http断点续传简单实现（java)

/* >$L7J=Em  
**SiteFileFetch.java a
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*/ EGQgrwY5  
package NetFox; Q+9:]Bt  
import java.io.*; ".(vR7u'  
import java.net.*; |.0~'  
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public class SiteFileFetch extends Thread { ~h;   
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SiteInfoBean siteInfoBean = null; //文件信息Bean aXJ/"k #Tl  
long[] nStartPos; //开始位置 6Jb0MX"AVr  
long[] nEndPos; //结束位置 NGl 8*Af
 
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3,{eH6,O7M  
long nFileLength; //文件长度 7K
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boolean bFirst = true; //是否第一次取文件 rMbq_
5}
 
boolean bStop = false; //停止标志 DlE,aYB  
File tmpFile; //文件下载的临时信息 j7kX"nz  
DataOutputStream output; //输出到文件的输出流 kF~(B]W(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .G!xcQ`?  
public SiteFileFetch(SiteInfoBean bean) throws IOException =zK4jiM1  
{ 4hwb] Yz  
siteInfoBean = bean; rVNx2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); b2UDPW  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); k!0O[U  
if(tmpFile.exists ()) g}D)MlXRq  
{ 7N[".V]c  
bFirst = false;
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read_nPos(); ?8"*B^*Sh  
} X%IqZ{{  
else -GPJ,S V>  
{ CMW4Zqau*  
nStartPos = new long[bean.getNSplitter()]; U\?D;ABQ%  
nEndPos = new long[bean.getNSplitter()]; 49&i];:%7%  
} S1U0sP@o  
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} .c+U=bV-  
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public void run() (is',4^b  
{ $ItmYj.m  
//获得文件长度 s"`~Xnf  
//分割文件 m.m6.  
//实例FileSplitterFetch nXLz<wE  
//启动FileSplitterFetch线程 j}ob7O&U'w  
//等待子线程返回 Mu[lk=jC  
try{ #:gl+  
if(bFirst) 2M
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{ : "|/  
nFileLength = getFileSize(); fc*>ky.v  
if(nFileLength == -1) h2Nt@  
{
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System.err.println("File Length is not known!"); OA&'T*)-A6  
} E.Xp\Dm71  
else if(nFileLength == -2) H@1'El\9  
{ $kTm"I  
System.err.println("File is not access!"); &<98nT  
} H}F UgA;  
else \+R%KA/F  
{ xX%ppD7  
for(int i=0;i<nStartPos.length;i++) vF$( Y/  
{ l[$GOLeS  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cj>UxU][eS  
} ?uSoJM`wa!  
for(int i=0;i<nEndPos.length-1;i++) *HR pbe2  
{ ?K[Y
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nEndPos = nStartPos[i+1]; j9>[^t3U  
} Unb2D4&'  
nEndPos[nEndPos.length-1] = nFileLength; KSchgon0V  
} qKfUm:7Q_  
} eavn.I8J  
:6nD"5(  
qhGz2<}_j  
//启动子线程 bQautRW  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; HXKM
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for(int i=0;i<nStartPos.length;i++) q8d](MaX  
{ Ow/,pC >V  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), gD6S%O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), sWr;%<K  
nStartPos,nEndPos,i); p6<JpW5@_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (NLw#)?  
fileSplitterFetch.start(); prj(  
} y<FC
7  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2@ZVEN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); U_*,XLU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", n>,:*5"G  
nEndPos = " + nFileLength); (a_bU5)  
// fileSplitterFetch[nPos.length-1].start(); D0jV}oz  
u?`{s88_mF  
/(JG\Ut  
//等待子线程结束 l{dsm1#W~  
//int count = 0; 9?,i+\)qK@  
//是否结束while循环 fY&TI}Y  
boolean breakWhile = false; T&'Jc  
-H6[{WVW!  
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while(!bStop) MTtx|L\4  
{ ej-A=avd  
write_nPos(); %JE>Z]  
Utility.sleep(500); 4}m9,  
breakWhile = true; N4+Cg t(  
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for(int i=0;i<nStartPos.length;i++) g9" wX?*  
{ 61H_o7XXk  
if(!fileSplitterFetch.bDownOver) l%EvXdZuOy  
{ AaYH(2m-  
breakWhile = false; X=whZ\EZ  
break; AE77i,Xa  
} _l7_!Il_  
} e|{R2z"^  
if(breakWhile) [=(8yUV'G  
break;
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lk 1\|Q I  
//count++;
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//if(count>4) Kz42AC  
// siteStop(); z='%NZY  
} 1GK.:s6.f  
V gMgeja  
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System.err.println("文件下载结束！"); I%J>~=]n_  
} .3C::~:  
catch(Exception e){e.printStackTrace ();} cZBXH*-M!  
} ,kJ7c;:i  
>O\+9T@  
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//获得文件长度 /3aW 0/^o  
public long getFileSize() @KL&vm(F$  
{ T9V=#+8#"  
int nFileLength = -1; Bn]=T  
try{ Hnt*,C.0  
URL url = new URL(siteInfoBean.getSSiteURL()); Dq<la+VlO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Csuasi3]1d  
httpConnection.setRequestProperty("User-Agent","NetFox"); n!z!fh  
J1}\H$*X  
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int responseCode=httpConnection.getResponseCode(); o^~ZXF}  
if(responseCode>=400) 5\pS8<RJ;  
{ 7_2D4CI  
processErrorCode(responseCode); sg7h&<Xx  
return -2; //-2 represent access is error =T9h7c R  
} vIJ5iLF  
JhFn"(O  
[<53_2]~  
String sHeader; Eto"B"  
YAc:QVT87  
Sh!c]r>\Q  
for(int i=1;;i++) L4Jm8sy{  
{ l48$8Mgrr  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); *gwaW!=  
//Utility.log(in.readLine()); 44*#qLN  
sHeader=httpConnection.getHeaderFieldKey(i); 1k6asz^T  
if(sHeader!=null) 5Qq/nUR  
{ {C5:as  
if(sHeader.equals("Content-Length")) b5|*p(7[  
{ #1haq[Uv7  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ,A{Bx`o?  
break; &"%Ws{Qn]  
} 7=Muq]j2  
} h,Hr0^?  
else ,}IcQu'O  
break; f`Fj-<v  
} MOQ6&C`7q  
} k3$'K}=d  
catch(IOException e){e.printStackTrace ();} `'s_5Ek  
catch(Exception e){e.printStackTrace ();} sR9$=91`  
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 ~frsgHW  
Utility.log(nFileLength); &'/"=lK  
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return nFileLength; 5&s6(?,Eu  
} DD=X{{;D\"  
( 3B1X  
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//保存下载信息（文件指针位置） 5Hu[*  
private void write_nPos() anW['!T9{s  
{ w3(G!:  
try{ /FN:yCf  
output = new DataOutputStream(new FileOutputStream(tmpFile)); vE)N6Ss  
output.writeInt(nStartPos.length); 3q/Us0jr  
for(int i=0;i<nStartPos.length;i++) I]eeV+U8W  
{ x >ah,  
// output.writeLong(nPos); {nmu(EP  
output.writeLong(fileSplitterFetch.nStartPos); G{: B'08  
output.writeLong(fileSplitterFetch.nEndPos); $Xwk8<  
} _\d|`3RM  
output.close(); z~h?"'  
} =Oy&f:s  
catch(IOException e){e.printStackTrace ();} ?Vg~7Eu0  
catch(Exception e){e.printStackTrace ();} _5 SvZ;4  
} 7310'wc  
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//读取保存的下载信息（文件指针位置） ?-c|c_|$  
private void read_nPos() vy~6]hH  
{ %q|*}l  
try{ "J,|),Yd  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8)8~c@  
int nCount = input.readInt(); y0p=E^QM  
nStartPos = new long[nCount]; fC'u-m?!Q'  
nEndPos = new long[nCount]; *N$XQ{o  
for(int i=0;i<nStartPos.length;i++) u;9iuc`*  
{ c{Z "'t7  
nStartPos = input.readLong(); Mi.2 >  
nEndPos = input.readLong(); I?D=Q$s  
} q*lk9{>  
input.close(); P\Qvj7_  
} YMu#<ZG  
catch(IOException e){e.printStackTrace ();} c<_1o!68  
catch(Exception e){e.printStackTrace ();} h i!K-_Uy  
} *66EkCj  
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/b #w.>e  
private void processErrorCode(int nErrorCode) kI`HD
 
