http断点续传简单实现（java)

/* rP;Fh|w#  
**SiteFileFetch.java t22BO@gt74  
*/ pLBp[GQ  
package NetFox; J*,Ed51&7  
import java.io.*; c1CP12  
import java.net.*; j>?H^fB  
_
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public class SiteFileFetch extends Thread { ss,t[`AV{  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #JO#PV%  
long[] nStartPos; //开始位置 q&Q* gEFK  
long[] nEndPos; //结束位置 9|Jmj @9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8o4<F%ot  
long nFileLength; //文件长度 F!`.y7hY@  
boolean bFirst = true; //是否第一次取文件 g=b[V   
boolean bStop = false; //停止标志 $|6Le; K  
File tmpFile; //文件下载的临时信息 DD|%F  
DataOutputStream output; //输出到文件的输出流 \(Zdd \,  
,Xk8{=  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） xHykU;p@  
public SiteFileFetch(SiteInfoBean bean) throws IOException .m/Lon E  
{ ILF
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siteInfoBean = bean; MJV&%E6{:{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); xJ>hN@5}i  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); c2?(.UV  
if(tmpFile.exists ()) 52l|  
{ xYM/{[  
bFirst = false; ^lRXc.c z  
read_nPos(); A~I}[O~(pb  
} %r6~5_A  
else 1oj7R7  
{ WU#bA|Cf  
nStartPos = new long[bean.getNSplitter()]; j^iH[pN] \  
nEndPos = new long[bean.getNSplitter()]; L\_8}\  
} j=dHgnVvj  
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} n?Gm 5##  
x gaN0!  
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public void run() f>ED  
{ 8DLR  
//获得文件长度 U@m<  
//分割文件 \~jt7 Q  
//实例FileSplitterFetch / )5B  
//启动FileSplitterFetch线程 >0@X^o  
//等待子线程返回 "H%TOk7l  
try{ t ~U&a9&Z  
if(bFirst) m++VW0Y>  
{ 1xM&"p:  
nFileLength = getFileSize(); _=q)lt-UY  
if(nFileLength == -1) %Dsa ~{  
{ V}pw ,2s  
System.err.println("File Length is not known!"); N1P[&lR  
} k@4]s_2  
else if(nFileLength == -2) `x6 i5mp  
{ N<Y-]xS  
System.err.println("File is not access!"); '9<Mk-Aj  
} vh?({A#>.E  
else }6C&N8f  
{
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for(int i=0;i<nStartPos.length;i++) .__X[Mzth3  
{ b*dRNu  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1ZhJ?PI,9{  
} :$/lGIz  
for(int i=0;i<nEndPos.length-1;i++) ;13lu1  
{ Ha)w*1&w"  
nEndPos = nStartPos[i+1]; |;rjr_I  
} /kx:BoV  
nEndPos[nEndPos.length-1] = nFileLength; i7e{REBXb  
} D\j1`  
} -U%wLkf|  
8EbYk2j  
_u{D#mmO  
//启动子线程 z56W5g2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |4X:>Ut]  
for(int i=0;i<nStartPos.length;i++) n8zUL1:R  
{ G-M!I`P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,W{Qv<oo  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .t"s>jq 1  
nStartPos,nEndPos,i); 'cH),~ z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vx!nC}f"k`  
fileSplitterFetch.start(); (X>r_4W$  
} ms;Lu-UR  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4"l(rg  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "vU:qwm  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", cQ
3Dk<GZ  
nEndPos = " + nFileLength); "~d)$]+  
// fileSplitterFetch[nPos.length-1].start(); nV:.-JR  
3eI:$1"Q  
/MQd[03]  
//等待子线程结束 2$[u&__E  
//int count = 0; {hg,F?p '  
//是否结束while循环 m]7yc>uDy  
boolean breakWhile = false; CzNSJVE5  
/=m=i%& #  
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while(!bStop) wAkoX  
{ TKRu^KH9  
write_nPos(); /wCP(1Mw  
Utility.sleep(500); nfrC@A
v  
breakWhile = true; J&8l1{gd  
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for(int i=0;i<nStartPos.length;i++) pN*>A^  
{ AU-/-h=Mr  
if(!fileSplitterFetch.bDownOver) f*oL8"?u&  
{ "=yaeEp  
breakWhile = false; v,+2CVdW  
break; ,p$1n;  
} >K50 h  
} Z"e|DP`  
if(breakWhile) >-y'N.l^  
break; I!# 42~\  
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tQ?? nI2  
//count++; oB_{xu$6|  
//if(count>4) Q6.},o  
// siteStop();  U]e;=T:3  
} l6l)M  
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k*z)AR  
System.err.println("文件下载结束！"); \P{VJ^)0  
} 1C.<@IZ  
catch(Exception e){e.printStackTrace ();} H~||]_q|  
} [0MVsc=  
*QAK9mc  
$qIMYX  
//获得文件长度 gtCd#t'(V  
public long getFileSize() q7m-} mBN~  
{ !y4o^Su[  
int nFileLength = -1; "'6KQnpZ  
try{ O$#`he/jm  
URL url = new URL(siteInfoBean.getSSiteURL()); lD !^MqK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~5cLI;4h  
httpConnection.setRequestProperty("User-Agent","NetFox"); E8FS jLZ  
(F$q|qZ%  
{:{NK%  
int responseCode=httpConnection.getResponseCode(); eT}c_h)  
if(responseCode>=400) JRU)AMMU&  
{ W J^r~*r  
processErrorCode(responseCode); B[cZEFo\
 
