http断点续传简单实现（java)

/* &#;UKk~)Of  
**SiteFileFetch.java in#g  
*/ f4`=yj*  
package NetFox; uN6TV*]:  
import java.io.*; Wl::tgU  
import java.net.*; tR0o6s@v/<  
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public class SiteFileFetch extends Thread { t[iE >  
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9<\wa/#  
SiteInfoBean siteInfoBean = null; //文件信息Bean >KM<P[BRd  
long[] nStartPos; //开始位置 In^$+l%O[  
long[] nEndPos; //结束位置 N55;oj_K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ngh9+b6[  
long nFileLength; //文件长度 Q@/wn  
boolean bFirst = true; //是否第一次取文件 !cp ,OrO\  
boolean bStop = false; //停止标志 1 ,[T;pdDd  
File tmpFile; //文件下载的临时信息 ddlLS  
DataOutputStream output; //输出到文件的输出流 eNN%%Q  
,Iwri\  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Tv~<W4  
public SiteFileFetch(SiteInfoBean bean) throws IOException A[=)Zw "  
{ S37Bl5W  
siteInfoBean = bean; 65s|gfu/  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); e)7[weGN  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,C(")?4aJ  
if(tmpFile.exists ()) &``;1/J*W  
{ cKFzn+  
bFirst = false; ?sp  
read_nPos(); S-'iOJ1]  
} MCL5a@BX)  
else ykX}T6T  
{ ~A [ Ju%R  
nStartPos = new long[bean.getNSplitter()]; }UQBaqDH  
nEndPos = new long[bean.getNSplitter()]; [S-NGip  
} rv:,Os_  
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vL\wA_z"<H  
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} e!G I<  
r$R(4q:  
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public void run() j4+hWalm
 
{ mcp}F|ws  
//获得文件长度 aq,&W q@  
//分割文件 <iJ->$  
//实例FileSplitterFetch )#IiHBF  
//启动FileSplitterFetch线程 xREqcH,vU  
//等待子线程返回 @6}c\z@AxM  
try{ 0@^YxU[YN  
if(bFirst) kM]?  
{ &Q(Q/
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nFileLength = getFileSize(); 9'td}S  
if(nFileLength == -1) VU}UK$JN  
{ +Rxf~m(pV  
System.err.println("File Length is not known!"); x_bS-B)%Y:  
} D3(|bSca  
else if(nFileLength == -2) JU/K\S2%,  
{ |W`1#sP>  
System.err.println("File is not access!"); C&Ow*~  
} [1 w  
else YeYFPi#  
{ h*h+VM  
for(int i=0;i<nStartPos.length;i++) byyz\>yAVq  
{ FyQ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Pm7,Nq)<>n  
} mNWmp_c,1  
for(int i=0;i<nEndPos.length-1;i++) @H1pPr  
{ u <D&RT  
nEndPos = nStartPos[i+1]; WI](a8bm  
} qW$IpuK  
nEndPos[nEndPos.length-1] = nFileLength; Y'%sA~g  
} AX<TkS@wjb  
} E;| q  
kO~xE-(=  
n M,m#"AI  
//启动子线程 W446;)?5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @,pO%,E6  
for(int i=0;i<nStartPos.length;i++) l4|bpR Cp  
{ Uj1^?d+b  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), dB^J}_wp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W^60
BZ  
nStartPos,nEndPos,i); n"(n*Hf7b  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fPZBm&`C  
fileSplitterFetch.start(); qYGnebn@\  
} MU-ie*+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Xr6lYO_R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9 qqy(H  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", x44)o:  
nEndPos = " + nFileLength); xHZx5GJp9  
// fileSplitterFetch[nPos.length-1].start(); :-ax5,J>q  
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"Yq-s$
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//等待子线程结束 q~_Nv5r%O  
//int count = 0; ~}$:iyJV(>  
//是否结束while循环 J0C<Qb[  
boolean breakWhile = false; }\OLBg/  
+mMn1&  
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while(!bStop) ()}O|JL:K  
{ ;)u}`4~L  
write_nPos(); UVxE~801Y  
Utility.sleep(500); Ajs<a(,6  
breakWhile = true; -TjYQ  
8y/YX  
@@'zMV%  
for(int i=0;i<nStartPos.length;i++) wvp
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{ hc`9Y  
if(!fileSplitterFetch.bDownOver) C W7E2 ^P$  
{ WK:~2m&y  
breakWhile = false; 3@XCP-`  
break; 9kH~+  
} C>:F4"0  
} }8fxCW*|  
if(breakWhile) N@58R9P<p  
break; `IFt;Ja\6  
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//count++; %
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//if(count>4) E)09M%fe  
// siteStop(); cx1U6A+  
} mhnD1}9,Ih  
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o3
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System.err.println("文件下载结束！"); &&M-5XD  
} >O9j},X  
catch(Exception e){e.printStackTrace ();} kIiId8l  
} JUF[Y^C  
~ifq_Ag.  
