http断点续传简单实现（java)

/* h#7p&F  
**SiteFileFetch.java RO+N>Wkt  
*/ Gm2q`ki  
package NetFox;  &@h(6  
import java.io.*; 2/m4|  
import java.net.*; nkn4VA?"  
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public class SiteFileFetch extends Thread { yz7X7mAo  
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SiteInfoBean siteInfoBean = null; //文件信息Bean $\A=J  
long[] nStartPos; //开始位置 ]
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long[] nEndPos; //结束位置 Uo
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 gONybz6]  
long nFileLength; //文件长度 \7U'p:h=U  
boolean bFirst = true; //是否第一次取文件 E6zSMl5b  
boolean bStop = false; //停止标志 (764-iv(  
File tmpFile; //文件下载的临时信息 ]5Mq^@mD'  
DataOutputStream output; //输出到文件的输出流 g<(\#F}/  
{\62c;.  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） M!)~h<YL  
public SiteFileFetch(SiteInfoBean bean) throws IOException n/Fx2QC{  
{ O=E?m=FR"  
siteInfoBean = bean; '`nf7

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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); k ^(RSu<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ly~tB LH}  
if(tmpFile.exists ()) _ ,~D]JYE  
{
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bFirst = false; T1[B*RwC  
read_nPos(); F9PXQD(  
} o@4
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else FX,kmre3  
{ 6[~_;0  
nStartPos = new long[bean.getNSplitter()]; &~{0@/
 
nEndPos = new long[bean.getNSplitter()]; p%ZOLoc)Y  
} fuao*L]  
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} LzGS
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public void run()  Xn=  
{ _Qd CV`  
//获得文件长度 /k^!hI"4c  
//分割文件 NSkIzaNY  
//实例FileSplitterFetch 7Q>bJ Ek7  
//启动FileSplitterFetch线程 bSgdVP-  
//等待子线程返回  ow2tfylV  
try{ 8'|
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if(bFirst) ~.&PQE$DF  
{ L<W2a(  
nFileLength = getFileSize(); #,B+&SK{  
if(nFileLength == -1) i)=dp!Bx^  
{ aaRc?b'/  
System.err.println("File Length is not known!"); 1)v]<Ga~%1  
} RcpKv;=iB  
else if(nFileLength == -2) |{V@t1`  
{ PQvpJFpb~h  
System.err.println("File is not access!"); _>RTefL5  
} Vqp3'=No  
else mTgsvC  
{ *|B
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for(int i=0;i<nStartPos.length;i++) u{8:VX  
{ bvF-F$n%F  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "|nh=!L  
} `"h[Xb#A`b  
for(int i=0;i<nEndPos.length-1;i++) s_#6^_  
{ 'bn$"A"{o  
nEndPos = nStartPos[i+1]; 'Rq2x-72}  
} Lhmb=
@  
nEndPos[nEndPos.length-1] = nFileLength; i{biQ|,.sL  
} &`I7
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} ^,{ r[}  
T7LO}(I.&  
2P,{`O1]  
//启动子线程 BI6]{ZC"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Z3O_K  
for(int i=0;i<nStartPos.length;i++) WwF2Ry^a  
{ RYZM_@5$t  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Nq"J[l*+g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^*'fDP*  
nStartPos,nEndPos,i); 2bAH)=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H8V@KB  
fileSplitterFetch.start(); |Ng}ZLBM  
} J936o3F_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g=e~YM85  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); G'{*guYU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3XcFBFE  
nEndPos = " + nFileLength); g_;4@jwTP"  
// fileSplitterFetch[nPos.length-1].start(); gt\*9P   
bkS-[rW  
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//等待子线程结束 )-^[;:B\k"  
//int count = 0; Xq%ijo  
//是否结束while循环 4uE|$  
boolean breakWhile = false; `]4tJJy$  
'J8Ga<s7C  
qnJs,"sn  
while(!bStop) IVso/!   
