http断点续传简单实现（java)

/* Xji<oih  
**SiteFileFetch.java um,Zt  
*/ :Fu.S1j$  
package NetFox; 3l
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import java.io.*; !bRoNP  
import java.net.*; i#=s_v8  
d%8hWlffz  
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public class SiteFileFetch extends Thread { >Ta|#]{  
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SiteInfoBean siteInfoBean = null; //文件信息Bean dJ#mk5= "  
long[] nStartPos; //开始位置 ncjtv"2R  
long[] nEndPos; //结束位置 AQ7w5}g+V  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 t&*X~(Yb!  
long nFileLength; //文件长度 K`Vi5hR~c  
boolean bFirst = true; //是否第一次取文件 <#k(g\/R  
boolean bStop = false; //停止标志 h0_od/D1r  
File tmpFile; //文件下载的临时信息 N D`?T &PK  
DataOutputStream output; //输出到文件的输出流 1<IF@__  
76Ho\}-U">  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） xJlf}LEyF  
public SiteFileFetch(SiteInfoBean bean) throws IOException Q+YYj  
{ K*NCIIDh  
siteInfoBean = bean; +`'=K ;{U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); gE;r;#Jt4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); cdY|z]B  
if(tmpFile.exists ()) Y)lYEhF  
{ V $Y=JK@  
bFirst = false; ]6#bp,  
read_nPos(); 41dB4Td5t  
} 1g<jr.  
else V'alzw7#  
{ xL&M8:  
nStartPos = new long[bean.getNSplitter()]; m?*}yM  
nEndPos = new long[bean.getNSplitter()]; \%[sv@P9s  
} Pk)>@F<  

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} GP<PU  
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public void run() X3mHg5zt  
{ xfegi$  
//获得文件长度 we?
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//分割文件
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//实例FileSplitterFetch Fw.df<  
//启动FileSplitterFetch线程 7H=V|Btnc  
//等待子线程返回 X?f\j"v  
try{ !pTi.3  
if(bFirst) b;xn0sDn#  
{ +V Oczl=  
nFileLength = getFileSize(); ?2q4dx0  
if(nFileLength == -1) -HQ(t  
{ 4 x|yzUx  
System.err.println("File Length is not known!"); fmgXh)=  
} G1tua"Px  
else if(nFileLength == -2) u7(<
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{ X^o0t^  
System.err.println("File is not access!"); 0Ba*"/U]t~  
} O n/q&h5  
else xu<oQBt  
{ (baBi9<P=  
for(int i=0;i<nStartPos.length;i++) (ay((|)  
{ 4"^v]&I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6N< snBmd  
} .(g"(fgF  
for(int i=0;i<nEndPos.length-1;i++) )i/x%^ca$  
{ <rI8O;\H  
nEndPos = nStartPos[i+1];  -^ceTzW+  
} /< -+*79G  
nEndPos[nEndPos.length-1] = nFileLength; c9O0YQ3&8  
} s:zz8oN  
} Um%$TGw5  
R1?LB"aN  
1
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//启动子线程 AFdBf6/"i  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Vw";< <0HZ  
for(int i=0;i<nStartPos.length;i++) |V-)3#c  
{
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l1UN.l'p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), '*=kt  
nStartPos,nEndPos,i); wOV}<.W  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L %20tm  
fileSplitterFetch.start(); UFPSQ  
} ItxC}qT  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AGMrBd|J{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z8JdA%YBM  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Qm@v}pD  
nEndPos = " + nFileLength); U2CCjAgRs  
// fileSplitterFetch[nPos.length-1].start(); fI }v}L^  
eh /QFm 4  
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//等待子线程结束 m\eYm;RVj  
//int count = 0; -F&*>?I  
//是否结束while循环 'Ivr=-  
boolean breakWhile = false; mw flx8  
wvz_)bN~A  
7-j=he/  
while(!bStop) ,}23  
{ h e1=  
write_nPos(); ss'`[QhR2  
Utility.sleep(500); S*'  
breakWhile = true; j-(k`w\  
VQ/Jz5^  
8dCa@r&tz  
for(int i=0;i<nStartPos.length;i++) k|;[)gE  
{ HOb0\X  
if(!fileSplitterFetch.bDownOver) 9
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{ gaVQ3NqF  
breakWhile = false; @ $2xiE.[  
break; w6G<&1iH  
} 'w`3( ':=  
} +&qj`hA-b  
if(breakWhile) U( (F<  
break; |n*<H|  
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,%U'>F?  
