http断点续传简单实现（java)

/* [Cv./hE
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**SiteFileFetch.java y`buY+5l  
*/ ]/1\.<uJId  
package NetFox; ; $80}TY '  
import java.io.*; a24 AmoWx  
import java.net.*; _C?Wk:Y@  
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public class SiteFileFetch extends Thread { *PnO$q@`  
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SiteInfoBean siteInfoBean = null; //文件信息Bean A_oZSUrR  
long[] nStartPos; //开始位置 $xZ ~bE9  
long[] nEndPos; //结束位置 Cn3_D  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  SW#/;|m  
long nFileLength; //文件长度 f; |fS~  
boolean bFirst = true; //是否第一次取文件 zZCRej  
boolean bStop = false; //停止标志 (?\+
  
File tmpFile; //文件下载的临时信息 5\bGCf  
DataOutputStream output; //输出到文件的输出流 g) oOravV  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 6EyPZ{  
public SiteFileFetch(SiteInfoBean bean) throws IOException ZK^cG'^2|  
{ &}k7iaO  
siteInfoBean = bean; &R<aRE:+R  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @!f4>iUy  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 50N4J  
if(tmpFile.exists ()) :Fb>=e  
{ :uo1QavO@,  
bFirst = false; =WY'n l'  
read_nPos(); w_56y8Pd4  
} o?Hfxp0}  
else +;q\7*  
{ ResU5Ce~  
nStartPos = new long[bean.getNSplitter()]; _ Ncbo#G  
nEndPos = new long[bean.getNSplitter()]; sh$-}1 ;  
} %)JEYH7Z  
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} yQ[;y~W  
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public void run() )Fv.eIBY  
{  l!|c_  
//获得文件长度 J2W-l{`r<  
//分割文件 ~:z.Xu5m  
//实例FileSplitterFetch Pqomi!1  
//启动FileSplitterFetch线程 p,fV .5q  
//等待子线程返回 Wm}c-GD  
try{ V^2_]VFj  
if(bFirst) =#G 2}8mQD  
{ N*-tBz  
nFileLength = getFileSize(); {q0
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if(nFileLength == -1) u<BU4c/
p  
{ -&8( MT*  
System.err.println("File Length is not known!"); &R72$H9C8i  
} S:_Ms{S  
else if(nFileLength == -2) YO7U}6wBt  
{ EJkHPn  
System.err.println("File is not access!"); QO'Hyf t  
} :X;G]B .  
else Kq")\Ha,f  
{ X(N~tE  
for(int i=0;i<nStartPos.length;i++) EMmgX*i
u@  
{ p'/\eBhG]=  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); At(88(y-W  
} )5Khl"6!z  
for(int i=0;i<nEndPos.length-1;i++) Uk?G1]$mL  
{
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nEndPos = nStartPos[i+1]; <,]:jgX  
} b' o]Y  
nEndPos[nEndPos.length-1] = nFileLength; xo"GNFh!  
} cfLLFPhv)  
} XNYA\%:5S  
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.Mq#88o.*  
//启动子线程 &K9;GZS?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &uNec(c  
for(int i=0;i<nStartPos.length;i++) _ .vG)  
{ } !m43x/&  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o^"+X7)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  q#K{~:  
nStartPos,nEndPos,i); -N45ni87  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }Ce9R2  
fileSplitterFetch.start(); 7OV^>"S  
} YJJ1N/Z1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AjVC{\Ik  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m!V,W*RNr  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", k"N>pjgd$  
nEndPos = " + nFileLength); %~LY'cfPse  
// fileSplitterFetch[nPos.length-1].start(); zKQ<
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sfM"!{7  
//等待子线程结束 9p{4-]  
//int count = 0; #t+?eye~  
//是否结束while循环 > G\0Z[<v,  
boolean breakWhile = false; D#g-mqar:  

