http断点续传简单实现（java)

/* kfs[*ku  
**SiteFileFetch.java -=4:qQEw  
*/ 7MwS[N%#  
package NetFox; `mDCX  
import java.io.*; 6"U$H$i.G  
import java.net.*; `R_;n#3F0  
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public class SiteFileFetch extends Thread { Nb/Z+  
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SiteInfoBean siteInfoBean = null; //文件信息Bean .arWbTR)~U  
long[] nStartPos; //开始位置 sK|+&BC
 
long[] nEndPos; //结束位置 "l-R|>6~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Uf\U~wM<  
long nFileLength; //文件长度 $xq$  
boolean bFirst = true; //是否第一次取文件 9at_F'>R  
boolean bStop = false; //停止标志 I73=PfS:m  
File tmpFile; //文件下载的临时信息 2j-^F  
DataOutputStream output; //输出到文件的输出流 V\r2=ok@y  

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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） :Mnl1;oh  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7SJtW`~  
{ 3|1v)E  
siteInfoBean = bean; Qis/'9a  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [|APMMYK1  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); l[b`4  
if(tmpFile.exists ()) A0gRX]  
{ )s>R~7  
bFirst = false; uwWKsZ4:ij  
read_nPos(); \ H!Klp  
} /yTPb  
else KWiP`h8  
{ G Y+li{  
nStartPos = new long[bean.getNSplitter()]; t,308Z  
nEndPos = new long[bean.getNSplitter()]; h=MEQ-3jg  
} 6[&x7"  
=]W[{@P  
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} ?4YLt|sn  
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public void run() v1\/dQK  
{ J42/S [Rt  
//获得文件长度 Apc!!*7  
//分割文件 . MH;u3U  
//实例FileSplitterFetch 2 UPG8]  
//启动FileSplitterFetch线程 \MB$Cwc  
//等待子线程返回 +W}6o3x~  
try{ VqnM>||  
if(bFirst) LHd9q^D  
{ x^)W}p"  
nFileLength = getFileSize(); JO&L1<B{v  
if(nFileLength == -1) Eanwk` Rx  
{ 6=g! Hs{  
System.err.println("File Length is not known!"); V ^hR%*i'  
} O{ |Ug~  
else if(nFileLength == -2) #= @?)\~  
{ dc,qQM  
System.err.println("File is not access!"); b-HELS`nX  
} C,VvbB  
else sTw+.m{F  
{ ^_\%?K_u  
for(int i=0;i<nStartPos.length;i++) :HkXsZ  
{ "*ww>0[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Qe
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} ,d$D0w  
for(int i=0;i<nEndPos.length-1;i++) #.@-ng6C  
{ \U.js-  
nEndPos = nStartPos[i+1]; M&` b\la  
} A/88WC$v  
nEndPos[nEndPos.length-1] = nFileLength; 9G^gI}bY  
} ZMO ym=  
} WGHf?G/s  
40HhMTZ0-  
#;/ob-  
//启动子线程 1EA#c>I$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d
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for(int i=0;i<nStartPos.length;i++) #N;McF;W  
{ R0YWe  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K#xL-   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /-
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nStartPos,nEndPos,i); e$o
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `j!XWh*$  
fileSplitterFetch.start(); % !Ih=DZ  
} w[OUGn'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R$i-
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); )8;At'q}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~9n30j%]s  
nEndPos = " + nFileLength); N."x@mV  
// fileSplitterFetch[nPos.length-1].start(); d8K|uEHVz  
z8cefD9F  
40}7O<9*  
//等待子线程结束 4O
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//int count = 0; #|=Q5"wU  
//是否结束while循环 /cZTj!M  
boolean breakWhile = false; hRZYvZ3  
8~y&"  \  
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while(!bStop) cc0Tb  
{ 'PWA  
write_nPos(); @S1Z"%S  
Utility.sleep(500); NiD_v  
breakWhile = true; 'zOB!QqA`v  
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for(int i=0;i<nStartPos.length;i++) ZP'0=  
{ 2])e}&i  
if(!fileSplitterFetch.bDownOver) Sm;@MI<@/  
{ 8^sh@j2L  
breakWhile = false; 17-B'Gl!<%  
break; ; *\xdg{d  
} y%O^Zm1  
} ;.=]Ar}  
if(breakWhile) n0g8B  
break; gF
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@D>qo=KPM  
I>{o]^xw-D  
//count++; U7HfDDh  
//if(count>4) +QP(ATdM  
// siteStop(); oSIP{lfp2Q  
} EVP{7}K1  
J vq)%t8q>  
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System.err.println("文件下载结束！"); JJ9R, 8n6  
}
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catch(Exception e){e.printStackTrace ();} WjOP2CVv|  
} $$i Gs6az  
#n]K$k>  
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//获得文件长度 TjHt:%7.  
public long getFileSize() j8c5_&  
{ }{)Rnb@ >  
int nFileLength = -1; nDyA][  
try{ hbEqb{#}@  
URL url = new URL(siteInfoBean.getSSiteURL()); #4<=Ira5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !*S,S{T8  
httpConnection.setRequestProperty("User-Agent","NetFox"); snYeo?|b  
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int responseCode=httpConnection.getResponseCode();  \>||  
if(responseCode>=400) 2_}oOt?qiM  
{ 3)I]bui  
processErrorCode(responseCode); @saK:z  
return -2; //-2 represent access is error @WNqD*)1  
} ~tn$AtK  
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String sHeader; ubRhJ~XB  
(2UA,  
}B_?7+  
for(int i=1;;i++) >~_z#2PA  
{ `@ny!S|1/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Kg`P@  
//Utility.log(in.readLine()); X,bhX/h  
sHeader=httpConnection.getHeaderFieldKey(i); Lp/'-Y_  
if(sHeader!=null) ;tQ(l%!  
{ ;YSe:m*  
if(sHeader.equals("Content-Length")) T}
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{ @Ne&%F?^Z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); wY ??#pS  
break; X&IT s  
} ;"Aj80  
} #<X4RJ  
else 'T$Cw\F&  
break; T?RN} @D  
} -xbs'[  
} rT\~VJ>+i  
catch(IOException e){e.printStackTrace ();} mE_%  
catch(Exception e){e.printStackTrace ();} h=\1ZQKC)  
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Utility.log(nFileLength); :W6'G@ p  
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return nFileLength; \GQRpJ#h1  
} WP?]"H  
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2vU-9p {  
//保存下载信息（文件指针位置） Pm%5c\ef  
private void write_nPos() P(DEf(  
{ ![$`Ivro`  
try{ [+QyKyhTO  
output = new DataOutputStream(new FileOutputStream(tmpFile)); `wZ  
output.writeInt(nStartPos.length); y5F"JjQAa  
for(int i=0;i<nStartPos.length;i++) Hpa6;eT  
{ w,up`W7,  
// output.writeLong(nPos); K\xnQeS<W  
