http断点续传简单实现（java)

/* jq["z<V)x  
**SiteFileFetch.java 5Tpn`2F  
*/  aG\m3r  
package NetFox; ]'_z(s}  
import java.io.*; :7Vm]xd}do  
import java.net.*; !*|CIxk(  
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public class SiteFileFetch extends Thread { `bT{E.(T  
df1* [  
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SiteInfoBean siteInfoBean = null; //文件信息Bean i%*x7zjY{  
long[] nStartPos; //开始位置 SsznV}{^  
long[] nEndPos; //结束位置 H[,.nH_>+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ir\3c9  
long nFileLength; //文件长度 'KQuz)-  
boolean bFirst = true; //是否第一次取文件 &9s6p6eb  
boolean bStop = false; //停止标志 v,|
;uc+  
File tmpFile; //文件下载的临时信息 /2HwK/RZ  
DataOutputStream output; //输出到文件的输出流 XY4s  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） "-xC59,  
public SiteFileFetch(SiteInfoBean bean) throws IOException @/0aj  
{ K.z}%a  
siteInfoBean = bean; Wt3\&.n  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8:&@MZQ&!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ',!#?aGV  
if(tmpFile.exists ()) Pm?6]] 7  
{ s\jLIrG8  
bFirst = false; 2s{yg%U(  
read_nPos(); pb{P[-f  
} _~cmR<  
else ^5T{x>Lj  
{ <m(nZ'Zqz2  
nStartPos = new long[bean.getNSplitter()]; [U jbo
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nEndPos = new long[bean.getNSplitter()]; e8lF$[i  
} If&p$pAH?  
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} ttw@nv% @  
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public void run() XW#4C*5?d  
{ KcU,RTE  
//获得文件长度 df:,5@CJ8  
//分割文件 }%1E9u  
//实例FileSplitterFetch TRq~n7Y7C  
//启动FileSplitterFetch线程 LTY.i3  
//等待子线程返回 ~clWG-i  
try{ )T3wU~%  
if(bFirst) u3ZG;ykM  
{ eQLa.0  
nFileLength = getFileSize(); ^4fkZh  
if(nFileLength == -1) OS9v.pz  
{ AHA*yC  
System.err.println("File Length is not known!"); ;|^fAc~9{r  
} RTU:J67E  
else if(nFileLength == -2) wd]Yjr#%Ii  
{ zR .MXr  
System.err.println("File is not access!"); v8X&H
 
} )} #r"!  
else }"8_$VDcz  
{ TB[vpTC9)  
for(int i=0;i<nStartPos.length;i++) /Yh([P>  
{ Z kS*CG   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?~K2&eo  
} f65Sr"qB3  
for(int i=0;i<nEndPos.length-1;i++) Qh[t##I/  
{ O>Sbb2q?"  
nEndPos = nStartPos[i+1]; `WB|h)Y  
} X"0Q)  
nEndPos[nEndPos.length-1] = nFileLength; {k*_'0   
} 4[ra  
} QEgv,J{  
+ ND9###  
mOB\ `&h5  
//启动子线程 NLpD,q{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &zp5do;m  
for(int i=0;i<nStartPos.length;i++) P2p^
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{ <H)@vW]_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J$Q-1fjj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Dpd$&Wr0Y  
nStartPos,nEndPos,i); yU.0'r5uR  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _~kcr5  
fileSplitterFetch.start(); p(G?  
