http断点续传简单实现（java)

/* oqLM-=0<}  
**SiteFileFetch.java [SnnOqWw  
*/ {
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package NetFox; 7iI6._"!w  
import java.io.*; E=G"_ ^hCE  
import java.net.*; &bh%>[  
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#Uc0W  
public class SiteFileFetch extends Thread { w.AF7.X`1  
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SiteInfoBean siteInfoBean = null; //文件信息Bean VLLE0W _]  
long[] nStartPos; //开始位置 #Cj$;q{!  
long[] nEndPos; //结束位置 3Ryae/Nk  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 K<BS%~,I  
long nFileLength; //文件长度 w+^z{3>  
boolean bFirst = true; //是否第一次取文件 !(%^Tg=  
boolean bStop = false; //停止标志 G<dWh.|`=  
File tmpFile; //文件下载的临时信息 "Uk "  
DataOutputStream output; //输出到文件的输出流 d9@Pze">e  
=_\+6\_  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） {pzu1*  
public SiteFileFetch(SiteInfoBean bean) throws IOException rM|] }M=_V  
{ N:4oVi@Je  
siteInfoBean = bean; n]K`ofjl^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~s$ jiA1  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !)!<.x  
if(tmpFile.exists ()) y2_^lW%  
{ |._9;T-Yde  
bFirst = false; QTy xx  
read_nPos(); ?3=D-Xrb  
} :)djHPP*  
else D&)w =qIu  
{ hny(:Dj  
nStartPos = new long[bean.getNSplitter()]; 1u%e7  
nEndPos = new long[bean.getNSplitter()]; w
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} 2D?V0>
/  
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} h
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public void run() |aaoi4OJ  
{ r+#!]wNPe  
//获得文件长度 ;|.~'':  
//分割文件 ]<Ugg  
//实例FileSplitterFetch JQ[~N-  
//启动FileSplitterFetch线程 c@uNA0 p
 
//等待子线程返回 );m7;}gE  
try{ )/B' ODa  
if(bFirst) +!'rwD  
{ >3{l"SPU  
nFileLength = getFileSize(); Gtyy^tz[  
if(nFileLength == -1) )|d]0/<  
{ =9LeFrz  
System.err.println("File Length is not known!");  C0Oe$& _  
} t7(#Cuv-  
else if(nFileLength == -2) `.0WK  
{ Zn-F!Lsv  
System.err.println("File is not access!"); ]O\m(of R  
} P ~sX S  
else z. 6-D  
{ vz~QR i*  
for(int i=0;i<nStartPos.length;i++) H7I
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{ mvCH$}w8&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u>YC4&  
} +H'{!:e5  
for(int i=0;i<nEndPos.length-1;i++) *h H\H   
{ i6.HR?n  
nEndPos = nStartPos[i+1]; (|
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} O< \i{4}}  
nEndPos[nEndPos.length-1] = nFileLength; >~D-\,d|f  
} b!pG&7P  
} t/3t69\x  
;QiSz=DyA  
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//启动子线程 }H>}v/  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =Eh~ wm  
for(int i=0;i<nStartPos.length;i++) E\X:VQ9  
{ z-Ndv;:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .o&Vu,/H  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]W7e2:Hra  
nStartPos,nEndPos,i); I'qIc?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =:5o"g  
fileSplitterFetch.start(); _>k&,p]y  
} R)<PCe`vf  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),   OH*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {cW%i:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {]F};_  
nEndPos = " + nFileLength); ^1b/Y8&8A  
// fileSplitterFetch[nPos.length-1].start(); "SV#e4C.  
\QZ~w_  
A:?|\r  
//等待子线程结束 "P@jr{zvMd  
//int count = 0; j\uh]8N3<  
//是否结束while循环 cGE,3dsF[  
boolean breakWhile = false; uE}A-\G  
%:DH_0  
3T|xUY)G4  
while(!bStop) @C?.)#  
{ O\"k[V?.V  
write_nPos(); iz0GL&<  
Utility.sleep(500); .wb[cCUQ  
breakWhile = true; V*C%r:5 ,v  
[@PD[-2QG3  
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for(int i=0;i<nStartPos.length;i++) |BC/ERms  
{ j-R9=vB2  
if(!fileSplitterFetch.bDownOver) EJz?GM  
{ 0[O."9  
breakWhile = false; BKfkB[*F  
break; qpCNvhi  
} RXbhuI  
} ptlcG9d-  
if(breakWhile) A.%MrgOOX  
break; I\,m6=q  
wt(Hk6/B  
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//count++; B}&9+2M  
//if(count>4) kW!`vQm~  
// siteStop(); n$03##pf  
} _Z>I"m  
:CR1Oy9  
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System.err.println("文件下载结束！"); Y!K5?kk  
} |RA|nu   
catch(Exception e){e.printStackTrace ();} dHUcu@,  
} L#}HeOEi[  
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//获得文件长度 &{5v[:$  
public long getFileSize() z5k9|.hgw  
{ 6bacU#0o  
int nFileLength = -1; $}TK,/W  
try{ A$a>=U|Z8  
URL url = new URL(siteInfoBean.getSSiteURL()); [JzOsi~R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); dZ"B6L!^(  
httpConnection.setRequestProperty("User-Agent","NetFox"); j/Dc';,d.(  
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int responseCode=httpConnection.getResponseCode(); l"ZfgJ}W  
if(responseCode>=400) WbP wO  
{ @#?w>38y  
processErrorCode(responseCode); 2GB+st,  
return -2; //-2 represent access is error hHoc>S6^M  
} 4P(ysTuM  
d ~`_;.z  
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String sHeader; wRATe 0'
 
