http断点续传简单实现（java)

/* MZ0 J/@(  
**SiteFileFetch.java #jQITS7  
*/ lyP<&<Y5  
package NetFox; ~MOIrF  
import java.io.*; -0Ps.B  
import java.net.*; '2eggX%  
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public class SiteFileFetch extends Thread { Fb
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SiteInfoBean siteInfoBean = null; //文件信息Bean \j4TDCs_[  
long[] nStartPos; //开始位置 e7-U0rrE  
long[] nEndPos; //结束位置 OF}vY0oiw?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 z&w@67 >j  
long nFileLength; //文件长度 %k9GoX
_  
boolean bFirst = true; //是否第一次取文件 y:mXv<g  
boolean bStop = false; //停止标志 V V<Zl  
File tmpFile; //文件下载的临时信息 Z\n nVM=  
DataOutputStream output; //输出到文件的输出流 bO9X;}\6  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Wh,p$|vL  
public SiteFileFetch(SiteInfoBean bean) throws IOException `rvS(
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{ {q:6;yzxl  
siteInfoBean = bean; uZCPxog  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); L+&$/1h]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?e0ljx;  
if(tmpFile.exists ()) F&^u1RYz  
{ alyWp  
bFirst = false; o
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read_nPos(); +ps(9O/B>  
} 1j
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else /@:I\&{f'9  
{ [&51m^  
nStartPos = new long[bean.getNSplitter()]; `j9 ;9^  
nEndPos = new long[bean.getNSplitter()]; A2..gs/  
} Yf1?3(0O  
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} G@s rQum(  
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public void run() `KB;3L  
{ 6YNd;,it>p  
//获得文件长度 L\aG.\  
//分割文件 voiWf?X  
//实例FileSplitterFetch 5y0N }}  
//启动FileSplitterFetch线程 wZ0RI{)s'  
//等待子线程返回 UZz/v#y~  
try{ `fS$@{YI_  
if(bFirst) zt6GJz1q  
{ Kqm2TMO]>V  
nFileLength = getFileSize(); m9 1Gc?c  
if(nFileLength == -1) @kd`9Yw  
{ G8}k9?26(  
System.err.println("File Length is not known!"); jBb:)
  
} 1N,</<"  
else if(nFileLength == -2) qx|~H'UuBN  
{ G0)}?5L1J  
System.err.println("File is not access!"); 4}`z^P<C  
} EV/DJ$C }  
else )\Am:?RH;  
{ DZ"'GQSg  
for(int i=0;i<nStartPos.length;i++) 7v't# =  
{ fS?}(7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \,D>zF  
} evjj~xkt
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for(int i=0;i<nEndPos.length-1;i++) sFt"2TVr3  
{ l|v`B6(  
nEndPos = nStartPos[i+1]; Ir#]p9:x  
} [>![ViX  
nEndPos[nEndPos.length-1] = nFileLength; pLSh +*F  
} FJCs$0  
} 7H.3.j(L  
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//启动子线程 _0}u0fk  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Ogv9_X8  
for(int i=0;i<nStartPos.length;i++) >e>%AMzo[  
{ {>g{+Eq  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ia@ |+r  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $O3.ex V  
nStartPos,nEndPos,i); gWQ(
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q<0X80w>  
fileSplitterFetch.start(); > 9.%hSy  
} C cPOK2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9:R3+,ZN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); b+1!qNuCW#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 1%ENgb:8  
nEndPos = " + nFileLength);
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// fileSplitterFetch[nPos.length-1].start(); H-\Ym}BGu  

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//等待子线程结束 9HB+4q[  
//int count = 0; xpX<iT>5u  
//是否结束while循环 u8.F_'`z  
boolean breakWhile = false; _AzI\8m  
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while(!bStop) t0,=U8]w  
{ tq}MzKI*  
write_nPos(); ClG\Kpirh  
Utility.sleep(500); E5!vw@,  
breakWhile = true; A3)"+`&PUl  
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for(int i=0;i<nStartPos.length;i++) d~ +(g!  
{ EHN(K-  
if(!fileSplitterFetch.bDownOver) OClG d
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{ oqAO@<dL!  
breakWhile = false; 0<7sM#sI!  
break; auga`*  
} _3(rwD
 
