http断点续传简单实现（java)

/* kV!1k<f  
**SiteFileFetch.java 9JJ6$cLF  
*/ #MiO4zXgd  
package NetFox; 8+32hg@^F  
import java.io.*; }ov>b2H#<  
import java.net.*; y6MkaHW[m  
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public class SiteFileFetch extends Thread { +
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SiteInfoBean siteInfoBean = null; //文件信息Bean
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long[] nStartPos; //开始位置 CoWT  
long[] nEndPos; //结束位置 &SPr#OkW  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4E1j0ARQQ  
long nFileLength; //文件长度 T eu.i  
boolean bFirst = true; //是否第一次取文件 9F~5Ht  
boolean bStop = false; //停止标志 dP]Z:  
File tmpFile; //文件下载的临时信息 K5??WB63B  
DataOutputStream output; //输出到文件的输出流 eiRVw5g  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -_]Ceq/  
public SiteFileFetch(SiteInfoBean bean) throws IOException SbsdunW+?  
{ Rd5pLrr[0)  
siteInfoBean = bean; ^$RpP+d  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); VD =f 'D  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); P\z1fscnK  
if(tmpFile.exists ()) =
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{ {BJH}vV1)  
bFirst = false; #Pg?T%('`  
read_nPos(); h53G$Ol
.  
} !d[]Qt%mA  
else rhGB l`(B  
{ t^%)d7$  
nStartPos = new long[bean.getNSplitter()]; s:z  
nEndPos = new long[bean.getNSplitter()]; _)4zm  
} C]ax}P>BQ  
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} RK)ikLgp  
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public void run() I7t}$S6  
{ Lw?>1rTT/  
//获得文件长度 _p9 _Pg8  
//分割文件   &._Mh  
//实例FileSplitterFetch >N}+O<Fc  
//启动FileSplitterFetch线程 <xH! Yskc  
//等待子线程返回 s9fEx-!y  
try{ C/ ]Bx  
if(bFirst) ;$qc@)Uwp  
{ ?}u][akM  
nFileLength = getFileSize(); [d>2F  
if(nFileLength == -1) {e0aH `me  
{ !thFayq  
System.err.println("File Length is not known!"); Z0wH%
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} U2\k7I  
else if(nFileLength == -2) H;Gs0Qi;  
{ 2_Cp}Pj  
System.err.println("File is not access!"); Lg2PP#r  
}
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else &hZ6CV{  
{ zhyf}Ta'  
for(int i=0;i<nStartPos.length;i++) 
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{ ~i>'3j0@k  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |]-~yYqP3  
} eQqCRXx  
for(int i=0;i<nEndPos.length-1;i++) |t#s h  
{ &rc r>-  
nEndPos = nStartPos[i+1]; uD ;T   
} eq9qE^[Z&  
nEndPos[nEndPos.length-1] = nFileLength; ZOx;]D"s  
} UM0#S}  
} 5D3&6DCH  
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-:b<~S[  
//启动子线程 2t=&h|6EW  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?4Rq +  
for(int i=0;i<nStartPos.length;i++) LVL#qNIu  
{ : >$v@d  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (?.h<v1}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), EvA8<o  
nStartPos,nEndPos,i); ,.Lo)[(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PX?^v8wlqL  
fileSplitterFetch.start(); F0k
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} +5kQ;D{+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *$mb~k^R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :U @L$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |UcF%VNnz1  
nEndPos = " + nFileLength); 7a.iT-*  
// fileSplitterFetch[nPos.length-1].start(); Vu<mOuh
 
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//等待子线程结束 cn9=wm\\  
//int count = 0; E6-~  
//是否结束while循环 &G3$q,`H  
boolean breakWhile = false; }UG<_bE|  
.ffr2\'*  
Ow-;WO_HQ  
while(!bStop) 4!?4Tc!X  
{ a4q02 cV  
write_nPos(); &kH7_Lz  
Utility.sleep(500); =v{
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breakWhile = true; -^rdB6O6j  
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for(int i=0;i<nStartPos.length;i++) |CBJ8],mT  
{ KF`m
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if(!fileSplitterFetch.bDownOver) 8yuTT^  
{ Imo?)dYK  
breakWhile = false; XhOg>  
break; mt-t8~A  
} =]<X6!0mR  
} !~-@sq  
if(breakWhile) ^)3=WD'!  
