http断点续传简单实现（java)

/* @JE:\  
**SiteFileFetch.java Yi&;4vC  
*/ V\%;S  
package NetFox; f!e8xDfA  
import java.io.*; #>O,w0<qM  
import java.net.*; Wra*lQb/B  
#nX0xV5=  
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public class SiteFileFetch extends Thread { n_AW0i.  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Hs~M!eK  
long[] nStartPos; //开始位置 _Akc7"  
long[] nEndPos; //结束位置 ,ZV<o!\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象
_s (0P*  
long nFileLength; //文件长度 4O9HoX#-?  
boolean bFirst = true; //是否第一次取文件 7xB#)o53  
boolean bStop = false; //停止标志 QE)I7(  
File tmpFile; //文件下载的临时信息 T,Cq;|g5E  
DataOutputStream output; //输出到文件的输出流 =t<!W  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） B~-VGT2o  
public SiteFileFetch(SiteInfoBean bean) throws IOException ch1EF/"  
{ ./jkY7 k  
siteInfoBean = bean; +cheLc  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~xGWL%og  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); HcUiv
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if(tmpFile.exists ()) 8|{:N>7  
{ X}0NeG^'O  
bFirst = false; @jN!j*Y H  
read_nPos(); yopEqO  
} ?0hk~8c  
else zN#$eyt  
{ 7on$}=%  
nStartPos = new long[bean.getNSplitter()]; ]o$Kh$~5  
nEndPos = new long[bean.getNSplitter()]; 5dT-{c%w4  
} Dd<gYPC  
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} IpGq_TU  
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public void run() Y<:%_]]  
{ 44f8Hc1g  
//获得文件长度 n0 _:!]k^  
//分割文件 *W y0hnr;]  
//实例FileSplitterFetch [WXtR  
//启动FileSplitterFetch线程 :RzcK>Gub=  
//等待子线程返回 qnyFRPC  
try{ Se*ZQtwE  
if(bFirst) mV@.JFXKP  
{ "Vho`x3  
nFileLength = getFileSize(); y^Oj4Y:  
if(nFileLength == -1) G'

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{ FlOKTY  
System.err.println("File Length is not known!"); 5aL0N  
} zv <,  
else if(nFileLength == -2) Of7j~kdh83  
{ ggVB8QN{  
System.err.println("File is not access!"); $n(?oyf  
} g}{Rk>
k  
else ]n${j/x  
{ GuQ3$B3j  
for(int i=0;i<nStartPos.length;i++) 7XT2d=)"  
{ BqvOi~l  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )_NQ*m  
} FfI$3:9  
for(int i=0;i<nEndPos.length-1;i++) D*Siy;  
{ \! Os!s  
nEndPos = nStartPos[i+1]; DC]FY|ff  
} g v&xC 6>  
nEndPos[nEndPos.length-1] = nFileLength; +z+25qWi  
} <\8dh(>  
} Yt++?  
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93kSBF#  
//启动子线程  h#^I
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #AyM!  
for(int i=0;i<nStartPos.length;i++) @bmu4!"d  
{ {[hV['Awv  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f5 wn`a~h  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), hx+a.N
 
nStartPos,nEndPos,i); kMo;<Z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U;i:k%Bzy  
fileSplitterFetch.start(); mJc'oG-  
} P%xk   
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @Q!f^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9j49#wG0"B  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $f_;>f2N  
nEndPos = " + nFileLength); [`=|^2n?  
// fileSplitterFetch[nPos.length-1].start(); ?:s`}b  
zbddn4bW9  
5Jp@n .  
//等待子线程结束 {ogGi/8  
//int count = 0; .oO_x>  
//是否结束while循环 =9i:R!,W  
boolean breakWhile = false; R5X<8(4p  
]Q-ON&/  
#PVgx9T=_  
while(!bStop) ]r$S{<  
{ N
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write_nPos(); w)&]k#r  
Utility.sleep(500); i:&Y{iPQp  
breakWhile = true; ZUQ1\Iw  
~ I]kY%  
H_ .@{8I  
for(int i=0;i<nStartPos.length;i++) 9:!n'mn  
{ KAjKv_6=g  
if(!fileSplitterFetch.bDownOver) Fq&@dxN3  
{ j{7_p$JM  
breakWhile = false; W6K]jIQ  
break; }bIEWho  
} @0A0\2  
} uDa
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if(breakWhile) FGr0W|?v  
break; Fr,>|  
NJz8ANpro$  
=NSLx2:T  
//count++; Z]1~9:7ap  
//if(count>4) rMTtPuc2  
// siteStop(); ZJP.-`U  
}
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b?CmKiM%  
.7g^w+W  
System.err.println("文件下载结束！"); j Z3N+_J1  
} -J:](p  
catch(Exception e){e.printStackTrace ();} @H@&B`Kd  
} e3F)FTG&  
#fG!dD42  
H[*.Jd  
//获得文件长度 .m7iXd{  
public long getFileSize() )cUc}Avg}  
{ bNFX+GA/  
int nFileLength = -1; &Km?(%?  
try{ 59$mfW o>  
URL url = new URL(siteInfoBean.getSSiteURL()); 7_E+y$i=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); e&8pTD3  
httpConnection.setRequestProperty("User-Agent","NetFox"); WWrDr   
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int responseCode=httpConnection.getResponseCode(); .<u<!fL2  
if(responseCode>=400) _66zXfM<  
{ }qc[ysDK]  
processErrorCode(responseCode); H 
}uT'  
return -2; //-2 represent access is error >pv~$  
} 2(5wFc  
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}f^K}*sK$5  
String sHeader;  3i?{E^  
&hB~Z(zS!  
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for(int i=1;;i++) S%Pk@n`z]  
{ [k@D}p x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Gw~
^6(Qu  
//Utility.log(in.readLine()); J^ P/2a#a  
sHeader=httpConnection.getHeaderFieldKey(i); n4>
 
