http断点续传简单实现（java)

/* l|+$4 Nb2  
**SiteFileFetch.java XR]bd  
*/ ;):;H?WS|A  
package NetFox; `Ku:%~$/  
import java.io.*; NtGJpT4YX  
import java.net.*; #i~P])%gNP  
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public class SiteFileFetch extends Thread { .+(ED  
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SiteInfoBean siteInfoBean = null; //文件信息Bean b B#QIXY/L  
long[] nStartPos; //开始位置 ~5Fx[q  
long[] nEndPos; //结束位置 wYe;xk`>  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }alq~jY  
long nFileLength; //文件长度 N?c~AEk9U  
boolean bFirst = true; //是否第一次取文件 }bihlyB&Q  
boolean bStop = false; //停止标志 xw{K,;WeO  
File tmpFile; //文件下载的临时信息 4Kt0}W  
DataOutputStream output; //输出到文件的输出流 @=G[mc\  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )z&C&Gqz  
public SiteFileFetch(SiteInfoBean bean) throws IOException $@s-OQ}  
{ 0]f/5jvLj  
siteInfoBean = bean; 8'E7Uj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); sI6*.nR  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Y*b$^C%2  
if(tmpFile.exists ()) X
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{ N5W!(h)  
bFirst = false; .
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read_nPos(); ?6"U('y>n  
} R{[v#sF >#  
else "KF]s.  
{ !pj&h0CR  
nStartPos = new long[bean.getNSplitter()]; p+ReQ.5|  
nEndPos = new long[bean.getNSplitter()]; HJb^l 4Q  
} Tcv/EST  
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} 9e.v[K~  
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public void run() 3ut<o-
 
{ ^fN/  
//获得文件长度 ?*UWg[  
//分割文件
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//实例FileSplitterFetch kbvF 9#  
//启动FileSplitterFetch线程 -+i7T^@|  
//等待子线程返回 -p0*R<t  
try{ c0l?+:0M  
if(bFirst) 16N|  
{ S -,$ (  
nFileLength = getFileSize(); f/z]kfgw  
if(nFileLength == -1) >mtwXmI  
{ Zqf ovG
 
System.err.println("File Length is not known!"); F<iV;+  
} w_"-rGV  
else if(nFileLength == -2) uzb|yV'B  
{ Ve9)?=!  
System.err.println("File is not access!"); %
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} mYfHBW:  
else -1hCi!  
{ _J2?B?S/j  
for(int i=0;i<nStartPos.length;i++) Jj0:p"  
{ 3QXs
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); @:Ft+*2  
} }s"].Xm^2  
for(int i=0;i<nEndPos.length-1;i++) C \5yo  
{ *Cp:
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nEndPos = nStartPos[i+1]; ffI=Bt]t  
} d%L/[.&  
nEndPos[nEndPos.length-1] = nFileLength; 74NL)|M  
} ./zzuKO8XK  
} vo:h"ti  
*6][[)(  
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//启动子线程 6)ysiAH?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Jw;G_dQ[  
for(int i=0;i<nStartPos.length;i++) "Q\b6 7Ch  
{ wmX(%5vY^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,jW a&7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I\-M`^@  
nStartPos,nEndPos,i); (i\{hq/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OrL4G `O  
fileSplitterFetch.start(); Z6-  
} YIIc@)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v=dK2FaY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); gw">xt5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", M17+F?27M  
nEndPos = " + nFileLength); /V2yLHm  
// fileSplitterFetch[nPos.length-1].start(); s^.tj41Gx}  
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//等待子线程结束 Xwu&K8q21  
//int count = 0; j%ZBAk)}  
//是否结束while循环 eNH9`Aa  
boolean breakWhile = false; I!(BwYd  
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while(!bStop) uK#2vgT  
{ u] G  
write_nPos(); `SZ-o{  
Utility.sleep(500); r? }|W2^%  
breakWhile = true; eA``fpr  
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for(int i=0;i<nStartPos.length;i++) * RX^ z6  
{ 8df| 9E$  
if(!fileSplitterFetch.bDownOver) ] M#LB&Pe  
{ kaoiSL<[6  
breakWhile = false; )lz)h*%#  
break; *c%{b3T_  
} m;1/+qs0  
} 9s7TLT k  
if(breakWhile) 6Z=Qs=q  
break; e_l|32#/  
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//count++; E{^W-  
//if(count>4) sk:B;.z  
// siteStop(); v>mK~0.$  
} zTPNQ0=|  
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System.err.println("文件下载结束！"); JrX. f  
} ZzQLbCV  
catch(Exception e){e.printStackTrace ();} Nq6; z)$  
} !&.-{ _$  
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//获得文件长度 Q Wc^}#!!  
