http断点续传简单实现（java)

/* i1-%#YYF(  
**SiteFileFetch.java 
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*/ x\f~Gtt7Y  
package NetFox; Gn_DIFa  
import java.io.*; (V]3w  
import java.net.*; P)J-'2{  
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public class SiteFileFetch extends Thread { zB~<@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean WvSm!W  
long[] nStartPos; //开始位置 9OW8/H&!  
long[] nEndPos; //结束位置 pt,L  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 a !%,2|U  
long nFileLength; //文件长度 }(|gC,  
boolean bFirst = true; //是否第一次取文件 w}zmcO:x  
boolean bStop = false; //停止标志 ?+^p$'5
 
File tmpFile; //文件下载的临时信息 a.}#nSYP  
DataOutputStream output; //输出到文件的输出流 M*kE |q/K  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） IDFzyg_
 
public SiteFileFetch(SiteInfoBean bean) throws IOException yb?Pyq.D  
{ %xOxMK@  
siteInfoBean = bean; t'@mUX:-A  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); hr6j+p:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }&e HU  
if(tmpFile.exists ()) C49\'1\6  
{ ]\_tO  
bFirst = false; ce}A!v  
read_nPos(); }6/M5zF3  
} ~uty<fP  
else /pPHD]  
{ 3mo4;F,h9  
nStartPos = new long[bean.getNSplitter()]; 'yq?xlIj  
nEndPos = new long[bean.getNSplitter()]; f!w/zC .  
} \&;y:4&l8  
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ng!cK<p  
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} 85q/|9D  
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public void run() %\HPYnIe  
{ rxu_Ssd@"  
//获得文件长度 a(]&H "  
//分割文件 Z
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//实例FileSplitterFetch $sda'L5^p  
//启动FileSplitterFetch线程 #NYnZ^6e  
//等待子线程返回 : #CWiq("%  
try{ *YvtT(Gt  
if(bFirst) ;'8P/a$  
{ d\]KG(T  
nFileLength = getFileSize(); @ztT1?!e  
if(nFileLength == -1) S3Gr}N  
{ xsj,l@Ey  
System.err.println("File Length is not known!"); [,AFtg[  
} s0f+AS|}  
else if(nFileLength == -2) iIX%%r+  
{ N{HAWB{  
System.err.println("File is not access!"); i~]
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} >B**fZ~L  
else >*ls} q^  
{ w+ !c9  
for(int i=0;i<nStartPos.length;i++) 1Ys=KA-!_x  
{ zP #:Tv'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Su6kpC!EW  
} ]A%3\)r  
for(int i=0;i<nEndPos.length-1;i++) 0j!3\=P$  
{ NeY*l  
nEndPos = nStartPos[i+1]; qm!oJL  
} V=8db%^  
nEndPos[nEndPos.length-1] = nFileLength; w)+1^eW  
} K $- *  
} 81{8F  
e&VC}%m  
l%"DeRp,/  
//启动子线程 hHJvLs>^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; p7Wt(A  
for(int i=0;i<nStartPos.length;i++) }vZf&ib-   
{ -J+1V{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q=5aHH% |  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), +\Jo^\  
nStartPos,nEndPos,i); it\$Pih]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O~V^]  
fileSplitterFetch.start(); IdAh)#) 7  
} yO%^[c?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?m]vk|>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Dnw^H.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", XYWyxx5`  
nEndPos = " + nFileLength); %eDSo9Y  
// fileSplitterFetch[nPos.length-1].start(); by @qg:  
VtLRl0/  
_F6<ba}o3  
//等待子线程结束 ^t4^gcoZ4Z  
//int count = 0; f)T\  
//是否结束while循环 >o1dc*  
boolean breakWhile = false; #17 &rizl  
:VlA2Ih&q  
iRsB|7v[,  
while(!bStop) -z`FKej   
{ jSE)&K4nI  
write_nPos(); .J O3#  
Utility.sleep(500); gdf0  
breakWhile = true; EO)JMV?6  
(1D1;J4g  
t/Io.d   
for(int i=0;i<nStartPos.length;i++) MygAmV&  
{ 9 fB|e|  
if(!fileSplitterFetch.bDownOver) D2&d",%&f  
{ JyE-
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breakWhile = false; CjpGo}a/  
break; #G]IEO$M6  
} GbQi3%  
} #9|&;C5',!  
