http断点续传简单实现（java)

/* 8\AyKw  
**SiteFileFetch.java tom1u>1n  
*/ gv
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package NetFox; d
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import java.io.*; QbN7sg~~  
import java.net.*; slQxz;t  
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public class SiteFileFetch extends Thread { k=nN#SMn  

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SiteInfoBean siteInfoBean = null; //文件信息Bean NcuZw?  
long[] nStartPos; //开始位置 #mK/xbW  
long[] nEndPos; //结束位置 I[x+7Y0k9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %2S+G?$M?  
long nFileLength; //文件长度 }L!%^siG_  
boolean bFirst = true; //是否第一次取文件 vp[;rDsIJ$  
boolean bStop = false; //停止标志 %',bCd{QW  
File tmpFile; //文件下载的临时信息 A"Prgf eT  
DataOutputStream output; //输出到文件的输出流 Fm{/&U^  
@|=JXSr!KY  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） x)]_]_vX  
public SiteFileFetch(SiteInfoBean bean) throws IOException ytmFe!  
{ !1X^lFf;~  
siteInfoBean = bean; z PW[GkD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <P%<EgOE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); FX->_}kL=  
if(tmpFile.exists ()) >qqI6@h]c  
{ V[Z^Z  
bFirst = false; !vrduOB  
read_nPos();
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} 7])cu>/  
else
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{ Au=9<WB%H  
nStartPos = new long[bean.getNSplitter()]; Q#h*C ZT  
nEndPos = new long[bean.getNSplitter()]; zXEu3h  
} MF41q%9p  
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} bV3
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public void run() Uo~-^w}  
{ ytDp 4x<W)  
//获得文件长度 76} a  
//分割文件 `R\nw)xq  
//实例FileSplitterFetch Miw*L;u@W  
//启动FileSplitterFetch线程 &*
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//等待子线程返回 ycPGv.6  
try{ [9lfR5=Xw[  
if(bFirst) *l-f">?|  
{ &A1~x!`  
nFileLength = getFileSize(); v/s6!3pnl  
if(nFileLength == -1) i3SrsVSG  
{ {9,!XiF.:  
System.err.println("File Length is not known!"); )-u0n],  
} AB:JXMyK  
else if(nFileLength == -2) MS=
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{ p'fD:M:  
System.err.println("File is not access!"); J% b`*?A  
} #Bih=A #  
else k$NNpv&;d  
{ 3= q,k<=L  
for(int i=0;i<nStartPos.length;i++) 6^Q/D7U;s  
{ rgK:ujzW!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `"-ln'nw  
} h(>eHP  
for(int i=0;i<nEndPos.length-1;i++) ^z^zsNx  
{ }5nVZ;  
nEndPos = nStartPos[i+1]; j-CSf(qIj  
} v
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nEndPos[nEndPos.length-1] = nFileLength; ^'Z?BK  
} }
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} C3hQT8~  
4[.DQ#r  
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//启动子线程 2C&G'@>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; AWG;G+  
for(int i=0;i<nStartPos.length;i++) O'i!}$=g  
{ -,Oq=w*EV  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), tx9;8K3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), X9S`#N  
nStartPos,nEndPos,i); 2d:5~fEJp  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `zw^ WbCO{  
fileSplitterFetch.start(); Ocp`6Fj  
} oZ!1^o3V  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P\nz;}nv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); h;lg^zlTb  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", +%'!+r l  
nEndPos = " + nFileLength); en?J#fz  
// fileSplitterFetch[nPos.length-1].start(); c?/R=/H  
|n/qJIE6  
pVa9g)+z}  
//等待子线程结束 ALO0yc  
//int count = 0; t!285J8tn  
//是否结束while循环 "B34+fOur  
boolean breakWhile = false; o]jPG  
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while(!bStop) &%\H170S  
{ NU <K+k  
write_nPos(); O'L9 s>B  
Utility.sleep(500); |Vj@;+/j  
breakWhile = true; Al0ls  
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for(int i=0;i<nStartPos.length;i++) x[dR5  
{ v&]k8Hc-  
if(!fileSplitterFetch.bDownOver) Hdxon@,+cd  
{ Fo:60)
Lr  
breakWhile = false; N0POyd/rL  
break; H-g CY|W  
} z=[?&X]O9b  
} 5?=haGn  
if(breakWhile) t"Tv(W?_  
break; B_3:.1>"BM  
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O+w82!<:  
//count++; Q8GI;`Rb  
//if(count>4) 6M^NZ0~J  
// siteStop(); q,%lG$0v  
} V\
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>gSiH#>  
System.err.println("文件下载结束！"); p2I
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} VsjE*AJpe  
catch(Exception e){e.printStackTrace ();} bSv
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} wOLA8UYW  
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&  
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//获得文件长度 - xE%`X  
public long getFileSize() 7mBH#Q)  
{ g=)OcTd#  
int nFileLength = -1; ]Dd}^khv  
try{ ur@"wcl"V  
URL url = new URL(siteInfoBean.getSSiteURL()); U'oFW@Y;h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); UfxYD  
httpConnection.setRequestProperty("User-Agent","NetFox"); !+H)N  
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int responseCode=httpConnection.getResponseCode(); WFm\ bZ.  
if(responseCode>=400) kes GwMr"e  
{ {4^NZTjd@  
processErrorCode(responseCode); , #nYHD  
return -2; //-2 represent access is error F~Sw-b kSf  
} #KgDOCQH  
3IyNnm=u  
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String sHeader; ZFFK
v  
O =gv2e  
]*v[6 +  
for(int i=1;;i++) o$rA;^2X  
{ Y=$PsDh!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); DOB#PI[/  
//Utility.log(in.readLine()); uN*Ynf(:-  
sHeader=httpConnection.getHeaderFieldKey(i); !eP)"YWI3  
if(sHeader!=null) $_Kcm"oj  
{ Yj{-|2YzL  
if(sHeader.equals("Content-Length")) t#N@0kIX.  
{ UpFm3gKF  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); w,!IvDCAw  
break; Y2d(HD@  
} m4_ZGjmJM  
} sg9  
else z~($ "  
break; g/(3D  
} q445$ndCT  
} Z!foD^&R  
catch(IOException e){e.printStackTrace ();} aESlbH  
catch(Exception e){e.printStackTrace ();} 2kkqPBc_  
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Utility.log(nFileLength); 7wz9x8\t  
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return nFileLength; wmDO^}>ZP  
} 59#o+qo4  
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:x[SV^fw[  
//保存下载信息（文件指针位置） BIY"{"hJ  
private void write_nPos() `_+%  
{ pQCocy  
try{ PR3&LI;B*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); =OamN7V=  
output.writeInt(nStartPos.length); &B?*|M`)k  
for(int i=0;i<nStartPos.length;i++) F&u)wI'  
{ wB+X@AA  
// output.writeLong(nPos); mkuK$Mj  
output.writeLong(fileSplitterFetch.nStartPos); N!%[.3o\K  
output.writeLong(fileSplitterFetch.nEndPos); n`.JI(|  
} e5$S2o~JF  
output.close(); C0gO^A.d  
} F S!D  
catch(IOException e){e.printStackTrace ();} *nx$r[Mqj  
catch(Exception e){e.printStackTrace ();} V{C{y5  
} g@|2z
  
