http断点续传简单实现（java)

/* hCM+=]z"  
**SiteFileFetch.java tM
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*/ <.#i3!  
package NetFox; fi`*r\  
import java.io.*; C4ge_u#  
import java.net.*; ``U>9S"p)  
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public class SiteFileFetch extends Thread { GkVV%0;&J1  
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SiteInfoBean siteInfoBean = null; //文件信息Bean c.r]w  
long[] nStartPos; //开始位置 z" 4$mh  
long[] nEndPos; //结束位置 [WuN?H  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -:Y
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long nFileLength; //文件长度 y3kXfSe  
boolean bFirst = true; //是否第一次取文件 0rooL<~fa  
boolean bStop = false; //停止标志 _>0I9.[5  
File tmpFile; //文件下载的临时信息 KftZ^mk+p  
DataOutputStream output; //输出到文件的输出流 uK1DC i  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ZE#A?5lb  
public SiteFileFetch(SiteInfoBean bean) throws IOException /aNlr>^  
{ sZA7)Z
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siteInfoBean = bean; fn;`Vit#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l'm!e'7_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F{v>   
if(tmpFile.exists ()) J.35Ad1hM  
{ ?`lIsd  
bFirst = false; K8daSvc  
read_nPos(); qJj"WU5  
} 6;Wns'  
else b
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{ a/^ojn  
nStartPos = new long[bean.getNSplitter()]; 3P N<J  
nEndPos = new long[bean.getNSplitter()]; %xPJJ$P  
} 7\HjQ7__  
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} oP!oU2eqK  
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public void run() !W^P|:Qt  
{ ~x4]^XS  
//获得文件长度 5LMAy"  
//分割文件 f0S$p R  
//实例FileSplitterFetch jI[Y< (F ;  
//启动FileSplitterFetch线程 =*>ri  
//等待子线程返回 )
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try{ 5bBY[qp  
if(bFirst) epXvk
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{ 5L!EqB>m;  
nFileLength = getFileSize(); %=e^MN1  
if(nFileLength == -1) h&}z@  
{ {_C2c{  
System.err.println("File Length is not known!"); =jz [}5  
} 4sMA'fG  
else if(nFileLength == -2) [&eG>zF"  
{ POB6#x  
System.err.println("File is not access!"); Klrd|;C  
} YMXhzqj  
else @^R6}qJ  
{ B:oE&Ahh{  
for(int i=0;i<nStartPos.length;i++) r^zra|]  
{ t.X8c/,;g  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >=O5=\`  
} Op<,e{[]  
for(int i=0;i<nEndPos.length-1;i++) &65I 6  
{ e>J.r("f  
nEndPos = nStartPos[i+1]; @KJ~M3d0l  
} E/OfkL*\  
nEndPos[nEndPos.length-1] = nFileLength; U'*~Ju  
} 7G':h0i8  
} %/.yGAPkx  
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//启动子线程 @}\wec_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; iewwL7  
for(int i=0;i<nStartPos.length;i++) c'md)nD2M  
{ H'a6] ]2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d RIuA)0s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <~z@GMQCf  
nStartPos,nEndPos,i); 40=*Ul U-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dC>[[_  
fileSplitterFetch.start(); !:2_y'hA  
} #n_t5 O[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5J~@jPU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); o#uhPUZ
 
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #u"$\[G  
nEndPos = " + nFileLength); bUU\bc  
// fileSplitterFetch[nPos.length-1].start(); br;~}GR_h
 
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//等待子线程结束 3;?DKRIcX  
//int count = 0; GahIR9_2  
//是否结束while循环 >1BDt:G36  
boolean breakWhile = false; bt=z6*C>A  
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while(!bStop) ech1{v\B|  
{ U{52bH<  
write_nPos(); AB+HyZ*//  
Utility.sleep(500); \ lW*.<  
breakWhile = true; T-F8[dd^/  
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for(int i=0;i<nStartPos.length;i++) ^]k=*>{ R  
{ h^v+d*R N  
if(!fileSplitterFetch.bDownOver) E3V_qT8  
{ 'i:S=E F  
breakWhile = false; f]NaQ!. 7  
break; xey?.2K1A  
} * `3+x  
} Owz>g4l r  
if(breakWhile) |
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break; {Q021*xt/  
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//count++; }6To(*  
