http断点续传简单实现（java)

/* \1k79c  
**SiteFileFetch.java 'g}
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*/ zYH&i6nj  
package NetFox; 8?xE6  
import java.io.*; )W^F2-{  
import java.net.*; ju8>:y8  
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public class SiteFileFetch extends Thread { hZ|z|!g0  
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Ki;*u_4{  
SiteInfoBean siteInfoBean = null; //文件信息Bean g_;\iqxL  
long[] nStartPos; //开始位置 "BM#4  
long[] nEndPos; //结束位置 fW?vdYF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 P0;n9>g  
long nFileLength; //文件长度 /p/]t,-j2  
boolean bFirst = true; //是否第一次取文件 |Tv#4st  
boolean bStop = false; //停止标志 pIc#L>{E  
File tmpFile; //文件下载的临时信息 KYB`D.O  
DataOutputStream output; //输出到文件的输出流 s n8Qk=K  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Na<pwC  
public SiteFileFetch(SiteInfoBean bean) throws IOException 4S7v:1~xe  
{ J"0`%'*/  
siteInfoBean = bean; Sh/08+@+L:  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .#EFLXs  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  0HZ{Y9]  
if(tmpFile.exists ()) 6,pnw  
{ FnwJ+GTu  
bFirst = false; i}cRi&2[  
read_nPos(); ncaT?~u j  
} atj(eg  
else u^&^UxCA  
{ y5vvu>nd  
nStartPos = new long[bean.getNSplitter()]; R|'ybW'Y  
nEndPos = new long[bean.getNSplitter()]; AzPu)  
} QFA8N  
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} 49eD1h3'X[  
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public void run() R7%#U`Q^A  
{ +V2F#fI/  
//获得文件长度 \UA[  
//分割文件 (|2t#'m  
//实例FileSplitterFetch C2!|OQ9A2  
//启动FileSplitterFetch线程 n3WlZ!$  
//等待子线程返回 aHD]k8m z  
try{ pd?Mf=>#  
if(bFirst) G0Iw-vf  
{ ldf\;Qk  
nFileLength = getFileSize(); [DuttFX^x  
if(nFileLength == -1) :'Vf g[Uq  
{ )705V|v  
System.err.println("File Length is not known!"); TP*hd  
} vz&|J   
else if(nFileLength == -2) 7P} W *  
{ 9i:L&dN  
System.err.println("File is not access!"); ;[ZEDF5H  
} Y_liA  
else xR~hwj  
{ e1yt9@k,  
for(int i=0;i<nStartPos.length;i++) ,KH#NY]  
{ J4hL_i
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); fuW\bo3  
} 3<Lx&p~%T  
for(int i=0;i<nEndPos.length-1;i++) 6XxvvMA97  
{ y RqL9t  
nEndPos = nStartPos[i+1]; 10Q ]67  
} !aUs>1i  
nEndPos[nEndPos.length-1] = nFileLength; PI {bmZ  
} }{Pp]*I<A  
} 4Z3su^XR  
1C+13LE$U  
/|}EL%a  
//启动子线程 iqsCB%;5  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; A`%k:@  
for(int i=0;i<nStartPos.length;i++) U gat1Pz  
{ g&L!1<, p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 70?\ugxA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [g|_~h  
nStartPos,nEndPos,i); : $1?i)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8S TvCH"Z_  
fileSplitterFetch.start(); "x0^#AVg  
} sI
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AYBns]!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #^0R&) T
 
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", VD*6g%p  
nEndPos = " + nFileLength); .^`{1%  
// fileSplitterFetch[nPos.length-1].start(); ~12EQacOT  
7sCG^&Y  
[(i  
//等待子线程结束 :U|1xgB  
//int count = 0; B`)BZ,#p  
//是否结束while循环 e+7"/icK  
boolean breakWhile = false; u[;\y|75  
NWESP U):w  
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while(!bStop) Oi.C(@^(  
{ tAd%#:K  
write_nPos(); ,L2ZinU:  
Utility.sleep(500); l\H=m3Bg  
breakWhile = true; BKCiIfkZ  
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for(int i=0;i<nStartPos.length;i++) <dWv?<o  
{ +HpA:]#Y  
if(!fileSplitterFetch.bDownOver)  tU5zF.%  
{ o'aEY<mZ7  
breakWhile = false; QE+g j8  
break; /KaZH
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} b
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} Pbn*
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if(breakWhile) x;.Jw6g  
break; VBlYvZ;$*  
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//count++; eb\K "ec"  
//if(count>4) }0*@fO  
// siteStop(); "S]0  
} 9<?M8_  
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System.err.println("文件下载结束！"); 9rX&uP)j^#  
} $99n&t$Y  
catch(Exception e){e.printStackTrace ();} @gEUm_#HTs  
} D/gw .XYL  
.hb:s,0mP  
5V~oIL  
//获得文件长度 ?4}h&/  
public long getFileSize() xIW3={b3  
{ i^&~?2  
int nFileLength = -1; Vm(y7}Aq{  
try{ 7aRi5  
URL url = new URL(siteInfoBean.getSSiteURL()); p`dU2gV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?p{Nwl#  