public long getFileSize() QUZ+#*:s  
{ \hEIQjfi  
int nFileLength = -1; z yp3+|  
try{ Wi,)a{  
URL url = new URL(siteInfoBean.getSSiteURL()); G^.tAO5:f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Xx2t0AIB  
httpConnection.setRequestProperty("User-Agent","NetFox"); }J-e:FUF#  
1_
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int responseCode=httpConnection.getResponseCode(); ~4twI*f  
if(responseCode>=400) C9""sVs  
{ 'n\PS,[1R  
processErrorCode(responseCode); .LnknjC  
return -2; //-2 represent access is error mb%U~Na  
} %.'oY%  
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String sHeader; ,!PV0(F(  
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for(int i=1;;i++) s%>8y\MaK  
{ bR:hu}YS  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); O 9M?Wk :  
//Utility.log(in.readLine()); t. (6tL]  
sHeader=httpConnection.getHeaderFieldKey(i); =8rNOi  
if(sHeader!=null) yOAC<<Tzus  
{ Mc(|+S@w'  
if(sHeader.equals("Content-Length")) nZ#u#V  
{ 3Z` wU  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); voTP,R[}85  
break; [f[Wz{Q#Y  
} !"-.D4*r  
} iTT%_-X-  
else Fq oh!F  
break; Gxxz4   
} |YV> #l  
} e"{"g[b/7  
catch(IOException e){e.printStackTrace ();} ,q7FK z{  
catch(Exception e){e.printStackTrace ();} >p;&AaXkoG  
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Utility.log(nFileLength); JY;u<xl  
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return nFileLength; -XK;B--c  
} (plT/0=^t  
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//保存下载信息（文件指针位置） gf9U<J#&C  
private void write_nPos() ty4R2LnC  
{ ro3%VA=V  
try{ #N~1Ye  
output = new DataOutputStream(new FileOutputStream(tmpFile)); nG{o$v_|  
output.writeInt(nStartPos.length); 5~im.XfiVx  
for(int i=0;i<nStartPos.length;i++) Q00v(6V46  
{ :("@U,  
// output.writeLong(nPos); oe3=QE  
output.writeLong(fileSplitterFetch.nStartPos); 8|L@-F  
output.writeLong(fileSplitterFetch.nEndPos); Zg>]!^X8  
} ,w9|?%S  
output.close(); 2dHsM'ze  
} x'OP0],#  
catch(IOException e){e.printStackTrace ();} 3p?nQ O)L  
catch(Exception e){e.printStackTrace ();} C+%eT&
OO  
} fOdqr  
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//读取保存的下载信息（文件指针位置） ^K_FGE0ec  
private void read_nPos() /(u? k%Q  
{ VZ">vIRyi|  
try{ ]l+<-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); n\<7`,  
int nCount = input.readInt(); ,S<) )  
nStartPos = new long[nCount]; =VT\$ 5A  
nEndPos = new long[nCount]; Qnt9x,
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for(int i=0;i<nStartPos.length;i++) 6U$e;cr6  
{ \Y8 sIs  
nStartPos = input.readLong(); 7sWe32  
nEndPos = input.readLong(); |-S+x]9  
} "O|.e`C%^  
input.close(); }; M@JMu,  
} :=5X)10
 
catch(IOException e){e.printStackTrace ();} $/@  L  
catch(Exception e){e.printStackTrace ();} !y>up+cRjl  
} `g)  
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private void processErrorCode(int nErrorCode) 6%:~.ZfN  
{ 'Nuy/\[{\  
System.err.println("Error Code : " + nErrorCode); P{:Zxli0  
} 2mMi=pv9  
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//停止文件下载 [u^ fy<jdp  
public void siteStop() {.[EXMX  
{ J|^z>gP(  
bStop = true; mh`uvqY  
for(int i=0;i<nStartPos.length;i++) A=Hv}lv  
fileSplitterFetch.splitterStop(); zxH<~2
 
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} 6BEpnw>p(  
} R$A%Zh6  
//负责部分文件的抓取 c#1kg@q@  
**FileSplitterFetch.java ^8]7  
*/ )C{20_  
package NetFox; V[]Pya|s+  
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import java.io.*; oSf`F1;)HQ  
import java.net.*; |:4?K*w",  
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public class FileSplitterFetch extends Thread { $<C",&  
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String sURL; //File URL Li0+%ijM  
long nStartPos; //File Snippet Start Position l{ql'm  
long nEndPos; //File Snippet End Position  98^7pa  