return -2; //-2 represent access is error 61!R-  
} G.T}^xHmL  
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String sHeader; nW{7L  
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for(int i=1;;i++) B
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{ ;znIY&Z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); tM{t'WU  
//Utility.log(in.readLine()); eCk}B$ 2  
sHeader=httpConnection.getHeaderFieldKey(i); NsWyxcty  
if(sHeader!=null) iSIj ?.  
{ g%RL9-z  
if(sHeader.equals("Content-Length")) ";s?#c  
{ <K4'|HU/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @uT\.W:Q2  
break; 4Hk
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} Cd6^aFoK!  
} LA"`8  
else #,!.
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break; f4`=yj*  
} }1d 6d3b  
} tR0o6s@v/<  
catch(IOException e){e.printStackTrace ();} _j<46^  
catch(Exception e){e.printStackTrace ();} `){*JPl  
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Utility.log(nFileLength); *>S\i7RET  
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return nFileLength; v

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} rJ9a@n,  
)Hl;9  
rDUNA@r  
//保存下载信息（文件指针位置） *4]I#N  
private void write_nPos() Qmzj1e$6x  
{ ldi'@
^  
try{ J%3S3C2*m  
output = new DataOutputStream(new FileOutputStream(tmpFile)); N7}.9%EV  
output.writeInt(nStartPos.length); R;
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for(int i=0;i<nStartPos.length;i++) 3vNoD  
{ ]rC6fNhQ  
// output.writeLong(nPos); c%Kv"Z%f  
output.writeLong(fileSplitterFetch.nStartPos); jo{GPp}  
output.writeLong(fileSplitterFetch.nEndPos); T4o}5sq}S  
} YX!%R]c%  
output.close(); :6N{~[:4  
} 4vp,izNW  
catch(IOException e){e.printStackTrace ();} O<."C=1~E  
catch(Exception e){e.printStackTrace ();} QjF.U8  
} (lS&P"Xi  
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//读取保存的下载信息（文件指针位置） |UBR8  
private void read_nPos() |giK]Z  
{ s26:(J [{  
try{ VU}UK$JN  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >vt#,8VAN  
int nCount = input.readInt(); "2N3L8?k  
nStartPos = new long[nCount]; Ny p5=  
nEndPos = new long[nCount]; Gvl-q1PVC  
for(int i=0;i<nStartPos.length;i++) 76mQ$ze  
{ c i_XcG  
nStartPos = input.readLong(); %+Mi~k*A'  
nEndPos = input.readLong(); `3/,-  
} n=L;(jp<j  
input.close(); <yE(p  
} >77 /e@  
catch(IOException e){e.printStackTrace ();} qW$IpuK  
catch(Exception e){e.printStackTrace ();} =TwV_Dro~  
} DJ[U^dWRn  
KX[_eOL  
>2vl & (  
private void processErrorCode(int nErrorCode) <;SQ1^N  
{ |Tf}8e  
System.err.println("Error Code : " + nErrorCode); dB^J}_wp  
} #@3RYx  
Y>wpla[kUq  
#O\4XZ,Lv  
//停止文件下载 ZQsE07  
public void siteStop() nBWrkVX  
{ z,I7 PY& G  
bStop = true; 3)EslBA7i  
for(int i=0;i<nStartPos.length;i++) ~}$:iyJV(>  
fileSplitterFetch.splitterStop(); K>w}(td  
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} _ZC4O&fL  
} ]cLpLA"  
//负责部分文件的抓取 m:/nw,  
**FileSplitterFetch.java zPH1{|H+l  
*/ J<>z}L{  
package NetFox; Bl3G_Ep  
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9Rb-QI  
import java.io.*; 'g|%Ro/  
import java.net.*; /^P^K  
7==Uz?}C  
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public class FileSplitterFetch extends Thread { v}+axu/?  
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String sURL; //File URL <E&1HeP  
long nStartPos; //File Snippet Start Position D$YAi%*H  
long nEndPos; //File Snippet End Position pvDr&n9  
int nThreadID; //Thread's ID /-8v]nRB  
boolean bDownOver = false; //Downing is over wU2y<?$\8  
boolean bStop = false; //Stop identical >Y1?`  
FileAccessI fileAccessI = null; //File Access interface nyw,Fu  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1AjsAi,7;2  
{ w4:n(.;HK  
this.sURL = sURL;  S`U Gk  
this.nStartPos = nStart; ~SUA.YuF  
this.nEndPos = nEnd; L<1"u.3Z`}  
nThreadID = id; "of(,p  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (W5E\hjJ  
} x98LOO  
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public void run() |n}W^}S5  
{ LJc w->  
while(nStartPos < nEndPos && !bStop) {,]BqFXv  
{ ^t*+hFEI  
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try{ +&4PGv53J  
URL url = new URL(sURL); P>)-uLc~W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -E2[PW4$  
httpConnection.setRequestProperty("User-Agent","NetFox"); .sbU-_ij@U  
String sProperty = "bytes="+nStartPos+"-"; Ua5m2&U1  
httpConnection.setRequestProperty("RANGE",sProperty); `]LaX&u  
Utility.log(sProperty); ^n@iCr9  
`yP-,lA$  
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InputStream input = httpConnection.getInputStream(); ~BERs;4  
//logResponseHead(httpConnection); 6x]|IW
vW
 
