http断点续传简单实现（java)

/* ,;O+2TX  
**SiteFileFetch.java 9FX'Uws  
*/ /tJJ2 =%l  
package NetFox; #`<|W5  
import java.io.*; OY51~#BF  
import java.net.*; u(\b1h n  
.?[2,4F;  
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public class SiteFileFetch extends Thread { wP+wA}SN  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 6S2D\Bt,_  
long[] nStartPos; //开始位置 31 QT  
long[] nEndPos; //结束位置 jQj`GnN|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |TkMrj0  
long nFileLength; //文件长度 X@\rg}kP  
boolean bFirst = true; //是否第一次取文件 zo7Hm]W`  
boolean bStop = false; //停止标志 v5;c}n  
File tmpFile; //文件下载的临时信息 S$=])^dur  
DataOutputStream output; //输出到文件的输出流 0V}%'Ec<e  
@2L+"=u#  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） R8W{[@  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5WP)na6"  
{ V'mQ{[{R  
siteInfoBean = bean; vO&%sjvH  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); &+xNR2";  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |/
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if(tmpFile.exists ()) }<[@)g.h.  
{ f-k%P$"X&  
bFirst = false; lN<v
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read_nPos(); jRmv~]  
} q#xoM1  
else >j4;{r+eQw  
{ -L NJ*?b  
nStartPos = new long[bean.getNSplitter()]; V) a<)  
nEndPos = new long[bean.getNSplitter()]; &j<B22t!  
} ,j:`yB]4,  
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} F *=>=  
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public void run() `WboM\u  
{ Q_$aiE  
//获得文件长度 % r`hW\4{  
//分割文件 V8@VR`!'  
//实例FileSplitterFetch e4fh<0gX  
//启动FileSplitterFetch线程 7y5`YJ}!  
//等待子线程返回 Cvry
8B  
try{ C< 3`]l  
if(bFirst) F{WV}o=MY  
{ i882r=TE3  
nFileLength = getFileSize(); 2F%2K?$`Ej  
if(nFileLength == -1) *|{1`{8n  
{ }`ox;Q  
System.err.println("File Length is not known!"); Q'5]E{1<'n  
} J~Uq'1?  
else if(nFileLength == -2) : E[\1  
{ BpBMFEiP  
System.err.println("File is not access!"); i/E"E7  
} |(u6xPs;P  
else L{1MyR7`I+  
{ (yA`h@@WS  
for(int i=0;i<nStartPos.length;i++) UCV1{  
{ O$zXDxn  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); L|ZxB7xk  
}  PgIH(  
for(int i=0;i<nEndPos.length-1;i++) (SGX|,5X7  
{ ]Y111<Ja  
nEndPos = nStartPos[i+1]; w_qX~d/  
} xKl\:}Ytp  
nEndPos[nEndPos.length-1] = nFileLength; a;bmZh  
} o|`[X'  
} nl<TM96  
u+EZ"p;o  
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//启动子线程 4
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P^[eTR*?  
for(int i=0;i<nStartPos.length;i++) *I]/ [d  
{
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sbv2*fno5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p{|!LcSU$2  
nStartPos,nEndPos,i); fk&>2[^&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $Mg[e*ct  
fileSplitterFetch.start(); V#X#rDfJZ  
} boS=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B@w/wH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }TQa<;Q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0\zY?UUww  
nEndPos = " + nFileLength); "w&IO}j;=  
// fileSplitterFetch[nPos.length-1].start(); iX%9$Bft<  
W6gI#  
=j~BAS*"  
//等待子线程结束 -\<\OV:c*  
//int count = 0; 'VgEf:BS  
//是否结束while循环 xO[V>Ud  
boolean breakWhile = false; @yM
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fn
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while(!bStop) GJ5R <f9I  
{ S86,m=  
write_nPos(); A^ofs*"Y  
Utility.sleep(500); /q,vQ[R/  
breakWhile = true; j*\oK@  
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for(int i=0;i<nStartPos.length;i++) A(_HMqA]  
{ {p.^E5&  
if(!fileSplitterFetch.bDownOver) E
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{ nW)?cQ I  
breakWhile = false; sZI"2[bk  
break; e"y-A&|  
} Mz6\T'rC  
} :.9Y  
if(breakWhile) Z`_x|cU?J  
break; -Uan.#~S  
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Qr\eT}  
//count++; inY_cn?  
//if(count>4) v
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// siteStop(); up{0ehr  
} uI$n7\G!  
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System.err.println("文件下载结束！"); v%$l(  
} JH| D  
catch(Exception e){e.printStackTrace ();} eL>wKu:r  
} j!@T@ 8J  
Siq]Ii0F;>  
9