{ I7Kgi3  
System.err.println("Error Code : " + nErrorCode); -I{op wd  
} JYNnzgd  
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6%p6BK6  
//停止文件下载 CL2zZk{u_  
public void siteStop() ?x",VA  
{ BywEoS  
bStop = true; pHR`%2!"t  
for(int i=0;i<nStartPos.length;i++) \ R}I4'  
fileSplitterFetch.splitterStop(); $DH/  
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} *1v3x:pQ'  
} s@~3L  
//负责部分文件的抓取 `Zuo`GP*1  
**FileSplitterFetch.java Bs0~P 4^  
*/ (zsmJe  
package NetFox; aW:*!d#  
>AV
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import java.io.*; g.Ur~5r  
import java.net.*; ^kK")+K  
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public class FileSplitterFetch extends Thread { XC6|<pru  
I;jH'._k#  
br88b`L  
String sURL; //File URL P}AwE,&Q  
long nStartPos; //File Snippet Start Position JGq9RB]D$  
long nEndPos; //File Snippet End Position @8J*vY =e  
int nThreadID; //Thread's ID LT{g^g  
boolean bDownOver = false; //Downing is over X_-/j.  
boolean bStop = false; //Stop identical "d/54PKWx  
FileAccessI fileAccessI = null; //File Access interface T#rUbi>""  
&O+S[~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /b{@']  
{ #pRbRT9  
this.sURL = sURL; ~Fvz&dO  
this.nStartPos = nStart; H)TKk%`7  
this.nEndPos = nEnd; "=]'"'B:  
nThreadID = id; 0KExB{K  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )]Zdaw)X  
} 7mnO60Z8N  
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public void run() "?aE3$/  
{ W{JR%Sq$  
while(nStartPos < nEndPos && !bStop) clqFV   
{ q) 5s'(  

