http断点续传简单实现（java)

/* ?^W1WEBm  
**SiteFileFetch.java H2+b3y-1a]  
*/ imeE&  
package NetFox; ;S '?l
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import java.io.*; .6xMLo,R  
import java.net.*; m(*rMO>_  
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@Z2np{X:  
public class SiteFileFetch extends Thread { ~$J(it-a  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Fxc_s/^=t  
long[] nStartPos; //开始位置 _DH^ K9,9  
long[] nEndPos; //结束位置 ');vc~C  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _+'!l'`  
long nFileLength; //文件长度 m|F1_Ggz  
boolean bFirst = true; //是否第一次取文件 \2e^
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boolean bStop = false; //停止标志 Y
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File tmpFile; //文件下载的临时信息 8B:y46
  
DataOutputStream output; //输出到文件的输出流 M/dgW`c  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^'0N%`bY!  
public SiteFileFetch(SiteInfoBean bean) throws IOException b
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{ WFh.oe8  
siteInfoBean = bean; &i(Ip'r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); _p*8ke  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [`t
;or  
if(tmpFile.exists ()) w2'q9pB+  
{ }#7rg_O]>  
bFirst = false; !Yv_V]u=  
read_nPos(); {;u,04OVK  
} 4P k%+l  
else Z)M "`2Ur  
{ 6UuN-7z!"  
nStartPos = new long[bean.getNSplitter()]; V<W;[#"  
nEndPos = new long[bean.getNSplitter()]; H8FvI"J  
} OyF=G^w  
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} [
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public void run() =g9n =spAn  
{ CTRUr"  
//获得文件长度 G?'^"ae"Z  
//分割文件 XGR2L DR  
//实例FileSplitterFetch $jg[6`L$  
//启动FileSplitterFetch线程 _&hM6N  
//等待子线程返回 f7~dn#<@  
try{ QQ.?A(U7  
if(bFirst) Q_0+N3  
{ XNWtX-[^@  
nFileLength = getFileSize(); 9 A ?{}c  
if(nFileLength == -1) "Zgwe,#  
{ x2"1,1%H7  
System.err.println("File Length is not known!"); x?{UWh%  
} +ig%_QED[\  
else if(nFileLength == -2) >] 'oN  
{ S>~f.  
System.err.println("File is not access!"); UpGDLbf^  
} a31
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else GHcx@||C?  
{ ZyUcL_  
for(int i=0;i<nStartPos.length;i++) ='o3<}  
{ <J&S[`U!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); sX%n`L  
} ju{Y6XJ)  
for(int i=0;i<nEndPos.length-1;i++) [! $NTt_  
{ **hQb$  
nEndPos = nStartPos[i+1]; Kq3c Kp4  
} 51q|-d  
nEndPos[nEndPos.length-1] = nFileLength; ^el+ej/=  
} PR.3EL  
} RVatGa0  
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?IVJ#6[  
//启动子线程 k
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; W\~^*ny P6  
for(int i=0;i<nStartPos.length;i++) q
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{ U|} ?{x  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A9MM^jV8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?uq`|1`  
nStartPos,nEndPos,i); |:1{B1sqA  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kcCCa@~v  
fileSplitterFetch.start(); ^?VQ$o2  
} En
M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A`Z/B[)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1|MRXK  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l*1|B3#m!  
nEndPos = " + nFileLength); 'I]XX==_  
// fileSplitterFetch[nPos.length-1].start(); faQmkO  
p'K`K\X  
7Z< ~{eD,  
//等待子线程结束 arYq$~U  
//int count = 0;  ? }M81  
//是否结束while循环 a `R%\@1  
boolean breakWhile = false; 7Z6=e6/\  
wh8';LZ>R  
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while(!bStop) DzAZv/h76  
{ !T`oHs  
write_nPos();  %!<Y  
Utility.sleep(500); :o'x?]  
breakWhile = true; d
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for(int i=0;i<nStartPos.length;i++) ))"gWO  
{ }|DspO  
if(!fileSplitterFetch.bDownOver) 'C[tPP  
{ m{/7)2.  
breakWhile = false; Hb)FeGsd).  
