http断点续传简单实现（java)

/* 5gc:Y`7t  
**SiteFileFetch.java 2yJ7]+Jd7Y  
*/ KtfkE\KP  
package NetFox; q-3J.VLJ5H  
import java.io.*; G {pP}  
import java.net.*; dEQReD  
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public class SiteFileFetch extends Thread { !X\sQNp  
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SiteInfoBean siteInfoBean = null; //文件信息Bean k5fH;  
long[] nStartPos; //开始位置  '{j
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long[] nEndPos; //结束位置 ui.QYAYaV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 p-T~x$"c|  
long nFileLength; //文件长度 m0BG9~p|  
boolean bFirst = true; //是否第一次取文件 %/tGkS6  
boolean bStop = false; //停止标志 U5On-T5  
File tmpFile; //文件下载的临时信息 =0PNHO\gl  
DataOutputStream output; //输出到文件的输出流 9{9#AI.G  
}j5R@I6P  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [.#p  
public SiteFileFetch(SiteInfoBean bean) throws IOException f gK2.;>  
{ {p#l!P
/  
siteInfoBean = bean; T.R>xd`9 "  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); taWirqd9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8"?Vcw&  
if(tmpFile.exists ()) SgCqxFii  
{ m0%iw1OsH%  
bFirst = false; /^z/]!JG:V  
read_nPos();
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} )T.pjl  
else VeNNsg>&  
{ Y'<uZl^aX  
nStartPos = new long[bean.getNSplitter()]; B c,"12  
nEndPos = new long[bean.getNSplitter()]; fw1;i  
} +?"HTDBE||  
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} (1kn):  
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public void run() AQnJxIL:  
{ ~J:$gu~`  
//获得文件长度 {dy` %It  
//分割文件 2_oK5*j  
//实例FileSplitterFetch Njy9JX  
//启动FileSplitterFetch线程 d{iu+=NXz  
//等待子线程返回 7~!I2DV_  
try{ 9D{u,Q V  
if(bFirst) l#2r.q^$|  
{ CU#L *kz  
nFileLength = getFileSize(); eHVdZ'%x  
if(nFileLength == -1) r!=]Q}`F  
{ ;1{iF2jZ:  
System.err.println("File Length is not known!"); D+ah ok  
} "fX_gN?  
else if(nFileLength == -2) S4l)TtY  
{ WX%h4)z*  
System.err.println("File is not access!"); .iOw0z  
} p<of<YU)  
else %gV)arwK  
{ c*S#UD+  
for(int i=0;i<nStartPos.length;i++) 5}-)vsa`  
{ 4B:\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &57qjA,8<  
} ]6a/0rg:t  
for(int i=0;i<nEndPos.length-1;i++) ^G|w8t+^  
{ vO}qjw  
nEndPos = nStartPos[i+1]; |uQn|"U4  
} =,&u_>Dp  
nEndPos[nEndPos.length-1] = nFileLength; G]L0eV  
} ^#a#<8Jz  
} VR
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?dp-}3/G  
%-h7Z3YcN  
//启动子线程 ~u_K&X  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 17V\2=Io  
for(int i=0;i<nStartPos.length;i++) c^
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{ !pd7@FwC  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x><zGXvvp|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bajC-5R1k  
nStartPos,nEndPos,i); uuI3NAi~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kN'|,eKH4  
fileSplitterFetch.start(); w;N{>)hv  
} Tjd&^m  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [=XZza.z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); v;)BVv  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <ldid]o #  
nEndPos = " + nFileLength); t!6\7Vm/  
// fileSplitterFetch[nPos.length-1].start(); gzl%5`DBw  
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ox(*  
//等待子线程结束 sl~b\j  
//int count = 0; WafdE  
//是否结束while循环 Q;XXgX#l  
boolean breakWhile = false; fl!mYCPv  
{M`  
L\QQjI{  
while(!bStop) 3M}AxEu  
{ %3]3r*e&5  
write_nPos(); 21.YO]Et  
Utility.sleep(500); ::4"wU3t  
breakWhile = true; K&j'c  
+V2C}NQ5R  
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for(int i=0;i<nStartPos.length;i++) {@Blj3;w}  
{ X }m7@r@  
if(!fileSplitterFetch.bDownOver) 1t0bUf;(M  
{ 5|yZEwq  
breakWhile = false; !Bag}|#  
break; q:xtm?'$  
} y.jS{r".  