int nThreadID; //Thread's ID j6$@vA)  
boolean bDownOver = false; //Downing is over _3wK: T{:  
boolean bStop = false; //Stop identical i+< v7?:`#  
FileAccessI fileAccessI = null; //File Access interface T<b*=i  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Kng=v~)N'  
{ o"z;k3(i$7  
this.sURL = sURL; S')
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this.nStartPos = nStart; hA1B C3  
this.nEndPos = nEnd; Z]bG"K3l  
nThreadID = id; {<gX~./]c  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 e{Vn{.i,5  
} IMMsOl  
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public void run() L;L_$hu)  
{ }R5EuR m\  
while(nStartPos < nEndPos && !bStop) 2EN}"Du]mj  
{ Ui9;rh$1eU  
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try{ ycki0&n3  
URL url = new URL(sURL); ,`!lZ| U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P$N5j~*  
httpConnection.setRequestProperty("User-Agent","NetFox"); @qjN>PH~  
String sProperty = "bytes="+nStartPos+"-"; bi+g=cS  
httpConnection.setRequestProperty("RANGE",sProperty); *B{
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Utility.log(sProperty); 0T#z"l<L  
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InputStream input = httpConnection.getInputStream(); f8qDmk5s  
//logResponseHead(httpConnection); bwP@}(K  
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byte[] b = new byte[1024]; s'l|Ii  
int nRead; z7L+wNYwg  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !wfUD2K1  
{ &+ PVY>q  
nStartPos += fileAccessI.write(b,0,nRead); %H&WihQ  
//if(nThreadID == 1) Y8IC4:EO  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J|be'V#]1  
} ?$tD  
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Utility.log("Thread " + nThreadID + " is over!"); 3XQe? 2:<  
bDownOver = true; 5 $$Cav  
//nPos = fileAccessI.write (b,0,nRead); "AKr;|m  
} \v<S:cTf  
catch(Exception e){e.printStackTrace ();} AcH!KbYf  
} G/fBeK$.  
} uV@'898%5  
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//打印回应的头信息 G,^ ?qbHg  
public void logResponseHead(HttpURLConnection con) m^m=/'<+  
{ *icaKy3  
for(int i=1;;i++) n+Conp/  
{ 9mv0}I  
String header=con.getHeaderFieldKey(i); x5pu+-h  
if(header!=null) F$1{w"&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); a_{'I6a*,  
Utility.log(header+" : "+con.getHeaderField(header)); C!+PBk[9  
else :"Tk
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break; 8
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} uR.pQo07y<  
} V lO^0r^z  
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public void splitterStop() 3B,dL|q(@J  
{ ~]?EV?T  
bStop = true; KydAFxUb  
} \T<F#a  
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} DKem;_6OQ  
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/* "*l{ m2"  
**FileAccess.java v3t<rv  
*//文件访问(定位，写) (e!Yu#-  
package NetFox; SAf)#HXa  
import java.io.*; /n>vPJvz  
*14:^neoI  
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public class FileAccessI implements Serializable{ Y$c7uA:4  
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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 _Ye.29  
RandomAccessFile oSavedFile; c'Ibgfx%
m  
long nPos; H]wP\m)  
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public FileAccessI() throws IOException ?Ov~\[) F  
{ T@#?{eA  
this("",0); 8*{jxN'M  
} :)B1|1  
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public FileAccessI(String sName,long nPos) throws IOException i1KjQ1\a+  
{ S# baOO  
oSavedFile = new RandomAccessFile(sName,"rw"); i`];xNR'  
this.nPos = nPos; O<,\tZ'N  
oSavedFile.seek(nPos); @]2aPs} }6  
} 'o0o.&/=  
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public synchronized int write(byte[] b,int nStart,int nLen) 2|B@s3a  
{ 8<C@I/  
int n = -1; $9X?LGUz  
try{ vJVh%l+  
oSavedFile.write(b,nStart,nLen); }''0N1,/  
n = nLen; 3c wBPqH  
} #;@I.  
