http断点续传简单实现（java)

/* yX>K/68  
**SiteFileFetch.java yZY\MB/  
*/ qz_7%c]K[  
package NetFox; LBeF&sb6  
import java.io.*; 6q
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import java.net.*; w{8xpAqm  
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public class SiteFileFetch extends Thread { k=$TGqQY?  
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SiteInfoBean siteInfoBean = null; //文件信息Bean z_$%-6  
long[] nStartPos; //开始位置 Y(ykng  
long[] nEndPos; //结束位置 3DX*gsx(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 RMV/&85?y  
long nFileLength; //文件长度 Qp5VP@t  
boolean bFirst = true; //是否第一次取文件 g{)dP!}  
boolean bStop = false; //停止标志 ^LnTOdAE  
File tmpFile; //文件下载的临时信息 B3`5O[6  
DataOutputStream output; //输出到文件的输出流 {lzWrUGO  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @D[_}JE  
public SiteFileFetch(SiteInfoBean bean) throws IOException Y1\}5k{>  
{ &&8x%Pml  
siteInfoBean = bean; B:Oa}/H   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #P9~}JB3,  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /{J4:N'B>  
if(tmpFile.exists ()) d'gf
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{ F~vuM$+d  
bFirst = false; ,2oWWsC7  
read_nPos(); C3f' {}  
} ! I:%0
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else )AtD}HEv  
{ !?jrf] A@  
nStartPos = new long[bean.getNSplitter()]; M] %?>G  
nEndPos = new long[bean.getNSplitter()]; KK4`l}Fk:n  
} HyQJXw?A:  
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}  Mx?d  
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public void run() @i_FTN  
{ ?zMHP#i  
//获得文件长度 <NY^M!  
//分割文件 `
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//实例FileSplitterFetch $)i")=Hy  
//启动FileSplitterFetch线程 Et_bH%0  
//等待子线程返回 Lg+Ac5y}`  
try{ eQm
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if(bFirst) (8DC}kckE  
{ 2jItq2.>  
nFileLength = getFileSize(); 7F7{)L  
if(nFileLength == -1) S3%FHS  
{ -);Wfs  
System.err.println("File Length is not known!"); \:'/'^=#|  
} {z5--TogJ  
else if(nFileLength == -2) 7nTeP(M%  
{ B]wk+8SMY.  
System.err.println("File is not access!"); H2\;%
K 2  
} .VJMz4$]O  
else ZQsJL\x[UK  
{ 1=c\Rr9]  
for(int i=0;i<nStartPos.length;i++) ZU4nc3__  
{ {4}yKjW%z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); pj{`'; :g  
} R?|.pq/Ln  
for(int i=0;i<nEndPos.length-1;i++) _Ey9G  
{ VA>35w  
nEndPos = nStartPos[i+1]; {\"x3;3!6  
} ^7cGq+t  
nEndPos[nEndPos.length-1] = nFileLength; \ZFGw&yN  
} kx{{_w  
} ,4e:I.b  
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H5B:;g@  
//启动子线程 ,eW%{[g(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^ogt+6c  
for(int i=0;i<nStartPos.length;i++) sqwGsO$#  
{ jXx<`I+]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Yui3+}Ms  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), UgNu`$m+  
nStartPos,nEndPos,i); {X+3;&@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O, wJR  
fileSplitterFetch.start(); %P/Jq#FE.  
} S(lO(gY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )p0^zv{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); l`{\"#4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =`F(B  
nEndPos = " + nFileLength); ]=I@1B;_m  
// fileSplitterFetch[nPos.length-1].start(); +F` S>U  
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//等待子线程结束 P>C~ i:4n  
//int count = 0; .Iw AK/QS  
//是否结束while循环 qp}Cqi  
boolean breakWhile = false; O2E/jj  
~9]hV7y5C  
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while(!bStop) ||= )d&  
{ RD
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write_nPos(); o Q2Fjj  
Utility.sleep(500); ~d4 )/y  
breakWhile = true; Pb4X\9^  
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for(int i=0;i<nStartPos.length;i++) =F~S?y  
{ ~O0 $Suv  
if(!fileSplitterFetch.bDownOver) y/{fX(aV  
{ wC+u73599  
breakWhile = false; *[Tz![|  
break; nI-w}NQ  
} H3^},.  