} QH& %mr.S  
if(breakWhile) aF D="Zh  
break; x2sN\tOh^  
s ;48v  
2;&mkcK'  
//count++; ?+3R^%`V  
//if(count>4) \U==f&G?J  
// siteStop();  =Ov9Kf  
} 0v;ve  
;])I>BT[  
$`E4m8fX  
System.err.println("文件下载结束！"); uEBQo
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} YavfjS:2  
catch(Exception e){e.printStackTrace ();} K3La9O)>  
} q A.+U:I8  
|c<XSX?ir  
jjxIS  
//获得文件长度 RI?NB6U  
public long getFileSize() w#W5}i&x  
{ *hV4[=  
int nFileLength = -1; OMl8 a B9  
try{
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URL url = new URL(siteInfoBean.getSSiteURL()); LOe4c0C6Ca  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q?Wr7  
httpConnection.setRequestProperty("User-Agent","NetFox"); N0]z/}hd@  
baqn7k"  
O ,l\e3;  
int responseCode=httpConnection.getResponseCode(); C=8H)Ef,l  
if(responseCode>=400) )sqaR^  
{ ',DeP>'%>  
processErrorCode(responseCode);
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return -2; //-2 represent access is error OE6#
YT  
} JAN|a
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=1O?jrl~q  
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String sHeader; ;D:=XA%  
*`%4loW  
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for(int i=1;;i++) ?%93b ,7  
{ q{/*n]K  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "=FIFf  
//Utility.log(in.readLine()); g/x_m.  
sHeader=httpConnection.getHeaderFieldKey(i); *JwFD^<j  
if(sHeader!=null) AYt*'Zeg!s  
{ [@g~  
if(sHeader.equals("Content-Length")) &
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{ ZH% we  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); hUBF/4s\  
break; (Bsw/wv  
} ,b$z!dvhl  
} UBa-  
else l4zw]AYk+X  
break; 5|5=Y/  
} ad9EG#mD#  
} f:S}h-AL&  
catch(IOException e){e.printStackTrace ();} A3j"/eKi2  
catch(Exception e){e.printStackTrace ();} )x)gHY8;  
% ^e@`0L  
3<+z46`?  
Utility.log(nFileLength); a`s/qi  
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return nFileLength; 8'+7i8e  
} Xt\Dy  
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//保存下载信息（文件指针位置） Zct!/u9 Q  
private void write_nPos() z1#o
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{ ,^HS`!s[ E  
try{ f*v1J<1#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {|Bd?U;  
output.writeInt(nStartPos.length); \,hrk~4U;(  
for(int i=0;i<nStartPos.length;i++) l`*( f9Q  
{ 4Q$!c{Y r  
// output.writeLong(nPos); 2!BsEvB(  
output.writeLong(fileSplitterFetch.nStartPos); 6oYIQ'hc  
output.writeLong(fileSplitterFetch.nEndPos); uQWp+}>ZJy  
} 4AuH1m)<  
output.close(); Ohi D  
} +3)[>{~1Z  
catch(IOException e){e.printStackTrace ();} i]dz}=j'  
catch(Exception e){e.printStackTrace ();} IEc>.J|T&  
} BK*z 4m  
m
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//读取保存的下载信息（文件指针位置） 1c/ X  
private void read_nPos() p+vh[+yp  
{ C>NQ-w^  
try{ RNvQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); D@:"f?K>  
int nCount = input.readInt(); j!7Qw 8  
nStartPos = new long[nCount]; ZRPE-l_3:  
nEndPos = new long[nCount]; my4\mi6P  
for(int i=0;i<nStartPos.length;i++) $3]b>v  
{ tGC2 ^a#~  
nStartPos = input.readLong(); brfKd]i  
nEndPos = input.readLong(); Ms,@t^nk  
} ETe-  
input.close(); "U*5Z:8?9  
} YroNpu]s  
catch(IOException e){e.printStackTrace ();} I ld7}R
 
catch(Exception e){e.printStackTrace ();} g1ytT%]  
} ,&[7u9@  
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private void processErrorCode(int nErrorCode) *Er? C;  
{ (2d3jQN`  
System.err.println("Error Code : " + nErrorCode); Hxn<(gd G  
} J$rJd9t  
W~<m[#:6C  
<>n9'i1  
//停止文件下载 qrpb[)Ll  
public void siteStop() \1]rlzXGUT  
{ KI`11lJW~  
bStop = true; >IBTBh_ka  
for(int i=0;i<nStartPos.length;i++) "9%qbMB  
fileSplitterFetch.splitterStop(); UP]1(S?  
"1K:/n  
#cO+<1  
} Hv8H.^D>  
} LJj=]_  
//负责部分文件的抓取 ydB$4ZB3[  
**FileSplitterFetch.java )d:K:YXt  
*/ zA,/@/'(  
package NetFox; s%^o*LQ|9  
(![t_r
0  
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import java.io.*; o)p[ C   
import java.net.*; dl_{iMhF&E  
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public class FileSplitterFetch extends Thread { /LF3O~Go  
C 0>=x{,v  
fx]eDA|$e  
String sURL; //File URL
nc&Jmo7  
long nStartPos; //File Snippet Start Position HA1]M`&  
long nEndPos; //File Snippet End Position -zTEL(r  
int nThreadID; //Thread's ID BJgDo  
boolean bDownOver = false; //Downing is over E23w *']  
boolean bStop = false; //Stop identical NHAH#7]M&1  
FileAccessI fileAccessI = null; //File Access interface {\L|s5=yr  
@C=M UT-!  
