http断点续传简单实现（java)

/* ``o:N`  
**SiteFileFetch.java yi3@-
 
*/ 6KmF 9  
package NetFox; K;2tY+I  
import java.io.*; |5SYKA7CS  
import java.net.*; RaFk/mSw  
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public class SiteFileFetch extends Thread { _p vL b  
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SiteInfoBean siteInfoBean = null; //文件信息Bean &$fe%1#  
long[] nStartPos; //开始位置 F"9f6<ge  
long[] nEndPos; //结束位置 )J+vmY~&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 SGMLs'D   
long nFileLength; //文件长度 5gWn{[[e)y  
boolean bFirst = true; //是否第一次取文件 =:(8F*Q  
boolean bStop = false; //停止标志 4NxtU/5-sU  
File tmpFile; //文件下载的临时信息 @p jah(i`  
DataOutputStream output; //输出到文件的输出流 5H#3PZaQ
 
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Y
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public SiteFileFetch(SiteInfoBean bean) throws IOException eRllF`*  
{ ,R$n I*mf_  
siteInfoBean = bean; F|X-|Co  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >l
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v/f&rK*>  
if(tmpFile.exists ()) d[z+/L  
{ z#b31;A@$  
bFirst = false; _Tyj4t0ElV  
read_nPos(); 6C>x,kU  
} 6o&{~SV3  
else a3]'%kKp  
{ 9PEjV$0E2  
nStartPos = new long[bean.getNSplitter()]; krm&.J  
nEndPos = new long[bean.getNSplitter()]; Ow=`tv$l  
} )K\w0sjR  
[Dp6q~RM  
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} -nG3(n&wB  
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public void run() R,01.N( U  
{ z%t>z9hU  
//获得文件长度 +u*WUw!%  
//分割文件 bU1UNm`{C  
//实例FileSplitterFetch kEWC  
//启动FileSplitterFetch线程 xmZ]mu,,$  
//等待子线程返回 e-f_#!bW  
try{ Gk2\B]
{  
if(bFirst) $@q)IK%FDL  
{
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nFileLength = getFileSize(); RL
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if(nFileLength == -1) :h1itn  
{ E,5jY  
System.err.println("File Length is not known!"); Y+ P\5G  
} r: n^U#  
else if(nFileLength == -2) >:5/V0;,  
{ !<}<HR^)  
System.err.println("File is not access!"); S|
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} j2"jCv  
else %VsuGA  
{ <pRb#G"  
for(int i=0;i<nStartPos.length;i++) >1xlP/4jx  
{ he&*N*of:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); M~;Ww-./  
} LOi5 ^Um|  
for(int i=0;i<nEndPos.length-1;i++) pm O}m>  
{ +](^gaDw<L  
nEndPos = nStartPos[i+1]; IZe
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} o
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nEndPos[nEndPos.length-1] = nFileLength; N5[QQtQ  
} g+p?J.+  
} 1p>5ZkHb  
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Uce
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//启动子线程 XX~~SvSM  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Lm"l*j4  
for(int i=0;i<nStartPos.length;i++) |eWlB\ x8  
{ e.n&Os<|<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]~CGzV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @v_ )(  
nStartPos,nEndPos,i); draY/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?AX./LI  
fileSplitterFetch.start(); u\-xlp?"o  
} $Ne$s
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8vK Z;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); gO4`e(W  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Z1u{.^~^z  
nEndPos = " + nFileLength); 8$-(%  
// fileSplitterFetch[nPos.length-1].start(); 828E^Q"<  
8.Wf^j$+{  
YmFJlMK  
//等待子线程结束 c&IIqT@Gb0  
//int count = 0; >V@-tT"^:  
//是否结束while循环 _kl.zw%  
boolean breakWhile = false; [Hy0j*  
u!?.vx<
qy  
xl@l<  
while(!bStop) ,*8}TIS(s  
{ yb56nd  
write_nPos(); M?x/C2|  
Utility.sleep(500); |2AK~t|t  
breakWhile = true; jTaEaX8+  
i}N'WV`!  
` *x;&.&v  
for(int i=0;i<nStartPos.length;i++) I/rq@27o  
{ !.H< dQS  
if(!fileSplitterFetch.bDownOver) $0V<wsVM  
{ O8TAc]B  
breakWhile = false; =K~<& l8
 