output.writeLong(fileSplitterFetch.nStartPos); QT zN  
output.writeLong(fileSplitterFetch.nEndPos); m.!LL]]  
} <VSB!:ew  
output.close(); TGU7o:2  
} J9OL>!J  
catch(IOException e){e.printStackTrace ();} j Neb*dPoK  
catch(Exception e){e.printStackTrace ();}
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} V)`A,7X  
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,|A6l?iV  
//读取保存的下载信息（文件指针位置） ?@Q0;LG  
private void read_nPos() <T;V9(66  
{ *C0a,G4  
try{ 8EMBqhl  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); cvo+{u$s  
int nCount = input.readInt(); K F_Uu  
nStartPos = new long[nCount]; x;`Gn_  
nEndPos = new long[nCount]; )+|wrK:*v  
for(int i=0;i<nStartPos.length;i++) =+b>d\7xG  
{ S>r}3,]S  
nStartPos = input.readLong(); YtKT3u:x  
nEndPos = input.readLong(); pUS:HJk|  
} 4`mf^Kf  
input.close(); Ph%ylS/T{  
} {[`(o 0@(  
catch(IOException e){e.printStackTrace ();} (+;D~iN`k  
catch(Exception e){e.printStackTrace ();} [[]yQ "  
} -G@uB_Cs  
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private void processErrorCode(int nErrorCode) r]&sXKDc  
{ @*~yVV!5  
System.err.println("Error Code : " + nErrorCode); A
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} J[r_ag  
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//停止文件下载 ,YjjL  
public void siteStop() (gPB@hAv  
{ `xHpL8i$5  
bStop = true; XR9kxTuk  
for(int i=0;i<nStartPos.length;i++) )B+o F7  
fileSplitterFetch.splitterStop(); $GU s\  
("PZ!z1m1  
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} R-dv$z0  
} G7|d$!%  
//负责部分文件的抓取 rqiH!R  
**FileSplitterFetch.java rp dv{CUp7  
*/ rPBsr<k#5  
package NetFox; );AtFP0Y  
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jD"nEp-  
import java.io.*; p7Zeudmj  
import java.net.*; llR5qq=t  
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public class FileSplitterFetch extends Thread { V`LE 'E  
j^8HTa0Cy|  
sC[#R.eq  
String sURL; //File URL sk<S`J,M/_  
long nStartPos; //File Snippet Start Position 88X]Uw(+  
long nEndPos; //File Snippet End Position a@&qdp  
int nThreadID; //Thread's ID TCzlu#w  
boolean bDownOver = false; //Downing is over :Zkjtr.\  
boolean bStop = false; //Stop identical UJDI[`2  
FileAccessI fileAccessI = null; //File Access interface ==?%
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m<z?6VC  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException K$D+TI)  
{ [h-NX  
this.sURL = sURL; E#Ue9J  
this.nStartPos = nStart; 1|-C(UW>  
this.nEndPos = nEnd; -c1-vGW/  
nThreadID = id; 17c`c.yP  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ujE~#b}X  
} sx;/xIU|  
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public void run() ~N; dX[@BT  
{ Fw(  
while(nStartPos < nEndPos && !bStop) ]AM*9!  
{ ws,?I
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try{ Gs|a$^V|o  
URL url = new URL(sURL); % q!i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]e5aHpgR=  
httpConnection.setRequestProperty("User-Agent","NetFox"); @oj_E0i3  
String sProperty = "bytes="+nStartPos+"-"; F?MVQ!K*  
httpConnection.setRequestProperty("RANGE",sProperty); %La/E#  
Utility.log(sProperty); `|"o\Bg<  
:jkPV%!~  
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InputStream input = httpConnection.getInputStream(); @ YWuW
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//logResponseHead(httpConnection); C"`\[F`.k  
il{x?#Wrb  
/8`9SS  
byte[] b = new byte[1024]; Sh-B!  
int nRead; P|?nx"c  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qFDy)4H)  
{ #')]~Xa  
nStartPos += fileAccessI.write(b,0,nRead); pX>wMc+  
//if(nThreadID == 1) w^HI lA  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w""u]b%:r  
} Ktzn)7-  
7KRNTnd  
5oYeUy>N  
Utility.log("Thread " + nThreadID + " is over!"); X2| Z!  
bDownOver = true; Bs`='w%7  
//nPos = fileAccessI.write (b,0,nRead); oz:J.<j24Z  
} d3?gh[$  
catch(Exception e){e.printStackTrace ();} :mCGY9d4L  
} +|+fDQI  
} 0L"uU3  
yJqDB$0  
:18}$  
//打印回应的头信息 hZUS#75M5  
public void logResponseHead(HttpURLConnection con) jL4"FTcE]3  
{ RN1KM  
for(int i=1;;i++) e*( _Cvxp  
{ =yqg,w&Q  
String header=con.getHeaderFieldKey(i); jamai
8  
if(header!=null) }l]r-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); HP3%CB  
Utility.log(header+" : "+con.getHeaderField(header)); <>-gQ9  
else M_7
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break; Ud>hDOJ3  
} hN1[*cF  
} n],cs  
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p{r{}i
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public void splitterStop() R~TG5^(  
{ ko!aX;K  
bStop = true; ^H<VH  
} A"+t[0$.  
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} R5uz<  
>i61+uzEd+  
55>+%@$,a  
/* c No)LF  
**FileAccess.java ,<OS:]  
*//文件访问(定位，写) Wk-.dJ  
package NetFox; ND 8;1+3  
import java.io.*; b_~KtMO  
'e x/IqbK  
=<=[E:B  
public class FileAccessI implements Serializable{ T z+Y_  
MI8c>5?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 E*9W'e~=  
RandomAccessFile oSavedFile; =`gFwH<   
long nPos; V-i:t,*lk(  
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#?\|)y4i  
public FileAccessI() throws IOException a[lx&CHgI  
{ _@|_`5W  
this("",0); OW> >6zM  
} iqXsDgkr  
tjm@+xs  
FW<YN;  
public FileAccessI(String sName,long nPos) throws IOException DshRH>7s8  
{ E@="n<uS  
oSavedFile = new RandomAccessFile(sName,"rw"); F
EA/}*2F  
this.nPos = nPos; <@@@Pl!~  
oSavedFile.seek(nPos); +w@/$datI  
} .M\0+,%/  
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=&U7:u  
public synchronized int write(byte[] b,int nStart,int nLen) N9f;X{  
{ hJ V*  
int n = -1; <jVk}gi)Jp  
try{ k1FG$1.  
oSavedFile.write(b,nStart,nLen); ~BI! l  
n = nLen; B"RZpx  
} iF+
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catch(IOException e) 1 7hXg"B  
{ X^0jS  
e.printStackTrace (); D4GXZX8K  
} jBd9 $`  
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return n; !P_'n  
} <{1 3Nd'o  
n] n3/wpO  
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} b@[5xv\J  
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TUO#6  
/* Zxv{qbF
 