//count++; a[A*9%a  
//if(count>4) 3fhlMOm  
// siteStop(); 0})mCVBY  
} rF)[ Sed:T  
cRS2v--\-  
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System.err.println("文件下载结束！"); E;Q ,{{#  
} ctT6v
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catch(Exception e){e.printStackTrace ();} qcR"i+b  
} +5oK91o[y  
vj4n=F,Z  
jLCZ JSK  
//获得文件长度 {n-6e[  
public long getFileSize() p}9bZKyf  
{ 6U[bAp  
int nFileLength = -1; " twq#Alx  
try{ > ?<C+ZHh  
URL url = new URL(siteInfoBean.getSSiteURL()); az;o7[rI^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yp\sJc`  
httpConnection.setRequestProperty("User-Agent","NetFox"); e sDd>W  
5@
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int responseCode=httpConnection.getResponseCode(); !/wR[`s9w  
if(responseCode>=400) J)"g`)\2+  
{ TYN~c(  
processErrorCode(responseCode); mQqv{1  
return -2; //-2 represent access is error :Miri_l  
} eZk4$y  
3+d_5l;m)  
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String sHeader; cgF?[Z+x  
(OT&:WwW  
1GI/gc\  
for(int i=1;;i++) U6 $)e.FO  
{ X0e#w?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5*IfI+}  
//Utility.log(in.readLine()); ,+hH|$  
sHeader=httpConnection.getHeaderFieldKey(i); CF_pIfbaf  
if(sHeader!=null) 'v:%} qMv  
{ Z+]Uw  
if(sHeader.equals("Content-Length")) +ew9%={zB  
{ L2 ^-t7  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); XLxr@1   
break; ~T'Ri=  
} R0_O/o+{  
} R1lC_G]  
else !i77v, (#|  
break; ]v,>!~8r  
} 2!E@Gbhm5  
} FEzjP$  
catch(IOException e){e.printStackTrace ();} AHl1{* [  
catch(Exception e){e.printStackTrace ();} hA!kkNqV  
%?WR9}KU0  
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Utility.log(nFileLength); !=yNj6_f  
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return nFileLength; 67{>x[  
} AQ` `Dp  
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H 6~
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//保存下载信息（文件指针位置） i9Tq h  
private void write_nPos() Vim*4^[#L  
{ W{z{AxS  
try{ wSwDhOX=  
output = new DataOutputStream(new FileOutputStream(tmpFile)); CW9vC  
output.writeInt(nStartPos.length); )%T<Mw2u  
for(int i=0;i<nStartPos.length;i++) s%c
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{ eG05}  
// output.writeLong(nPos); cEc_S42Z  
output.writeLong(fileSplitterFetch.nStartPos);
;ZVT[gi*  
output.writeLong(fileSplitterFetch.nEndPos); !CO1I-yL  
} GL<u#[  
output.close(); |1[3RnGS  
} .\6q\7Ej  
catch(IOException e){e.printStackTrace ();} +91j 1?  
catch(Exception e){e.printStackTrace ();} <*'%Xgm  
} HZDeQx`*s  
_>k&M7OU4  
!/;/ X\d  
//读取保存的下载信息（文件指针位置） 2/ES.>K!.  
