http断点续传简单实现（java)

/* +<sv/gEt  
**SiteFileFetch.java !4T7@V`G  
*/ N?c!uO|h|  
package NetFox; +LaR_n[  
import java.io.*; (CY#B
%*
 
import java.net.*; G]gc*\4  
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}%S#d&wh$_  
public class SiteFileFetch extends Thread { p

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SiteInfoBean siteInfoBean = null; //文件信息Bean =L,7~9  
long[] nStartPos; //开始位置 @}_Wl<kn  
long[] nEndPos; //结束位置 Z':w X  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %kV #UzL  
long nFileLength; //文件长度 4X$|jGQ\  
boolean bFirst = true; //是否第一次取文件 _{?-=<V'_  
boolean bStop = false; //停止标志 m 8P`n  
File tmpFile; //文件下载的临时信息 ;~n^/D2.  
DataOutputStream output; //输出到文件的输出流 n?8xRaEf  
1oL3y;>iL  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） luCwP  
public SiteFileFetch(SiteInfoBean bean) throws IOException B[r04YGh  
{ azl!#%  
siteInfoBean = bean; G`,M?lmL  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); A{ . A1  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]Tn""3#1g  
if(tmpFile.exists ()) mh,a}bX{  
{ NoT%z$1n  
bFirst = false; Dn+hI_"#_  
read_nPos(); >]ZW.?
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} uQz!of%x  
else 9QEK|x`8  
{ ;~(yv|f6  
nStartPos = new long[bean.getNSplitter()]; d,0Klew  
nEndPos = new long[bean.getNSplitter()]; HEe_K!_  
}
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} T}Ve:S  
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public void run() SX[  
{ r)[Xzn   
//获得文件长度 `"y:/F"{
 
