] = nFileLength; lNw8eT~2
 
} -(Y(K!n  
} rnV\O L  
=ZaTD-%id  
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//启动子线程 jZX2)#a!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; yK #9)W-  
for(int i=0;i<nStartPos.length;i++) ,%zU5hh  
{ ",hPy[k  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,iQRf@#W_b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +U:U/c5Z^  
nStartPos,nEndPos,i); +v7mw<6s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9O.okU  
fileSplitterFetch.start(); tf5h/:  
} G; *jL4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N5SePA\ ,?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #EO@<>I  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", c9c_7g'q-  
nEndPos = " + nFileLength); ("7rjQjRz  
// fileSplitterFetch[nPos.length-1].start(); Hlr[x  
nX|f?5 O  
0E5
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//等待子线程结束 _8f? H#&  
//int count = 0; :=iP_*#  
//是否结束while循环 hPP,D\#  
boolean breakWhile = false; \.`;p  
/ehmy(zL  
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while(!bStop) ~'[0-_]=f  
{ w4m)lQM  
write_nPos(); BXCB/:0  
Utility.sleep(500); srh>" 2."  
breakWhile = true; gNsas:iGM  
*K<|E15 ,  
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for(int i=0;i<nStartPos.length;i++) =Z3{6y}3p  
{ " aEk#W  
if(!fileSplitterFetch.bDownOver) 7Ntt#C;]U  
{ 3($cBC  
breakWhile = false; V?.')?'V  
break; 907N;r  
} Cm~Pn"K_]  
}  MYD`P2F  
if(breakWhile) Zt;dPY
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break; 3u)NkS=  
.;1tu+S  
j>{Dbl:#2  
//count++; Hz*5ZIw  
//if(count>4) A*$JF>`7  
// siteStop(); ~6)A/]6  
} f6I$d<  
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qPn}$1+~  
System.err.println("文件下载结束！"); JZa^GW:YQh  
} ]~Su  
catch(Exception e){e.printStackTrace ();} `Mh3v@K:  
} p-6
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'@ $L}C#OI  
//获得文件长度 BrHw02G  
public long getFileSize() Cggu#//Z}Q  
{ u\jQe@j '  
int nFileLength = -1; B#|c$s{  
try{
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URL url = new URL(siteInfoBean.getSSiteURL()); 9_h V1:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nOH x^(
 
httpConnection.setRequestProperty("User-Agent","NetFox"); 8(6(,WwP}  
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int responseCode=httpConnection.getResponseCode(); ho'Ihep,L  
if(responseCode>=400) xF#'+Y  
{ t-;zgW5mwF  
processErrorCode(responseCode); +;T `uOF}  
return -2; //-2 represent access is error yobcAV`  
}
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String sHeader; nQtp4  
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for(int i=1;;i++) @L9C_a  
{ +E7Os|m  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @(m+B\  
//Utility.log(in.readLine()); Az`c? W%  
sHeader=httpConnection.getHeaderFieldKey(i); KE~l#=S  
if(sHeader!=null) __3s3YG  
{ yx@%x?B  
if(sHeader.equals("Content-Length")) uZg[PS=@!X  
{ -->~<o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); MXsCm(  
break; P<tHqN!q  
} j& H4L  
} AgBXB%).  
else =hP7Hea(N  
break; 6w"_sK?  
} k6}M7&nY  
} x @a3STKT  
catch(IOException e){e.printStackTrace ();} mr
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catch(Exception e){e.printStackTrace ();} PX} ~  
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Utility.log(nFileLength); kA"|PtrW  
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return nFileLength; OpNxd]"T  
} ,\Q^[e!m~  