} !wN2BCSY@  
if(breakWhile) \3OEC`  
break; Ge_fU'F  
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//count++; "AU.Eh"-1  
//if(count>4) nNq<x^@83  
// siteStop(); l`.z^+!8@  
} KLvAe
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System.err.println("文件下载结束！"); "
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} ^D<CoxG  
catch(Exception e){e.printStackTrace ();} L&c & <+0T  
} :.4O Hp1  
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//获得文件长度 6@TU9AZS`  
public long getFileSize() A|GtF3:G  
{ 8tQ;N'  
int nFileLength = -1; XwUa|"X6  
try{ ?r KbL^2  
URL url = new URL(siteInfoBean.getSSiteURL()); 10fxK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d7Vp^^}(  
httpConnection.setRequestProperty("User-Agent","NetFox"); R\|,GZ!`+  
1~t.2eUG  
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int responseCode=httpConnection.getResponseCode(); yUj`vu2  
if(responseCode>=400) o3V\  
{ <Y."()}GeH  
processErrorCode(responseCode); o2X95NiH  
return -2; //-2 represent access is error :`e#I/,  
} ?h6|N%U'  
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String sHeader; S=ZZ[E_~S  
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for(int i=1;;i++) 4^uSW&`;/  
{ E{EO9EI  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )
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//Utility.log(in.readLine()); +!0K]$VZs  
sHeader=httpConnection.getHeaderFieldKey(i); @QV0l]H0+  
if(sHeader!=null) *#'j0;2F  
{ tBbOxMm0  
if(sHeader.equals("Content-Length")) a;t}'GQGk  
{ ss[`*89  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); wn.~Dx  
break;  ][wb4$2  
} ]R_R`X?  
} n9xP8<w8  
else Iz1x|EQ  
break; [a04
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} `p
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} tGgxID  
catch(IOException e){e.printStackTrace ();} <Cv(@A->  
catch(Exception e){e.printStackTrace ();} [K&%l]P7  
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Utility.log(nFileLength); O;~e^ <*  
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return nFileLength; lFGuQLuqA{  
} &1$d`>fn  
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//保存下载信息（文件指针位置） ^K;k4oK  
private void write_nPos() EY)2,  
{ ZU73UL  
try{ g%&E~V/g$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >E>yA d  
output.writeInt(nStartPos.length); mY.v:  
for(int i=0;i<nStartPos.length;i++) 1Z)Et,  
{ 8cG?p  
// output.writeLong(nPos); @j^R+F  
output.writeLong(fileSplitterFetch.nStartPos); Z1eT>6|]r  
output.writeLong(fileSplitterFetch.nEndPos); rZKfb}ANQ  
} wAKHD*M)  
output.close(); m<h%BDSzr{  
} /?eVWCR  
catch(IOException e){e.printStackTrace ();} iM@$uD$_Q2  
catch(Exception e){e.printStackTrace ();} q#tUDxf(|  
} 5p (zhfuG  
'
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//读取保存的下载信息（文件指针位置） eR$@Q  
private void read_nPos() LH5Z@*0#  
{ }T@=I&g;  
try{ ~Q&J\'GQH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); HU'Mi8xxy  
int nCount = input.readInt(); M76p=*  
nStartPos = new long[nCount]; 5EFt0?G  
nEndPos = new long[nCount]; inWLIXC,  
for(int i=0;i<nStartPos.length;i++) ,X.[37  
{ z:>cQUYl  
nStartPos = input.readLong(); 2aj1IBnz6/  
nEndPos = input.readLong(); 8:$h&aBI  
}
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input.close(); =]%JTGdp(  
} vN Bg&m  
catch(IOException e){e.printStackTrace ();} |NuMDVd+s  
catch(Exception e){e.printStackTrace ();} CRK%^3g  
} <rBW6o7  
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private void processErrorCode(int nErrorCode) g&s. 0+  
{ PMfW;%I.  
System.err.println("Error Code : " + nErrorCode); 4yyw:"  
} ib=)N)l  
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//停止文件下载 (`1io  
public void siteStop() G-d7}Uz?  
{ hzo> :U  
bStop = true; "'U^8NA2  
for(int i=0;i<nStartPos.length;i++) 4>d4g\Z0L  
fileSplitterFetch.splitterStop(); >Zb!?ntN`t  
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} '^UHY[mX8  
} Zw]"p63eMa  
//负责部分文件的抓取 <tD,Uu{P  
**FileSplitterFetch.java fz(YP=@ZnP  
*/ #EH=tJgO|J  
package NetFox; BU:;;iV8  
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import java.io.*; 9{u=  
import java.net.*; #AJW-+1g.=  
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public class FileSplitterFetch extends Thread { ;z'&$#pA  
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String sURL; //File URL TTXF r  
long nStartPos; //File Snippet Start Position $ VT)  
long nEndPos; //File Snippet End Position
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int nThreadID; //Thread's ID L/i'6(="  
boolean bDownOver = false; //Downing is over z@,pT"rb  
boolean bStop = false; //Stop identical 1}d F,e  
FileAccessI fileAccessI = null; //File Access interface
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g88k@<Y  
{ jZA1fV  
this.sURL = sURL; p*Z<DEh#  
this.nStartPos = nStart; ,X|Oe@/  
this.nEndPos = nEnd; if*V-$[I  
nThreadID = id; G"/;Cq=t  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2P"643tz  
} LKM018H>  
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public void run() >V"{]v  
{ E=I'$*C\D  
while(nStartPos < nEndPos && !bStop) ]3 "0#Y  
{ w){B$X
  