break; BZ<Q.:)  
} Y~hBVz2g  
} X0+$pJ60  
if(breakWhile) w0x,~  
break; /`>BPQH`}  
<H`&Zqqk  
J7/"8S_#N  
//count++; 1om:SHw  
//if(count>4) +'Pf|S  
// siteStop(); p]:5S_$  
} ihBlP\C  
i&$L$zf,  
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System.err.println("文件下载结束！"); %f
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} 6%~ Z^>`N  
catch(Exception e){e.printStackTrace ();} q3TAWNzI0  
} 3qE2mYK  
M%5qx,JQY  
nAG2!2_8  
//获得文件长度 u;H SX  
public long getFileSize() Eb{Zm<TP  
{ Tn< <i  
int nFileLength = -1; %WiDz0o  
try{ 5Jh=${  
URL url = new URL(siteInfoBean.getSSiteURL()); ='a[(C&Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @v\Osp t=  
httpConnection.setRequestProperty("User-Agent","NetFox"); `WGT`A"  
thIuK V{CO  
pca `nN!  
int responseCode=httpConnection.getResponseCode(); <43O,Kx'Su  
if(responseCode>=400) "VR>nyG%  
{ .z4 fJx  
processErrorCode(responseCode); =<MSM\Rb  
return -2; //-2 represent access is error r) ;U zd  
} <R582$( I  
{Y6U%HG{{r  
WM$}1:O
 
String sHeader; c+,F)i^`  
ozwPtF5  
nh"nSBRxk  
for(int i=1;;i++) UUJbF$@;  
{ Q^>"AhOiU  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); / CEnyE/  
//Utility.log(in.readLine()); X*hY?'Rp  
sHeader=httpConnection.getHeaderFieldKey(i);
YAQ]2<H  
if(sHeader!=null) yaza  
{ A-x; ai]  
if(sHeader.equals("Content-Length")) $OB2ZS"  
{ / E}L%OvE  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +XCLdf}dC  
break; d*$$E  
} jcD_<WSe  
} #N9^C@  
else k#X~+}N^  
break; f]Z%,'1^  
} n4\UoKq  
} L"{qF<@V7&  
catch(IOException e){e.printStackTrace ();} 4v9jGwnzt  
catch(Exception e){e.printStackTrace ();} kk#%x#L[  
Cl#PYB{1Y  
X)^eaw]Q0  
Utility.log(nFileLength); 9"hH2jc  

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return nFileLength; Yci>'$tQ  
} 'Dw+k;RH  
F|pM$Kd`  
2*;qr|h,  
//保存下载信息（文件指针位置） Yw @)0%G  
private void write_nPos() qg1s]c~0u  
{ 9'+Eu)l:  
try{ "g27|e?y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); zGgPW  
output.writeInt(nStartPos.length); z,dh?%H>X  
for(int i=0;i<nStartPos.length;i++) hS&3D6Gt  
{ !*Ex}K99  
// output.writeLong(nPos); E| eEAa  
output.writeLong(fileSplitterFetch.nStartPos); ZD!?mR+-  
output.writeLong(fileSplitterFetch.nEndPos); %PA#x36
 
} mbT4K8<^  
output.close(); XzLB#0  
} &?X0;,5)  
catch(IOException e){e.printStackTrace ();} X<G"GaL  
catch(Exception e){e.printStackTrace ();} `|kW%L4  
} ?-M?{De  
)1?#q[x  
ls[0X82F
 
