http断点续传简单实现（java)

/* n0U^gsD4J  
**SiteFileFetch.java FFbMG:>:  
*/ 8_>\A= E  
package NetFox; :84ja>`c  
import java.io.*; hiaj!&+Q  
import java.net.*; G#5Cyu<r!  
@iUzRsl  
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public class SiteFileFetch extends Thread { vQ+}rHf`[  
qh0)~JL4  
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SiteInfoBean siteInfoBean = null; //文件信息Bean dpZ7eJ  
long[] nStartPos; //开始位置 ) EEr?"  
long[] nEndPos; //结束位置 7t5X  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7oF`Os+U  
long nFileLength; //文件长度 k(=\&T  
boolean bFirst = true; //是否第一次取文件 <Xp F  
boolean bStop = false; //停止标志 #1hT#YN  
File tmpFile; //文件下载的临时信息 ,9|%  
DataOutputStream output; //输出到文件的输出流 qt/syF&s  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 'e3y|  
public SiteFileFetch(SiteInfoBean bean) throws IOException x~s>  
{ H; TmG<S  
siteInfoBean = bean; 90sMS]a  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); V==' 7n  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); FtM7+>Do
.  
if(tmpFile.exists ()) VT3Zo%Xx  
{ Sx;zvc  
bFirst = false; &-<"HW  
read_nPos(); wuzz Wq  
} $@x3<}X;  
else
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{ 2@08V|  
nStartPos = new long[bean.getNSplitter()]; `"AjbCL  
nEndPos = new long[bean.getNSplitter()]; }S*6+4  
} z$7YC49^  
+Jt"JJ>%k  
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} Q)#<T]~=  
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public void run() UgJlXB|a%2  
{ ~(aq3ngo.  
//获得文件长度 8S]Mf*~S'  
//分割文件 &M>S$+I n  
//实例FileSplitterFetch L!S-f4^5  
//启动FileSplitterFetch线程 yel>-=Vn  
//等待子线程返回 d/Py,  
try{ ,EZ&n[%Ko  
if(bFirst) bcM#KA  
{ *Z{$0K  
nFileLength = getFileSize(); e"r}I!.  
if(nFileLength == -1) /lr RbZ  
{ KG>.7xVWV7  
System.err.println("File Length is not known!"); + W@r p#  
} Z6D4VZVF  
else if(nFileLength == -2) <g*rTqT'  
{ M|n)LyL  
System.err.println("File is not access!"); %M}zi'qQ?  
} 7IK<9i4O  
else dZ%b|CUb  
{ q{U -kuui  
for(int i=0;i<nStartPos.length;i++) Maa5a
  
{ ~;+i[Z&e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .Z_U]_(  
} &51/Pm2O  
for(int i=0;i<nEndPos.length-1;i++) l06 q1M 3  
{ "b1_vA]03  
nEndPos = nStartPos[i+1]; I.KYWs  
} v/m`rc
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nEndPos[nEndPos.length-1] = nFileLength; v~jN,f*  
} So`xd *C!  
} l$zNsf.  
e3S6+H),I  
//J:p,AF  
//启动子线程 ]G1j\wnF  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; t<`ar@}  
for(int i=0;i<nStartPos.length;i++) HhqqJEp0  
{ DVB:8"Bu  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (S2<6Nm8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $hKgTf?  
nStartPos,nEndPos,i); \&TTe8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E32z(:7M  
fileSplitterFetch.start(); `/HygC6  
} OW-+23)sj  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F)gL=6h  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Qb(
CH  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Rw/G =zV@2  
nEndPos = " + nFileLength); ED?s[K  
// fileSplitterFetch[nPos.length-1].start(); E_H1X'|qS4  
qL'3MY.!  
Q'8v!/"}p{  
//等待子线程结束 ?-i|f_`  
//int count = 0; kkJg/:g  
//是否结束while循环 jV<LmVcZY  
boolean breakWhile = false; r p@=
  