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for(int i=1;;i++) N)&(&2  
{ B\ITXmd   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3!OO_  
//Utility.log(in.readLine()); *@
C]\)  
sHeader=httpConnection.getHeaderFieldKey(i); H)Kt!v8  
if(sHeader!=null) 
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{ )HFl 0[vT  
if(sHeader.equals("Content-Length")) |9D;2N(&!  
{ Bp.z6x4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); NETji:d  
break; rP=!!fC1;  
} HJh9<I  
} 7ql&UIeQ  
else DOzJ-uww1  
break; j+E[[  
} _]Ei,Ua  
} 2|8&=K /  
catch(IOException e){e.printStackTrace ();} POouO/r$  
catch(Exception e){e.printStackTrace ();} @NY$.K#]  
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Utility.log(nFileLength); 02EbmP  
.).*6{_  
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return nFileLength; -54  
} P!Mz5QZ+  
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t\p_QWnF  
//保存下载信息（文件指针位置） jgb>:]:  
private void write_nPos() 9kkYD  
{ nKoc%TNqe  
try{ NVFgRJ&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }k-rOi'jL  
output.writeInt(nStartPos.length); 05+uBwH
 
for(int i=0;i<nStartPos.length;i++) :e&P's=
 
{ wkp|V{k  
// output.writeLong(nPos); >H,t^i}@  
output.writeLong(fileSplitterFetch.nStartPos); TAbC-T.EV  
output.writeLong(fileSplitterFetch.nEndPos); %mda=%Yn  
} cX64 X  
output.close(); /y\KLa  
} &f\ng{  
catch(IOException e){e.printStackTrace ();} #Moju  
catch(Exception e){e.printStackTrace ();} X5@rPGc  
} U =()T}b>  
#hBDOXHPf  
_a"\g9{%*  
//读取保存的下载信息（文件指针位置） fRTQ5V  
private void read_nPos() /}]Irj
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{ );$L#XpB  
try{ }b#KV?xgW  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _~M*XJ] `  
int nCount = input.readInt(); Tv;|K's'  
nStartPos = new long[nCount]; YdI|xu>0A^  
nEndPos = new long[nCount]; @Y#{[@Hp%  
for(int i=0;i<nStartPos.length;i++) !2('Cq_^  
{ T1@]:`&  
nStartPos = input.readLong(); ]i=\5FH e  
nEndPos = input.readLong(); k++Os'hSEY  
} (+Yerc.NQt  
input.close(); ACg5"  
} crJyk#_  
catch(IOException e){e.printStackTrace ();} BO b#9r  
catch(Exception e){e.printStackTrace ();} 1or4s{bmo  
} (~r"N?`  
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private void processErrorCode(int nErrorCode) ( _ZOUMe  
{ 89>U Koc?  
System.err.println("Error Code : " + nErrorCode); Z[baQO  
} G<C[A   
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//停止文件下载 ^/wvHu[#  
public void siteStop() i;1aobG  
{ /5@V $c8  
bStop = true; ZJ} V>Bu-  
for(int i=0;i<nStartPos.length;i++) ,X&lVv#  
fileSplitterFetch.splitterStop(); r*K[,  
t)n!];  
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} K.cMuh  
} .0:twj  
//负责部分文件的抓取 'H<0:bQ=I  
**FileSplitterFetch.java yWa-iHWC
 