/49PF:$?  
//获得文件长度 r*0a43mC1  
public long getFileSize() U@ALo  
{ `(_cR@\  
int nFileLength = -1; &:S_ewJK7  
try{ N+"Y@X yg  
URL url = new URL(siteInfoBean.getSSiteURL()); #CW]70H`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
eW1$;.^  
httpConnection.setRequestProperty("User-Agent","NetFox"); {5#P1jlT  
dY;^JPT  
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int responseCode=httpConnection.getResponseCode(); dV<M$+;s]  
if(responseCode>=400) InH
R>,  
{ cx_[Y  
processErrorCode(responseCode); =c(_$|0  
return -2; //-2 represent access is error 4CW/  
} U#Wc!QN-t  
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String sHeader; 5l=B,%s  
pyT+ba#  
Z,lUO.  
for(int i=1;;i++) ":Kn@S'{(  
{ }2:bYpYQ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /A9Mv%zjk  
//Utility.log(in.readLine()); m{JiF-=u  
sHeader=httpConnection.getHeaderFieldKey(i); rPaD#GA[7  
if(sHeader!=null) f`:e#x  
{ +LV'E#h!Q
 
if(sHeader.equals("Content-Length")) k]qZOO}  
{ ,au64sH  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &VY;Al  
break; =<
O{t#]  
} +y6|Nq  
} tmRD$O%:  
else cEsBKaN
 
break; 79s6U^vv"  
} (e=ksah3>  
} s|pb0  
catch(IOException e){e.printStackTrace ();} ~XsS00TL`G  
catch(Exception e){e.printStackTrace ();} ~BERs;4  
\xDu#/^  
[9BlP  
Utility.log(nFileLength); "2HRuqf  
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return nFileLength; $-=aqUU  
} HoH3.AY X  
)_GM&-  
]WWre},  
//保存下载信息（文件指针位置） !Ya 
+  
private void write_nPos() ~_8Ve\Y^/  
{ B 0 K2Uw  
try{ at,Xad\j  
output = new DataOutputStream(new FileOutputStream(tmpFile)); tPO.^  
output.writeInt(nStartPos.length); ?9H
7Twi+T  
for(int i=0;i<nStartPos.length;i++) **_VNDK+  
{ |GdA0y\v*}  
// output.writeLong(nPos); Co[[6pt~  
output.writeLong(fileSplitterFetch.nStartPos); u\t[rC=yd  
output.writeLong(fileSplitterFetch.nEndPos); s.=)p"pTd  
} l>~:lBO  
output.close(); X2M<DeF:  
} puZ<cV e/  
catch(IOException e){e.printStackTrace ();} iL|*g3`-f  
catch(Exception e){e.printStackTrace ();} l2VO=RDiW  
} ;cp-jY_U  
_q6+]  
ua|qL!L+  
//读取保存的下载信息（文件指针位置） h,FP,w;G  
private void read_nPos() +}mj6I  
{ K8|6r|x  
try{ g?`D8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); II>X6  
int nCount = input.readInt(); Y0s^9?*  
nStartPos = new long[nCount]; 1Y}gki^F  
nEndPos = new long[nCount]; "Y(S G  
for(int i=0;i<nStartPos.length;i++) R^1= :<)C  
{ OiM{@  
nStartPos = input.readLong(); &=$8 v"&^  
nEndPos = input.readLong(); ngeX+@  
} EF"ar  
input.close();
T?AGQcG  
} Y1`.  
