http断点续传简单实现（java)

/* !6:q#B*  
**SiteFileFetch.java <,S0C\la=  
*/ #UN(R  
package NetFox; F
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import java.io.*; {V& 2k9*  
import java.net.*; ;0}8vs  
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public class SiteFileFetch extends Thread { -e_+x'uF  
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SiteInfoBean siteInfoBean = null; //文件信息Bean a$p2I+lX
 
long[] nStartPos; //开始位置 5- Q`v/w;  
long[] nEndPos; //结束位置 5BKmp-m  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [,_M@g3  
long nFileLength; //文件长度 zdA:K25"  
boolean bFirst = true; //是否第一次取文件 0`X%&  
boolean bStop = false; //停止标志 Zp|LCE"  
File tmpFile; //文件下载的临时信息 xNt  
DataOutputStream output; //输出到文件的输出流 x/$s:[0B#  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <@CBc:j0  
public SiteFileFetch(SiteInfoBean bean) throws IOException @Kri)U i
 
{ 7pNTCZY|  
siteInfoBean = bean; qL^}t_>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); SM:SxhrGt  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); M%7H-^{  
if(tmpFile.exists ()) \~xOdqF/  
{ ?v2OoNQ   
bFirst = false; @URLFMFi  
read_nPos(); SEY  
} nLq7J:  
else ?U0iHg{  
{ T6f{'.w  
nStartPos = new long[bean.getNSplitter()]; sY,!Ir`/`  
nEndPos = new long[bean.getNSplitter()]; (^g?/i1@d  
} +j5u[X  
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} z;x`dOP  
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public void run() D%LM"p  
{ uPe4Rr  
//获得文件长度 96F:%|yG  
//分割文件 ~4Is   
//实例FileSplitterFetch okX\z[X  
//启动FileSplitterFetch线程 fiTMS:  
//等待子线程返回 R~b9)  
try{ sZ-]yr\E"  
if(bFirst) -5\aL"?4  
{ ,TU!W|($  
nFileLength = getFileSize(); sTqy-^e7  
if(nFileLength == -1) 1G|Q~%cv  
{ %dZD;Vhg  
System.err.println("File Length is not known!"); w;Qo9=-  
} /#$bb4  
else if(nFileLength == -2) fDq, )~D  
{ ac.O#6&  
System.err.println("File is not access!"); #I@]8U#,":  
} sXTt)J  
else 4:cbasy  
{ L4sN)EI  
for(int i=0;i<nStartPos.length;i++) o<-%)#e  
{ #s1M>M)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @Risabn  
} *6*#"#D  
for(int i=0;i<nEndPos.length-1;i++) X5wS6v)#(  
{ P0Na<)\'Y!  
nEndPos = nStartPos[i+1]; CV4V_G  
} L5yxaF{]  
nEndPos[nEndPos.length-1] = nFileLength; 1s\10 hK1c  
} 1:7>Em<s  
} o;Zoj}  
`#fOY$#XB  
CpS'2@6  
//启动子线程 w0SzK-&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; TFxb\  
for(int i=0;i<nStartPos.length;i++) NOx&`OU
+  
{ .EloBP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), F.A<e #e?