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//获得文件长度 #]dq^B~~  
public long getFileSize() &#JYh=#  
{ Mq#m
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int nFileLength = -1; 9Nps<+K  
try{ 1d~d1Rd  
URL url = new URL(siteInfoBean.getSSiteURL()); &c 2Qa  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -<g[P_#  
httpConnection.setRequestProperty("User-Agent","NetFox"); \s%g'g;  
0Ix,c(%  
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int responseCode=httpConnection.getResponseCode(); KTt+}-vP^  
if(responseCode>=400) i6P}MtC1  
{ \?oT.z5VG&  
processErrorCode(responseCode);  71@kIJI  
return -2; //-2 represent access is error c0Bqm  
} *+zFsu4l  
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String sHeader; ^SsdM#E  
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for(int i=1;;i++) A9N8Hav  
{ R(pQu! K4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); b+q'xnA=>  
//Utility.log(in.readLine()); ZnJJ-zP  
sHeader=httpConnection.getHeaderFieldKey(i);  ]Tb?z&  
if(sHeader!=null) H>D sAHS  
{ ;~DrsQb  
if(sHeader.equals("Content-Length")) pY-!NoES  
{ ovOV&Zt  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `q\F C[W  
break; @I|kY5'c  
} QnOs8%HS-  
} *J]p/<> {  
else AA)pV-  
break; eaNfCXHDN  
} "=K3sk  
} I L7kpH+y  
catch(IOException e){e.printStackTrace ();} Z2@e~&L  
catch(Exception e){e.printStackTrace ();} ^V1\boo=  
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[kpQ:'P3
 
Utility.log(nFileLength); mE1Vr  
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return nFileLength; cAGM|%  
} ^t71${w##  
>TM{2b,(p  
>Ik%_:CC`  
//保存下载信息（文件指针位置） O"|d~VQ  
private void write_nPos() j~S=kYrGM  
{ >);M\,1\I  
try{ B5+Q%)52  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *2N0r2t&  
output.writeInt(nStartPos.length); 2Mq
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for(int i=0;i<nStartPos.length;i++) 4,W,E4 7  
{ Pzd!"Gl9  
// output.writeLong(nPos); 7O%^4D  
output.writeLong(fileSplitterFetch.nStartPos); %-$ :/N  
output.writeLong(fileSplitterFetch.nEndPos); ZU0*iA  
} x!W5'DO  
output.close(); LjEMs\P\  
} k,'MmAz  
catch(IOException e){e.printStackTrace ();} N"RPCd_  
catch(Exception e){e.printStackTrace ();} b;*'j9ly  
} _qk&W_u  
[-"ZuUG  
<h+@;/v:  
//读取保存的下载信息（文件指针位置） tI^[|@,  
private void read_nPos() Wi5Dl=  
{ N}[!QE  
try{ NOoF1
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); lTN^c?  
int nCount = input.readInt(); C8qSoO4Z  
nStartPos = new long[nCount]; p
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nEndPos = new long[nCount]; :5&UWL|  
for(int i=0;i<nStartPos.length;i++) @].!}tz  
{ XV4aR3n{Q  
nStartPos = input.readLong(); Uc,

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nEndPos = input.readLong(); _I3"35a  
} O[L#|_BnEO  
input.close(); B]b/(Q+  
} s:_j,/H0A}  
catch(IOException e){e.printStackTrace ();} xQzW6H|  
catch(Exception e){e.printStackTrace ();} FL^t}vA  
}   </5  
`HYj:4v'  
|/8!PKm  
private void processErrorCode(int nErrorCode) ,Csjb1  
{ c=?6`m,"M  
System.err.println("Error Code : " + nErrorCode); `D=d!!1eUi  
} 9&Y|,&W  
IZ^:wIKo{  
+O8zVWr  
//停止文件下载 \Nf#{  
public void siteStop() cH:&S=>h  
{ YSfJUB!I  
bStop = true; e0ni  
for(int i=0;i<nStartPos.length;i++) XDyo=A]  
fileSplitterFetch.splitterStop(); =b1 y*?  
\UM&|yk:  
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} vpdPW%B  
} :P%?!'M  
//负责部分文件的抓取 M0)0~#?.D  
**FileSplitterFetch.java s?k:X ~m  
*/ 1P'L<z  
package NetFox; '"LaaTTs  
U,fPG/9  
>zw@!1{1  
import java.io.*; saQo]6#  
import java.net.*; ,+C?UW  
;Oq>c=9%  
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public class FileSplitterFetch extends Thread { [TqX"@4NS  
i|/G!ht^e  
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String sURL; //File URL =JPY{'VO  
long nStartPos; //File Snippet Start Position SJ;{ Hg  
long nEndPos; //File Snippet End Position \'('HFr,  
int nThreadID; //Thread's ID Eg2jexl
 