9qre|AA  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v&r=-}z2!  
{ u1N1n;#  
this.sURL = sURL;
06jMj26!  
this.nStartPos = nStart; GQ[pG{_+  
this.nEndPos = nEnd; uOre,AQR  
nThreadID = id; ikIzhUWE  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /BT1oWi1y  
} =U c$D*  
-;U3w.-  
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public void run() gB >pd?d  
{ YmgCl!r@  
while(nStartPos < nEndPos && !bStop) ;iQ
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{ 9x[ U$B  
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try{ {>h97}P  
URL url = new URL(sURL); 2uL9.q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c.0]1  
httpConnection.setRequestProperty("User-Agent","NetFox"); / gu3@@h  
String sProperty = "bytes="+nStartPos+"-"; !UcOl0"6  
httpConnection.setRequestProperty("RANGE",sProperty); kW
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Utility.log(sProperty); ).Gd1pE  
:3 y_mf>  
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InputStream input = httpConnection.getInputStream(); [
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//logResponseHead(httpConnection); "wINBya'M  
q#'VJA:A5&  
p[-
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byte[] b = new byte[1024]; `m, Ki69.  
int nRead; N+J>7_k   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) s/h7G}Mu  
{ ul=7>";=|  
nStartPos += fileAccessI.write(b,0,nRead); M~p=#V1D  
//if(nThreadID == 1) (Q_2ODKo  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r)8z#W>s  
} sf)W~Lx5a  
:".w{0l@  
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Utility.log("Thread " + nThreadID + " is over!"); c D7FfJ  
bDownOver = true; d;44;*D  
//nPos = fileAccessI.write (b,0,nRead); a:b^!H>#  
} :<%vE!$  
catch(Exception e){e.printStackTrace ();} @)b^^Fp  
} ;(S|cm'>}  
} r.<
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K}K)`bifw  
UJn/s;$.e  
//打印回应的头信息 8gI\zgS  
public void logResponseHead(HttpURLConnection con) 5(#-)rlGj  
{ VMF|iB  
for(int i=1;;i++) t%$@fjz
 
{ o\goE^,aeR  
String header=con.getHeaderFieldKey(i); 8(Fu  
if(header!=null) f'_M0x  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); L=g_@b  
Utility.log(header+" : "+con.getHeaderField(header)); ^/a*.cu  
else m|1n x  
break; 2yxi= XWZ  
} VDpxk$a  
} DEtf(lW_  
{cR3.%wX  
B6%&gXr\  
public void splitterStop() w~LU\Ct  
{ @ae
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bStop = true; >{t+4p4k.  
} l"5y?jT  
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(3W&AM  
} x5F@ad9  
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/* D:m#d.m  
**FileAccess.java 'HB~Dbq`V  
*//文件访问(定位，写) /[?Jylj  
package NetFox; &O*ENpF  
import java.io.*;
d1bhJK  
w+=Q6]FxJ  
km4g}~N</  
public class FileAccessI implements Serializable{ <+q$XL0  
enumK\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |^iA6)Q  
RandomAccessFile oSavedFile; y\z > /q  
long nPos; 6#|qg*OS  
41}/w3Z4  
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public FileAccessI() throws IOException ls @5^g  
{ Ay%:@j(E  
this("",0);
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}  Q;20T  
+'%\Pr(  
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public FileAccessI(String sName,long nPos) throws IOException (Fqa][0  
{ }# Xi`<{  
oSavedFile = new RandomAccessFile(sName,"rw"); S_5?U2%D  
this.nPos = nPos; b{pg!/N4  
oSavedFile.seek(nPos); Hg whe=P  
} jb3.W  
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L|J~9FM  
public synchronized int write(byte[] b,int nStart,int nLen) F`srE6H  
{ EneAX&SG  
int n = -1; q,@+^aZ  
try{ @\PpA9ebg%  
oSavedFile.write(b,nStart,nLen);  qpTm  
n = nLen; ` FxtLG,F  
} U`1l8'W}:#  
catch(IOException e) 4+Ti7p06&\  
{ blp=Hk  
e.printStackTrace (); BKZ v9  
} ,R~eY?{a  
.YC;zn^  
VA2<r(y~(  
return n; ,CKvTxz0  
} 1i+FL''  
r--;yEjWE  
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} ugxw!cj  
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!  