httpConnection.setRequestProperty("User-Agent","NetFox"); y14;%aQN  
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int responseCode=httpConnection.getResponseCode(); 2,oKVm+  
if(responseCode>=400) ?=7cF  
{ 2zA4vZkbcw  
processErrorCode(responseCode); :pY/-Cgv  
return -2; //-2 represent access is error *;slV3  
} +o{R _  
M/'sl;  
[
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String sHeader; O63<AY@  
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for(int i=1;;i++) -0 a/$h  
{ f}ji?p  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2]jn '4  
//Utility.log(in.readLine()); Sv#XIMw{,  
sHeader=httpConnection.getHeaderFieldKey(i); XEp{VC@=  
if(sHeader!=null) [!uG1GJ>  
{ 4he GnMD  
if(sHeader.equals("Content-Length")) Zn+.
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{ %XDc,AR[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); HZB>{O  
break; 'F3f+YD  
} aiUY>M#|  
} TER=*"!  
else (t K||*
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break; 7IH@oMvE  
} (N6i4 g6  
} kZ .gO  
catch(IOException e){e.printStackTrace ();} sf qL|8  
catch(Exception e){e.printStackTrace ();} \ a<h/4#|  
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Utility.log(nFileLength); "Yv_B3p   
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return nFileLength; #U4F0BdA  
} Gr'  CtO  
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//保存下载信息（文件指针位置） 4r#= *  
private void write_nPos() 85$m[+md  
{ 8I?Wt W  
try{ [A~xy'T  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ]NY~2jmX  
output.writeInt(nStartPos.length); -#[a7',Z;  
for(int i=0;i<nStartPos.length;i++) 6dt]`zv/  
{ z+wA rPxc  
// output.writeLong(nPos); G@\1E+Ip  
output.writeLong(fileSplitterFetch.nStartPos); }5[qo`M  
output.writeLong(fileSplitterFetch.nEndPos); / }X1W  
} '~<m~UXvD#  
output.close(); #aJ(m&  
} sN*N&XG  
catch(IOException e){e.printStackTrace ();} . B9iLI  
catch(Exception e){e.printStackTrace ();} LV
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} Ecefi pG  
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//读取保存的下载信息（文件指针位置）  .Wj;%|  
private void read_nPos() B$ PP&/  
{ py!|\00}  
try{ t;Sb/3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )h4f\0  
int nCount = input.readInt(); )gIKH{JYL  
nStartPos = new long[nCount]; 0
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nEndPos = new long[nCount]; Xm}/0g&7  
for(int i=0;i<nStartPos.length;i++) jDfC=a])  
{ _\G"9,)u'  
nStartPos = input.readLong(); 7M!I8C0!aO  
nEndPos = input.readLong(); HxV=F66"  
} I\{ 1u  
input.close(); Y@vTaE^w3  
} 9'giU r  
catch(IOException e){e.printStackTrace ();} n8 i] z  
catch(Exception e){e.printStackTrace ();} @7]yl&LZ  
} !8d{q)JZ  
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private void processErrorCode(int nErrorCode) SCHP L.n  
{ vn!3l1\+J  
System.err.println("Error Code : " + nErrorCode); 5h-SC
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} Tod&&T'UW  
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//停止文件下载 zuad~%D<I  
public void siteStop() 85:=4N%  
{ T|eu  
bStop = true; 9igiZmM  
for(int i=0;i<nStartPos.length;i++) Q800y??&J  
fileSplitterFetch.splitterStop(); dI(@
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} 2d #1=+V  
} KNvZm;Q6  
//负责部分文件的抓取 gnOt+W8  
**FileSplitterFetch.java y<|7z99L  
*/ O7m(o:t x3  
package NetFox; mbTEp*H  
 i{NzV  
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import java.io.*; -`kW&I0  
import java.net.*; W
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t ;;U}
 
public class FileSplitterFetch extends Thread { IqaT?+O\?r  
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v\gLWq'  
String sURL; //File URL \5:i;AE  
long nStartPos; //File Snippet Start Position zm5]J  
long nEndPos; //File Snippet End Position wx= $2N6  
int nThreadID; //Thread's ID ?}tFN_X"  
boolean bDownOver = false; //Downing is over *=/ { HvJ  
boolean bStop = false; //Stop identical p Z|V 3  
FileAccessI fileAccessI = null; //File Access interface x_N'TjS^{  
Iby\$~V  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #uG%j  
{ 6$Xzpg(o  
this.sURL = sURL; WYm\)@  
this.nStartPos = nStart; nLZTK&7}  
this.nEndPos = nEnd; pk$l+sNZ=  
nThreadID = id; A5I)^B<(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 rxvx  
} MDZ640-Y  
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_ @NL;w:!  