i44:VR|  
\6lXsu;I.X  
while(!bStop) piId5Gx7  
{ 7Ru0
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write_nPos(); AGv;8'`  
Utility.sleep(500); .s!:p pwl  
breakWhile = true; v,M2|x\r}  
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for(int i=0;i<nStartPos.length;i++) ,88Y1|:X  
{ -"cN9RF  
if(!fileSplitterFetch.bDownOver) xS(sRx+A  
{ TWs|lhC7!  
breakWhile = false; >N,G@{FR  
break; CD[7h  
} #ERn 8k  
} VLO>{"{'  
if(breakWhile) :?p{ga9  
break; p0tv@8C>  
v4v+;[a%  
)`Fr*H3{  
//count++; mi-\PD>X  
//if(count>4) JNu- z:J  
// siteStop(); #E ~FF@a  
} =.o-R=:d  
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w1}[lq@  
System.err.println("文件下载结束！"); )F~_KD)7jJ  
} a>kDG <.A  
catch(Exception e){e.printStackTrace ();} i]YQq!B  
} NRl"!FSD;"  
zJsoenU  
r zvX~B6  
//获得文件长度 2Z97Tq  
public long getFileSize() ,S5#Kka~a  
{ s{IoL_P
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int nFileLength = -1; aQG#bh [  
try{ srS
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URL url = new URL(siteInfoBean.getSSiteURL()); T9$U./69-L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <VBw1|)$@  
httpConnection.setRequestProperty("User-Agent","NetFox"); :1{j&$  
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int responseCode=httpConnection.getResponseCode(); 4ku/3/6  
if(responseCode>=400) {Q-U=me\  
{ %*gO<U4L]  
processErrorCode(responseCode); PWmz7*/  
return -2; //-2 represent access is error 68!]q(!6F  
} y{"E)YY  
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I,S'zH
R  
String sHeader; dL
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K
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for(int i=1;;i++) J)G3Kq5>:b  
{ y8 Nb8m  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); HUghl2L.<  
//Utility.log(in.readLine()); l<HRD  
sHeader=httpConnection.getHeaderFieldKey(i); %b?Pasf.  
if(sHeader!=null) &-*nr/xT  
{ k|_2aQ02  
if(sHeader.equals("Content-Length")) "4`%NA  
{ <oO,CXF  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); f@{C3E dd  
break; IF:M_   
} saT9%?4-  
} %C)JmaQ{9  
else VZ,T`8"  
break; r#Mx~Zg~  
} W<4\4  
} J v#^GNm  
catch(IOException e){e.printStackTrace ();} Lm?*p>\Q  
catch(Exception e){e.printStackTrace ();} n1t(ns
|  
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Utility.log(nFileLength); j[fQs,efK  
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return nFileLength; Q#N+5<]J)#  
} X\x9CA  
/kz&9FM  
d.AjH9 jg  
//保存下载信息（文件指针位置） [z~Nw#  
private void write_nPos() K[[k,W]qb  
{ OeYLL4H  
try{ @NIypi$T  
output = new DataOutputStream(new FileOutputStream(tmpFile)); T]W -g  
output.writeInt(nStartPos.length); uI2'jEjO  
for(int i=0;i<nStartPos.length;i++) @>]3xHE6#=  
{ @"!SU'*  
// output.writeLong(nPos); q(7D8xG;F  
output.writeLong(fileSplitterFetch.nStartPos); 5avO48;Vc  
output.writeLong(fileSplitterFetch.nEndPos); u\xm8}A  
} @9h#o5y q  
output.close(); ~Z2eQx jtM  
} l:eNu}{&  
catch(IOException e){e.printStackTrace ();} C6w{"[Wv=X  
catch(Exception e){e.printStackTrace ();} @"8QG^q8de  
} !cb#fl  

