http断点续传简单实现（java)

/* JqQ3C}z  
**SiteFileFetch.java C~:b*X  
*/ zQ=aey%  
package NetFox; t3K>\ :  
import java.io.*; Zr5'TZ`$  
import java.net.*; O${r^6Hh  

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public class SiteFileFetch extends Thread { uH=Gt^_  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 5#P: "U  
long[] nStartPos; //开始位置 2"zIR(  
long[] nEndPos; //结束位置 0NVG"
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]y$)%J^T  
long nFileLength; //文件长度 [;Vi~$p|Eo  
boolean bFirst = true; //是否第一次取文件 rT o%=0P  
boolean bStop = false; //停止标志 1XQ87~  
File tmpFile; //文件下载的临时信息 E8+8{ #f;  
DataOutputStream output; //输出到文件的输出流 vsjM3=  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Bk@bN~B4  
public SiteFileFetch(SiteInfoBean bean) throws IOException 20n%o&kG]8  
{ oUCS|  
siteInfoBean = bean; $B*qNYpPy.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); HH+TjX/b  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); bL+sN"Km  
if(tmpFile.exists ()) NuHL5C?To  
{ Mp!2`4rD  
bFirst = false; XL=
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read_nPos(); O^y$8OKEi,  
} 0qOM78rE  
else  'Dnq+  
{ 4 3}qaf[  
nStartPos = new long[bean.getNSplitter()]; -v;iMEZ)  
nEndPos = new long[bean.getNSplitter()]; //VG1@vaVX  
} LPsh?Ca?N  
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s  
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} $hC~af6  
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public void run() 4U_rB9K$  
{ o-~-F+mj#  
//获得文件长度 gGF$M `  
//分割文件 ^.nwc#  
//实例FileSplitterFetch |L*6x S[  
//启动FileSplitterFetch线程 9 Wxq)  
//等待子线程返回 ytg7p5{!i  
try{ .0rJIO  
if(bFirst) c"6Kd$?M  
{ $XU-[OF%:9  
nFileLength = getFileSize(); ^!N;F"  
if(nFileLength == -1) ~Ay  
{ 3 t~X:  
System.err.println("File Length is not known!"); <t% Ao,"  
} Fj'\v#h  
else if(nFileLength == -2) R
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{ h;&&@5@lM  
System.err.println("File is not access!"); 0;.e#(`-  
} 1t!&xvhG  
else |j\eBCnH3  
{ OFJJ-4[_3  
for(int i=0;i<nStartPos.length;i++) c }g$1of87  
{ \mqhugy  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \UVT_=Y  
} F0DPS:c  
for(int i=0;i<nEndPos.length-1;i++) DK2c]i^|=  
{ TiwHLb9  
nEndPos = nStartPos[i+1]; :FEd:0TS  
} Lqy|DJ%  
nEndPos[nEndPos.length-1] = nFileLength; gEX:S(1QP  
} k i~Raa/e  
} &QiAM`MbC=  
/ nC$?w  
:/I={)5  
//启动子线程 pP=_@3 D  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; M)bC%(xJ  
for(int i=0;i<nStartPos.length;i++) Zb5T90s%  
{ p]atH<^;K  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1aXIhk4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), DR#3njjEC  
nStartPos,nEndPos,i); P2<gHJ9t  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?etj.\q6  
fileSplitterFetch.start(); lk5_s@V l  
} 7!]k#|u  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aC $h_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); F!DrZd>\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", YB(#]H|8S  
nEndPos = " + nFileLength); L>|A6S#y8/  
// fileSplitterFetch[nPos.length-1].start(); fh/)di  
wFH(.E0@Q  
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//等待子线程结束 nJ
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//int count = 0; kr &:;  
//是否结束while循环 5cv, >{~5  
boolean breakWhile = false; ePFC$kMn  
qCv}+d)  
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while(!bStop) ~}FLn9@*  
{ lUm}nsp=X  
write_nPos(); lW@
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Utility.sleep(500); (]GY.(F{  
breakWhile = true; `qQQQ.K7)z  
+#2@G}j  
y2d_b/  
for(int i=0;i<nStartPos.length;i++) dvH67 x  
{ {ILQ CvP*  
if(!fileSplitterFetch.bDownOver) aG8;,H=%,  
{ J[Ylo&w3  
breakWhile = false; 0.3[=a43  
break; |$i1]Dr6  
} dRarNW  
}
#&HarBxx  
if(breakWhile) )xXrs^  
break; ./z"P]$
 