//分割文件 @$5=4HA  
//实例FileSplitterFetch {EyWS
f"  
//启动FileSplitterFetch线程 ?I;PJj  
//等待子线程返回 mIv}%hD  
try{ wfQImCZ>l  
if(bFirst) y`8jz,&.  
{ mtVoA8(6  
nFileLength = getFileSize(); #bGYd}BfD  
if(nFileLength == -1) 5GDg_
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{ 8Bx58$xRq  
System.err.println("File Length is not known!"); )Qh*@=$-  
} axz.[L_elB  
else if(nFileLength == -2) "$A5:1;  
{ -mG
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System.err.println("File is not access!"); o8N,mGj}  
} P}"uC`036  
else 7 /XfPF  
{ &M6Zsmo  
for(int i=0;i<nStartPos.length;i++) !>EK %
OO  
{ m`Pk)c0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Sn[/'V^$a  
} N@V:nCl  
for(int i=0;i<nEndPos.length-1;i++) LU+}iA)  
{ mi@ni+2Tn  
nEndPos = nStartPos[i+1]; !JA//{?  
} Nu@dMG<5  
nEndPos[nEndPos.length-1] = nFileLength; | &/_{T  
} d^d+8R  
} _3q}K  
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//启动子线程 =LKf.@]#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >FqU=Q  
for(int i=0;i<nStartPos.length;i++) B{>x  
{ 4++pK;I  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =-/sB>-C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), eZ{Ce.lNR  
nStartPos,nEndPos,i); bmO(tQS$5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I6PReVIb  
fileSplitterFetch.start(); qD,/Qu62  
} oObQN;A@6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xMFEeSzl>S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); sCE%./h]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )a<MW66  
nEndPos = " + nFileLength); {TaYkuWS  
// fileSplitterFetch[nPos.length-1].start(); ~"r(PCa@  
>S]"-0tGD=  
.HPa\b\L>  
//等待子线程结束 ba^/Ar(B  
//int count = 0; -x-EU#.G  
//是否结束while循环 6_>(9&g`zV  
boolean breakWhile = false; 2Mj_wc  
M"yOWD~s~  
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while(!bStop) GIhFOK  
{ 'u6n,yRm  
write_nPos(); H{1'- wB  
Utility.sleep(500); HF*j=qt!  
breakWhile = true;
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for(int i=0;i<nStartPos.length;i++) @Y!B~  
{ ^7YZ>^  
if(!fileSplitterFetch.bDownOver) mQ2=t%  
{ S{N=9934_  
breakWhile = false; Ey{p;;H  
break; gnw">H  
} ~bz$]o-<  
} 9K-,#a  
if(breakWhile) uobQS!  
break; sW
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//count++; F:8@ ]tA&  
//if(count>4) ;9'] na  
// siteStop(); d=dHY(ms]  
} eu'~(_2  
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|  
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System.err.println("文件下载结束！"); MhIHfW]b  
} 3rX40>Cs8  
catch(Exception e){e.printStackTrace ();} X2'XbG3  
} S" (Nf+ux  
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//获得文件长度
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public long getFileSize() C$4{'J-ZH  
{ Ok<,_yh  
int nFileLength = -1; j{6O:d6([$  
try{ -B#K}xL|x  
URL url = new URL(siteInfoBean.getSSiteURL()); 1 ]ePU8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;7*T6~tv  
httpConnection.setRequestProperty("User-Agent","NetFox"); yw{r:fy  
t :~,7  
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int responseCode=httpConnection.getResponseCode(); 8+H 0  
if(responseCode>=400) =]1
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{ H3( @Q^9  
processErrorCode(responseCode); &joP-!"  
return -2; //-2 represent access is error j1=su~  
} m[Mw2F  
i`=%
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9+ |W;  
String sHeader; plpb4> S  
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for(int i=1;;i++) zx@L sp  
{ c/V0AKkS 8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Z+=-)&L  
//Utility.log(in.readLine()); I@TH^8(  
sHeader=httpConnection.getHeaderFieldKey(i); N1"p ;czK  
if(sHeader!=null) ;
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{ T8d=@8g,%  
if(sHeader.equals("Content-Length")) Dw$RHogb~y  
{ F<Xtp8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); a'r1or4  
break; }KT$J G?  
} gw^W6v  
} 5&xbGEP$  
else ZD4aT1|Q7  
break; x+b.9f4xJ  
} + WT?p]  
} VCwC$ts  
catch(IOException e){e.printStackTrace ();} u"m TS&  
catch(Exception e){e.printStackTrace ();} BCtKxtbS  
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Utility.log(nFileLength); AQ,"):ofvT  
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return nFileLength; z[K)0@8 6  
} /IF?|71,m  
2/\I/QkTs  
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//保存下载信息（文件指针位置） ta^$&$l  
private void write_nPos() r! [Qpb-:  
{ p_)ttcpi1  
try{ )0g!lCfb  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `gyke2n  
output.writeInt(nStartPos.length); .`(YCn?\  
for(int i=0;i<nStartPos.length;i++) .1z=VLKF'  
{ hBVm;`  
// output.writeLong(nPos); pl$wy}W-  
output.writeLong(fileSplitterFetch.nStartPos); %(]B1Zg6,  
output.writeLong(fileSplitterFetch.nEndPos); ?bg /%o  
} |<O^M q  
output.close(); F{rC{5@fj  
} *9aI\#}  
catch(IOException e){e.printStackTrace ();} uGHM ]"!)  
catch(Exception e){e.printStackTrace ();} v=Q!ioE7  
} eu":\ks  
/1$u|Gs *  
7|jy:F,w%  
//读取保存的下载信息（文件指针位置） cI/}rZ+  
private void read_nPos() b"nkF\P@Fj  
{ f1sp6S0V\  
try{ $4qM\3x0,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #2"'tHf4  
int nCount = input.readInt(); 9+/D\|"{  
nStartPos = new long[nCount]; +SW|/oIU  
nEndPos = new long[nCount]; MWK)Bn  
for(int i=0;i<nStartPos.length;i++) @"wX#ot  
{ (!qfd Qq#  
nStartPos = input.readLong(); C6h[L  
nEndPos = input.readLong(); %LD(S*>7  
} mn*}U R  
input.close(); J8ScKMUN2  
} %oquHkX%OJ  
catch(IOException e){e.printStackTrace ();} %UhLCyC/  
catch(Exception e){e.printStackTrace ();} *{5/" H5  
} ;=k{[g 'gv  
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private void processErrorCode(int nErrorCode) $yq76  
{ g^7zDU&'  
System.err.println("Error Code : " + nErrorCode); '-Oh$hqCx|  
} 
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.v+W>
 

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//停止文件下载 a .?AniB0  
public void siteStop() _+H $Pa}?  
{ RLzqpE<rJ  
bStop = true; ?P4y$P  
for(int i=0;i<nStartPos.length;i++) $!TMS&Wk  
fileSplitterFetch.splitterStop(); -]{ _^
 
