http断点续传简单实现（java)

/* NZ=`iA8)X  
**SiteFileFetch.java kZJ.G  
*/ |)+;d  
package NetFox; N;.}g*_+}  
import java.io.*; < rqFBq8  
import java.net.*; r'~^BLT`#  
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public class SiteFileFetch extends Thread { WC *e#QP  
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SiteInfoBean siteInfoBean = null; //文件信息Bean J8:f9a:|M  
long[] nStartPos; //开始位置 wR*>9LjeG  
long[] nEndPos; //结束位置 6im!v<1Qx  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~T'Ri=  
long nFileLength; //文件长度 bL"!z"NA  
boolean bFirst = true; //是否第一次取文件 C)8>_PY[M  
boolean bStop = false; //停止标志 [6{o13mCWE  
File tmpFile; //文件下载的临时信息 %YbcI|i]<0  
DataOutputStream output; //输出到文件的输出流 RJO40&Z<Z  
+?[,{WtV  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） fBRU4q=^T  
public SiteFileFetch(SiteInfoBean bean) throws IOException B`i5lD  
{ ?O.1HEr  
siteInfoBean = bean; k7\ ,No}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @$ggPrs  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); *oca  
if(tmpFile.exists ()) "Acc]CqH*  
{ 7GVI={
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bFirst = false; Z[pMlg6Z  
read_nPos(); di5>aAJ)D  
} N6wCCXd  
else =vc8u&L2
 
{ `R+I(Cb  
nStartPos = new long[bean.getNSplitter()]; 4A@77#:J5  
nEndPos = new long[bean.getNSplitter()]; /yn%0Wish  
} xhmrep6+<  
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} @x@*=  
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public void run() jt?.g'  
{ /;rPzP4K6  
//获得文件长度 l6O8:XI  
//分割文件 Vim*4^[#L  
//实例FileSplitterFetch @#CZ7~Hn  
//启动FileSplitterFetch线程 8BgHoQ*  
//等待子线程返回 oR_qAb  
try{ 1{pU:/_W  
if(bFirst) #y:,owo3I  
{ m_pqU(sP  
nFileLength = getFileSize(); ~qP_1() ?  
if(nFileLength == -1) SV}C]<  
{ %zCV>D  
System.err.println("File Length is not known!"); ,2C{X+t  
} gvLzE&V}  
else if(nFileLength == -2) zIE{U  
{ ,9@JBV%_  
System.err.println("File is not access!"); U'K{>"~1a  
} OqcM3#  
else E)}& p\{E  
{ n^P~]1i   
for(int i=0;i<nStartPos.length;i++) zXRq) ;s  
{ pi|P&?yw  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /suW{8A(E  
} eKw!%97>  
for(int i=0;i<nEndPos.length-1;i++) rrL gBeQa  
{ 9KgGK cy%  
nEndPos = nStartPos[i+1]; ~Y.I;EPKt  
} o&Vti"fpC  
nEndPos[nEndPos.length-1] = nFileLength; 2/ES.>K!.  