} ;Ki1nq5c#s  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FCWphpz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); twtDyo(\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", K)?^
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nEndPos = " + nFileLength); ~roHnJ>  
// fileSplitterFetch[nPos.length-1].start(); *LRGfk+h  
yjq )}y,tF  
Lk9>7xY  
//等待子线程结束 [1C#[Vla  
//int count = 0; ,lnuu  
//是否结束while循环 ?5Fj]Bk]  
boolean breakWhile = false; zEW:Xe)  
_iu|*h1y  
%\cC]<>  
while(!bStop) aK{\8L3]  
{ DVJc-.x8  
write_nPos(); i[pf*W0g  
Utility.sleep(500); 8j}
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breakWhile = true; LXLDu2/@  
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C=IH
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for(int i=0;i<nStartPos.length;i++) {nefS\#{  
{ ~@D%qbN  
if(!fileSplitterFetch.bDownOver) 6bNW1]rD  
{ |S{P`)z%f  
breakWhile = false; aA`q!s.%A  
break; }|Tg_+   
} >~rd5xlk  
} h'~-K`  
if(breakWhile) Ij1]GZ`A(  
break; j>xVy]v=|  
a*j <TR  
!&O/7ywe  
//count++; p*,P%tX  
//if(count>4) C|\^uR0  
// siteStop(); _}@n_E  
} 2g6_qsqi  
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OLNn3 J  
System.err.println("文件下载结束！"); $ bNe0  
} 51qIo4$  
catch(Exception e){e.printStackTrace ();} wLSZL  
} `E=rh3 L0o  
&&1Y"dFs  
.)>/!|i  
//获得文件长度 S}^s5ztm  
public long getFileSize() eCIRt/ uA  
{ mN{ajf)@  
int nFileLength = -1; z<6P3x|  
try{ Gv,92ny!|  
URL url = new URL(siteInfoBean.getSSiteURL()); 9c{%m4
  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hlFU"u_  
httpConnection.setRequestProperty("User-Agent","NetFox"); #)A?PO2  
fslk7RlSKg  
@P"`=BU&  
int responseCode=httpConnection.getResponseCode(); :F>L;mp  
if(responseCode>=400) |M<.O~|D6}  
{ 7e4tUAiuU  
processErrorCode(responseCode); N~}v:rK>g  
return -2; //-2 represent access is error d=(Yl r  
} 4 uy@ {  
p (xD/E  
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String sHeader; r(1pvcWY-  
}'V'Y[  
+z(,A  
for(int i=1;;i++) O&gwr  
{ \e:FmG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  %*5g<5  
//Utility.log(in.readLine()); a&s"#j  
sHeader=httpConnection.getHeaderFieldKey(i); :*P___S=  
if(sHeader!=null) Iz?Wtm }  
{ =!S@tuY  
if(sHeader.equals("Content-Length")) [wy3Ld  
{ Tc3ih~LvG  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m{lRFKx>s  
break; @0UwI
%.  
} SEQO2`]e:  
} }U?gKlLg  
else [2
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break; P96Cw~<Q?  
} F@_Egi  
} il
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catch(IOException e){e.printStackTrace ();} a(x.{}uG,  
catch(Exception e){e.printStackTrace ();} neB.Wu~WH  
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g`)/x\  
Utility.log(nFileLength); PK-}Ldj  
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return nFileLength; KM_)7?`  
} r:fwrC  
z{_mEE49  
fl!mYCPv  
//保存下载信息（文件指针位置） S9OxI$6Y  
private void write_nPos() ::p-9F  
{ PRMZfYc  
try{ Tx y]"_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1P5*wNF  
output.writeInt(nStartPos.length); h=X7,2/<  
for(int i=0;i<nStartPos.length;i++) Zr\2BOcc.l  
{ '9^E8+=|  
// output.writeLong(nPos); Hm.X}HO0L  
output.writeLong(fileSplitterFetch.nStartPos); zSEr4^Dk4  
output.writeLong(fileSplitterFetch.nEndPos); <$"7~i/X  
} cNdu.c[@  
output.close(); +ckMT
3  
} \z2vV+f  
catch(IOException e){e.printStackTrace ();} ?2H{^\<(e  
catch(Exception e){e.printStackTrace ();} V%i<;C  
} ; qO@A1Hq  
OpYmTep#T\  
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//读取保存的下载信息（文件指针位置） G"}qV%"6"  
private void read_nPos() cL6 6gOEL  
{ #o"tMh!f  
try{ ;_x2Ymw  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Vz%"9`r  
int nCount = input.readInt(); .8-PB*vb  
nStartPos = new long[nCount]; J=b*  
nEndPos = new long[nCount]; b21}49bHN  
for(int i=0;i<nStartPos.length;i++) :RPVT,O}  
{ @=CLeQG`  
nStartPos = input.readLong(); BeAk21xb  
nEndPos = input.readLong(); mG X\wta  
} &Y 'z?N  
input.close(); wtlB  
} 'zE: fLo  
catch(IOException e){e.printStackTrace ();} C2NzP& FD  
catch(Exception e){e.printStackTrace ();} OE6#
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} JAN|a
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private void processErrorCode(int nErrorCode) !5NGlqEF#  
{ xOhRTxic  
System.err.println("Error Code : " + nErrorCode); D
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} OthG7+eF  
#uB[&GG}W  
@sN^BX`z  
//停止文件下载 H%FM  
public void siteStop() anLbl#UV  
{ }&mj.