//if(count>4) ;>CM1  
// siteStop(); II]-mb  
} nmw#4yHYy:  
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System.err.println("文件下载结束！"); <YAs0  
} 3ih:t'N-  
catch(Exception e){e.printStackTrace ();} 8;i
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} Dc9Fb^]QOG  
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J9&#);(  
//获得文件长度 8Xa{.y"  
public long getFileSize() \7WZFh%:  
{ _b! TmS#F1  
int nFileLength = -1; LIRL`xU7  
try{ , }B
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URL url = new URL(siteInfoBean.getSSiteURL()); YeI|&FMX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .2 }5Dc,eR  
httpConnection.setRequestProperty("User-Agent","NetFox"); ? @- t.N  
]Wn=Oc{F  
2,rjy|R`  
int responseCode=httpConnection.getResponseCode(); xJ^pqb  
if(responseCode>=400) %'MR;hQsd8  
{ .*Axr\x3  
processErrorCode(responseCode); wKE}BO >  
return -2; //-2 represent access is error P\3H<?@4  
} NKYHJf2?x  
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String sHeader; JqK-vvI  

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for(int i=1;;i++) ]#\/1!W
  
{ 3J[ 5^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Uc0S
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//Utility.log(in.readLine()); ]GiDfYs7%  
sHeader=httpConnection.getHeaderFieldKey(i); \4|osZ0y  
if(sHeader!=null) e0g>.P@6  
{ 'ALe>\WO  
if(sHeader.equals("Content-Length")) ui&^ m,  
{ ogJ>`0 +J  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); A}CpyRVCn  
break; U=N]XwjVK<  
} sDS0cc6e  
} sf,9Ym  
else $+n5l@W  
break; i&Me7=~  
} =UV=F/Af^  
}
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catch(IOException e){e.printStackTrace ();} 98%6Z8AS6U  
catch(Exception e){e.printStackTrace ();} l)qGG$7$  
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Utility.log(nFileLength); tVHQ$jJY%  
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return nFileLength; 9|2LuHQu+  
} ~c'R7E&Bfa  
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//保存下载信息（文件指针位置） C-;}a%c"  
private void write_nPos() p/?TU  
{ 'p4b8:X  
try{ l?zWi[Zf  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6'JP%~QlS  
output.writeInt(nStartPos.length); lPn&,\9@~  
for(int i=0;i<nStartPos.length;i++) qR8 BS4q_p  
{ !gG\jC~n  
// output.writeLong(nPos); N0
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output.writeLong(fileSplitterFetch.nStartPos); jIL$hqo  
output.writeLong(fileSplitterFetch.nEndPos); ]]_H|tO  
} {-,^3PI\  
output.close(); -0:B2B  
} hionR)R4  
catch(IOException e){e.printStackTrace ();} %M;{+90p>t  
catch(Exception e){e.printStackTrace ();} E3E$_<^  
} uT{.\qHo  
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P8;f^3V(+/  
//读取保存的下载信息（文件指针位置） ot.R Gpg%  
private void read_nPos() :]-? l4(%  
{ AV?<D.<  
try{ 0%5x&vx'S  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jY5BVTWnV  
int nCount = input.readInt(); \ /6
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nStartPos = new long[nCount]; Ia>>b #h  
nEndPos = new long[nCount]; me/ae{  
for(int i=0;i<nStartPos.length;i++) P7p'j  
{ Nx"v|"  
nStartPos = input.readLong(); IP+1 :M  
nEndPos = input.readLong(); x_|:3I  
} 0 ;ov^]  
input.close(); LdYaJh~h  
} |h65[9DMP  
catch(IOException e){e.printStackTrace ();} -}r(75C  
catch(Exception e){e.printStackTrace ();} YK|Y^TU^  
} sYY=MD  
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private void processErrorCode(int nErrorCode) O"x/O#66  
{ |A@Gch fd  
System.err.println("Error Code : " + nErrorCode); =v]
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} "6%vVi6  
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//停止文件下载 L8j#lu  
public void siteStop() N^8 lfc$a  
{ r&-Ir3[  
bStop = true; hDs.4MZC`  
for(int i=0;i<nStartPos.length;i++) Rd.[8#7VE  
fileSplitterFetch.splitterStop(); G0eJ<*|_ 3  
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} q7%eLJ  
} 5CuK\<  
//负责部分文件的抓取 uH-*`*  
**FileSplitterFetch.java T4{&@b 0*  
*/ CfnRcnms  
package NetFox; +kTa>U<?  