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try{ 2|!js
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URL url = new URL(sURL); dn~k_J=p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W"/,<xHuh  
httpConnection.setRequestProperty("User-Agent","NetFox"); #lFsgb  
String sProperty = "bytes="+nStartPos+"-";  1^hG}#6_  
httpConnection.setRequestProperty("RANGE",sProperty); FFwu$S6e  
Utility.log(sProperty); S5m.oHJI*  
%[*_-%  
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InputStream input = httpConnection.getInputStream();  wD  
//logResponseHead(httpConnection);  [K
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}rVLWt
 
byte[] b = new byte[1024]; cP
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int nRead; l}S96B  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) sFk{Tv@Yz  
{ 'u PI~l`g  
nStartPos += fileAccessI.write(b,0,nRead); uG.`  
//if(nThreadID == 1) @B+8' b$9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y\6C9%.  
} G?s
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Utility.log("Thread " + nThreadID + " is over!"); &_QD1 TT  
bDownOver = true; sAX4giaLD  
//nPos = fileAccessI.write (b,0,nRead); ]*DIn1C^  
} &z\?A2Mw%  
catch(Exception e){e.printStackTrace ();} 2sBYy 8.r  
} B_c-@kl   
} AA|G&&1y  
9Z2aFW9  
=;8q`  
//打印回应的头信息 H-& ktQWK3  
public void logResponseHead(HttpURLConnection con) xjDaA U,  
{ q/7T-"q/G  
for(int i=1;;i++) L{f0r!d|  
{ Ov:U3P?%  
String header=con.getHeaderFieldKey(i); 7'{%dj
L  
if(header!=null) 3gCP?%R  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Kv5 !cll5  
Utility.log(header+" : "+con.getHeaderField(header)); 6XhS g0s  
else X=Y>9  
break; ]nS9taEA   
} O St~P^1  
} #R=6$  
jfR!M07|  
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public void splitterStop() cpq0'x\  
{ ]x_
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bStop = true; oe_,q&e  
} NUY sQO)  
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} >y@3`u]  
(a|Wq{`[  
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/* "X1{*  
**FileAccess.java /h!iLun7I  
*//文件访问(定位，写) v Dph}Z  
package NetFox; bsWDjV~  
import java.io.*; n QOLR?%  
M)nf(jw#G  
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public class FileAccessI implements Serializable{ FefS]G  
{M0pq3SL*t  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 uc;,JX!bN  
RandomAccessFile oSavedFile; }PzYt~Z`@  
long nPos; =H^^AG\}  
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public FileAccessI() throws IOException yc$8X sns  
{ ;fY)7 '  
this("",0); '$CJZ`nt  
} {uO2m*JrI  
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JA?P jo  
public FileAccessI(String sName,long nPos) throws IOException WB|SXto%4D  
{ 9fb"R"(M  
oSavedFile = new RandomAccessFile(sName,"rw"); ~F]If\b  
this.nPos = nPos; 0>?78QL9<  
oSavedFile.seek(nPos); ld23^r  
} u/74E0$S  
+(2mHS0_
a  
"IsDL^)A9  
public synchronized int write(byte[] b,int nStart,int nLen) NB/ wJ3 F  
{ T$xY]hqr  
int n = -1; ki_Py5  
try{ }~o>H a;  
oSavedFile.write(b,nStart,nLen); h3L{zOff  
n = nLen; kF*^" Cn  
}
Kd,7x'h`E  
catch(IOException e) BBm;QOBU  
{ r \]iw v  
e.printStackTrace (); wkZ}o,{*:  
} 6t6#<ts  
!Zf)N_k  
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return n; KbF,jm5  
} d\aU rsPn  
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} 4qEe
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/* (%EhkTb  
**SiteInfoBean.java IE9A _u*  
*/ xk5
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package NetFox; /7<l`RSr  
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 H@,(  
public class SiteInfoBean { (f|3(u'e?  
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GKKf#r74  
private String sSiteURL; //Site's URL ^cF_z}Zi+  
private String sFilePath; //Saved File's Path =h2zIcj  
private String sFileName; //Saved File's Name "S@%d(lg  
private int nSplitter; //Count of Splited Downloading File
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U_c.Z{lC4  
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public SiteInfoBean() :X;'37o#q  
{//nSplitter的缺省值为5 hpJi,4r.d  
//default value of nSplitter is 5 YTpO4bX  
this("","","",5); <$'OSN`!  
} GoNX\^A  
,0=:06l  
"+V.Yue`R  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @'EU\Y\l  
{ n +z5;'my  
sSiteURL= sURL; vrD]o1F  
sFilePath = sPath; $fA%_T_P'P  
sFileName = sName; bO%bMZWB!y  
this.nSplitter = nSpiltter; RcH",*U  
f?1?$Sp/W  
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} rOu7r4  
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|};P"&  
public String getSSiteURL() ;'r} D!8w/  
{ cmv&!Egd  
return sSiteURL; 8D U|j-I8  
} 'J&$L c  
n`krK"Ii  
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public void setSSiteURL(String value) D"m]`H  
{ @m[r0i0J"  
sSiteURL = value; 195m0'zda  
} N%\!eHxy  
2\M^_x$N  
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public String getSFilePath() uMToVk`Uv  
{ J ;=~QYn[  
return sFilePath; W7lR54%|  
} ~I%m[fQ S  
['~B&  
ee.#Vhz  
public void setSFilePath(String value) !>{`o/dZ  
{ ~4\J}Kn  
sFilePath = value; 2WRa@;Tj  
} .>0j<|~  
,=tPh4>  
`)5E_E3  
public String getSFileName() *1fq:--  
{ #%xzy@`  
return sFileName; EencMi7J  
} c-L1 Bkw  
B6&;nU>;  
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public void setSFileName(String value) 5 #)5Z8`X  
{ B'OUT2cgB  
sFileName = value; ruG5~dm>  
} i"~J -{d}  
 ]CD  
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public int getNSplitter() ^#T@NN0T  
{ ?H\K];  
return nSplitter; @-9I<)Z/2  
} "|yuP1;L  
0HA`  