if(sHeader!=null) >`5iq.v  
{ 17$JBQ,[  
if(sHeader.equals("Content-Length")) +_Fsiu_b  
{ =XQ3sk6U  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); n6O1\}YB  
break; !g=
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} UmiW_JB  
} HpDU:m  
else ~b3xn T  
break; zST#X}  
} VXn]*Mo  
} me1ac\  
catch(IOException e){e.printStackTrace ();} p % 3B^  
catch(Exception e){e.printStackTrace ();} %ghQ#dZ]&  
'}P)iS2  
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Utility.log(nFileLength); nl*{@R.q @  
_UjAct]6  
u<!!%C~+=  
return nFileLength; <C+:hsS=  
} &^63*x;hE  
e~'y%|D  
6xk"bIp  
//保存下载信息（文件指针位置） 9{70l539  
private void write_nPos() /-^gK^  
{ *ErTDy(   
try{ aZ*b"3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); U[U$1LSS  
output.writeInt(nStartPos.length); +'uF3-+WY  
for(int i=0;i<nStartPos.length;i++) wC
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{ Z)P x6\?+  
// output.writeLong(nPos); xfkG&&  
output.writeLong(fileSplitterFetch.nStartPos); '[qG ,^f  
output.writeLong(fileSplitterFetch.nEndPos); 'bY^=9&|  
} K&BlWXT  
output.close(); p|(910OEQ  
} X2dTV}~i  
catch(IOException e){e.printStackTrace ();} u-OwL1S+  
catch(Exception e){e.printStackTrace ();} %+gze|J  
} {'"A hiR/  
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//读取保存的下载信息（文件指针位置） o$d;
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private void read_nPos() F8_pwJUpf-  
{ P%'bSx1  
try{ +_:Ih,-   
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0m7J'gm{  
int nCount = input.readInt(); %[lX  H  
nStartPos = new long[nCount]; e>nRJH8pK  
nEndPos = new long[nCount]; ,EcmMI^A  
for(int i=0;i<nStartPos.length;i++) DG7FG--  
{ kVkV~  
nStartPos = input.readLong(); @ewQx|  
nEndPos = input.readLong(); o[+1O  
} v :6`(5  
input.close(); &oTSff>p}  
} [%P_ Y/  
catch(IOException e){e.printStackTrace ();} MA(\r  
catch(Exception e){e.printStackTrace ();} F=iz\O!6  
} 4)JrOe&k  
(LL4V 3)  
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private void processErrorCode(int nErrorCode) jGR_EE  
{ wXuHD<<  
System.err.println("Error Code : " + nErrorCode); TQE3/IL  
} \{{B57/Isq  
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>AN`L`%2  
//停止文件下载 Ulj2Py}  
public void siteStop() / DeIs  
{ EZ1H0fm  
bStop = true; SQ>.P  
for(int i=0;i<nStartPos.length;i++) ~S"G~a(&j  
fileSplitterFetch.splitterStop(); #4%,09+  
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} "E/F{6NH  
} wF?THkdFo  
//负责部分文件的抓取 0@*rp7  
**FileSplitterFetch.java 72~)bu
 
*/ 4xtbP\=
 
package NetFox; }k\a~<'X  
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import java.io.*; #jA|
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import java.net.*; \w^U<_zq  