//读取保存的下载信息（文件指针位置） 3 UUOB.  
private void read_nPos() (Yi1U~{:  
{ En!X}Owh  
try{ }@6Tcn1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); D!7-(3R  
int nCount = input.readInt(); 6[+@#IWx  
nStartPos = new long[nCount]; @7S* ]  
nEndPos = new long[nCount]; qFQO1"mu  
for(int i=0;i<nStartPos.length;i++)
bmCp:
6  
{ m8[XA!,  
nStartPos = input.readLong(); xf2|9Tqt  
nEndPos = input.readLong(); FgwIOpqE*  
} yuP1*QJ%  
input.close(); 1N\/61+aA  
} l9{}nz  
catch(IOException e){e.printStackTrace ();} P=3mLz-  
catch(Exception e){e.printStackTrace ();}  T.d1?  
} $?P5A E  
ZZ'5BfI"I%  
lo!^h]iE!  
private void processErrorCode(int nErrorCode) +G:CR,Z>+  
{ 6_mkt|E=  
System.err.println("Error Code : " + nErrorCode); (8"advc6  
} _(7f0p  
jxc^OsYj  
_:+hB9n s  
//停止文件下载 p~Wy`g-  
public void siteStop()  'ug:ic  
{ W kP`qD3  
bStop = true; L2\<iJA}c  
for(int i=0;i<nStartPos.length;i++) +H{TV#+r  
fileSplitterFetch.splitterStop(); q4MR9ig1E_  
{,NF'x4$  
[?>\]  
} &&PXWR!%]  
} lcVZ 32MQ  
//负责部分文件的抓取 uH{oJSrK  
**FileSplitterFetch.java %eOO8^N  
*/ n2A ; `=  
package NetFox; k\76`!B  
}G/!9Zq  
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import java.io.*; <aQ<Wy=\  
import java.net.*; B\54eTn  
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?3 S{>+'  
public class FileSplitterFetch extends Thread { )4#YS$B$@)  
)JrG`CvdU  
q
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String sURL; //File URL \s?8}k  
long nStartPos; //File Snippet Start Position U9"(jl/o  
long nEndPos; //File Snippet End Position 9Bao~(j/k  
int nThreadID; //Thread's ID WQ+ xS!ba  
boolean bDownOver = false; //Downing is over  CK+t6Gp  
boolean bStop = false; //Stop identical xlcL;
e&^P  
FileAccessI fileAccessI = null; //File Access interface x^zw1e,y  
;\g0*b(  
"5HSCl$r%  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException oRZ98?Y\B  
{ "wy2u~  
this.sURL = sURL; j:2TicHDC  
this.nStartPos = nStart; s_;o1 K0  
this.nEndPos = nEnd; j-cp  
nThreadID = id; 5,R4:y ?cK  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?}e^-//*i  
} Kn=0AdM  
w,i?e\5  

