http断点续传简单实现（java)

/* _a
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**SiteFileFetch.java L08lkq,  
*/ w/9%C(w6  
package NetFox; WM ]eb, 8q  
import java.io.*; 8KsP
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import java.net.*; !bCaDTz  
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public class SiteFileFetch extends Thread { Xwd9
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SiteInfoBean siteInfoBean = null; //文件信息Bean HKVtO%&  
long[] nStartPos; //开始位置 O-3aU!L  
long[] nEndPos; //结束位置 @]Ac >&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 drbim8!q~  
long nFileLength; //文件长度 eAjsMED  
boolean bFirst = true; //是否第一次取文件 |3`8$-  
boolean bStop = false; //停止标志 cNye@}$lu  
File tmpFile; //文件下载的临时信息 1-|aeJ  
DataOutputStream output; //输出到文件的输出流 gSe3S-Lt  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） MHA_b^7?  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7j
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{ thE9fr/  
siteInfoBean = bean; K87
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 1jpft3*x  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); RNt9Qdr4y  
if(tmpFile.exists ()) ?.Ip(g  
{ %l!-rXp  
bFirst = false; BKYyc6iE  
read_nPos(); F 1l8jB\  
} ClNuO  
else D2RvFlAXu  
{ \m=k~Cf:f  
nStartPos = new long[bean.getNSplitter()]; ,Kt51vGi  
nEndPos = new long[bean.getNSplitter()]; Y8N+v+V/  
} PZI6{KOis  
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} TIK'A<  
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public void run() 3PlIn0+LX  
{ yI^7sf7k  
//获得文件长度 *;U<b  
//分割文件 Lyit`j~yH  
//实例FileSplitterFetch V
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//启动FileSplitterFetch线程 Z*=$n_ G  
//等待子线程返回 X8wtdd]64  
try{ |
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if(bFirst) 7xfS%'=y"  
{ %"WhD'*z}  
nFileLength = getFileSize(); \s!x;nw[  
if(nFileLength == -1) D0>Pc9
 
{ 9Q'[>P=1  
System.err.println("File Length is not known!"); n
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} R`B} T<*
  
else if(nFileLength == -2) +,TrJg  
{ RE1M4UV.  
System.err.println("File is not access!"); )JJF}m=  
} ls~9qkAyLx  
else  ;v/un  
{ !OMCsUZ  
for(int i=0;i<nStartPos.length;i++) >]uu?!PU  
{ whm|"}x)u  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Xg;;< /Z  
} n~0MhE0H  
for(int i=0;i<nEndPos.length-1;i++) =ADOf_n}  
{ &(e5*Q  
nEndPos = nStartPos[i+1]; 7 D{%  
} G,<l}(tEG  
nEndPos[nEndPos.length-1] = nFileLength; Z*-a=u%gl'  
} T6."j_  
} ) $0>L5d:  
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Ty#sY'%  
//启动子线程 }0iHf'~DH*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Sh?eb  
for(int i=0;i<nStartPos.length;i++) k|{ 4"4r  
{ /_YTOSZjm  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1U?5/Ja  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >8b%*f8R  
nStartPos,nEndPos,i); ) TRUx  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O%haaL\  
fileSplitterFetch.start(); ~O]{m,)n  
} mkrVeBp  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7p1B"%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &I%E8E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", p}5413z5Z=  
nEndPos = " + nFileLength); SpYmgL?wJ  
// fileSplitterFetch[nPos.length-1].start(); FZIC|uz  
i%, 't  
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//等待子线程结束 b*/Mco 9O  
//int count = 0; #=;
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//是否结束while循环 /Gn0|]KI  
boolean breakWhile = false; DIJmISk  
)dh`aQ%N "  
RD=V`l{Z  
while(!bStop) L&~'SC  
{ upX@8WxR  
write_nPos(); H6Bw3I[  
Utility.sleep(500); lJdYR'/Wd  
breakWhile = true; 29m$S7[  
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7B\Q5fLQ  
for(int i=0;i<nStartPos.length;i++) $15H_X*!  