private void read_nPos() uz%<K(:Ov  
{ ZD(VH6<g%  
try{ b2<((H  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); , A@uSfC(  
int nCount = input.readInt(); B2/d%B  
nStartPos = new long[nCount]; a(Fx1`}  
nEndPos = new long[nCount]; <jwQ&fm)/R  
for(int i=0;i<nStartPos.length;i++) Jdc{H/10  
{ xxS>O%  
nStartPos = input.readLong(); <Mq vGXI  
nEndPos = input.readLong(); N3rq8Rk  
} suF<VJ)&s  
input.close(); G3wkqd
 
} "z6xS;  
catch(IOException e){e.printStackTrace ();} K}j["p<!  
catch(Exception e){e.printStackTrace ();} j2GTo~muq  
} fb*h.6^y9  
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private void processErrorCode(int nErrorCode) =Sp+$:q*  
{ 9(AY7]6  
System.err.println("Error Code : " + nErrorCode); e\7AtlW"  
} # X`t~Y'  
5"WI^"6b:  
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//停止文件下载 9 7Ua,  
public void siteStop() =v:}{~M^$  
{ \'9(zbvz9  
bStop = true; j' }4ZwEh  
for(int i=0;i<nStartPos.length;i++) `37%|e3bQ  
fileSplitterFetch.splitterStop(); 7zcmv"`  
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} e,DRQ2AU  
} O/b1^ Y   
//负责部分文件的抓取 3\2^LILLO  
**FileSplitterFetch.java 1/tyne=m  
*/ K0'= O  
package NetFox; 9'Cu9nR  
%$6?em_  
#DA,*  
import java.io.*; ZE[NQ8  
import java.net.*; &ev#C%Nu  
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public class FileSplitterFetch extends Thread { %{B4M#~  
U7xKu75G1  
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String sURL; //File URL =J0r,dR  
long nStartPos; //File Snippet Start Position :qvA'.L/;z  
long nEndPos; //File Snippet End Position 4Dw| I${O  
int nThreadID; //Thread's ID UWW'[gEP1  
boolean bDownOver = false; //Downing is over _+ERX[i  
boolean bStop = false; //Stop identical x }.&?m  
FileAccessI fileAccessI = null; //File Access interface ,Yu2K`  
MZ%S3'  
S76xEL  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Z5`U+ (  
{ xA>3]<O  
this.sURL = sURL; <Q@{6  
this.nStartPos = nStart; ;]VLA9dC  
this.nEndPos = nEnd; M!Ywjvw*)3  
nThreadID = id; $]~|W3\G  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )(h<vo)-zX  
} ,!bcm  
SN5Z@kK  
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public void run() 98Im/v  
{ fiQ/ &]|5  
while(nStartPos < nEndPos && !bStop) v%)=!T,  
{ ',s{N9  
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try{ ,ik\MSS  
URL url = new URL(sURL); F>ps&h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 
DG/<#SCF  
httpConnection.setRequestProperty("User-Agent","NetFox"); jF6[+bW<  
String sProperty = "bytes="+nStartPos+"-"; xz){RkVzP  
httpConnection.setRequestProperty("RANGE",sProperty); X({R+  
Utility.log(sProperty); }b/G{92  
;|.IUXEgcF  
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InputStream input = httpConnection.getInputStream(); XB+Juk&d  
//logResponseHead(httpConnection); Jm3iYR+,  
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Ombvp;  
byte[] b = new byte[1024]; {3G2-$yb  
int nRead; }O8#4-E_Ji  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) o%l|16DR  
{ ^w~Utx4  
nStartPos += fileAccessI.write(b,0,nRead); k2DBm q;  
//if(nThreadID == 1) 4Dv42fO  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ILT.yxV  
} 5u
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3k* U/*  
FQw@@  
Utility.log("Thread " + nThreadID + " is over!"); \"Aw ATQ  