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:R;w<Tbz"  
while(!bStop) s6`E.Eevm  
{ P3zUaN\c  
write_nPos(); RM2Ik_IH[l  
Utility.sleep(500); ewMVUq*:  
breakWhile = true; F]$ Nu  
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for(int i=0;i<nStartPos.length;i++) (t4i&7-  
{ Oyl~j#h  
if(!fileSplitterFetch.bDownOver) B"^j>SF  
{ p_gN}v  
breakWhile = false; _{*}
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break; ZbFD|~[ V  
} 'oa.-g5  
} o=m5AUe?J  
if(breakWhile) 7)rQf{q7  
break; {?qfH>oFA  
m}]{Y'i]R  
&;BhL%)}  
//count++; QiPqN$n  
//if(count>4) _}l(i1o,/  
// siteStop(); |+cz\+  
} t~+M>Fjm?d  
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System.err.println("文件下载结束！"); -)V0D,r$[  
} BZeEZ2"  
catch(Exception e){e.printStackTrace ();} pzF_g-B  
} T\6Qr$t  
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//获得文件长度 1-kuK<KR  
public long getFileSize() V3,C5KKk&z  
{ 9jal D X  
int nFileLength = -1; `G\ qGllX  
try{ N*IroT3  
URL url = new URL(siteInfoBean.getSSiteURL()); ti5fsc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); aBAoSn  
httpConnection.setRequestProperty("User-Agent","NetFox"); %'2P4(  
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int responseCode=httpConnection.getResponseCode(); pH'Tx>  
if(responseCode>=400) ^twyy9VR  
{ ^ D0"m>3r  
processErrorCode(responseCode); 3D|Lb]=  
return -2; //-2 represent access is error H
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} RoqkT|#$  
a*M|_&MH*  
%['NPs%B  
String sHeader; WBjJ)vCA.  
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for(int i=1;;i++) F/v.
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{ !r/i<~'Bx  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %NLd"SV  
//Utility.log(in.readLine()); bb_elmb)n  
sHeader=httpConnection.getHeaderFieldKey(i); [v1$Lp  
if(sHeader!=null) z~H1f$}  
{ 5hE#y]pfN  
if(sHeader.equals("Content-Length")) ~kc#
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{ Y.m1d?H 1  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `_J&*Kk5  
break; Q& [!+s:2J  
} H I9/  
} Dl!0Hl  
else .][yH[F  
break; W{NWF[l8O?  
} 0akJv^^D  
} l+;S$evY  
catch(IOException e){e.printStackTrace ();} Au2^ T1F  
catch(Exception e){e.printStackTrace ();} +w0Wg.4V  
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Utility.log(nFileLength); `^#Rwn#  
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return nFileLength; ,2AulX1  
} ~<1s[Hu  
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//保存下载信息（文件指针位置） L=(-BYS  
private void write_nPos() MR
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{ l0&Fm:))k  
try{ {aE[h[=r  
output = new DataOutputStream(new FileOutputStream(tmpFile)); u6C_*i{2  
output.writeInt(nStartPos.length); fw%p_Cm  
for(int i=0;i<nStartPos.length;i++) RFw0u 0Nrz  
{ p5]W2i.,  
// output.writeLong(nPos); ;adZ*'6u  
output.writeLong(fileSplitterFetch.nStartPos); <EnmH/C.  
output.writeLong(fileSplitterFetch.nEndPos); LJrH_h8C  
} 0+mR y57  
output.close(); 9fp"r,aHN&  
} jdG'sITv  
catch(IOException e){e.printStackTrace ();} J{/hc} $  
catch(Exception e){e.printStackTrace ();} \Fjasz5E'  
} GW {tZaB  
CC^D4]ug  
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//读取保存的下载信息（文件指针位置） s(_z1  
private void read_nPos() ?g1eW q&  
{ 05F/&+V  
try{ Y*xgY*K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); iv`G}.Bo  
int nCount = input.readInt(); }w)}=WmD  
nStartPos = new long[nCount]; gLMb,buqC  
nEndPos = new long[nCount]; WX Fm'5Vr  
for(int i=0;i<nStartPos.length;i++) W~H`{x%Av>  
{ 1n8y4k)  
nStartPos = input.readLong(); Q`i@['?p  
nEndPos = input.readLong(); A^lm0[3q  
} 9>{ml&$  
input.close(); @+;.W>^h  
} #~Xj=M%
 
catch(IOException e){e.printStackTrace ();} ]Mq-67  
catch(Exception e){e.printStackTrace ();} ) `{jPK*`  
} 3MX#}_7A  
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cRI2$|  
private void processErrorCode(int nErrorCode) 4+8)0;<H  
{ o2|#_tGNUy  
System.err.println("Error Code : " + nErrorCode); nZiwR4kM  
} T6y~iNd<  
kRggVRM  
*L?~  
//停止文件下载 cvw1
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public void siteStop() &NF$_*\E  
{ z*HM_u  
bStop = true; )4fQ~)  
for(int i=0;i<nStartPos.length;i++) (tO4UI5!  
fileSplitterFetch.splitterStop(); 6[t(FcS  
7 @\i5  
p` ~=
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} *X3wf`C?  
} 7OLHYt9  
//负责部分文件的抓取 AclK9+V  
**FileSplitterFetch.java 5_A*IC]  
*/ N/>:})dav  
package NetFox; ~!ei]UP  
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import java.io.*; JCxQENsVqB  
import java.net.*; cZ%tJ(&\7X  
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public class FileSplitterFetch extends Thread { o5/BE`VD5c  
aF/DFaiYv  
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String sURL; //File URL @GXKqi  
long nStartPos; //File Snippet Start Position 4SUzR\  
long nEndPos; //File Snippet End Position T5`ML'Dej  
int nThreadID; //Thread's ID G9&2s%lu.e  
boolean bDownOver = false; //Downing is over I>rTqOK  
boolean bStop = false; //Stop identical ,g'>
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FileAccessI fileAccessI = null; //File Access interface xi"ff.  
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@?s>oSyV  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException }72\A
w5  
{ I[rR-4.F]  
this.sURL = sURL; r4cz?e|  
this.nStartPos = nStart; o]V.6Ge-  
this.nEndPos = nEnd; eSIG+{;&  
nThreadID = id; d@^%fVhG  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Xz:ha>}C  
} ;\|GU@K{hC  
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public void run() %J'/cmR&  
{ ;k0Jl0[}  
while(nStartPos < nEndPos && !bStop) .dYv.[?hL  
{ zT}vaU6  
h#Rza-?"\  
hrJ(][8  
try{ Yt=)=n  
URL url = new URL(sURL); 3ouy-SQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ";Cf@}i>  
httpConnection.setRequestProperty("User-Agent","NetFox"); !m))Yp-"H  
String sProperty = "bytes="+nStartPos+"-"; N,B!D~@  
httpConnection.setRequestProperty("RANGE",sProperty); b IxH0=f  
Utility.log(sProperty); {o^tSEN!-
 
