http断点续传简单实现（java)

/* H|(*$!~e  
**SiteFileFetch.java gZ79u  
*/ sKE*AGFLd  
package NetFox; hj
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import java.io.*; H)?" 8 s  
import java.net.*; ]0/~6f  
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public class SiteFileFetch extends Thread { 1W6n[
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SiteInfoBean siteInfoBean = null; //文件信息Bean v J,xz*rc`  
long[] nStartPos; //开始位置 J&] XLr.j  
long[] nEndPos; //结束位置 $[^ KCNB  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =t>`<T|(  
long nFileLength; //文件长度 ZRVF{D??"%  
boolean bFirst = true; //是否第一次取文件 -*]9Ma<wa  
boolean bStop = false; //停止标志 [{.\UkV@  
File tmpFile; //文件下载的临时信息 +kdU%Sm  
DataOutputStream output; //输出到文件的输出流 Ff1M~MhG  
*{4{<O<4  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） sN[@mAoH  
public SiteFileFetch(SiteInfoBean bean) throws IOException ggYIq*4  
{ `P)64So-1  
siteInfoBean = bean; < 8W:ij.`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); F4aJr%!\6S  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Zj /H3,7  
if(tmpFile.exists ()) 8
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{ P[|BWNei  
bFirst = false; 9iN!hy[  
read_nPos(); A.'`FtV  
} hTNYjXj  
else 7UEy L }N  
{ ,R9f;BR  
nStartPos = new long[bean.getNSplitter()]; @_tA"E  
nEndPos = new long[bean.getNSplitter()]; D4x'  
} |SJ% _#=i  
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} (x*2BEn|  
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public void run() f*R_\  
{ G%x,t-  
//获得文件长度 ,~68~_)  
//分割文件  !AD,  
//实例FileSplitterFetch a1Y_0  
//启动FileSplitterFetch线程 @+Anv~B.  
//等待子线程返回 y O9pEO|W  
try{ .q& ]wu  
if(bFirst) ,r)d#8  
{ I^C
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nFileLength = getFileSize(); [4(A458H  
if(nFileLength == -1) _ER cmP  
{ 0aq-drl5\  
System.err.println("File Length is not known!"); t)kr/Z*p\  
} )~o`QM+  
else if(nFileLength == -2) E(K$|k_>  
{ '5+, lRu  
System.err.println("File is not access!"); "r `6c0Z  
} GmWQJYX\  
else 'kONb  
{ OKNs (H  
for(int i=0;i<nStartPos.length;i++) oz5lt4  
{ \=:g$_l  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;U:o'9^9T  
} zYl+BM-j,6  
for(int i=0;i<nEndPos.length-1;i++) ]8j5Ou6#y  
{ 1oVDOo  
nEndPos = nStartPos[i+1]; uC$4TnoQx.  
} 1PjX:]:  
nEndPos[nEndPos.length-1] = nFileLength; XS~w_J#q  
} ok=E/77`  
} 5<'Jd3N{&  
u*YuU%H=  
7Bb@9M?i  
//启动子线程 7}HA_@[  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,2L,>?r6  
for(int i=0;i<nStartPos.length;i++) 
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{
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^L2Zo'y [  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ="Pyw
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nStartPos,nEndPos,i); Lm2cW$s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3n"&$q6  
fileSplitterFetch.start(); j1C0LP8  
} !7Q

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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9"v
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); JL*]9$o  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", O9 r44ww  
nEndPos = " + nFileLength); ?Pf ,5=*B  
// fileSplitterFetch[nPos.length-1].start(); |HIA[.q  
<@2?2l+`X  
/?<9,7#i  
//等待子线程结束 Sf8Xj|u  
//int count = 0; iO#xIl<  
//是否结束while循环 ,kuFTWB  
boolean breakWhile = false; ="*C&wB^  
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while(!bStop) =$`")3y3  
{ (#>5j7i8#  
write_nPos(); .6]cu{K(  
Utility.sleep(500); R~u7
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breakWhile = true; D}=i tu  
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}T(q"Vf~  
for(int i=0;i<nStartPos.length;i++) T%b^|="@  
{ ]7ZC>.t  
if(!fileSplitterFetch.bDownOver) 6v#sq  
{ ':fbf7EL<  
breakWhile = false; qdnNap
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break; nFOG=>c}  
} ~wV98u-N  
} vTa23YDW  
if(breakWhile) ]-]@=qYu  
break; 206jeH9  
1>*<K/\qg  
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//count++; j7%%/%$o[  
//if(count>4) W8/6  
// siteStop(); Y{B_OoTun  
} ;5S7_p2]j  
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= ft$j  
System.err.println("文件下载结束！"); w4/)r-Z4I  
} R3=E?us!  