*/ ?|8H|LBIr  
package NetFox; 'aQ"&GX@  
s[|sfqB1`  
yz}Agc4.I  
import java.io.*; *KO4H  
import java.net.*; DFKU?#R  
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public class FileSplitterFetch extends Thread { u/e-m/  
`}ak;^Me  
#`5{?2gS9  
String sURL; //File URL }qlU  
long nStartPos; //File Snippet Start Position >&m
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long nEndPos; //File Snippet End Position i DV.L  
int nThreadID; //Thread's ID @Iz vObK  
boolean bDownOver = false; //Downing is over TC1#2nE&T  
boolean bStop = false; //Stop identical CUgXpU*  
FileAccessI fileAccessI = null; //File Access interface &Avd  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException w#wlZ1f  
{ A0sydUc  
this.sURL = sURL; TTaSg\K  
this.nStartPos = nStart; M7&u_Cn?  
this.nEndPos = nEnd; E%\jR  
nThreadID = id; 7pDov@K<{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %j%}iM/(<  
} TIbqUR  
(i^3Lw :  
hM")DmvB4  
public void run() 3!M;Z7qF]  
{ LC/9)Sh_n  
while(nStartPos < nEndPos && !bStop) ,.tv#j|A  
{ DTrS9j?z  
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6/@"K HHVe  
try{ R{.5Z/Vp6E  
URL url = new URL(sURL); 2mAXBqdm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _Z'j%/-4@D  
httpConnection.setRequestProperty("User-Agent","NetFox"); jZu">Eh,  
String sProperty = "bytes="+nStartPos+"-"; Qhb].V{utV  
httpConnection.setRequestProperty("RANGE",sProperty); )=TD}Xb  
Utility.log(sProperty); l\7NR  
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InputStream input = httpConnection.getInputStream(); rMIr&T  
//logResponseHead(httpConnection); }R:eKj  
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byte[] b = new byte[1024]; kxt@t#  
int nRead; >=-w2&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qy=4zOOD#  
{ l`8S1~j
 
nStartPos += fileAccessI.write(b,0,nRead); mMm_=cfv  
//if(nThreadID == 1) '"LrGvkZ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Wf/Gt\?  
} `#B|l+baq  
@O9.~6  
M7{w7}B0@  
Utility.log("Thread " + nThreadID + " is over!"); 4VINu9\V  
bDownOver = true; v'0A$`w`  
//nPos = fileAccessI.write (b,0,nRead); r=6-kC!T9  
} mY?^]3-_  
catch(Exception e){e.printStackTrace ();} ,-^Grmr4M  
} 22S4q`j  
} }
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//打印回应的头信息 T X.YTU  
public void logResponseHead(HttpURLConnection con) ,R/HT@  
{ s7=CH  
for(int i=1;;i++) 0FmYM@Wc  
{ :4s{?IY
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String header=con.getHeaderFieldKey(i); R{GOlxKs C  
if(header!=null) ^6s<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); OcQ>01
Q  
Utility.log(header+" : "+con.getHeaderField(header)); ]TQ2PVN2  
else i:W.,w%8  
break; xrDHXqH  
} NfizX!w&  
} <EFA^,3t%  
~pA_E!3W  
8P5yaS_  
public void splitterStop() =Tv|kJ| j  
{ nN1\  
bStop = true; h^R EBPe  
} ZaJg$  
}SYR)eE\  
(c;F%m|  
} KdIX`  
|Qo`K%8  
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/* a^_\#,}  
**FileAccess.java ?g gl8bzA  
*//文件访问(定位，写) a@:(L"Or  
package NetFox; pEgQ) 9\  
import java.io.*; d_s=5+Yj  
!$
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_/Ky;p.  
public class FileAccessI implements Serializable{ Hx[YHu KL^  
.CGPG,\2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 wSoIU,I  
RandomAccessFile oSavedFile; ^R- -&{I  
long nPos; jp=z ^l  
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"D#+:ix8G|  
public FileAccessI() throws IOException <QbD ;(%  
{ ^o&3+s}M  
this("",0); zOJ4I^^  
} d-/{@   
| a001_Wv  
pQv`fr=  
public FileAccessI(String sName,long nPos) throws IOException 3!E*h0$}  
{ jb;!"HC  
oSavedFile = new RandomAccessFile(sName,"rw"); dqF]kP,VG  
this.nPos = nPos; FYPv:k  
oSavedFile.seek(nPos); d%+oCoeb  
} to9~l"n.s  
Ls
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|@'/F#T  
public synchronized int write(byte[] b,int nStart,int nLen) 1;_tu  
{ 2I'gT$h  
int n = -1; Y%<y`]I  
try{ "#zSk=52z
 