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InputStream input = httpConnection.getInputStream(); tKyGD|g S  
//logResponseHead(httpConnection); IlO,Ql  
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byte[] b = new byte[1024]; 3S#p4{3  
int nRead; A|K=>7n]U  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) h$sOJs~6h  
{ GwXhn2  
nStartPos += fileAccessI.write(b,0,nRead); "]2^O  
//if(nThreadID == 1) JXRU9`3)A  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Y6Y"fb%K  
} C(h<s e?  
i@D4bd9lR  
#?\(l%  
Utility.log("Thread " + nThreadID + " is over!"); atd;)o0*0  
bDownOver = true; ,j{tGj_  
//nPos = fileAccessI.write (b,0,nRead); EF$ASN
h"  
} E;`^`T40  
catch(Exception e){e.printStackTrace ();} ]jI<Js*F  
} G2y1S/  
} rS!@AgPLE  
%H{;wVjK  
}oiNgs/N  
//打印回应的头信息 e*`ht+  
public void logResponseHead(HttpURLConnection con) GzaGTd.b  
{ 'aV'Am+:  
for(int i=1;;i++) -B/'ArOo]  
{ S W6oaa81  
String header=con.getHeaderFieldKey(i); K0oF=|  
if(header!=null) xR$T/]/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); czT2f  
Utility.log(header+" : "+con.getHeaderField(header)); o+8H:7,o'  
else 4P5^.\.  
break; vP#*if[V5  
} B R  
} 4 7mT  
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public void splitterStop() _UZPQ[  
{ N)D+FV29y  
bStop = true; ckV\f({  
} KkTE -$-  
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} Vg,nNa3  
mrsmul{  
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/* pl[@U<8aw  
**FileAccess.java F =*4]O  
*//文件访问(定位，写) }%PK %/ zI  
package NetFox; o_b3G  
import java.io.*; >l%8d'=Jl  
w-R.)  
u23_*W\  
public class FileAccessI implements Serializable{ x'\C'zeF  
nhMxw@Z\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 xDl; tFI  
RandomAccessFile oSavedFile; &uc`w{,Zs  
long nPos; rp"5176  
Id`V`|q  
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public FileAccessI() throws IOException Sx J0Y8#z  
{ 1,h:|  
this("",0); X=1o$:7  
} N2HD=[*cr  
__7}4mA  
cNwHY Z'  
public FileAccessI(String sName,long nPos) throws IOException ~@6l7H6{  
{ }[lP^Qs  
oSavedFile = new RandomAccessFile(sName,"rw"); XC;Icr)  
this.nPos = nPos; gjz-CY.hz  
oSavedFile.seek(nPos); _()1"5{  
} g-UCvY I  
/ yBrlf  
/W*Z.  
public synchronized int write(byte[] b,int nStart,int nLen) ]&P\|b1*g  
{ %GY'pQz  
int n = -1; })70S8k  
try{ [[^95:  
oSavedFile.write(b,nStart,nLen); w1-P6cf  
n = nLen; N>*+Wg$Ne  
} rOE: ap|KL  
catch(IOException e) *k8?$(  
{ 6@8t>"}  
e.printStackTrace (); 573,b7Yf  
} /RqWrpzx@  
}Md;=_TP  
-@_v@]:  
return n; *{+{h;p  
} #O;JV}y  
rq!
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} ILAn2W  
LFW`ISY{  
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/* q!'p   
**SiteInfoBean.java _h#I}uJ~  
*/ TvDC4tm-:  
package NetFox; `?N0?;  
m }HaJ  
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public class SiteInfoBean { =c*l!."0  
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F{a;=h#@Q  
private String sSiteURL; //Site's URL t>?tW
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private String sFilePath; //Saved File's Path *n EkbI/  
private String sFileName; //Saved File's Name