public void run() kzQ+j8.,U  
{ GX!G>  
while(nStartPos < nEndPos && !bStop) pHXm>gTd,J  
{ A@!qv#'  
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try{ oi&VgnSk  
URL url = new URL(sURL); HSE!x_$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +ZaSM~   
httpConnection.setRequestProperty("User-Agent","NetFox"); B dj!ia;H  
String sProperty = "bytes="+nStartPos+"-"; #C74z$  
httpConnection.setRequestProperty("RANGE",sProperty); T= y}y  
Utility.log(sProperty); ["k,QX  
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InputStream input = httpConnection.getInputStream(); )Pa'UGY  
//logResponseHead(httpConnection); ah4N|zJ>v  
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byte[] b = new byte[1024]; *Mh
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int nRead; z;,u}u}aI  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) m{Wu" ;e  
{ Y1W1=Uc uk  
nStartPos += fileAccessI.write(b,0,nRead); K,;E5  
//if(nThreadID == 1) ?
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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F4-$~v@  
} K*vt;L  
In"ZIKaC  
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Utility.log("Thread " + nThreadID + " is over!"); YNyk1cE  
bDownOver = true;  j|DsG,  
//nPos = fileAccessI.write (b,0,nRead); ` xEx^P^7  
} XSwl Tg  
catch(Exception e){e.printStackTrace ();} oQ/E}Zk@  
} ]KKS"0a  
}
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//打印回应的头信息 x*\Y)9Vgy  
public void logResponseHead(HttpURLConnection con) {=9,n\85#  
{ zOAd~E  
for(int i=1;;i++) %8B}Cb&2c  
{ A7Cm5>Y_S  
String header=con.getHeaderFieldKey(i); kYP#SH/  
if(header!=null) CAig]=2'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :S{BbQ){]  
Utility.log(header+" : "+con.getHeaderField(header)); \j}ZB<.>  
else K^)Eb(4  
break; '5#^i:  
} 1APe=tJ  
} aB2FC$z  
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public void splitterStop() w_"E*9  
{ ONB{_X?  
bStop = true; @p9i  
} )Yh+c=6 ?  
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} ^,lIK+#Elz  
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/* htO+z7  
**FileAccess.java Y!aSs3c  
*//文件访问(定位，写) kUL'1!j7  
package NetFox; u"r`3P`  
import java.io.*; ?8H8O %Z8  
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P[G)sA_"  
public class FileAccessI implements Serializable{ kf\PioD8  
q<x/Hat)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 R^8o^z['6u  
RandomAccessFile oSavedFile; TM_
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long nPos; n$A9_cHF7  
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public FileAccessI() throws IOException 58}U^IW  
{ 6IN e@  
this("",0); hIYNhZv  
} y1jCg%'H  
)
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public FileAccessI(String sName,long nPos) throws IOException K(e$esLs-  
{ 1SQ3-WUs  
oSavedFile = new RandomAccessFile(sName,"rw"); Ljm[?*H#  
this.nPos = nPos; V@.Ior}w  
oSavedFile.seek(nPos); IkL#SgY  
} o)M}!MT  
>jDDQ@  
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public synchronized int write(byte[] b,int nStart,int nLen) <`8n^m*  
{ { T/[cu<  
int n = -1; T= 80,  
try{ kUb>^- -K  
oSavedFile.write(b,nStart,nLen); 3,_aAgeE  
n = nLen; o"s)eh  
} W
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catch(IOException e) u74[>^  
{ `z}?"BW|  
e.printStackTrace (); hE:9{;Gf  
} (fH#I tf  

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return n; >>4qJ%bL  
} +)AG*  
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} %:f&.@'r  
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/* ~p6 V,Q  
**SiteInfoBean.java EgEa1l!NSQ  
*/ dM.f]-g  
package NetFox; (' (K9@}  
GhAlx/K  
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public class SiteInfoBean { B&M%I:i  
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private String sSiteURL; //Site's URL Ot0ap$&  
private String sFilePath; //Saved File's Path TIqtF&@o4  