catch(Exception e){e.printStackTrace ();} Pg}G4L?H;J  
} )bJ6{&  
0md{e`'q:  
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//获得文件长度 .jU0Hu{F4  
public long getFileSize() sm <kb@g  
{ F}mwQ%M  
int nFileLength = -1; t$Ji{t-  
try{ biuo.OG]  
URL url = new URL(siteInfoBean.getSSiteURL()); RB@gSHOc?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); MA QY/s~F  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^Rh~+  
{:+^[rerj  
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int responseCode=httpConnection.getResponseCode(); ))zaL2UP.  
if(responseCode>=400) nmAXU!t'  
{ ^OsUWhkV  
processErrorCode(responseCode); M0\[hps~X  
return -2; //-2 represent access is error S5p\J!k\B  
} =hb87g.  
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String sHeader; y9mZQq  
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for(int i=1;;i++) u
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{ tG&B D\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); a,\u|T:g  
//Utility.log(in.readLine()); ;Q 6e&Ips/  
sHeader=httpConnection.getHeaderFieldKey(i); 3 +9|7=d  
if(sHeader!=null) ;0{*V5A  
{ KPrxw }P  
if(sHeader.equals("Content-Length")) G->@  
{ $fG/gYvI\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @AyW9!vV;3  
break; ZPog)d@!  
} tV%\Jk),  
} e;\c=J,eE  
else Wx`IEPsVbk  
break; B*Xh
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} Unk+@$E&  
} &?pAt30K:  
catch(IOException e){e.printStackTrace ();} bm|8Jbsb&  
catch(Exception e){e.printStackTrace ();} qa#F}aGd  
^DJU99   
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Utility.log(nFileLength); 2?&ptN)`N  
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&WS%sE{p_  
return nFileLength; =i<(hgD  
} )^3655mb  
s47"JKf"  
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//保存下载信息（文件指针位置） l;i u`  
private void write_nPos() $RO=r90o  
{ gDIB'Y  
try{ )f|6=x4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); < ,n4|z)  
output.writeInt(nStartPos.length); WVFy ZpB  
for(int i=0;i<nStartPos.length;i++) }7^*%$  
{ jR:Fih-}  
// output.writeLong(nPos); yIP IA%dJ  
output.writeLong(fileSplitterFetch.nStartPos); 6FAP *V;  
output.writeLong(fileSplitterFetch.nEndPos); /zAx`H  
} $80/ub:R  
output.close(); Wb$bCR#?<  
} `UPmr50Wq  
catch(IOException e){e.printStackTrace ();} ;#  
catch(Exception e){e.printStackTrace ();} B 8,{jwB  
} ObnB6ShKi  
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b9jm=U  
//读取保存的下载信息（文件指针位置） wVX0!y6  
private void read_nPos() ^|z>NV5>  
{ v.J#d>tvf  
try{ gE#,QOy  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =0|e
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int nCount = input.readInt(); s6IuM )x  
nStartPos = new long[nCount]; *O2j<3CHf  
nEndPos = new long[nCount]; uLht;-`{n  
for(int i=0;i<nStartPos.length;i++) r6<}S(  
{ $tJJ >"  
nStartPos = input.readLong(); %hh8\5l.:  
nEndPos = input.readLong(); ~CscctD{;  
} ?U[AE -*  
input.close(); W@Wh@eSb;  
} z9ZAY!Zhq]  
catch(IOException e){e.printStackTrace ();} ;E_{Zji_e  
catch(Exception e){e.printStackTrace ();} -0Ek&"=Z^  
} wq#3f#3V  
9 R1]2U$|  
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private void processErrorCode(int nErrorCode) .Dz /MSl  
{ 8X5XwFf}  
System.err.println("Error Code : " + nErrorCode); #(G&%I A|;  
} ml2HA4X&$Y  
8V=o%[t  
D\JYa@*?.h  
//停止文件下载 ~1oD7=WN  
public void siteStop() C_/oORvK  
{ a6OT2B  
bStop = true; g*uO IF  
for(int i=0;i<nStartPos.length;i++) 1d6pQ9 N  
fileSplitterFetch.splitterStop(); |ouk;r24V  
,\i q'}i  
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} 8jk*N  
} .[! ^L  
//负责部分文件的抓取 |iI`p-L9  
**FileSplitterFetch.java OWzIea@  
*/ 82<
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package NetFox; pY@+.V`a  
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bB["Qd}
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import java.io.*; |9h[Q[m  
import java.net.*; "Y+`U  
([|M,P6e)U  