} *boR`[Ond  
if(breakWhile) mt{nm[D!Xp  
break; KIf da
fRL  
pfDc9PMj  
c /HHy,  
//count++; ?k&Vy  
//if(count>4) L:j<c5  
// siteStop(); _x'6]f{n  
} ^z IW+:  
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System.err.println("文件下载结束！"); HGs $*  
} 2B[X,rL.pX  
catch(Exception e){e.printStackTrace ();} 6+|do+0Icg  
} ColV8oVnU  
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//获得文件长度 Y-
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public long getFileSize() R6Km\N  
{ m@2QnA[4  
int nFileLength = -1; wj^3N7_:w  
try{ V)HG(k  
URL url = new URL(siteInfoBean.getSSiteURL()); kR-SE5`Jk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Nho>f  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6:[dj*KGmT  
VU(v3^1"  
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int responseCode=httpConnection.getResponseCode(); ]Ji.Zk  
if(responseCode>=400) v5#jZ$<F  
{ uM IIYS  
processErrorCode(responseCode); t7Iv?5]N  
return -2; //-2 represent access is error HZC"nb}r4  
} x.!V^HQSN  
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String sHeader; F3@phu${  
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for(int i=1;;i++) |O\s
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{ iAEbu&XG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); p Z|V 3  
//Utility.log(in.readLine()); x_N'TjS^{  
sHeader=httpConnection.getHeaderFieldKey(i); (l~AV9!m:  
if(sHeader!=null) RUnSCOdX  
{ #uG%j  
if(sHeader.equals("Content-Length")) Eex~xiiV  
{ mI-]/:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {M4gF8(M  
break; UT~4x|b:O  
} [I,Z2G,Jb  
} OUPUixz2Z  
else ~S"+S/z/k  
break; ifMRryN4  
} wo;~7K  
} 7Jyy z,!5  
catch(IOException e){e.printStackTrace ();} X; \+<LE  
catch(Exception e){e.printStackTrace ();} a od-3"7[  
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Utility.log(nFileLength); )hn6sXo+  
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return nFileLength; }_M~2L?i  
} ~?Qe?hB  
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//保存下载信息（文件指针位置） Ct<udO  
private void write_nPos() _/s$ZCd  
{ p?%y82E  
try{ P:K5",)  
output = new DataOutputStream(new FileOutputStream(tmpFile)); z1 |TC  
output.writeInt(nStartPos.length); v!-/&}W)1  
for(int i=0;i<nStartPos.length;i++) 36&e.3/#  
{ 1Ti f{i,B  
// output.writeLong(nPos); F3[T.sf  
output.writeLong(fileSplitterFetch.nStartPos); ^+>laOzC`8  
output.writeLong(fileSplitterFetch.nEndPos); T\6dm/5  
} 2+N]PW\V  
output.close(); KEo,m  
} T"}5}6rSG  
catch(IOException e){e.printStackTrace ();} WtsFz*`)y  
catch(Exception e){e.printStackTrace ();} r4b 6 c  
} 7?!d^$B  
~]IOK$1F%  
93
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//读取保存的下载信息（文件指针位置） >-RQ]?^  
private void read_nPos() ~OYiq}g  
{ x*\Y)9Vgy  
try{ {=9,n\85#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); zOAd~E  
int nCount = input.readInt(); b;B%q$sntC  
nStartPos = new long[nCount]; A7Cm5>Y_S  
nEndPos = new long[nCount]; PFlNo` iO  
for(int i=0;i<nStartPos.length;i++) Gi|w}j_  
{ $t'MSlF  
nStartPos = input.readLong(); y4 #>X  
nEndPos = input.readLong(); "rALt~AX  
} vFzRg
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input.close(); ^qvZXb  
} 7dTkp!'X-  
catch(IOException e){e.printStackTrace ();} Fbr;{T .