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byte[] b = new byte[1024]; 6lT1X)  
int nRead;
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) hO;bnt%(  
{ Kp~k!6x  
nStartPos += fileAccessI.write(b,0,nRead); nKu`Ta*fX  
//if(nThreadID == 1) #7lkj:j4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qt^%jIv  
} 66p_d'U  
#xW%RF  
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Utility.log("Thread " + nThreadID + " is over!"); c`doR(oZ  
bDownOver = true; u8+<uWB  
//nPos = fileAccessI.write (b,0,nRead); X-:Ni_O\ty  
}
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catch(Exception e){e.printStackTrace ();} Ef%
8+_  
} ^b-H  
} n 8AND0a1C  
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//打印回应的头信息 :Jhx4/10  
public void logResponseHead(HttpURLConnection con) GVn
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{ m9#u.Q*  
for(int i=1;;i++) R#Bt!RNZ  
{  o<Y|N  
String header=con.getHeaderFieldKey(i); &=$8 v"&^  
if(header!=null) VZAdc*X  
//responseHeaders.put(header,httpConnection.getHeaderField(header));
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Utility.log(header+" : "+con.getHeaderField(header)); LTzf&TZbx5  
else  %ef+
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break; !PUhdW  
} KO)<Zh  
} s3J T1TX  
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public void splitterStop() \?3];+c9  
{ nJ*NI)  
bStop = true; AQQj]7Y  
} oC4rL\d
{  
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} l' "<  
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/* l\$C)q6O  
**FileAccess.java /23v]HEPy  
*//文件访问(定位，写) y:2o-SJn  
package NetFox; LR9'BUfFv  
import java.io.*; "H G:by  
?7G[`@^Y  
'kx{0J?  
public class FileAccessI implements Serializable{ KJ9~"v  
U]R7=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 l" sR\`~  
RandomAccessFile oSavedFile; k?J}-+Bm[|  
long nPos; jWU)y)$  
|?g2k:fzB7  
&Q&$J )0  
public FileAccessI() throws IOException $7BD~U  
{ X0!48fL*  
this("",0); |#-Oz#Eg'  
} koqH~>ZtD  
(1Kh9w:^"  
X;6X K$"  
public FileAccessI(String sName,long nPos) throws IOException Nm;ka&'  
{ P AKh v.7  
oSavedFile = new RandomAccessFile(sName,"rw"); mS%D" e  
this.nPos = nPos; w6wXe_N+M  
oSavedFile.seek(nPos); el[6E0!@  
} Pt1Htt:BE  

$}\.)^[}  
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public synchronized int write(byte[] b,int nStart,int nLen) |2
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{ tGf  
int n = -1; V'6%G:?0a  
try{ "arbUX~d  
oSavedFile.write(b,nStart,nLen); kwyvd`J8  
n = nLen; ,$*IJeKx  
} 6'Lij&,f?{  
catch(IOException e) t;4{l`dk  
{ FJ2^
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e.printStackTrace (); Pd@?(WQ  
} GQ[\R&]q<  
9^aMmN&6N2  
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return n; bF}~9WEa  
} 2smLv1w@  
^
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}  oR5
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/* qvab>U`  
**SiteInfoBean.java 0&w.QoZY(  
*/ 43(+3$VM7  
package NetFox; *.i`hfRc  
C"YM"9JSJ  
QU\|RX
 