{ {sF;R.P&r  
write_nPos(); 46D_K  
Utility.sleep(500); hH_\C.bL  
breakWhile = true; *T2kxN,Ik  
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for(int i=0;i<nStartPos.length;i++) 51 "v`O+  
{ ?*:BgaR_  
if(!fileSplitterFetch.bDownOver) 1pM>-"a8j  
{ d,E2l~s  
breakWhile = false; ZY*_x)h+#7  
break; I]Ws
  
} juB/?'$~  
} WO=P~F<  
if(breakWhile) og`g]Z<I  
break; R'$1,ie  
z-m:l;  
}*c[}VLN  
//count++; ?i$MinK  
//if(count>4) \RmU6(;IQ  
// siteStop(); /! M%9gu  
} @5{h+^  
R<Ct{f!  
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System.err.println("文件下载结束！"); &{S@v9~IT  
} $?y\3GX  
catch(Exception e){e.printStackTrace ();} wp<f{^ et  
} +<'>~lDg  
qU^`fIa  
W.>}5uVl6  
//获得文件长度 n!L}4Nmp  
public long getFileSize() K<p
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{ KNSMx<GP  
int nFileLength = -1; KP CZiu7  
try{ LT:8/&\  
URL url = new URL(siteInfoBean.getSSiteURL()); */j[n$K>~`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |z`AIScT  
httpConnection.setRequestProperty("User-Agent","NetFox"); `FByME  
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int responseCode=httpConnection.getResponseCode(); e
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if(responseCode>=400) !wIrI/
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{ 8[x{]l[  
processErrorCode(responseCode); s\.\z[1  
return -2; //-2 represent access is error j5m]zh5\J=  
} Z8o8>C\d9/  
8:k-]+#o  
-|GX]jx(Y  
String sHeader; 1(qL),F;  
):nC&M\W~  
(4IH%Ez){  
for(int i=1;;i++) `FmRoMW9+  
{ nQd~i0`vB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); R!2E`^{Wl  
//Utility.log(in.readLine()); -fDW>]_  
sHeader=httpConnection.getHeaderFieldKey(i); jUB`=d|  
if(sHeader!=null) h-5] nL3  
{ !$#8Z".{v{  
if(sHeader.equals("Content-Length")) d8VFa'|  
{ -Hg,:re2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m,r>E%;Cj  
break; 1  Lz  
} ,ZvlKN  
} hv)d  
else BHDd^bd  
break; {#&j
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} 6bUcrw/# p  
} cL:hjr"  
catch(IOException e){e.printStackTrace ();} yi,Xs|%.  
catch(Exception e){e.printStackTrace ();} (w?W
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Utility.log(nFileLength); .p-T >  
)`}4rD^b  
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return nFileLength; @<B$LJ|jdG  
} w>&g'  
XVYj X  
g>-u9%aa  
//保存下载信息（文件指针位置） 47^
7S=  
private void write_nPos() |/;X-+f8  
{ @vvGhJ1m`  
try{ ;b^"b{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :tX,`G  
output.writeInt(nStartPos.length); A'T: \Wl  
for(int i=0;i<nStartPos.length;i++) pt~b=+bBm  
{ lVS.XQ2<  
// output.writeLong(nPos); J;Veza  
output.writeLong(fileSplitterFetch.nStartPos); #)( D_*  
output.writeLong(fileSplitterFetch.nEndPos); 9^^:Y3j  
} {@>6E8)H5  
output.close(); >\Ml\CyL  
} a<&GsDw  
catch(IOException e){e.printStackTrace ();} W_h!Pu
j_  
catch(Exception e){e.printStackTrace ();} yQquGu  
} L+NrU+:=C  
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//读取保存的下载信息（文件指针位置） ,\D*=5  
private void read_nPos() "i;"  
{ p$l'y""i  
try{ e%JH q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 01vKx)f  
int nCount = input.readInt(); <CGJ:% AY  
nStartPos = new long[nCount]; *."50o=T  
nEndPos = new long[nCount]; "j?\Ze*  
for(int i=0;i<nStartPos.length;i++) Ll0"<G2t  
{ M]A!jWtE  
nStartPos = input.readLong(); br4 %(w(d  
nEndPos = input.readLong(); L] !M1\  
} &9\8IR>  
input.close(); 9M1UkS$`@  
} b1-'q^M  
catch(IOException e){e.printStackTrace ();} 6}GcMhU<r  
catch(Exception e){e.printStackTrace ();} ?eri6D,86w  
} %q_b\K  
T:!Re*=JJ  
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private void processErrorCode(int nErrorCode) '+E\-X  
{ z*G(AcS)  
System.err.println("Error Code : " + nErrorCode); R![4|
FR  
} d@>1m:p  
K)9+3(?  
