http断点续传简单实现（java)

/* -dZ7;n5&_  
**SiteFileFetch.java Tf<1Z{9  
*/ gI<TfcC  
package NetFox; ON\_9\kv  
import java.io.*; tJ i#bg%  
import java.net.*; E9YR *P4$  
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public class SiteFileFetch extends Thread { 5iwJdm  

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SiteInfoBean siteInfoBean = null; //文件信息Bean X@2[!%n
m  
long[] nStartPos; //开始位置 lqT
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long[] nEndPos; //结束位置 B{PI&a9~s%  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 CMI%jyiX
 
long nFileLength; //文件长度 "FwbhD0Gb  
boolean bFirst = true; //是否第一次取文件 #ih(I7prH  
boolean bStop = false; //停止标志 2I* 7?`  
File tmpFile; //文件下载的临时信息 odD^xg"L  
DataOutputStream output; //输出到文件的输出流 J 6D?$  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4RGEg;]S  
public SiteFileFetch(SiteInfoBean bean) throws IOException  pQKR  
{ $h"tg9L^)  
siteInfoBean = bean; waz)jEk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }K!}6?17T  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); l\I#^N  
if(tmpFile.exists ()) N.vt5WP  
{ /'ccFm2  
bFirst = false; ELZCrh6*  
read_nPos(); ^2rNty,nH  
} y0k*iS e  
else ,]+P#eXgE  
{
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nStartPos = new long[bean.getNSplitter()]; $!)Sgb  
nEndPos = new long[bean.getNSplitter()]; }RowAGWL  
} B2w\  
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) jv]Oz  
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} ?5_~Kn%2  
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public void run() bi;?)7p&ZY  
{ %5Hsd  
//获得文件长度 >qk[/\^O  
//分割文件 mrX 2w  
//实例FileSplitterFetch @*
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//启动FileSplitterFetch线程 1
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//等待子线程返回 1RpTI7  
try{ PeT _Ty  
if(bFirst) ()a(PvEO
 