=&i#NSK  
public void run() i!{A7mo  
{ s(T0lul  
while(nStartPos < nEndPos && !bStop) !,|-{":  
{ 
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try{ P$x9Z3d_  
URL url = new URL(sURL); Jmuyd\?,b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h% eGtd$n  
httpConnection.setRequestProperty("User-Agent","NetFox"); I&U.5wf  
String sProperty = "bytes="+nStartPos+"-"; @<.ei)
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httpConnection.setRequestProperty("RANGE",sProperty); L} "bp  
Utility.log(sProperty); u69UUkG  
{/j gB"9  
R<B5<!+  
InputStream input = httpConnection.getInputStream(); esiU._:u  
//logResponseHead(httpConnection); D0Mxl?S?  
&,P; 7R  
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byte[] b = new byte[1024]; k Nvb>v  
int nRead; bcq&y
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 7YxVtN  
{ 8_VGB0~3i  
nStartPos += fileAccessI.write(b,0,nRead); '&+]85_&$  
//if(nThreadID == 1) x2sKj"2?@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5T%2al,F`  
} !w}b}+]GB  
;W T<]  
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Utility.log("Thread " + nThreadID + " is over!"); ;F|#m,2Q-  
bDownOver = true; riL|B3  
//nPos = fileAccessI.write (b,0,nRead); KL6B!B{;  
} 2!6E~<
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catch(Exception e){e.printStackTrace ();} d>?C?F  
} HSWki';G  
} Er;qs*f  
NLr
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^Ze(WE)  
//打印回应的头信息 &~Y%0&F,&  
public void logResponseHead(HttpURLConnection con) qm"SN<2S*  
{ ;mYZ@g%e  
for(int i=1;;i++) \%&A? D  
{ 0 *;i]owV  
String header=con.getHeaderFieldKey(i); {cUGksz]}  
if(header!=null) oI!"F=?&6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *u-$$@|y  
Utility.log(header+" : "+con.getHeaderField(header)); h\p!J-V  
else E~#G_opQA  
break; dl"=ZI '^  
} 0hhxTOp  
} Rc:}%a%e  
>|z:CX$]  
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public void splitterStop() :tbgX;tCs5  
{ 5S8>y7knQ  
bStop = true; H~TuQ  
} L2p?]:-  
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oNIYO*[  
} < =~=IZ)  
2WDe34   
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/* S]ayH$w\Q  
**FileAccess.java G pI4QzR  
*//文件访问(定位，写) cxQAp  
package NetFox; B~^*@5#0|  
import java.io.*; /{:XYeX  
L}CU"  
"-djA,`  
public class FileAccessI implements Serializable{ Pro?xY$E)  
<5D4h!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 5'NNwc\  
RandomAccessFile oSavedFile; 1)^\R(l  
long nPos; }LCm_av  
<T?-A}0uO  
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public FileAccessI() throws IOException !(7m/R  
{ P JATRJ1.  
this("",0); _7\`xU  
} Y<|JhqOXK  
cE:s\hG  
p3Qls*  
public FileAccessI(String sName,long nPos) throws IOException z bYv}q  
{ Yb^e7Eug  
oSavedFile = new RandomAccessFile(sName,"rw"); `kuu}YUi  
this.nPos = nPos; p:TE##
  
oSavedFile.seek(nPos); }ymW};W  
} ^utOVi  
=3c?W&:  
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public synchronized int write(byte[] b,int nStart,int nLen) Dm{Xd+Y  
{ o5p{ O>D[z  
int n = -1; G"` }"T0}  
try{ -Uy)=]Zae  
oSavedFile.write(b,nStart,nLen); R;!@ xy  
n = nLen; \HbZ~I-  
} U+qyS|i  
catch(IOException e) "d:rPJT)(@  
{ W03mdRW  
e.printStackTrace (); 1$eoW/8.  
} F$DA/{.D  
4VZI]3K,  
,+ G  
return n; Nd]F 33|X  
} g3c<c S^l  
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} triU^uvh
 
