http断点续传简单实现（java)

/* 1dh_"/  
**SiteFileFetch.java >gM|:FG  
*/ 767xCP  
package NetFox; .%_scNP  
import java.io.*; ks<gSCB  
import java.net.*; 5|f[evQj<S  
5<w"iqZ\?N  
6[,*2a8  
public class SiteFileFetch extends Thread { +6@".<  
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SiteInfoBean siteInfoBean = null; //文件信息Bean dFD0l?0N  
long[] nStartPos; //开始位置 Iz,a Hrq  
long[] nEndPos; //结束位置 =;!C7VS  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 H>AQlO+J  
long nFileLength; //文件长度 Pwf2dm$,+  
boolean bFirst = true; //是否第一次取文件 cG1-.,r  
boolean bStop = false; //停止标志 2c@4<kyfP  
File tmpFile; //文件下载的临时信息 YqX/7b+  
DataOutputStream output; //输出到文件的输出流 XFeHkU`C  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） *L7 ZyERs  
public SiteFileFetch(SiteInfoBean bean) throws IOException " NnUu8x  
{ eyBLgJt8P  
siteInfoBean = bean; b<};"H0a  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); sCU<1=   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?VS(W  
if(tmpFile.exists ()) :"7V,UP @  
{ -'3~Y 2#  
bFirst = false; ag^EH"%zw  
read_nPos(); +!Q<gWb  
} 5VdF^.:u  
else
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{ DcaVT]"  
nStartPos = new long[bean.getNSplitter()]; [}q6bXM*  
nEndPos = new long[bean.getNSplitter()]; jR`q  y<  
} s9svuFb  
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} LnP={s

 
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public void run() @N,dA#  
{ pYIm43r H  
//获得文件长度 :S'P lH  
//分割文件 iV;X``S  
//实例FileSplitterFetch 4<g,L;pUU  
//启动FileSplitterFetch线程 bzD <6Z  
//等待子线程返回 oV"#1
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try{ tQE=c7/M  
if(bFirst) |LA@guN  
{ k2DT+}u7G  
nFileLength = getFileSize(); k"X<gA  
if(nFileLength == -1) XMo#LS  
{ qE?*:$  
System.err.println("File Length is not known!"); Bc3(xI'>J  
} ovJwor  
else if(nFileLength == -2) HLm6BtE  
{  Xr'Y[E[  
System.err.println("File is not access!"); cnJ(Fv_F$  
} I?c "\Fe  
else mTXeIng?  
{ EwDF
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for(int i=0;i<nStartPos.length;i++) <nDuN*|  
{ 9NXf~-V-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); x&>zD0\ :\  
} [yj-4v%u`  
for(int i=0;i<nEndPos.length-1;i++) M ^gva?{  
{ WgX9k J  
nEndPos = nStartPos[i+1]; @%Y$@Qb{  
} Zn{,j0;  
nEndPos[nEndPos.length-1] = nFileLength; yneIY-g(p  
} 6iAHus-  
} d$
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//启动子线程 ]M%kt+u!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; NKyaR_q`  
for(int i=0;i<nStartPos.length;i++) vzDoF0Ts*p  
{ !Ab4'4f  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z,~Bz@5`"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), XIQfgrGZ  
nStartPos,nEndPos,i); \$;Q3t3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \/=w\T
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fileSplitterFetch.start(); ^f][;>c  
} sXe=4`O  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +M@p)pyu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ErZYPl  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", rBNl%+ sB  
nEndPos = " + nFileLength); Op''=Ar#sh  
// fileSplitterFetch[nPos.length-1].start(); {|dU
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rqa?A}'  
//等待子线程结束 dC&{zNG  
//int count = 0; Tgxxm  
//是否结束while循环 gZkjh{rQ  
boolean breakWhile = false; S#gIfb<D  
Z?@1X`@  
}~/u%vI@M5  
while(!bStop) ~\4`tc  
{ >wsS75n1  
write_nPos(); dt -EY  
Utility.sleep(500); s^O>PEX&<I  
breakWhile = true; @log=^  
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for(int i=0;i<nStartPos.length;i++) +[W_Jz  
{ "Yh[-[,  
if(!fileSplitterFetch.bDownOver) vpTYfE  
{ T
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breakWhile = false;
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break; sf""
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} LojE
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} 0LQ|J(u  
if(breakWhile) W=Y?_Oz  
break; Z]Zs"$q@  
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//count++; &RSUB;ymL  
//if(count>4) s]=bg+v?j  
// siteStop(); E05RqnqBn0  
} '3n?1x  
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System.err.println("文件下载结束！"); %+>t @F,GM  
} t,CC~  
catch(Exception e){e.printStackTrace ();} {'(1c)q>  
} DM*GvBdR  
)Fa

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//获得文件长度 u<}PcI.  