{ yr?*{;  
nFileLength = getFileSize(); mN
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if(nFileLength == -1) l$N b1&  
{ +RWP;rk  
System.err.println("File Length is not known!"); Z M_ 6A1  
} 03$-U0.;-  
else if(nFileLength == -2) {G$I|<MD2T  
{ __o`+^FS  
System.err.println("File is not access!"); BB@I|)9O(  
} E^B*:w3  
else Ww-%s9N<  
{ [-C-+jC  
for(int i=0;i<nStartPos.length;i++) hiO:VA  
{ ]k~Vh[[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); U'(}emh}  
} ii&{gC  
for(int i=0;i<nEndPos.length-1;i++) swNJ\m  
{ $.{CA-~%[  
nEndPos = nStartPos[i+1]; O92a*)  
} 7yp7`|,p  
nEndPos[nEndPos.length-1] = nFileLength; ]4~- z3=y  
} ."b=dkx  
} #!V [(/  
NJK?5{H'  
Pl^-]~  
//启动子线程 *%
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 94C)63V  
for(int i=0;i<nStartPos.length;i++) ZfalB  
{ at7|r\`?-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FD>j\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), AdBF$nn[  
nStartPos,nEndPos,i); ER,,K._?B  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); iC- ?F cA  
fileSplitterFetch.start(); 18JhC*in  
} Y^5X>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Jg#L8>p1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [ox!MQ+s  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6ExUNp @U>  
nEndPos = " + nFileLength); V"":_`1VW  
// fileSplitterFetch[nPos.length-1].start(); Z-[nHSf  
yH_L<n  
o%#Z  
//等待子线程结束 {MX_t/o=f  
//int count = 0; /E>z8J$  
//是否结束while循环 %4QCUc*lr  
boolean breakWhile = false; !R,9Pg*Ey  
-
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^aVoH/q*C  
while(!bStop) =w&%29BYq  
{ <}'hkEh{d=  
write_nPos(); $$C5Q;7w!  
Utility.sleep(500); INwc@XB  
breakWhile = true; ~N+lI\K  
FI@2KM  
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for(int i=0;i<nStartPos.length;i++) n=v4m_e  
{ :&$4&\_F  
if(!fileSplitterFetch.bDownOver) {#M=gDhbX  
{
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breakWhile = false; }D.?O,ue  
break; kfb+OE:7  
} wd*i&ooQ*L  
} g3{)AX[Uy  
if(breakWhile) aM'0O![d  
break; bu"Jb4_a>  
[o&Vr\.$  
L;.
6j*E*  
//count++; ~h-G  
//if(count>4) cqeId&Cg  
// siteStop(); 2YK4SL  
} M"F?'zTkJ  
z.23i^Q  
EVmQ"PKL'  
System.err.println("文件下载结束！"); 2a*1q#MpAt  
} s<0yQ-=.?N  
catch(Exception e){e.printStackTrace ();} }4xxge?r  
} Z91gAy^z<  
g92M\5 x9  
7-Rn{"5  
//获得文件长度 {neE(0c  
public long getFileSize() C|"T!1MlY4  
{ *sf9(%j  
int nFileLength = -1; xt +fuL  
try{ "
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URL url = new URL(siteInfoBean.getSSiteURL()); ~bT0gIc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d%9I*Qo0,  
httpConnection.setRequestProperty("User-Agent","NetFox"); "n '*_rh>+  
dv4)fG]W;_  
If6wkY6sR  
int responseCode=httpConnection.getResponseCode(); f4
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if(responseCode>=400) =Z/'|;Vd_x  
{ ;~z>GJox  
processErrorCode(responseCode); =pWpHbB.  
return -2; //-2 represent access is error =B1t?("  
} H*|Bukgt/M  
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V3  
v)N6ZOj*C  
String sHeader; DS>s_3V  
&m8B%9w  
%H<w.]>  
for(int i=1;;i++) e^~t52]  
{ K *vNv4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $';'MoS  
//Utility.log(in.readLine()); #CV(F$\1{  
sHeader=httpConnection.getHeaderFieldKey(i); hl}#bZ8]  
if(sHeader!=null) o)}b Fw  
{ \Qk:\aL
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if(sHeader.equals("Content-Length")) Fh
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{ 1sc #!^Oo  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); tP!sOvQ:  
break; |BH, H  
} 1I3u~J3]/  
} pI(FUoP^  
else 1b3Lan_2  
break; 8SAz,m!W)  
} 58e{WC  
} &[*<>  
catch(IOException e){e.printStackTrace ();} e@]cI/j  
catch(Exception e){e.printStackTrace ();} 
7M;Y#=sR  