}qOC*k:  
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import java.io.*; '((Ll  
import java.net.*; g1`/xJz|  
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public class FileSplitterFetch extends Thread { s(I7}oRWsL  
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String sURL; //File URL ;zO(bj>  
long nStartPos; //File Snippet Start Position >AW=N  
long nEndPos; //File Snippet End Position '2%/h4jY  
int nThreadID; //Thread's ID L%.GKANM  
boolean bDownOver = false; //Downing is over l@om2|B  
boolean bStop = false; //Stop identical &p$SFH?s  
FileAccessI fileAccessI = null; //File Access interface V ;)q?ZHg  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ; (+r)r_  
{ b\w88=|  
this.sURL = sURL; :/IcFU~)M  
this.nStartPos = nStart; (&$|R\W.  
this.nEndPos = nEnd; 1XO*yZF  
nThreadID = id; M
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 Yn}_"FO'  
} 9c=_p'G3Fw  
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public void run() FBcF  
{ yX(6C]D  
while(nStartPos < nEndPos && !bStop) %d9UWQ  
{ $0Y&r]'  
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try{ z~xN]=  
URL url = new URL(sURL); ?Ib/}JST  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); h tn2`  
httpConnection.setRequestProperty("User-Agent","NetFox"); t?]6>J_V  
String sProperty = "bytes="+nStartPos+"-"; %Ys>PzM  
httpConnection.setRequestProperty("RANGE",sProperty); #?i#q%q  
Utility.log(sProperty); y=\jQ6Fc  
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InputStream input = httpConnection.getInputStream(); mor
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//logResponseHead(httpConnection); |pp@  
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byte[] b = new byte[1024]; dTaR8i  
int nRead; j78xMGKO  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) GD'C^\EaZ  
{ .VmI4V?}h  
nStartPos += fileAccessI.write(b,0,nRead); ZjEO$ts=@  
//if(nThreadID == 1) 5 ^iU1\(L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); B<[;rk  
} E!VAA=  
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Utility.log("Thread " + nThreadID + " is over!"); KF'H|)!K  
bDownOver = true; *4qsM,t  
//nPos = fileAccessI.write (b,0,nRead); tTyu,%/m  
} .KT+,Y  
catch(Exception e){e.printStackTrace ();} c)SSi@< cv  
} :*&wnQMKR  
} im+2)9f  
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//打印回应的头信息 nHKEtKDd  
public void logResponseHead(HttpURLConnection con) `CK;,>i   
{ X{#@ :z$  
for(int i=1;;i++) ^^?DYC   
{ G-3.-  
String header=con.getHeaderFieldKey(i); #K!Df%,<  
if(header!=null) pLzsL>6h  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 45j+n.9=  
Utility.log(header+" : "+con.getHeaderField(header)); (4{49b  
else <\^X,,WtO  
break; :/%Vpdd@  
} ^MJGY,r6b  
} hCT%1R}rKr  
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public void splitterStop() ITc/aX  
{ aG}9Z8D  
bStop = true; Pz|qy,  
} }h_Op7.5D  
@?B=8VHR  
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} mZ;yk(  
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/* `FJnR~d  
**FileAccess.java GPR`=]n& &  
*//文件访问(定位，写) xk|$Oa  
package NetFox; ri JyH;)  
import java.io.*; eN> (I
W  
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public class FileAccessI implements Serializable{ |}M']Vz  
9x?;;qC"m9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o@>c[knJ  
RandomAccessFile oSavedFile; Etu>z+P!  
long nPos; xD\Km>|i  
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public FileAccessI() throws IOException h{* O9O<  
{ p fBO5Ys  
this("",0); _kY5
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} zi?'3T%Ie  
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public FileAccessI(String sName,long nPos) throws IOException MW`a>'0t?  
{
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oSavedFile = new RandomAccessFile(sName,"rw"); "}OFwes
  
this.nPos = nPos; q5vs;,_ |  
oSavedFile.seek(nPos); /2@%:b)  
} 0X0D8H(7Q  
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public synchronized int write(byte[] b,int nStart,int nLen) gw*d"~A  
{ m@O\Bi}=}  
int n = -1; 9wq%Fnt  
try{ ZM#WdP  
oSavedFile.write(b,nStart,nLen); @Qs-A^.  