break; Q\$3l'W  
} ORExI.<`W  
} ;k<dp7^  
if(breakWhile) cM#rus?)+  
break; K zWo}tT  
|toP86  
Cr.YSWg)4  
//count++; !jj`Ht)  
//if(count>4) #EPC]jFk  
// siteStop(); c[h~=0UtJ  
} ]S6Gz/4aV+  
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\9?[|m z  
System.err.println("文件下载结束！"); A8)4nOXM  
} 4>KF`?%4  
catch(Exception e){e.printStackTrace ();} 76nH)^%l<  
} '~[8>Q>  
!}&|a~U@`k  
PYkhY;*  
//获得文件长度 [YDSS/  
public long getFileSize() gEh/m.L7  
{ ] ,|,/~  
int nFileLength = -1; :`bC3Mr  
try{ owAO&"C  
URL url = new URL(siteInfoBean.getSSiteURL()); H[=\_X1o(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D-gH_ff<]9  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4#$#x=:  
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int responseCode=httpConnection.getResponseCode(); =nEP:7~{  
if(responseCode>=400) ^6s im2  
{ `Q@7,z=f  
processErrorCode(responseCode); &.)=>2  
return -2; //-2 represent access is error o@:"3s  
} tB_le>rhl  
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String sHeader; t>j_C{X1(  
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for(int i=1;;i++) `^M]|7  
{ =?i?-6M  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0m@+ &X>w  
//Utility.log(in.readLine()); =*\s`ox`  
sHeader=httpConnection.getHeaderFieldKey(i); t~Q9}+  
if(sHeader!=null) Bkcwl  
{ D!j/a!MaKk  
if(sHeader.equals("Content-Length")) ,.,8-
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{ w~3X m{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xR+vu>f  
break; cO?*(e1m=  
} oi #B7  
} s QDgNJbU  
else ]S2rqKB  
break; #CS>_qe.{  
} ,KY;NbL-Jp  
} T.bFB+'E|  
catch(IOException e){e.printStackTrace ();} N,~O+  
catch(Exception e){e.printStackTrace ();} |$Yk)z3  
@*;x1A-]V  
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Utility.log(nFileLength); <8r"QJY/  
>* -IIo  
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return nFileLength; M.}9)ho   
} @|gG3  
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]kj^T?&n.  
//保存下载信息（文件指针位置） YvY|\2^K  
private void write_nPos() )nm+_U  
{ L%/RD2LD  
try{ w2LnY1A  
output = new DataOutputStream(new FileOutputStream(tmpFile)); TOG:`F
ID  
output.writeInt(nStartPos.length); 6H#:rM  
for(int i=0;i<nStartPos.length;i++) Y\ [|k-6  
{ w{ja*F6  
// output.writeLong(nPos); >S5J^c  
output.writeLong(fileSplitterFetch.nStartPos); UP](1lAf  
output.writeLong(fileSplitterFetch.nEndPos); |<W$rzM  
} /T _M't@j  
output.close(); 1?'4%>kp  
} /~LE1^1&U  
catch(IOException e){e.printStackTrace ();} ,np=m17  
catch(Exception e){e.printStackTrace ();} Ww<Y]H$xZ<  
} h.<f%&)F  
@?B+|*cm  
9o@3$  
//读取保存的下载信息（文件指针位置） ]E9iaq6Z  
private void read_nPos() 4$-R|@,|_  
{ VDxm|7  
try{ 54$^ldD  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?P9aXwc  
int nCount = input.readInt(); d9{lj(2P  
nStartPos = new long[nCount]; f&-`+V}U  
nEndPos = new long[nCount]; ((M,6Q}  
for(int i=0;i<nStartPos.length;i++) yP"2.9\erH  
{ 'FW?   
nStartPos = input.readLong(); 1AJ6NBC&c  
nEndPos = input.readLong(); [-
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} 6,t6~Uo/  
input.close(); (\:Rnl  
} 1/$PxQ  
catch(IOException e){e.printStackTrace ();} IMM;LC%rD9  
catch(Exception e){e.printStackTrace ();} xe@e#9N$  
} poz_=,c  
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private void processErrorCode(int nErrorCode) Tm"H9  
{ I%d=c0>%  
System.err.println("Error Code : " + nErrorCode); ~RR!~q  
} }aWy#Oe  
:9&c%~7B9  
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//停止文件下载 1I%u)[;>  
public void siteStop() GvVkb=="  
{ s^u Y  
bStop = true; V.Hv6  
for(int i=0;i<nStartPos.length;i++) ;yNc7Vl  
fileSplitterFetch.splitterStop(); Sz5t~U=G  
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} ZthT('"a  
} 5kHaZ Q  
//负责部分文件的抓取 UytMnJ88  
**FileSplitterFetch.java H
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*/ t}+/GSwT  
package NetFox; Q}#Je.;  
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import java.io.*; /+*"*Br/  
import java.net.*; ytttF5-  
3d}v?q78  
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public class FileSplitterFetch extends Thread { W )FxN,  
x2!R&q8U>  
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String sURL; //File URL ImN'o4vo  
long nStartPos; //File Snippet Start Position r!R-3LO0s  
long nEndPos; //File Snippet End Position 4aO/^Hl  
int nThreadID; //Thread's ID J,}h{-Xy`  