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Utility.log(nFileLength); rLL;NTN+/  
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return nFileLength; qWE
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} =j;o, J:(  
^"buF\3L  
T82=R@7  
//保存下载信息（文件指针位置） n+uq|sYVa  
private void write_nPos() LiV]!*9$KG  
{ mz\m^g3  
try{ Z,iklB-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5,Q('t#J  
output.writeInt(nStartPos.length); *DNH_8m  
for(int i=0;i<nStartPos.length;i++)
gu:..'V  
{ ae!_u \$  
// output.writeLong(nPos); @XIwp2A{+  
output.writeLong(fileSplitterFetch.nStartPos); !Aw.f!  
output.writeLong(fileSplitterFetch.nEndPos); R:ar85F  
} V|a59[y?  
output.close(); Y(A?ib~K  
} T3?kabbF  
catch(IOException e){e.printStackTrace ();} IBF>4qm"  
catch(Exception e){e.printStackTrace ();} D1g1"^~g  
} `HJwwKd  
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//读取保存的下载信息（文件指针位置） uPo>?hpq+  
private void read_nPos() 3
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{ 3t_5Xacj  
try{ ]B7t9l  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }Ql;%7  
int nCount = input.readInt(); X@D3  
nStartPos = new long[nCount]; A6U6SvM;  
nEndPos = new long[nCount]; n&V(c&C  
for(int i=0;i<nStartPos.length;i++) gTQ6B,`/8  
{ <'vM+Lk  
nStartPos = input.readLong();
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nEndPos = input.readLong(); X0P$r6 ;  
} ]D]K_`!K  
input.close(); m76]INq  
} qzmZ/z96  
catch(IOException e){e.printStackTrace ();} d8r
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catch(Exception e){e.printStackTrace ();} 4Sl^cKb$7  
} 3
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private void processErrorCode(int nErrorCode) #]'V#[;~  
{ pKJ[e@E^  
System.err.println("Error Code : " + nErrorCode); "bO]  
} q_K1L  
6x7=0}'  
[&4y@  
//停止文件下载 \G"/Myi  
public void siteStop() FG(`&S+,  
{ <;T7qEIlo  
bStop = true; G?g7G,|d  
for(int i=0;i<nStartPos.length;i++) $R5-JvJJH  
fileSplitterFetch.splitterStop(); rTJWftH!  
+Q9HsfX/  
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} JU6np4  
} S`^W#,rj  
//负责部分文件的抓取 LH8?0N[  
**FileSplitterFetch.java \r2qH0B  
*/ kO#`m]  
package NetFox; =1(BKk>  
_aGdC8%[  
|q>Mw-=  
import java.io.*; i@6 /#  
import java.net.*;
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vP2QAGk<  
SrtmpQ  
public class FileSplitterFetch extends Thread { w\ :b(I  
`iI"rlc  
#+G2ZJxL|  
String sURL; //File URL ba ?k:b  
long nStartPos; //File Snippet Start Position 00p 7sZU^  
long nEndPos; //File Snippet End Position f#t^<`7  
int nThreadID; //Thread's ID mI0r,Z*+M  
boolean bDownOver = false; //Downing is over `lhLIQ'j  
boolean bStop = false; //Stop identical Z^l!y5s/H  
FileAccessI fileAccessI = null; //File Access interface ?Sqm`)\>4  
NZuFxJ-`  
7y\g~?5N  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException a\w|tf  
{ z,)sS<t(  
this.sURL = sURL; 1sjn_fPz  
this.nStartPos = nStart; [ lW "M  
this.nEndPos = nEnd; )8SP$  
nThreadID = id; m+UdT854  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 sdWl5 "  
} u2<h<}Y  
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public void run() q@9i3*q;  
{ l'T0<  
while(nStartPos < nEndPos && !bStop) 8tMt
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{ I={{VQ  
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`1@[uWl  
try{ DeA'D|  
URL url = new URL(sURL); B6\VxSX4{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); PuaosMn(9  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]LTc)[5Zj  
String sProperty = "bytes="+nStartPos+"-"; 836m5/kH[  
httpConnection.setRequestProperty("RANGE",sProperty); % eRwH >  
Utility.log(sProperty); [r8 d+  
17)M.(qmuP  
9 Zm<1Fw  
InputStream input = httpConnection.getInputStream(); U_'q-*W  
//logResponseHead(httpConnection); Mq
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}!V<"d,!  
|:+pPh!-  
byte[] b = new byte[1024]; 8 -;ZPhN&  
int nRead; {Ch"zuPX  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) QV$dKjMS  
{ v6?\65w,|  
nStartPos += fileAccessI.write(b,0,nRead); f+Medc~  
//if(nThreadID == 1) [9om"'  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,
jsx]U/^  
} 7 afA'.=  
YO$b#  
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Utility.log("Thread " + nThreadID + " is over!"); #0^3Wm`X;  
bDownOver = true; sFCs_u1tNN  
//nPos = fileAccessI.write (b,0,nRead); P=[x!}.I  
} |~LjH|*M  
catch(Exception e){e.printStackTrace ();} BON""yIC   
} l=~99m
E  
} 9c}]:3#XO  
AJlIA[Kt:  
)|R0_9CLV  
//打印回应的头信息 e=;@L3f
 
public void logResponseHead(HttpURLConnection con) NvHy'
 