catch(IOException e){e.printStackTrace ();} s$H5W`3  
catch(Exception e){e.printStackTrace ();} ;lYO)Z`3\  
} }s}9@kl;&  
&CUkR
6  
>x2T'  
private void processErrorCode(int nErrorCode) wf|CE410  
{ !cSD9q*  
System.err.println("Error Code : " + nErrorCode); Vg:P@6s  
} aj(M{gFq~  
)
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//停止文件下载 CvbY2_>Nh  
public void siteStop() ec=4L@V*  
{ HS(
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bStop = true; y{j>4g$:z  
for(int i=0;i<nStartPos.length;i++) t&eD;lg :  
fileSplitterFetch.splitterStop(); Q96g7[  
9sYX(Fl  
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} B2845~\.  
} |I OTW=>  
//负责部分文件的抓取 Rx`0VQ  
**FileSplitterFetch.java QO#ZQ~  
*/ l\$C)q6O  
package NetFox; QRdb~f;<hj  
n8:2Z>  
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import java.io.*; ]nfS vPb  
import java.net.*; N"E\o,_  
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public class FileSplitterFetch extends Thread { P]6pPS  
c$e~O-OVD?  
=WO{h48]  
String sURL; //File URL xHD!8B)  
long nStartPos; //File Snippet Start Position 
.zegG=q  
long nEndPos; //File Snippet End Position \2NiI]t]  
int nThreadID; //Thread's ID E"L'm0i[[  
boolean bDownOver = false; //Downing is over :-6_X<  
boolean bStop = false; //Stop identical @F3d9t-  
FileAccessI fileAccessI = null; //File Access interface .S?,%4v%%  
|?g2k:fzB7  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8\I(a]kM`  
{ 8i:b~y0  
this.sURL = sURL; 6PPvfD^  
this.nStartPos = nStart; \ g0  
this.nEndPos = nEnd; "4"L"lJ   
nThreadID = id; R0/~) P  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ZT^PL3j+  
} [Xz7.<0#U  
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public void run() n"dT^ g  
{ V).M\  
while(nStartPos < nEndPos && !bStop) .pdgRjlSn  
{ ?^"S%Vb  
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MaM
s(  
try{ C}00S{nAZ  
URL url = new URL(sURL); 7XwFO0==  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); UyF]gO  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]\_4r)cN<n  
String sProperty = "bytes="+nStartPos+"-"; F[?t"d  
httpConnection.setRequestProperty("RANGE",sProperty); 7 'f>  
Utility.log(sProperty); D2?7=5DgS  
Wg$MKc9Vy[  
|2
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InputStream input = httpConnection.getInputStream(); |J6CH87>  
//logResponseHead(httpConnection); PMTyiwlm  
"arbUX~d  
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byte[] b = new byte[1024]; xknP `T  
int nRead; =E,*8O]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) sX**'cH  
{ W5yqnjK $4  
nStartPos += fileAccessI.write(b,0,nRead); 
,YiBu^E9  
//if(nThreadID == 1) ;XTP^W!6f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Af -{'  
} ;e[-t/SI  
\,_%e[g49  
=)T5Y,+rJ  
Utility.log("Thread " + nThreadID + " is over!"); rsc8lSjH  
bDownOver = true; )?_c7 R  
//nPos = fileAccessI.write (b,0,nRead); W}Z|v M$  
} s+(8KYTs`  
catch(Exception e){e.printStackTrace ();} VTV-$Du[}  
} ^
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} (>Tu~Vo  
=UYc~VUYnT  
~5JXY5*o  
//打印回应的头信息 i4uUvZf  
public void logResponseHead(HttpURLConnection con) g!K(xhEO  
{ Y]Xal   
for(int i=1;;i++) )9PQj  
{ VvPTL8Z  
String header=con.getHeaderFieldKey(i); \.*aC)  
if(header!=null) 43(+3$VM7  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); N}^\$
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Utility.log(header+" : "+con.getHeaderField(header)); G,$jU9 f  
else 4K4?Q+?  