boolean bDownOver = false; //Downing is over QFP9"FM5F  
boolean bStop = false; //Stop identical 8c5YX  
FileAccessI fileAccessI = null; //File Access interface @!`__>K  
wm~7`&  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3
;>ls~4  
{ Z- feMM  
this.sURL = sURL; xF8r+{_J)  
this.nStartPos = nStart; 01A{\O1$j  
this.nEndPos = nEnd; R'Jrbe|  
nThreadID = id; kY)Vr3uGA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 JL6$7h  
} ](Fey0@  
]PS`"o,pF$  
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public void run() ABCm2$<  
{ 6?a`'&  
while(nStartPos < nEndPos && !bStop) -#Zvj
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{ Qu|CXUk  
1_+ h"LE  
@j|E"VYY  
try{ ZDW9H6ux  
URL url = new URL(sURL); ht
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @j\:K<sk  
httpConnection.setRequestProperty("User-Agent","NetFox"); `w!XO$"]Z  
String sProperty = "bytes="+nStartPos+"-"; gGrVpOzBj  
httpConnection.setRequestProperty("RANGE",sProperty); I[?\Or  
Utility.log(sProperty); $7q3[skH  
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InputStream input = httpConnection.getInputStream(); oxxuw Dcl  
//logResponseHead(httpConnection); bv4umL /  
^L%_kL_7  
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byte[] b = new byte[1024]; n{gEIUo
#  
int nRead; q%sZV>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) lE
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{ 9L>?N:%5  
nStartPos += fileAccessI.write(b,0,nRead); COw"6czX/  
//if(nThreadID == 1) T8+[R2_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i.E2a)  
} %axr@o[  
${T/b(NM  
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Utility.log("Thread " + nThreadID + " is over!"); gWr7^u&q@|  
bDownOver = true; 'WW:'[Syn'  
//nPos = fileAccessI.write (b,0,nRead); @} Ig*@  
} cQEUHhRg!  
catch(Exception e){e.printStackTrace ();} FI^Wh7J  
} #QwkRzVoy  
} %5e|  
c!\Gj|  
*^-AOSVt,  
//打印回应的头信息 a&'9[9E1  
public void logResponseHead(HttpURLConnection con) |.)LZP,  
{ :qE.(k1@5  
for(int i=1;;i++) z|>TkCW6  
{ y-hTTd"{  
String header=con.getHeaderFieldKey(i); AqgY*"A7  
if(header!=null) >/n];fl>8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8"&!3_  
Utility.log(header+" : "+con.getHeaderField(header)); d2
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else nI3p`N8j*  
break; *'?ZG/ (  
} mz0{eO  
} f\ P0%  
k{2Gq1S{  
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public void splitterStop() >`
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{ s&$?m[w  
bStop = true; T
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} P&Keslk  
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} &. =8Q?  
> 'R{,1# U  
7n5gXiI"  
/* 9G[ DuYJI  
**FileAccess.java h~#iGs  
*//文件访问(定位，写) #&.Znk:@.f  
package NetFox; toA}0MI(:  
import java.io.*; y_9\07va<  
Z=&|__+d  
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public class FileAccessI implements Serializable{ v-#,@&Uwq  
)+L|<6JXA  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 AGFA;X  
RandomAccessFile oSavedFile; 54p{J  
long nPos; Z'i@;^=A  
+QN4hJK  
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public FileAccessI() throws IOException myj/93p}`b  
{
20}HTV{v  
this("",0); >*EZZ\eU!  
} $q\"d?n  
{<{VJGY7T  
8-<F4^i_i  
public FileAccessI(String sName,long nPos) throws IOException yhKH} kR  
{ uUjjAGZ  
oSavedFile = new RandomAccessFile(sName,"rw"); J'2 Yrn  
this.nPos = nPos; |YLja87  
oSavedFile.seek(nPos); wS=vm}}u  
} fnX[R2KZ  
fd4gB6>  
B :%Vq2`  
public synchronized int write(byte[] b,int nStart,int nLen) 43k'96[2d  
{ l0'Yq%Nf  
int n = -1; Nk@-yZ@,8  
try{ Mst%]@TG  
oSavedFile.write(b,nStart,nLen); }-tJ.3Zw  
n = nLen; >12jUm)  
} 8)S)!2_h  
catch(IOException e) N'y<<tTA
 
{ ?pIELezfK  
e.printStackTrace (); H@-q NjM  
} 8Ay7I  
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s={>{,E  
return n; YH58p&up  
} ,Mw93Kp Va  
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*w;?&)8%  
} m%.4OXX"&  
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/* ~2>Adp  
**SiteInfoBean.java j)/Vtf  
*/ 8Ze> hEG  
package NetFox; ,~cK]!:>s  
Y*@7/2,  
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public class SiteInfoBean { oQ,n?on  
A o*IshVh  
(LsVd2Ab
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private String sSiteURL; //Site's URL _b8KK4UR  
private String sFilePath; //Saved File's Path #jBmWaP.  
