http断点续传简单实现（java)

/* A%Ao yy4E  
**SiteFileFetch.java jtA Yp3M-$  
*/ @0aUWG!k  
package NetFox; $0WAhq  
import java.io.*; ^+pmZw90  
import java.net.*; mZORV3bN  
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public class SiteFileFetch extends Thread { btee;3`  
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SiteInfoBean siteInfoBean = null; //文件信息Bean |_-FQ~Hf F  
long[] nStartPos; //开始位置 [scPs,5Y  
long[] nEndPos; //结束位置 ,Ti#g8j  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .NabK  
long nFileLength; //文件长度 U7Ps2~x3  
boolean bFirst = true; //是否第一次取文件 :Y"f.>  
boolean bStop = false; //停止标志 4ed( DSN  
File tmpFile; //文件下载的临时信息 qsJo)SA  
DataOutputStream output; //输出到文件的输出流 KzhldMJ^zq  
@wB$qd;v  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） O,7P6  
public SiteFileFetch(SiteInfoBean bean) throws IOException #<)u%)`  
{ EF}Z+7A  
siteInfoBean = bean; \wMr[_LW  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); H>VuUH|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); S\Q/ "Y  
if(tmpFile.exists ()) TkK- r(=  
{ M6?*\9E  
bFirst = false; H4)){\  
read_nPos(); "g0Ln5&  
} f9!wO';P6  
else ~6R| a  
{ |n0 )s% 8`  
nStartPos = new long[bean.getNSplitter()]; !Y5O3^I=u  
nEndPos = new long[bean.getNSplitter()]; m'Wz0b^BO  
} I'C{=?  
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} 9c<lFZb;  
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public void run() 5pz%DhjLo  
{ .F9>|Xx[  
//获得文件长度 D\>CEBt  
//分割文件 Wh"oL;O  
//实例FileSplitterFetch
!\CoJ.5=  
//启动FileSplitterFetch线程 .aF+>#V=Q  
//等待子线程返回 s fazrz`h  
try{ m39 `f,M  
if(bFirst) >Efv?8$E\  
{ 7\5;;23N4  
nFileLength = getFileSize(); ]^"*Fdn  
if(nFileLength == -1) i9_ZK/*  
{ qbmy~\ZY  
System.err.println("File Length is not known!"); t(^c]*r~  
} S.BM/M  
else if(nFileLength == -2) 1S<V,9(  
{ OLlNCb#t  
System.err.println("File is not access!"); HA>b'lqBM  
} wR1M_&-s  
else (@mvNlc:  
{ ?-Fp rC  
for(int i=0;i<nStartPos.length;i++) ?~;G)5  
{ ~[Mm0L}8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); GYZzWN}U  
} (@~d9PvB>  
for(int i=0;i<nEndPos.length-1;i++) JZ'`.yK:  
{ MJb!+E+  
nEndPos = nStartPos[i+1]; yX?& K}JI  
} RD<l<+C^~  
nEndPos[nEndPos.length-1] = nFileLength; UuW"  
} }_Jr[ia
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} h0L*8P`t  
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[<7Hy,xr_  
//启动子线程 cOq^}Ohan  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]_@5LvI  
for(int i=0;i<nStartPos.length;i++) W& w-yZ  
{ pX+`qxF\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y;4nIWe JL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O:WFh;c  
nStartPos,nEndPos,i); ,vl][MhM  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \XD&0inv  
fileSplitterFetch.start(); _m#M^<0n  
} 6MqJy6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \|RP-8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); LS*^TA(I[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", E$T)N U\  
nEndPos = " + nFileLength); OpA
  
// fileSplitterFetch[nPos.length-1].start(); q3#07o_dV  
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//等待子线程结束 s`U.h^V  
//int count = 0; q0,Diouq  
//是否结束while循环 vE
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boolean breakWhile = false; L]I)E`s  
5v<BB`XWp  
C AVqjT7  
while(!bStop) ^W{+?q'  
{ iZyhj%#  
write_nPos(); LcI,Dy|P  
Utility.sleep(500); -$!`8[fM  
breakWhile = true; ayTEQS  
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for(int i=0;i<nStartPos.length;i++) HeCQF=
R  
{ B0T[[%~3M  
if(!fileSplitterFetch.bDownOver) =
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{ -y;SR+  
breakWhile = false; 3XjM@D  
break; Ox#%Dm2  
} ^&>(_I\w.6  
} UEbRg =6  
if(breakWhile) F 0q#.   
break; +q[puFfl  
;9MsV.n  
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//count++; ,Y6Me+5B  
//if(count>4) v,#*%Gn`%  
// siteStop(); ZnVi.s~1V  
} pj4M|'
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System.err.println("文件下载结束！"); zc%#7"FM  
} &W)Lzpx8c  
catch(Exception e){e.printStackTrace ();} : z*OAl"  
} t
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//获得文件长度 SRuNt3wW6  
public long getFileSize()  BR;f!  