{ {_ho!OS>  
for(int i=1;;i++) N|d.!Q;V.y  
{ W#7-%oT  
String header=con.getHeaderFieldKey(i); JvJ!\6Q@  
if(header!=null) OGi4m |  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); k>;r9^D  
Utility.log(header+" : "+con.getHeaderField(header)); TgE.=`"7  
else ]AA*f_!  
break; )7"DR+;:  
} `)!2E6 =  
} ySK Yqt z  
m *bKy;'8  
P}WhE  
public void splitterStop() t2%@py*bU  
{ X.AWs=:-  
bStop = true; V<NsmC=g  
} lyH X#]  
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vQTQS[
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} 9q)nNX<$)  
\ [^) WQ  
sEJ;t0.LX  
/* t"bPKFRy9E  
**FileAccess.java m57tOX  
*//文件访问(定位，写) yH"$t/cU"R  
package NetFox; K-Dk2(x  
import java.io.*; L!b0y7yR  
`ToRkk&&>{  
+yP[(b/  
public class FileAccessI implements Serializable{ [cLU
*:  
cM<hG:4%wX  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 wI]R+.  
RandomAccessFile oSavedFile; Vh.;p.!e  
long nPos; ;GgQ@s@  
#9hXZr/8  
5IE+
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public FileAccessI() throws IOException zEPx  
{
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this("",0); o +QzQ+ Z  
} WVT5VJ7*  
xlPcg7  
D_19sN@0m  
public FileAccessI(String sName,long nPos) throws IOException J.e8UQ@=5  
{ 9p\wTzA  
oSavedFile = new RandomAccessFile(sName,"rw"); Ubw!/|mi  
this.nPos = nPos; ;LF)u2x=  
oSavedFile.seek(nPos); U3|&Jee  
} 4z0R\tjT  
z^a!C#IX  
& L.PU@  
public synchronized int write(byte[] b,int nStart,int nLen) Nvx)H(8F  
{ kTiPZZI  
int n = -1; X~)V)'R  
try{ wUIsi<Oj  
oSavedFile.write(b,nStart,nLen); (9YYv+GGd*  
n = nLen; ]g8i>,G  
} ll<9f)  
catch(IOException e) A"bSNHCKF  
{ L`HH);Ozw  
e.printStackTrace (); k qY3r &  
} cpF1XpvT  
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%];h|[ax]  
return n; GOZQ5m -  
} X
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.n)!ZN  
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} !}L~@[v,uL  
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/mMAwx  
/* ^ =/?<C4  
**SiteInfoBean.java Hlt8al3  
*/ rt3f7 s*  
package NetFox; \&\_>X.,  
Ha=_u+@  
)O2Nlk~l&  
public class SiteInfoBean { t> x-1vf%  
Uxk[O  
hr_9;,EPh  
private String sSiteURL; //Site's URL
.0Iun+nUD  
private String sFilePath; //Saved File's Path mX<Fuu}E*Z  
private String sFileName; //Saved File's Name $KwI}>E4  
private int nSplitter; //Count of Splited Downloading File B0b[p*gIl  
?u_gXz;A  
m?D <{BQ;  
public SiteInfoBean() wDT>">&d  
{//nSplitter的缺省值为5 {uaZ<4N.  
//default value of nSplitter is 5 MG7 ?N #  
this("","","",5); fr}1_0DDz  
} @)W(q5)}9"  
`2xH7
a-  
%1-K);SJ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) sJ))<,e5I  
{ A9\]3 LY  
sSiteURL= sURL; mQd4#LJ_  
sFilePath = sPath; zb>f;[  
sFileName = sName; ]6$,IKE7  
this.nSplitter = nSpiltter; ?a'6EAErC  
c;:">NR  
Q0zW ]a  
} 7|&e[@B  
]{f^;y8  
CQ6'b,L&   
public String getSSiteURL() G(U9rJ9  
{ :a_BD  
return sSiteURL; '|vD/Qf=&  
} gM4Pj[W  
?PBa'g  
~bdv_|k  
public void setSSiteURL(String value) L'zE<3O'3  
{ BdN8 ^W  
sSiteURL = value; /@ y;iJk;  
} 9T(L"9r-e  
21r== H$  
K)\(wxv  
public String getSFilePath() &
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{ )PR3s1S^  
return sFilePath; xK(IS:HJ*  
} 95=gY  
>T<6fpXuk2  
z{ptm7  
public void setSFilePath(String value) \)ip>{WG  
{ +'%@!  
sFilePath = value; RFw(]o,9cR  
} 3Jk[/.h  
otO j^xU  
*HR+a#o  
public String getSFileName() )2xE z  
{ 8zY)J#  
return sFileName; ^YGTh0$W  
} 5sCFzo<=vh  
6?N4l ]l  
3y99O $EAc  
public void setSFileName(String value) "!O1j r;  
{ )zU:  
sFileName = value; r'/\HWNP  
} `ncNEHh7K  
NUCiY\td  
i}v9ut]B  
public int getNSplitter() IV'p~t
 
