http断点续传简单实现（java)

/* jK[~dY
  
**SiteFileFetch.java /GzA89N(  
*/ t3~ZGOn  
package NetFox; Mn-f  
import java.io.*; =`8%qh  
import java.net.*; #hA]r.  
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| JmEI9n2  
public class SiteFileFetch extends Thread { aaN|g{pX  
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SiteInfoBean siteInfoBean = null; //文件信息Bean syEWc(5  
long[] nStartPos; //开始位置 R3HfE*;Z  
long[] nEndPos; //结束位置 qhKW6v  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B{#
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long nFileLength; //文件长度 ,9(=Iu-?1  
boolean bFirst = true; //是否第一次取文件 EXdx$I=X  
boolean bStop = false; //停止标志 rRTAWAs%T  
File tmpFile; //文件下载的临时信息 8y<NT"  
DataOutputStream output; //输出到文件的输出流 0>  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） QbF!V%+a's  
public SiteFileFetch(SiteInfoBean bean) throws IOException h83;
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{ 'u
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siteInfoBean = bean; &0E>
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *u2pk>y)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v4?qI >/  
if(tmpFile.exists ()) "kLu]M<  
{ '|zkRdB*Lq  
bFirst = false; 's.cwB: #  
read_nPos(); 7XZ5CX&  
} $\W|{u`  
else  #E[{  
{ 6D[m}/?Uy  
nStartPos = new long[bean.getNSplitter()]; uafSz@`  
nEndPos = new long[bean.getNSplitter()]; IC
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} Ez3>}E,  
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} i2a""zac  
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public void run() >S3,_@C  
{ G_fP%ovh  
//获得文件长度 Dr;-2$Kt/&  
//分割文件 U"1z"PcV  
//实例FileSplitterFetch c$cb2V7,  
//启动FileSplitterFetch线程 c.-/e u^|  
//等待子线程返回 #].n0[  
try{ R]0p L   
if(bFirst) `N+A8  
{ bNUb  
nFileLength = getFileSize(); Hs%;uyI@$  
if(nFileLength == -1) cULASS`,  
{ a(+.rf;  
System.err.println("File Length is not known!"); ?2Q9z-$  
} tBtG- X2  
else if(nFileLength == -2) &f}a`/{@  
{ ZnX]Q+w  
System.err.println("File is not access!"); *W'F6Hpu  
} a3&&7n  
else 2"31k2H[  
{ y"|QY!fK  
for(int i=0;i<nStartPos.length;i++) <<43'N+  
{ nqG9$!k^t  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); C'HW`rh.^  
} C%s+o0b  
for(int i=0;i<nEndPos.length-1;i++) uF xrv  
{ :
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nEndPos = nStartPos[i+1]; .'zXO  
} ~16QdwK  
nEndPos[nEndPos.length-1] = nFileLength; 0K\Xxo.=  
} TM|M#hMS  
} ?tWcx;h:>  
<A"T_Rk  
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//启动子线程 ?o@5PL  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  E*[dc  
for(int i=0;i<nStartPos.length;i++) ;Up'+[Vj'C  
{ ~m ,xG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zp"Lp>i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )!h(oR  
nStartPos,nEndPos,i); `rt  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |5uvmK  
fileSplitterFetch.start(); ;Z\1PwT  
} jOJ$QT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X!}
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); w"s;R8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %M=[h2SN  
nEndPos = " + nFileLength); m5O;aj* i  
// fileSplitterFetch[nPos.length-1].start(); v/n4Lp$W^  
-E6#G[JJ  
(1~d/u?2\  
//等待子线程结束 7 Jxhn!  
//int count = 0; sV8}Gv a  
//是否结束while循环 XcOfQs  
boolean breakWhile = false; AXUSU(hU  
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while(!bStop)  oCE=!75  
{ Vy]y73~  
write_nPos(); Vej [wY-c  
Utility.sleep(500); pwg$% lv  
breakWhile = true; X?,ly3,  
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for(int i=0;i<nStartPos.length;i++) \)\uAI-  
{ LRF_w)^['  
if(!fileSplitterFetch.bDownOver) X<\E 'v`~  
{ !PQ%h/ix  
breakWhile = false;  %2 A-u  
break; M2K{{pGJ[&  
} E5a1 7ra  
} q=NI}k  
if(breakWhile) i/ED_<_Vg  
break; 0GUm~zi1  
s@USJ4#  
l)V!0eW  
//count++; bSOxM/N  
//if(count>4) gbb2!q6p  
// siteStop();  %+\ PN  
} ==zt)s.G(+  
=oN(1k^  
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System.err.println("文件下载结束！"); ,EkzBVgo  
} W[pOLc
-  
catch(Exception e){e.printStackTrace ();} I r8,=
 