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private int nSplitter; //Count of Splited Downloading File , p~1fB-/  
 `ROHB@-  
6uo;4}0  
public SiteInfoBean() n}A!aC  
{//nSplitter的缺省值为5 Mhti  
//default value of nSplitter is 5 300w\9fn&  
this("","","",5); kUS]g r~i  
} `q<W %'Tb$  
U7D!w$4  
HLwMo&*rA  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) r#4/~a5i~  
{ lD3nz<p  
sSiteURL= sURL; 37jxl+  
sFilePath = sPath; :p: C  
sFileName = sName; 5a_8`csu  
this.nSplitter = nSpiltter; PgK7CG7G  
y-bUVw!Y  
?hkOL$v<9}  
} n8F5z|/  
@ G)yz!H  
;H~<.
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public String getSSiteURL() U3V5Jor#  
{ 1s.2z[B~  
return sSiteURL; |SjRss:i+  
} ;mk[!  
}H\I[5*  
1\&j)3mC  
public void setSSiteURL(String value) X@DW1<wEt  
{ rniM[7K  
sSiteURL = value; [DM0'4  
} ^ UmYW  
z.SC^/\o|  
bqAW  
public String getSFilePath() [#q>Aq$11  
{ ={ms@/e/T  
return sFilePath; {JP q.A  
} %?PFe}
 
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PY^#hC5:  
public void setSFilePath(String value) ^HJ?k:u  
{ WrGnLE kiV  
sFilePath = value; MqAi}z%  
} vW=L{8zu  
2Ckx.m&  
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public String getSFileName() &2`p#riAS  
{ (\{k-2t*^  
return sFileName; MWh Y&I+  
} a^p#M  
yk`qF'4]  
)e,O+w"  
public void setSFileName(String value) Y/FPkH4  
{ h0rPMd(K
 
sFileName = value; 8XB[CbO  
} ^'V :T Y  
VX$WL"A  
u##th8h4U  
public int getNSplitter() T^1 Z_|A  
{ aZWj52  
return nSplitter; Z]]Ur  
} W}CM;~*L  
:dSda,!z  
! ;t\lgMl  
public void setNSplitter(int nCount) 2]5{Xmmo9  
{ 8D*nU3O   
nSplitter = nCount; Ku75YFO,5  
} qcj {r
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} -d\sKc  
"r-P[EKpL  
:u14_^  
/* #s\@fp7A  
**Utility.java L"m^LyU  
*/ 3=YpZ\l}  
package NetFox; __g k:a>oQ  
-r={P_E6  
X/,)KTo7  
public class Utility { }4A] x`3  
qSc-V`*  
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public Utility() cKt=?  
{ CF '&Yo  
C!VhVOy>d  
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} $^ws#}j  
l_^SU8i57  
//线程睡眠 1[!v{F%]  
public static void sleep(int nSecond)
zw>L0gC  
{ )XN_|zCk  
try{ 4E39]vb  
Thread.sleep(nSecond); :RIz6Tz  
} QrYF Lh  
catch(Exception e) hIJtu;}zU  
{ }5;4'l8  
e.printStackTrace (); >rCD5#DG  
} {o}U"b<+Ra  
} )L:zr#  
k QuEG5n.-  
//日志 R~\R>\  
public static void log(String sMsg) =yf)Z^  
{ s@F&N9oh  
System.err.println(sMsg); r)*23&Ojs  
} fM
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lG7PM^Eb
 
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public static void log(int sMsg) {zwH3)|Hn  
{ ngo> ^9/8  
System.err.println(sMsg); n)e2?  
} LhJ
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} :ky`)F`  
wjA wJOw|  
>JyS@j}  
/* H7zN|NdNw  
**TestMethod.java jRJG .hcB5  
*/ qoO`)<  
package NetFox; 4&
}%GH>}  
u 272)@R  
8xPt1Sotq[  
public class TestMethod { hNN>Pd~;  
EeW ,-I  
-S'KxC  
public TestMethod() !5`MiH  
{ ///xx/weblogic60b2_win.exe .-d'*$ yJ  
try{ 3UZd_?JI[^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); V8^la'_j  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~:ASv>m  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~g{j)"1  
fileFetch.start(); *~vB6V|1  
} Er;/zxg9p  
catch(Exception e){e.printStackTrace ();} l0qaTpn  
1Bj.MQ^  
|P >"a`  
} 'f5 8Jwql  
!eW1d0n'+f  
UA>=# $  
public static void main(String[] args) u]yy%@U1  
{ "q=Cye  
new TestMethod(); (dy(.4W\  
} Q{[@n  
} wQhNQ(H~\  
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