/RqhykgZ  
/* l
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**SiteInfoBean.java HlRAD|]\  
*/ oLP]N$'#  
package NetFox; ppFYc\&=  
n ,1tD  
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public class SiteInfoBean { #TATqzA  
+c r  
6w!e?B2/%  
private String sSiteURL; //Site's URL L=m:/qQL  
private String sFilePath; //Saved File's Path !7c'<[+Hm  
private String sFileName; //Saved File's Name |[ocyUsxX  
private int nSplitter; //Count of Splited Downloading File b^Z$hnh]S  
u G[!w!e  
P&\X`ZUA  
public SiteInfoBean() tN}
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{//nSplitter的缺省值为5 Cya5*U0=  
//default value of nSplitter is 5 3Ta>Ki  
this("","","",5); HEpM4xe$  
} 8Z!*[c>K-?  
+f|6AeE  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *]2R.u  
{ C fSl 54  
sSiteURL= sURL; n}:t<  
sFilePath = sPath; AsAFUuI  
sFileName = sName; n.Vtc-yZU  
this.nSplitter = nSpiltter; u}m.}Mws  
:MBS>owR  
>b43%^yii  
} F"=Hp4-C  
!&JiNn('  
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public String getSSiteURL() {U6"]f%  
{ M8zE3;5  
return sSiteURL; gD1+]am  
} cUsL6y  
8T7f[?  
Gh=<0WaF=  
public void setSSiteURL(String value) ?} X}#  
{ kXEtuO5FUM  
sSiteURL = value; Of#K:`1@  
} esteFLm`6  
[-]A^?yBM  
_25d%Ne0  
public String getSFilePath() pI5_Hg  
{ hb<k]-'!  
return sFilePath; Pxk0(oBX  
} *`1bc'umM;  
S\b K+  
niQcvnT4b  
public void setSFilePath(String value) *;P2+cE>H3  
{ /.2qWQH  
sFilePath = value; 9fMSAB+c%  
} .?Auh2nr  
.<dOED{v  
/sV?JV[t  
public String getSFileName() @`Wt4<  
{ 6W:1>,xS  
return sFileName; #!L%J<MX  
} fa yKM  
#Z!#;%S  
U$%|0@`~  
public void setSFileName(String value) AI~9m-,mE  
{ >fg4x+0%  
sFileName = value; tO`?{?W7  
} i7(~>6@|  
sxk*$jO[]  
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public int getNSplitter() yYk|YX(7U  
{ ;.AV;C"  
return nSplitter; wsI5F&R,  
}
?CFoe$M  
tJz^DXqAc  
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public void setNSplitter(int nCount) ]K*GSU  
{ }b
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nSplitter = nCount; MISE C[/  
} @sdS0pC  
} 19) !$Hl  
%}ixgs7*c0  
V pH|R  
/* *k4+ioFnKE  
**Utility.java L W?&a3e  
*/ A9iQ{l  
package NetFox; _{mJ.1)V;  
~hzEKvs  
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public class Utility { ]xYayN!n  
#?Wo <]i  
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public Utility() W.p66IQwL&  
{ U&s(1~e\  
pW7kj&a_.  
G\):2Qz!|  
} (Wn "3 ]  
l<Lz{)OR  
//线程睡眠 ?l>e75V%w  
public static void sleep(int nSecond) Y!aLf[x]  
{ 7g8B'ex J  
try{ &#Wkww&Y  
Thread.sleep(nSecond); Bqp&2zg)@  
} w0X$rl1  
catch(Exception e) >R#9\/s  
{ Stt* 1gT  
e.printStackTrace (); MorW\7-}  
} }`#B
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} t+J)dr  
zG<0CZQ8  
//日志 "!^c  
public static void log(String sMsg) 'cYQ?;  
{ ze ?CoDx2  
System.err.println(sMsg); tbY SK  
} =:
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HI z9s4Y_  
public static void log(int sMsg) $CM4&{B"i  
{ J7_8
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System.err.println(sMsg); c9|I4=_K  
} O8iu+}]/6  
} XA?WUR[e  
`k!UjO72  
sC9-+}  
/* We|-5  
**TestMethod.java F-$Kv-f  
*/ uO6c3|Zjs  
package NetFox; ;*_I,|A:Xr  
9wzg{4/-$  
V54q"kP,@.  
public class TestMethod { tG_-;03<`4  
2=Jmi?k  
B JU*`Tx  
public TestMethod() 9Y\F53p&j  
{ ///xx/weblogic60b2_win.exe aam1tm#Q  
try{ -}NAb^d  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0:s8o@}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); g:;Ya?5N  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !\3}R25  
fileFetch.start(); Qf"6PJ  
} s!NisF  
catch(Exception e){e.printStackTrace ();} `I@)<d  
{rs6"X^  
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} )ynA:LXx  
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public static void main(String[] args) t;oT {Hge  
{ )Gx": D  
new TestMethod(); 2n _T2{  
} @ca#U-:g  
} W6)dUi :"  
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