catch(IOException e) ~EXCYUp4v  
{ R~[~(`/S  
e.printStackTrace (); 2Kr>93O  
} }opMf6`w  
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return n; d^!3&y&  
} RIO?rt;  
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} F!/-2u5gF  
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$ #GuV'  
/* yuJ>xsM  
**SiteInfoBean.java /0fsn_  
*/ ;E.f%  
package NetFox; n$7*L9)(C  
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public class SiteInfoBean { \awkt!Wa  
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private String sSiteURL; //Site's URL 8tna<Hx  
private String sFilePath; //Saved File's Path Gx}`_[-  
private String sFileName; //Saved File's Name r#&JfAo  
private int nSplitter; //Count of Splited Downloading File
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X%(NI(+x,  
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public SiteInfoBean() GJ2ZK=/  
{//nSplitter的缺省值为5 /'_<~A  
//default value of nSplitter is 5 (pP.*`JRv  
this("","","",5); _JTK$\  
} j)YX=r;xM  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) WwtVuc|  
{ m}oR*<.  
sSiteURL= sURL; f/IQ2yT-:D  
sFilePath = sPath; f5un7,m  
sFileName = sName; }YM\IPsPu  
this.nSplitter = nSpiltter; e<a*@ P,  
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} _~C1M&b(X3  
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public String getSSiteURL() G{>PYLxOb  
{ e"bzZ!c&~V  
return sSiteURL; 7gB?rJHV,  
} ^ACrWk~UY  
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public void setSSiteURL(String value) 9rT^rTV  
{ f
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sSiteURL = value; 9y5JV3  
} KfZb=v;-l  
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public String getSFilePath() zb"4_L@m2  
{ )rAJ>;  
return sFilePath; '@M"#`#0  
} q+p}U}L= k  
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public void setSFilePath(String value) 8Lx1XbwK  
{ "$o>_+U  
sFilePath = value; BKb#\(95*  
} K{`R
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public String getSFileName() xfI0P0+  
{ i4h`jFS  
return sFileName; ,c?( |tF  
} $ xHtI]T  
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public void setSFileName(String value) OgC,oj,!/  
{ (Eo
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sFileName = value; 8-k`"QI=  
} 2fu<s^9dh  
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public int getNSplitter() h!|Uj  
{ r<:d+5"  
return nSplitter; uPr!;'J=  
} G `!A#As  
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public void setNSplitter(int nCount) GI,TE  
{ } S]!W\a  
nSplitter = nCount; jn(!6\n"  
} $cJ fdE  
} ~"J1@<  
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vxC];nCC#  
/* 4Otq3s34FT  
**Utility.java GQhy4ji'z  
*/ j3`Ya
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package NetFox; hi/d%lNZ  
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_ A#lyp  
public class Utility { FJCORa@?_  
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public Utility() 8IxIW0  
{ & /T}  
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} w{xa@Q]t-  
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//线程睡眠 jIrfJ*z  
public static void sleep(int nSecond) $':5uU1}  
{ T|D^kL%m!  
try{ ty"L&$bf  
Thread.sleep(nSecond); k+P3z&e  
} Bt,'g*Cs  
catch(Exception e) s5mJ -  
{ 3F!)7  
e.printStackTrace (); *c/V('D/  
} ,tg]Gt  
} $MwBt  
N wNxO  
//日志 hE`d@  
public static void log(String sMsg) !z4I-a  
{ sZr \mQ~  
System.err.println(sMsg); }[UH1+`L  
} Jj=N+,km  
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h4 9q(085V  
public static void log(int sMsg) eWex/ m  
{ fiA8W  
System.err.println(sMsg); XxdD)I  
} 6Y,&q|K  
} MaY_*[  
0uW)&>W  
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/* +}?%w|8||s  
**TestMethod.java Al8Dw)uG{  
*/ X@tA+  
package NetFox; I(7iD. ^:  
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s[h;9 I1w  
public class TestMethod { uM\\(g}  
H!X*29nX  
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public TestMethod() HpIi-Es7C  
{ ///xx/weblogic60b2_win.exe ILH[q>  
try{ 5EI"5&`*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Yu_ eCq5/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (2L,m  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  +@f  
fileFetch.start(); _xi&%F/  
} j#P4&  
catch(Exception e){e.printStackTrace ();} DBcR1c&<H  

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} hrzxc4,W  
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public static void main(String[] args) ,P`GIGvkA  
{ ^
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new TestMethod(); SIR2 Kc0  
} GeB&S!F  
}  ?f'`b<o  
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