} |0Y: /uL#)  
} ZJ Ke}F`l  
N">4I)  
eGF+@)K1"  
//启动子线程 `{GI^kgJ9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^KRe(  
for(int i=0;i<nStartPos.length;i++) _9<nM48+t  
{ 2b i:Q9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l}jC$B`5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), K\3N_ztu  
nStartPos,nEndPos,i); PDi]zp9>H  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xB<^ar  
fileSplitterFetch.start(); q<Sb>M/
\,  
} NZW)$c'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qjrl$[`X:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); CNkI9>L=W`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", (<ZpT%2  
nEndPos = " + nFileLength); N3rq8Rk  
// fileSplitterFetch[nPos.length-1].start(); 4J9VdEKk  
)4tOTi[  
 Z,Z4Sp  
//等待子线程结束 HkL`- c0  
//int count = 0; vv FH (W  
//是否结束while循环 aF!Im}  
boolean breakWhile = false; WNmG
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|@*3 nb8  
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while(!bStop) fb*h.6^y9  
{ *+|,rcI  
write_nPos(); t|jp]Vp  
Utility.sleep(500); jo}yeGbU  
breakWhile = true; z?I"[M  
+~[>Usf  
 Ww&r  
for(int i=0;i<nStartPos.length;i++) !+(c/ gwBh  
{ gx ]5)O  
if(!fileSplitterFetch.bDownOver) Krw'|<  
{ <<M1:1  
breakWhile = false; LyuA("xB#  
break; &`^PO$  
} qvs&*lBY  
} >f*-9  
if(breakWhile) "pInb5F  
break; 089 <B& <  
]p-xds#d  
/a7N:Z_Bz  
//count++; =v:}{~M^$  
//if(count>4) 2K VX  
// siteStop(); o^8Z cN>  
} 6F8TiR&  
vi;yT.  
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System.err.println("文件下载结束！"); 3o^~6A  
} ~LF1$Cai  
catch(Exception e){e.printStackTrace ();} rf=oH }  
} %F2T`?t:  
57jDsQAj  
=_=0l+\}  
//获得文件长度 >z|bQW#2  
public long getFileSize() zb,YYE1  
{ dIq*"Ry+~  
int nFileLength = -1; jb83Y>  
try{ K3.z>.F'h  
URL url = new URL(siteInfoBean.getSSiteURL()); 'A{B[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C-sFTf7  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~oX`Gih  
[R(dCq>  
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int responseCode=httpConnection.getResponseCode(); S[5OTwa8L  
if(responseCode>=400) q5G`N>"V  
{ Y1-=H)G  
processErrorCode(responseCode); W1 \dGskV  
return -2; //-2 represent access is error W!R7D%nX  
} .$U=ngj\t  
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h )% e  
String sHeader; P/,ezVb=  
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for(int i=1;;i++) U7xKu75G1  
{ o\
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Egi(z9|Pp  
//Utility.log(in.readLine()); 9ePR6WS4  
sHeader=httpConnection.getHeaderFieldKey(i); Aj{G=AT  
if(sHeader!=null) :qvA'.L/;z  
{ E^C [G)7n  
if(sHeader.equals("Content-Length")) `1i\8s&O6@  
{ _+ERX[i  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #}+_Hy  
break; ?.g="{5X  
} RV>n Op}R  
} l(Y\@@t1  
else X3j|J/  
break; [!j;jlh7},  
} =l4F/?u]f@  
} Z5`U+ (  
catch(IOException e){e.printStackTrace ();} S;}/ql y  
catch(Exception e){e.printStackTrace ();} BmFtRbR  
^0(`:*  
q rF:=?`E  
Utility.log(nFileLength); xgJyG.?  
p?#xd!tc2N  
/xb37,   
return nFileLength; 4Ix~Feuph  
} {k)H.zwe  
I3AxKA  
3^`.bm4 ^  
//保存下载信息（文件指针位置） d(q2gd@  
private void write_nPos() asJt6C  
{ }w5`Oig[  
try{ 'e*:eBoyb  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3A'9=h,lVK  
output.writeInt(nStartPos.length); fiQ/ &]|5  
for(int i=0;i<nStartPos.length;i++) F-<c.0;6  
{ vpP8'f.  