boolean bDownOver = false; //Downing is over S+mBVk"-~S  
boolean bStop = false; //Stop identical d>#X+;-k  
FileAccessI fileAccessI = null; //File Access interface H<g8u{ $  
u$ o19n  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Hl{ul'o  
{ jJ2{g> P0P  
this.sURL = sURL; 0lOan  
this.nStartPos = nStart; 0A8G8^T  
this.nEndPos = nEnd; pj3H4yCM:  
nThreadID = id; }"%mP 4]&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 pV 8U`T  
} E6T=lwOZ  
"^ dMCS@  
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public void run() d]sg9`  
{ gdyWuOxa|  
while(nStartPos < nEndPos && !bStop) &H}Xk!q5b^  
{ y0) mBCX  
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try{ 9>&p:+D  
URL url = new URL(sURL); fmLDufx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Y$|KY/)H)  
httpConnection.setRequestProperty("User-Agent","NetFox"); am| 81)|a  
String sProperty = "bytes="+nStartPos+"-"; /%{CJ0Y  
httpConnection.setRequestProperty("RANGE",sProperty); W+s3rS2  
Utility.log(sProperty); #W_-S0>&  
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{aopGu?i  
InputStream input = httpConnection.getInputStream(); LJ z6)kz  
//logResponseHead(httpConnection); EVLDP\w{  
R.GDCGAL  
HuN_$aP  
byte[] b = new byte[1024]; 9c0
  
int nRead; ^0(D2:E  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u:wf:^  
{ "0z4mQ}>N  
nStartPos += fileAccessI.write(b,0,nRead); tTt}=hQpgX  
//if(nThreadID == 1) O[|X=ZwR:l  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); uFvR(LDb&g  
} ]&='E.f  
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Utility.log("Thread " + nThreadID + " is over!"); }%y5<n*v\  
bDownOver = true; $g,v]MW  
//nPos = fileAccessI.write (b,0,nRead); ^7*zi_Q  
} !rZ
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catch(Exception e){e.printStackTrace ();} `C^0YGO%  
} yRp&pUtb  
} X
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= ^%*:iT  
//打印回应的头信息 [BEQ ~A_I  
public void logResponseHead(HttpURLConnection con) %."w]fy>P  
{ idjk uB(6  
for(int i=1;;i++) &IG*;$c!  
{ ,"?8  
String header=con.getHeaderFieldKey(i); ]KUeSg|  
if(header!=null) 7H,)heA  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); W*u$e8i7  
Utility.log(header+" : "+con.getHeaderField(header)); 'W&ewZH_h  
else -x!JTx[K  
break; 2=VFUR 8  
} xd+aO=)Td  
} F&7^M0x\ O  
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r( bA>L*mk  
public void splitterStop() {=MRJg!U  
{ fBBtS S  
bStop = true; @oD2_
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} |[)pQGw  
6|4ID"  

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} Wo5%@C#M  
34J*<B[Njo  
5>VX]nE3!  
/* G#1W":|`  
**FileAccess.java D8WKy  
*//文件访问(定位，写) @=BApuer+  
package NetFox; x+[ATZ([  
import java.io.*; rrG}; A  
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public class FileAccessI implements Serializable{ tHr4/  
D/
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[_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Th$xk9TK^@  
RandomAccessFile oSavedFile; vTC{  
long nPos; 6;(b-D
hi  
(#]9{C;  
  Xi
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public FileAccessI() throws IOException U6YHq2<  
{ =>@ X+4Kb  
this("",0); \~l"  
} 35:R
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d?V/V'T[  
C 1)+^{7ef  
public FileAccessI(String sName,long nPos) throws IOException Qkc9X0J!  
{ VHvL:z  
oSavedFile = new RandomAccessFile(sName,"rw");  pQ7<\8s*  
this.nPos = nPos; L^K,YlNBR  
oSavedFile.seek(nPos); 3Zwhv+CP[  
} Hoi~(Vc.  
MeAY\V%G=o  
]@}o"Td  
public synchronized int write(byte[] b,int nStart,int nLen) }ktK*4<k  
{ b*4aUpW  
int n = -1; q_[`PYT  
try{ at1oxmy  
oSavedFile.write(b,nStart,nLen); +RnWeBXAT
 