_4~q&?}V  
//停止文件下载 ]TIBy "3  
public void siteStop() [.c'22R6  
{ >IE`, fe  
bStop = true; ::2(pgH  
for(int i=0;i<nStartPos.length;i++) #wfb-`,5&9  
fileSplitterFetch.splitterStop(); ~=Q Tv8  
n+:}pD  
;B6m;[M+  
}
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} _e94  
//负责部分文件的抓取 qfsu# R  
**FileSplitterFetch.java G~KYFNHr  
*/ +z?SKc  
package NetFox; B dKD%CJ[  
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<}bF49z  
import java.io.*; 9y(491"o  
import java.net.*; -9~WtTaV.H  
j|2s./!Qg  
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public class FileSplitterFetch extends Thread { p5JRG2zt  
qotWWe#  
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String sURL; //File URL D=:O^<  
long nStartPos; //File Snippet Start Position *g!7P
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long nEndPos; //File Snippet End Position #D|n6[Y'.t  
int nThreadID; //Thread's ID ?
<6yKxn  
boolean bDownOver = false; //Downing is over .+$ox-EK8  
boolean bStop = false; //Stop identical F7IZ;4cp  
FileAccessI fileAccessI = null; //File Access interface 'rDai[  
-mY,nMDb  
^s_7-p])(  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 
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{ _FtsO<p)"  
this.sURL = sURL; V3c7F4\  
this.nStartPos = nStart; W?X3 :1c9:  
this.nEndPos = nEnd; !?5YXI,  
nThreadID = id; }B@44HdY  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 G*%:"qleT$  
} !"<~n-$B  
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'e:(61_  
public void run() ]oxi~TwY^  
{ ]3]=RuQK2  
while(nStartPos < nEndPos && !bStop) /MZ^;XG  
{ *=zv:!  
jH?!\F2)+  
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try{ yoG*c%3V?  
URL url = new URL(sURL); IQeiT[TF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); HMmB90P`  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,)ZI&BL5  
String sProperty = "bytes="+nStartPos+"-"; DhD^w;f]  
httpConnection.setRequestProperty("RANGE",sProperty); DTvCx6:!  
