http断点续传简单实现（java)

/* hGiz)v~  
**SiteFileFetch.java %'[&U#-  
*/ 1 5A*7|  
package NetFox; _1U1(^)  
import java.io.*; n5{Xj:}  
import java.net.*; Uh][@35 p  
n_'s=]~  
=C~/7N,lW]  
public class SiteFileFetch extends Thread { b!)<-|IK  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Zfy
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long[] nStartPos; //开始位置 +"1NC\<
*  
long[] nEndPos; //结束位置 {l |E:>Q2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 T8^5=/  
long nFileLength; //文件长度 < P`u}  
boolean bFirst = true; //是否第一次取文件 4Z/f@ZD  
boolean bStop = false; //停止标志 ",!1m7[wF  
File tmpFile; //文件下载的临时信息 :sCqjz  
DataOutputStream output; //输出到文件的输出流 %JLk$sP9y`  
_U/!4A  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） EOm:!D\  
public SiteFileFetch(SiteInfoBean bean) throws IOException IKi5 v~bE  
{ B9wPU1  
siteInfoBean = bean; 8cA~R-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); aXL{TD:]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {RF-sqce  
if(tmpFile.exists ()) &B|D;|7H  
{ zD<or&6  
bFirst = false; $]8
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read_nPos(); $jg*pmR-  
} DZ_lW  
else |_yYLYH'   
{ O9r>E3-q  
nStartPos = new long[bean.getNSplitter()]; L:z?Zt)|  
nEndPos = new long[bean.getNSplitter()]; rfq;%C  
} D&S26jrZ  
# 0Lf<NZ  
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} /IsS;0K%L  
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{6}eN|4~#  
public void run() =MvjLh"s  
{ ,~"$k[M  
//获得文件长度 f/V 2f].  
//分割文件 J.8IwN1E  
//实例FileSplitterFetch ak;*W  
//启动FileSplitterFetch线程 A]DTUdL  
//等待子线程返回 0$-xw  
try{ !=N"vD*  
if(bFirst) fXcm|U,ho  
{ Lliqj1&  
nFileLength = getFileSize(); k70|'*Kh  
if(nFileLength == -1) B` k\EL'  
{ HB7;0yt`:  
System.err.println("File Length is not known!"); 1n@8Kv  
} PnoPbk[<  
else if(nFileLength == -2) Yc'kvj)_M  
{ 2/0v B>  
System.err.println("File is not access!"); n-%s8aaVf  
} ~}+Hgi  
else o0pII )v  
{ qv@$ZLR  
for(int i=0;i<nStartPos.length;i++) ; k)@DX  
{ Y_
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); [3!~PR]  
} d.P\fPSD  
for(int i=0;i<nEndPos.length-1;i++) l'3pQ;  
{ zA1lca0HK  
nEndPos = nStartPos[i+1]; M`l.t -ut  
} *q1%IJ  
nEndPos[nEndPos.length-1] = nFileLength; ;dzL}@we  
} -k"^o!p  
} }|XtypbL  
Q^#;
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//启动子线程 V?=8".GiX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VL*ovD%-  
for(int i=0;i<nStartPos.length;i++) Et/&^&=\-  
{ !Uq^7Mw  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @0SC"CqM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), TEaJG9RU>v  
nStartPos,nEndPos,i); uNHF'?X  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R>(@ZM&  
fileSplitterFetch.start(); 1Y]TA3:  
} /=gOa\k|p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2^l[(N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =hMY2D  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", R<=zCE`:  
nEndPos = " + nFileLength); ]~E0gsq  
// fileSplitterFetch[nPos.length-1].start(); ivW(*c  
tz&y*e&  
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//等待子线程结束 d{E}6)1=  
//int count = 0; x*Y@Q?`>5W  
//是否结束while循环 $9ky{T?YG  
boolean breakWhile = false; U~ck!\0&T  
9s_,crq5  
b%S62(qP  
while(!bStop) =-}[^u1  
{ fOMvj%T@2  
write_nPos(); zBe8,, e  
Utility.sleep(500); `IY/9'vT  
breakWhile = true; n8DxB@DI  
K
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|K|h+fgG6*  
for(int i=0;i<nStartPos.length;i++) g'|MA~4yB  
{ 3dRr/Ilc  
if(!fileSplitterFetch.bDownOver) cJL'$`gWf  
{ 4`8<   
breakWhile = false; ?A )hN8  
break; &[;HYgp  
} 6A=8+R'`F  
} [/BE8]M~  
if(breakWhile) Y>&Ew*Y  
break; Z"
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 .fdL&z  
_X'"w|0  
//count++; PfZ+PqS  
//if(count>4) [Ts"OPb%~  
// siteStop(); hjQ~uqbg  
} I*`*Q$  
h`H,a7  
+fnK/%b  
System.err.println("文件下载结束！"); V.{H9n]IO  
} z$kenhFG/  
catch(Exception e){e.printStackTrace ();} J:kmqk!  