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bStop = true; av$  
for(int i=0;i<nStartPos.length;i++) !`Le`c  
fileSplitterFetch.splitterStop(); " l.!Ed  
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}
:r\xkHg/f  
} cFw3Iw"JJ  
//负责部分文件的抓取 bea|?lK  
**FileSplitterFetch.java L+7*NaPY*  
*/ bZu$0IG  
package NetFox; iEe#aO"D!  
A^8x1ydZ  
|"_)zQ  
import java.io.*; nVNs][  
import java.net.*; ,|A{!j`  
c+H)ed>  
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public class FileSplitterFetch extends Thread { Q~8y4=|#CY  
%Or2iuO%-,  
2g0K76=Co:  
String sURL; //File URL NfOp=X?Y  
long nStartPos; //File Snippet Start Position f*v1J<1#  
long nEndPos; //File Snippet End Position .3(;9};  
int nThreadID; //Thread's ID E_]k>bf\  
boolean bDownOver = false; //Downing is over 2!BsEvB(  
boolean bStop = false; //Stop identical =88t*dH(,"  
FileAccessI fileAccessI = null; //File Access interface .ByU  
h>| g2h  
i]dz}=j'  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException X'jr|s^s  
{ *l:&f_ngV  
this.sURL = sURL; \x(.d.l/  
this.nStartPos = nStart; ;sCU[4  
this.nEndPos = nEnd; RNvQ  
nThreadID = id; {79qtq%W{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位  J+lGh9G  
} JS PW>W"  
.8:+MW/  
22|"K**3J|  
public void run() Vli3>K&  
{ i0iez9B  
while(nStartPos < nEndPos && !bStop) @"w2R$o  
{ QE3ryD  
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try{ 1g~y]iQ  
URL url = new URL(sURL); ?|lIXz  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ox~ 9_d  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?d~]Wd!z  
String sProperty = "bytes="+nStartPos+"-"; KI`11lJW~  
httpConnection.setRequestProperty("RANGE",sProperty); zWb-pF|  
Utility.log(sProperty); UP]1(S?  
Qww^P/vm  
LJj=]_  
InputStream input = httpConnection.getInputStream(); Vha'e3o!  
//logResponseHead(httpConnection); F;-90w  
_F^$aZt?e  
bs BZE  
byte[] b = new byte[1024]; gJKKR]4*  
int nRead; Ch7Egzl7?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Tt%}4{"  
{ DRp&IP<  
nStartPos += fileAccessI.write(b,0,nRead); VyY.r#@  
//if(nThreadID == 1) Qm; BUG]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QkL@JF]Re  
} q1w|'V  
f1J%]g!  
wFb@1ae\  
Utility.log("Thread " + nThreadID + " is over!"); eC;!YGZ  
bDownOver = true; ;y OD  
//nPos = fileAccessI.write (b,0,nRead); LXNQ
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} `s%QeAde  
catch(Exception e){e.printStackTrace ();} vd(dNu&,<  
} hiN/S|JN8y  
} rREzM)GA  

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E(;i>   
//打印回应的头信息 l&Q!mU}  
public void logResponseHead(HttpURLConnection con) k}U JVH21k  
{ >XnO&h
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for(int i=1;;i++) )!sa)\E?  