} .hBq1p  
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//获得文件长度 BMubN   
public long getFileSize() ~%SmH[i  
{ uvNLm]*  
int nFileLength = -1; XRZj+muTZ  
try{ 6f
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URL url = new URL(siteInfoBean.getSSiteURL()); l(c2 B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q5[x2 s_d  
httpConnection.setRequestProperty("User-Agent","NetFox"); :O`7kZ]=n  
~d0:>8zQR  
4*k>M+o/C4  
int responseCode=httpConnection.getResponseCode(); ~UrKyA  
if(responseCode>=400) l@;UwnI  
{ ^$8@B]*  
processErrorCode(responseCode); @DiXe[kI  
return -2; //-2 represent access is error J1i{n7f=@  
} t)#8r,9c  
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[I*)H7pt}  
String sHeader; w %4SNR  
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for(int i=1;;i++) ?vmu,y  
{ SM57bN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }ufzlHD  
//Utility.log(in.readLine()); W<f-  
sHeader=httpConnection.getHeaderFieldKey(i); gN,O)@N'd3  
if(sHeader!=null) &cZQ,o  
{ ,;3bPjey  
if(sHeader.equals("Content-Length")) QO1pwrX<  
{ dTV4 Q`Z  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F$L2bgQR?'  
break; 1NHiW v  
} I5nxY)v  
} j,DF' h  
else jL9g.q4^  
break; o#"U8N%r  
} KCBA`N8  
} L/ L#[  
catch(IOException e){e.printStackTrace ();} z7vc|Z|  
catch(Exception e){e.printStackTrace ();} 5j8aMnvs  
/ .wO<l=  
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Utility.log(nFileLength); Sb2hM~  
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return nFileLength; Hw0S/ytY  
} M~rN17S  
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//保存下载信息（文件指针位置） ]=gNA  
private void write_nPos() tTjadnX  
{ y?6J%~\WP  
try{ \ltbiDP2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -yP|CZM  
output.writeInt(nStartPos.length); ~Q+E""  
for(int i=0;i<nStartPos.length;i++) ;;4>vF#*  
{ '99rXw  
// output.writeLong(nPos); Zz,j,w0 Z  
output.writeLong(fileSplitterFetch.nStartPos); d}RU-uiW  
output.writeLong(fileSplitterFetch.nEndPos); O]-)?y/  
} ZVelKI8>  
output.close(); ABx< Ep6  
} lfJvN  
catch(IOException e){e.printStackTrace ();} c -sc*.&  
catch(Exception e){e.printStackTrace ();} 8+* 1s7{  
} v}cTS@0  
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>(?}'pS8  
//读取保存的下载信息（文件指针位置） !W\za0p  
private void read_nPos() o+],L_Ab  
{ {yzo#"4Oy  
try{ |o@xWs@m  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ub,5~I+`  
int nCount = input.readInt(); ,`pUz[wl  
nStartPos = new long[nCount]; n 3eLIA{  
nEndPos = new long[nCount]; x/S:)z%X  
for(int i=0;i<nStartPos.length;i++) mm dQ\\  
{ WMw|lV r  
nStartPos = input.readLong(); C vOH*K'  
nEndPos = input.readLong(); >g>L>{  
} T1-.+&<  
input.close(); \ u*R6z  
} [ML|,kq!  
catch(IOException e){e.printStackTrace ();} ;aj4V<@  
catch(Exception e){e.printStackTrace ();} .OM^@V~T  
} op2<~v0?  
>;K!yI?0  
"Wb>y*S   
private void processErrorCode(int nErrorCode) Q4Zw<IZv5  
{ H2jF=U"=  
System.err.println("Error Code : " + nErrorCode);  *Cj<Vy  
} g1H$wU3eu  
APJVD-  
!MyCxM6  
//停止文件下载 iW?z2%#  
public void siteStop() qg06*$%  
{ ip+?k<]z  
bStop = true; Leu93f2  
for(int i=0;i<nStartPos.length;i++) &cpqn2Z  
fileSplitterFetch.splitterStop(); -=InGm\Y  
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9Ro7xSeD  
} 3j6Am{9  
} D_Zt:tzO  
//负责部分文件的抓取 )p`zN=t
 
**FileSplitterFetch.java <~bvfA=  
*/ ;%Zu[G`C  
package NetFox; Z#t}yC%^d  
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import java.io.*; [BTOs4f  
import java.net.*; "Ng%"N
z  
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public class FileSplitterFetch extends Thread { M:*)l(  
u.@B-Pf[Eo  
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String sURL; //File URL gSk0#Jt  
long nStartPos; //File Snippet Start Position w }=LC#le  
long nEndPos; //File Snippet End Position pf`vH`r  
int nThreadID; //Thread's ID XS(Q)\"  
boolean bDownOver = false; //Downing is over .)c+gyaQ  
boolean bStop = false; //Stop identical M^&^g  
FileAccessI fileAccessI = null; //File Access interface 2{xf{)hO?  

