http断点续传简单实现（java)

/* dRXrI  
**SiteFileFetch.java 5O:4-}hz  
*/ OA&r8WK3  
package NetFox; 7O'u5N  
import java.io.*; G%SoC  
import java.net.*; Ft?Yc 5  
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public class SiteFileFetch extends Thread { p+^K$w^Cs  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 3PaMq6Ca  
long[] nStartPos; //开始位置 82yfPQ&UI  
long[] nEndPos; //结束位置 *xDV8iu_  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 E^x/v_,$w!  
long nFileLength; //文件长度 e}2[g  
boolean bFirst = true; //是否第一次取文件 gyOAvx  
boolean bStop = false; //停止标志 <P-AlHYV-  
File tmpFile; //文件下载的临时信息 -5,+gakSk  
DataOutputStream output; //输出到文件的输出流 sJm v{wM  
<(BIWm*  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ])vqXjN6"  
public SiteFileFetch(SiteInfoBean bean) throws IOException 8hZc#b;  
{ ,A>cL#Oe  
siteInfoBean = bean; yUg'^SEbLk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )4jS}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @Qd5a(5WM  
if(tmpFile.exists ()) s"X0Jx}
 
{ H=*2A!O[_  
bFirst = false; {&pBy  
read_nPos(); ,-1d2y  
} M0woJt[&  
else .Iv`B:4  
{ $QaEU="Z  
nStartPos = new long[bean.getNSplitter()]; S vW{1  
nEndPos = new long[bean.getNSplitter()]; h`Xl~=
 
} xhncQhf\  
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} cEEnR1  
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public void run() KqWO9d?w.  
{ Q-||A  
//获得文件长度 W ZW:q  
//分割文件 EP6@5PNZ  
//实例FileSplitterFetch p I@!2c:}  
//启动FileSplitterFetch线程 ,Un
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//等待子线程返回 q5>!.v   
try{ |6
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if(bFirst) ^aY,Wq  
{ }\vw>iHPX@  
nFileLength = getFileSize(); Gvquv\  
if(nFileLength == -1) jgT *=/GH2  
{ K#]FUUnj=  
System.err.println("File Length is not known!"); ]9hhAT44  
} /rv=mlpRL  
else if(nFileLength == -2) c5t7X-LB  
{ 4J$dG l#f  
System.err.println("File is not access!"); lt#3&@<v  
} cd)}a_9  
else }*vO&J@z  
{ g
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for(int i=0;i<nStartPos.length;i++) x24&mWgU  
{ nT@FSt  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I
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} =_`cY^ib+  
for(int i=0;i<nEndPos.length-1;i++) Zu/1:8x  
{ Z xR  
nEndPos = nStartPos[i+1]; zq]:.s  
} 8%^W<.Y  
nEndPos[nEndPos.length-1] = nFileLength; r&nEM6  
} -p f9Wk  
} x.>[A^  
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MDfC%2Q  
//启动子线程 u{|^5%)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; mlbSs_LT^  
for(int i=0;i<nStartPos.length;i++) d&%}u1 .  
{ 0Yfz?:
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), #=I5_
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), u7bji>j  
nStartPos,nEndPos,i); 
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kl#)0yqN0  
fileSplitterFetch.start(); oNRp  
} p+Icq!aH5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
iL3k8:x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); T0K*!j}O  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4,:)%KB"V  
nEndPos = " + nFileLength); \w2X.2b.F  
// fileSplitterFetch[nPos.length-1].start(); {e83 A/{  
9D51@b6k  
~lH2#u>g  
//等待子线程结束
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//int count = 0; 0
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//是否结束while循环 t&rr;W]  
boolean breakWhile = false; i&JI"Dd7  
k]yv#Pa  
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while(!bStop) wyv%c/WlS  
{ ]}nX$xy  
write_nPos(); /UiB1-*b  
Utility.sleep(500); iI!g1  
breakWhile = true; YG>6;g)Zm  
Xh`Oin}<  
:A`jRe.  
for(int i=0;i<nStartPos.length;i++) 6('xIE(R  
{ l7uEUMV  
if(!fileSplitterFetch.bDownOver) ;`FR1KIg  
{ n$3w=9EX*  
breakWhile = false; 8PvO_Gz5  
break; B[[1=  
} !tuK.?q|l  
} ~{!,ZnO*  
if(breakWhile) j4Y] 8  
break; zWf(zxGAz  
9v76A~~  
-A1:S'aN-  
//count++; o.>Yj)U  
//if(count>4) lsB.>NlU  
// siteStop(); PF:E{_~  
} *|)O  
'd9cCQ}  
FO?I}G22  
System.err.println("文件下载结束！"); <u2iXH5w  
} ph@2[rUp  
catch(Exception e){e.printStackTrace ();} 5z9'~Gfb  
} F1&7m )f$l  
#L xfE<^  
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//获得文件长度 a`S3v  
public long getFileSize() _Uup*#m  
{ YPS,[F'B.  
int nFileLength = -1; 8YkCTJfBGu  
try{ 7kQ,D,c'  
URL url = new URL(siteInfoBean.getSSiteURL()); -|_io,eL;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Fo&ecWhw  
httpConnection.setRequestProperty("User-Agent","NetFox"); gBE1aw;  
<&=3g/Y  
J*]JH{  
int responseCode=httpConnection.getResponseCode(); E1Rz<&L  
if(responseCode>=400) ;V)94YT  
{ .;NoKO7)  
processErrorCode(responseCode); ??XtN.]7  
return -2; //-2 represent access is error wm/>_  
} X$ 76#x  
)LE#SGJP  
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String sHeader; [`=:uUf3  
2%t!3F:  