{ l$=Y(Xk  
int nFileLength = -1; n@r'b{2;l  
try{ Q[O[,Rk  
URL url = new URL(siteInfoBean.getSSiteURL()); F?TxViL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z6#}6Y{  
httpConnection.setRequestProperty("User-Agent","NetFox"); L?T%;VdG'>  
wyvrNru<l4  
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int responseCode=httpConnection.getResponseCode(); O:3LA-vA  
if(responseCode>=400) ~OO&%\$k  
{ {PZNJ 2~  
processErrorCode(responseCode); {L^b['h@  
return -2; //-2 represent access is error K"B2 SsC  
} #&a-m,Y$sx  
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String sHeader; PZmg7N  
/2Q@M>  
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for(int i=1;;i++) u?6L.^Op  
{ gx~79;6  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {U/a h2*  
//Utility.log(in.readLine()); 0 UdAF  
sHeader=httpConnection.getHeaderFieldKey(i); b.V\EOk  
if(sHeader!=null) :I*G tq   
{ 7)aitDD  
if(sHeader.equals("Content-Length")) o\6A]T=R  
{ f.SV-{O_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); uH1%diL^  
break; f Glvx~  
} JsAl;w  
} 1ga.%M*  
else w],+lN;  
break; Y?G\@6  
} $J}d6%   
} -?{bCq  
catch(IOException e){e.printStackTrace ();} 2~<N  
catch(Exception e){e.printStackTrace ();} z=C'qF`  
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Utility.log(nFileLength); _EMq"
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return nFileLength; g$
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} A<-Prvryt  
+iKs)s_~  
r;m_@*]  
//保存下载信息（文件指针位置） V8AF;1c?-'  
private void write_nPos() CZaUrr  
{ evOyTvc  
try{ pt[H5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); MR:GH.uM:  
output.writeInt(nStartPos.length); mqxgrb7  
for(int i=0;i<nStartPos.length;i++) T4MB~5,i  
{ ~gU.z6us  
// output.writeLong(nPos); >b9nc\~  
output.writeLong(fileSplitterFetch.nStartPos); ]*b}^PQM^  
output.writeLong(fileSplitterFetch.nEndPos); )Lt|]|1B{  
} ~a@O1MB  
output.close(); 1 ?X(q  
} @n<y[WA  
catch(IOException e){e.printStackTrace ();} L,G{ t^j  
catch(Exception e){e.printStackTrace ();} Ucnj7>+"  
} Hjl{M>z  
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//读取保存的下载信息（文件指针位置） 1NJ,If]  
private void read_nPos() [4Tiukk(  
{ 5cLq6[uO  
try{  Z
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !J<}=G5  
int nCount = input.readInt(); {c5%.<O  
nStartPos = new long[nCount]; m?LnO5Vs  
nEndPos = new long[nCount]; Gd^K,3:. T  
for(int i=0;i<nStartPos.length;i++) LvP{"K;   
{ I{>U7i 5  
nStartPos = input.readLong(); N$#518  
nEndPos = input.readLong(); 4-lG{I_S:  
} 9e^H
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input.close(); $x_6 .AOZ,  
} _m3}0q  
catch(IOException e){e.printStackTrace ();} ch2Qk8  
catch(Exception e){e.printStackTrace ();} llG^+*Y8t  
} .-Y3oWV  
!=%E&e]  
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private void processErrorCode(int nErrorCode) XP#j9CF#.  
{ g-B~"tp  
System.err.println("Error Code : " + nErrorCode); dV+%x"[:  
} ki/xo^Y2<  
b'i-/l$  
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//停止文件下载 2de[ yz  
public void siteStop() 3a#X:?  
