http断点续传简单实现（java)

/* R$;n)_H  
**SiteFileFetch.java ^u3V E  
*/ Y5fLmPza  
package NetFox; U qG .:@T  
import java.io.*; LYlDc;<A  
import java.net.*; Ol4+_n8xj  
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public class SiteFileFetch extends Thread { X,9 M"E 2  
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SiteInfoBean siteInfoBean = null; //文件信息Bean <uj8lctmP  
long[] nStartPos; //开始位置 Mq';S^  
long[] nEndPos; //结束位置 [+qCs7'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 d)~Fmi;  
long nFileLength; //文件长度 f/CuE%7BR  
boolean bFirst = true; //是否第一次取文件 3fN.bU9_  
boolean bStop = false; //停止标志 B"%{i-v>**  
File tmpFile; //文件下载的临时信息 re> rr4@  
DataOutputStream output; //输出到文件的输出流 Jx'i2&hGN  
/x3/Ubmz~x  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） q^6+!&"  
public SiteFileFetch(SiteInfoBean bean) throws IOException eh"3NRrN  
{ ZvcJK4hi  
siteInfoBean = bean;
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); qCv20#!"|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .*e
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if(tmpFile.exists ()) >>[G1  
{ =]k {"?j  
bFirst = false; z({hiVs  
read_nPos(); #-h\.#s  
} znJ'iVf  
else (
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{   zxp`  
nStartPos = new long[bean.getNSplitter()]; L/"0ws_  
nEndPos = new long[bean.getNSplitter()]; q%ow/!\;  
} 7'OtruJ  
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} hR.@b*q?R  
: }`-B0  
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public void run() 8uA,iYD  
{ w9|w2UK  
//获得文件长度  x]z2Z*  
//分割文件
j) ,,"54*  
//实例FileSplitterFetch ^ "\R\COQ  
//启动FileSplitterFetch线程 &N;-J2M  
//等待子线程返回 <x!GE>sf+  
try{ /EG~sR
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if(bFirst) @u1zB:  
{ 5aa<qtUjH  
nFileLength = getFileSize(); B
<-
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if(nFileLength == -1) E#s)52z=B  
{ 'TAUE{{  
System.err.println("File Length is not known!"); u a\,->  
} 8iekEG$H  
else if(nFileLength == -2) pAk/Qxl3eo  
{ wfjnA~1h  
System.err.println("File is not access!"); R<V!%rL;;  
} san,|yrMn  
else T,$WlK Wj  
{ 57 #6yXQ  
for(int i=0;i<nStartPos.length;i++) <r3J0)r
}  
{ *s;|T?~i  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
5[Pr|AY  
} pa{re,O"e  
for(int i=0;i<nEndPos.length-1;i++) *& m#qEv  
{ 5 QO34t2  
nEndPos = nStartPos[i+1]; Yf[Qtmh]I  
} Vi$-Bw$@  
nEndPos[nEndPos.length-1] = nFileLength; K).n.:vYZ  
} ;m2<eS`o'  
} 72,rFYvpK  
@}:uu$OH  
X_v[MW  
//启动子线程 Sua[O$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _FwK-?4E-  
for(int i=0;i<nStartPos.length;i++) C2{lf^9:&  
{ ?@n/v F  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y{*u&^0{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J sEa23  
nStartPos,nEndPos,i); X*L;.@xA  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); HfLLlH<L`&  
fileSplitterFetch.start(); J6jwBo2m  
} W}|'#nR  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4BwQA#zE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); t5lO'Ll*Q]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", CwX Z  
nEndPos = " + nFileLength); JBnKK  
// fileSplitterFetch[nPos.length-1].start(); lb:/EUd5  
F"N60>>  
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//等待子线程结束 i{I~mrm/'\  
//int count = 0; &* E+N[  
//是否结束while循环 sFBneBub  
boolean breakWhile = false; jM:Y'l]  
|!F5.%PY  
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while(!bStop) BW,mwq  
{ ( 9]_ HW[  
write_nPos(); D13Rx 6b  
Utility.sleep(500); al`3Lu0  
breakWhile = true; "l >Igm  
a5G/[[cwTV  
q{ /3V  
for(int i=0;i<nStartPos.length;i++) C4}*)a  
{ s{w[b\rA  
if(!fileSplitterFetch.bDownOver) X=C1/4wU  
{ FEo269Ur  
breakWhile = false; Qeu\&%C!<  
break; >><.3  
} 7r{83_B  
} a {ab*tM  
if(breakWhile) fo4.JyBk  
break; n$[f94d=  
6; Y0a4Ax  
& /4k7X}y  
//count++; V)P&Zw  
//if(count>4) <94_@3  
// siteStop(); %_
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} $3,ryXp7  
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System.err.println("文件下载结束！"); MC&\bf  
} + S4fGT  
catch(Exception e){e.printStackTrace ();} CU7F5@+  
} 6{qIU}!  