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for(int i=1;;i++) fFd"21>  
{ a|@1RH>7H  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LrnE6U9  
//Utility.log(in.readLine()); 8!Q0:4Vb  
sHeader=httpConnection.getHeaderFieldKey(i); Dlo4Wy  
if(sHeader!=null) ?+y# t?
 
{ pt8#cU
\  
if(sHeader.equals("Content-Length")) q'<K$4_,%  
{ gPr&9pHU  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *wK7qS~VB2  
break; o1@. <Q+}  
} b;t b&o  
} q|.K&@_'K  
else *Y- rEF>  
break; gBXJ/BW$y  
} BZ@v8y _TA  
} Wx-rW  
catch(IOException e){e.printStackTrace ();} Fj0h-7L  
catch(Exception e){e.printStackTrace ();} }}~ t!/x  
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btIh%OM  
Utility.log(nFileLength); C'CdVDmX  
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return nFileLength; "AMsBvzgo  
} bL18G(5  
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R3} Z"  
//保存下载信息（文件指针位置） Qv:J#uVw?O  
private void write_nPos() m4kUA"n5  
{ K6z-brvw"  
try{ VWcR@/3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 9A1w5|X  
output.writeInt(nStartPos.length); O,!4 W\s  
for(int i=0;i<nStartPos.length;i++) )ia$pes  
{ d
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// output.writeLong(nPos); 8sxH
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output.writeLong(fileSplitterFetch.nStartPos); fIcra  
output.writeLong(fileSplitterFetch.nEndPos); XP_V  
} n{r
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output.close(); pM7xnL4  
} jRzQ`*KC#  
catch(IOException e){e.printStackTrace ();} B=J/HiwV)  
catch(Exception e){e.printStackTrace ();} D1<$]r,  
} t"Djh^=y  
Vch!&8xii  
k84JDPu#  
//读取保存的下载信息（文件指针位置） -YP>mwSN?  
private void read_nPos() ~`x<;Ts  
{ t=oTU,<  
try{  <IL$8a  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 
)9JuQ_R  
int nCount = input.readInt(); +{S^A)  
nStartPos = new long[nCount]; sy.U]QG  
nEndPos = new long[nCount]; NX4}o&mDwn  
for(int i=0;i<nStartPos.length;i++) ~",,&>#[K  
{ )t$|'c}  
nStartPos = input.readLong(); .]W A/}  
nEndPos = input.readLong(); Uw5`zl  
} ^YG.eT6iG  
input.close(); 1]j_4M14aA  
} &`4v,l^Zi6  
catch(IOException e){e.printStackTrace ();} a uz2n  
catch(Exception e){e.printStackTrace ();} 1u0NG)*f  
} j(maj  
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private void processErrorCode(int nErrorCode) -KG3_kE  
{ $di8#O*  
System.err.println("Error Code : " + nErrorCode); S\O6B1<:  
} y*5bF0  
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//停止文件下载 u2xb^vu  
public void siteStop() L E>A|M$X  
{ ~ -hH#5  
bStop = true; @}cZxFQ!C  
for(int i=0;i<nStartPos.length;i++) `Dco!ih  
fileSplitterFetch.splitterStop(); kf<5`8  
*FT )`  
bqDHLoB\1  
} Hc{0O7  
} qSWnv`hL  
//负责部分文件的抓取 ) Pdl[+a  
**FileSplitterFetch.java X%b.]A  
*/ va/$dD9  
package NetFox; R_2JP C  
uR7\uvibUO  
:9`T.V<?  
import java.io.*; *!*J5/b  
import java.net.*; :3x|U,wC  
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^L1#  
public class FileSplitterFetch extends Thread { C,xM)V^a  
0UB,EI8  
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String sURL; //File URL EO5k?k[*  
long nStartPos; //File Snippet Start Position d?/?VooU  
long nEndPos; //File Snippet End Position !~&vcz0>)9  
int nThreadID; //Thread's ID R2af>R  