{ fwvPh&U&  
bStop = true; N^i<A2'6S;  
for(int i=0;i<nStartPos.length;i++) }~gBnq_DDU  
fileSplitterFetch.splitterStop(); S0X%IG  
E+XpgR
5  
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} rKZ1 c,y  
} Bl,rvk2  
//负责部分文件的抓取 Fqtgw8  
**FileSplitterFetch.java c*0pF=3  
*/ T(UdV]~]"  
package NetFox; -9Iz$(>a  
I_vPGafMx  
;Y:_}kN8_  
import java.io.*; c,WRgXL  
import java.net.*; ZM)YRdh  
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public class FileSplitterFetch extends Thread { :^ 9sy  
&{#4^.Q  
bcgh}D  
String sURL; //File URL f"^G\  
long nStartPos; //File Snippet Start Position "6.JpUf  
long nEndPos; //File Snippet End Position PbR6>'  
int nThreadID; //Thread's ID X6_m&~}15  
boolean bDownOver = false; //Downing is over UdBP2lGd  
boolean bStop = false; //Stop identical bj6-0`  
FileAccessI fileAccessI = null; //File Access interface Ie3 F  
H
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#ma#oWqF}  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8<cD+Jtj  
{ *eE&ptx1  
this.sURL = sURL; K@ZK@++  
this.nStartPos = nStart; :]?y,e%xu,  
this.nEndPos = nEnd; SSi-Z  
nThreadID = id; ~(%TQY5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {+Rf?'JZH  
} ^1d"Rqtv  
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public void run() +APf[ZpU  
{ I]S8:w![  
while(nStartPos < nEndPos && !bStop) %lL^[`AR  
{ mDn*
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try{ JryCL]  
URL url = new URL(sURL); eURy]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]k2Jf}|  
httpConnection.setRequestProperty("User-Agent","NetFox"); jI`1>>N&1  
String sProperty = "bytes="+nStartPos+"-"; 3$YgGum  
httpConnection.setRequestProperty("RANGE",sProperty); caA>; +aBH  
Utility.log(sProperty); tx-HY<  
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InputStream input = httpConnection.getInputStream(); n0o'ns  
//logResponseHead(httpConnection); /.leY$  
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byte[] b = new byte[1024]; C %l!"s^  
int nRead; KH4 5A'o  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) f< A@D"m/  
{ A0x"Etbw)  
nStartPos += fileAccessI.write(b,0,nRead); |T53m;D  
//if(nThreadID == 1) 9Q 4m9}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >eHSbQu/Bu  
} zE"ME*ou  
}Qj
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Utility.log("Thread " + nThreadID + " is over!"); Nr.maucny  
bDownOver = true; b_Us%{  
//nPos = fileAccessI.write (b,0,nRead); CTu#KJ?j  
} I`%\ "bF@  
catch(Exception e){e.printStackTrace ();} A aLj.HR  
} "^
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} fJ!i%</V  
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//打印回应的头信息 d ]LF5*i  
public void logResponseHead(HttpURLConnection con) 5B+>28G%  
{ >
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for(int i=1;;i++) _c}@Fi+E  
{ FU-YI"  
String header=con.getHeaderFieldKey(i); ;
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if(header!=null) ZVo%ssVt  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); chjXsq#Q^  
Utility.log(header+" : "+con.getHeaderField(header)); -eKi}e  
else FI,>v`  
break; P19nF[A  
} E|u#W3-:  
} ~GL"s6C$`;  
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&V;^xMO!  
public void splitterStop() 8nOMyNpy~M  
{ ,Y~{RgG  
bStop = true; np|3 os  
} r3a$n$Qw  
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} hQ!slO  
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/* K9v@L6pY=  
**FileAccess.java hX#s3)87  
*//文件访问(定位，写) J)O1)fR  
package NetFox; 3eUTV<!  
import java.io.*; nBs%k!RR  
qx0RCP /s  
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public class FileAccessI implements Serializable{ Yk',a$.S  
]"SH pq  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2ye^mJ17  
RandomAccessFile oSavedFile; w3lR8R]  
long nPos; 5IeF |#g  
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public FileAccessI() throws IOException <1tFwC|4BJ  
{ *hI  
this("",0); A|sTnhp~  
}
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public FileAccessI(String sName,long nPos) throws IOException [uxhdR`T  
{ wT?.Mte  
oSavedFile = new RandomAccessFile(sName,"rw"); &Mz3CC6  
this.nPos = nPos; eto3dJ!R  
oSavedFile.seek(nPos); g0ec-  
} /60`
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fI"q/+  
public synchronized int write(byte[] b,int nStart,int nLen) sY__ak!>  
{ ~2xC.DF_N  
int n = -1; Pf s_s6  
try{ *0ZL@Kw  
oSavedFile.write(b,nStart,nLen); j&(2ze:=*$  
n = nLen; ]_NN,m>z  
} l,Un7]*  
catch(IOException e) JpN]j`  
{ EL+6u>\-k  
e.printStackTrace (); %V-\|cw   
} &.ZW1TxE8  
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2 g"_
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return n; 910Ym!\{:  
} O[Xl*9P  
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} |fdr\t#'~  
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/* ,eq[X\B>  
**SiteInfoBean.java +5Z0-N@  
*/ o)'u%m  
package NetFox; $ wGDk
  
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/G$8j$  
public class SiteInfoBean { 9"_JiX~3  
Ws?BAfP  
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private String sSiteURL; //Site's URL {GDMix  
private String sFilePath; //Saved File's Path (j8tdEt  
private String sFileName; //Saved File's Name :+ksmyW  
private int nSplitter; //Count of Splited Downloading File Tj@}O:q7:  
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public SiteInfoBean() 
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{//nSplitter的缺省值为5 %]%.{W\j3  
//default value of nSplitter is 5 \&\_[y8U  
this("","","",5); BQVpp,]  
} Mw!?2G[|  
[ P\3XSR  
>B$ZKE  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) A+%oE  
{ ty]JUvR@  
sSiteURL= sURL; \Ku=a{Ne  
sFilePath = sPath; bHcb+TR3  
sFileName = sName; b u%p,u!