{ (Q_2ODKo  
String header=con.getHeaderFieldKey(i); N Bz%(?\  
if(header!=null) yl/a:Q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); I="oxf#q  
Utility.log(header+" : "+con.getHeaderField(header)); cgN>3cE  
else :<%vE!$  
break; .Q[yD<)Ubs  
} TVeJ6

  
} Y&GuDLUF  
W_}/O'l{  
l#xw.2bo  
public void splitterStop() 0Cq!\nzz  
{ $"fzBM?5  
bStop = true; LS6ry,D"7  
} 'hI
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%w:'!X><  
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} 3+9 U1:1[.  
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/* fnOIv#  
**FileAccess.java }p{;^B  
*//文件访问(定位，写) #HG&[Ywi  
package NetFox; (Fqa][0  
import java.io.*; M=[th  
[%~^kq=|  
2fbU-9Rfn  
public class FileAccessI implements Serializable{ <A{y
($  
B@-"1m~la?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 lC2?sD$  
RandomAccessFile oSavedFile; ]ViOr8u  
long nPos; !&JiNn('  
h>|u:]I>  
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public FileAccessI() throws IOException gLx/w\l6  
{ |!xpYT:  
this("",0); s ^3[W0hL  
} Vrg3{@$  
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public FileAccessI(String sName,long nPos) throws IOException _k|g@"  
{ t\|J&4!Y  
oSavedFile = new RandomAccessFile(sName,"rw"); ]hKgA~;  
this.nPos = nPos; fCr\u6Tb  
oSavedFile.seek(nPos); yl]UUBcQ  
} u?Z <n:  
j[H
0SBKC  
hv{87`L'K(  
public synchronized int write(byte[] b,int nStart,int nLen) &D)2KD"N  
{ -nGwuEngP  
int n = -1; c"qPTjY  
try{ W]@6=OpH  
oSavedFile.write(b,nStart,nLen); {=6)SBjf  
n = nLen; Ysl9f1>%  
} ke^d8Z.  
catch(IOException e) h
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{ ;le0QA Pf  
e.printStackTrace (); w#<p^CS  
} '{CWanTPi  
.8x@IWJD
 
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return n; t*s!0'Y  
} ZqFUPHc  
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*V-
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} jNIUsM8e  
_{mJ.1)V;  
8 #Fh>  
/* 8UYJye8  
**SiteInfoBean.java &8afl"_~  
*/ fRFYJFc n  
package NetFox; 4ODX5If  
9':/Sab:7v  
I^@.Awt  
public class SiteInfoBean { uD[^K1Ag]^  
-aT=f9u  
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private String sSiteURL; //Site's URL ^^eV4Y5`+  
private String sFilePath; //Saved File's Path t%:G|n Sz  
private String sFileName; //Saved File's Name Uqr
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private int nSplitter; //Count of Splited Downloading File %^T!@uZr  
sjcQaF`=  
l)H9J]  
public SiteInfoBean() "!^c  
{//nSplitter的缺省值为5 cT I,1U  
//default value of nSplitter is 5 tbY SK  
this("","","",5); E::<;9  
} o:4CI  
Ir^BC!<2>  
l=,.iv=W  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) c9|I4=_K  
{ -h=c=P  
sSiteURL= sURL; W!y)Ho  
sFilePath = sPath; ]2P/G5C3tU  
sFileName = sName; pL%4= ]m  
this.nSplitter = nSpiltter; )S#j.8P'B  
SK}HXG{?  