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public class FileSplitterFetch extends Thread { Iimz  
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String sURL; //File URL D'Byl,W$
 
long nStartPos; //File Snippet Start Position Uk|Xs~@#E  
long nEndPos; //File Snippet End Position d?b2jZ$r]  
int nThreadID; //Thread's ID !x;T2l  
boolean bDownOver = false; //Downing is over [FF%HRce,.  
boolean bStop = false; //Stop identical "LP4)hr_`  
FileAccessI fileAccessI = null; //File Access interface `hM]5;0  
z)43+8;  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (yc$W9  
{ y ?4|jN  
this.sURL = sURL; r A0[y  
this.nStartPos = nStart; a(d'iAU8^  
this.nEndPos = nEnd; 2x$\vL0  
nThreadID = id; (tyo4Tz1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (V{bfDu&h@  
} xx!o]D-}  
{< jLfL1  
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public void run() ]~3wq[O  
{ zHDC8m  
while(nStartPos < nEndPos && !bStop) /A|ofAr)  
{ "^22Y}VB  
si3i#l&.b_  
qi7dcn@d  
try{ ?#pL\1"E  
URL url = new URL(sURL); N<"_5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c)iQ3_&=  
httpConnection.setRequestProperty("User-Agent","NetFox"); >hB]T%'  
String sProperty = "bytes="+nStartPos+"-"; sGMC$%e}  
httpConnection.setRequestProperty("RANGE",sProperty); Be8Gx  
Utility.log(sProperty); t8]u#bx"?  
oo-^BG  
cO)GiWE  
InputStream input = httpConnection.getInputStream(); YDs/BF Z  
//logResponseHead(httpConnection); &rcr])jg[  
*=^
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byte[] b = new byte[1024]; +vDT^|2SF  
int nRead; }-: d*YtK  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) () b0Sh=  
{ <C# s0UX  
nStartPos += fileAccessI.write(b,0,nRead); 1PLKcU  
//if(nThreadID == 1) ~z32%k  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jqb,^T|j;m  
} Zu&trxnNf[  
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.7~Kfm@2  
Utility.log("Thread " + nThreadID + " is over!"); U:_T9!fG  
bDownOver = true; 9dqD(S#C;"  
//nPos = fileAccessI.write (b,0,nRead); n9cWvy&f  
} -}4H'%Z(i  
catch(Exception e){e.printStackTrace ();} Yk?uxZ4)H  
} +-qD!(&-6  
} N|1J@"H  
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//打印回应的头信息 =E4nNL
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public void logResponseHead(HttpURLConnection con) OK3B6T5w=  
{ wT*`Od8w  
for(int i=1;;i++) K# _plpr  
{ C[gSiL  
String header=con.getHeaderFieldKey(i); YJrK oK}  
if(header!=null) 8'`&f&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Vk0O^o  
Utility.log(header+" : "+con.getHeaderField(header)); cf0em!  
else O!Mm~@MoA  
break; Oo rH  
} r8^1JJ~\  
} 7@+0E2'  
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public void splitterStop() 6"&&s  
{ Z;WqKIM#  
bStop = true; g\ <Lb  
} -pg7>vOq  
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} q' _  
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/* ':.d,x)  
**FileAccess.java qDcl;{L  
*//文件访问(定位，写) *2;w;(-s  
package NetFox; Y`lC4*g  
import java.io.*; Mz
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public class FileAccessI implements Serializable{ i}+dctg/  
>OiC].1   
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :Tj,;0#/  
RandomAccessFile oSavedFile; Hej0l^  
long nPos; 4:6@9.VVT  
{/R4Q1  
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public FileAccessI() throws IOException |$bZO`^  
{ |6_<4lmTxF  
this("",0); pjbKMx  
} _|*3uGo:  
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public FileAccessI(String sName,long nPos) throws IOException mRQ F5W6  
{ .0\Wu+  
oSavedFile = new RandomAccessFile(sName,"rw"); y6:=2(]w<p  
this.nPos = nPos; `@Kh>K  
oSavedFile.seek(nPos); {/#?n["  
} atl0#FBd  
&yVii^  
V4VTP]'n  
public synchronized int write(byte[] b,int nStart,int nLen) "8{u_+_B*  
{ QKCk. 0Xe  
int n = -1; y1k""75  
try{ dzbzZ@y  
oSavedFile.write(b,nStart,nLen); CHBCi) '6h  
n = nLen; b%|%Rek8  
} 8V~w3ssz  
catch(IOException e) XPWK"t01  
{ mYa0_P%^  
e.printStackTrace (); We9C9)0  
} HnOp*FP
  