{ cOZBl;}  
if(!fileSplitterFetch.bDownOver) +S`cUn7  
{ ZKq#PB/.  
breakWhile = false; UEhFId  
break; ect$g#  
} `S.I,<&  
} mx UyD[|  
if(breakWhile) s`0IyQXVU  
break; W/}_y8q  
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 sFnR;  
//count++; #9F>21UU  
//if(count>4) Nh}u]<B  
// siteStop(); V!>j:"  
} |lZp5MOc  
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System.err.println("文件下载结束！"); 1iNMgA  
} =p"ma83  
catch(Exception e){e.printStackTrace ();} d>F.C>  
}  ST0TWE'  
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//获得文件长度 t`R{N1  
public long getFileSize() ^!0z+M:>^  
{
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int nFileLength = -1; 9qgs*]J
 
try{ `@v;QLD"d<  
URL url = new URL(siteInfoBean.getSSiteURL()); Nu\<Xr8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f-ceDn  
httpConnection.setRequestProperty("User-Agent","NetFox"); xSNGf@1b  
9%"`9j~H>  
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int responseCode=httpConnection.getResponseCode(); 72.Msnn  
if(responseCode>=400) p
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{ ~8"oH5  
processErrorCode(responseCode); #NYHw
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return -2; //-2 represent access is error ';c 6  
} oveK;\7/m  
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String sHeader; ICr.Gwe3_  
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aM(#J7;  
for(int i=1;;i++) P=6d<no&<  
{ wf &Jd:)4t  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h/5S2EB0!O  
//Utility.log(in.readLine()); +6 =lN[b  
sHeader=httpConnection.getHeaderFieldKey(i); mfS}+_ C  
if(sHeader!=null) KfYU.Q  
{ q-ko)]  
if(sHeader.equals("Content-Length")) he:z9EG}  
{ Xo]2iQy  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <lWj-+m  
break; }.Z`   
} /BD'{tZ]Sl  
} gIusp917  
else 0@{0#W3R  
break; *Uj;a.  
} k0#s{<I]E  
} VZ=:`)  
catch(IOException e){e.printStackTrace ();} \E<Qi3W>*  
catch(Exception e){e.printStackTrace ();} i/H;4
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Utility.log(nFileLength); tHHJ|4C  
@"1Z;.S8V  
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return nFileLength; ('UTjV  
} 0t}v@-abU  
dJQK|/  
eEP{?F^I[  
//保存下载信息（文件指针位置） l|E4 7@#  
private void write_nPos() >]ZE<.  
{ P}UxA!  
try{ H9_iTGBQ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2f@Cy+W'[  
output.writeInt(nStartPos.length); m'"H1~BW  
for(int i=0;i<nStartPos.length;i++) l>`66~+s,`  
{ }^$1<GT  
// output.writeLong(nPos); Ry"4v_e9  
output.writeLong(fileSplitterFetch.nStartPos); jC>#`gD  
output.writeLong(fileSplitterFetch.nEndPos); D GcpYA.7'  
} e&U$;sS`  
output.close(); R@s7s%y=  
} ipg`8*My  
catch(IOException e){e.printStackTrace ();} wytMoG\  
catch(Exception e){e.printStackTrace ();}
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} *PV"&cx  
7aKI=;60.  
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//读取保存的下载信息（文件指针位置） ~<9e}J  
private void read_nPos() J -Lynvqm  
{ -N wic|  
try{ OuEcoIK  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]@<VLP?  
int nCount = input.readInt(); (=;'>*L(  
nStartPos = new long[nCount]; +xO3<u  
nEndPos = new long[nCount]; eOF*|9  
for(int i=0;i<nStartPos.length;i++) =b>TFB=*N  
{ qHdUnW  
nStartPos = input.readLong(); PpBptsb^|J  
nEndPos = input.readLong(); EPH" 5$8  
} <!XunXh  
input.close(); +6P[TqR  
} ab%I&B<b  
catch(IOException e){e.printStackTrace ();} D&2NO/ R  
catch(Exception e){e.printStackTrace ();} o{fYoBgr  
} U5H%wA['m  
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private void processErrorCode(int nErrorCode) 1zH?.-  