public long getFileSize() :Fvd?[  
{ *ud"?{)Z  
int nFileLength = -1; y2XeD=_'  
try{ dV~yIxD}C*  
URL url = new URL(siteInfoBean.getSSiteURL()); V={`k$p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O(P ,!  
httpConnection.setRequestProperty("User-Agent","NetFox"); -Odk'{nW  
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int responseCode=httpConnection.getResponseCode(); ,{KjVv<  
if(responseCode>=400) 9!aQ@ J^  
{ {{3n">s}:  
processErrorCode(responseCode); M=HP!hn  
return -2; //-2 represent access is error QH?}uX'x)G  
} !a(#G7zA  
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String sHeader; Obd};&6Q  
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for(int i=1;;i++) Y<A593  
{ Wa/&H$d\u@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Iy2KOv@a5  
//Utility.log(in.readLine()); LTSoo.dE  
sHeader=httpConnection.getHeaderFieldKey(i); 5LPyPL L  
if(sHeader!=null)
 :RYh@.  
{ cqr4P`Oj  
if(sHeader.equals("Content-Length")) Z$8X1(o  
{ f/_RtOSw  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [CCj5N1/  
break; 0Q2P"1>KT/  
} 6b-

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} 6?"k&O  
else %J_`-\)"{~  
break; W?*]'0  
} p@/i e@DX  
} FIB 9W@oao  
catch(IOException e){e.printStackTrace ();} 3EM=6\#q  
catch(Exception e){e.printStackTrace ();} Rh:@@4<  
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Utility.log(nFileLength); f*+eu@  
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return nFileLength; ;:w?&4  
} **zh>Y}6  
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//保存下载信息（文件指针位置） ypoJ4EZ(  
private void write_nPos() w(sD}YA)  
{ AWp{n  
try{ LI>tN R~  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q
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output.writeInt(nStartPos.length); qqm7p ,j  
for(int i=0;i<nStartPos.length;i++) mP1EWh|  
{ S 1%/ee3  
// output.writeLong(nPos); y~&R(x~w  
output.writeLong(fileSplitterFetch.nStartPos); \= M*x  
output.writeLong(fileSplitterFetch.nEndPos); l.DC20bs  
} s^ t1T&  
output.close(); Z3ucJH/)V  
} kc0YWW Q-:  
catch(IOException e){e.printStackTrace ();} {=(GY@yU/  
catch(Exception e){e.printStackTrace ();} yv.UNcP?  
} tMWDKatb  
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//读取保存的下载信息（文件指针位置） XO*|P\#^  
private void read_nPos() CM; r\,o  
{ E~=`Ac,G2  
try{ BE54^U  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); sqAZjfy@  
int nCount = input.readInt(); qOyg&]7  
nStartPos = new long[nCount]; ,ux?wa+  
nEndPos = new long[nCount]; IF<?TYy=3B  
for(int i=0;i<nStartPos.length;i++) NJEubC?  
{ X8TwMt  
nStartPos = input.readLong(); e 1W9Z $m  
nEndPos = input.readLong(); Q4gsOxP  
} Up61Xn  
input.close(); -}liG  
} 83"Vh$
&  
catch(IOException e){e.printStackTrace ();} J#tGQO  
catch(Exception e){e.printStackTrace ();} wSTy2Oyo;  
} eOZ0L1JM!  
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private void processErrorCode(int nErrorCode) jU1([(?"  
{ g\ r%A  
System.err.println("Error Code : " + nErrorCode); 7$ vs X  
} g]^@bxdg  
3BBw:)V  
JXG%Cx!2}  
//停止文件下载 %P!