 
nStartPos,nEndPos,i); ;~]&$2sk  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K?[pCF2C  
fileSplitterFetch.start(); 'n:Ft  
} j)-D.bY0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @+1E|4L1vf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9b]U&A$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", no?)GQ  
nEndPos = " + nFileLength); @hzQk~Gdi  
// fileSplitterFetch[nPos.length-1].start(); xxkP4,(p  
#j-,#P@  
~n[LL)v  
//等待子线程结束 {]<D"x;  
//int count = 0; qoZ*sV  
//是否结束while循环 +1d\ZZA|6&  
boolean breakWhile = false; +ZRsa`'^  
TP{a*ke^5,  
=_":Z!_  
while(!bStop) }#'KM
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{ MruWt*  
write_nPos(); mApn(&  
Utility.sleep(500); 2zFdKs,  
breakWhile = true; u~s'<c+8_  
Z
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for(int i=0;i<nStartPos.length;i++) ]3={o3[:  
{ M8[YW|VkP  
if(!fileSplitterFetch.bDownOver) "[[fQpe4@  
{ $#RD3#=?u  
breakWhile = false; do[K-r  
break; J$e.$ah;  
} o B6"D  
} # Jdip)  
if(breakWhile) :ZL>JVk  
break;
l*v([@A\  
,6M-xSDs  
s`#hk^{  
//count++; raqLXO!j  
//if(count>4) d:pp,N~2o  
// siteStop(); 5)nv  
} NWAF4i
&$  
EPa3Yb?BGb  
Y43#];  
System.err.println("文件下载结束！"); m
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} w4x8 Sre  
catch(Exception e){e.printStackTrace ();} pRU6jV 6e)  
} '|d (<.[  
3Aj_,&X.@(  
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//获得文件长度 O]Kb~jkd  
public long getFileSize() tLvli>y@  
{ /ruf1?\,R  
int nFileLength = -1; %eV`};9  
try{ %'=oMbi>i4  
URL url = new URL(siteInfoBean.getSSiteURL());  Nl_;l  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D{
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httpConnection.setRequestProperty("User-Agent","NetFox"); =d5!O~}r>  
:jUuw:\  
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int responseCode=httpConnection.getResponseCode(); Vks,3$  
if(responseCode>=400) L3GJq{t  
{ 3?%kawO&  
processErrorCode(responseCode); )I>rC%2P  
return -2; //-2 represent access is error m
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} UpIf t=@P  
7S1!|*/ I  
U3V<ITZI8t  
String sHeader; :9`1bZ?a  
=#^dG''*"  
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for(int i=1;;i++) SW; bE  
{ ZH}NlEn  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 41zeN++  
//Utility.log(in.readLine()); ho20>vw#  
sHeader=httpConnection.getHeaderFieldKey(i); 0*AlLwO  
if(sHeader!=null) up1aFzY|6x  
{ AO]lXa  
if(sHeader.equals("Content-Length")) |X.z|wKT6  
{ nB]Q^~jX  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8;'n.SC{  
break; *Qf}4a0  
} Y
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} <R(2 9QN  
else P X0#X=$  
break; -J30g\  
} y?JbJ  
} i3"sArP"|  
catch(IOException e){e.printStackTrace ();} {S}@P~H=  
catch(Exception e){e.printStackTrace ();} q kKABow  
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Utility.log(nFileLength); <
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return nFileLength; ul%bo%&~  
} L%0lX$2&\  
/t
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:acQK=fe  
//保存下载信息（文件指针位置） !kcg#+s91  
private void write_nPos() ~"m
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{ 2o$8CR;  
try{ +o3g]0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Z:v1?v  
output.writeInt(nStartPos.length); :=Q|gRTL*  
for(int i=0;i<nStartPos.length;i++) 16>uD;G  
{ oB\Xl)A<  
// output.writeLong(nPos);
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output.writeLong(fileSplitterFetch.nStartPos); xAjQW=  
output.writeLong(fileSplitterFetch.nEndPos); SRTpE,  
} [:QMn
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output.close(); nX~MoWH1  
} :#/bA&  
catch(IOException e){e.printStackTrace ();} E5(Y*m!  