{ l3.  
return nSplitter; we3tx{j  
} ow$q7uf  
7h%4]  
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public void setNSplitter(int nCount) 4S|=/f  
{ `H>b5  
nSplitter = nCount; DECB*9O^  
} [#Y' dFQ  
} <:&de8bT  
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R_^/,^1  
/* .h4\{|  
**Utility.java kZLMtj-   
*/ v!9i"@<!  
package NetFox; }g|nz8
  
Ha%F"V*  
c pk^!@c  
public class Utility { 5+- I5HX|~  
i0:>Nk  
6.5wZN9<|  
public Utility() %T!J$a)qf  
{ .m;G$X|3U  
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=wG+Ao  
} d;7uFh|o  
bl;zR  
//线程睡眠 ?<U
{{C  
public static void sleep(int nSecond) vi!YN|}\  
{ @%hCAm  
try{ e)H!uR
 
Thread.sleep(nSecond); 
#aar9  
} \,&9  
catch(Exception e) x[Im%k  
{ D\1k.tI  
e.printStackTrace (); + H_WlYg-  
} @F~LW6K  
} /KCPpERk{  
>9H@|[C  
//日志 p`F9Amb  
public static void log(String sMsg) T6#CK  
{ . ]@=es  
System.err.println(sMsg); X^@I].  
} nV*y`.+  
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 d
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public static void log(int sMsg) LD>\#q8a*  
{ Km#pX1]>e  
System.err.println(sMsg); F_;DN: {  
} ({^9<Us  
}  \ %=9  
"TcW4U9  
TUIk$U?/I  
/* B,WTHU[AV  
**TestMethod.java tK(g-u0N`(  
*/ Y&HK1>M_  
package NetFox; 5O/i3m26  
3+Qxg+<  
@}-r&/#  
public class TestMethod { L!Cz'm"Nl  
)~J>X{hy  
.@q-B+Eg  
public TestMethod() :1ecx$  
{ ///xx/weblogic60b2_win.exe h}`!(K^;3  
try{ H)w(q^i  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xNK1h-t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [,RI-#n  
SiteFileFetch fileFetch = new SiteFileFetch(bean); epHJ@W@#  
fileFetch.start(); H9)m^*  
} YgUH'P-  
catch(Exception e){e.printStackTrace ();} <*!i$(gn  
>LC<O.  
tR0pH8?e"  
} wxg^Bq)D*R  
<h).fX  
l>gI&1)%  
public static void main(String[] args) s=6}%%q6  
{ b-U eIjX  
new TestMethod(); IQ<MyB(  
} 9^"b*&>P  
}
}?F`t[+  
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