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} #2$wI^O  
} K9yZG
  
//负责部分文件的抓取 +XW1,ly~  
**FileSplitterFetch.java qg|ark*1u  
*/ j}`ku9S~  
package NetFox; E1dhj3+3  
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import java.io.*; Ts
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import java.net.*; 7oc Ng  
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public class FileSplitterFetch extends Thread { 7I@df.rf6J  
{v|ib112;  
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String sURL; //File URL og~a*my3  
long nStartPos; //File Snippet Start Position 3x7fa^umR  
long nEndPos; //File Snippet End Position 5rc3jIXc{|  
int nThreadID; //Thread's ID 9I$}=&"  
boolean bDownOver = false; //Downing is over :eT\XtxM~{  
boolean bStop = false; //Stop identical H q?
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FileAccessI fileAccessI = null; //File Access interface )?$@cvf  
m1X*I  
TTbJ9O<43  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException s&Al4>}.f  
{ XD|Xd|/ {  
this.sURL = sURL; uEG4^  
this.nStartPos = nStart;
;!lwB  
this.nEndPos = nEnd; bv7xh*/  
nThreadID = id; dmcY]m  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "%S-(ue:  
} VUP. \Vry  
GoH.0eQ^  
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public void run() 5wE6gRJ  
{ jC$~m#F  
while(nStartPos < nEndPos && !bStop) O '`|(L  
{ z@?y(E  
}NRt:JC  
vILB$%I  
try{ UH;bg}=8  
URL url = new URL(sURL); a`]ZyG*P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {7MY*&P$,  
httpConnection.setRequestProperty("User-Agent","NetFox"); v6|[p  
String sProperty = "bytes="+nStartPos+"-"; /~7M @`1  
httpConnection.setRequestProperty("RANGE",sProperty); mG@[~w+  
Utility.log(sProperty); +2}Ar<elP  
#7]>ozKm  
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InputStream input = httpConnection.getInputStream(); z4` :n.  
//logResponseHead(httpConnection); u$aN~6HG  
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byte[] b = new byte[1024]; Eza^Tbq%j?  
int nRead; AE`UnlUSF  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) n "^rS}Y]  
{ 1vCp<D9<  
nStartPos += fileAccessI.write(b,0,nRead); 0(9gTxdB  
//if(nThreadID == 1) Xc^(e?L4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m^0 I3;  
} S4_ZG>\VT  
+ 65<|0  
TiZ MY:^  
Utility.log("Thread " + nThreadID + " is over!"); k`]76C7  
bDownOver = true; Zy{hYHQ  
//nPos = fileAccessI.write (b,0,nRead); _ouZd.
 
} 8wZ $Hq  
catch(Exception e){e.printStackTrace ();} !{ _:k%B  
} H4{7,n  
} 'O9Yu{M  
DYC2bs>  
UEm4):/}  
//打印回应的头信息 g2*}XS3  
public void logResponseHead(HttpURLConnection con) $P#+Y,r~\  
{ 2chT^3e  
for(int i=1;;i++) 30(e6T;  
{ +W8#]u|  
String header=con.getHeaderFieldKey(i); :D>flZi  
if(header!=null) [nX{sM%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -;RAW1]}Y$  
Utility.log(header+" : "+con.getHeaderField(header)); V:+vB "  
else d{(Rs.GuP  
break; ;- Vs|X  
} hp}rCy|01  
} {!{T,_ J  
/X#OX8gb]  
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public void splitterStop() 9ao?\]&t  
{ f(K1,L:&7  
bStop = true; ;ByCtVm2  
} #q9BU:  
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} -xJ\/"A  
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}v?l0Gk(  
/* %?qzP'  
**FileAccess.java E)X_  
*//文件访问(定位，写) #>BC|/P}  
package NetFox; 2(e;pM2Dq  
import java.io.*; =&qfmq  
9c1q:>|  
(5[#?_~  
public class FileAccessI implements Serializable{ 36.mf_AM  
6(1 &6|o3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 S_VzmCi  
RandomAccessFile oSavedFile; -~lrv#5Q  
long nPos; !VrBoU4<d  
!}1l8Y  
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public FileAccessI() throws IOException BP4vOZ0$  
{ gB,Q4acjj  
this("",0); 4xFAFK~lx
 
