http断点续传简单实现（java)

/* L|]w3}ZT@  
**SiteFileFetch.java >gX0Ij#G  
*/ LyJTK1]#  
package NetFox; M`9orq<  
import java.io.*; %!ER@&1f&  
import java.net.*; Q.pEUDq/  
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public class SiteFileFetch extends Thread { t_dw}I  
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#q~3c;ec  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1c<CEq:?e%  
long[] nStartPos; //开始位置 p0[,$$pM  
long[] nEndPos; //结束位置 6mI_Q2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .WL\:{G8;  
long nFileLength; //文件长度 e_>rJWI}  
boolean bFirst = true; //是否第一次取文件 .q_uJ_qu-  
boolean bStop = false; //停止标志 S1H47<)UF  
File tmpFile; //文件下载的临时信息 s{"`=dKT  
DataOutputStream output; //输出到文件的输出流 h0QYoDvbC  
L6[rvM|9_  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） D_yY0rRM  
public SiteFileFetch(SiteInfoBean bean) throws IOException e~t}z_>F  
{ &m%Pr  
siteInfoBean = bean; 7/^TwNsv  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @Q$/eL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7'{Yz  
if(tmpFile.exists ()) Ew?/@KAV\  
{ =XacG}_  
bFirst = false; P[#WHbn  
read_nPos(); Zeme`/aBb  
} skR,M=F~  
else Lilk8|?#W  
{ &-8-xw#.  
nStartPos = new long[bean.getNSplitter()]; uwH
)/BW)[  
nEndPos = new long[bean.getNSplitter()]; r_g\_y7ua  
} 7uv/@(J"$  
SVg@xu+  
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} Hz3 S^o7  
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public void run() G"U>fwFuK  
{ U3_yEvZ  
//获得文件长度 a_pCjG89  
//分割文件 +4:+qGAJ{  
//实例FileSplitterFetch Z|Lh^G  
//启动FileSplitterFetch线程 hBfzU\*0H  
//等待子线程返回 H%NLL4&wu  
try{ G7_"^r%c9;  
if(bFirst) :`>+f.)  
{ MR)KLM0  
nFileLength = getFileSize(); )Py+jc.  
if(nFileLength == -1) }*}`)rj,  
{
:WfB!4%!  
System.err.println("File Length is not known!"); u'~b<@wHB  
} l6`d48U
 
else if(nFileLength == -2) y`B!6p 5j  
{ YAC zznN  
System.err.println("File is not access!"); >nIcFm  
} !{]v='   
else h[`Op#^x3  
{ yz2oS|0'  
for(int i=0;i<nStartPos.length;i++) 7].IT(  
{ H`6Jq?\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); AXU!-er$  
} Zs$RKJ7  
for(int i=0;i<nEndPos.length-1;i++) j=jrzG+`  
{ GaK_9Eg-2  
nEndPos = nStartPos[i+1]; #`#aSqGmc  
} }PIGj}F/  
nEndPos[nEndPos.length-1] = nFileLength; qiKtR  
} )V$!  
} #PLB$
$  
,md7.z]U~  
kJ<Xq   
//启动子线程 .vOpU4  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; HH~  du  
for(int i=0;i<nStartPos.length;i++) Uo[5V|>X6  
{ L^al1T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @8M2'R\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), UVBw;V  
nStartPos,nEndPos,i); p|9ECdU>;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *6x^w%=A  
fileSplitterFetch.start(); b5 C}K  
} >yT@?!/Q>'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yE|}
 r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <,cIc]eX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", m2< *  
nEndPos = " + nFileLength); WWs[]zr  
// fileSplitterFetch[nPos.length-1].start(); h,6S$,UI  
!e\R;bYM  
ZRq}g:  
//等待子线程结束 / -qt}  
//int count = 0; UE`4$^qs  
//是否结束while循环 #z^1)7  
boolean breakWhile = false; b;;Kxi:7$}  
;YXr
G  
-MW(={#  
while(!bStop) =jv$ 1  
{ yb.|7U?/x  
write_nPos(); iN/!k.ybW}  
Utility.sleep(500); *Qwhi&k  
breakWhile = true;
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:2Rci`lp  
NG W{Z~l  
for(int i=0;i<nStartPos.length;i++) V45Udwp^  
{ E?h2e~ ,]  
if(!fileSplitterFetch.bDownOver) Cv(N5mA2  
{ TNT"2FoBd  
breakWhile = false; H6\ x.J^,  
break; -5_xI)i
 