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/* cFw-JM<  
**SiteInfoBean.java SFRP ?s  
*/ ,\J 8(,%L  
package NetFox; <wk  
!DzeJWM|  
#<< el;n  
public class SiteInfoBean { L&DjNu`!9  
Sc]K-]1(H  
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private String sSiteURL; //Site's URL F$)l8}  
private String sFilePath; //Saved File's Path 2PYnzAsl  
private String sFileName; //Saved File's Name ;O% H]oN  
private int nSplitter; //Count of Splited Downloading File 5PO_qr=Hx  
JyZuj>` 6  
o *J*}y  
public SiteInfoBean() #Z1-+X8P  
{//nSplitter的缺省值为5 mA{?E9W  
//default value of nSplitter is 5 udqrHR5  
this("","","",5); TG}owG]]  
} ":$4/b6  
s-#EV  
c 9f"5~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) r@3-vLI!u  
{ U}5fjY  
sSiteURL= sURL; =}#yi<Lt  
sFilePath = sPath; 6&os`!  
sFileName = sName; {lWVH  
this.nSplitter = nSpiltter; m;~}}~&vQ  
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vSR&>Q%X  
} ;:D-}t;  
;.uYWP|9  
#+1|O;PB#  
public String getSSiteURL() -n.m "O3  
{ yuZLsH  
return sSiteURL; u-t=M]  
} -}%J3j|R:  
J)YlG*  
FL'}~il  
public void setSSiteURL(String value) 9$\s v5  
{ g8N"-j&@  
sSiteURL = value; ksC_F8Q+  
} aO(PVS|P  
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xT"V9t[f  
public String getSFilePath() QCW4gIp  
{ 9>&zOITTaL  
return sFilePath; bI &<L O  
} @4*:qj?  
0~fjY^(  
/eQAGFG  
public void setSFilePath(String value) #"4ioTL2  
{ -5b|nQuY  
sFilePath = value; =@Oo3*>  
} \:4*h  
_li3cXE  
'h
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public String getSFileName() h.X4x2(.  
{ Jj\4P1|'7  
return sFileName; 9(^UchZZi  
} 8X7??f1;Y  
-x+3nb|.  
G$>?UQ[  
public void setSFileName(String value) ekhv.;N~  
{ 3:x(2 A  
sFileName = value; A0Mjk  
} X(
ph
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tLy:F*1i  
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public int getNSplitter() @q
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{ /xk7Z q  
return nSplitter; pJ] Ix *M  
} 0(7 IsG=t  
>}V?GK36  
tVRN3fJH  
public void setNSplitter(int nCount) `3F#k[IR  
{ /Sj~lHh  
nSplitter = nCount; +]%S}<R  
} zL yI|%KH  
} )$n%4 :  
/A7( `l;6  
r!Aj5  
/* ~</FF'Xz  
**Utility.java !1)aie+p6  
*/ zl1*GVg  
package NetFox; Xfc$M(a K{  
(L/>LZn|  
&'z_:Wm  
public class Utility { UTkPA2x  
Q~U\f$N  
j?2~6W/[  
public Utility() ({!!b"B2  
{ ""-wM~^D  
}YDi/b7  
5tlRrf  
} 1tNL)x"w  
%
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//线程睡眠 }Ja-0v)Wf  
public static void sleep(int nSecond) 4`,(*igEv  
{ R
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try{ (A~7>\r +  
Thread.sleep(nSecond); 0#]fEi  
} Bg~]
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catch(Exception e) z
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{ dVb6u  
e.printStackTrace (); OMLU ;,4  
} ^>IP"kF  
} {fXkbMO|  
Nj>6TD81u  
//日志 (TT=i  
public static void log(String sMsg) 6|jZv~rS$  
{ aRMlE*yW  
System.err.println(sMsg); ~n]5iGz  
} _@ao$)q{J  
*?X&Y8Kf  
u<S`"MR:J  
public static void log(int sMsg) #%E`~&[  
{ *E/Bfp1LIe  
System.err.println(sMsg); [9"
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} #kC~qux^  
} yvB]rz} i  
_N`.1Dl%Q  
4zMvHe  
/* [bh?p+V  
**TestMethod.java c[Fc
3  
*/ _KH91$iW8m  
package NetFox; ,R{&x7  
Sb`[+i'`  
X"{%,]sb G  
public class TestMethod { ;"MChk  
+dCDk* /m  
0/Q_% :  
public TestMethod() \jC
) ;mk  
{ ///xx/weblogic60b2_win.exe 9lYKG^#D  
try{ {W,5]-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); xk,Uf,,>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); At.&$ t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v?`R8  
fileFetch.start(); T~]~'+<Pi  
} {xTq5`&gT  
catch(Exception e){e.printStackTrace ();} l?m"o-Gp3  
o[!'JUxZ  
geG0F}oC!  
} wsQnjT>
 
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public static void main(String[] args) X?_rD'3  
{ Vh\_Ko\V5  
new TestMethod(); }QI \K  
} R{@saa5I(>  
} UdO8KD#r3  
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