**SiteInfoBean.java *_yp]z"  
*/ h"Q&E'0d  
package NetFox; S#7.
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SRk-3:  
X_I.
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public class SiteInfoBean { #+P)X_i`  
?DJ,YY9P  
( e(<4-&  
private String sSiteURL; //Site's URL }*0*8~Q'5  
private String sFilePath; //Saved File's Path Yr+ghl
/ V  
private String sFileName; //Saved File's Name +wr 5&  
private int nSplitter; //Count of Splited Downloading File 9DmQ  
RFm9dHI27  
D
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public SiteInfoBean() gLv";"4S  
{//nSplitter的缺省值为5 .J|"bs9  
//default value of nSplitter is 5 ^`!EpO>k9  
this("","","",5); j,JGs[A  
} DcLx[C  
C[(Exe  
`L}Irt}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N+ R/ti  
{ 6~Xe$fP(  
sSiteURL= sURL; ?x &"EhA>  
sFilePath = sPath; \LW '6 pQ_  
sFileName = sName; [kq+a]q  
this.nSplitter = nSpiltter; uH!;4@uI  
s|&2QG0'7  
mh`VZQ@  
} v~>4c<eG  
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public String getSSiteURL() *gzX=*;x+?  
{ 7":0CU%%  
return sSiteURL; 7J2i /m  
} c=HL 6v<
 