// output.writeLong(nPos);
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output.writeLong(fileSplitterFetch.nStartPos); X<uH [  
output.writeLong(fileSplitterFetch.nEndPos); @#::C@V]  
} ^)1!TewCY  
output.close(); h{CMPJjD  
} ?jn";:  
catch(IOException e){e.printStackTrace ();} N6h.zl&04  
catch(Exception e){e.printStackTrace ();} *lyRy/POB  
} i|N(=Z=  
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Q32GI,M%B  
//读取保存的下载信息（文件指针位置） lTZcbaO?]  
private void read_nPos() xz){RkVzP  
{ z<u@::  
try{ v;:. k,E0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  V/t-  
int nCount = input.readInt(); *?!A  
nStartPos = new long[nCount]; 6D29s]h2  
nEndPos = new long[nCount]; Z`yW2ON$'  
for(int i=0;i<nStartPos.length;i++) 0kL tL!3  
{ #IxCI)!I{[  
nStartPos = input.readLong(); $`txU5#vs  
nEndPos = input.readLong(); #4{9l SbU  
} }^ZPah  
input.close(); 2rqYm6  
} 84y#L[  
catch(IOException e){e.printStackTrace ();} 2^fSC`!  
catch(Exception e){e.printStackTrace ();} u<nPJeE  
} p 4Y2AQ9  
q&V=A[<rz  
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private void processErrorCode(int nErrorCode) e2Df@8>  
{ R|K#nh  
System.err.println("Error Code : " + nErrorCode); ''wF%q  
} ;op
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$-lP"m@}  
//停止文件下载 qj<_*  
public void siteStop() |^t8ct?x~  
{ T0lbMp
 
bStop = true; Q);^gV  
for(int i=0;i<nStartPos.length;i++) /Avl&Rd  
fileSplitterFetch.splitterStop(); E{E%nXR)  
:\,3=suWq  
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} Ng1uJa[k!d  
} Y?V>%eBu  
//负责部分文件的抓取 ]F1ZeAh5  
**FileSplitterFetch.java >@StKj  
*/ >T
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package NetFox; P*6&0\af|  
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import java.io.*; J2Eb"y>/;  
import java.net.*; -,}ppTG  
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public class FileSplitterFetch extends Thread { \7A6+[ `fa  
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+)-`$N  
String sURL; //File URL Avi8&@ya  
long nStartPos; //File Snippet Start Position /]"2;e-s+  
long nEndPos; //File Snippet End Position kV3Zt@+  
int nThreadID; //Thread's ID /WE1afe_R  
boolean bDownOver = false; //Downing is over  B!+`km5  
boolean bStop = false; //Stop identical 3bPF+(`J  
FileAccessI fileAccessI = null; //File Access interface $_NP4V8|z/  
.+Fh,bNYK  
[";<YR7iRN  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException J;cTEB  
{ V-%Am  
this.sURL = sURL; gTwxmp.,  
this.nStartPos = nStart; 5b-: e? |  
this.nEndPos = nEnd; m\?H <o0  
nThreadID = id; Jp]eFaqp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7cMSJM(]G  
} Rjz~n38.  
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*WpDavovyB  
public void run() fS(IN~
 
{ Ye) F{WqZ#  
while(nStartPos < nEndPos && !bStop) <X1^w  
{ "=9kX`(1y  
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try{ JJ$q*  
URL url = new URL(sURL); 9Lv"|S`5W_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); CN, oH4IU  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]:vo"{*C  
String sProperty = "bytes="+nStartPos+"-"; 'vUx4s  
httpConnection.setRequestProperty("RANGE",sProperty); 
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Utility.log(sProperty); 6!^&]4  
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InputStream input = httpConnection.getInputStream(); m'P,:S)=  
//logResponseHead(httpConnection); `@07n]KB  
aZ{]t:]  
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byte[] b = new byte[1024]; 9akIu.H  
int nRead; _r&,n\ T  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
'lD"{^  
{ L\Y4$e9bF8  
nStartPos += fileAccessI.write(b,0,nRead); a@&P\"k  
//if(nThreadID == 1) 8Mf{6&F=  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); HRxA0y=  
} hbg:}R=B<  
$D)Ajd;  
MF["-GvP/  
Utility.log("Thread " + nThreadID + " is over!"); 5x:dhkW  
bDownOver = true; @fSBW+  
//nPos = fileAccessI.write (b,0,nRead); =1'vXPv`  
} fNnemn@>  
catch(Exception e){e.printStackTrace ();} =xq+r]g6  
} n^2p jTkl  
} M$0-!$RY  
_#]/d3*Z}  
lEe<!B$d"  
//打印回应的头信息 A\v(!yg  
public void logResponseHead(HttpURLConnection con) @ =M:RA  
{ swh8-_[c/  
for(int i=1;;i++) 8A ;)5!  