break; DuC_uNJ  
~UsE"5  
,JJ1sf2A  
//count++; )_Iu7b  
//if(count>4) ;y>}LGG  
// siteStop(); _Vr}ipx-k  
} ,awkL :  
Jb8%A@Z+  
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System.err.println("文件下载结束！"); "m}N hoD4  
} op_ 1J;RF  
catch(Exception e){e.printStackTrace ();} 2W63/kRbU  
} Ye[Fu/0  
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#}
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//获得文件长度 8: VRq  
public long getFileSize() ~jC$C2A0  
{ N,ZmGzNP)  
int nFileLength = -1; Mo4igP  
try{ m
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URL url = new URL(siteInfoBean.getSSiteURL()); u>2opI
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yJ8_<A  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9
}d^ll&  
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int responseCode=httpConnection.getResponseCode(); _wZr`E)  
if(responseCode>=400) Wtflw>-  
{ @^b>S6d"  
processErrorCode(responseCode); u4[rA2Bf8E  
return -2; //-2 represent access is error YXGxE&!  
} 1(Lq9hs`  
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+a'nP=e&  
String sHeader; $,1KD3;+]  
nA+gqY6 6|  
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for(int i=1;;i++) In}~bNv?  
{ ;O({|mpS\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); BM02k\%  
//Utility.log(in.readLine()); =>xyJ->R  
sHeader=httpConnection.getHeaderFieldKey(i); d s}E|Q  
if(sHeader!=null) ,WS{O6O7  
{ l_T5KV  
if(sHeader.equals("Content-Length")) ban;HGGNG{  
{ R!:F
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); v&"sTcS|  
break; tSunO-\y  
} HU-#xK  
} :2;c@ uj  
else u9ue>I/  
break; PkF'#W%  
} /I0}(;^y  
} %nj{eT  
catch(IOException e){e.printStackTrace ();} ->@iw!5xu  
catch(Exception e){e.printStackTrace ();} eXtlqU$  
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Utility.log(nFileLength); W0# VDe]>  
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return nFileLength; q&: t$tSS  
} !f#[4Xw  
(KphAA8  
*Di ;Gf@  
//保存下载信息（文件指针位置） dca?(B!'6  
private void write_nPos() D(">bR)1  
{ Jrx]/CM  
try{ j.29nJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); gCW {$d1=  
output.writeInt(nStartPos.length); sW@_q8lG  
for(int i=0;i<nStartPos.length;i++) xGK"`\V  
{ >]?!9@#IH  
// output.writeLong(nPos); ~4ysg[`  
output.writeLong(fileSplitterFetch.nStartPos); sq}uq![?
M  
output.writeLong(fileSplitterFetch.nEndPos); uBo~PiJ2"  
} 2?c%<_jPA  
output.close(); ;VPYWss  
} fZ  pUnc  
catch(IOException e){e.printStackTrace ();} B..> *Xb  
catch(Exception e){e.printStackTrace ();} *6]_ 6xO  
} [vcSt5R=  
;)!);q+  
4,7W*mr3(  
//读取保存的下载信息（文件指针位置） :ZU
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private void read_nPos() tL S$D-  
{ ZrDr/Q~  
try{ #80r?,q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); A
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int nCount = input.readInt(); ||rZ
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nStartPos = new long[nCount]; r-c1_ [Q#  
nEndPos = new long[nCount]; [J43]  
for(int i=0;i<nStartPos.length;i++) Zex`n:Wl?j  
{ 4tFnZ2x  
nStartPos = input.readLong(); >W=
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nEndPos = input.readLong(); EZ)GW%Bm2  
} Ly`FU)  
input.close(); 8,?*eYNjb  
} v'u}%FC  
catch(IOException e){e.printStackTrace ();} Cq<k(TKAX  
catch(Exception e){e.printStackTrace ();} S(hT3MAW  
} O|0}m  
-!:h]
 
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private void processErrorCode(int nErrorCode) 1IZTo!xi  
{ BPC>  
System.err.println("Error Code : " + nErrorCode); -y)g}D%  
} OG2&=~hOz-  
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//停止文件下载 @i@f@.t  
public void siteStop() 8
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{ 3>buZ6vh  
bStop = true; 4>te>[  
for(int i=0;i<nStartPos.length;i++) j79$/ Ol  
fileSplitterFetch.splitterStop(); C: a</Sl  
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} hrTl:\  
} to;cF6X  
//负责部分文件的抓取 
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**FileSplitterFetch.java ,IQ%7*f;O_  
*/ txemu*  
package NetFox; %51HJB}C]  
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import java.io.*; )r:gDd#/X  