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//读取保存的下载信息（文件指针位置） BcLt95;.\  
private void read_nPos() Y+GeT#VHe  
{ 'EV *-_k  
try{ 1%"` =$q%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^rwSbM$  
int nCount = input.readInt(); lc-|Q#$3$  
nStartPos = new long[nCount]; Bs?
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nEndPos = new long[nCount]; |esjhf}H>v  
for(int i=0;i<nStartPos.length;i++) V+24-QWh  
{ =LxmzQO#  
nStartPos = input.readLong(); }NCvaO  
nEndPos = input.readLong(); a1SOC=.M
;  
} 1RbYPX  
input.close(); $0}bi:7  
} cEdJn
@ ,  
catch(IOException e){e.printStackTrace ();} 3.X0!M;x  
catch(Exception e){e.printStackTrace ();} j\f$r,4  
} *]WXM.R8  
 ~C/KA6H  
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private void processErrorCode(int nErrorCode) 1`lFF_stkP  
{ UwkX[u  
System.err.println("Error Code : " + nErrorCode); 1fv~r@6s  
} ~C'nBV  
(Fzh1#  
#<Nvy9  
//停止文件下载 NCnId}
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public void siteStop() hxVM]e[  
{ bU]N^og^  
bStop = true; ==1/N{{R  
for(int i=0;i<nStartPos.length;i++) i8_x1=A  
fileSplitterFetch.splitterStop(); U!:!]DX(  
2?iOB
6  
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} WgJAr73 l  
} q_y,j&  
//负责部分文件的抓取 ;&6PL]/
d  
**FileSplitterFetch.java ;-pvc<_c<  
*/ wp.e3l  
package NetFox; qYZ7Zt;  
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F9P0cGDs  
import java.io.*; 4>VZk^%b#  
import java.net.*; 9jGuelwN  
n/oipiYx  
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public class FileSplitterFetch extends Thread { BddECY,z  
NcBe|qxQ  
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String sURL; //File URL MW$H/:3  
long nStartPos; //File Snippet Start Position C2rj
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long nEndPos; //File Snippet End Position 7. 9s.*  
int nThreadID; //Thread's ID ynZ[c8.  
boolean bDownOver = false; //Downing is over ;K\N  
boolean bStop = false; //Stop identical eH%L?"J~:  
FileAccessI fileAccessI = null; //File Access interface 2~WFLD  
_$\5ZVe  
VnSj:LUD  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4Sstg57x~  
{ 8o7]XZE=)  
this.sURL = sURL; (1AA;)`Kp  
this.nStartPos = nStart; Di<J6xu  
this.nEndPos = nEnd; `JWYPs
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nThreadID = id; >Ug?O~-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w<~<(5mM5;  
} }SMJD  
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public void run() O%K?l}e  
{ @=NVOJy}c  
while(nStartPos < nEndPos && !bStop) =HV-8C]  
{ `)=A!x y  
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try{ NnLhJPh  
URL url = new URL(sURL); 2Cd --W+=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6"Lsui??  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~26s7S}  
String sProperty = "bytes="+nStartPos+"-"; FK@ f'  
httpConnection.setRequestProperty("RANGE",sProperty); AIl$qPKj&  
Utility.log(sProperty); oIvnF:c  
vbA7I<;  
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InputStream input = httpConnection.getInputStream(); ))IgB).3M  
//logResponseHead(httpConnection); 7t-*L}~WA  
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<a+eF}*2  
byte[] b = new byte[1024]; X}j'L&{F@  
int nRead; 0?F@iB~1F  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) AZy~Q9Kc  
{ -':"6\W  
nStartPos += fileAccessI.write(b,0,nRead); noaN@K[GO  
//if(nThreadID == 1) RZd4(7H=q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7"n1it[RJ8  
} Lk`k>Nn)  
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Utility.log("Thread " + nThreadID + " is over!"); ? gA=39[j  
bDownOver = true; *]m kyAhi  
//nPos = fileAccessI.write (b,0,nRead); ci,o8 [Y  
} (Gi+7GMV'  
catch(Exception e){e.printStackTrace ();} g\qL}:  
} n=G>y7b  
} )7I.N]=  
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UN*dU  
//打印回应的头信息 r,3Ww2X-  
public void logResponseHead(HttpURLConnection con) Fp5NRM*-!  
{ hmBnV  
for(int i=1;;i++) \za5:?[xB  
{ ?Rt1CDu  
String header=con.getHeaderFieldKey(i); x0u?*5-t  
if(header!=null) 4>$ ;gH  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^p"4)6p-W  
Utility.log(header+" : "+con.getHeaderField(header)); -B*<Q[_  
else hsHVX[<5`  
break; D%jD8p  
} hi {2h04  
} _H4$$  
\3Q:K|  
+EST58  
public void splitterStop() ^_*jp[!`b$  
{ Sv~YFS :oy  
bStop = true; @ate49W  
} <+? Y   
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} z*M}=`M$  
:]B% >*;}  
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/* Y!Uu173  
**FileAccess.java PPwxk;  
*//文件访问(定位，写) + ZR(  
package NetFox; ^MW\t4pZ  
import java.io.*; ,bZ"8Z"lss  
+CnyK(V  
<qbZG}u  
public class FileAccessI implements Serializable{ M^j<J0(O  
*? K4!q'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /S7+B]  
RandomAccessFile oSavedFile; ]z-']R;  
long nPos; %~#!NX  
=bs.2aN&^  
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public FileAccessI() throws IOException F5N>Uqr*oN  
{ [{S;%Jj*X/  
this("",0); .k# N7[q=  
} S|K|rDr0n  
~In{lQ[QX  
; g Z%U  
public FileAccessI(String sName,long nPos) throws IOException M&uzOK+  
{ v}7@CP]nV  
oSavedFile = new RandomAccessFile(sName,"rw"); P]pmt1a  
this.nPos = nPos; O"
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oSavedFile.seek(nPos); tWpl`HH  
} KI Ek/]<H  
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public synchronized int write(byte[] b,int nStart,int nLen) `fQM  
{ `t{D7I7  
int n = -1; {E!$ xY8  
try{ )8pcf`h{  
oSavedFile.write(b,nStart,nLen); uk`T+@K  
n = nLen; zc6Ho  
} !"g=&Uy&  
catch(IOException e) VDB$"T9#  
{ i Td-n9  
e.printStackTrace (); L7SEswMti  
} jg~_'4f#  
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q<-%L1kc1  
return n; d32@M~vD  
} >$2E1HW.  
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} h6g=$8E  
|n+#1_t%  
|.1qy,|!X  
/* 98BYtxa
 