{ g3&nxZ  
System.err.println("Error Code : " + nErrorCode); CJ%'VijhD  
} K8MET&  
,f>9oOqqA  
^>Z_3{s:$  
//停止文件下载 8h@L_*Kr  
public void siteStop() ]k
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{ Qkx*T9W  
bStop = true; yq k8)\p  
for(int i=0;i<nStartPos.length;i++) kk6 !krZ  
fileSplitterFetch.splitterStop(); T$%QK?B  
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} rf4f'cUa  
} gj @9(dk%  
//负责部分文件的抓取 cnQ2/ZZp~  
**FileSplitterFetch.java WPNw")t!  
*/ SJa>!]U'xI  
package NetFox; Z'y&11  
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import java.io.*; {.AN4  
import java.net.*; YW&K,)L@  
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public class FileSplitterFetch extends Thread { JZ`h+fAt  
g=Xy{Vm  
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String sURL; //File URL W}TP(~x'N  
long nStartPos; //File Snippet Start Position (?R!y -  
long nEndPos; //File Snippet End Position M(K7xx+G  
int nThreadID; //Thread's ID .\ fpjQW  
boolean bDownOver = false; //Downing is over ?{aJ#w  
boolean bStop = false; //Stop identical *nJ,|T  
FileAccessI fileAccessI = null; //File Access interface ou~$XZ7oi  
>4Tk#+%Jj  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tJ K58m$  
{ .x,y[/[[)  
this.sURL = sURL; OzrIiahz/  
this.nStartPos = nStart; u%z'.#r;a  
this.nEndPos = nEnd; (XmmbAbVom  
nThreadID = id; b/ \EN)  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;#9?3Os  
} fv+ET:
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public void run() XK3O,XM  
{ B!x#|vGXL  
while(nStartPos < nEndPos && !bStop) ZwLr>?0$ p  
{ ?rQ.nN  
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try{ Z+y'w#MZL  
URL url = new URL(sURL); a dr\l5pWQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iD|~$<9o  
httpConnection.setRequestProperty("User-Agent","NetFox"); '%ilF1#  
String sProperty = "bytes="+nStartPos+"-"; bS~Y
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httpConnection.setRequestProperty("RANGE",sProperty); T[1iZ  
Utility.log(sProperty); (:OMt2{r  
*1kFy_Gx  
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InputStream input = httpConnection.getInputStream(); Qw2-Vv4!"  
//logResponseHead(httpConnection); jGz~}&B  
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byte[] b = new byte[1024]; $RY-yKmi  
int nRead; u_' -vZ_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) t*H2
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{ ;6pB7N  
nStartPos += fileAccessI.write(b,0,nRead); m=@xZw<  
//if(nThreadID == 1) "Ux(n
t  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i@?|vu  
} 6}I X{nQI  
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Utility.log("Thread " + nThreadID + " is over!"); sGhw23  
bDownOver = true; &-Ch>:[  
//nPos = fileAccessI.write (b,0,nRead); J(d+EjC  
} 9MZ)-  
catch(Exception e){e.printStackTrace ();} hDB(y4/  
} 3WQa^'u  
} uGC5XX^  
.uauSx/#4  
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//打印回应的头信息 V;MmPNP|  
public void logResponseHead(HttpURLConnection con) ;a1DIUm'  
{ qCcLd7`$  
for(int i=1;;i++) B<r0y  
{ |X:`o;Uma  
String header=con.getHeaderFieldKey(i); uXFI7vV6P  
if(header!=null) /mz.HCs  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); K |=o-  
Utility.log(header+" : "+con.getHeaderField(header)); z*jaA;#  
else |}:}14ty  
break; )u{]rb[  
} |=YK2};  
} vi^YtA  
_";w*lg}  
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public void splitterStop() o5&b'WUJ=  
{ : pUu_  
bStop = true; <lIm==U<-  
} _xh)]R  
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} e`={_R{N  
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, p}:?uR  
/* < r~hU*u  
**FileAccess.java CUH u=  
*//文件访问(定位，写) `K+%/|!  
package NetFox; KZ[TW,Gw  
import java.io.*; |s/N?/qi  
Nkj$6(N=zJ  
~HGSA(  
public class FileAccessI implements Serializable{ SF;\*]["f  
zW#5 /*@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 P-2DBNB7  
RandomAccessFile oSavedFile; EoPvF`T  
long nPos; ^$'z#ZN1  
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9;6)b0=$  
public FileAccessI() throws IOException 0M;El2 P$  
{ QnS^ G{  
this("",0); ._tEDY/1m  
} 5`fUR/|[  
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public FileAccessI(String sName,long nPos) throws IOException QAxy?m,'  
{ 9HFEp-"  
oSavedFile = new RandomAccessFile(sName,"rw"); e< @$(w  
this.nPos = nPos; KPz0;2}  
oSavedFile.seek(nPos); BZ.l[LMp  
} ${z#{c1  
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sjLMM_'  
public synchronized int write(byte[] b,int nStart,int nLen) OW};i|  
{ meV Z_f/  
int n = -1; !Ltx2CB2]  
try{ ',`Qx{tQ)  
oSavedFile.write(b,nStart,nLen); aE)1LP  
n = nLen; `)8~/G%  
} _GxC|d  
catch(IOException e) w=_^n]`R  
{ {'+{ASpO!  
e.printStackTrace (); `+< ^Svou  
} >2>/ q?  
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return n; =\2gnk~  
} am?
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 YMv}]  
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} w?u3e+  
Mn&_R{{=  
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/* 3S_H&>K  
**SiteInfoBean.java ;\A_-a_(#  
*/ +|g*<0T5<  
package NetFox; rQT%~oM:  
LYYz=oZOE!  