import java.net.*; ?F@X>zR2  
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public class FileSplitterFetch extends Thread { RV, cQ K  
MF.$E?_R  
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String sURL; //File URL ;F\sMf{  
long nStartPos; //File Snippet Start Position Pxe7 \e  
long nEndPos; //File Snippet End Position LkUi^1((e  
int nThreadID; //Thread's ID yI_MYL[  
boolean bDownOver = false; //Downing is over ]d50J@W c  
boolean bStop = false; //Stop identical (,2U?p  
FileAccessI fileAccessI = null; //File Access interface _}:#T8h  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException t%]b`ad  
{ F=~LVaF/_  
this.sURL = sURL; g9:V00^<  
this.nStartPos = nStart; .0#{?R,  
this.nEndPos = nEnd; Yjp*T:6  
nThreadID = id; k= oCpXq^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 s,;L6nX"  
} WEk3 4crk  
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public void run() gL6.,4q+1  
{ rJ fO/WK  
while(nStartPos < nEndPos && !bStop) (j884bu  
{ y_N h5  
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try{ ?/^x)Nm  
URL url = new URL(sURL); C+Pw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lsRW.h,  
httpConnection.setRequestProperty("User-Agent","NetFox"); S]}W+BF3  
String sProperty = "bytes="+nStartPos+"-"; 2U`g[1  
httpConnection.setRequestProperty("RANGE",sProperty); /7p1y v  
Utility.log(sProperty); bKP@-<:]  
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InputStream input = httpConnection.getInputStream(); Ai.^~#%X  
//logResponseHead(httpConnection); fIm=^}?fwK  
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byte[] b = new byte[1024]; QDJe:\n  
int nRead; yh"48@L'D  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
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{ ]{PJ  
nStartPos += fileAccessI.write(b,0,nRead); hR%2[lBn!]  
//if(nThreadID == 1) #i}:CI>2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z)XIA)i6  
} m005*>IY  
/faP@Q3kR  
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Utility.log("Thread " + nThreadID + " is over!"); &U0Y#11Cx  
bDownOver = true; 5qQ\H}  
//nPos = fileAccessI.write (b,0,nRead); F
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} -%6Y&_5VK  
catch(Exception e){e.printStackTrace ();} E_j=v \  
} D|E,9
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} W`` 
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//打印回应的头信息 uEcK0>xp  
public void logResponseHead(HttpURLConnection con) "|W``&pM  
{ i4r8146D[  
for(int i=1;;i++) UA}N  
{ |t&gyj  
String header=con.getHeaderFieldKey(i); vFgX]&bE  
if(header!=null) '"fZGz?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D}A>`6W<  
Utility.log(header+" : "+con.getHeaderField(header)); }@Ou]o  
else <CY<-H  
break; V}+Ui]ie|I  
} #JW~&;  
} (GXFPEH8  
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public void splitterStop() [pYjH+<  
{ px=r~8M9}  
bStop = true; %6HJM| {H  
} 7/GL@H  
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} zTS#o#`!\  
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/* /dq(Z"O_  
**FileAccess.java b 3i34,  
*//文件访问(定位，写) #>\%7b59>  
package NetFox; T@\%h8@~]  
import java.io.*; I18<brZJ  
tA]Y=U+Q  
A,
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public class FileAccessI implements Serializable{ +o^sm'$  
%hH@< <b(s  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 $V2.@X  
RandomAccessFile oSavedFile; h;S?  
long nPos; Kuy0Ci  
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public FileAccessI() throws IOException 2L|)uCb  
{ LGPPyKNx  
this("",0); LQ3J$N  
} ^muPjM+D  
|tqYRWn0  
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public FileAccessI(String sName,long nPos) throws IOException ewOR
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{ 4+'d">+|  
oSavedFile = new RandomAccessFile(sName,"rw"); u:GDM  
this.nPos = nPos; 6R+EG{`  
oSavedFile.seek(nPos); wTkcR^  
} HA0Rv#p  
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YH/3N(],  
public synchronized int write(byte[] b,int nStart,int nLen) y(h"0A1lW  
{ +w'He9n  
int n = -1; 't<hhjPqY  
try{ Yo;Mexo!  