break; PVU(RJ
 
} Q*lZ;~R  
} bx5X8D  
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public void splitterStop() WO '33Q(  
{ ~s88JLw%&u  
bStop = true; H(""So7L  
} .=K@M"5&  
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/r]IY.  
} WAob"`8]  
Ao=.=0os  
!rwv~9I  
/* //AS44^IS  
**FileAccess.java #5'9T:8  
*//文件访问(定位，写)
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package NetFox; ya|7hz{  
import java.io.*; P
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{E!$<A9  
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public class FileAccessI implements Serializable{ j4Lf6aUOX  
y=q\1~]Z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /<M08ze  
RandomAccessFile oSavedFile; >0u4>=#  
long nPos; \5O4}sm$*  
zQD$+q5h  
 4INO .  
public FileAccessI() throws IOException #,$d!l @  
{ jtN2%w;  
this("",0); RELLQpz3  
} CxwZ$0  
+e4o~p  
S^
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public FileAccessI(String sName,long nPos) throws IOException bl:.D~@  
{ jYuH zf  
oSavedFile = new RandomAccessFile(sName,"rw");  &grT}  
this.nPos = nPos; H{9di\xnEm  
oSavedFile.seek(nPos); ^TnBtIU-B  
} friNo^v&  
q(_pk&/  
@@_f''f$  
public synchronized int write(byte[] b,int nStart,int nLen) @-)?2CH[8  
{ 6x6PP}IX  
int n = -1; @R>J\>  
try{ r1xNU0A  
oSavedFile.write(b,nStart,nLen); NtSa#$A  
n = nLen; .[NB"\<q  
} s9@/(_  
catch(IOException e) t|%wVj?_  
{ 9}jF]P*Q  
e.printStackTrace (); >2,x#RQs  
} +|KnO  
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return n; O| ) [j@7  
} VW$Hzx_z  
+r"{$'{^  
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} g,r'].Jg  
#jv~FR`4v^  

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/* f3[gAY  
**SiteInfoBean.java d.3-@^P  
*/ X@2[!%n
m  
package NetFox; :4;ZO~eq!  