public class SiteInfoBean { e<IT2tv>u  
(IEtjv}D  
U`:$1*(`  
private String sSiteURL; //Site's URL p~M^' k=d  
private String sFilePath; //Saved File's Path RE*SdazY?  
private String sFileName; //Saved File's Name yuhSP{pv'  
private int nSplitter; //Count of Splited Downloading File >S!QvyM(V  
ft$/-;  
Rr:,'cXGi  
public SiteInfoBean() %*Y:Rm'>  
{//nSplitter的缺省值为5
sYp@.?Tz  
//default value of nSplitter is 5 k.rZj|7 L  
this("","","",5); VV?KJz=,W=  
} :PjHsNp;^  
EY&hWl*a^  
/<M08ze  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) G#K=n  
{ zQD$+q5h  
sSiteURL= sURL; ~KCOCtiD  
sFilePath = sPath; :,:r
  
sFileName = sName; /(XtNtO*  
this.nSplitter = nSpiltter; ;JDxl-~  
\/'u(|G  
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} up`!r;5-  
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:3
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public String getSSiteURL() Rl-Sr  
{ H}X3nl\]  
return sSiteURL; RXLD5$s^  
} gNN{WFHQX:  
%5a>@K]  
mZ*!$P:vy"  
public void setSSiteURL(String value) >8HcCG  
{ }<A\>  
sSiteURL = value; vJ }^p}  
} MyAi)Mz~o  
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public String getSFilePath() RCo!sZP}  
{ quVTqhg
"  
return sFilePath; ti3T?_  
} /J8y[aa  
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U c$RYPq  
public void setSFilePath(String value) 9SXFiZA(r  
{ HTvA]-AuM  
sFilePath = value; s9@/(_  
} Hh4$Qr;R  
[C9->`(`  
y2yW91B,  
public String getSFileName() J9zSBsp_  
{ DH
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return sFileName; p,Qr9p3y  
} G!uoKiL  
j0~]o})@i  
8:|F'{<<b  
public void setSFileName(String value) V31<~&O~%  
{ 1c8J yp  
sFileName = value; >/Gz*.  
} NDWpV  
2X!O
'  
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public int getNSplitter() bb`GV  
{ -O:+?gG  
return nSplitter; Om,+59ua*  
} Oca_1dlx  
#qtAFIm'  
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public void setNSplitter(int nCount) 4RGEg;]S  
{ ba^B$$?Bo  
nSplitter = nCount; yF8 av=<{  
} Ep>3%{V  
} q;3.pRw(  
;!v2kVuS]  
F#*vJb)  
/* $e)d!m.  
**Utility.java @`^+XPK\  
*/ FctqE/>}I  
package NetFox; S!j=hj@qW  
L<'3O),}  

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public class Utility { Ne!F p  
=UE/GTbl  
ms@*JCL!t  
public Utility() aVN
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{ "7mYs)=  
$6
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} $O9Nprf  
qpjtF'  
//线程睡眠 ,5$V;|  
public static void sleep(int nSecond) ;jS2bc:8a  
{ [@fw9@_'  
try{ MB06=N  
Thread.sleep(nSecond); (99P9\[p  
} /n;Ll](ri  
catch(Exception e) v]SHude{  
{ S
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e.printStackTrace (); G5a PjP  
} a+sHW<QeS  
} Fr_esx  
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//日志 <+I^K 7   
public static void log(String sMsg) ywW
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{ /I&Hq7SW`  
System.err.println(sMsg); ChO?Lm$y  
} r!:W-Y%&#  
1henQiIO  
HxCq6Y_m<  
public static void log(int sMsg) S81Z\=eK  
{ K;moV| j  
System.err.println(sMsg); XHU&ix{Od  
} db#QA#^S  
} kzU;24
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,S[,F0"%  
Rj6:.KEJ  
/* jR-DH]@y  
**TestMethod.java OjO$.ecT  
*/ pn3f{fQ  
package NetFox; 7xz~%xC.  
,Fo7E  
2c:H0O 0o  
public class TestMethod { y Nb&;E7 H  
'D#iT}Vu  
/!J1}S  
public TestMethod() EXn$ [K;  
{ ///xx/weblogic60b2_win.exe ~3-2Iu^F  
try{ E/ %S0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0w^\sf%s  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zWvG];fsN  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $jMU|{  
fileFetch.start(); 'A@[a_  
} s!S,;H  
catch(Exception e){e.printStackTrace ();} F%QZe*m[  
clfi)-^{K  
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} Ij;=  
q)JG_Y.p  
qT]Bl+h2  
public static void main(String[] args) LL3RC6;e  
{ T{=.mW^ x  
new TestMethod(); DDxNqVVt4  
} .gUceXWH3  
} CORX .PQ  
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