private String sFileName; //Saved File's Name D 6'd&U{_  
private int nSplitter; //Count of Splited Downloading File ;uAh)|;S#  
n`^
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7W}%ralkg  
public SiteInfoBean() {*bx8*y1  
{//nSplitter的缺省值为5 {$EX :ID  
//default value of nSplitter is 5 Re~6'  
this("","","",5); s:'>G;p  
} f-#:3k*7S  
D)G oWt  
}o]}R#|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) U{
dK8~  
{ :V6 [_VaF  
sSiteURL= sURL; $G <r2lPy  
sFilePath = sPath; Ru d9l.n  
sFileName = sName; q/:]+  
this.nSplitter = nSpiltter; :kcqf,7  
W2h*t"5W  
[[_>DM  
} 8r>\scS  
UQkd$w<  

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public String getSSiteURL() >#n"r1  
{ dSjO12b  
return sSiteURL; w)J-e gc  
} YL`MLt4MC  
kt`ln  
:!Z|_y{b  
public void setSSiteURL(String value) q8ZxeMqx%  
{ r[):'ys,C  
sSiteURL = value; a(IE8:yU`  
} ;\pINtl9<  
&b~X&{3,  
D4"<suU|.  
public String getSFilePath() cl#XiyK>  
{ i+QVs_jW  
return sFilePath; C:&Sk\   
} 3Yx'/=]  
[x?9<#T  
!m=Js"  
public void setSFilePath(String value) | J'k9W"  
{ @fA|y  
sFilePath = value; :xmj42w>^  
} iiuT:r  
V!*1F1  
o S{hv:
)>  
public String getSFileName() (MqQ3ys  
{ r9-ayp#pC  
return sFileName; X9c<g;  
} 731RqUR  
j+fF$6po#t  
VJA/d2Oys  
public void setSFileName(String value) AEf[:]i]  
{ l'Li!u  
sFileName = value; NG\'Ii:-J  
} e|SNb*_  
o=7e8l  
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public int getNSplitter() ~f[;(?39xZ  
{ DdISJWc'`5  
return nSplitter; 37IHn6r\  
} v0!(&g3Sd  
q$H@W.f  
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public void setNSplitter(int nCount) [".94(qs  
{ ze LI
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nSplitter = nCount; ME)='~E  
} $t6t 6<M)  
} HdY#cVxy  
R:'&>.AUw  
5KTFf6Uq  
/* 4y4r;[@U  
**Utility.java <%|u1cn~!v  
*/ k^KpQ&n  
package NetFox; j)nE!GKD(  
Mj2Dat`p9  
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public class Utility { kE+fdr\ T  
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_BgWy#  
public Utility() b9wC:NgQx  
{ ^%6f%]_  
+?QHSIQo  
VgY6M_V  
} q)@;8Z=_c  
c/F!cW{z^  
//线程睡眠 -J'k
ed  
public static void sleep(int nSecond) pp#!sRUKPV  
{ Xrc{wDn  
try{ -nD}k  
Thread.sleep(nSecond); FyXO @yF  
} WU/5i 8  
catch(Exception e) hp7ni1V  
{ *.A-UoHa  
e.printStackTrace (); 8MU7|9 Q  
} BHkicb?   
} @C('kUX~!  
!6#.%"{-  
//日志 -EU=R_yg  
public static void log(String sMsg) )\W}&9 >  
{ 6Y.k<oem  
System.err.println(sMsg); U(~Nmo'  
} *y+K{ fM1  
ignOF  
^4[QX -_2  
public static void log(int sMsg) ~dgFr6  
{ VVuNU"-  
System.err.println(sMsg); f*m^x7  
} I;<__  
} \f]w'qiW5  
!WB3%E,I  
C.}ho.} r  
/* !QqVJ a{j  
**TestMethod.java w8KxEV=  
*/ ;?-{Uk  
package NetFox; E1A5<^t  
O|9Nl*rXz  
q}E'x/s2m  
public class TestMethod { ?H{?jJj$H  
ds2xl7jg  
:efDPNm5  
public TestMethod() Tjj27+y*\  
{ ///xx/weblogic60b2_win.exe )"00fZL  
try{ QdD@[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >RiU/L
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~X;sa,)L1+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); K|;L{[[yH  
fileFetch.start(); <BdC#t:*L  
} '&]6(+I>  
catch(Exception e){e.printStackTrace ();} d%!yFix;<  
L<Z2  
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} g ZES}]N  
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public static void main(String[] args) o 7V&HJ[  
{ 5["n] i  
new TestMethod(); ((BdT:T\_  
} pC&i!la{o}  
} 09iD| $~  
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