if(breakWhile) ; oa+Z:;f  
break; hE(R[hc  
g}<jn'@{  
2(DhKHrF  
//count++; CHKhJ v3+4  
//if(count>4) t~o"x.  
// siteStop(); .ifz9jM'  
} eWAD;x?.  
 `qs,V  
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System.err.println("文件下载结束！"); -8qCCV&1i  
} K-k!':K:  
catch(Exception e){e.printStackTrace ();} <Tgy$Hm  
} V>QyiB  
9{;L7`<  
#8et91qw  
//获得文件长度 L/:l>Ko>7  
public long getFileSize() }X{rE|@  
{ doL-G?8B  
int nFileLength = -1; 5wVJ.B~s  
try{ J;_4 3eS  
URL url = new URL(siteInfoBean.getSSiteURL()); AA=Ob$2$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iRrUIWx  
httpConnection.setRequestProperty("User-Agent","NetFox"); D{B?2}X  
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int responseCode=httpConnection.getResponseCode(); Bz }nP9  
if(responseCode>=400) G7&TMg7i  
{ $t%IJT  
processErrorCode(responseCode); M5WB.L[@q  
return -2; //-2 represent access is error 2@tnOs(*  
} mh}D[K=~%  
LH4#p%Pb%  
0C :8X   
String sHeader; =|i_T%a  
j ^j"w(a  
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for(int i=1;;i++) =Iop  
{ |-V:#1wR.]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &233QRYM  
//Utility.log(in.readLine()); (y]Z*p:EW  
sHeader=httpConnection.getHeaderFieldKey(i); L@H^?1*L?  
if(sHeader!=null) U_IGL  
{ o.!o4&WH  
if(sHeader.equals("Content-Length")) fPD.np}  
{ h_4*?w  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); p48enH8CO  
break;
_ VuWo  
} 0
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} WCsf_1  
else y-E'Y=j  
break; QO =5Q  
} L/rf5||@  
} P{A})t7  
catch(IOException e){e.printStackTrace ();} vgy.fP"@  
catch(Exception e){e.printStackTrace ();} K
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Utility.log(nFileLength); m)L50ot:/  
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return nFileLength; 5c::U=  
} <?B3^z$  
hdw.S`~}%  

.4v?/t1  
//保存下载信息（文件指针位置） qvc<_k^  
private void write_nPos() W2X`%Tx
0  
{ m:)&:Y0 (a  
try{ W|8VE,"7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); a,oTU\m C  
output.writeInt(nStartPos.length); PoaCnoNS  
for(int i=0;i<nStartPos.length;i++) kZG=C6a  
{ KE,.Evyu=  
// output.writeLong(nPos); D@&xj_#\}  
output.writeLong(fileSplitterFetch.nStartPos); 7~P2q/2E>  
output.writeLong(fileSplitterFetch.nEndPos); (NFrZ0  
} %@C8EFl%3  
output.close(); @LOfqQ$FE  
} *4 LS``  
catch(IOException e){e.printStackTrace ();} K[iAN;QCe%  
catch(Exception e){e.printStackTrace ();} ]|!|3lQ  
} nPvys~D  
mBwz.KEm<  
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//读取保存的下载信息（文件指针位置） %/I:r7UR{  
private void read_nPos()
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{ Yd4X*Ua  
try{ #3*cA!V.<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ct-eD-X{  
int nCount = input.readInt(); \Ki3ls  
nStartPos = new long[nCount]; (UkDww_!  