} \l@,B +)  
xu'yVt9RC  
Y)}Rb6qGW  
//获得文件长度 s$a09x  
public long getFileSize() iIP8`! O  
{ {je-I9%OK  
int nFileLength = -1; Qr$;AZ G  
try{ "^1L'4'S  
URL url = new URL(siteInfoBean.getSSiteURL()); +r<0zh,n.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V}zEK0n(6  
httpConnection.setRequestProperty("User-Agent","NetFox"); (S v~2  
$&2UTczp  
V,[d66H=N  
int responseCode=httpConnection.getResponseCode(); wX*K]VMn  
if(responseCode>=400) +(+Itmx2&  
{ 7H|$4;
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processErrorCode(responseCode); 5Fz.Y}  
return -2; //-2 represent access is error Q"7Gy<  
} (~J^3O]Fo  
g=e71DXG2  
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String sHeader; _{ZqO;[u  
%
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for(int i=1;;i++) &RTX6%'KY  
{ z1
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |eWjYGwJa  
//Utility.log(in.readLine()); mSo_} je(  
sHeader=httpConnection.getHeaderFieldKey(i); ;IpT} ,  
if(sHeader!=null) UDL RCS8i  
{ fhCc! \  
if(sHeader.equals("Content-Length")) KW7UUXL  
{ cDI [PJ9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); c?%(DpE  
break; &wB\ ~Ie-  
} :(H>2xS,s  
} @GvztVYo  
else Z*FrB5
8  
break; K_ci_g":  
} T =2=k&|  
} Vy|6E#U  
catch(IOException e){e.printStackTrace ();} oaK%Ww6~  
catch(Exception e){e.printStackTrace ();} t>uN'oCyC  
=Z+nX0qF  
7YAIA%8  
Utility.log(nFileLength); y7|P-3[ 4w  
"hQ_sgz[Z  
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return nFileLength; yA3wtm/?  
} JXj8Br?Z@  
"{D|@
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h48SItY  
//保存下载信息（文件指针位置） >pr=|$zk=  
private void write_nPos() 36n>jS&  
{ !L95^g  
try{ h)me\U7UC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2mq$H_  
output.writeInt(nStartPos.length); AZ{^o4<q  
for(int i=0;i<nStartPos.length;i++) #"49fMi/  
{ raQ7.7  
// output.writeLong(nPos); x+G0J8cW  
output.writeLong(fileSplitterFetch.nStartPos); 9RWkm%?  
output.writeLong(fileSplitterFetch.nEndPos); -$,%f?  