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public class FileSplitterFetch extends Thread { g`1i[Iu2  
N C&1l]  
4$rO,W/&0  
String sURL; //File URL |qD<h  
long nStartPos; //File Snippet Start Position s.U p<Rw  
long nEndPos; //File Snippet End Position o/xE O=AW  
int nThreadID; //Thread's ID pI4<` K  
boolean bDownOver = false; //Downing is over V& m\  
boolean bStop = false; //Stop identical ,>Q,0bVhH0  
FileAccessI fileAccessI = null; //File Access interface 4{_5z7o
dy  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %k~=iDk@  
{ iDA`pemmi&  
this.sURL = sURL; \[BnAgsF  
this.nStartPos = nStart; ?w+T_EH  
this.nEndPos = nEnd; Hs9uDGWp  
nThreadID = id; RB!g
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 Gu-Sv!4p  
} !Kis,e  
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/i<g>*82  
public void run() [3s~Z8 pP  
{ oUqNA|l T  
while(nStartPos < nEndPos && !bStop) ;AaF;zPV  
{ \n5,!,A  
)-mB^7uXGv  
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try{ 1/ a,7Hl  
URL url = new URL(sURL); *QLbrR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q^s$4q  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ugn"w E  
String sProperty = "bytes="+nStartPos+"-"; rr*IIG&.5  
httpConnection.setRequestProperty("RANGE",sProperty); E4{8 $:q=  
Utility.log(sProperty); \,WPFV  
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InputStream input = httpConnection.getInputStream(); ci!c7 ,'c  
//logResponseHead(httpConnection); `c icjA@~  
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b% F|VG  
byte[] b = new byte[1024]; \<5xf<{  
int nRead; o{
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B`vV[w?  
{ tNjrd}8s  
nStartPos += fileAccessI.write(b,0,nRead); !`u)&.t
7  
//if(nThreadID == 1) /N$T[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rO C~U85  
} Dbgw)n*2  
(b(iL\B$D=  
MKbW^:  
Utility.log("Thread " + nThreadID + " is over!"); \oi=fu=}*  
bDownOver = true; \ZC7vM"h  
//nPos = fileAccessI.write (b,0,nRead); <
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} 7L!k9"X`0F  
catch(Exception e){e.printStackTrace ();} h:|aQJG5  
} ZjzQv)gZ  
} "m!Cl-+u  
TPrwC~\B/  
6wGf47  
//打印回应的头信息 NTV0DkX  
public void logResponseHead(HttpURLConnection con) G B15  
{ bNXT*HOZb3  
for(int i=1;;i++) {h
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{ $I_aHhKt  
String header=con.getHeaderFieldKey(i); 0j*8|{|  
if(header!=null) WPPmh~:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6s6[sUf=l&  
Utility.log(header+" : "+con.getHeaderField(header)); qLR)>$  
else JLjx4B\  
break; zEu*q7  
} 4FYws5]$  
} NEX\+dtE~0  
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public void splitterStop() ~($h9*\  
{ 6`4=!ZfI  
bStop = true; j
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} smSUo/  
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,ujoGSx}  
} lOVsp#  
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uoF9&j5E@Z  
/* .uhP(  
**FileAccess.java n#4Ra+dD  
*//文件访问(定位，写) +~7@K{6q-  
package NetFox; #SO9e.yhI  
import java.io.*; y0Ag px  
K(hqDif*6  
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public class FileAccessI implements Serializable{ Ra.<D.  
<CeDIX t  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 &QvWT+]c'0  
RandomAccessFile oSavedFile; ^!=+$@<  
long nPos; *vht</?J  
Ur_~yX]Mo  
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public FileAccessI() throws IOException /']Gnt G.  
{ x6m21DWw  
this("",0); kYx|`-PA<r  
} 0n
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d]CRvzW  
public FileAccessI(String sName,long nPos) throws IOException ] OR]  
{ A07FjT5w8  
oSavedFile = new RandomAccessFile(sName,"rw");
9"&HxyOfX  
this.nPos = nPos; z[l17+v  
oSavedFile.seek(nPos); zDC-PHFHQ  
} ?!b}Ir<1j
 
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public synchronized int write(byte[] b,int nStart,int nLen) |NL$? %I  
{ XBCz\f  
int n = -1; \ 3ha  
try{ {,,w5/k^  
oSavedFile.write(b,nStart,nLen); 6:@tHUm  
n = nLen; uS3J^=>@(a  
} Wo\NX05-?  