Utility.log(sProperty); #Fz/}lO  
FwUgMR*xq  
+F+M[ef<ws  
InputStream input = httpConnection.getInputStream(); >)+N$EN  
//logResponseHead(httpConnection); .FC|~Z1T<F  
M< /
 
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byte[] b = new byte[1024]; n50WHlMtt  
int nRead; Go(Td++HS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) lRR A2Kql  
{ v?0F  
nStartPos += fileAccessI.write(b,0,nRead); T{)_vQ  
//if(nThreadID == 1) _$i
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]94`7@  
} -ARks_\  
\3`r/,wY  
2P^x'I  
Utility.log("Thread " + nThreadID + " is over!"); )6(|A$~C+  
bDownOver = true; ~z)JO'Z$  
//nPos = fileAccessI.write (b,0,nRead); H*Tzw,f~ v  
} )+|Y;zC9  
catch(Exception e){e.printStackTrace ();} < n/ 2  
} 
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} Kc,i$FH  
3S" /l
  
l=ZD&uK  
//打印回应的头信息 /36gf  
public void logResponseHead(HttpURLConnection con) kpXxg: c  
{ 1)5$,+~lL  
for(int i=1;;i++) 8OiCldw:HN  
{ Zz"8  
String header=con.getHeaderFieldKey(i); 4w)>}  
if(header!=null) 'q?Y5@s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :
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Utility.log(header+" : "+con.getHeaderField(header)); 0TZB}c#qT  
else .N( X.C  
break; b~r:<
:;  
} [S1 b\f#  
} )ZI#F]  
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%z=:P{0U
Q  
public void splitterStop() *jvP4Nz)k  
{ *<X1M~p$  
bStop = true; 6l[v3l"t  
} +(PUiiP'"v  
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*@p"  
} OF03]2j7<|  
#:By/9}-  
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/* rZ|p{ym  
**FileAccess.java @6|<c  
*//文件访问(定位，写) }79O[&  
package NetFox; .{\eco  
import java.io.*; Vjs'|%P7  
Le:C8^  
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public class FileAccessI implements Serializable{ qB (Pqv  
8["%e#%`$  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]J'TebP=L5  
RandomAccessFile oSavedFile; *asv^aFpS  
long nPos; &R?`QB2/  
zWhj>Za  
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public FileAccessI() throws IOException Zp3-Yo w2  
{ C1e@{>  
this("",0); "3\y~<8%'  
} 51b%uz  
r'j88)^  
`(h
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public FileAccessI(String sName,long nPos) throws IOException Te L&6F$  
{ |(Mxbprz  
oSavedFile = new RandomAccessFile(sName,"rw"); [U/h'A.j  
this.nPos = nPos; h{iuk3G`h6  
oSavedFile.seek(nPos); ^;<d<V}*  
} c0'ryS_Z9  
J)Y`G4l2@  
u+r!;-0i  
public synchronized int write(byte[] b,int nStart,int nLen) )f|`mM4DW!  
{ !e$ZOYe  
int n = -1; Or.u*!od&  
try{ U,#x\[3!Jt  
oSavedFile.write(b,nStart,nLen); '0+~]4&}q  
n = nLen; +4_,, I  
} /]3[|  
catch(IOException e) i,r:R g~  
{ x C&IR*  
e.printStackTrace (); Zh;wQCDj  
} rhbz|Uq  
9
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'~&W'='b;  
return n; 6whPW .  
} jeWv~JA%L|  
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IU"  
} JE-*o"&  

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/* C7ivAh  
**SiteInfoBean.java 8xO   
*/ 'c7nh{F  
package NetFox; U_"!\lI_yg  
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public class SiteInfoBean { H9(?yI@Zr#  
sWo`dZ\6WB  
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private String sSiteURL; //Site's URL "iK= 8  
private String sFilePath; //Saved File's Path 7x6M]1F  
private String sFileName; //Saved File's Name (0NffM1  
private int nSplitter; //Count of Splited Downloading File "5V;~}=S  
Dm}eX:'{  
xUdGSr50  
public SiteInfoBean() x8rg/y  
{//nSplitter的缺省值为5 Rsfb?${0G  
//default value of nSplitter is 5 8<C*D".T$  
this("","","",5); <l5i%?  
} T ?[28|  
skcyLIb  
cuQ!"iH  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) t`H1]`c?  
{ T aS
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sSiteURL= sURL; 9-pt}U  
sFilePath = sPath; `<nxXsLe  
sFileName = sName; G<7M;vRvP  
this.nSplitter = nSpiltter; M^Sa{S*?  