sh/4ui{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException B'-n ^';  
{ 8\S$iGd  
this.sURL = sURL; s^"*]9B"  
this.nStartPos = nStart; zXW)v/ ZD  
this.nEndPos = nEnd; &a
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nThreadID = id; a|-ozBFR  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1wy?<B.f
 
} ~,Kx"VK  
cB6LJ}R  
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public void run() AQGl}%k_  
{ XI>HC'.0  
while(nStartPos < nEndPos && !bStop) $}JWJ\-]  
{ >x*ef]aS  
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try{ w\1K.j=>|N  
URL url = new URL(sURL); lNo]]a+_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x"P@[T  
httpConnection.setRequestProperty("User-Agent","NetFox"); qK)T#sh  
String sProperty = "bytes="+nStartPos+"-"; g
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httpConnection.setRequestProperty("RANGE",sProperty); zwJ\F '  
Utility.log(sProperty); /[I#3|  
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InputStream input = httpConnection.getInputStream(); !8*7{7  
//logResponseHead(httpConnection); }_oQg_-7e  
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byte[] b = new byte[1024]; wln"g,ct  
int nRead; v(]dIH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) y`Zn{mQ@[  
{ kA/yL]m^S  
nStartPos += fileAccessI.write(b,0,nRead); :{ Lihe~\  
//if(nThreadID == 1) ^g=j`f[T  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6eQa@[.Q  
} !l$k6,WJi  
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Utility.log("Thread " + nThreadID + " is over!"); 0*,]`A=  
bDownOver = true; $"g'C8  
//nPos = fileAccessI.write (b,0,nRead); M7=|N:/_  
} nP0rg  
catch(Exception e){e.printStackTrace ();} +t8#rT ^B  
} A3.*d:A  
} n^Q-K}!T/  
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//打印回应的头信息 tu^C<MV  
public void logResponseHead(HttpURLConnection con) G%>{Z?!B  
{ t;}`~B  
for(int i=1;;i++) Uka(Vr:  
{ qb$M.-\ne  
String header=con.getHeaderFieldKey(i); $U"pdf  
if(header!=null) W)AfXy  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :)F0~Q  
Utility.log(header+" : "+con.getHeaderField(header)); '>GPk5Nq77  
else Q[9W{l+  
break; _~ 3r*j  
} A&{eC C  
} v}.~m)  
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public void splitterStop() $ncP#6  
{ XrJLlH>R4  
bStop = true; )3ZkKv;zY  
} a28`)17z  
[&)*jc16  
@+sYwlA~  
} SP;1XXlL  
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/* &
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**FileAccess.java P"|-)d  
*//文件访问(定位，写) ri49r*_1  
package NetFox; 6('CB|ga  
import java.io.*; T2TWb  
w3M F62:  
2LS91  
public class FileAccessI implements Serializable{ 
t')%;N  
>VJ"e`  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;Q<2Y#  
RandomAccessFile oSavedFile; D2f~*!vEnA  
long nPos; UYGO|lkEU  
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public FileAccessI() throws IOException /d>Jkv  
{ p-h(C'PqF  
this("",0); NYeL1h)l  
} :ay`Id_tm  
]?_V+F  
Ue=1NnRDkA  
public FileAccessI(String sName,long nPos) throws IOException cHJ4[x=  
{ Wf=hFc1_@  
oSavedFile = new RandomAccessFile(sName,"rw"); |N|[E5Cn  
this.nPos = nPos; b@B\2BT  
oSavedFile.seek(nPos); d!y_N&z|(  
} tcD5"ALJ  
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:/6u*HwZh  
public synchronized int write(byte[] b,int nStart,int nLen) >fp_$bjd  
{ VqS1n  
int n = -1; :q$.=?X3  
try{ %1rN6A!%  
oSavedFile.write(b,nStart,nLen); ,qIut|C*  
n = nLen; eIbz`|%3  
} 8COGe=+o  
catch(IOException e) >[<f\BN|  
{ (R!`Z%  
e.printStackTrace (); ,#hNHFa'JH  
} )!5"\eys  
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#6
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return n; nMOXy\&mI  
} n66b(6"mO2  
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} c LfPSA  
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/*
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**SiteInfoBean.java 6>[J^k%~w)  