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//获得文件长度 =H<0o?8?c  
public long getFileSize() S60IPya  
{ 8J)xzp`*)  
int nFileLength = -1; m4:^}O-#  
try{ A^2L~g[^Q  
URL url = new URL(siteInfoBean.getSSiteURL()); +\"-P72vjk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -VZRujl  
httpConnection.setRequestProperty("User-Agent","NetFox"); Db"DG(  
8_K60eXz  
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int responseCode=httpConnection.getResponseCode(); !Oi~:Pp  
if(responseCode>=400) na^sBq?\  
{ 3gQPKBpc  
processErrorCode(responseCode); I\|N  
return -2; //-2 represent access is error 1
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} ,_ag;pt
9)  
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String sHeader; g+PPW88P;  
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for(int i=1;;i++)  ,Yhw
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{ (5^ZlOk3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -6sW6;Q  
//Utility.log(in.readLine()); ]S 7^ITn  
sHeader=httpConnection.getHeaderFieldKey(i); h8jD}9^  
if(sHeader!=null) *V(Fn-6(  
{ (Vg}Hh?p  
if(sHeader.equals("Content-Length")) V^Rkt%JY  
{ $j)hNWI  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); fE,9zUo  
break; 0@Kkl$O>mb  
} 7-_vY[)/  
} UK*qKj.)  
else Tp<k<uKD  
break; Ri>?KrQF%  
} H(Ms^8Vs~:  
} @6o]chJo  
catch(IOException e){e.printStackTrace ();} z&4~x!-_  
catch(Exception e){e.printStackTrace ();} 6k?`:QK/sl  
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Utility.log(nFileLength); H;WY!X$x  
}jF+`!*
!  
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return nFileLength; v[<Bjs\q5  
} 1@XgTL4  
)y7_qxwbV  
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//保存下载信息（文件指针位置） `#IcxweA  
private void write_nPos() ELa ja87  
{ |Y_ -  
try{ }fhHXGK.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0_eQlatb  
output.writeInt(nStartPos.length); UEzi*"-v2  
for(int i=0;i<nStartPos.length;i++) ZI ?W5ISdg  
{ K^%-NyV  
// output.writeLong(nPos); n"aCt%v  
output.writeLong(fileSplitterFetch.nStartPos); "r.2]R3  
output.writeLong(fileSplitterFetch.nEndPos); Hlj6$%.  
} 1K|@h&@  
output.close(); (*l2('e#@  
} \Mi#{0f+q  
catch(IOException e){e.printStackTrace ();} INMP"1  
catch(Exception e){e.printStackTrace ();} ecH/Wz1  
} g8pm2o@S  
|;;!8VO3J  
M:ai<TZ]  
//读取保存的下载信息（文件指针位置） Qs+k)e,  
private void read_nPos() F'J [y"~_  
{ BH:  
try{ _py2kjA6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \k&1*b?h  
int nCount = input.readInt(); )wf\F6jN  
nStartPos = new long[nCount]; V"d=.Hb>  
nEndPos = new long[nCount]; iH)Nk^  
for(int i=0;i<nStartPos.length;i++) DacJ,in_I{  
{ Nh)[rx  
nStartPos = input.readLong(); T'rjh"C&|  
nEndPos = input.readLong(); `n-vjjG%#  
} Z^tGu7x  
input.close(); Qd8b-hg  
} 9d[qhkPu)  
catch(IOException e){e.printStackTrace ();} O<,r
>b,  
catch(Exception e){e.printStackTrace ();} MguL$W&l  
} kN'Thq/ZE  
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private void processErrorCode(int nErrorCode) N <pbO#e  
{ -ID!pTvW  
System.err.println("Error Code : " + nErrorCode); PvOC5b  
} Lk(S2$)*  
-l.pA(O  
tjb/[RQ  
//停止文件下载 cgNt_8qC  
public void siteStop() lYQtv=q  
{ /e5\9  
bStop = true; -^fzsBL.  
for(int i=0;i<nStartPos.length;i++) |[w^eg  
fileSplitterFetch.splitterStop(); @P70W<<  
;6<zjV7}  
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} 0(TvQ{  
} /VtlG+dLl  
//负责部分文件的抓取 rdI]\UH  
**FileSplitterFetch.java ?Le
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*/ LkaG[^tfN  
package NetFox; b{HhS6<K?  