 
catch(Exception e){e.printStackTrace ();} hn7# L  
} ~f&E7su-6+  
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private void processErrorCode(int nErrorCode) e9Wa<i8  
{ hE'-is@7  
System.err.println("Error Code : " + nErrorCode); 4$HhP,gL=  
} 3)t.p>VgO  
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v|_K/|  
//停止文件下载 EqkN3%IG  
public void siteStop() c)6m$5]  
{ fZGX}T<)p-  
bStop = true; .ljnDL/  
for(int i=0;i<nStartPos.length;i++) kUL'1!j7  
fileSplitterFetch.splitterStop(); RtkEGxw*^  
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} dK$XNi13.5  
} ('4_ xOb  
//负责部分文件的抓取 g>E LGG|Q  
**FileSplitterFetch.java TM_
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*/ 60^`JVGWH  
package NetFox; imhwY#D  
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import java.io.*; 6IN e@  
import java.net.*; U#7#aeI  
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public class FileSplitterFetch extends Thread { S1T"Z{$  
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String sURL; //File URL XAD- 'i  
long nStartPos; //File Snippet Start Position Si4!R+
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long nEndPos; //File Snippet End Position #ZUI)9My@  
int nThreadID; //Thread's ID p#ZCvPE;uH  
boolean bDownOver = false; //Downing is over CCs%%U/=  
boolean bStop = false; //Stop identical nI?[
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FileAccessI fileAccessI = null; //File Access interface :I.mGH!^  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Pa>AWOG'  
{ \i>?q  
this.sURL = sURL; Fk&c=V;SU  
this.nStartPos = nStart; x /(^7#u,  
this.nEndPos = nEnd; W
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nThreadID = id; k&M;,e3v6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 `z}?"BW|  
} ]? c B:}  
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public void run() xWH.^o,"  
{ ?>9/#Nv  
while(nStartPos < nEndPos && !bStop) rET\n(AJ  
{ x;O[c3I  
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try{ ^x]r`b  
URL url = new URL(sURL); :I]Mps<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B9_X;c  
httpConnection.setRequestProperty("User-Agent","NetFox"); X;+sUj8  
String sProperty = "bytes="+nStartPos+"-"; ~Py`P'+  
httpConnection.setRequestProperty("RANGE",sProperty); ;DQ ZT  
Utility.log(sProperty); wA ,6bj  
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InputStream input = httpConnection.getInputStream(); O
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//logResponseHead(httpConnection); mX"oW_EK  
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byte[] b = new byte[1024]; n1ZbRV  
int nRead; )EPjAv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^'MT0j  
{ 93>jr<A  
nStartPos += fileAccessI.write(b,0,nRead); .|KyNBn  
//if(nThreadID == 1) 1/B>XkCJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kM l+yli3c  
} G<zwv3  
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AG nxYV"p  
Utility.log("Thread " + nThreadID + " is over!"); f3l&3hC  
bDownOver = true; fivw~z|[@  
//nPos = fileAccessI.write (b,0,nRead); zy?|ODM  
} 3@_xBz,I.  
catch(Exception e){e.printStackTrace ();} 0(}t8lc  
} f].h^~.q  
} PA{PD.4Du  
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//打印回应的头信息 KJUH(]>F  
public void logResponseHead(HttpURLConnection con) x M/+L:_<  
{ Ys9[5@7  
for(int i=1;;i++) T9|m7  
{ 79rD7D&g  
String header=con.getHeaderFieldKey(i); .^33MWu6  
if(header!=null) aH(J,XY  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *\a4wZ6<3  
Utility.log(header+" : "+con.getHeaderField(header)); ah$b[\#C  
else un"Gozmt5  
break; #6aW9GO  
} 4}baSV  
} ?T8}K>a   
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public void splitterStop() dh\'<|\K  
{ G^|:N[>B  
bStop = true; =+-UJo5  
} se2!N:|R!G  
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|-67\p]  
} <]t%8GB2V  
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/* wo{gG?B  
**FileAccess.java `:fZ)$sY  
*//文件访问(定位，写) A1$T
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package NetFox; ] )\Pqn(  
import java.io.*; \~mT] '5  
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public class FileAccessI implements Serializable{ cxC6n%!
;y  
 @tnz]^V  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 K:[F%e  
RandomAccessFile oSavedFile; epe)a  
long nPos; CI0C1/:@  
|kg7LP3(8,  
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public FileAccessI() throws IOException SYJD?&C;  
{ ?pmHFlx  
this("",0); VQt0 4?  
} 3,3N^nSD  
h 0Q5-EA  
9d659iC  
public FileAccessI(String sName,long nPos) throws IOException ^98~U\ar  
{ UYJZYP%r  
oSavedFile = new RandomAccessFile(sName,"rw"); 13=AW  
this.nPos = nPos; kd(8
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oSavedFile.seek(nPos); `wEb<H  
} oxA<VWUNT
 
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public synchronized int write(byte[] b,int nStart,int nLen) e{K 215  
{ ;7V%#-  
int n = -1; L|7R9+ZG  
try{ bl;1i@Z*M  
oSavedFile.write(b,nStart,nLen); Z]Cq3~l  
n = nLen; I-*S&SiXjI  
} BhGu!Y6f  
catch(IOException e) 6,"Q=9k4[  
{ s~g *@K>+  
e.printStackTrace (); n5NsmVW\x  
} hd<c&7|G'  
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return n; !9
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} $k%2J9O  
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} _C?hHWSf"  
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/* Rtl"Ub@HV  
**SiteInfoBean.java (m/G(wg  
*/ WX?IYQ+  
package NetFox; k$R-#f;  
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public class SiteInfoBean { $a"Oc   
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1};Stai'  
private String sSiteURL; //Site's URL 9}<ile7^  
private String sFilePath; //Saved File's Path zP8lN(LA  
private String sFileName; //Saved File's Name 5x4yyb'  
private int nSplitter; //Count of Splited Downloading File Id .nu/  
pJ"qu,w  
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public SiteInfoBean() P@Oo$ o  
{//nSplitter的缺省值为5 W+?4jwqw  
//default value of nSplitter is 5 Ckuh:bs  
this("","","",5); <uw9DU7G  
} x2\qXN/R  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) K`zdc`/  
{ m@v\(rT.  