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try{ rS [4Pey  
URL url = new URL(sURL); Y/sav;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'gY?=,dF>  
httpConnection.setRequestProperty("User-Agent","NetFox"); SY,ns*>1F  
String sProperty = "bytes="+nStartPos+"-"; RdX+:!lD  
httpConnection.setRequestProperty("RANGE",sProperty); tK3$,9+  
Utility.log(sProperty); MSCH6R"5  
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InputStream input = httpConnection.getInputStream(); Q`k;E}x_-  
//logResponseHead(httpConnection); &{Z+p(3Gj  
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byte[] b = new byte[1024]; 7J);{ &x9h  
int nRead; bW
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -HF?1c  
{ k6#$Nb606  
nStartPos += fileAccessI.write(b,0,nRead); v?He]e'  
//if(nThreadID == 1) jkk%zu  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _ s 3aaOL  
} O~5t[  
1K/HVj+'.  

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Utility.log("Thread " + nThreadID + " is over!"); #w;"s*  
bDownOver = true; n*[ZS[I  
//nPos = fileAccessI.write (b,0,nRead); 3eUi
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} 02,t  
catch(Exception e){e.printStackTrace ();} ~>@~U]  
} -8)Hulo/{U  
} &b (*  
/`M#  
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//打印回应的头信息 ]WMzWt:L  
public void logResponseHead(HttpURLConnection con) "mn?*  
{ ,1I-%6L  
for(int i=1;;i++) {iyJHY  
{ LVUA"'6V  
String header=con.getHeaderFieldKey(i); `+Nv=vk  
if(header!=null) vd%AV(]<LJ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "nz\YQdg  
Utility.log(header+" : "+con.getHeaderField(header)); 8=D,`wog  
else F > rr.  
break; ~7b#BXzP  
} oaj.5hM  
} X+Sqw5rH  
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public void splitterStop() |Ua);B~F  
{ _)j\ b  
bStop = true; JL {H3r&/S  
} :i{M1z I  
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} 4V9BmVS|Th  
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/* g{Av =66Z  
**FileAccess.java ASdW!4.p  
*//文件访问(定位，写) =R:O`qdC4e  
package NetFox; %f CkR`:  
import java.io.*; !n;3jAl&$  
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public class FileAccessI implements Serializable{ d%I7OBBx@
 
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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 qUfoEpW2=6  
RandomAccessFile oSavedFile; GLIY!BU<C  
long nPos; )&E]  
 3*Q=)}  
-"zW"v)\  
public FileAccessI() throws IOException ;'Hu75ymo  
{ r\QV%09R  
this("",0); aEzf*a|fSV  
} or#] ![7N  
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@|cH
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public FileAccessI(String sName,long nPos) throws IOException E-1u_7  
{ Z;N3mD+\ye  
oSavedFile = new RandomAccessFile(sName,"rw"); *04}84?:  
this.nPos = nPos; ekY)?$v3  
oSavedFile.seek(nPos); 6*B%3\z)  
} GPni%P#a@0  
5`3x(=b  
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public synchronized int write(byte[] b,int nStart,int nLen) }8AH/  
{ kxJs4BY
0  
int n = -1; 0e&&k  
try{ 5=*i!c _m  
oSavedFile.write(b,nStart,nLen); <#8}![3Q  
n = nLen; <}RD]Sc$1  
} HY_>sD  
catch(IOException e) CF3x\6.q}  
{ \A^8KVE!  
e.printStackTrace (); (Zx--2lc  
} q~#>MB}".  
q{V e%8$"  
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return n; e<uf)K=(
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} 0,-]O=   
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} ;HAvor=?  
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/* hlreeXv  
**SiteInfoBean.java )n"0:"Ou  
*/ 2u-J+  
package NetFox; u`wD6&y*  
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public class SiteInfoBean { )-"<19eu  
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MA_YMxP.'  
private String sSiteURL; //Site's URL M._E$y,5  
private String sFilePath; //Saved File's Path [(a3ljbRX  
private String sFileName; //Saved File's Name ..h@QQ  
private int nSplitter; //Count of Splited Downloading File q.R(>Zc
V  
4pMp@b  
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public SiteInfoBean() 6|'7Mr~\  
{//nSplitter的缺省值为5 ;o)'dK  
//default value of nSplitter is 5 s]e`q4ip  
this("","","",5); 8pf]M&  
} Jw=7eay$F  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) R|}4H*N  
{ SVZ@'X\[M  
sSiteURL= sURL; :~Ra}  
sFilePath = sPath; Y,L[0%  
sFileName = sName; X]9<1[f  
this.nSplitter = nSpiltter; lH?jqp
  