{ _`(WX;sK  
String header=con.getHeaderFieldKey(i); K-CF5i:  
if(header!=null) z[`OYwsW  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); C>:'@o Z  
Utility.log(header+" : "+con.getHeaderField(header)); b,Vg3BS  
else 3</gK$f2  
break; H${5pY_M  
} Ghb Jty`  
} J>XMaI})U  
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f  
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public void splitterStop() 2/W5E-tn  
{ }; ;Thfd  
bStop = true; g VPtd[r  
} :ENdF `nC  
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} c?0.>^,B Q  
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/* t.`&Q|a  
**FileAccess.java Q`kJ3b  
*//文件访问(定位，写) v?=y9lEH@%  
package NetFox; v{[:7]b_=  
import java.io.*; +-*Ww5Zti  
zG. \xmp  
W#.+C6/  
public class FileAccessI implements Serializable{ ,&5\`  
R#^.8g)t  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [
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RandomAccessFile oSavedFile; %A^V@0K3  
long nPos; 15X.gx  
NlG~{rfI  
~]_U!r[FA  
public FileAccessI() throws IOException Ump$N#  
{ gZHuyp(B  
this("",0); %Y:"5fH  
} j LS<S_`  
S4hv7.A  
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public FileAccessI(String sName,long nPos) throws IOException P\lEfsuR  
{ T{:~v+I=  
oSavedFile = new RandomAccessFile(sName,"rw"); $"P[nNW3  
this.nPos = nPos; DQ*T2*L  
oSavedFile.seek(nPos); .;$Ub[
  
} kR,ry:J-  
rd:WF(]  
^kO+NH40  
public synchronized int write(byte[] b,int nStart,int nLen) x,% %^(  
{ R ~ZcTY[8  
int n = -1; y<5RV>"Vg  
try{ s ]XZQr%  
oSavedFile.write(b,nStart,nLen); / :z<+SCh  
n = nLen; x=M%QFe  
} sW^e D;  
catch(IOException e) /2.}m`5  
{ K8bKTG\  
e.printStackTrace (); =f/CBYNw@V  
} 0;Oe&Y  
xk*&zAt  
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return n; QHDR*tB:{  
} ]T:a&DHC  
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} -k8<LR3  
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/* $-MVsa9>I  
**SiteInfoBean.java BICG@  
*/ .mbqsb]&Y  
package NetFox; @u @~gEt  
9]Fi2M  
'CMbqLk#  
public class SiteInfoBean { U #C@&2  
akA7))Q  
1PB"1.wnd  
private String sSiteURL; //Site's URL dM=45$\q  
private String sFilePath; //Saved File's Path J6I:UML  
private String sFileName; //Saved File's Name [} zzG@g,J  
private int nSplitter; //Count of Splited Downloading File kz\Ss|jl  
\47djm
G-  
lHUd<kEC  
public SiteInfoBean() Gl"|t't(  
{//nSplitter的缺省值为5 N<PDQ  
//default value of nSplitter is 5 0MI4"<  
this("","","",5); 2{Y~jYt{h  
} Uc;~q-??#  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) p9>1a j2a  
{ k5%W8dI  
sSiteURL= sURL; -|GKtZ]}  
sFilePath = sPath; uCr :+"C  
sFileName = sName; ?o6X_UxW!  
this.nSplitter = nSpiltter; M>_vsI^I'  
^B)f!HtU  
QR2S6
7-  
} ~].?8C.>*  
CkV5PU  
ObfRwZh?q  
public String getSSiteURL() w^"IR  
{ v YJ9G"E  
return sSiteURL; ;_=N YG.  