catch(Exception e){e.printStackTrace ();} Wj:QC<5 v  
} )^\='(s  
x/7G0K2\}  
?lK!OyCkc  
//读取保存的下载信息（文件指针位置） ay_D.gxz  
private void read_nPos() m%[t&^b}T  
{ =5ih,>>g  
try{ FZ9<Q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g#4gGhI  
int nCount = input.readInt(); gQuw|u  
nStartPos = new long[nCount]; ?iX=2-  
nEndPos = new long[nCount]; !_9$[Oq~  
for(int i=0;i<nStartPos.length;i++) Uot-@|l  
{ `
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nStartPos = input.readLong(); j/<y  
nEndPos = input.readLong(); xp&!Cl>C3\  
} Zir`IQ$  
input.close(); <L~xR5  
} XijLS7Aw|  
catch(IOException e){e.printStackTrace ();} ~vGtNMQg  
catch(Exception e){e.printStackTrace ();} RfBb{?PP)  
} ~TH5>``;gF  
fmJWd|  
@MB _gt)7?  
private void processErrorCode(int nErrorCode) 4w( vR
e  
{ $NT9LtT@K  
System.err.println("Error Code : " + nErrorCode); tb0E?&M  
} N1~V +_mM  
D:E~yh)$-  
0f%:OU5Y  
//停止文件下载 X`n0b<  
public void siteStop() <83gn :$  
{ ;q; C^l  
bStop = true; `4H9f&8(  
for(int i=0;i<nStartPos.length;i++) Qe$>Jv5  
fileSplitterFetch.splitterStop(); K$cIVsfr  
" ^baiN@ac  
'd^gRH<z  
} aNC,ccm  
} 5TneuGD  
//负责部分文件的抓取 +n[wkgFd  
**FileSplitterFetch.java !t Oky  
*/ 6KCmswvE  
package NetFox; *+j{9LK  
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cIvYfgIo9  
import java.io.*; YC&jKx.>  
import java.net.*; B21AcE  
@JEmybu  
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public class FileSplitterFetch extends Thread { :6$4K"^1  
(+LR u1z  
4l}M i  
String sURL; //File URL N>fYH.c3Y  
long nStartPos; //File Snippet Start Position 1m`tqlFU9  
long nEndPos; //File Snippet End Position g!
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int nThreadID; //Thread's ID n [Xzo}  
boolean bDownOver = false; //Downing is over oPu|Q^I=  
boolean bStop = false; //Stop identical V$<G)dwUG5  
FileAccessI fileAccessI = null; //File Access interface zQ5jx5B":  
z8(R.TB  
F|Dz]ar  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /QXs-T}d  
{ '?G[T28  
this.sURL = sURL; 3y=<w|4F  
this.nStartPos = nStart; Q^Z<RA(C  
this.nEndPos = nEnd; c =N]! ,MO  
nThreadID = id; *_<*bhR<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 to!W={S<ol  
} <,pLW~2-"  
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public void run() <`xRqe:&9  
{ HS`bto0*  
while(nStartPos < nEndPos && !bStop) \8*,&ak%  
{ #1't"R+3M  
5d?!<(e6  
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try{ }C{}oLz  
URL url = new URL(sURL); # 5f|1O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [ lzy &To  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]EM)_:tRf  
String sProperty = "bytes="+nStartPos+"-"; H@2v<e@  
httpConnection.setRequestProperty("RANGE",sProperty); #HM\a  
Utility.log(sProperty); L_gsG|xX  
)YnI!v2T  
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InputStream input = httpConnection.getInputStream(); Wl !!5\  
//logResponseHead(httpConnection); ^KZAYB9C  
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XW~ BEa  
byte[] b = new byte[1024]; EK8
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int nRead; \Qi#'c$5+a  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Xrj(,
|  
{ < R|)5/9  
nStartPos += fileAccessI.write(b,0,nRead); M8?#%x6;N  
//if(nThreadID == 1) cPx~|,)l  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d
7gH3 l  
} A)RI:?+  
Y*kh$E%<#  
FU5LYXCs  
Utility.log("Thread " + nThreadID + " is over!");  &6\r  
bDownOver = true; I[g?Ju >  
//nPos = fileAccessI.write (b,0,nRead); urT/+deR  
} n~,]KdU]  
catch(Exception e){e.printStackTrace ();} z^P* :  
} Pu$kj"|q*[  
} j$|j8?  
