http断点续传简单实现（java)

/* )%bY2 pk  
**SiteFileFetch.java P`y 0FKS  
*/ *?!A  
package NetFox; Z`yW2ON$'  
import java.io.*; cpQhg-LY|  
import java.net.*; #4{9l SbU  
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public class SiteFileFetch extends Thread { r~sQdf  
.!Os'Y9[,  
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SiteInfoBean siteInfoBean = null; //文件信息Bean j6&7tK,  
long[] nStartPos; //开始位置 i]IZ0.?Y  
long[] nEndPos; //结束位置 IfpFsq:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Hv .C5mo  
long nFileLength; //文件长度 -MItZ  
boolean bFirst = true; //是否第一次取文件 22"/|S  
boolean bStop = false; //停止标志 nX-%qc"  
File tmpFile; //文件下载的临时信息 
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DataOutputStream output; //输出到文件的输出流 ]F1ZeAh5  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &g
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public SiteFileFetch(SiteInfoBean bean) throws IOException @(s"5
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{ 7VKTI:5y  
siteInfoBean = bean; qY%{c-aMA  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ompkDl\E  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); AV^Sla7|_  
if(tmpFile.exists ()) zIgD R  
{ "ju0S&  
bFirst = false; t"]~e"  
read_nPos(); $_NP4V8|z/  
} 9|RR;k[  
else o;2QZ"v  
{ FT.;}!"l  
nStartPos = new long[bean.getNSplitter()]; Irnfr\l.  
nEndPos = new long[bean.getNSplitter()]; Ae 3:"  
} *WpDavovyB  
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} o$-!E(p  
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public void run() 7;;HP`vY  
{ p2:>m\  
//获得文件长度 +>wBGVvS  
//分割文件 =vZF/r  
//实例FileSplitterFetch sHQ82uX  
//启动FileSplitterFetch线程 :gJ?3LwTf  
//等待子线程返回 d~U}IMj  
try{ 8Cw+<A*  
if(bFirst) :AM5EO  
{ >l3iAy!sZ  
nFileLength = getFileSize(); QZs ]'*=#  
if(nFileLength == -1) =~f\m:Y  
{ mjtmN0^SR  
System.err.println("File Length is not known!"); 1SGLA"r  
}  jA}b=c  
else if(nFileLength == -2) p\ }Ep  
{ J@vL,C)E6  
System.err.println("File is not access!"); [R~`6  
} kZ>Xl- LV  
else ?' :v):J}  
{ jJK`+J,i}X  
for(int i=0;i<nStartPos.length;i++) 2/W5E-tn  
{ g VPtd[r  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \6)]!$F6:  
} lEWF~L5=:  
for(int i=0;i<nEndPos.length-1;i++) t/57LjV  
{ [,)G\  
nEndPos = nStartPos[i+1]; |r%NMw #y  
} G (o9*m1  
nEndPos[nEndPos.length-1] = nFileLength; ~0 Ifg_G  
} "A]Xe[oS  
} -E(0}\  
[
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!F|#TETrt  
//启动子线程  UqwU3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]9P2v X   
for(int i=0;i<nStartPos.length;i++) p-Jp/*R5  
{ Sr#\5UDS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T{:~v+I=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 1XpG7  
nStartPos,nEndPos,i); * ",/7(  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :yi?<  
fileSplitterFetch.start(); A 6IrA/b  
} LN0pC}F  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [^S(SPL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); N|@jHxy  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",  B8~JUGD  
nEndPos = " + nFileLength); m0Geq.  
// fileSplitterFetch[nPos.length-1].start(); [`4  
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|W#(+m  
//等待子线程结束 ~~\C.6c#  
//int count = 0; 4'wbtE|  
//是否结束while循环 B{ Ab#  
boolean breakWhile = false; 5(=5GkE)>  
%;eD.If}  
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while(!bStop) OAauD$Hh  
{ g2;lEW  
write_nPos(); #PkZi(k hv  
Utility.sleep(500); T!7B0_  
breakWhile = true; ;l %$-/%  
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for(int i=0;i<nStartPos.length;i++) ;=p3L<~c`K  
{ m{;j r<  
if(!fileSplitterFetch.bDownOver) hp1+9vEN  
{ -3K01p  
breakWhile = false; RY
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break; u*T(n s l  
} O joa3  
} R4y]<8}  
if(breakWhile) n_4 r'w  
break; vSu dT  
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//count++; `Gj(>z*  
//if(count>4) PjD9D.  
// siteStop(); q6,z 1A"  
} n
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System.err.println("文件下载结束！"); lA pZC6Iwk  
} YF)]B|I  
catch(Exception e){e.printStackTrace ();} >J5C.hx  
} nwp(% fBo  
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&7i&"TNptP  
//获得文件长度 /5<=m:  
public long getFileSize() EV?U !O  
{ g)5mr:\  
int nFileLength = -1; S,j. ?u*!  
try{ @c-  
URL url = new URL(siteInfoBean.getSSiteURL()); W6Mq:?+D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $~S~pvT  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y hQ)M5  
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int responseCode=httpConnection.getResponseCode(); _1NK9dp:  
if(responseCode>=400) ESNI$[`  
{ [ /YuI@C,@  
processErrorCode(responseCode); D#G%WT/"  
return -2; //-2 represent access is error WR3,woo  
} zs~Tu  
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String sHeader; <n4`#d  
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for(int i=1;;i++) 59O-"Sc[  
{ :{
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); mUbm3JIjJ  
//Utility.log(in.readLine()); 00.x*v  
sHeader=httpConnection.getHeaderFieldKey(i); +4.s4&f)  
if(sHeader!=null) +]s,VSL5`  
{ p_h/hTi  
if(sHeader.equals("Content-Length")) {$,\Qg  
{ a8f#q]TyQ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QJ3#~GYNr  
break; ~PI2G9  
} {YgU23;q  
} ~x
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else Vw1>d+<~-)  
break; @^<odmM  
} %+H_V1F  
} @QQ%09*  
catch(IOException e){e.printStackTrace ();} V9
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catch(Exception e){e.printStackTrace ();} &h0LWPl  
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Utility.log(nFileLength);  yf
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return nFileLength; ryVYY>*(K  
} |n/;x$Cb  
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taE p   
//保存下载信息（文件指针位置） ]>1Mq,!  
private void write_nPos() >$JE!.p%o  
{ CefFUqo4  
try{ Hz.i$L0}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); "[N2qJ}p  
output.writeInt(nStartPos.length); &VGV0K3Dp  
for(int i=0;i<nStartPos.length;i++) :)~l3:O  
{ 9wYm(7M6  
// output.writeLong(nPos); ?6CLUu|7n  
output.writeLong(fileSplitterFetch.nStartPos); '#7k9\  
output.writeLong(fileSplitterFetch.nEndPos); %JM$]  
} 0vq
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output.close(); ubM1Qr  
} W3,r@mi^s7  
catch(IOException e){e.printStackTrace ();} \J+a7N8m,  
catch(Exception e){e.printStackTrace ();} .dU91> ~Ov  
} _LHbP=B  