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} 2.</n}g  
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public String getSSiteURL() g||EjCsp  
{ !"<rlB,J  
return sSiteURL; \:@7)(p\;  
} LN(\B:wAY  
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public void setSSiteURL(String value) 3n)Kzexh  
{ 8mmnnf{P  
sSiteURL = value; Z" H;t\P  
} *tT}N@<%  
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public String getSFilePath() SIm1fC  
{ qZE3T:S  
return sFilePath; A@_>9;   
} ~9APc{"A  
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;=IJHk1&  
public void setSFilePath(String value) <sm"3qs"_  
{ vO$cF*  
sFilePath = value; ` ;mQ"lO  
} ceJ#>Rj  
:sK4mRF  
l]D$QT3  
public String getSFileName() 'bLP#TAzf  
{ j&/+/s9N  
return sFileName; {hOS0).(w7  
} (Nz`w  
"CC"J(&a  
8pA<1H%  
public void setSFileName(String value) [*It' J^  
{ 55ec23m  
sFileName = value; N;YF
r  
} fsK=]~<g  
6Q>:vQ+E  
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public int getNSplitter() tA4Ra,-c  
{ Oq% TW|a#  
return nSplitter; :4 z\Q]  
} 3QZm *. /"  
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public void setNSplitter(int nCount) d])ctxB  
{ /N%i6t<xU  
nSplitter = nCount; li?@BHEf  
} +\%]<YO  
} ox<&T|  
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/kyO,g$9  
/* H;_Ce'oU(  
**Utility.java Jb$G  
*/ 12L`
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package NetFox; qHgtd+ I  
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public class Utility { i)(G0/:  
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public Utility() &0[L2x}7  
{ uUx7>algF  
>G"fMOOkW  
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} h]~FYY  
aqqo>O3 s  
//线程睡眠 %X\A|V&  
public static void sleep(int nSecond) Hicd -'  
{ F-o?tU  
try{ k kD#Bb  
Thread.sleep(nSecond); f^QC4hf0  
} x.t&NP^V)  
catch(Exception e) P}a$#a'!  
{ am3JzH  
e.printStackTrace (); #E=8kbD7  
} i" u|119  
} =AzkE]  
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//日志 GK,{$SC+=  
public static void log(String sMsg) t
 3N}):  
{ t@#5 G* _Q  
System.err.println(sMsg); (i(E~^O  
} EI?8/c  
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public static void log(int sMsg) ` W);+s  
{ OMmfTlM%  
System.err.println(sMsg); ; \co{_&D  
} ?-Of\fNu  
} 6rmx{Bt  
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r6Vw!^]8u8  
/* $ eL-fg  
**TestMethod.java 1TA!9cz0Z  
*/ G8w@C
 
package NetFox; q Sv!5&u  
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public class TestMethod { h"8[1 ;  
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public TestMethod() fX,O9d$  
{ ///xx/weblogic60b2_win.exe WW3Jxd  
try{ 8/)q$zs  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %YF /=l  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {_.(,Z{  
SiteFileFetch fileFetch = new SiteFileFetch(bean); mMZrBz7r  
fileFetch.start(); X#0yOSR  
} 5M'cOJ  
catch(Exception e){e.printStackTrace ();} [bo"!Qk%  
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} =Oh$pZRymu  
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public static void main(String[] args) ljrJC  
{ 6=JJ!`"<2  
new TestMethod(); Cpd>xXZz&S  
} u:(=gj,~
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} +ru`Zw5,  
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