?Y!^I2Y6  
|4xo4%BQ>  
import java.io.*; {W'8T}q  
import java.net.*; 4I.1D2 1jA  
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public class FileSplitterFetch extends Thread { <[8@5?&&  
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String sURL; //File URL Mryn>b`cB  
long nStartPos; //File Snippet Start Position #L1>dHhat  
long nEndPos; //File Snippet End Position HwW6tQ  
int nThreadID; //Thread's ID GXEcpc08  
boolean bDownOver = false; //Downing is over f#mx:Q.7I  
boolean bStop = false; //Stop identical }MjQP R  
FileAccessI fileAccessI = null; //File Access interface gD5P!}s[u0  
*zSxG[s  
=WjJN Q  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4a 4N C  
{ 7%tR&F -u  
this.sURL = sURL; \A
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this.nStartPos = nStart; .S6ji~;r  
this.nEndPos = nEnd;
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nThreadID = id; () <`t}FQ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w#
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} #'c%  
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public void run() !(yT7#?hP  
{ - &NQ\W  
while(nStartPos < nEndPos && !bStop) qTS@D  
{ 4D GY6PS  
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try{ QK'`=MU  
URL url = new URL(sURL); uX98iJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h$|3dz N  
httpConnection.setRequestProperty("User-Agent","NetFox"); E0
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String sProperty = "bytes="+nStartPos+"-"; 8T<@ @6`T  
httpConnection.setRequestProperty("RANGE",sProperty); Y[h#hZ  
Utility.log(sProperty); yT&x`3f"i  
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InputStream input = httpConnection.getInputStream(); A1=_nt)5  
//logResponseHead(httpConnection); AzxL%,_  
RP(a,D|  
@~s~/[  
byte[] b = new byte[1024]; / =-6:L  
int nRead; ia_Z\q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) k)|'JDm  
{ /%5_~Jkr,  
nStartPos += fileAccessI.write(b,0,nRead); pFEZDf}:  
//if(nThreadID == 1) })KJ60B  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2+,5p  
} }
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Z@}sCZ=#A  
Utility.log("Thread " + nThreadID + " is over!"); gm(De9u  
bDownOver = true; %3rTQ:X
 
//nPos = fileAccessI.write (b,0,nRead); :fRmUAK%  
} Z(KmS(  
catch(Exception e){e.printStackTrace ();} :4%<Rp  
} TeKC} NW  
} m"<4\;GK  
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]7v81G5E  
//打印回应的头信息 |O57N'/  
public void logResponseHead(HttpURLConnection con) sfyBw  
{ UOw~rK   
for(int i=1;;i++) zIP[R):3&U  
{ <njIXa{  
String header=con.getHeaderFieldKey(i); &S<?07Z  
if(header!=null) C/CN '  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  dhZZb  
Utility.log(header+" : "+con.getHeaderField(header)); D*CIE\+  
else =E&24  
break; T_uNF8Bh  
} f( ]R/'o  
} ok%EqO  
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"fRlEO[9  
public void splitterStop() |^Y*~d<H  
{ 1a5?)D  
bStop = true; y>@v>S  
} CKx\V+\O  
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v$[ @]`  
} \nC5 ,
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|VTWw<{LX  
BO8%:/37[4  
/* 2^cAK t6bC  
**FileAccess.java w/qQ(]n8  
*//文件访问(定位，写) -zPm{a  
package NetFox; d|>9rX+f  
import java.io.*; Tq9,c#}&  
Nn
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2
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public class FileAccessI implements Serializable{ imo'(j7  
!}iLO0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 )EhTM-1  
RandomAccessFile oSavedFile; &W&7bZ$;  
long nPos; U,oD44  
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(nkUeQQN  
public FileAccessI() throws IOException z2rQ$O-#  
{ Rg%R/p)C  
this("",0); $ 1akI  
} zi?qK?m  
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public FileAccessI(String sName,long nPos) throws IOException 0|WOReskK  
{ h-z%C6  
oSavedFile = new RandomAccessFile(sName,"rw"); 1.hOE>A%  
this.nPos = nPos; .a 'ETNY:>  
oSavedFile.seek(nPos); ?9o#%?6k  
} ~0VwF  
>xxXPvM<`  
H j>L>6>  
public synchronized int write(byte[] b,int nStart,int nLen) X;K8,A7`  
{ sq8tv]  
int n = -1; OhA^UP01-  
try{ d+gk q\  
oSavedFile.write(b,nStart,nLen); !m
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n = nLen; }0k"SwX  
} 9b{g+lMZo  
catch(IOException e) UQC'(>.}  
{ w3>Y7vxiz`  
e.printStackTrace (); &*V0(  
} PO=ZxG
  
#C;#$|d  
sg!=Q+  
return n; Vp- n(Z  
} |Fh`.iT%c  
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} @&am!+z  
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/* 2i4Dal  
**SiteInfoBean.java  d'**wh,  
*/ ?kT~)k  
package NetFox; ,M+h9_&0?  