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4ZX6=-u^  
//保存下载信息（文件指针位置） ,(@JNtx  
private void write_nPos() DD?zbN0X  
{ :kU-ol$  
try{ rP7[{'%r  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (*K=&e0O  
output.writeInt(nStartPos.length); # h/#h\  
for(int i=0;i<nStartPos.length;i++) n9w(Z=D\  
{ Bw{enf$vR  
// output.writeLong(nPos); 0DsW1  
output.writeLong(fileSplitterFetch.nStartPos); "C/X#y   
output.writeLong(fileSplitterFetch.nEndPos); c{,VU.5/  
} l(<=JUO;  
output.close(); n$u@v(I  
} 9sI&&Jg  
catch(IOException e){e.printStackTrace ();} ;S5J"1)O~  
catch(Exception e){e.printStackTrace ();} j`o_Stbg  
} 0^m`jD  
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//读取保存的下载信息（文件指针位置） yW)&jZb"(  
private void read_nPos() y(fJ{k   
{ Ds<~JfVl  
try{ GpZ}xY'|w,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Mjj5~by:  
int nCount = input.readInt(); tZL {;@  
nStartPos = new long[nCount]; >3qfo2K0  
nEndPos = new long[nCount]; zAkF:^#Y  
for(int i=0;i<nStartPos.length;i++) v[+ ]  
{ 4/?@%  
nStartPos = input.readLong(); \5pBK  
nEndPos = input.readLong(); lvd`_+P$  
} 5kx-s6`!  
input.close(); ~#];&WE  
} /=K(5Xd  
catch(IOException e){e.printStackTrace ();} 4Nl3"@<$  
catch(Exception e){e.printStackTrace ();} 6BdK)s  
} xa[)fk$6  
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}`uFLBG3  
private void processErrorCode(int nErrorCode) uefrE53  
{ i1 >oRT{Z  
System.err.println("Error Code : " + nErrorCode); HPc~wX  
} Aryp!oW  
X8\UTHT&0  
H
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//停止文件下载 x+8%4]u`  
public void siteStop() %:!ILN  
{ `Fx+HIng,  
bStop = true; E;rS"'D:  
for(int i=0;i<nStartPos.length;i++) Y.b?.)u&  
fileSplitterFetch.splitterStop(); @:Emmzucv|  
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} ;Xl {m`E+  
} U62Z ?nge%  
//负责部分文件的抓取 T$"sw7<  
**FileSplitterFetch.java `rest_vu  
*/ hYbaVE  
package NetFox; 'mTQ=1  
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import java.io.*; ]NyN@9u@(  
import java.net.*; v|R#[vtFd  
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public class FileSplitterFetch extends Thread { 7nPjeh  
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String sURL; //File URL &f
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long nStartPos; //File Snippet Start Position NXMZTZpB7  
long nEndPos; //File Snippet End Position u&Yd+');  
int nThreadID; //Thread's ID 2 b80b50  
boolean bDownOver = false; //Downing is over @:}la  
boolean bStop = false; //Stop identical B:VGa<lx5  
FileAccessI fileAccessI = null; //File Access interface 'iU+mRLp  
I23"DBR3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException VA@  
{ O4cBn{Dq9  
this.sURL = sURL; `$MO;Fv,G  
this.nStartPos = nStart; }yaM.+8.  
this.nEndPos = nEnd; jdkqJ4&i  
nThreadID = id; Ln8r~[tVE<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 nG%<n  
} bPIo9clq  
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@<yYMo7  
public void run() deEc;IAo  
{ 32Wa{LG;2  
while(nStartPos < nEndPos && !bStop) akG|ic-~  
{ KB{IWu  
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q|
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try{ n5y0$S/D  
URL url = new URL(sURL); M5
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -EE}HUP)  
httpConnection.setRequestProperty("User-Agent","NetFox"); I#'yy7J  
String sProperty = "bytes="+nStartPos+"-"; fg/hUUl  
httpConnection.setRequestProperty("RANGE",sProperty); !AGoI7W}  
Utility.log(sProperty); \hdil`{>  
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InputStream input = httpConnection.getInputStream(); eH~T PH  
//logResponseHead(httpConnection); >-y}t9[/  
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byte[] b = new byte[1024]; 7=s7dYlu  
int nRead; fOdX2{7m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R5\|pC  
{ iu$Y0.H@  
nStartPos += fileAccessI.write(b,0,nRead); >vXS6`;  
//if(nThreadID == 1) c<sq0('`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4wWfaL5"  
}  yyGn<  
2cwJ);Eg2  
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Utility.log("Thread " + nThreadID + " is over!"); k"6v& O  
bDownOver = true; f ~bgZ  
//nPos = fileAccessI.write (b,0,nRead); -j@IDd
7  
} !r9rTS]  
catch(Exception e){e.printStackTrace ();} _w2KUvG-8  
} R+2~%|{d  
} \Y`psSf+  
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//打印回应的头信息 ^gkKk&~A5?  
public void logResponseHead(HttpURLConnection con) 2wa'WEx  
{ DR]4Tcz#  
for(int i=1;;i++) ..w$p-1  
{ I:0dz:T7*  
String header=con.getHeaderFieldKey(i); *?VB/yO=0  
if(header!=null) 9< S  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); phB d+zQc  
Utility.log(header+" : "+con.getHeaderField(header)); %cJdVDW`L  
else c[$i)\0  
break; W@i|=xS?  
} ]:m4~0^#-(  
} J(A+mYr{:  
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public void splitterStop() 0.c96&
 