boolean bDownOver = false; //Downing is over OxraaN`  
boolean bStop = false; //Stop identical Bld$<uU  
FileAccessI fileAccessI = null; //File Access interface *XK9-%3  
MMfcY 3#%  
oZV=vg5Dq  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =wW3Tr7~  
{ ![BQ;X  
this.sURL = sURL; .hxcx>%  
this.nStartPos = nStart; |E)Es!dr  
this.nEndPos = nEnd; 'MHbXFM  
nThreadID = id; ''f07R  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 L@|W&N;%a  
} XKU+'Tz  
qi\!<clv  
Sh=Px9'i  
public void run()
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{ ,rp-`E5ap  
while(nStartPos < nEndPos && !bStop) ,HxsU,xiG  
{ [~ sXjaL8  
*8uSy/l  
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try{ pCQB<6&1N  
URL url = new URL(sURL); =x4:jas  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _Z|s!~wdz  
httpConnection.setRequestProperty("User-Agent","NetFox"); PL#
8~e;'  
String sProperty = "bytes="+nStartPos+"-"; \1[I(u  
httpConnection.setRequestProperty("RANGE",sProperty); Xp=Y<`dX  
Utility.log(sProperty); :A,V<Es}I"  
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InputStream input = httpConnection.getInputStream(); IwIk;pB O  
//logResponseHead(httpConnection); -BNlZgk-^  
QJ`#&QRp  
\:8eN}B  
byte[] b = new byte[1024]; 9K@>{69WQ  
int nRead; FBM 73D@`  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) d]OoJK9&&  
{ bc"E=z  
nStartPos += fileAccessI.write(b,0,nRead); }TZ5/zn.Dw  
//if(nThreadID == 1) _,i]ra{%  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o
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} FKd5]am  
L)'JkX J  
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Utility.log("Thread " + nThreadID + " is over!"); %:n1S]Vr  
bDownOver = true; .F0V  
//nPos = fileAccessI.write (b,0,nRead); _XtLO-D  
} _=1SR\  
catch(Exception e){e.printStackTrace ();} uD&!]E3  
} \fphM6([RK  
} \#[W8k<Z  
J<Wz3}w6  
aXyu%<@k  
//打印回应的头信息 EOrWax@k$}  
public void logResponseHead(HttpURLConnection con) *hAeA+:  
{ GqI^$5?  
for(int i=1;;i++) 2hV#3i  
{ {4 !%'~  
String header=con.getHeaderFieldKey(i); FDaHsiI:  
if(header!=null) JEX
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); JbG\Ywi0]  
Utility.log(header+" : "+con.getHeaderField(header)); XnQd(B`M  
else 2B_6un];W  
break; h'<}
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} F_!6C-z  
} n37C"qJ/i  
]<q{0.  
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public void splitterStop() ?#xNz=V  
{ cI4%zeR  
bStop = true; _=jc%@]1y  
} WIXzxI<)  
y6'Fi(2yw  
H*3f8A&@s  
} ,~FyC_%*  
5+GW%U/  
h)q:nlKUW  
/* PG9won5_  
**FileAccess.java v@;:aN  
*//文件访问(定位，写) j-ugsV`2=*  
package NetFox; tnbaU%;|J  
import java.io.*; L1`^~m|  
iYA06~d  
!o*BRR*  
public class FileAccessI implements Serializable{ 9Ps:]Kp!vN  
]DdD FLM  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4x=rew>Ew  
RandomAccessFile oSavedFile;
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long nPos; Hjli)*ev  
M|FwYF^  
+&tY&dQQB  
public FileAccessI() throws IOException *9%<}z  
{ VG+Yhm<SL  
this("",0); B8 -/C\  
} 3=)/-l  
z-uJ+SA  
zzuDI_,/  
public FileAccessI(String sName,long nPos) throws IOException B4R!V!Z*  
{ *#Hi W)  
oSavedFile = new RandomAccessFile(sName,"rw"); ]c+qD,wqt>  
this.nPos = nPos; <"/Y`/
 