]MBJ"1F  
}T&;*ww  
//count++; 0Mzc1dG:  
//if(count>4) }p
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// siteStop(); `^@g2c+d  
} 4%W
n}@  
h_}BmJh_  
?7uStqa  
System.err.println("文件下载结束！"); KH CdO  
} M 2U@gC|{  
catch(Exception e){e.printStackTrace ();} IT
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} iKCTYXN1(  
wLg:YM"  
c"_H%x<[  
//获得文件长度 +RKE|*y  
public long getFileSize() o Q!g!xz  
{
7cQHRM+1  
int nFileLength = -1; R&d_WB4w  
try{ }@t'rK[  
URL url = new URL(siteInfoBean.getSSiteURL()); i(TDJ@}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tI6USN%  
httpConnection.setRequestProperty("User-Agent","NetFox"); }G0.Lq+a  
Q{)F$]w  
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int responseCode=httpConnection.getResponseCode(); A/W7;D  
if(responseCode>=400) {e!uvz,e  
{ ^Xz`hR   
processErrorCode(responseCode); 67hPQ/S1  
return -2; //-2 represent access is error AF{7<v>/P  
} I
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H;"N|pBy  
#h|,GvmF<b  
String sHeader; lQ(BEv"2G[  
-n$rKEC4  
y*TNJJ|  
for(int i=1;;i++) "=0lcbC  
{ .$T:n[@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Yk*57&QI  
//Utility.log(in.readLine()); 0OoO cc  
sHeader=httpConnection.getHeaderFieldKey(i); ^#6%*(D  
if(sHeader!=null) =Z$=-\<x0.  
{ kA9 X!)2w  
if(sHeader.equals("Content-Length")) \Q BpgMi(  
{ qS`|=5f  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F(kRAe;  
break; 26klW:2*  
} ?tM].\  
} DcvmeGl  
else ():?FJM  
break; 5In8VE !P  
} GzE3B';g
 
} vdX~E97  
catch(IOException e){e.printStackTrace ();} (YWc%f4  
catch(Exception e){e.printStackTrace ();} -X[8soz  
h[v3G<C~r  
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Utility.log(nFileLength); jgfP|oD  
"rlSK >`  
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return nFileLength; X9BBnZ  
} U=<.P;+f9  
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//保存下载信息（文件指针位置） e, 3(i!47  
private void write_nPos() *
,=
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{ ;<ma K*f\S  
try{ d+| !6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +!Gr`&w*)  
output.writeInt(nStartPos.length); \:)o'-  
for(int i=0;i<nStartPos.length;i++) >"My\o  
{ !/lYq;$R  
// output.writeLong(nPos); o_^d>Klb8  
output.writeLong(fileSplitterFetch.nStartPos); af5`ktx  
output.writeLong(fileSplitterFetch.nEndPos); _=M'KCL*)  
} sYW)h$p;D  
output.close(); 4Xho0lO&  
} wjGjVTtHs  
catch(IOException e){e.printStackTrace ();} HC`3AQ12!&  
catch(Exception e){e.printStackTrace ();} ,(Hmk(,  
} .2-JV0
  
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9^h%}>  
//读取保存的下载信息（文件指针位置） VX@G}3Ck  
private void read_nPos() -{sv3|P>  
{ NqfDY  
try{ *"bp}3$^^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Y{:/vOj  
int nCount = input.readInt(); = 8e8!8  
nStartPos = new long[nCount]; T7_ SO,X  
nEndPos = new long[nCount]; tcdn"]#U  
for(int i=0;i<nStartPos.length;i++) ^%/5-0?xE  
{ aI#n+PW  
nStartPos = input.readLong(); 'ah0IYe  
nEndPos = input.readLong(); '/*rCB  
} = y,avR  
input.close(); J^a"1|  
} sWCm[HpG  
catch(IOException e){e.printStackTrace ();} [<I `slK  
catch(Exception e){e.printStackTrace ();} zi&d  
} g#2X'%&+  
3jVm[c5%]  
)'CEWc%  
private void processErrorCode(int nErrorCode) ]|BSX-V.%i  
{ 5K-)X9z?  
System.err.println("Error Code : " + nErrorCode); )CTM  
} e*Med)tc^$  
g>-[-z$E3  
*^5,7}9Qo  
//停止文件下载 xa*gQ%+F  
public void siteStop() nAC#_\  
{ ASU\O3%%  
bStop = true; `GWq3c5  
for(int i=0;i<nStartPos.length;i++) >^ar$T;Ys  
fileSplitterFetch.splitterStop(); R}26"+~  
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} 1iW9?=a"  
} >Ga1p'8FtU  
//负责部分文件的抓取 y5D?Bg|M  
**FileSplitterFetch.java Cb-E<W&2D  
*/ odn`%ok  
package NetFox; qP'g}Pc  
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import java.io.*; TAoR6aE  
import java.net.*; z$5C(!)  
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#Kr.!uD  
public class FileSplitterFetch extends Thread { E\N=p&g$  
 (t['  
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String sURL; //File URL ?0%TE\I8  
long nStartPos; //File Snippet Start Position 0l@+xS;  
long nEndPos; //File Snippet End Position lM%fgyX  
int nThreadID; //Thread's ID -B(KQT,J  
boolean bDownOver = false; //Downing is over >D#}B1(!  
boolean bStop = false; //Stop identical X1dG'PQ  
FileAccessI fileAccessI = null; //File Access interface GP'Y!cl  
:vT%5CQ  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :J-5Q]#  
{ ~B\:  
this.sURL = sURL; HwuPjc#
 
this.nStartPos = nStart; %.U{):lNx  
this.nEndPos = nEnd; {3Wc<&D C1  
nThreadID = id; k4rBS  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 93DBZqN  
} ,RO(k4  
.p}Kl$K]
 