4aalhy<j  
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//打印回应的头信息 =wIdC3Ph  
public void logResponseHead(HttpURLConnection con) C`2*2Y%xkG  
{ y/X:=d6"  
for(int i=1;;i++) Ko$ $dkSE  
{ QDjW!BsX3  
String header=con.getHeaderFieldKey(i); FtFv<UV  
if(header!=null) %UUp=I  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); W(&Go'9e"  
Utility.log(header+" : "+con.getHeaderField(header)); FI?gT  
else ]^
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break; *`+<x  
} L876$  
} {WYu0J@  
6z9R1&~%  
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public void splitterStop() IS,zy+w  
{ ;#Jq$v)D  
bStop = true; d,Cz-.'sOf  
} P\q<d  
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|t4Gz1"q=8  
} 4i_spF-3  
!paN`Fz\a  
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/* n0+g]|a AF  
**FileAccess.java P9 {}&z%:  
*//文件访问(定位，写) zB#_:(1qK  
package NetFox; :LZ-da"QR  
import java.io.*; LN@E\wRw{r  
N{1.gS  
FF%\gJ  
public class FileAccessI implements Serializable{ 0Y5LDP  
gt =j5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 r/mA2  
RandomAccessFile oSavedFile; 8%;}LK  
long nPos; E fP>O  
IvEMg2f}  
%^a]J"Ydi8  
public FileAccessI() throws IOException pT("2:)x  
{ /^++As0pY  
this("",0); aL8p"iSG9  
} TpJg-F  
ZB~l2  
dV5P
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public FileAccessI(String sName,long nPos) throws IOException 2wB.S_4"-<  
{ u iBl#J Q  
oSavedFile = new RandomAccessFile(sName,"rw"); p+orBw3  
this.nPos = nPos; 5~@?>)TBv  
oSavedFile.seek(nPos); ;\<""Yj@l  
} |RR"'o_E  
J"%8:pL  
! 9d_Gf-  
public synchronized int write(byte[] b,int nStart,int nLen) G;2R]H#p  
{ XOu+&wOu  
int n = -1; H"#)&a7  
try{ n11LxGwk  
oSavedFile.write(b,nStart,nLen); 1i4WWK7k  
n = nLen; h7bPAW=(  
} <_"B}c/2$  
catch(IOException e) %9t{Z1$  
{ f"vk# 3  
e.printStackTrace (); _,DO~L  
} }sf YCz  
}TSgAwsbC  
Kb^>X{  
return n; vTpStoUM  
} fx<FIj7  
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t:\l&R&  
} GHv{   
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ID)^vwn  
/* `-4'/~G  
**SiteInfoBean.java (jMtN?&0H-  
*/ DH:J  
package NetFox; dw~[9oh  
ypH8QfxLTr  
(VR"Mi4  
public class SiteInfoBean { |)9thIQF  
#S%4?  
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private String sSiteURL; //Site's URL XcOA)'Py  
private String sFilePath; //Saved File's Path BU!#z(vU  
private String sFileName; //Saved File's Name 4avc=Y5  
private int nSplitter; //Count of Splited Downloading File M~als3  
Q8;#_HE  
gc##V]OD  
public SiteInfoBean() @|BD|{k  
{//nSplitter的缺省值为5 ,I ZqLA  
//default value of nSplitter is 5 0x\2#i  
this("","","",5); cA<<&C  
} rOW;yJ[  
}g>kpa0c  
{-HDkG' 8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fe|g3>/|  
{ _lXt8}:+  
sSiteURL= sURL; !x7o|l|cP  
sFilePath = sPath; !n eo\  
sFileName = sName; |=O1Hn  
this.nSplitter = nSpiltter; JT04vm4  
RwW$O@0  
A;,Dg=FL/  
} f3G1r5x  
'G8 ?'u_)  
}S*/b1  
public String getSSiteURL() X]!D;7^  
{ W .U+.hR  
return sSiteURL; }z wX  
} ys%zlbj[  
m2(E>raV6  
:k~dj C  
public void setSSiteURL(String value) ox[ .)v  
{ oSY7IIf%L  
sSiteURL = value; y@3Q;~l,  
} n3$gx,KL  
3CM^j<9  
[/cIUQ  
public String getSFilePath() Yl~$V(  
{ Jt]&;0zn2  
return sFilePath; -w]/7cH  
} w>[T&0-N  
Ns<?b;aK  
&RW`W)
0;  
public void setSFilePath(String value) W pN.]x  
{ 2 z7}+lH  
sFilePath = value; \0?$wIH?  