O t)}:oG  
/JS_gr@DK  
} K83'`W^  
i47LX;}  
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public String getSSiteURL() bG]0|  
{ wOf8\s1  
return sSiteURL; 486\a  
} Sh(ys*y>  
rC!O}(4t%$  
*F1TZ_GS  
public void setSSiteURL(String value) >8"(go+02  
{ A M[f  
sSiteURL = value; Hl}lxK,]  
} oT\K P  
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public String getSFilePath() R:f!ywj%  
{ zH~P-MqC  
return sFilePath; 2FuV%\p  
} OpaRQ=  
[@9S-$Xa  
#;!@Pf  
public void setSFilePath(String value) RK.lzVaY  
{ 9~`#aQG T  
sFilePath = value; wKi#5k2  
} 1av#u:jy~>  
}6^5mhsL  
C')KZ|JIC  
public String getSFileName() L|WrdT D;  
{ 9^DAlY,x.  
return sFileName; t#(=$  
} EHq;eF  
)w4U]inJ$"  
3!F^vZ.  
public void setSFileName(String value) L
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{ K/B$1+O  
sFileName = value; F&uiI;+zJ  
} <D:q4t  
PeIi@0vA  
w=?nD6Xhz  
public int getNSplitter()
4tUoK[p  
{ 1o/(fy  
return nSplitter; sg-^ oy*^  
} 93D
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G*EF_N.G0  
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public void setNSplitter(int nCount) >lM/\HO2  
{ m4h)Wq  
nSplitter = nCount; 075IW"p'  
} H(K!{k  
} v+xrnz  
z[ ;n2o|s  
k(tB+k!vH\  
/* ~M* UMF^  
**Utility.java a0]GQyIG  
*/ 03)irq%l;  
package NetFox; aC=2v7*  
!nL94:8U  
>pZ_  
public class Utility { <(TAA15Xol  
jTqJ(M}L  
c{to9Lk.#  
public Utility() %!-t7K^mFq  
{ K)x6F15r  
q("l?'  
o$->|k  
} ^y ', l  
'HfI~wN  
//线程睡眠 SF:{
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public static void sleep(int nSecond) D->E&#  
{ _"D J|j  
try{ `ba<eT':  
Thread.sleep(nSecond); Vm@VhCsp  
} @>'Wiq!  
catch(Exception e) ?5Z-w  
{ s$9ow<oi]  
e.printStackTrace (); yTbtS-  
} ?vD<_5K;I  
} liB~vdqj  
4 }_}3.  
//日志 3- d"-'k  
public static void log(String sMsg) FB+nN5D/  
{ "/^kFsvp  
System.err.println(sMsg); j _E(h.  
} KVoi>?a   
c}=[r1M*  
{az LtTh  
public static void log(int sMsg) WpI5C,3Z!l  
{ R 'mlKe x  
System.err.println(sMsg); A}pe>ja  
} b1e)w?n  
} v"sU87+  
}LIf]YK  

zS?}3#g0u  
/* .b*-GWx  
**TestMethod.java hA~5,K0b  
*/ ER]C;DYX  
package NetFox; TSL/zTLDJ  
c3Ig4n0Y>  
5=MM^$QG  
public class TestMethod { %s%e5hU  
).C>>1ZC  
Zr\G=0`  
public TestMethod() kA4kQ}q  
{ ///xx/weblogic60b2_win.exe EX3;|z@5;  
try{ oB}rd9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); i6h0_q
8 >  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ORV'dr  
SiteFileFetch fileFetch = new SiteFileFetch(bean); a)L=+Z  
fileFetch.start(); ##NowO  
} !.={p8X-x  
catch(Exception e){e.printStackTrace ();} ws}>swR,  
BA0.B0+"  
kmL~H1qd  
} +@oo8io  
7\;gd4Ua1  
laFF/g;sRC  
public static void main(String[] args) G Q+g.{c  
{ T/l2B1  
new TestMethod(); .We"j_ }  
} p>]2o\["  
} 9ev"BO  
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