{ [z6P]eC7  
bStop = true; _ q AT%.  
} 1#8~@CQ ::  
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+n)
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} bJkFCI/  
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/* ylDfr){  
**FileAccess.java 7[i&EPN
 
*//文件访问(定位，写) j&b<YPZ  
package NetFox; o{ccO29H/  
import java.io.*; RWoVN$i>  
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public class FileAccessI implements Serializable{ Zu>CR_C  
bjN"H`Q  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $$*0bRfd4=  
RandomAccessFile oSavedFile; \`%#SmQF  
long nPos; {7q8@`Oa  

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?,C'\8'  
public FileAccessI() throws IOException ''k}3o.K[  
{ dEor+5}  
this("",0); 5d}bl{  
} ie7TO{W  
IxY!.d_s|~  
= N:5#A  
public FileAccessI(String sName,long nPos) throws IOException ?ZkVk=t?  
{ ?+$EPaC2  
oSavedFile = new RandomAccessFile(sName,"rw"); $N|Spp0  
this.nPos = nPos; faZc18M^1  
oSavedFile.seek(nPos); Xob(4  
} FY]Et=p  
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cCIs~*D  
public synchronized int write(byte[] b,int nStart,int nLen) $cLZ,N24  
{ tMo=q7ig  
int n = -1; .e}`n)z  
try{ eO{2rV45O  
oSavedFile.write(b,nStart,nLen); s5X51#J#~  
n = nLen; Hq,NOP  
} [kPl7[OL  
catch(IOException e) )Rj?\ZUR  
{ Ev48
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e.printStackTrace (); 5rJ7CfVq  
} I#W J";kqB  
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return n; 8Z 0@-8vi  
} 7qdB  
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0 Gq<APtr  
} ,rhNXx  
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/* kQrby\F(<  
**SiteInfoBean.java |lVi* 4za%  
*/ !ed0  
package NetFox; Nm3CeU  