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public void run() T+D]bfjr&&  
{ <~+  
while(nStartPos < nEndPos && !bStop) N+75wtLy&  
{ &/?jMyD@  
h'
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try{ rv%[?Ml  
URL url = new URL(sURL); 2f4c;YS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lHqx}n@e  
httpConnection.setRequestProperty("User-Agent","NetFox"); jy2nn:1#^  
String sProperty = "bytes="+nStartPos+"-"; +}/!yQtH  
httpConnection.setRequestProperty("RANGE",sProperty); 59]9-1" +  
Utility.log(sProperty); W10fjMC}^  
/D+$|kmW]  
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InputStream input = httpConnection.getInputStream(); ~Xw?
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//logResponseHead(httpConnection); D|:sSld @  
.Tv(1HAc2l  
9#6/c  
byte[] b = new byte[1024]; #Q7$I.O]  
int nRead; N Z`hy>LF^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6Qu*
'  
{ FM[T
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nStartPos += fileAccessI.write(b,0,nRead); RY<b]|  
//if(nThreadID == 1) Uk6!Sb  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )&Bv\Tfjt  
} j}l8k@f  
3>Snd9Q  
;~1JbP  
Utility.log("Thread " + nThreadID + " is over!"); w'XgW0j{  
bDownOver = true; efR$s{n!  
//nPos = fileAccessI.write (b,0,nRead); NM.B=<Aw*  
} `1]9(xwhQ0  
catch(Exception e){e.printStackTrace ();} fk1f'M)/8  
} >t(@?*ZFT  
} %'z3es0  
): C4}&l  
3)SZVME1Z  
//打印回应的头信息 Q$j48,e  
public void logResponseHead(HttpURLConnection con) c"1d#8J  
{ @D=`iG%  
for(int i=1;;i++) hh&y2#Io  
{ 5zOSb$;  
String header=con.getHeaderFieldKey(i); B,,d~\  
if(header!=null) >,Z{wxzJ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ao$z)<d'  
Utility.log(header+" : "+con.getHeaderField(header)); [^~9wFNtd  
else 
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break; !k9h6/b6  
} 2s%M,Nb  
} NhX.yLb$   
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s#ZH.z@J  
public void splitterStop() IOl"Xgn5  
{ 7gcG|kKT  
bStop = true; ze N!*VG  
} O]eJQ4XN<  
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} FoCkTp+/  
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/* 7!wnx.  
**FileAccess.java 8Oh3iO  
*//文件访问(定位，写) 3HR]TQ%r  
package NetFox; QPE.b-S  
import java.io.*; `wd*&vl  
s;$TX304
 
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public class FileAccessI implements Serializable{ !5t 3Y  
S'p`ECfVMA  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 tuV?:g?  
RandomAccessFile oSavedFile; #!# X3j  
long nPos; Gi4dgMVei  
Wb
4{*~  
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public FileAccessI() throws IOException :=v{inN  
{ #q.G_-H4J@  
this("",0); 6*33k'=;F  
} ?^4sE-C6  
[:@?,?V\N  
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public FileAccessI(String sName,long nPos) throws IOException 6
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{ KXCmCn  
oSavedFile = new RandomAccessFile(sName,"rw"); Q9tE^d+%  
this.nPos = nPos;
qFbUM;  
oSavedFile.seek(nPos); )0MshgM  
} })vr*[  
E?U]w0g  
u(WQWsN  
public synchronized int write(byte[] b,int nStart,int nLen) rss.F3dK  
{ w*}yw"gP*0  
int n = -1; [iy;}5XK  
try{ ~c$ts&Cl  
oSavedFile.write(b,nStart,nLen); C?|3\@7  
n = nLen; ~9
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} [c[MQA0  
catch(IOException e) ~U6YN_W  
{ utJVuJw:t  
e.printStackTrace (); #(g+jb0E  
}
~<OjXuYu  
i/~QJ1C  
h^$
}1[  
return n; 2BA9T nxC  
} - :z5m+  
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} q)xl$*g
 