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public void setSSiteURL(String value) G@QZmuj&KH  
{ /F 1mYq~  
sSiteURL = value; }mw31=2bD  
} 3AD^B\<gB  
T
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#| Et9  
public String getSFilePath() w_i$/`i+  
{ 6*2z^P9FRj  
return sFilePath; I6FglVQ6  
} N5[fwz w  
eq\{*r"DCK  
"VcG3.  
public void setSFilePath(String value) vg1p{^N!  
{ E8Wgm 8  
sFilePath = value; )f0t"l
k  
} aOj5b>>  
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public String getSFileName() 4o2C=?@(  
{ &sQtS  
return sFileName; `W[oLQ  
} ]7^YPFc+  
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BY$%gIB6>  
public void setSFileName(String value) R('44v5JQp  
{ PTvP;  
sFileName = value; |nj%G<  
} <H~ (iQ  
vf(\?Js,  
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public int getNSplitter() `riK[@  
{ ( UV8M\  
return nSplitter; s?5(E}  
} TlZ|E '_C  

\
^3\_T&6  
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public void setNSplitter(int nCount) mOyBSOad4  
{ R28h%KN  
nSplitter = nCount; BfF$  
} gKS0!U  
} lG;sDR|)(  
nMXSpX>!|  
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/* ]pr;ME<M{  
**Utility.java P$D1kcCw  
*/ H6*d#!  
package NetFox; C sn"sf  
i3>7R'q>  
qGgT<Rd~1  
public class Utility { Z
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e?G] fz  
?+b )=Z  
public Utility() g(MeCoCc  
{ 6P!M+PO  
mg*[,_3q33  
ueYZM<],  
} KaHjL&!  
Y9 ,KOs  
//线程睡眠 vh+IhGi  
public static void sleep(int nSecond) T.aY{Y  
{ h5ST`jZ  
try{ aBT|Q@Y.  
Thread.sleep(nSecond); \=4[v-3H  
} p}}o#a~V),  
catch(Exception e) icHc!m?  
{ 4RNB\D
 
e.printStackTrace (); (~N&ov  
} Yt
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} a!P?RbW  
N/mTG2'<  
//日志 Cjsy1gA  
public static void log(String sMsg) O%y.  
{ =g$%.  
System.err.println(sMsg); 9#.nNv*z3  
} a%sr*`  
W)?B{\  
hO@'WoniW  
public static void log(int sMsg) X)xQKkL0  
{ Y:/z)"u,C  
System.err.println(sMsg); SV}I+O_w  
} W :jC2,s!m  
} WeE>4>^  
k 0z2)
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/* ZPY#<^WOzr  
**TestMethod.java _CBG?  
*/ [L"(flY(E  
package NetFox; SI)u@3hl&w  
HkD6aJ:kA!  
}i./,  
public class TestMethod { frk(2C8T  
$+)SW{7  
[F/>pL5U$  
public TestMethod() gEMxK2MNXj  
{ ///xx/weblogic60b2_win.exe {?17Zth  
try{ :03w k)  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); a8FC#kfq  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); kb]PWOz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `[w:l[i  
fileFetch.start(); A$Mmnu%  
} 8/x@
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catch(Exception e){e.printStackTrace ();} S.aSNH<  
r'uD|T H  
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} YgCJ s;  
0$%:zHi5g  
dQQh$*IL?{  
public static void main(String[] args) (2Z-NVU#  
{ VlXUrJ9&  
new TestMethod(); fa;\4#  
} %,E\8{I+  
} PW x9CT  
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