} {2*l :'  
} 1;~1U9V  
if(breakWhile) 6V6g{6W,/  
break; k|c0tvp  
Q;,3W+(  
yr 9)ga%  
//count++; Wu;|(2I  
//if(count>4) QZa#iL  
// siteStop(); ~+iJp
W  
} Q
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'CAukk|  
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System.err.println("文件下载结束！"); DCzPm/#b  
} '2J6%Gg  
catch(Exception e){e.printStackTrace ();} +rpd0s
49  
} _@;3$eB  
8=o5;]Cg  
?CZD^>6  
//获得文件长度 BW-P%:B1!R  
public long getFileSize() H;Qn?^  
{ WHLK
f  
int nFileLength = -1; vA-p}]%  
try{ p#BvlS=D  
URL url = new URL(siteInfoBean.getSSiteURL()); s /q5o@b{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +9F#~{v`4a  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0HuRFl  
Vg~ kpgB
 

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int responseCode=httpConnection.getResponseCode(); s1$#G!'  
if(responseCode>=400) =i>F^7)U1  
{ 2
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processErrorCode(responseCode); F1*rUsRKN  
return -2; //-2 represent access is error {u6fa>R&$  
} ,(W98}nB  
I>o; %}  
NWN)b&}  
String sHeader; XJ/kB8  
_rVX_   

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for(int i=1;;i++) w}
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{ oYErG],  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }lpm Hvs  
//Utility.log(in.readLine()); Rj;e82%%N
 
sHeader=httpConnection.getHeaderFieldKey(i); I/V#[KC  
if(sHeader!=null) TaJn2cC^  
{ cP=mJ1  
if(sHeader.equals("Content-Length")) $uB(@Ft.  
{ /G+gk0FW  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4EbiCSo
 
break; JP*mQzZL  
} c7!`d.{90  
} dk`!UtNNRa  
else  8\ ;G+  
break; pv SFp-:_  
} o xu9
v/  
} JlGD.!`  
catch(IOException e){e.printStackTrace ();} 3DvkoV  
catch(Exception e){e.printStackTrace ();} !sQ8,l0h  
bXLa~r4\  
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Utility.log(nFileLength); &YKzK)@  
;FflEL<7Y  
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return nFileLength; yS3s5C{C  
} 7Q}@L1A9F,  
M=_CqK*  
"0)
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//保存下载信息（文件指针位置） G_4P)G3H  
private void write_nPos() Nj8)HR  
{ |T&#"q,i9%  
try{ ^BTNx2VHf  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S`@*zQ  
output.writeInt(nStartPos.length); @Qozud\?  
for(int i=0;i<nStartPos.length;i++) aZ,Wa-k  
{ #eyx  
// output.writeLong(nPos); Z@A1+kUS  
output.writeLong(fileSplitterFetch.nStartPos); M'7x:Uw;  
output.writeLong(fileSplitterFetch.nEndPos); H9!*DA<W  
} jzMGRN/67  
output.close(); kO4~N-&  
} k]5L\]>y  
catch(IOException e){e.printStackTrace ();} @$G K<jl  
catch(Exception e){e.printStackTrace ();} H`@7o8oj1  
} )\G#[Pc7  
KrH;o)|  
3$;v# P$%N  
//读取保存的下载信息（文件指针位置） vdzC2T  
private void read_nPos() f`J"A:  
{ kICYPy  
try{ 8;3
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); I =pdjD  
int nCount = input.readInt(); 1sA-BQL  
nStartPos = new long[nCount]; uGWk(qn  
nEndPos = new long[nCount];  ond/e&1  
for(int i=0;i<nStartPos.length;i++) -E"o)1Pj6C  
{ 5]+eLKXB  
nStartPos = input.readLong(); ?GZs5CnS  
nEndPos = input.readLong(); v}@6"\  
} W>Kn*Dy8~  
input.close(); o\[nGf C&  
} "H@AT$Ny(  
catch(IOException e){e.printStackTrace ();} n1h+`nsf  
catch(Exception e){e.printStackTrace ();} ly+7klQ;.  
} C?k4<B7V  
6m&I_icM  
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private void processErrorCode(int nErrorCode) 8nM]G4H.f  
{ m`aUz}Y>c  
System.err.println("Error Code : " + nErrorCode); q9^r2OO  
} F{Hy@7  
%## bg<  
2e&Zs%u  
//停止文件下载 d"a`?+(Q  
public void siteStop() V,}cDT>  
{ $2 0*&4y^  
bStop = true; a*`J]{3G  
for(int i=0;i<nStartPos.length;i++) :T2K\@  
fileSplitterFetch.splitterStop(); FMiY
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'|.u*M,b  
} ~ nIZg5  
} j4
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//负责部分文件的抓取 Gf>T{Q`,is  
**FileSplitterFetch.java =n!8>8d  
*/ )`a R?_  
package NetFox; HU'}c*d]
 