nEndPos = new long[nCount]; hiVa\s  
for(int i=0;i<nStartPos.length;i++) +&7V@  
{ P0m9($JBD  
nStartPos = input.readLong(); H 0+-$s;f  
nEndPos = input.readLong(); A<
|9</9z  
} X8m-5(uW  
input.close(); o;6~pw%  
} wb62($  
catch(IOException e){e.printStackTrace ();} :N<Qk  
catch(Exception e){e.printStackTrace ();} _fk}d[q0  
} Pi"?l[T0  
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w` +,  
private void processErrorCode(int nErrorCode) +H&/C1u  
{ }+m4(lpl  
System.err.println("Error Code : " + nErrorCode); Ydrh+  
} =aB+|E  
>/\TG8t,f  
,Gv}N&  
//停止文件下载 !IR cv a  
public void siteStop() _}[WX[Le{  
{ wA$?e}  
bStop = true; 7HW:;2dL  
for(int i=0;i<nStartPos.length;i++) ng+sK  
fileSplitterFetch.splitterStop(); <|k :%  
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} BC!) g+8  
} C _he=SV  
//负责部分文件的抓取 VB905%  
**FileSplitterFetch.java F#|y,<}<  
*/ kO}%Y?9d  
package NetFox; Mw,]Pt6~i  
s/@uGC0>  
pBe1:  
import java.io.*; 3q`f|r  
import java.net.*; MD$W;rk(Hn  
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public class FileSplitterFetch extends Thread { ffk>IOH  
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!x-__[#  
String sURL; //File URL 3M?O(oO  
long nStartPos; //File Snippet Start Position OP+*%$wR  
long nEndPos; //File Snippet End Position %|x9C,0p#  
int nThreadID; //Thread's ID .BJoY <P*  
boolean bDownOver = false; //Downing is over JJ1>)S}X-  
boolean bStop = false; //Stop identical (L4llZ;q  
FileAccessI fileAccessI = null; //File Access interface Vp; `!+z"  
;5;>f)diS  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Eg1TF oIWl  
{ ??e|ec2%  
this.sURL = sURL; CC^]Y.9  
this.nStartPos = nStart; <EqS ,cO^  
this.nEndPos = nEnd; Dn<3#V  
nThreadID = id; @nwVl8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 G?v<-=I  
} !D1#3?L  
L44|/~  
~6t<`&f  
public void run() #Ev}Gf+5Q  
{ fr`#s\JKw  
while(nStartPos < nEndPos && !bStop) aJv+BX_,  
{ r{?qvl!q  
0;LF>+fJ  
h{"SV*Xpk/  
try{ D8! Y0  
URL url = new URL(sURL); "Ia.$,k9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J#H,QYnf(L  
httpConnection.setRequestProperty("User-Agent","NetFox"); yz0#0YG7  
String sProperty = "bytes="+nStartPos+"-"; 5-0&`,  
httpConnection.setRequestProperty("RANGE",sProperty); 8fi'"  
Utility.log(sProperty); .n_Z0&i/w  
,#BD/dF  
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InputStream input = httpConnection.getInputStream(); "4xo,JUf  
//logResponseHead(httpConnection); .= ~2"P  
=/j!S|P  
/Bgqf,N |  
byte[] b = new byte[1024]; ?IQDk|<%  
int nRead; v B~VJKD  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &Oz  
{ 0?t;3z$n  
nStartPos += fileAccessI.write(b,0,nRead); ye(av&Hn  
//if(nThreadID == 1) %VB
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ys_LGfK  
} o1\N)%  
j*gZvbO;'L  
oR`rs[Kj  
Utility.log("Thread " + nThreadID + " is over!"); }9U_4k  
bDownOver = true; \c{sG\ >  