F/IXqj  
B{PI&a9~s%  
public class SiteInfoBean { M6[&od  
&2d^=fih  
B#N(PvtE  
private String sSiteURL; //Site's URL D ]:sR  
private String sFilePath; //Saved File's Path R6r'[-B2  
private String sFileName; //Saved File's Name Cq(dj^/~m  
private int nSplitter; //Count of Splited Downloading File Xk8+m>   
d@<(Z7|  
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public SiteInfoBean() T;IaVMFG|d  
{//nSplitter的缺省值为5 x$tx!%,)/S  
//default value of nSplitter is 5 Lo5itW  
this("","","",5); !-_0I
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} ba^B$$?Bo  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?suNA  
{ g[!t@K  
sSiteURL= sURL; I6,'o)l{_  
sFilePath = sPath; l\I#^N  
sFileName = sName; `lX |yy"  
this.nSplitter = nSpiltter; /GD4GWv :  
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7  
=* oFs|v  
} xT6&;,|`  
wt0^R<28  
B"ZW.jMaI  
public String getSSiteURL() d[9c6C:<q  
{ i<@6f'Kir  
return sSiteURL; nlOM4fJ(  
} K[!OfP  
SV0E7qX  
71_{FL8  
public void setSSiteURL(String value) !o1{. V9q  
{ =UE/GTbl  
sSiteURL = value;  G?AZ%Yx  
} ze@NqCF  
(A|Gb2X  
@KfFtR-;  
public String getSFilePath() =ZR9zL=h  
{ ViIt'WX  
return sFilePath; $hZb<Xz  
} sEP-jEuwG  
fl#gWAM  
(Z;;v|F.i=  
public void setSFilePath(String value) <5X?6*Qvr  
{ r~&"D#)sy  
sFilePath = value; 2oyTS*2u_&  
} SR7$m<0t*  
bw\fKZ  
&MKG#Y}  
public String getSFileName() 3z';Zwz &X  
{ +LuGjDn0  
return sFileName; EhL 8rR  
} KJ M:-z@  
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WDQtj$e+  
public void setSFileName(String value) #RT}-H  
{ {|nm0vg`A  
sFileName = value; <+I^K 7   
} &/R`\(
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&D0suK#  
public int getNSplitter() x(pq!+~K  
{ |U)m'W-(q  
return nSplitter; G347&F)  
} d*Q:[RUf,  
itClCEOA  
~'>RK  
public void setNSplitter(int nCount) E^B*:w3  
{ H<T9$7Yr%r  
nSplitter = nCount; {C3AxK0  
} q/w<>u  
} k]?M^jrm  
)NAC9:8!  
GG%X1c8K  
/* {uH 4j4)2  
**Utility.java `2`Nu:r^  
*/ m}/LMY  
package NetFox; {,EOSt
a  
oE@{h$=  
tgoOzk^  
public class Utility { AE0d0Y~9  
'NCxVbyYD  
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public Utility() >`L)E,=/  
{ ."b=dkx  
$Lg%CY  
%{qJkjG  
} NJK?5{H'  
hpp>+=  
//线程睡眠 Xb +)@Y4h  
public static void sleep(int nSecond) b[p<kMTir  
{ ;ELQIHnD"  
try{ DwM4/m  
Thread.sleep(nSecond); (}E-+:vFU  
} uX_A4ht*  
catch(Exception e) . +_IpygQ  
{ GtI]6t  
e.printStackTrace (); \;AW/&Ea  
} ~um+r],@@  
} ;m6Mm`[i
<  
BkfWZ O{7  
//日志 \bAsn89O  
public static void log(String sMsg) E><!Owxt/  
{ F%QZe*m[  
System.err.println(sMsg); p_h)|*W{  
} +9Z RCmV  
R7aS{8nn  
"j|}-a  
public static void log(int sMsg) C
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{ _|%pe]St  
System.err.println(sMsg); X&qRanOP;z  
} JmN,:bI  
} DF D5">g@  
fq-$u;~h  
:()(P9?  
/* tMGkm8y-A  
**TestMethod.java <jdS0YT  
*/ mtDRF'>P:  
package NetFox; KI(9TI*  
xR+=F1y  
f:
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public class TestMethod { Ht^MY  
=w&%29BYq  
[{3WHS.  
public TestMethod() <()xO(  
{ ///xx/weblogic60b2_win.exe $s2
Ty1  
try{ etF?,^)h=g  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xTQV?g J  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); /Z<"6g?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Dz,Fu:)  
fileFetch.start(); BcV;EEi  
} Yh/-6wg  
catch(Exception e){e.printStackTrace ();} $$YLAgO4  
4/D~H+k  
v8g3]MVj3  
} QrDrdA  
_@D}2  
rXo2MX@u  
public static void main(String[] args) }%k,PYe/  
{ wP3PI.g-g  
new TestMethod(); @~6A9Fr  
} 5xW)nEV  
} N>i1TM2  
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