Z1zC@z4sUj  
h fNBWN  
import java.io.*; BDA\9m^3  
import java.net.*; F6Ixu_s  
va)\uXW.N  
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public class FileSplitterFetch extends Thread { SU^/qF%8  
4CqZvdC  
aOOY_S E  
String sURL; //File URL ^H>vJT  
long nStartPos; //File Snippet Start Position . 2WZb_B  
long nEndPos; //File Snippet End Position /D~:Ufw  
int nThreadID; //Thread's ID RV~w+%f  
boolean bDownOver = false; //Downing is over U i;o/Z3  
boolean bStop = false; //Stop identical %u#pl=k}  
FileAccessI fileAccessI = null; //File Access interface }  ?  
2w%1\TcB$  
na~ r}77o  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException nt7ui*k  
{ ^#%[  
this.sURL = sURL; 8d]= +n!  
this.nStartPos = nStart; X~x]VKr/  
this.nEndPos = nEnd;
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|  
nThreadID = id; phTZUmi  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +`ZcYLg)#  
} nBQG.3  
5D'8 l@7  
s)>]'ii  
public void run() ?/O+5rjA  
{ 1}N5WBp  
while(nStartPos < nEndPos && !bStop) ?x:\RNB/  
{ xv /w %  
0tA+11Iu  
dJ$}]   
try{ #fwG~Q(  
URL url = new URL(sURL);
&iuc4"'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _3`{wzMA  
httpConnection.setRequestProperty("User-Agent","NetFox"); U7Ps2~x3  
String sProperty = "bytes="+nStartPos+"-"; ]+oPwp;il  
httpConnection.setRequestProperty("RANGE",sProperty); +* &!u=%G  
Utility.log(sProperty); 9nB:=`T9  
z\v\T|C  
%H:!/'45  
InputStream input = httpConnection.getInputStream(); QjPcfR\  
//logResponseHead(httpConnection); P /Js!e<\  
@o8\
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H4)){\  
byte[] b = new byte[1024]; K'y;j~`-  
int nRead; pbu8Ib8z  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Iu%S><'+  
{ Rj-<tR{  
nStartPos += fileAccessI.write(b,0,nRead); Zl]\sJ1"  
//if(nThreadID == 1)  IF uz'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ms<?BgCSz  
} D=e&"V a  
5pz%DhjLo  
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Utility.log("Thread " + nThreadID + " is over!"); \4mw>8wA  
bDownOver = true; 0,,x|g$TpT  
//nPos = fileAccessI.write (b,0,nRead); C^.:{  
} UnGG%  
catch(Exception e){e.printStackTrace ();} $/6.4"j  
} Ig]Gg/1G  
} ,xNuc$8Jd  
J-hP4t&x  
HA>b'lqBM  
//打印回应的头信息 {3'z}q  
public void logResponseHead(HttpURLConnection con) *l^h;RSx  
{ Lylw('zZ  
for(int i=1;;i++) uEH&]M>d_  
{ JZ'`.yK:  
String header=con.getHeaderFieldKey(i); Td}#o!4!  
if(header!=null) In5'(UHW:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /wVrr%SN  
Utility.log(header+" : "+con.getHeaderField(header)); J)6f"{} &  
else "^yTH/m  
break; IA!( 'K
s  
} k~h'`(  
} r1
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public void splitterStop() Jn-iIl  
{ D^$Nn*i;U  
bStop = true; Y&'Bl$`  
} Ns?y) G>:  
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}hv>LL  
} PSNfh7g  
?>LsIPa  
g`k_o<'JC  
/* +eg$Z]Lht  
**FileAccess.java _0<qS{RW  
*//文件访问(定位，写) FE,&_J"  
package NetFox; I6ffp!^}Y  
import java.io.*; TU&gj1  
Ol"*(ea-TX  
bzz=8n  
public class FileAccessI implements Serializable{ t 5g@t0$  
-L}crQl.'c  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 l1fP@|  
RandomAccessFile oSavedFile; :''^a  
long nPos; Zu951+&`  
RBd{1on  
sluR@[l  
public FileAccessI() throws IOException ,Y6Me+5B  
{