xB}B1H%  
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public class SiteInfoBean { % "ZC9uq?  
sT91>'&  
iF"kR]ZL  
private String sSiteURL; //Site's URL gyCXv0*z  
private String sFilePath; //Saved File's Path rwAycW7  
private String sFileName; //Saved File's Name
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private int nSplitter; //Count of Splited Downloading File )U{IQE;T#  
~VPE9D@  
hTQ]xN)  
public SiteInfoBean() {%X[Snv  
{//nSplitter的缺省值为5 r
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//default value of nSplitter is 5 >< Qp%yT  
this("","","",5); Lx3`.F\m
G  
} 0|(6q=QK  
oCB#i~|>a  
g<i>25
2>  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) w.Go]dpK  
{ &lB>G[t  
sSiteURL= sURL; E
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sFilePath = sPath; t;lK=m|  
sFileName = sName; (KT+7j0^  
this.nSplitter = nSpiltter; {CGk9g"`  
=#vU$~a  
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} -4S4I  
L>,xG.oG  
R78lV-};Q  
public String getSSiteURL() QQUZneIDp  
{ 49 1 1  
return sSiteURL; -M`+hVs?  
} oh >0}Gc8  
/Fp@j/50  
4pFoSs?\  
public void setSSiteURL(String value) g|)yM^Vqr6  
{ !A"-9OS2  
sSiteURL = value; 4zf(  
} nkz^^q`5l7  
eo4v[V&  
'tq4-11xB  
public String getSFilePath() AJt4I W@  
{ Rhh.fV3  
return sFilePath; '_o(I  
} Qx77%L4  
2QV|NQSl  
}zHG]k,j  
public void setSFilePath(String value) =2, iNn  
{ t8"yAYj  
sFilePath = value; 4NmLbM&C8  
} DgC;1U'  
6"jV>CNc@  
lhJZPnx~  
public String getSFileName() :-1 i1d  
{ Y/G~P,9  
return sFileName; K=;oZYNd  
} ^9oJuT!tu  
UN`O*(k[  
rFYw6&;vOi  
public void setSFileName(String value) hSSFmEpr  
{ }e&Z"H |  
sFileName = value; R8fB 8 )  
} CYN|  
Z=>#|pW,)  
0-zIohSJdQ  
public int getNSplitter() el^WBC3  
{ N(L?F):fT  
return nSplitter; 2k"!o~s^  
} ?-9It|R  
R]Pv=fn  
.06[*S  
public void setNSplitter(int nCount) %n>*jFC  
{ >^%TY^7n  
nSplitter = nCount; >^ M=/+<c  
} <>^o
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} :/FT>UCL  
SHP
_  
~>|o3&G{  
/* nn6&`$(Q~  
**Utility.java [f\TnXq24  
*/ 8yn}|Y9Fu  
package NetFox; :sXn*k4v  
w&^_2<a2  
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public class Utility { YV
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7.`:Z_  
public Utility() h[I~D`q)v  
{ Dg2=;)"L  
) v^;"q"  
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} E]j2%}6Z%  
]-G10p}Ph-  
//线程睡眠 V50FX}i  
public static void sleep(int nSecond)
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MM  
{ ZF6?N?t}h8  
try{ $d_%7xx  
Thread.sleep(nSecond); T`.RP&2/d  
} XhEd9>#  
catch(Exception e) ]S#m o  
{ /K<.$B8  
e.printStackTrace (); Y]gb`z$?  
} E||[(l,b  
} aL%amL6CX  
pv #uLo  
//日志 WN%KATA  
public static void log(String sMsg) {(MC]]'?  
{ szx7CP`<8  
System.err.println(sMsg); ME%W,B.|"s  
} G 0;5I_D/  
%d/Pc4gfc  
Apx
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public static void log(int sMsg) 7$&3(#!N  
{ }+4^ZbX+:  
System.err.println(sMsg); PtT=HvP!k  
} Vx6/Rehj  
} Dtw1q-  
-1 Ok_h"  
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/* {q-<1|xj/J  
**TestMethod.java 6*n<emP  
*/ F qW[L>M'  
package NetFox;
_b8?_Zq  
- s,M+Q(<  
E8=8OX/{Y  
public class TestMethod { ]%y3*N@AZ  
c{dge/2yb  
>5Rcj(-&l  
public TestMethod() cnR.J  
{ ///xx/weblogic60b2_win.exe (ugB3o  
try{ ,c;u]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); VdZmrq;?/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5uU.K3G7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Gw5j6  
fileFetch.start(); $\ 0d9^)&  
} m.}Yn,
  
catch(Exception e){e.printStackTrace ();} DKG%z~R*  
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u
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} lo%:$2*'p  
8RfFP\AP  
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public static void main(String[] args) >(} I7  
{ MifPZQ  
new TestMethod(); RiY9[ec2  
} x!
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} Tjfg[Z/x  
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