*/ CIQ9dx7>  
package NetFox; G5UNW<P2C  
v
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public class SiteInfoBean { uCj)7>}v{M  
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private String sSiteURL; //Site's URL +XAM2uN5_.  
private String sFilePath; //Saved File's Path fwSI"cfM  
private String sFileName; //Saved File's Name RA}Y$}^#'  
private int nSplitter; //Count of Splited Downloading File `rpmh7*WV  
alyA#zao|  
&&Otj-n5  
public SiteInfoBean() wpOM~!9R  
{//nSplitter的缺省值为5 @"afEMd  
//default value of nSplitter is 5 tY60~@YO&  
this("","","",5); wdRk+  
} l?KP/0`  
$Q`\-  
X + B=?|M  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \n-.gG  
{ 2lxA/.f  
sSiteURL= sURL; Rc}#4pM8  
sFilePath = sPath; 3
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sFileName = sName; G$jw#a[L  
this.nSplitter = nSpiltter; gh%Q9Ni-  
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} 2'8I/>-  
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+[#^c3x2  
public String getSSiteURL() N._^\FRyn  
{ (n2=.9k!  
return sSiteURL; [L?WM>]%  
} VQbKrnX  
/Mw0<#  
oMKGM@V  
public void setSSiteURL(String value) WISeP\:^  
{ *-s':('R  
sSiteURL = value; +`TwBN,kp-  
} o6 8;-b'n  
\ZC0bHsA  
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public String getSFilePath() /re0"!0y  
{ Jg@eGs\*  
return sFilePath; ORt)sn&~d  
} Fb^,%K:  
8CRwHDB  
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public void setSFilePath(String value) ^Fwdi#g  
{ 8%;]]{(B  
sFilePath = value; D`PA
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} LP}j0)n  
VB~Do?]*k%  
3MoVIf1  
public String getSFileName() yXro6u?
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{ r?WOum  
return sFileName; UL3u2g;d  
} e_llW(*l8^  
#G("Oh  
jC'Diu4|Q  
public void setSFileName(String value) 5,du2  
{ "SV/'0  
sFileName = value; jo"zdb  
} nc:K!7:  
#|6M*;lN|  
J_&G\b.9/  
public int getNSplitter() {Yv5Z.L&(  
{ I_na^sh*  
return nSplitter; ^/7Y3n!|3  
} a7e.Z9k!  
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public void setNSplitter(int nCount) ]Waa7)}DM  
{ hJ(S]1B~G  
nSplitter = nCount; M1XzA `*  
} +  $/mh  
} eX o@3/  
ksQw
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/* 34qfP{9!N  
**Utility.java !p3vnOX6  
*/ Xl/2-'4  
package NetFox; 19i[DR  
\`YV)"y" ~  
fCi1JH;  
public class Utility { `^ uX`M/  
Wp
//SV  
\PK}4<x}  
public Utility() u=sZFr@m[  
{ 6"La`}B(T8  
%>,Kd6bdg  
\_|r>vQ  
} JPkI+0  
kSO:xS0 _N  
//线程睡眠 ?^ `EI}g  
public static void sleep(int nSecond) Med0O~T%  
{ $%5!CD1)  
try{ DZV U!J  
Thread.sleep(nSecond); oqy}?<SQ  
} Q5tx\GE  
catch(Exception e) e`Tssa+  
{ =kn-F T  
e.printStackTrace (); \>  
} jR{Rd}QtQ  
} p}h9>R  
rTM0[2N  
//日志 o`\@Yq$.  
public static void log(String sMsg) (?~*.g!  
{ [2nP
r^  
System.err.println(sMsg); (J`EC  
} *@[+C~U  
6q~*\K
Rk
 
CL"q"  
public static void log(int sMsg) (W_U<~`t  
{ &(rR
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System.err.println(sMsg); Z_[jah  
} TXK82qTdf  
} R5MY\^H/A  
{&.?u1C.\  
4$8\IJ7G  
/* S{c;n*xf  
**TestMethod.java 0vcM+}rw  
*/ 3H@29TrJ+  
package NetFox; e"voXe  
ph=U<D4  
bd3q207>  
public class TestMethod { S&;D  
|=ljN7]!  
nWv6
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public TestMethod() M7SVD[7~HM  
{ ///xx/weblogic60b2_win.exe uzWz+atH  
try{ G>0hi1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); IP l]$j>N  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); VHTr;(]hk  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +v"%@lC};  
fileFetch.start(); q<wQ/m  
} 1<3!  
catch(Exception e){e.printStackTrace ();} v6+<F;G3y>  
wM&W
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?K^~(D8(  
} 2^=.jML[  
nAW`G'V#  
D^\2a;[AxA  
public static void main(String[] args) XLsOn(U\&  
{ doV+u(J~  
new TestMethod(); $7bux1L  
} glP W9q,f  
} pt- 1>Ui  
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