//nPos = fileAccessI.write (b,0,nRead); oH4zW5  
} /+B6oE>8  
catch(Exception e){e.printStackTrace ();} WF~x`w&\  
} 5{+>3J  
} Pbbi*&i  
wbr$w>n  
V%;dTCq  
//打印回应的头信息 Rf)|p;  
public void logResponseHead(HttpURLConnection con) XySkm2y  
{ f'"PQr^9  
for(int i=1;;i++) /T {R\  
{ ~C>;0a;<:  
String header=con.getHeaderFieldKey(i); `K@N\VM  
if(header!=null) lxZ9y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {4SaSv^/  
Utility.log(header+" : "+con.getHeaderField(header)); }+S
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else P()n=&XO6  
break; L$"x*2[A  
} %&H^UxC  
} )mAD<y+  
@\gE{;a8  
6)=;cc{Vr  
public void splitterStop() 6NyUGGRq  
{ O%bltNEx1  
bStop = true; NMg(tmh  
} nfZe"|d  
3rZPVR$))  
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} H_S"4ISS_  
8z|]{XW{  
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/* I4ZbMnO  
**FileAccess.java 6^jrv [d  
*//文件访问(定位，写) s!D?%  
package NetFox; xh<{
lZ)KJ  
import java.io.*; 3HR)H-@6@7  
+3AX1o%p,#  
Exv!!0Cd^  
public class FileAccessI implements Serializable{ Jk`l{N  
"g"%7jK  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 i&m6;>?`  
RandomAccessFile oSavedFile; !.iFU+?V  
long nPos; #68$'Rl"o1  
bM_fuy55Op  
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public FileAccessI() throws IOException &\5bo=5V  
{ ettBque  
this("",0); vd^Z^cpip  
} Xg
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{Z
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public FileAccessI(String sName,long nPos) throws IOException n/BoK6g  
{
xi<}n#  
oSavedFile = new RandomAccessFile(sName,"rw"); WSU/Z[\`H  
this.nPos = nPos; ;*nzb!u\\  
oSavedFile.seek(nPos); MYxuQ|w  
} DuAix)#FN9  
pnuwjU-  
d'Dd66  
public synchronized int write(byte[] b,int nStart,int nLen) I:al
[V2g  
{ .bV^u  
int n = -1; *GhV1# <  
try{ 9P#kV@%(0c  
oSavedFile.write(b,nStart,nLen); m4~~q[t  
n = nLen; R;U4a2~  
} 'tQp&pj  
catch(IOException e) e<A>??h^  
{ }43qpJe8U  
e.printStackTrace (); vz:VegS  
} (VCJn<@@  
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]<%NX $9\  
return n; gd%Ho8,T  
} +g1+,?cU  
>#T?]5Z'MF  
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} \Q|,0`  
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cuf]-C1_  
/* +uNMyVH  
**SiteInfoBean.java zrE{CdG%y  
*/ >wYmx4W>  
package NetFox; |{%$x^KyJ  
*cXi*7|=  
6I_4{  
public class SiteInfoBean { Y2ON!Rno  
Y>2#9LA  
\SgBI/L^  
private String sSiteURL; //Site's URL BP&]t1p  
private String sFilePath; //Saved File's Path J*%IvRg  
private String sFileName; //Saved File's Name 3F6A.Ny  
private int nSplitter; //Count of Splited Downloading File d[H`Fe6h  

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public SiteInfoBean() `6NcE-oJ  
{//nSplitter的缺省值为5 EuVA"~PA  
//default value of nSplitter is 5 Sq2 8=1%  
this("","","",5); j39"iAn  
} u?z,Vs"  
=yJV8%pa  
va#].4_  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Nd;pkssd  
{ }KftVnD?  