bDownOver = true; 3t$)saQR  
//nPos = fileAccessI.write (b,0,nRead); YCu9dBeVS  
} (\ Gs7  
catch(Exception e){e.printStackTrace ();} ^vr`t9EE  
} -MItZ  
} ~MW_=6U  
Jtl[9qe#]  
8\rHSsP  
//打印回应的头信息 pu5-=QN  
public void logResponseHead(HttpURLConnection con) S@eI3PkE  
{ z=a{;1A  
for(int i=1;;i++) 2w67>w\  
{ ?iaD;:'qE  
String header=con.getHeaderFieldKey(i); S1W(]%0/  
if(header!=null) -{a&Zkz>V  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); v`9n'+h-c6  
Utility.log(header+" : "+con.getHeaderField(header)); <rFKJ^B  
else r?wE;gH  
break; -,}ppTG  
} 'E~[I"0  
} a[Oi  
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9 e0Oj3!B  
public void splitterStop() ompkDl\E  
{ 2B&|0&WI  
bStop = true; s(M8 Y  
} x)!NB99(tC  
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} #ZPy&GIr  
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\k)(:[^FY  
/* |csR"DOqz  
**FileAccess.java mdPEF)-  
*//文件访问(定位，写) PV/SzfvIq  
package NetFox; Mwd(?o  
import java.io.*; 1U< g  
m\?H <o0  
 QKtTy>5  
public class FileAccessI implements Serializable{ k-a3oLCR,  
,1&</R_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 d}RR!i`<N  
RandomAccessFile oSavedFile; 4]3(Vyh`  
long nPos; 63n<4VSH  
Vpsv@\@J>  
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public FileAccessI() throws IOException "8h7"WR  
{ 2q,> *B?  
this("",0); #iAEcC0k5  
} Wf>scl`s  
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?\
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public FileAccessI(String sName,long nPos) throws IOException #Jqa_$\.  
{ ]:vo"{*C  
oSavedFile = new RandomAccessFile(sName,"rw"); 'vUx4s  
this.nPos = nPos; x-HN]quhe  
oSavedFile.seek(nPos); \%+5p"Z<  
} uRfFPOYH  
dy^zOqc  
BR [3i}Ud  
public synchronized int write(byte[] b,int nStart,int nLen) c})f&Z@<  
{ wA;C
j  
int n = -1; Kt3]r:&J  
try{ 9k[>(LC  
oSavedFile.write(b,nStart,nLen); wc#E:GJcK  
n = nLen; X,"(G}KUA  
} mIX[HDy:V$  
catch(IOException e) Xv'5%o^i*  
{ .#[==  
e.printStackTrace (); K6l{wyMb|  
} ~t-!{F  
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return n; @?r[ $Ea1M  
}  N\9Wxz$  
<|MF\D'  
QZs ]'*=#  
} a{FCg%vD)  
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}hy, }2(8  
/*  F6\Hqv  
**SiteInfoBean.java QFtf.")[.  
*/ <4|/AF*>  
package NetFox; mWPA]g(  
l@OY8z-_  
wfXm(RYM  
public class SiteInfoBean {  nW*D  
E'O[E=  
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private String sSiteURL; //Site's URL bYKe5y=  
private String sFilePath; //Saved File's Path n$oHr  
private String sFileName; //Saved File's Name 9Oe~e
 
private int nSplitter; //Count of Splited Downloading File q/lQEfR  
?' :v):J}  
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public SiteInfoBean() jJK`+J,i}X  
{//nSplitter的缺省值为5 Q'B2!9=LB  
//default value of nSplitter is 5 %P2l@}?a  
this("","","",5); = olmBXn/  
} yxx'g+D*  
iir]M`A.-  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) tr t^o  
{ e 1$<,.>  
sSiteURL= sURL; aF41?.s  
sFilePath = sPath; @z-%:J/$  
sFileName = sName; ^L@2%}6b`  
this.nSplitter = nSpiltter; e: aa  
d~F4  
.*(xkJI3  
} %HAforH  
/5$;W'I  
vk&6L%_~a  
public String getSSiteURL() ^I CSs]}1  
{ +'VSD`BR  
return sSiteURL; E
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} !