} 3bNIZ#`|MB  
output.close(); (4%YHS8  
} Ve/xnn]'  
catch(IOException e){e.printStackTrace ();} 5~yNqC  
catch(Exception e){e.printStackTrace ();} x[Wwq=~  
} OK{xuX8u  
^`D=GF^tX  
L.=w?%:H=  
//读取保存的下载信息（文件指针位置） g5q$A9.Jl  
private void read_nPos() U-^[lWn[@4  
{ tM#lFmdd\P  
try{ @;?T~^nGj  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _0 m\[t.  
int nCount = input.readInt(); )=DGdIEt  
nStartPos = new long[nCount]; nJbbzQ,e  
nEndPos = new long[nCount]; (S^8UV  
for(int i=0;i<nStartPos.length;i++) O MX-_\")  
{ nL?oTze*p  
nStartPos = input.readLong(); H-p
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nEndPos = input.readLong(); K)_WL]RJ.4  
} 9V.u-^o&  
input.close(); ,2]X}&{i  
} O$ HBO  
catch(IOException e){e.printStackTrace ();} z7-k`(l4  
catch(Exception e){e.printStackTrace ();} 2
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} O0PJ6:9P  
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private void processErrorCode(int nErrorCode) y4Er@8I`  
{ D\H/
  
System.err.println("Error Code : " + nErrorCode); ayBRWT0  
} AE@NOM7u  
"Y=+Ls(3o(  
>5 b/or  
//停止文件下载 BtY%r7^o  
public void siteStop() 5%}wV,Y  
{ 6yy;JQAke  
bStop = true; :L 3&FA  
for(int i=0;i<nStartPos.length;i++) pZZf[p^s
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fileSplitterFetch.splitterStop(); vJ`.iRU|  
;<Km3  
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} 3u33a"nL8  
} Y$-3v.  
//负责部分文件的抓取 9,]5v+  
**FileSplitterFetch.java ?tg  y|  
*/ \VSATL:]  
package NetFox; -@&1`@):{  
6/ `.(fL1  
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import java.io.*; HvxJj+X9  
import java.net.*; q_Lo3|t i  
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public class FileSplitterFetch extends Thread { S.|FL%;  
nNmsr=y5  
=IKEb#R/  
String sURL; //File URL  oK9'  
long nStartPos; //File Snippet Start Position Yct5V,X^  
long nEndPos; //File Snippet End Position  st'D
 
int nThreadID; //Thread's ID gf)t)-E  
boolean bDownOver = false; //Downing is over j6ut}Uq  
boolean bStop = false; //Stop identical jKIc09H|  
FileAccessI fileAccessI = null; //File Access interface 4Tct  
V|MY!uV  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException W9zE{)Sc~  
{ iK_c.b  
this.sURL = sURL; MK}-<&v  
this.nStartPos = nStart; NV r0M?`4  
this.nEndPos = nEnd; +{53a_q  
nThreadID = id; "gW7<ilw   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {0YAzZ7  
} N{d@^Yj  
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public void run() fYrGpW(`  
{ (ozb%a#B  
while(nStartPos < nEndPos && !bStop) o5aLUWi-  
{ c3 &m9zC  
;pRcVL_4  
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try{ )$x_!=@1  
URL url = new URL(sURL); k6\^p;!Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); GQ_Ia\  
httpConnection.setRequestProperty("User-Agent","NetFox"); SJgY  
String sProperty = "bytes="+nStartPos+"-"; @o
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httpConnection.setRequestProperty("RANGE",sProperty); uM(UO,X  
Utility.log(sProperty); "zZIS6j  
[{&jr]w`|  
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InputStream input = httpConnection.getInputStream(); I]}>|  
//logResponseHead(httpConnection); 8Og3yFx[rt  
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byte[] b = new byte[1024]; sP$Ks#/  
int nRead; "t(wG{RxY  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2}t&iG|0/  
{ Ov9Q?8KzM  
nStartPos += fileAccessI.write(b,0,nRead); _ :^7a3I  
//if(nThreadID == 1) w36(p{#vp  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w>~M}Ahj  
} 8)0L2KL'  
l*7?Y7FK  
+'03>!V  
Utility.log("Thread " + nThreadID + " is over!"); K6pR8z*?  