sSiteURL= sURL; SFEDR?s  
sFilePath = sPath; (A?w|/bZd  
sFileName = sName; 0}:Wh&g  
this.nSplitter = nSpiltter; )C0Iy.N-  
uXA}" f2  
S]e;p\8$Z  
} ( YZ2&  
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public String getSSiteURL()
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{ VhnIr#L+  
return sSiteURL; qckRX+P`  
} (II#9n)  
Z;dR:|%)  
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public void setSSiteURL(String value) %bG\  
{ ']^]z".H  
sSiteURL = value; @aB7dtM  
} "{bc2#F  
nF,zWr[x  
),%@X  
public String getSFilePath() mSEX?so=[  
{ LS-_GslE7\  
return sFilePath; ['6Sq@c)  
} NUuIhB+  
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u@Z6)r'  
public void setSFilePath(String value) r. rzU  
{ tp\d:4~R  
sFilePath = value; hfvC-f97L  
} au+:-Khm  
fNrpYR X  
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public String getSFileName() zCS }i_ p  
{ cw_B^f8^  
return sFileName; VEL!-e^X&  
} 3r?T|>|  
3n_t^=  
,RAP_I!_x  
public void setSFileName(String value) a]8W32  
{ *iSE)[W  
sFileName = value; $>wN:uN(  
} + :b"0pu-H  
Iq{/-,v  
Nk$|nn9#'  
public int getNSplitter() W=n Hi\jLV  
{ @cG+D  
return nSplitter; *oh,Va  
} >v1.Gm  
M pz9}[`3g  
ZpwFC7LW  
public void setNSplitter(int nCount) g/i.b&  
{ {3Dm/u%=9|  
nSplitter = nCount; _?Ly7*UML  
} 90=gP  
} A`I1G9s  
A#F6~QX(.9  
u3jLe=Y'\  
/* !G'wC0  
**Utility.java &}_tALg  
*/ Izfq`zS+\s  
package NetFox; O? 7hT!{  
_~y-?(46K  
mF
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public class Utility { |uJjO>8]|  
nbDjoZZ4  
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public Utility() *M$$%G(4  
{ J8&0l&~6  
>5t]Zlb`  
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} _akpW  
m9ky?A,  
//线程睡眠 a,xy38T<  
public static void sleep(int nSecond) 0p*
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{ w)>/fG|;  
try{ $WQm"WAKe  
Thread.sleep(nSecond); HoZsDs.XZ  
} x*:"G'zT  
catch(Exception e) u*T#? W?  
{ 8;3I:z&muQ  
e.printStackTrace (); 
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} R{9G$b1Due  
} ?:7$c  
OHH\sA  
//日志 Ma ]*Pled  
public static void log(String sMsg) YgQb(umK  
{ y@ c[S;  
System.err.println(sMsg); tR?)C=4,  
} {CgF{7`  
U6YQ*%mZ_  
J(,{ -d-E  
public static void log(int sMsg) a0`(*#P  
{ "~08<+  
System.err.println(sMsg); c$;Cpt@-j  
} byk9"QeY\  
} {@t6[g++  
0.^67'  
aOmQ<N]a  
/* ^W0eRT  
**TestMethod.java XU`vs`/  
*/ "OrF81  
package NetFox; ?Elt;wL(  
h0-CTPQ7A  
'pT8S  
public class TestMethod { c:-n0m'i  
-[z1r)RZ  
Z:VT%-
 
public TestMethod() 6 _#Cv
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{ ///xx/weblogic60b2_win.exe z'Ut9u  
try{ uA\KbA.c;U  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); I%mGb$Q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4CxU eq  
SiteFileFetch fileFetch = new SiteFileFetch(bean); DV!0zzJ  
fileFetch.start(); <t,lq  
} wf~n>e^e  
catch(Exception e){e.printStackTrace ();} .h
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x!fRT.,}  
} +"VXw2R_e  
rpL
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 [4mIww%  
public static void main(String[] args) Ro#O{  
{ LUA<N:  
new TestMethod(); yY80E[v  
} ]!WD">d:  
} t<SCrLbz  
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