} U;U08/y  
O9^T3~x[V  
 WK==j1  
public String getSFileName() XQ?fJWLU  
{ 
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return sFileName; ,?(ciO)  
} xQU"A2{}>  
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t'g^W  
public void setSFileName(String value) @h}`DNaZ^  
{ <6jFKA<  
sFileName = value; mI"D(bx\  
} _Yq@FOu  
ORBxD"J&  
%(<(Y  
public int getNSplitter() Fp%Ln(/m  
{ Y:psZ  
return nSplitter; _ym"m,,7?  
} VEs5;]#<2D  
rF] +,4  
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public void setNSplitter(int nCount) +sf .PSz$  
{ c}-(.eu  
nSplitter = nCount; dJD(\a>r.u  
} W5SNI>|E  
} 89HsPB1"t  
3^wC<ZXcD  
ER^QV(IvP8  
/* o
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**Utility.java q3h'l,  
*/ $1Z6\G O  
package NetFox; A@$kLex  
rs]I  
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public class Utility { -RMi
8{  
<)U4Xz?  
U|5-0u5  
public Utility() 6BAW  
{ fS=hpL6]@  
(Rd$VYuf  
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H  
} ;Vu5p#,O<M  
41Ve}%  
//线程睡眠 4kl Ao$  
public static void sleep(int nSecond) BKIjNV3  
{ )Gk`[*q ;  
try{ )T|L,Lp  
Thread.sleep(nSecond); Eu,`7iQ?(  
} ,6,]#R :J  
catch(Exception e) fex,z%}p  
{ 9P WY52!  
e.printStackTrace (); BRv x[u  
} x#H 3=YD*  
} GP
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/*rht
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//日志 u2iXJmM*  
public static void log(String sMsg) V/%~F6e  
{ ~Z)/RT/  
System.err.println(sMsg); szmmu*F,U:  
} 5@!st  
OW@\./nM  
w_wslN,)  
public static void log(int sMsg) 7cTk@Gq  
{ ]$b2a&r9  
System.err.println(sMsg); ~nY]o"8
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} K8I$]M  
} `[fxyg:u  
vbG]mMJ  
"TOa=Tt{,  
/* {XCf-{a]~  
**TestMethod.java tJ0NPI56yP  
*/ +&=?BC}L9^  
package NetFox; WyhhCR=;  
0JjUAxNq  
WT\<.Py  
public class TestMethod { Af(WV>'  
z@ 35NZn  
(5Nv8H8|  
public TestMethod() {y)s.b~JB  
{ ///xx/weblogic60b2_win.exe X[yNFW}S2W  
try{ vX|UgK?2^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /~p+j{0L3W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Wr?'$:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); c3TKl/  
fileFetch.start(); !ZXUPH  
} ]/X(V|t  
catch(Exception e){e.printStackTrace ();} '@nbqM  
\;X+X,M  
5 `/< v^  
} *# {z3{+  
KzUlTl0  
RO(TvZ0pE  
public static void main(String[] args) ;3eKqr0  
{ TI|/u$SJ<Z  
new TestMethod(); 5VW|fI  
} #U mF-c  
} *iA4:EIP  
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