n = nLen; <;cch6Z  
} ~yA^6[a=  
catch(IOException e) O9N+<s
U=X  
{ AoK;6je`K^  
e.printStackTrace (); XEN-V-Z%*  
} r>.l^U9hJ  
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_Ih"*~ r/&  
return n; 5JhpBx/>o=  
} dTte4lh  
*xpPD\{k  
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} -lXQQ#V -  
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N x
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/* Mgu9m8 `J  
**SiteInfoBean.java }iLi5Qkx  
*/ )Lk2tvr  
package NetFox; dKL9}:oUa  
e-.(O8  
8cRc5X  
public class SiteInfoBean { A;f)`i0l,  
n7zM;@{7  
= \K/ulZo  
private String sSiteURL; //Site's URL i.7$~}  
private String sFilePath; //Saved File's Path _^!C4?2!  
private String sFileName; //Saved File's Name "cbJ{ G1pk  
private int nSplitter; //Count of Splited Downloading File {96NtR0Z  
]{I>HA5[  
*$/Go8t4u  
public SiteInfoBean() 8 -w|~y';  
{//nSplitter的缺省值为5 FRQkD%k  
//default value of nSplitter is 5 TT){15T;"  
this("","","",5); dkg+_V!  
} &]anRT#  
t*Z-]P  
0t*PQ%  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !L_xcov!Y  
{ BL%&n*&  
sSiteURL= sURL; "`'+@KlE  
sFilePath = sPath; [T,Df&  
sFileName = sName; U<'$ \P  
this.nSplitter = nSpiltter; ?pA_/wwp  
ol_&epG;ST  
/N@NT/.M<  
} 472'P  
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JBISA _Y  
public String getSSiteURL() s GrI%3[e"  
{ 9AD0|,g  
return sSiteURL; i_I`  
} J.0&gP V  
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public void setSSiteURL(String value) ^q<EnsY  
{ QKoJxjR=^  
sSiteURL = value; )EN,Ry  
} `EiL~*  
3V]psZS  
5)w;0{X!P  
public String getSFilePath() aCBq
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{ Qk^}  
return sFilePath; zaE!=-U  
} a$LoQ<f_  
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public void setSFilePath(String value) dBW4%Zh  
{ g#5t8w  
sFilePath = value; 'RR,b*Ql  
} YJwffV}nd  
b+71`aD0  
/NVyzM51V  
public String getSFileName() 57$/Dn  
{ 5WtI.7r  
return sFileName; a & 6-QVk  
} dp:5iuS  
QRER[8]r$  
"+BuFhSLf  
public void setSFileName(String value) BagV\\#v4  
{ 1sfs!b&E  
sFileName = value; ~hU^5R-%  
} 83{v_M  
/?6  
zc>LwX}<  
public int getNSplitter() cLMFC1=b  
{ "o<&3c4  
return nSplitter; SwhArvS  
} 0a)LZp|  
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public void setNSplitter(int nCount) QWK\6  
{ L$f:D2Ei  
nSplitter = nCount; Fi#b0S  
} q.p
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} UC"_#!3  
F#7A6|  
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/* PvS\  
**Utility.java 4iZ7BD  
*/ `"j_]
 
package NetFox; XFvPc  
ixo?o]Xb`  
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public class Utility { +?bOGU
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public Utility() y Ide]  
{ Q 1e hW  
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2sXX0kq~V  
} ngQ]  
O8WLulo  
//线程睡眠 m=%WA5c?  
public static void sleep(int nSecond) ;/.XAxkFL  
{ 9\W }p\c  
try{ [|\BuUT'  
Thread.sleep(nSecond); <YBA 7i  
} >2?O-WXe  
catch(Exception e) uE{nnNZy  
{ A!j6JY.w  
e.printStackTrace (); ^ G(GjW8  
} m\xE8D(,  
} !<xeAo%8  
3xGk@ 333  
//日志 rZv5>aEI  
public static void log(String sMsg) 'X(G><R9  
{ .I&]G  
System.err.println(sMsg); <UcbBcW,  
} o Z#4<7K  
5>'1[e45  
J 4EG  
public static void log(int sMsg) #(G#O1+  
{ kmXaLt2Z  
System.err.println(sMsg); >>C(y?g  
} ^q0Ox&X  
} [LJ1wBMw  
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Z ^tF  
/* W\?_o@d  
**TestMethod.java ]"< `^  
*/ Gmi$Nl!~  
package NetFox;  D|[~Py  
7VdG6`TDR  
qh)o44/ $  
public class TestMethod { df
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M"eiKX  
` qqUuFMM  
public TestMethod() |3?q
L  
{ ///xx/weblogic60b2_win.exe 'K=n}}&:  
try{ TrHz(no  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #lM :BO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0N~AQu  
SiteFileFetch fileFetch = new SiteFileFetch(bean); IZV D.1  
fileFetch.start(); {VPF2JFB[  
} ZCZYgf@  
catch(Exception e){e.printStackTrace ();} h9,ui^#d$  
%z&=A%'a  
c:
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} _-^Lr /`G!  
at@B>Rb  
9WaKsdf  
public static void main(String[] args) (#WE9~Sru  
{ G9.
+N~GZ.  
new TestMethod(); %G& Zm$u=  
} :_%  
} ^@'LF T)  
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