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//读取保存的下载信息（文件指针位置） @bF4'M  
private void read_nPos() -LU%z'  
{ bc]SY =  
try{ fJD+GvV$x  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?)O!(=6%'  
int nCount = input.readInt(); 0)]?@"j  
nStartPos = new long[nCount]; {NUI8AL46A  
nEndPos = new long[nCount]; ksy]t|  
for(int i=0;i<nStartPos.length;i++) k*K.ZS688  
{ uJSzz:\  
nStartPos = input.readLong(); e]*@|e
4b  
nEndPos = input.readLong(); UW'@3#<?  
} cnz+%Y N  
input.close(); '1"vwXJ"  
} v(P5)R,  
catch(IOException e){e.printStackTrace ();} g+]o=@  
catch(Exception e){e.printStackTrace ();} iI Dun Ih  
} ^tY _ q  
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private void processErrorCode(int nErrorCode) LV@tt&|N  
{ x4XCR,-  
System.err.println("Error Code : " + nErrorCode); dLbSvK<(I  
} yYiu
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V*gh"gZ<  
_)ZxD--Qg  
//停止文件下载 ;T :]?5W!  
public void siteStop() pEq }b+-  
{ in7h^6?I  
bStop = true; zuS4N?t`p  
for(int i=0;i<nStartPos.length;i++) B &e'n
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fileSplitterFetch.splitterStop(); +vIsYg*#2M  
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} G=PX'dS  
} .`jYrW-k  
//负责部分文件的抓取 (*Z:ByA  
**FileSplitterFetch.java }=p+X:k=  
*/ GL,( N|  
package NetFox; e=`=7H4P  