n = nLen; 1=;QWb6  
} ]F@md(J  
catch(IOException e) :>X7(&j8  
{ I }/Oi]jA6  
e.printStackTrace (); li%-9Jd  
} &16bZw  
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return n; *[SsvlFt  
} H*\[:tPa  
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} R{
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/* NdNfai  
**SiteInfoBean.java %7d"()L  
*/ n21$57`4  
package NetFox; c}QJ-I  
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public class SiteInfoBean { UeICn@)\y  
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private String sSiteURL; //Site's URL JG<3,>@%  
private String sFilePath; //Saved File's Path pMB=iS<E  
private String sFileName; //Saved File's Name 7P`1)juA9  
private int nSplitter; //Count of Splited Downloading File (Z$6JNkz  
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s =5H.q%PV  
public SiteInfoBean() q],R6GcVr  
{//nSplitter的缺省值为5 bvgD;:Aj  
//default value of nSplitter is 5 O2,g]t~C  
this("","","",5); W<LaR,7  
} >ek%P;2w>  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Dy@\!F  
{ 9(l'xuX  
sSiteURL= sURL; =_dd4`G&<  
sFilePath = sPath; cP2R24th  
sFileName = sName; &JlR70gdHi  
this.nSplitter = nSpiltter; .zAafi0  
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} VjqdKQeVq  
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public String getSSiteURL() 9Bk}g50$#  
{ be/1-=m  
return sSiteURL; n`}&,UA$4  
} N 9&@,3  
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public void setSSiteURL(String value) GF!{SO4  
{ GnOo+hB  
sSiteURL = value; lDU:EJ&DHE  
} !5OMAWNU@  
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public String getSFilePath() ]2%P``Yj  
{ \r%Vgne-g  
return sFilePath; VQ?H:1R  
} x#0@$  
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public void setSFilePath(String value) V3W85_*  
{
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sFilePath = value; (YJAT  
} N`Xnoehu  
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4_%FSW8-  
public String getSFileName() CDYx/yO  
{ jN}7BbX  
return sFileName; ^X;Xti  
} ~fp+@j-A  
3t8H?B12ow  
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public void setSFileName(String value) /C"s_:m;3  
{ fF>qU-  
sFileName = value; YaZt+WA  
} $ XsQ e  
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"$IwQ  
public int getNSplitter() j'*p  
{ x\hn;i<  
return nSplitter; !J=;Z9  
} WQLL[{mhS  
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0*;9CH=BE  
public void setNSplitter(int nCount) :5K~/=6x  
{ f76|  
nSplitter = nCount; 6>BDA?  
} A%*DQ1N  
} R,w54},  
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/* Z^`=!n-V  
**Utility.java g} ~<!VpX  
*/ 3:8nwt  
package NetFox; 4EhBpTg  
:$cSQ(q9a  
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public class Utility { 
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public Utility() K# i*9sM  
{ )~blx+\y  
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} 8cBW] \ v  
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//线程睡眠 S[hJ{0V  
public static void sleep(int nSecond) E"1;i  
{ ?tC}M;~  
try{ g.Caapy  
Thread.sleep(nSecond); B mBzOk^  
} /yw\(|T  
catch(Exception e) 8@W/43K8-  
{ `^bvj]>l  
e.printStackTrace (); [OoH5dD  
} ;p#Z:6  
} -6~dJTm[t  
1|EU5<  
//日志 p-yOiG8b}  
public static void log(String sMsg) a,57`Ks+n<  
{ >,"D9!  
System.err.println(sMsg); &Rl3y\ r  
} [5p7@6:$u  
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^8-~@01.`_  
public static void log(int sMsg) k|$"TFXx;  
{ }u3H4S<o  
System.err.println(sMsg); L >Ez-  
} "'}v0*[  
} %I|+_ z&x  
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/* 1^60I#Vr@  
**TestMethod.java W]!@Zlal  
*/ l\sS?  
package NetFox; 2
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ycl>git]  
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public class TestMethod { o3i,B),K  
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public TestMethod() R%
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{ ///xx/weblogic60b2_win.exe RlslF9f  
try{ j""y2c1  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .,ppGc|*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^iV`g?z  
SiteFileFetch fileFetch = new SiteFileFetch(bean); d
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fileFetch.start(); 94h_t@Q/1  
} 0x]OF8=J  
catch(Exception e){e.printStackTrace ();} ~D-JZx  
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0[2BY]`Z.  
} (ifqwl62  
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public static void main(String[] args) @tE&<[e  
{ Rg8m4xw  
new TestMethod(); s}[A4`EWH  
} ;o_V!<$  
}
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