catch(IOException e) ]^R;3kU4Q  
{ Jgb{Tl:r  
e.printStackTrace (); '\P6NszY~  
} )0YMi!&j`  
iN<Tn8-YH6  
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return n; *SLv$A  
} 5s`NR<|2L  
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} qpFFvZ W  
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/* q8`JRmt)H  
**SiteInfoBean.java PO1sVP.S  
*/ 8nW#Q<s  
package NetFox; 1Sr@$+VGO  
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public class SiteInfoBean { "4zTP!Ow  
}"E?#&^  
!Hxx6/  
private String sSiteURL; //Site's URL P'
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private String sFilePath; //Saved File's Path }hhDJ_I5M  
private String sFileName; //Saved File's Name :voQ#f=  
private int nSplitter; //Count of Splited Downloading File :k#Y|(  
}qRYXjS  
bR(rZu5  
public SiteInfoBean() H4MFTnJ{  
{//nSplitter的缺省值为5 d?.e
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//default value of nSplitter is 5 8W9kd"=U  
this("","","",5); Y 8EL  
} 8N'[)Jw  
5F18/:\n  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [g`
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{ MZv In ZS  
sSiteURL= sURL; h:}oUr8  
sFilePath = sPath; vg5i+ry<  
sFileName = sName; @/g%l1$`  
this.nSplitter = nSpiltter; aTxss:7]  
P?\IlziCB  
q{nNWvL  
} /q0[T{Wz$  
M|w;7P}  
c=0S]_  
public String getSSiteURL() E.R,'Y;x  
{ Ivmiz{Oii  
return sSiteURL; lQ {k  
} oYG9i=lZ  
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public void setSSiteURL(String value) qH1[BsOx  
{ %4*-BCP  
sSiteURL = value; 40w,:$  
} |Ah'KpL8W  
ZEYT17g]  
&!SdO<agZ  
public String getSFilePath() p8aGM-+40W  
{ <%Zg;]2H`  
return sFilePath; _Ryt|# y  
} G~5EAeG  
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public void setSFilePath(String value) O/Ub{=g  
{ G:7HL5u  
sFilePath = value; ry)g<OA  
} >4 4A  
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public String getSFileName() ^K. d|z  
{ XHKiz2Pc1  
return sFileName; j")#"& m  
} I]+xerVd  
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public void setSFileName(String value) 6O"?wN%$  
{ |Ii[WfFA|J  
sFileName = value; R9@Dd  
} E%8Op{zv_  
v'na{"  
$a.fQ<,\X  
public int getNSplitter() k<(G)7'gm  
{ HI&N&a9C  
return nSplitter; xMsSZ{j%5  
} .$&mWytw=  
50kjX}  
gT8Q:8f:  
public void setNSplitter(int nCount) z=%&?V
 
{ :59fb"^$  
nSplitter = nCount; ;\-f7!s  
} OCHjQc  
} Lu?MRF f  
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$23*:)&J4  
/* W}jel}:  
**Utility.java PIOG|E  
*/ %EV\nwn6  
package NetFox; \vwsRT 1  
5^lFksZ  
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public class Utility { ggn C #$  
>1uo5,wrF  
9bu}@#4*  
public Utility() K ?uHAm  
{ <5@VFRjc  
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W;L<zFFbU)  
} d?[gd(O  
0#Ivo<V  
//线程睡眠 8k~$_AT>u  
public static void sleep(int nSecond) @>:V?  
{ ["O/%6b9+  
try{ +\Uq=@  
Thread.sleep(nSecond); 4f~ c#0?  
} /Q]6"nY  
catch(Exception e) }OZut!_  
{ ]]Bqte  
e.printStackTrace (); l$_q#Kd  
} OeMI  
} vX?MB  
Lsu_f'p0  
//日志 >%6a$r~@  
public static void log(String sMsg) ]cQYSN7!SY  
{ ({&\~"  
System.err.println(sMsg); Y6W#uiqk  
} U)v){g3w)  
?`T0zpC  
|)5xmN]  
public static void log(int sMsg) Z01BzIsR  
{ S2+X/YeB  
System.err.println(sMsg); a%nksuP3  
} n1XJuc~  
} mH`K~8pRg  
l7T@<V  
j(xVbUa  
/* Budo9z_w  
**TestMethod.java mM#[XKOC<  
*/ 6&9}M Oc  
package NetFox; `|
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;D8175px;  
&[yW}uV<7  
public class TestMethod { 7=3'PfS  
|-)2 D=P  
3[{RH*nHD  
public TestMethod() S[zETRSG  
{ ///xx/weblogic60b2_win.exe 2.p?gRO  
try{ n3z]&J5fr  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Z-U-n/6I  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TKH!,Ow9A  
SiteFileFetch fileFetch = new SiteFileFetch(bean); qX9x#92  
fileFetch.start(); #3~hF)u&/  
} !=)b2}e/>  
catch(Exception e){e.printStackTrace ();} y@Gl'@-O  
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} 9M12|X\]8  
~7 w"$H8  
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public static void main(String[] args) (_0r'{`  
{ e'l@M$^  
new TestMethod(); q 3nF\Me0  
} (/i?Fd  
} ?+P D?c7  
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