"6[Ax{c
M  
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public class SiteInfoBean { `Tm8TZd66  
?j^?@%f0  
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private String sSiteURL; //Site's URL ]aL [  
private String sFilePath; //Saved File's Path D@YM}HXuj  
private String sFileName; //Saved File's Name S+e-b'++?  
private int nSplitter; //Count of Splited Downloading File 1W6n[
Xg  
U4mh!  
' /@!"IXz  
public SiteInfoBean() ['9OGV\  
{//nSplitter的缺省值为5 ]i_):@  
//default value of nSplitter is 5 Qbe{/  
this("","","",5); +kdU%Sm  
} tM?I()Y&P  
lw/
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`P)64So-1  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9N3oVH
c?  
{ &55uT;7] a  
sSiteURL= sURL; |[n|=ORI'  
sFilePath = sPath; \gPNHL*  
sFileName = sName; -7A!2mRiz  
this.nSplitter = nSpiltter; fxf GJNR  
p%M(G#gOgP  
c9_4
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} h.+,
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qz_TcU'  
"~,(
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public String getSSiteURL() B )3SiU  
{ daokiU+l2  
return sSiteURL; a1Y_0  
} 14)kKWG  
m`4j|5  
SUQ}^gn]  
public void setSSiteURL(String value) EXM/>PG  
{ I$P7%}  
sSiteURL = value; g5TLX&Bd  
} ysP/@;jC  
3By>t!~Q  
:WKyEt!3  
public String getSFilePath() OKNs (H  
{ jzOMjz~:)  
return sFilePath; 0O9 Lg}  
} +Y%I0.?&5  
Sv]"Y/N  
(fjXp75  
public void setSFilePath(String value) j?` D\LZhf  
{ ]KII?{<k  
sFilePath = value; UqQZ A0e  
} K {N;k-  
,Y/>*,J  
a*ixs'MJ  
public String getSFileName() }jy7,+  
{ hFF&(t2{^  
return sFileName; dodz|5o%  
} kJ:5msKwC  
jI pcMN<  
er}'}n`@q  
public void setSFileName(String value) ^|axtVhMO  
{ _rWXcK3cjr  
sFileName = value; SodW5v a  
} GTX&:5H\t  
cyn]>1ZM  
f#JF5>o  
public int getNSplitter() ZXRN?
b  
{ uqH! eN5  
return nSplitter; ntUVh
IE0  
} RB 0j!H:  
_!T$|,a  
ku8Z;ONeH  
public void setNSplitter(int nCount) yOm6HA``hT  
{ P>cJ~FM  
nSplitter = nCount; Z\yLzy#8  
} +c2>j8e6  
} *^m.V=  
h!3Z%M  
7 @Qlp$[F  
/* E&=?\KM  
**Utility.java gM:oP.  
*/ T{kwy3  
package NetFox; `9)2nkJk'z  
  r3K:  
x=<
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public class Utility { F>nrV  
@)Y7GM+^  
]nGA1S{  
public Utility() YtKX\q^.  
{ y(g Otg  
B_1u<00kg  
MO+0]uh:  
} M0\[hps~X  

$G.|5sEk  
//线程睡眠 f)fw87UPc  
public static void sleep(int nSecond) ~d8o,.n`1  
{ 1e%Xyqb  
try{ e/%YruzS  
Thread.sleep(nSecond); >sY+Y22U  
} EnAw8Gm*  
catch(Exception e) U5s]dUs (  
{ f4^_FK&  
e.printStackTrace (); 5,fzB~$TX(  
} k!rz8S"  
} cMKh+r  
NV~i4R*#  
//日志 LLN^^>5|l  
public static void log(String sMsg) !y0 O['7  
{ #J9XcD{1  
System.err.println(sMsg); nr6U> KR^  
} =l{KYv  
&WS%sE{p_  
D]y.!D{l2  
public static void log(int sMsg) A>S2BL#=  
{ l;i u`  
System.err.println(sMsg); cE?
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} n\,W:G9AR7  
} epe}^Pl  
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/* /zAx`H  
**TestMethod.java [Y+
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*/ 4(]('[M  
package NetFox; 3iwZUqyq  
n`1i k'x?  
M1\/ueOe  
public class TestMethod { OW^7aw(N6  
<#Dc(VhT  
$'wl{D"  
public TestMethod() S6I8zk)Z4  
{ ///xx/weblogic60b2_win.exe n_Dhq(.  
try{ qlP=Y .H  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); D:0PppE  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);  su$juI{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); pj`-T"Q  
fileFetch.start(); .`9KB3  
} S{06bLXU"  
catch(Exception e){e.printStackTrace ();} BGS6uV4^>  
ce\-oT  
#(G&%I A|;  
} Zl*!pQ  
7y3; F7V  
sa($3`d  
public static void main(String[] args) A |B](MW%O  
{ /zM7G
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new TestMethod(); ,\i q'}i  
} WfVie6  
} ]Ea6Z  
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