5vYsA1Z
 
} V!\n3i?i  
"\}21B~{7'  
A7.JFf>  
public String getSSiteURL() !\3}R25  
{ $,g 3*A  
return sSiteURL; A<a2TXcIE3  
} ~T;K-9R  
eK\|SQb  
GCZu<,  
public void setSSiteURL(String value) {7/A  
{ ^GrNfB[Qu  
sSiteURL = value; 4{g:^?1=  
} -aC!0O y`  
^Kb9@lz/  
#*[,woNk  
public String getSFilePath() C:WtCAm(  
{ A>H*`{}  
return sFilePath; 3zk:59  
} wVlSjk  
h 3eGq:!9  
^ yY{o/6  
public void setSFilePath(String value) X+/{%P!w  
{ ;jp6 }zfI  
sFilePath = value; 3-4Nad  
} ^)(G(=-Rf  
D>psh-,1  
rE!G,^_{  
public String getSFileName() "cIGNTLFA  
{ A/ox#(!v  
return sFileName; Nck!z8  
} |`N$>9qN  
#nxER  
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public void setSFileName(String value) Wm];pqN  
{ 6GvhEulYR  
sFileName = value; !"Z."fm*  
} ex0 kb  
qz-#LZFTR  
%4QoF  
public int getNSplitter() buMiJzU  
{ <=B1"'\  
return nSplitter; ?Cc
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} 
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f\U?:83  
gOBj0P8s|}  
public void setNSplitter(int nCount) P wt ?9I  
{ Hsd|ka$x>  
nSplitter = nCount; +9=@E  
} 3n}sCEt=  
} mcAH1k e  
X_^_r{  
;]l{D}  
/* y<IZ|f  
**Utility.java 0ECO/EuCg  
*/ Vq)|gF[6i  
package NetFox; m!FM+kge  
c0,gfY%sI$  
<;TP@-a  
public class Utility { $=@9 D,R  
9.MGH2^L?  
)%H5iSNG$P  
public Utility() N9>'/jgZX  
{ =/!{<^0  
&VZmP5Gv  
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} J*^,l`C/  
\( Gf+  
//线程睡眠 '<{oYXZW3  
public static void sleep(int nSecond) e&FX7dsyy  
{ ZmR[5 mv@  
try{ 3^iQe"P%a@  
Thread.sleep(nSecond); 2yCd:wg  
} vo}_%5v8  
catch(Exception e) )N%1%bg^-  
{ "0!eb3n  
e.printStackTrace (); 709Uv5  
} {W:)oh>  
} E&T'U2  
i\DHIzGp[  
//日志 L(!!7B_,  
public static void log(String sMsg) .9[8H:Fe  
{ hsQrd%{f  
System.err.println(sMsg); }77=<N br  
} )W}/k$S  
f@xfb ie!  
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public static void log(int sMsg) X~Rk ,d3  
{ GqK&'c  
System.err.println(sMsg); tr9_bl&z  
} w'zO(6 `  
} _QOOx+%*5  
-<}>YtB Q  
#QyK?i*  
/* j O5:{%  
**TestMethod.java }5Tyz
i(  
*/ xjn8)C  
package NetFox; lz5j~t5>Q  
sOH
AW*+  
QO^X
7A"?X  
public class TestMethod { %+JTQy  
5DBd [u3  
]6 7wk  
public TestMethod() lMf5F8  
{ ///xx/weblogic60b2_win.exe 'WgwLE_  
try{ `\uv+^x{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); lGgKzi9VD  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 13@| {H CB  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @G{DOxE*  
fileFetch.start(); &otgN<H9  
} *Bz&  
catch(Exception e){e.printStackTrace ();} (ZSSp1Rv  
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)_ u'k /  
} P
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Q9V4-MC9  
#iU/Yg!  
public static void main(String[] args) ?
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{ hiM!htc;M  
new TestMethod(); 6>A8#VT  
} /;ITnG  
} a'~y'6  
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