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public void setNSplitter(int nCount) g?.ls{H  
{ 3?F*|E_  
nSplitter = nCount; "#d>3M_  
} RCSG.*%%I  
} 0>?%{Xy  
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2HNKq<  
/* (,wIbwa  
**Utility.java ?8AchbK;N  
*/ @7Oqp-  
package NetFox; 7cTDbc!E-  
!=7(3<?  
]_6w(>A@3#  
public class Utility { gJEm  
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' XJ>;",[  
public Utility() SW!lSIk  
{ ToWiXH)4
 
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}  
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} RjC3wO::  
'O%itCy)  
//线程睡眠 &DQyJJ`k  
public static void sleep(int nSecond) .v?x>iV  
{ v803@9@  
try{ WZ\bm$  
Thread.sleep(nSecond); A dNQS  
} m5c?A+@fZ  
catch(Exception e) %~eIx=s  
{ TUw+A6u:p  
e.printStackTrace (); -?_#Yttu  
} AI{Tw>hZ  
} Ah5`
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-][~_Hd{  
//日志 SvZ~xTit  
public static void log(String sMsg) 3K2B7loD)~  
{ y:t@X
~  
System.err.println(sMsg); N~rA/B]T  
} rucgav  
@ev"{dY  
I$.HG]  
public static void log(int sMsg) w$Zi'+&*  
{ v
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System.err.println(sMsg); c2Q KI~\x  
} q~esxp  
} 1:!_AU?  
6#[  
]S@
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/* zSy^vM;6zf  
**TestMethod.java V iY-&q'  
*/ `1}WQS  
package NetFox; rC`pTN  
CD}::7$  
U"nk AW  
public class TestMethod { ,%)O/{p_  
&8p]yo2zO  
_yH{LUIj  
public TestMethod() =E6ND8l@2  
{ ///xx/weblogic60b2_win.exe ]Sj<1tx7f  
try{ yx
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); PIk2mX/D_6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); in-|",O`Z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); tu5g> qb  
fileFetch.start(); " pg5w  
} > 2)@(f~g  
catch(Exception e){e.printStackTrace ();} 9:DT+^BB  
3K;V3pJ].  
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} 73Zx`00  
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public static void main(String[] args) GkwdBy+  
{
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new TestMethod(); b
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} z):LF<  
} e}f#dR+(  
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