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import java.io.*; Hm'aD2k  
import java.net.*; +!mEP>  
=Q#d0Q  
2H/{OQ$  
public class FileSplitterFetch extends Thread { mo"1|Q&  
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#ri;{
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String sURL; //File URL 20/P:;  
long nStartPos; //File Snippet Start Position <>H^:iqn  
long nEndPos; //File Snippet End Position U+,RP$r@  
int nThreadID; //Thread's ID *iVEO  
boolean bDownOver = false; //Downing is over (_=R<:  
boolean bStop = false; //Stop identical {uurLEe?  
FileAccessI fileAccessI = null; //File Access interface 3.6Gh
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'"T9y=9]s  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException M9~6ry-_  
{ V1yP{XT=  
this.sURL = sURL; $|t={s34  
this.nStartPos = nStart; hC?rHw H>  
this.nEndPos = nEnd; $r)NL  
nThreadID = id; n(W&GSj|u9  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [l}H%S   
} ART0o7B  
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public void run() =w/AJ%6  
{ 3_"tds <L  
while(nStartPos < nEndPos && !bStop) 06z+xxCo  
{ aSMoee@!  
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try{ mrBK{@n  
URL url = new URL(sURL); )Em`kle  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j/;wxKW  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]f>0P3O5&  
String sProperty = "bytes="+nStartPos+"-"; pKU(4&BxX  
httpConnection.setRequestProperty("RANGE",sProperty); x@3cZd0j#  
Utility.log(sProperty); EiVVVmm!  
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InputStream input = httpConnection.getInputStream(); (4|R}jv  
//logResponseHead(httpConnection); n`V?n  
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byte[] b = new byte[1024]; -$$mrU  
int nRead; <H$!OPV  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7^syu;DT9Y  
{ t N4-<6  
nStartPos += fileAccessI.write(b,0,nRead); / ;+Mz*  
//if(nThreadID == 1)  U4qk<!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,(&Fb~r]  
} M 5$JBnN  
I&`aGnr^^  
GT\yjrCd  
Utility.log("Thread " + nThreadID + " is over!"); ozKS<<  
bDownOver = true; l,Fn_zO  
//nPos = fileAccessI.write (b,0,nRead); HPg%v|  
} N`~f77G  
catch(Exception e){e.printStackTrace ();} F\^\,hy  
} +ViL"  
} Eu<f  
FY`t7_Y?GV  
+X`&VO6~  
//打印回应的头信息 R{ udV  
public void logResponseHead(HttpURLConnection con) KTBtLUH]*F  
{ 1OV] W f  
for(int i=1;;i++) [SD mdr1T$  
{ hM[3l1o{|  
String header=con.getHeaderFieldKey(i); @$iZ9x6t  
if(header!=null) = 5[%%Lf  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `z$P,^g`  
Utility.log(header+" : "+con.getHeaderField(header)); UyFC\vQ  
else +d7Arg!m  
break; aKE`nA0\B  
} ,U)&ny  
} 3D^cPkX  
qHT73_R  
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public void splitterStop() {+GR/l\!#  
{ EM`'=<)V  
bStop = true; zszmG^W{  
} |6;-P&_n  
||ugb6q[6B  
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} I@\D tQZ
 