} d9&   
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a$j ~YUG_  
public void setSSiteURL(String value) )qRH?Hsb7  
{ Vel}lQD  
sSiteURL = value; F8S>Ld  
} f{.4#C'  
-VeCX]  
B<Q)z5KK  
public String getSFilePath() .
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{ byFO^pce  
return sFilePath; l*?_@  
} Z]e`bfNnI  
+Bf?35LP  
s&hr$`V4  
public void setSFilePath(String value) i!x>)E  
{ YF)]B|I  
sFilePath = value; mqj-/DN6*  
} ~Pj q
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(3"N~\9m  
RfO
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public String getSFileName() 6O<UW.  
{ 1<Sg@  
return sFileName; f14^VTzP/#  
} RA!q)/+  
/5<=m:  
8t3m$<7  
public void setSFileName(String value) <.mH-Y5i  
{ 9Ta0Li  
sFileName = value; dU#-;/}o  
} CLTkyS)C  
q)mG6Su d  
0k#7LubWZl  
public int getNSplitter() *a\6X( ~  
{ 9O-2  
return nSplitter; QgI[#d{  
} y^"@$   
p- a{6<h  
~o>Gm>5!HH  
public void setNSplitter(int nCount) Zwm/c]6`  
{ W#%s0EN<_  
nSplitter = nCount; x_/}R3d  
} M.K^W`  
} D<m0G]Ht*  
X@"G1j >/  
mU]VFPr5  
/* qiB~  
**Utility.java D#G%WT/"  
*/ >{N}UNZ$}  
package NetFox; c:.~%AJx  
^nK<t?KS  
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public class Utility { .[}G{%M~[  
F#>00b{Q  
{vGJ}q?Sd"  
public Utility() +U1 Ir5Lx  
{ a%e`  
hbOXR.0z  
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} v
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e   
w`;HwK$ ,  
//线程睡眠 fz\Q>u'T  
public static void sleep(int nSecond) K Ax=C}9  
{ }b1FB<e]  
try{ ":_II[FPY  
Thread.sleep(nSecond); IH;sVT$M  
} p"#\E0GM  
catch(Exception e) %rMCiz  
{ =KUmvV*\  
e.printStackTrace (); a3>/B$pE  
} :{#O  
} b?l>vUgAg  
>UMxlvTg&  
//日志 4SZ,X^]I>  
public static void log(String sMsg) 1vxRhS&FY  
{ +?Ii=*7n  
System.err.println(sMsg); eD?&D_l~6  
} !+Xul_XG  
cf88Fd6l/  
f4h~c  
public static void log(int sMsg) R7/S SuG6\  
{ pY`$k#5  
System.err.println(sMsg); ts!tv6@  
} .P$m?p#  
} ]:Gy]qkO  
)
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%+H_V1F  
/* 3l~+VBR_  
**TestMethod.java W!wof-1  
*/ J(l\VvK  
package NetFox; PqV F}  
dMH_:jb  
|gA@WV-%  
public class TestMethod { >`\.i,X.D  
Jv8:GgSg
 
,7LfvZj4[  
public TestMethod() B;r_[^  
{ ///xx/weblogic60b2_win.exe 3'Y-~^ml|  
try{ ^Hv&{r77  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);  px<psR5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); pL"{Uqi  
SiteFileFetch fileFetch = new SiteFileFetch(bean); T82 `-bZ  
fileFetch.start(); :QGkYJ  
} oFj_o  
catch(Exception e){e.printStackTrace ();} ^e8xg=8(  
-K'UXoU1  
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} taE p   
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public static void main(String[] args) F:!6B bC  
{ B/wD~xC?x  
new TestMethod(); HG;;M6  
} "pM>TMAE  
} @."K"i'Bl  
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