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/* - zw{<+;  
**SiteInfoBean.java ^J~A+CEf"W  
*/ TM}'XZ&  
package NetFox; _s-HlE?C  
5po'(r|U  
e0WSHg=6@  
public class SiteInfoBean { |aAWWd5  
=C>`}%XT}  
zQ %z"tQ  
private String sSiteURL; //Site's URL 2*wO5v  
private String sFilePath; //Saved File's Path >fA@tUQB  
private String sFileName; //Saved File's Name \"`>-v"h
 
private int nSplitter; //Count of Splited Downloading File UAXF6
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KSB_%OI1  
OK
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public SiteInfoBean() L[Yp\[#-q  
{//nSplitter的缺省值为5 {F+M&+``  
//default value of nSplitter is 5 s?x>Yl %  
this("","","",5); 'BdmFKy1  
} oT (:33$  
0mD;.1:  
hi D7tb=g~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) m|2]lb  
{ $< K)fbG  
sSiteURL= sURL; hN:F8r+DG  
sFilePath = sPath; jw(>@SXz  
sFileName = sName; OWXye4`*  
this.nSplitter = nSpiltter; %X,B-h^  
m9<%v0r  
#+Yp^6zg  
} Sa?5iFg  
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public String getSSiteURL() oD#<?h)(  
{ J6( RlHS;  
return sSiteURL; +>WC^s  
} qz=#;&ZU  
<r+!hJ[s'  
,*nZf|  
public void setSSiteURL(String value) g y e(/N+I  
{ <.=#EV^i  
sSiteURL = value; QTjftcu  
} <V:<x  
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public String getSFilePath() H MjeGO.i  
{ &Ky 
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return sFilePath; k Kp6  
} bxhg*A  
2
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<{NYD.  
public void setSFilePath(String value) h-b5   
{ h/X5w4  
sFilePath = value; )
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} {NY~JF
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yXTK(<'  
-q&7J' N  
public String getSFileName() "0H56#eW  
{ oWx_O-_._  
return sFileName; R7B,Q(q2-  
} :e&n.i^  
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u JQaHL!  
public void setSFileName(String value) dm,}Nbc91(  
{ (,Ja  
sFileName = value; qF{DArc  
} ;naq-%'Sg  
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rWFcIh5  
public int getNSplitter() {7=WU4$  
{ 'ybth
 
return nSplitter; $W/+nmb)@K  
} ."IJmv  
aVQSN  
xI@$aTGq  
public void setNSplitter(int nCount) A{aw< P|+  
{ (aJP: ^  
nSplitter = nCount; :>P4L,Da]  
} 8Q^6ibE  
} *,W!FxJ  
c/<Sa|
'  
$"sq4@N
 
/* g=FDm*  
**Utility.java 5?5-;H  
*/ wc7mJxJxA  
package NetFox; _(oP{wgB  
v
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~_u*\]-  
public class Utility { 15xd~V?ai:  
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public Utility() /ojO>Y[<   
{ Sa;<B:|  
t;.^K\S4  
@K$VV^wp  
} %@lV-(5q  
Lj&1K~U  
//线程睡眠 n5Nan  
public static void sleep(int nSecond) :!JpP R5  
{ _{LN{iqDv  
try{ yn/?= ?0  
Thread.sleep(nSecond); L$+d.=]  
} #`jE%ONC  
catch(Exception e) jl.okWuiY  
{ .M9d*qp`S  
e.printStackTrace (); }+91s'/c  
} >=-GD2WK  
} h4CTTe)  
=tr1*s{  
//日志 RzA2*]%a  
public static void log(String sMsg) K*R)V/B/l  
{ `fBG~NDw  
System.err.println(sMsg); -}{%Q?rYj  
} qQfqlD<  
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Gb(C#,xbK  
public static void log(int sMsg) nG"tO'J6  
{ 
@+'c+
  
System.err.println(sMsg); k}-yOP{  
} :/C ?
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} ;^R A!Nj  
.:}.b"%m  
#ZG3|#Q=L  
/* <y@,3DD3A9  
**TestMethod.java C#MFpT  
*/ M{`/f@z(  
package NetFox; :s'o~  
-O|&c9W.O  
-DTB6}kw  
public class TestMethod { /> ^@ O  
Yim{U:F  
J=I:T2bV&s  
public TestMethod() WnD^F>  
{ ///xx/weblogic60b2_win.exe @S
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try{ m7$8k@r  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -Y*VgoK%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); u~s Sk  
SiteFileFetch fileFetch = new SiteFileFetch(bean); iO!27y  
fileFetch.start(); Zimh_  
} )!tCC-Cr  
catch(Exception e){e.printStackTrace ();} B\Xh3l]+j  
F-_%>KJS  
;wJ~haC  
} $o]r]#B+  
:w@F?:C  
81~Kpx  
public static void main(String[] args) uxWFM $  
{ V,V*30K5  
new TestMethod(); 6}ce1|mkg/  
}
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} IUOxGJ|rO  
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