0U%tjYk(  
public class SiteInfoBean { &8i$`6wY  
Y5CkCF  
\8ZVI98  
private String sSiteURL; //Site's URL A/a=)su  
private String sFilePath; //Saved File's Path CB>W# P%  
private String sFileName; //Saved File's Name (|AZO!  
private int nSplitter; //Count of Splited Downloading File X(E`cH |  
)b]!IP3  
ENqZ=Lyq  
public SiteInfoBean() %pxJ27Q  
{//nSplitter的缺省值为5 rlh:|#GTJ  
//default value of nSplitter is 5 y-H9fWi8Y&  
this("","","",5); EZiLXQd_  
} `,~'T [  
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j<!dpt  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) aTm R~k  
{ ML|?H1m>  
sSiteURL= sURL; tQNc+>7k+u  
sFilePath = sPath; $2*_7_Qb  
sFileName = sName; O95gdxc  
this.nSplitter = nSpiltter; aKW-(5<JW  
:D3:`P>,c  
k*2khh-  
} /8]
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public String getSSiteURL() 6FUcg40Y  
{ p8j4Tc5tQ>  
return sSiteURL; I__b$  
} NL|c5y<r  
7P2(q  
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public void setSSiteURL(String value) 3 []ltN_  
{ WPr:d  
sSiteURL = value; yR{rje*  
} ul_E{v  
*"_W1}^  
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public String getSFilePath() $FT6c@&y  
{ _\IA[-C+O  
return sFilePath; sd+_NtH  
} =pmG.>Si  
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g*FHZM*N9  
public void setSFilePath(String value) E|-5=!]fX  
{ nnBS;5  
sFilePath = value; hFycSu  
} #"r_ 3  
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public String getSFileName() w#a`k9
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{ jdVj FCl^#  
return sFileName; 1Z_w2D*  
} Qh
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public void setSFileName(String value) _-{=Z=?6}  
{ 1+3-Z>^e  
sFileName = value; 3TjyKB *!  
} DU,B  
;m|N9'  
kc$W"J@  
public int getNSplitter() E*T6kp^b  
{ 89 m.,  
return nSplitter; ^FNju/b  
} yRQ1Szbjli  
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 =v?V  
public void setNSplitter(int nCount) LdiNXyyzet  
{ O+'k4  
nSplitter = nCount; @JdeOL;  
} 3:$@DZT$  
} mV"F<G; H  
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U. <c#S  
/* Hxac#(,7  
**Utility.java sng6U;Z  
*/ &09~ D8f'  
package NetFox; O:,Gmft+  
?G9DSk?6%Z  
*b{Hj'HaH  
public class Utility { /'VuMMJ2  
8(NS;?  
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public Utility() beYGP  
{ wS$ 'gKA6  
{EoZ}I  
V$
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} 79 _8Oh  
AYoTCi%7E  
//线程睡眠 "\~>[on  
public static void sleep(int nSecond) M`=\ijUwN  
{ oWDn_GnG`h  
try{ `T%nGVl>\  
Thread.sleep(nSecond); =
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} GM^H )8U  
catch(Exception e) !3c+}j-j  
{ .;bU["fn)  
e.printStackTrace (); ,Bx0  
} =b)!l9TX  
} 8&+u+@H  
:*l\j"fX5  
//日志 tmoclK-  
public static void log(String sMsg) ?a,`{1m0\  
{ ?)Gb=   
System.err.println(sMsg); %qrUP\rn  
} E\Iz:ES^  
1"<{_&d1  
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public static void log(int sMsg) S n~P1C  
{ 9zBt a  
System.err.println(sMsg); g[ @Q iy  
} D7thLqA  
} $_a/!)bP  
8ce'G" b  
\
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/* "K|':3n|  
**TestMethod.java )g-0b@z!n  
*/ voP#}fD  
package NetFox; Kp;<z<  
NDe FY  
nhm#_3!6A  
public class TestMethod { fpzEh}:H\  
>)>~S_u  
,&O&h2=  
public TestMethod() 51AA,"2[_  
{ ///xx/weblogic60b2_win.exe KeyHxU=?  
try{ w17{2']  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); "yU<X\ni  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); tB}W )Eb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Ms%C:KG  
fileFetch.start(); CX{M@x3m  
} t08[3Q&  
catch(Exception e){e.printStackTrace ();} aiw4J  
@@!]Raj=  
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} =(,kjw88w  
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{FC<vx{42  
public static void main(String[] args) _39VL  
{ F Zt;D  
new TestMethod(); 7=wQ#bq"1P  
} -s91/|n  
} Ym-mfWo^#  
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