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//读取保存的下载信息（文件指针位置） l zFiZx  
private void read_nPos()
<  o?ua}  
{ r
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try{ V *@q< rQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); R4
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int nCount = input.readInt(); a51(ySC}<s  
nStartPos = new long[nCount]; 3N_
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nEndPos = new long[nCount]; uOv<*Jld*  
for(int i=0;i<nStartPos.length;i++) VeWh9:"bJ  
{ h>`[p
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nStartPos = input.readLong(); T \/^4N`  
nEndPos = input.readLong(); {'{}@CuA2  
} 6]1RxrAV  
input.close(); Q#%LIkeq  
} 9K&$8aD  
catch(IOException e){e.printStackTrace ();} E{Wn&?i>A  
catch(Exception e){e.printStackTrace ();} XZOBK^,5^B  
} >GIQT?O6  
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private void processErrorCode(int nErrorCode) z -?\b^  
{ U<=TAWZ@  
System.err.println("Error Code : " + nErrorCode); zu}uW,XH-  
} s]m]b#1!r  
rPB Ju0D"  
usc/DQ1  
//停止文件下载 [\ku,yd%0  
public void siteStop() a0ms9%Y;Q[  
{ 1Lf -  
bStop = true; .Yk}iHcW.  
for(int i=0;i<nStartPos.length;i++) bmHj)^v5]  
fileSplitterFetch.splitterStop(); dU-:#QV6  
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} ~[!Tpq5  
} s1OSuSL>  
//负责部分文件的抓取 &DQ_qO
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**FileSplitterFetch.java `V/kM0A5  
*/ @w33u^  
package NetFox; p!E*ANwX  
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import java.io.*; Mprn7=I{Tg  
import java.net.*; "X<V>q$0~c  
c CjN8<  
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public class FileSplitterFetch extends Thread { 0]ai*\,W7~  
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String sURL; //File URL tv-SX=T  
long nStartPos; //File Snippet Start Position  2X`t&zg  
long nEndPos; //File Snippet End Position &OvA[<qT  
int nThreadID; //Thread's ID oVl:g:K40  
boolean bDownOver = false; //Downing is over ht\_YiDg3  
boolean bStop = false; //Stop identical UnDX .W*2  
FileAccessI fileAccessI = null; //File Access interface B8wGWZ@  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "
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{ C\[:{d  
this.sURL = sURL; fG?a"6~  
this.nStartPos = nStart; uKY1AC__  
this.nEndPos = nEnd; Ct(^nn$A  
nThreadID = id; W T @XHwt  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 AO-~dV  
} 8VpmcGvc3  
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public void run() ^S|}<6~6b  
{ TPj,
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while(nStartPos < nEndPos && !bStop) OgK' ~j  
{ X~*/~f  
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try{ Ea[SS@'R  
URL url = new URL(sURL); dF&@q,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &?j\=%  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1Fsa}UK  
String sProperty = "bytes="+nStartPos+"-"; 'v(b^x<ZS  
httpConnection.setRequestProperty("RANGE",sProperty); z+c8G  
Utility.log(sProperty); ihct~y-9W  
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InputStream input = httpConnection.getInputStream();  ;t/KF"
  