oSavedFile.write(b,nStart,nLen); l~c# X3E  
n = nLen; U t'r^  
} ]B>g~t5J  
catch(IOException e) ERZWK  
{ d<+@cf_9  
e.printStackTrace (); {&d )O  
} `;\~$^sj}  
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return n; b?deZ2"L#  
} .U9A\$  
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} P2>Y0"bY  
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3~6,fTMz{  
/* N,~"8YSo  
**SiteInfoBean.java ?2i\ERG?  
*/ j#[%-nOT  
package NetFox; z((9vi W  
)h,
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public class SiteInfoBean { 3}25=%;[  
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private String sSiteURL; //Site's URL fZF.eRP'  
private String sFilePath; //Saved File's Path `(Ij@84  
private String sFileName; //Saved File's Name 7zEpuw  
private int nSplitter; //Count of Splited Downloading File NQqq\h  
0FG|s#Ig  
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public SiteInfoBean() h(M
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{//nSplitter的缺省值为5 MR-cOPn  
//default value of nSplitter is 5 =VOl *  
this("","","",5); c?XqSK`',Z  
} T,SCK^  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _ pKWDMB$z  
{ m.DC  
sSiteURL= sURL; TB(!*t  
sFilePath = sPath; VaLl$w  
sFileName = sName; f%cbBx^;  
this.nSplitter = nSpiltter; IM9P5?kJ ?  
9i*Xd$ G  
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} =V*4&OU  
"'\f?A
9  
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public String getSSiteURL() *^t7?f[  
{ vg ^&j0  
return sSiteURL; y&{ Z"+B5  
} d0CFMy6  
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r,-9]?i  
public void setSSiteURL(String value) %5|DdpES  
{ 'W]oQLD^R  
sSiteURL = value; N_qKIc_R  
} @!:_r5R~N  
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&7m)K>E27  
public String getSFilePath() bk{.9nz2  
{ %eDJ]\*^X  
return sFilePath; Y%A KN  
} g"o),$tm  
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public void setSFilePath(String value) KuohUH+  
{ .,7ZDO9{  
sFilePath = value; tpP2dg9dF  
} [V_?`M  
JHIXTy__  
3PU'd^  
public String getSFileName() 'p:L"L}Q?  
{ aq<QKnU  
return sFileName; hDc)\vzr  
} [tY+P7j9)  
GYM6 `  
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public void setSFileName(String value) k>;a5'S  
{ z3>oUq{  
sFileName = value; /'g"Ys?3  
} y.m;4((  
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public int getNSplitter() I'%(f@u~  
{ D"RxI)"HP  
return nSplitter; Vuu_Sd  
} @mu2,%  
{P>%l\?  
XOi[[G}  
public void setNSplitter(int nCount) =gb(<`{>  
{ [J6b5  
nSplitter = nCount; 6ISDY>p  
} L.M|o  
} BL Q&VI4  
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;%tu;  
/* &}/h[v_#'  
**Utility.java oy!Dm4F  
*/ %/(>>*}Kw|  
package NetFox; \r+8}8  
|~I-  
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public class Utility { {f }4l  
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public Utility() <dA1n:3o  
{ 7/$s!pV  
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rt7]~W-  
} d3|oKP6  
r=3knCEWK  
//线程睡眠 Q]]5\C.  
public static void sleep(int nSecond) I N'a5&..  
{ J}vxK H#=  
try{ =P.m5e<  
Thread.sleep(nSecond); \dIQhF%%2  
} r$Z_Kwe.|&  
catch(Exception e) _^)<d$R<  
{ H!NyM}jsr  
e.printStackTrace (); E-_Q3^
  
} /kY|PY  
} &@MiR8  
c#6g[TE@  
//日志 *1[v08?!  
public static void log(String sMsg) `/z6Q"  
{ '!6Py1i  
System.err.println(sMsg); L)LW5%.6  
} CrIt h/Z  
'l}T_7g  

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public static void log(int sMsg)  `=h`:`  
{ _@47h86Q  
System.err.println(sMsg); $"/xi `  
} 3+EAMn  
} bf3Njma%  
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/* 1E*No1  
**TestMethod.java %EooGHGF?  
*/ ~KufSt*  
package NetFox; .#] V5g,  
R""P01IZH  
V~uH)IMkh7  
public class TestMethod { ]$>O--  
i:ZL0nH-  
jB17]OCN  
public TestMethod() SOI$Mx  
{ ///xx/weblogic60b2_win.exe %dMP}k/  
try{ #iOoi9(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); BF_R8H,<%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); RG)!v6
  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @KhDQ0v]5  
fileFetch.start(); aJC,  
} >*PZ&"}M  
catch(Exception e){e.printStackTrace ();} \+cU}  
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} Qw{LD+r(  
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public static void main(String[] args) E-\<,=bh  
{ -];/*nl  
new TestMethod(); fq.ui3lP)  
} 4X@ <PX5  
} 0z2A!ap  
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