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%A^V@0K3  
15X.gx  
public void setSSiteURL(String value) NlG~{rfI  
{ ~]_U!r[FA  
sSiteURL = value; Ump$N#  
} gZHuyp(B  
%Y:"5fH  
0Kytg\p}  
public String getSFilePath() lIUaGz|  
{ 2]}4)_&d<e  
return sFilePath; s1GR!*z>  
} D02(6|  
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!w;oVPNg  
public void setSFilePath(String value) R0A|}Ee*  
{ N7 FndB5%  
sFilePath = value; ]~K&b96(  
} ~EL3I  
MOia]5
 
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public String getSFileName() V*<`!w  
{ fFYfb4
o  
return sFileName; "!w#E6gU  
} e"D%eFkDW  
N|@jHxy  
o^ zrF  
public void setSFileName(String value) J6[V7R[\  
{ {KGEv%  
sFileName = value; tSVWO]<  
} [Xyu_I-c  
U5RLM_a@M  
>_J9D?3S  
public int getNSplitter() SIridZ*%  
{ $Vp*,oRL  
return nSplitter; 90[6PSXk  
} [2$mo;E?  
?`lD|~  
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public void setNSplitter(int nCount) B{ Ab#  
{ [p+-]V  
nSplitter = nCount; 9,wD  
} 4^Y{ BS fF  
} 7M/v[dwL  
m!K`?P]:N  
M '#a.z%  
/* TT@U_^o  
**Utility.java _1,hO?TK  
*/ +6`+Q2qi  
package NetFox; fg)VO6Wo&  
PS}'LhZ  
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public class Utility { xfa-  
4`GOBX1b.y  
~NMx:PP  
public Utility() )GYnQoV4  
{ 2{Y~jYt{h  
z?^oy.  
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} ZfMs6`Wv 1  
Yu$QL@  
//线程睡眠 `y|_hb  
public static void sleep(int nSecond) Uv m:`e~?  
{ ZXIw^!8@/  
try{ oo\7\b#Jx  
Thread.sleep(nSecond); X- ZZLl#  
} V,h}l"  
catch(Exception e) (^NYC$ZxM=  
{ SK*z4p  
e.printStackTrace (); 3;RQ\{eM  
} o(k{Ed  
} VIHuo,  
F[v:&fle  
//日志 BW:HKH.k  
public static void log(String sMsg) )dd1B>ej]  
{ lvsj4cT  
System.err.println(sMsg); !-t,r%CG  
} Vw|P;LLl`  
M#_|WL~  
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public static void log(int sMsg) f{.4#C'  
{ q{ [!" ,  
System.err.println(sMsg); -VeCX]  
} xg}Q~,:  
} bksv2@ar  
?I[*{}@n"  
: eCeJ~&E  
/* Sv_Nb>  
**TestMethod.java o"6 2~  
*/  W,|+Dl  
package NetFox; -.Blj<2ah  
_%[po%]  
YF)]B|I  
public class TestMethod { mqj-/DN6*  
~Pj q
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\h"U+Bv7  
public TestMethod() QC?~$>h!?  
{ ///xx/weblogic60b2_win.exe w_f.\\1r  
try{ ]rv4O@||w  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %vv`Vx2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Sx[ eX,q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); P6&%`$  
fileFetch.start(); egvb#:zW?  
} R RE8|%p;B  
catch(Exception e){e.printStackTrace ();} Sbl=U  
n)~*B
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} `BQv;NtP  
Z\$M)

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public static void main(String[] args) o@BV&|  
{ D#AqZS>B  
new TestMethod(); Q~tXT_  
} m8=n`XI  
} ?=ffv]v|  
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