oSavedFile.seek(nPos); E8=.TM]L  
} "j3Yu4_ks  
|Wj)kr !|  
F {]:  
public synchronized int write(byte[] b,int nStart,int nLen) @y->4`N  
{ *(L4
rK\2  
int n = -1; 9x&,`95O  
try{ z7MJxjH  
oSavedFile.write(b,nStart,nLen); 4r-jpVN~  
n = nLen; y<k-d
br  
} nTY`1w.;  
catch(IOException e) @.T'  
{ J$&!Y[0  
e.printStackTrace (); E3.=|]W'  
} JJ,Fh .  
0F`@/C1y55  
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return n; XcaY'k#  
} ?AyG!F  
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} P$.Azrl  
/J3e[?78u  
X.,SXNS+B  
/* (SoV2[|  
**SiteInfoBean.java ;7 i0ko9  
*/ G?e,Q$  
package NetFox; q+dY&4&u  
H]"Z_n_  
CBs0>M/  
public class SiteInfoBean { }k duN0  
C>N)~Ut  
1]fqt[*)  
private String sSiteURL; //Site's URL DkA cT[  
private String sFilePath; //Saved File's Path Q0,]Q ]_  
private String sFileName; //Saved File's Name -a]oN:ERb  
private int nSplitter; //Count of Splited Downloading File 3w ?)H  
c>!>D7:7  
>t'/(y  
public SiteInfoBean() ]0xbvJ8oK  
{//nSplitter的缺省值为5 [xk1}D  
//default value of nSplitter is 5 @8|-
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this("","","",5); ]XJpy-U  
} jr*A1y*  
'%V ;oJ"  
;QW6Tgt11  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) v(FO8*5DZ  
{ Dq*>+1eW2  
sSiteURL= sURL; nmc=RK^cM  
sFilePath = sPath; :De}5BMy  
sFileName = sName; Z5[ t/  
this.nSplitter = nSpiltter; hBz~FB];&  
)1lR;fD  
c3P
 