bDownOver = true; g.Hio.fVd  
//nPos = fileAccessI.write (b,0,nRead); :wgfW .w  
} -g`IH-B  
catch(Exception e){e.printStackTrace ();} Q*O<@   
} v@u<Ww;=@  
} O%1/r*  
q'(z #h,cv  
{)K](S ~  
//打印回应的头信息 FEm=w2  
public void logResponseHead(HttpURLConnection con) =7ydk"xM*  
{ 0-2"FdeQU  
for(int i=1;;i++) h
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{ yFpySvj}  
String header=con.getHeaderFieldKey(i); :mv`\  
if(header!=null) _dU P7H (  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (v#pj8aE  
Utility.log(header+" : "+con.getHeaderField(header)); Rs$5PdH  
else IjZ@U%g@;  
break; =l`OHTg  
} W8aU"_  
} xRX>|S  
>#N[GrJAE  
h[=nx^  
public void splitterStop() 6f]rQ9  
{ yBn_Kd  
bStop = true; jM__{z  
} d(L{!mm  
@"1}16b#f  
d#T?Q_3b  
} [BXyi  
uu}-"/<~7  

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/* 30 7fBa  
**FileAccess.java  ^Omfe  
*//文件访问(定位，写) |f NMs  
package NetFox; |Cf mcz(56  
import java.io.*; {j6g@Vd6lx  
-i_En^Fi  
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public class FileAccessI implements Serializable{ 5N1 K~".  
Vm!i  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 eoJ]4-WFq  
RandomAccessFile oSavedFile; cgyo_ k  
long nPos; 4 iH&:Al  
v.`+I-\.z)  
:t2B^})\  
public FileAccessI() throws IOException /PC`0/b  
{ #%cR%Z  
this("",0); F1}  
} 'TX M{RGw  
.xpmp6-  
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public FileAccessI(String sName,long nPos) throws IOException :dDxxrs"  
{ aIu2>  
oSavedFile = new RandomAccessFile(sName,"rw"); my,x9UPs  
this.nPos = nPos; j-* TXog  
oSavedFile.seek(nPos); ahp1!=Z-=  
} &|=?acv  
4 =Fg!Eu<  
37KU~9-A  
public synchronized int write(byte[] b,int nStart,int nLen) T}2:.Hk:N  
{ ; J2-rh  
int n = -1; lO&cCV;  
try{ BE%Z\E[[m  
oSavedFile.write(b,nStart,nLen); '4
9L(>.  
n = nLen; !`C%Fkq  
} e\~l!f'z  
catch(IOException e) {8ECNQ[]  
{ Uh\]?G[G  
e.printStackTrace (); <bX 1,}?  
} CZfE |T~  
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#HDesen  
return n; AP ;
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} )KE_t^$  
;z0"Ox=7  
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} Bbs5f@E  
vXf:~G]  
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/* i+RD]QL  
**SiteInfoBean.java 'Q`C[*c  
*/ X X&K=<,Ja  
package NetFox; ux&:Rw\  
) MBS  
}s6G!v^2""  
public class SiteInfoBean { ;/aB)JZ5=  
O=`o'%K<  
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private String sSiteURL; //Site's URL @tQ2E}psP,  
private String sFilePath; //Saved File's Path
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private String sFileName; //Saved File's Name CKN8z  
private int nSplitter; //Count of Splited Downloading File )rbc;{.  
r\bq[9dX>  
] ?9t-  
public SiteInfoBean() c85O_J  
{//nSplitter的缺省值为5 r_=p,#}#  
//default value of nSplitter is 5 .m!s". ?[  
this("","","",5); sZEgsrJh  
} /KP_Vc:g2_  
xcnt?%%M  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) EaCZx  
{ cb4b,Ri  
sSiteURL= sURL; 1{7_ 
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sFilePath = sPath; =<>pKQ)[  
sFileName = sName; j aD!  