sSiteURL= sURL; IK=a*}19L  
sFilePath = sPath; |&)dh<  
sFileName = sName; h2]P]@nW;W  
this.nSplitter = nSpiltter; SsDmoEeB[  
c9 _rmz8  
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} :>f )g  
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public String getSSiteURL() ?X<eV1a   
{ Z
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return sSiteURL; 04P}-L,  
} s)D;a-F  
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public void setSSiteURL(String value) <^jQo<kU  
{ e2oa($9  
sSiteURL = value; EUX\^c]n  
} O;jrCB  
aSQ#k;T[  
$Sip$\+*  
public String getSFilePath() 2-v%`fA  
{ !PQ<04jA!  
return sFilePath; y/7\?qfTk  
} 8dIgjQX|  
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=  
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public void setSFilePath(String value) vr6w^&[c^  
{
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sFilePath = value; p]+Pkxz]'  
} hD!7Cl Q  
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6 V=9M:  
public String getSFileName() rw JIx|(  
{ Ioa$51&  
return sFileName; jLm ;ty2;  
}
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public void setSFileName(String value) vX
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{ ;dgp+  
sFileName = value; 0GC
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} -C]5>& W  
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:':s@gqr  
public int getNSplitter() 9qzHS~l  
{ 0 /U{p,r6`  
return nSplitter; Kis
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} h3 }OX{k  
?%[@Qb=2  
'7@zGk##(  
public void setNSplitter(int nCount) Iit;F  
{ ?IT*:A]E  
nSplitter = nCount; . 3T3EX|G  
} ( ^Nz9{  
} )Y{L&A  
=m#?neop  
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/* &d^m 1  
**Utility.java S;#'M![8  
*/ =dYqS[kJW  
package NetFox; k,+0u/I  
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public class Utility { s9DYi~/,  
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public Utility() >!1-lfa8
 
{ vV-`jsq20H  
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} Z,Dl` w  
M!D3}JRm  
//线程睡眠 Y&Z.2>b
 
public static void sleep(int nSecond)
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{ bP&]!jZ  
try{ RQ" ,3.R==  
Thread.sleep(nSecond); d|Lj~x|  
} ^o&. fQ*  
catch(Exception e) Z o(rTCZX  
{ e1Hgw[l`  
e.printStackTrace (); .Rs^YZF  
} H8}oIA"b  
} @Qt{jI!  
=^,m` _1  
//日志 N2<!}Eyu  
public static void log(String sMsg) _g"<UV*H  
{ i2SR{e8:GF  
System.err.println(sMsg); 5MJS ~(  
} #BH*Z(  
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R`E~ZWC4V  
public static void log(int sMsg) $suzW;{#  
{ :nOFR$W  
System.err.println(sMsg); pG;U2wE  
} &E5g3lf  
} t&e{_|i#+  
}a(dyr`S  
<bEbweQrgm  
/* N6i Q8P-  
**TestMethod.java R%[ c;i  
*/ ,/|T-Ka
 
package NetFox; m#\dSl}  
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public class TestMethod { ((M>s&\y*Y  
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d<P\&!R(  
public TestMethod() NyNXP_8  
{ ///xx/weblogic60b2_win.exe ' %o#q6O  
try{ :&."ttf=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); tf`^v6m%]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ds[|   
SiteFileFetch fileFetch = new SiteFileFetch(bean); qF;|bF  
fileFetch.start(); j*r{2f4Rt  
} !'*-$e  
catch(Exception e){e.printStackTrace ();} c(s.5p ^  
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} WCixKYq  
g{&ui.ml&  
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public static void main(String[] args) D2~*&'4y  
{ #!+:!_45  
new TestMethod(); 3L}A3de'  
} St*h>V6  
} PB\x3pV!}  
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