} -#Yg B5  
9O?.0L  
/^DDU!=(<  
public String getSSiteURL() {]]nQ  
{ d vkA-9  
return sSiteURL; QT9(s\u  
} WHvN6  
]$4k+)6  
%K;,qS'N_  
public void setSSiteURL(String value) 3kdTteyy+  
{
@&S4j]rq  
sSiteURL = value; r=s,Ath  
} oA"t`,3  
!?Z}b.%W  
,78QLh9:  
public String getSFilePath() my[)/'  
{ !0fpD'f!n  
return sFilePath; cA`R~o"  
} R5r )01  
TWQf2  
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public void setSFilePath(String value) x7t<F4  
{ un6grvxr  
sFilePath = value;
{LbcG^k  
} g>_6O[;t%  
(pH13qU5  
>72j,0=e  
public String getSFileName() aa.EtKl  
{ S$%T0~PR~  
return sFileName; #v=hiL  
} ]"q)X{G(+  
Q68&CO(rE  
P_
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public void setSFileName(String value) zW!3>(L/  
{ 3 {\b/NL$  
sFileName = value; z62
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} 'vhgR2/  
Ua,Lg.z  
k5$_Q#  
public int getNSplitter() J1 a/U@"  
{ lHV bn7  
return nSplitter; <o3e0JCq  
} x5WFPY$wM  
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GW ?.b_6*  
public void setNSplitter(int nCount) *["9;_KD  
{ YnNB#x8|  
nSplitter = nCount; {e<J}-/?  
} & *B@qQ  
} AGx]sr
l  
a"b9h{h@  
ot;j6eAH~E  
/* XGFU *g`kq  
**Utility.java c`#E#  
*/ ]V6<h Psi  
package NetFox; Ib*l{cxN  
s!9.o_k  
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public class Utility { w[uK3Av  
YS{])+s  
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public Utility() NC>rZS]  
{ X<x"\Yk  
@r%[e1.  
.YYiUA-i9n  
} PM=
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,LSF@1|Fx  
//线程睡眠 Agl5[{]E  
public static void sleep(int nSecond) (W
VN*OR?  
{ gLsl/G  
try{ zg.'  
Thread.sleep(nSecond); Kg VLXI6  
} oA(jtX[(  
catch(Exception e) ^e"BY(  
{ IU{~{(
p"  
e.printStackTrace (); T@U_;v|rf  
} _.' j'j%  
} HN7(-ml=B  
6m_Y%&   
//日志 ^W eE%"  
public static void log(String sMsg) eZ[CqUJ&  
{ ^cZF#%k  
System.err.println(sMsg); U)=StpTT  
} B0?E$8a  
|+~CdA  
Pg{Dy>&2`I  
public static void log(int sMsg) !l?Go<^*L  
{ Op" \i   
System.err.println(sMsg); 54_CewL1P]  
} =W.b7 6_  
} SuB;Nb7r`  
c_~)#F%P  
[uT&sZxmg  
/* TbXp%O:[W  
**TestMethod.java $z1u>{  
*/ 7m~+
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package NetFox; Uq<c+4)5  
}y(1mzb  
~k/'_1)c  
public class TestMethod { cWl  
B# |w}hj  
$ii/Q:w T"  
public TestMethod() gGxgU$`#c  
{ ///xx/weblogic60b2_win.exe i;s&;_0{  
try{ `J|bGf#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); |#D3~au   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >2x[ub%$L  
SiteFileFetch fileFetch = new SiteFileFetch(bean); KqG:o+V=  
fileFetch.start(); J/>Y mi,  
} jmxjiJKP  
catch(Exception e){e.printStackTrace ();} btkD<1{g  
#~^#%G
 
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} -8-  
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public static void main(String[] args) Jt\?
,~,
  
{ &p8b4y_  
new TestMethod(); -M2c8P:.b  
} <.HX_z3l  
} %"r3{Hs  
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