this.nSplitter = nSpiltter; -Y2&A$cM  
v0u\xX[H;  
!`Xt8q\r  
} oc=tI@W  
hOl=W |)v  
`:R-[>5P8  
public String getSSiteURL() F\Y,JUn[G  
{ |zb`&tv}  
return sSiteURL; oX#9RW/ >I  
} R;.d/U|av  
9g4QVo|  
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public void setSSiteURL(String value) 7Qt2gf  
{ /Q]:Uf.J  
sSiteURL = value; Ef-a4Pi  
} BQuRHi IV  
f{f_g8f[
 
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public String getSFilePath() CR.bMF}  
{ `M,Nd'5&|  
return sFilePath; xV?*!m$V%R  
} z6Fun  
yX3PUO9  
phe"JNML  
public void setSFilePath(String value) IF& PGo  
{ G1p43  
sFilePath = value; F"Uh/EO<  
} U~Xf=f_Q$  
!>q?dhw@  
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public String getSFileName() df!+T0  
{ FSFFk~  
return sFileName; N JXa_&_  
} jjYM3LQcdP  
_qEWu Do  
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public void setSFileName(String value) #!wsD7;  
{ otoBb^Mz  
sFileName = value; !+5C{Hs2  
} a (P^e)<  
<r0.ppgY  
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public int getNSplitter() 9=H}yiJz  
{ r+SEw ;  
return nSplitter; _`slkwP.  
} d\\r_bGW  
Ck:#1-t8{  
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public void setNSplitter(int nCount) >7"$}5d  
{ c{^i$  
nSplitter = nCount; E
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} 7&=-a|k~  
} p| Vmdnb  
;HR 6X  
`8mD7xsg$  
/* OTnu{<.a  
**Utility.java r[6#G2  
*/ 2%`^(\y  
package NetFox; -
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=DGn,i9  
44Q6vb?  
public class Utility { bcUC4g\9N  
qPL^zM+  
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public Utility() H&~5sEGa  
{ B>{|'z?%>  
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} lv=yz\  
20$F$YYuk  
//线程睡眠 c*Eok?O  
public static void sleep(int nSecond) @47[vhE  
{ )>-77\  
try{ J'I1,5(  
Thread.sleep(nSecond); tniPEmeS  
} 8f /T!5  
catch(Exception e) fui4

@  
{ s"pR+)jf1D  
e.printStackTrace (); 3Ne9%"  
} |De!ti  
} }pbBo2  
^2C0oX  
//日志 XRClBTKF  
public static void log(String sMsg) x>U1t!'  
{ Pd)K^;em  
System.err.println(sMsg); z\xiACIc  
} D?iy.Dg  
b*btkaVue  
2N L:\%wz  
public static void log(int sMsg) >{phyBy
I  
{ NvQY7C  
System.err.println(sMsg); |WD,\=J2  
} pe\Txg
6  
} IyrZez  
+io;K]C  
YRg=yVo2  
/* V}vl2o
  
**TestMethod.java k7:GS
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*/ +^/Nil  
package NetFox; R88(dEK  
,maAw}=  
"[%;B0J  
public class TestMethod { uAW*5 `[  
u5u0*c  
B, QC-Tn  
public TestMethod() A8_\2'b  
{ ///xx/weblogic60b2_win.exe kS@9c _3S  
try{ I>A^5nk  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); bs<WH`P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Paae-EmC  
SiteFileFetch fileFetch = new SiteFileFetch(bean); U@o2gjGN  
fileFetch.start(); K*([9VZ  
} _7-"VoX  
catch(Exception e){e.printStackTrace ();} QVnO
  
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} .Ws iOJU  
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,Hik(22  
public static void main(String[] args) IeRl6r%:  
{ ""25ay  
new TestMethod(); E[SV*1)  
} 4@/q_*3o  
} H B::0l<  
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