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/* RR'sW@  
**FileAccess.java #c":y5:  
*//文件访问(定位，写) 'oH3|  
package NetFox; eoXbZ  
import java.io.*; 9Ofls9]U  
aqWlX0+  
n`@dk_%yI  
public class FileAccessI implements Serializable{ &SNH1b#>E  
i=1crJ:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 EJRkFn8XG'  
RandomAccessFile oSavedFile; qHtIjtt[q  
long nPos; Z}t^i^u  
q"oNFHYPDs  
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public FileAccessI() throws IOException D_1O4/  
{ Ji:<eRx)  
this("",0); :KR KD  
} Go^TTL  
|
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8Lgm50bs  
public FileAccessI(String sName,long nPos) throws IOException fms(_Q:R?  
{ FD&^nJ_{  
oSavedFile = new RandomAccessFile(sName,"rw"); J#ClQ%  
this.nPos = nPos; 0TSB<,9a[  
oSavedFile.seek(nPos); #ti%hm  
} BvH?d]%  
KU*aJl_n,  
4=EA3`l  
public synchronized int write(byte[] b,int nStart,int nLen) 13w(Tf  
{ 4T;<`{]  
int n = -1; e$2P/6k>  
try{ O1)\!=& .  
oSavedFile.write(b,nStart,nLen); vU5}E\Ny  
n = nLen; (CgvI*O  
} bar=^V)  
catch(IOException e) mwyB~,[d+W  
{ A_WaRYG  
e.printStackTrace (); 8UXRM :Z"  
} M_-L#FHX  
ipl,{  
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return n; uv<_.Jq]  
} &xhwOgI#,  
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} iRlpNsN  
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/* Cl!(F6K*  
**SiteInfoBean.java yP>025o't  
*/ T:Ee6I 3l  
package NetFox; H0sTL#/L\  
zH6@v+gb  
2%6 >)|  
public class SiteInfoBean { {7c'%e  
^jUw4Dj~-q  
PgGUs4[  
private String sSiteURL; //Site's URL -zn_d]NV  
private String sFilePath; //Saved File's Path Crg'AB?  
private String sFileName; //Saved File's Name ?w'
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private int nSplitter; //Count of Splited Downloading File Z<^!N)  
>`SeX:  
q<!-Anc  
public SiteInfoBean()
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{//nSplitter的缺省值为5 -W<
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//default value of nSplitter is 5 Gyy4zK  
this("","","",5); _ZFEo< `'  
} o kA<  
"om7 :d  
3)6-S  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) FMI1[|:;  
{ lw[c+F7  
sSiteURL= sURL; FKu8R%9xn%  
sFilePath = sPath; o|xZ?#^h  
sFileName = sName; dFDf/tH  
this.nSplitter = nSpiltter; i}P{{kMJ  
e0(aRN{W  
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} ..+#~3es#y  
Uc'}y!R  
)RvX}y-  
public String getSSiteURL() g#^MO]pY  
{ ~6@`;s`[Y  
return sSiteURL;
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} u4w!SD  
z\A ),;  
S#v
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public void setSSiteURL(String value) uf9&o#  
{ QDV+(  
sSiteURL = value; dXQC}JA  
} F.5fasdX'  
h]
k$K  
%Q0R] Hg  
public String getSFilePath() i!e8-gVMP&  
{ vr'cR2  
return sFilePath; xk% 62W  
} 25-h5$s  
megTp  
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public void setSFilePath(String value) zU+q03l8Ur  
{ '!8-/nlv1  
sFilePath = value; 2M'dTXz  
} I4?oBq  
/\h*v!:  
ktx| c19  
public String getSFileName() D_0Vu/v  
{ /OzoeIt  
return sFileName; =3w;<1 ?'  
} L*[3rqER  
Yg3nT:K_Y&  
OM&GypP6&  
public void setSFileName(String value) 4d4+%5GE  
{ ]2qKc  
sFileName = value; 7<;oz30G!L  
} yG/!K uA  
qrw  
#o4tG  
public int getNSplitter() -dB
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{ ]kTxVe  
return nSplitter; &k%>u[Bo  
} /G'3!S  
A8*zB=C  
CCe>*tdf  
public void setNSplitter(int nCount) |&rCXfC  
{ BB(6[V"SV  
nSplitter = nCount; /}m*|cG/  
} o!":mJy  
} y7fy9jQ 8.  
s{yw1:  
%}VH5s9\  
/* D4[t^G;J  
**Utility.java &tAYF_}  
*/ -R:_o1"  
package NetFox; cS9jGD92  
;ISnI  
T TN!$?G3  
public class Utility { 9"]#.A^Q*  
4$pV;xV  
+)"Rv%.  
public Utility() U\tx{CsSz  
{ l9&k!kF`  
G#GZt\)F  
%NxQb'  
} \>- M&C  
r.\L@Y<  
//线程睡眠 K8&;B)VT>  
public static void sleep(int nSecond) % (y{S
ca  
{ V&s|IoTR  
try{ za@/4z  
Thread.sleep(nSecond); uwSSrT  
} LsuOmB|^  
catch(Exception e) (jDz[b#OPz  
{ }r5yAE  
e.printStackTrace (); MkPQ@s
o  
} P$#:$U@  
} 6
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nO
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//日志 ~$g:  
public static void log(String sMsg) BA]$Fi.Mw  
{ '6 F-%
 
System.err.println(sMsg); =x\`yxsG  
} 7*{f*({  
|2u=3#Jp  
?!U[~Gq  
public static void log(int sMsg) @I`^\oJ  
{ Lr$Mk#'B  
System.err.println(sMsg); {4G/HW28  
} k_=yb^6[U  
} Ptv'.<-  
T+F]hv'  
+ '_t)k^  
/* LnI  
**TestMethod.java 4?'vP'  
*/ k6;bUOo  
package NetFox; M}V!;o<t^  
=Nxkr0])!  
a,c!#iyl3  
public class TestMethod { 9_?
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"+ou!YK+  
VWvSt C  
public TestMethod() LZRg%3.E
 
{ ///xx/weblogic60b2_win.exe xf]K  
try{ \:WWrY8&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #4msBax4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); rR> X<  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  S=(O6+U  
fileFetch.start();
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} ,|({[9jA  
catch(Exception e){e.printStackTrace ();} &3[oM)-V  
I4X9RYB6c  
tNi>TkC}`  
} `x9Eo4(
/  
J, 9NVw$  
##7y|AwK  
public static void main(String[] args) GkIY2PD  
{ rG-T Dm  
new TestMethod(); bP&QFc  
} ixdsz\<  
} 0Ds3wNz  
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