 
this.nSplitter = nSpiltter; 'U]= T<
 
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} DZ~w8v7V  
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public String getSSiteURL() 3/8o)9f.  
{ DQW^;Ls  
return sSiteURL; 6Uq@v8mh  
} quc?]rb  
vPEL'mw/3#  
[0CoQ5:d?&  
public void setSSiteURL(String value) b)@%gS\F  
{ GL&ri!,  
sSiteURL = value; f9H;e(D9]  
} ]d?`3{h9LD  
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public String getSFilePath() vC~];!^  
{ [7B:{sH  
return sFilePath; $wU.GM$t~  
} c38RE,4U  
}Q_IqI[7  
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public void setSFilePath(String value) FT73P0!8.  
{ i_ws*7B<  
sFilePath = value; z<c^<hE:l  
} /3:R{9S%  
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public String getSFileName() I_.(&hMn  
{ e8gJ }8Fj  
return sFileName; s$6zA j!  
} o%h"gbvMY!  
a*hOT_;#  
Yo;/7gG>  
public void setSFileName(String value) Cl[ '6Lk  
{ o!L1Qrh  
sFileName = value; `;WiTE)&)  
} Z `O.JE  
/%}+FMj  
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public int getNSplitter() w=d#y )
1  
{ 8lI#D
)}  
return nSplitter; mk_cub@  
} 7{f&L'  
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public void setNSplitter(int nCount) Xtbuy/8"1  
{ qu BTRW9  
nSplitter = nCount; Lx,"jA/  
} l5Z=aW Q  
} 2NAGXWE  
cyA|6Ltg%  
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/* }!\NdQs  
**Utility.java E4[ |=<  
*/ Xhtc0\0"(  
package NetFox; 1;3oGuHj8  
[&t3xC,  
@=`Dw/13  
public class Utility { CCfuz
&  
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2\l7=9 ]\3  
public Utility() Z"'rc.>a  
{ [VIdw92  
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} GjE/!6b  
|M#b`g$JO,  
//线程睡眠 P482D)  
public static void sleep(int nSecond) iN+Dmq5  
{ LP_d}ve  
try{ W+BM|'%}|  
Thread.sleep(nSecond); N}nU\e6 Y  
} f'F:U^  
catch(Exception e) 5p"n g8nR  
{ #9O *@  
e.printStackTrace (); u$[ '}z0:  
} GZ/.eYE  
} vmJ1-<G4*  
~6.AE/ow  
//日志 fF[n?:VV  
public static void log(String sMsg) |TF,Aj  
{ qqT6C%Q`kG  
System.err.println(sMsg); hD{+V!{  
} B<DvH"+$  
l@Ma{*s6=5  
&WN4/=QW-J  
public static void log(int sMsg) b
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{ /@R|*7K;9  
System.err.println(sMsg); _o~<f)E[9  
} <8Nh dCO6  
} }|H]>U&  
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v3[Z]+ ]  
/* ,& =(DJ  
**TestMethod.java M|?qSFv:  
*/ (FbqKx'uq  
package NetFox; 8U0y86q>)E  
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public class TestMethod { R!W!8rr3  
gSEj/
?  
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public TestMethod() f"xi7vJv!f  
{ ///xx/weblogic60b2_win.exe jIK*psaV  
try{ YKf,vHau  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); T({:Y. A;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /u!I2DF  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,d)!&y  
fileFetch.start(); hEsCOcEG  
} Z66akr  
catch(Exception e){e.printStackTrace ();} r1EccY  
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} !1C3{  
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public static void main(String[] args) JTNQz  
{ E{^*^+c"h  
new TestMethod(); B@HW@j  
} }DxXt  
} *r
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