//logResponseHead(httpConnection); T0o0_R  
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byte[] b = new byte[1024]; /.UISArH  
int nRead; }+:X=@Z@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *y~~~ 'J/  
{ 2p*!up(  
nStartPos += fileAccessI.write(b,0,nRead); B;<zA' 1  
//if(nThreadID == 1) KO))2GET  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F:Yp1Wrb<  
} iML?`%/vN  
z>*\nomOn=  
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Utility.log("Thread " + nThreadID + " is over!"); )'/xNR  
bDownOver = true; rj29$d?Y9  
//nPos = fileAccessI.write (b,0,nRead); T|--ZRYn  
} OFZo"XtF  
catch(Exception e){e.printStackTrace ();} z|<?=c2P  
} )SaMfP1=v  
} Nm#[A4  
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//打印回应的头信息 5_rx$avm  
public void logResponseHead(HttpURLConnection con) b~
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{ nKch:g  
for(int i=1;;i++) 8&y#LeM1TT  
{ Go7 oj'"  
String header=con.getHeaderFieldKey(i); 5QG?*Z~?7  
if(header!=null) #a 4X*X.8c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gS!zaD7Nr  
Utility.log(header+" : "+con.getHeaderField(header)); xE6hE'rh.O  
else T?*f}J  
break; |cl*wFm|3  
} r_Pi)MPc  
} 50Ov>(f@7  
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public void splitterStop() *dxE (dP  
{ :d|~k  
bStop = true; N@I=X-7nh|  
} 5M#LO@U  
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} =F46v{la  
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:CP,DO
 
/* B|r'
  