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this("",0); TL lR"L5  
} D7T(B=S6  
(sSMH6iCif  
sS7r)HV&GI  
public FileAccessI(String sName,long nPos) throws IOException Q&S\?cKe  
{ x>THyY[sq  
oSavedFile = new RandomAccessFile(sName,"rw"); `VM@-;@w  
this.nPos = nPos; BuII|j  
oSavedFile.seek(nPos); Z<
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}
;& ny< gQ  
@=B'<&g$Xv  
H
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public synchronized int write(byte[] b,int nStart,int nLen) P]hS0,sE<(  
{ Q{F*
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int n = -1;  *(5y;1KU  
try{ 8DHohhN  
oSavedFile.write(b,nStart,nLen); `&xo;Vnc  
n = nLen; OLp;eb1g  
} 2YI#J.6]H  
catch(IOException e) 0 UdAF  
{ \}[{q  
e.printStackTrace (); 7)aitDD  
} /<,LM8n  
x@/ N9*  
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return n; ,5J-
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} y8=p;7DY  
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} /
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/* F/GfEMSE  
**SiteInfoBean.java #'m&<g,  
*/ X-,scm  
package NetFox; aD)XxXwozm  
L7oLV?k  
1|/P[!u  
public class SiteInfoBean { U,Py+c6  
"BSSA%u?c  
w;@DcX$]  
private String sSiteURL; //Site's URL ZuF"GNUC  
private String sFilePath; //Saved File's Path ]XX9.Xh=-  
private String sFileName; //Saved File's Name !}%,rtI  
private int nSplitter; //Count of Splited Downloading File v[4A_WjT  
*j9{+yO{ZE  
6b&<5,=d:  
public SiteInfoBean() /HCd52  
{//nSplitter的缺省值为5 a|aRUxa0"  
//default value of nSplitter is 5 ?S&pq?   
this("","","",5); f44b=,Lry5  
} 5m2`$y-nb  
{c5%.<O  
$v|/*1S  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) I{>U7i 5  
{ zdY+?s)p  
sSiteURL= sURL; 9e^H
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sFilePath = sPath; `U:W(\L  
sFileName = sName; ch2Qk8  
this.nSplitter = nSpiltter; 9nW/pv  
S<), ,(  
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} 7kDX_,i  
+%yVW f  
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public String getSSiteURL() H"v3?g`S%  
{ /JaCbT?*T  
return sSiteURL; )C>4?)  
} }~gBnq_DDU  
wk @-O}W  
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public void setSSiteURL(String value) a`SQcNBf*  
{ V?KACYd@O  
sSiteURL = value; h4@v.GI  
} N^,@s"g  
pUs:r0B  
{P'TtlEp  
public String getSFilePath() H
8^U!"~E  
{ v9Kx`{1L  
return sFilePath; CH |A^!Zm  
} ?~G D^F  
i={ :6K?^  
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public void setSFilePath(String value) ce/Z[B+d  
{ 8<cD+Jtj  
sFilePath = value; I%dFVt@  
} FmU>q)  
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}1EfyR  
public String getSFileName() P(z#Wk  
{ Z#8O)GK  
return sFileName; gO C5  
} [8Zq 1tU;G  
+APf[ZpU  
ppv/A4Kv  
public void setSFileName(String value) 7
"L`|O?8)  
{ NzRpI5\.  
sFileName = value; F"7dN*7  
} XS!mtd<q  
jI`1>>N&1  
-#yLH  
public int getNSplitter() W'2a1E  
{ etY/K0  
return nSplitter; \k6Ho?PL  
} 4AI\'M"d  
=F>@z4[P-  
7C7eXJ9q  
public void setNSplitter(int nCount) ?sb Ob  
{ fX)C8J^=G  
nSplitter = nCount; b>R/=tx  
} }Qj
p,(ye  
} FB<#N+L\  
b_Us%{  
oH/6  
/* a<CN2e_Z  
**Utility.java mp2J|!Lx  
*/ ]ZkhQ%  
package NetFox; UL0%oJ#  
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public class Utility { 11Kbj`sRZ  
!f~ =p
 