**SiteInfoBean.java $GQphXb$  
*/
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package NetFox; E;9Z\?P  
8ou e-:/a  
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public class SiteInfoBean { riID,aut  
hZ!oRWIU%G  
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private String sSiteURL; //Site's URL y&7YJx  
private String sFilePath; //Saved File's Path .j:i&j(  
private String sFileName; //Saved File's Name joe9.{  
private int nSplitter; //Count of Splited Downloading File 2*+3RrJ  
JYPxd~T/-  
2bWUa~%B  
public SiteInfoBean() -r!42`S  
{//nSplitter的缺省值为5 7nm}fT z7  
//default value of nSplitter is 5 &kb\,mQ  
this("","","",5); Q`N18I3  
} $9G3LgcS  
O'fk&&l  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .\$Wy$ d  
{ d&hD[v  
sSiteURL= sURL; ;vMn/  
sFilePath = sPath; . =&Jo9  
sFileName = sName; ]22C)<  
this.nSplitter = nSpiltter; (/'h4KS@  
 KZ]r8  
.%_)*NUZ  
} 4&|C}  
)B81i! q  
d5Qd'  
public String getSSiteURL() `"B^{o  
{ Y=9j2 ]t  
return sSiteURL; q&Q/?g>f  
} ^b=XV&{q  
sD2 ^_w6j  
(s088O  
public void setSSiteURL(String value) [G\o+D?2  
{ l1}R2lSEO  
sSiteURL = value; jA,|JgN|n  
} )i @1XH"D  
&RWM<6JP  
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public String getSFilePath() @.k5MOn  
{ ^+M><jE9  
return sFilePath; }
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} 82|q7*M*.  
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public void setSFilePath(String value) i-,'.w  
{ C,.-Q"juH  
sFilePath = value; @m?{80;uQ  
} >{QdMn  
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@LcT-3u  
public String getSFileName() qp\BV#E  
{ [yC"el6PM  
return sFileName; /tP7uVL R  
} Ae6("Oid  
?ZaD=nh$mK  
v`SY6;<2  
public void setSFileName(String value) C%]."R cMC  
{ E`t
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sFileName = value; p'80d:  
} 9 Va40X1  
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public int getNSplitter() { UOhVJy  
{ l~['[Ub0)
 
return nSplitter; YN^T$,*  
} {
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D M}s0O$0  
public void setNSplitter(int nCount) "7d.i(vw  
{ a1|c2kT  
nSplitter = nCount; .uKx>YB}  
} EI\v  
}  g#qNHR  
P_}/#N{C  
q`[K3p   
/* {y b D  
**Utility.java sQtf,e|p  
*/ 5DOE3T`^Oc  
package NetFox; oIR.|=Hk{  
y AOg\+  
"5}%"-#  
public class Utility { +2Ql~w@$^l  
waCboK'  
5%P[^}  
public Utility() E=kw)<X2  
{ )v1CC..  
}
/p/pVz  
\TUE<<?1s  
} ?+Q$#pb  
sB6dpD  
//线程睡眠 ~:EW>Fq%i  
public static void sleep(int nSecond) ^dfx~C  
{ f;wc{qy  
try{ xr.XU'  
Thread.sleep(nSecond); _f3 WRyN0  
} (Y2mmd  
catch(Exception e) .T$D^?G!D  
{ 13a(FG  
e.printStackTrace (); (a }J$:
 
} vbp-`M
(  
} ;v_V+t<$  
O:^'x*}  
//日志 j#VIHCzlr  
public static void log(String sMsg) wbi3lH:;  
{ U^rm:*f  
System.err.println(sMsg); Sl>>SP  
} _!!}'fMC  
EZib1g&:R/  
?'sXgo.}  
public static void log(int sMsg) 9tk" :ld  
{ .45^=2NGmQ  
System.err.println(sMsg); +j[`,5oS  
} :Q-oV8t{  
} d0 -~|`5  
@]=f?+y[ 2  
HE;V zR  
/* ZXt?[Ll  
**TestMethod.java :}9j^}"c3  
*/ /K|:9Q$K6  
package NetFox; nm@']  
%!y89x=E  
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2  
public class TestMethod { TJOvyz`t  
AIh*1>2Xn  
_faJB@a_  
public TestMethod() \zu}\{  
{ ///xx/weblogic60b2_win.exe =j~Q/-`EC0  
try{ =Ndli>x}1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +O+<Go@a  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); V"#Jk!k9k  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Au5rR>W  
fileFetch.start(); 6peyh_  
} 2
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catch(Exception e){e.printStackTrace ();} .X
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'7tBvVO_  
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} T'1gy}  
`FJ|W6%  
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public static void main(String[] args) vZkXt!%)  
{ |nY~ZVTt/  
new TestMethod(); &U"X$aFc  
} Np2ci~"<
.  
} )X5(#E  
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