oSavedFile.write(b,nStart,nLen); wEd+Ds]$  
n = nLen; e4:,W+g,9  
} NGQBOV  
catch(IOException e) {A!1s;  
{ Jr|"QRC  
e.printStackTrace (); Hq<Sg4nz  
} aumWU{j=  
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return n; b
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} >]b>gc?3  
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|,YyuCQcL[  
} FP
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/* nV`n=x  
**SiteInfoBean.java R<\5q%@G  
*/ sKE7U>mz|  
package NetFox; m@(8-_  
\iN3/J4  
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public class SiteInfoBean { cf\PG&S  
r.-U=ql  
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private String sSiteURL; //Site's URL h>0R!Rl8  
private String sFilePath; //Saved File's Path ~HW8mly'  
private String sFileName; //Saved File's Name C1V:_-  
private int nSplitter; //Count of Splited Downloading File M:[rH  
k[_)5@2  
W^(:\IvV  
public SiteInfoBean() gteG*pi  
{//nSplitter的缺省值为5 BH`%3Mw  
//default value of nSplitter is 5 ~Qg:_ @@\  
this("","","",5); /-C`*P=:u  
} fRcs@yZnS  
"pZvV0'  
%R?B=W7;Q  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) G 51l_  
{ Wi;wu*  
sSiteURL= sURL; ~ShoU m[  
sFilePath = sPath; ;FQ<4PR$  
sFileName = sName; <^+x}KV I  
this.nSplitter = nSpiltter; N~=,RPjq  
OV~]-5gau  
Xl/SDm_p  
} NA :_yA"  
s%cfJe_k  
H$@5\pP>  
public String getSSiteURL() HpXQD;  
{  L- '{
  
return sSiteURL; B,xohT  
} d O})#50f  
fen~k#|l  
SlaHhq3  
public void setSSiteURL(String value) y^u9Ttf{  
{ #7*{ $v  
sSiteURL = value; eb` !  
} :cE6-Fv  
}CM</  
 S6d&w6  
public String getSFilePath() mm1fG4 *%  
{ .="/n8B  
return sFilePath; }G/#Nb)  
} w;OvZo|  
u4KP;_,m  
gs:V4$(p4  
public void setSFilePath(String value) j@o \d%.'!  
{ kq4ii`zi8  
sFilePath = value; cWU9mzsE  
} G~+BO'U9'G  
<i$ud&D  
wCitQ0?  
public String getSFileName() >WZ_) `R  
{ Ovhd%qV;Y  
return sFileName; ! N!A%  
} 0XzrzT"&  
J$>9UCk7B  
i]
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public void setSFileName(String value) w9aLTLv-  
{ /\wm/Yx?S  
sFileName = value; JVe!(L4H  
} v1`*}.#  
!uc"|S?  
bm\Zp  
public int getNSplitter() {aoG60N  
{ Uaz$<K6  
return nSplitter; /lb"g_  
} %2ZWSQD  
?.~hex#M@  
q(s&2|  
public void setNSplitter(int nCount) l\DcXgD x  
{ aWk1D.  
nSplitter = nCount; w7e+~8|  
} +#RqQ8\  
} 8`Iz%rw&(J  
.Gcs/PN  
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/* -RBH5+SS2  
**Utility.java G9AQIU%ii  
*/ Mrly(*!U"@  
package NetFox; %4I13|<A`  
!)//b]  
wqE+hKs,  
public class Utility { zy\R>4i'#Q  
slH3c:j\  
)+dd  
public Utility() #,jw! HO]  
{ +2 x|j>  
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%<rV~9:  
} (!:+q$#BK  
PCX X[N  
//线程睡眠 ( SiwO.TZ  
public static void sleep(int nSecond) VI(2/**  
{ PlC8&$
  
try{ i}e4P>ADD  
Thread.sleep(nSecond); 7T/hmVi_  
} ?Vo/mtbY5X  
catch(Exception e) q6AL}9]9  
{ Br}0dha3E  
e.printStackTrace (); m-AW}1:\f  
} =&x u"V  
} e;r?g67  
"jA?s9  
//日志 2&KM&NX~  
public static void log(String sMsg) th]pqhl>  
{ 9`|~-b  
System.err.println(sMsg); o`%;*tx  
} GI[XcK^*w  
;Sw%t(@  
g?>V4WF  
public static void log(int sMsg) 0s o27k  
{ i$"M'BG  
System.err.println(sMsg); 4fgYO]  
} V}po  
} z8*{i]j  
NKRI|'Y,  
|L%d^m  
/* y8/+kn +  
**TestMethod.java Mx_
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*/ ^M7pCetjdW  
package NetFox; ZO\x|E!b  
@*"H{xo.U  
0;n}{26a  
public class TestMethod { ]>H'CM4JR  
x/,(G~  
XyrQJ}WR|  
public TestMethod() m={TBV,L  
{ ///xx/weblogic60b2_win.exe iVAAGZ>am  
try{ Uk<2X
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0.!!rq,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /;9iDjG  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [z> Ya-uz7  
fileFetch.start(); zA%$l&QN]  
} VB&`g<  
catch(Exception e){e.printStackTrace ();} M#o'hc  
4>}qdR1L4  
=,
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} b5t:">wC  
ql2O%B.6?  
Rr"D)|Y;C(  
public static void main(String[] args) Kp?j\67S  
{ }&Kl)2:O  
new TestMethod(); TM<;Nj[*n  
} SU>cJ*  
} u7}C):@H  
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