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public Utility() y(M
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{ $Iuf(J-5[  
& i,on6  
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} (<?6X9F:N  
QN=a{  
//线程睡眠 `I$'Lp#5  
public static void sleep(int nSecond) }kg?A o
o  
{ cP[3p:  
try{ z@E-pYV  
Thread.sleep(nSecond); !;'.mMO&%  
} ,fS}cpV  
catch(Exception e) }]w/`TF  
{ [zp v3Uw  
e.printStackTrace (); 
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} !,}W|(P)  
} -uZ bVd  
l?CUd7P(a  
//日志 Tjo K]
]  
public static void log(String sMsg) G#.(%,  
{ =j[zMO  
System.err.println(sMsg); C2GF N1i  
} rM6^pzxe  
b-e3i;T!}~  
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public static void log(int sMsg) Skgvnmk[U  
{ 9g3J{pKcZ  
System.err.println(sMsg); 2.)@u~^Q  
} ^p#f B4z  
} 'LZF^m _<<  
uSSnr#i^j  

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/* d#:&Uw  
**TestMethod.java 6x KbK1W  
*/ 0raVC=[  
package NetFox; SX)giQLU  
l,Un7]*  
XWvT(+J  
public class TestMethod { KE\p|Xi  
MCH
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2 g"_
*[  
public TestMethod() 4HlOv%8  
{ ///xx/weblogic60b2_win.exe P<b.;Oz__-  
try{ Dt,b\6  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1Sox@Ko  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); BcaMeb-Z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); t1p}
  
fileFetch.start(); )&di c6r  
} Xv3u}nPMq  
catch(Exception e){e.printStackTrace ();} !xoN%5!  
.$b]rx7$~  
$Z)Dvy|  
} dsP|j(y  
_+0l+a*D  
REnd# V2x  
public static void main(String[] args) Z;shFMu  
{ iorKS+w"  
new TestMethod(); f!;i$Oif  
} >E^?<}E~.  
} 0S@O]k)  
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