**FileAccess.java wB"`lY  
*//文件访问(定位，写) X?'pcYSL  
package NetFox; [G"Va_A8  
import java.io.*; !9_'_8  
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public class FileAccessI implements Serializable{ 4-oaq'//BT  
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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 dQy K4T  
RandomAccessFile oSavedFile; s13
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long nPos; -0P9|;h5  
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public FileAccessI() throws IOException 9A *gW j  
{ $ByP 9=|  
this("",0); XJ7pX1nf  
} iWIq~t*,H]  
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public FileAccessI(String sName,long nPos) throws IOException ~JO.h$1C  
{ -B?cF9  
oSavedFile = new RandomAccessFile(sName,"rw"); S q{@4F}d  
this.nPos = nPos; e0hY   
oSavedFile.seek(nPos); /O~Np|~v  
} } 
|  
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public synchronized int write(byte[] b,int nStart,int nLen) b7B|$T,  
{ ',/2J0_  
int n = -1; M{4XNE]m  
try{ 8[D"  
oSavedFile.write(b,nStart,nLen); x_r*<?OZ  
n = nLen; lnRL^ }  
} /Q_Dd  
catch(IOException e) F<XOt3VY.  
{ GxEShSGOE  
e.printStackTrace (); ;a| ~YM2I  
} <_#2+7Qs  
bkS"]q)>  
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return n; dCeLW  
} _*MK"  
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} {Wu[e,p  
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/* ,~DV0#"  
**SiteInfoBean.java um}q@BU  
*/ Eku9u  
package NetFox; ?)186dp  
cvG*p||  
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public class SiteInfoBean { i;-M8Q^  
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private String sSiteURL; //Site's URL qR_>41JU"  
private String sFilePath; //Saved File's Path =*"8N-FU  
private String sFileName; //Saved File's Name S0QLM)  
private int nSplitter; //Count of Splited Downloading File -*z7`]5J  
@XXPJq;J  
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public SiteInfoBean() t ^[fu,  
{//nSplitter的缺省值为5 U||GeEd  
//default value of nSplitter is 5 ".N+nM~  
this("","","",5); -5 D<zP/  
} "ayV8{m^3  
*=.~PR6W{  
)*>wa%[-q  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) WFh.oe8  
{ -(]CFnD_N  
sSiteURL= sURL; ^9:`D@Z+  
sFilePath = sPath; :C(/yg  
sFileName = sName; b%%r`j,'JE  
this.nSplitter = nSpiltter; uVCH<6Cp  
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} J\Pb/9M/  
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8c+V$rH_  
public String getSSiteURL()  }o*A>le  
{ ypx~WXFK  
return sSiteURL; ]}XDDPbZ}  
} KF_fz   
_&BK4?H@b  
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public void setSSiteURL(String value) -smN}*3[  
{ jRU:un4  
sSiteURL = value; JM|HnyI  
} 2c 0;P #ol  
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public String getSFilePath() O
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{ "Zgwe,#  
return sFilePath; S F*C'  
} ,s#~00C|  
"dX~J3$  
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public void setSFilePath(String value) I"88O4\@  
{ LBCH7@V1yR  
sFilePath = value; |VWT4*K  
} C!*!n^qA  
BqNeY<zB*  
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public String getSFileName() PlzM`g$A  
{ CW &z?Bra  
return sFileName; Bdt6 w(`^  
} `|ie#L(:7/  
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public void setSFileName(String value) 2e1KF=N+  
{ -+rzc&h  
sFileName = value; wsWFD xR  
} $ZBYOA  
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public int getNSplitter() %lHH
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{ \;X7DK2  
return nSplitter; Gaix6@X6'  
} '>"{yi-  
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public void setNSplitter(int nCount) 0kkDlWkzo  
{ f jx`|MJ  
nSplitter = nCount; $d?W1D<A  
}
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} ,;`f* #  
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/* 3v8LzS3@  
**Utility.java FH~:&;  
*/ dJ"M#
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package NetFox; yajdRU  

3_  
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public class Utility { ))"gWO  
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public Utility() _?tpO61g>  
{ |6E_N5~  
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} b:dN )m  
2*:q$c  
//线程睡眠 FZHA19Kb  
public static void sleep(int nSecond) N,(!
 
{ w*qj0:i5as  
try{ ]S6Gz/4aV+  
Thread.sleep(nSecond); nKx)R^]k  
} -o ).<&#  
catch(Exception e) ^hIdmTf6  
{ ]5ZXgz  
e.printStackTrace (); Su#0F0  
} %* "+kwZ  
} Tc WCr  
-#v~;Ci  
//日志 I3t5S;_8  
public static void log(String sMsg) +?_!8N8  
{ @62T:Vl  
System.err.println(sMsg); 5ya9VZ5#  
} ')m!48  
/v{+V/'+  
t-\+t<;
 
public static void log(int sMsg) 4V+bE$Wu  
{ Itl8#LpLM  
System.err.println(sMsg); Uj!3MF  
} cn'>dz3v  
} F? #3  
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,B
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/* yaUtDC.|  
**TestMethod.java F y+NJSG  
*/ ? wS}'  
package NetFox; 8!
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)qWwh)\;!  
f|d~=\0y  
public class TestMethod { z*.AuEK?  
Kd\0nf6  
&.A_d+K&  
public TestMethod() O. * 0;5  
{ ///xx/weblogic60b2_win.exe z:QDWH  
try{ c{q+h V=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O NabL.CV  
SiteFileFetch fileFetch = new SiteFileFetch(bean); J)|3jbX"I]  
fileFetch.start(); EC+t-:a]  
} i<uU_g'M  
catch(Exception e){e.printStackTrace ();} 8Pn  
g"-j/ c  
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} (,Y[2_Zv  
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public static void main(String[] args) f:;-ZkIU ?  
{ DV5hTw0  
new TestMethod(); osp~)icun  
} Fis!MMh.$  
} iI GK"}  
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