} @:!%Z`  
mt e3k=17  
@e7_&EGR?  
public FileAccessI(String sName,long nPos) throws IOException fg1uqS1rg  
{ hKsx7`[  
oSavedFile = new RandomAccessFile(sName,"rw"); pH@yE Vf  
this.nPos = nPos; X\<a|/{V A  
oSavedFile.seek(nPos); Y!|};  
} (.{."  
m5KLi &R  
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public synchronized int write(byte[] b,int nStart,int nLen) mcQ\"9;pY  
{ 6jl{^dI  
int n = -1; pMp@W`i^6  
try{ }JT&lyO< b  
oSavedFile.write(b,nStart,nLen); pBQ[lPCY/  
n = nLen; F1
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} X&K,,C  
catch(IOException e) +ZBj_Vw*|  
{ ~n/:a  
e.printStackTrace (); K:pG<oV|}  
} MUN:}S  
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C
{ Z*5)  
return n; (hv}K*c{  
} .=c@ps  
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} xrJ0  
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/* [Kbna>`  
**SiteInfoBean.java O9p^P%U"  
*/ 0upZ4eN  
package NetFox; ,-Lv3  
2b:I.  
mFIIqkUAL  
public class SiteInfoBean { v\kd78,  
?/p."N:]H  
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private String sSiteURL; //Site's URL +.hJ[|F1&  
private String sFilePath; //Saved File's Path <)
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private String sFileName; //Saved File's Name _)#~D*3  
private int nSplitter; //Count of Splited Downloading File D,uT#P  
y|wR)\  
23q2u6.F`  
public SiteInfoBean() `7',RUj|D  
{//nSplitter的缺省值为5
_'s5FlZq  
//default value of nSplitter is 5 \z2d=
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this("","","",5); dBW#PRg  
} ['0^gN$:e  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8EI&}I  
{ Zo,]Dx  
sSiteURL= sURL; a+\s0Qo<  
sFilePath = sPath; HMR!XF&JjC  
sFileName = sName; 8ZO~=e  
this.nSplitter = nSpiltter; W8!8/IZbN  
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lt}U,p,S  
} ra\|c>[%  
aII:Pzh]B  
@;d7#!:cE  
public String getSSiteURL() Je` w/Hl/U  
{ Q9t.*+  
return sSiteURL; "S&1J8D|  
} z7lbb*
Xe  
nSU7,K`PM  
W@FGU  
public void setSSiteURL(String value) c<qJs-C4;  
{ ^#2Y4[@  
sSiteURL = value; *km- pp  
} jY\YSQ  
w;^7FuBaC  
0'*'%Iga  
public String getSFilePath() Cd7d-'EQn  
{ <NMOs"NB  
return sFilePath; UgLJV2M6  
} mHC36ba  
GJuU?h#:/{  
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public void setSFilePath(String value) )i>T\B  
{ DZ|/#- k  
sFilePath = value; 3bB%@^<  
} %] 7.E  
!^A t{[U  
*yA.D
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public String getSFileName() Bk~M^AK@~  
{ .'N#qs_  
return sFileName; {eo?vA8SE  
} /?QBMI  
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public void setSFileName(String value) cV)~%e/  
{ GD .>u  
sFileName = value; <3Hu(Jx<O  
} iD9hqiX&  
MMUw+jM4  
#Y<b'7yJ  
public int getNSplitter() b~FmX  
{ }L*cP;m#  
return nSplitter; KHXnB  
} pG:)u cj  
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r7p>`>_Q\  
public void setNSplitter(int nCount) zL3'',Ha  
{ doaqHri\,  
nSplitter = nCount; S-+^L|  
} meV RdQ  
} _26F[R1><~  
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bwh.ekf8  
/* qT L@N9  
**Utility.java GQ9g$&T  
*/ D<cHa |  
package NetFox; V]9?9-r  
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public class Utility { KcjP39@I  
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public Utility() `_v|O{DC{  
{ ^UK6q2[  
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} !P0
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q  
?wx|n_3<:  
//线程睡眠 D*j\g
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public static void sleep(int nSecond) w~g)Dz2G  
{ `4 A%BKYB  
try{ KmkPq]  
Thread.sleep(nSecond); ),)]gw71QW  
} [e'Ts#($A  
catch(Exception e) f/qG:yTV`  
{ Sf\mg4,  
e.printStackTrace (); oa|nQ`[  
} fhmqO0  
} fm\IQqIK%  
pJ5Sxgv{;  
//日志 DFt1{qS8@u  
public static void log(String sMsg) K(HP PM\  
{ ,tL<?6_  
System.err.println(sMsg); L[*Xrp;/&  
} I.\fhNxHY  
/^\6q"'  
'DQKpk'  
public static void log(int sMsg) (v8jVbg  
{ m>6,{g
)  
System.err.println(sMsg); pemb2HQ'4j  
} S0Y$$r  
} u#Qd`@p  
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/* FXOA1VEg  
**TestMethod.java l7P~_X_)"  
*/ fNx3\<~V=  
package NetFox; X] &Q^  
m>'sM1s  
fgP_NYfOj  
public class TestMethod { tq^H)  
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>_]j{}~\k  
public TestMethod() 
vd9><W  
{ ///xx/weblogic60b2_win.exe /nRi19a%xU  
try{ lM5Xw  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =?3D:k7z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); s7<x~v+^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); FHI`/  
fileFetch.start(); RI"A'/56  
} -lm\~VZT3  
catch(Exception e){e.printStackTrace ();} 0p_/eWww-  
nj~1y')  
C_Y^
<  
} YzSUJ=0/  
#|34(ML  
;z>)&F  
public static void main(String[] args) hX]vZR&R  
{ `bffw:;%  
new TestMethod(); =LS?:Mhm  
} jyf[O -  
} Qd 1Q~PBla  
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