private String sFileName; //Saved File's Name /$Ir5=B  
private int nSplitter; //Count of Splited Downloading File I.(,hFx;  
{S]}.7`l9(  
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public SiteInfoBean() o+iiSTJEe  
{//nSplitter的缺省值为5 7DogM".}~Q  
//default value of nSplitter is 5 5+4IN5o]=  
this("","","",5); %@J.{@>  
} LG9+GszX 2  
VcE:G#]5  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) UkwP  
{ d UE,U=  
sSiteURL= sURL; .<0ye_S'y  
sFilePath = sPath; 98c(<  
sFileName = sName; =`oCLsz=  
this.nSplitter = nSpiltter; )bL'[h
 
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} D(op)]8  
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public String getSSiteURL() /|m2WxK)  
{ S&5&];Ag  
return sSiteURL; H\"sgoJ  
} [o#oak{U  
qCC.^8  
JAnZdfRt  
public void setSSiteURL(String value) wD}l$& +  
{ .&iawz  
sSiteURL = value; IVnHf_PzF  
} ?/E~/;+7=  
|fJ};RLI"  
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public String getSFilePath() ' ,wFTV&  
{ Xh"n]TK  
return sFilePath; .[KrlfI  
} F@jZ
ho  
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V*;(kEqj  
public void setSFilePath(String value) GT.,  
{ np^N8$i:n  
sFilePath = value; dm0R[[7  
} yx8z4*]kH  
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`:fZ)$sY  
public String getSFileName()  :A_@,Q  
{ ,Ks8*;#r  
return sFileName; WM$ MPs  
} l~q\3UKlt  
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public void setSFileName(String value) ,.8KN<A2]'  
{ vzAaxk%  
sFileName = value; qH>d  
} oUlY?x1  
@CL{D:d  
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public int getNSplitter() SYJD?&C;  
{ ?pmHFlx  
return nSplitter; VQt0 4?  
} 3,3N^nSD  
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public void setNSplitter(int nCount) ^98~U\ar  
{ !sP{gi#=  
nSplitter = nCount; wH&!W~M  
} f|c{5$N!  
} k@J&IJ  
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/* s?}e^/"v  
**Utility.java :J@gmY:C  
*/ +.[ <%  
package NetFox; `5.'_3  
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public class Utility { |v%YQ R  
%)W2H^  
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public Utility() U(g:zae  
{ L|xbR#v  
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{rw|#Z>A  
} &%DY\*  
;bib/  
//线程睡眠 8qTys8  
public static void sleep(int nSecond) dn
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{ s};{ZAtE  
try{ ?Ep [M:,q  
Thread.sleep(nSecond); K=k"a  
} n
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catch(Exception e) }2.`N%[  
{ WX?IYQ+  
e.printStackTrace (); k$R-#f;  
} KwSqKI7]0  
} HCs?iJ  
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//日志 a~}OZ&PG  
public static void log(String sMsg) 1};Stai'  
{ 9}<ile7^  
System.err.println(sMsg); <0&*9ZeD  
}  "Og7rl  
24*XL,  
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public static void log(int sMsg) IueFx u  
{ )23H1  
System.err.println(sMsg); IY\5@PVZ  
} "7F?@D$e  
} BLiF 5  
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/* _op}1   
**TestMethod.java <)c)%'v  
*/ Fj3a.'  
package NetFox; 0gr/<v  
h2]P]@nW;W  
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public class TestMethod { !ons]^km  
qiBVGH  
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public TestMethod() @,7GaK\  
{ ///xx/weblogic60b2_win.exe k)=s>&hl  
try{ jcf7n`L  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YfKdR"i+.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8^+%I/S$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 04P}-L,  
fileFetch.start(); ,j_i?Ff  
} !``,gExH  
catch(Exception e){e.printStackTrace ();} u^I|T.w<r6  
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29
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} e2oa($9  
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public static void main(String[] args) zL0pw'4
 
{ {ROVvs`  
new TestMethod(); Vv=. -&'  
} |3"KK  
} +lcbi  
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