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return n; F Fg0}  
} =(Gv_  
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} 3+n&Ya1  
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/* OmKT}D~ 4  
**SiteInfoBean.java ShGR!r<  
*/ HESwz{eSS  
package NetFox; b?H
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public class SiteInfoBean { r,yhc =  
|? r,W~9`  
].:S!QO  
private String sSiteURL; //Site's URL (M5=8g%>d  
private String sFilePath; //Saved File's Path >@TZYdl  
private String sFileName; //Saved File's Name
!>t|vgW  
private int nSplitter; //Count of Splited Downloading File rJ!xzg
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=A=er1~%  
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public SiteInfoBean() 3(FJ<,"D}  
{//nSplitter的缺省值为5 7%)4cHZ^$?  
//default value of nSplitter is 5 0YIvE\-  
this("","","",5);
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} 7b'XQ/rs  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (h`||48d  
{ gX6'!}G
8]  
sSiteURL= sURL; m_(+-G
  
sFilePath = sPath; WW==  
sFileName = sName; oN)K2&M0  
this.nSplitter = nSpiltter; :X2B+}6_&  
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>@y5R^B`  
} >`s2s@Mx  
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public String getSSiteURL() $&lS7}  
{ h'kgL~+$  
return sSiteURL; #^Sd r-   
} H>_%ZXL  
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public void setSSiteURL(String value) C=9|K`g5 R  
{ ~}wPiu,  
sSiteURL = value; P9Rq'u  
} &t%ICz&3  
|\N[EM%.@  

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public String getSFilePath() 5O*.qp?  
{ BnAia3z  
return sFilePath; 2r[Q$GPM<  
} fqvA0"tv  
N}\$i&Vi  
3go!P])  
public void setSFilePath(String value) ~?[@
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{ F(@|p]3*  
sFilePath = value; p,ZubRJ"  
} l+YpRx/T\  
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w 7=Y_  
public String getSFileName() 37M7bB0  
{ QGLfZvTT  
return sFileName; QD /| zi  
} Y@#~8\_  
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mn 8A%6W  
public void setSFileName(String value) DB%=/ \U  
{ 3(vI{[yhT  
sFileName = value; 4*m\Zoq>  
} E})PNf;  
G^ n|9)CVW  
"o[\Aec:  
public int getNSplitter() .;*0odxv  
{ GytI_an8  
return nSplitter; > -k$:[l  
} \ m2[  
97$y,a{6  
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public void setNSplitter(int nCount) F"a,[i,[W  
{ 1a#wUd3  
nSplitter = nCount; zPhNV8k-  
} Vs9fAAXS4  
} y . AN0  
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/* ilzR/DJMa  
**Utility.java B;?a. 81~  
*/ $,'r} %  
package NetFox; 7xWX:2l*?  
#4~Ivj  
bumS>:
 
public class Utility { ?uh7m2l0D  
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public Utility() uXK$5"  
{ Yxi.A$g  
<0&];5 on  
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} :@YZ6?hf  
i,b>&V/Y$  
//线程睡眠 #(XP=PUj  
public static void sleep(int nSecond) 3MkF  
{ ?i9LqHL  
try{ zb:p,T@5  
Thread.sleep(nSecond); @GjWeOj]  
} p/SJt0  
catch(Exception e) Q,)G_lO  
{ aD%")eP%&  
e.printStackTrace (); X0P<ifIv  
} C]eb=rw$  
} P#76ehR]K  
shP,-Vs#  
//日志 #gi&pR'$  
public static void log(String sMsg) ydoCoD w  
{ u~a<Psp&|  
System.err.println(sMsg); 'nW:2(J  
} #!Kg?BR2  
CX\# |Q8q  
LTFA2X&E=  
public static void log(int sMsg) y{"8VT)  
{ TLO-$>h  
System.err.println(sMsg); 8G(wYlxi  
} ;~xkT'  
} KA%tVBl  
o2F6K*u
}  

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/* zXp{9P\c  
**TestMethod.java LH0\Sm
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*/ 8 I,(\<Xv  
package NetFox; "64pVaT4  
H:p(C?tk{  
fa"eyBO50  
public class TestMethod { E)>6}0P  
u9k##a4.E  
5?6ATP:[  
public TestMethod() -u)06C*39  
{ ///xx/weblogic60b2_win.exe X~n Kuo  
try{ WS2TOAya)  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5E}0
<&  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); q$U;\Mg)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); oX!s u  
fileFetch.start(); -OVJ]  
} CDR^xo5 dP  
catch(Exception e){e.printStackTrace ();} #YjV3O5<  
JWH}0+1*  
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} NoiU5pP  
QWfwoe&;R:  
rpy`Wz/[  
public static void main(String[] args) SE%i@}  
{ Gvj@?62  
new TestMethod(); iTxn  
} =:9n+7~$  
} ;jI\MZ~l\  
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