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public void siteStop() y{>d&M|  
{ k"*A@  
bStop = true; z1LN|+\}  
for(int i=0;i<nStartPos.length;i++) K{eq'F5M  
fileSplitterFetch.splitterStop(); o6JCy\Bx  
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} _#6_7=g@s6  
} sdk%~RN0T  
//负责部分文件的抓取 1#KE4(  
**FileSplitterFetch.java |7$Fr[2d  
*/ {+CW_ce  
package NetFox; D%L}vugxK  
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import java.io.*; -+^E5  
import java.net.*; 3l
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public class FileSplitterFetch extends Thread { ?`wO \>y  
8UH c,np  
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String sURL; //File URL  T06BrX  
long nStartPos; //File Snippet Start Position J$'Q3k  
long nEndPos; //File Snippet End Position =og5Mh,  
int nThreadID; //Thread's ID V`F]L^m=L  
boolean bDownOver = false; //Downing is over ~s#vP<QHa  
boolean bStop = false; //Stop identical WCK;r{p%I  
FileAccessI fileAccessI = null; //File Access interface %Vf3r9 z  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException u\LbPk  
{ 8ZmU
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this.sURL = sURL; N~c Y~a  
this.nStartPos = nStart; !E
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this.nEndPos = nEnd; CC?L~/gPN  
nThreadID = id; mMp(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 r]GG9si  
} dD%Sbb  
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public void run() :Q~Rb<']{x  
{ bFV
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while(nStartPos < nEndPos && !bStop) PVK. %y9  
{ ]+C;C  
2)_Zz~P^f  
eouxNw}F1  
try{ 0keqtr  
URL url = new URL(sURL); lCyBdY9n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %(f&).W  
httpConnection.setRequestProperty("User-Agent","NetFox"); [(*ObvEF  
String sProperty = "bytes="+nStartPos+"-"; l1<]pdLTR  
httpConnection.setRequestProperty("RANGE",sProperty); H1!u1k1nl  
Utility.log(sProperty); n'WhCrW  
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InputStream input = httpConnection.getInputStream(); OrN~ Y#D  
//logResponseHead(httpConnection); R 4= ~  
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byte[] b = new byte[1024]; AeQIsrAHE  
int nRead; #CRAQ#:45(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @ V_@r@A  
{ 1[? xU:;9  
nStartPos += fileAccessI.write(b,0,nRead); \{g;|Z1  
//if(nThreadID == 1) F.N4Q'2Z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @<^_ _."  
} W zKaLyM  
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Utility.log("Thread " + nThreadID + " is over!"); EWU(Al T  
bDownOver = true; '[T#d!T  
//nPos = fileAccessI.write (b,0,nRead); do-mkvk  
} G1:*F8q  
catch(Exception e){e.printStackTrace ();} <'Ppu  
} Y6&B%t<b
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} ('9LUFw\  
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//打印回应的头信息 :!fP~(R'm  
public void logResponseHead(HttpURLConnection con) bwr}Ge  
{ O8!> t7x  
for(int i=1;;i++) nVSuvq|S  
{ #z(
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String header=con.getHeaderFieldKey(i); Z`W@Od$f  
if(header!=null) Z'u:Em  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); s#nd:$p3  
Utility.log(header+" : "+con.getHeaderField(header)); =Wgz\uGJ  
else }mhD2'E  
break; Q?1' JF!G  
} Eps2  
} r@|{mQOxa  
f^EDiG>b`  
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public void splitterStop() sF+mfoMtG  
{ T({]fc!c  
bStop = true; i&%/]Nq  
} v?9  
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} qaj~q(j~C  
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/* O<:"Irq\qr  
**FileAccess.java 0/vmj,&B(  
*//文件访问(定位，写) C}7c:4c  
package NetFox; oD@~wcMIT0  
import java.io.*; 3ZAPcpB2  
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public class FileAccessI implements Serializable{ Vk#wJ-  
(,i&pgVZ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 O6P{+xj$  
RandomAccessFile oSavedFile; |z5`h  
long nPos; _a?(JzLw5  
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public FileAccessI() throws IOException ]P5|V4FXo  
{
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this("",0); jMH=lQ+8  
} |KC!6<}T~9  
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public FileAccessI(String sName,long nPos) throws IOException ~0^d-,ZD5  
{ ]W7e2:Hra  
oSavedFile = new RandomAccessFile(sName,"rw"); JIA'3"C  
this.nPos = nPos; {FrcpcrQa  
oSavedFile.seek(nPos); '/ >7pB  
} -q8R'?z[  
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]{/1F:bcQ  
public synchronized int write(byte[] b,int nStart,int nLen) 8vuA`T!~G  
{ \'BA}v &/  
int n = -1; 15/lX  
try{ _tJm0z!  
oSavedFile.write(b,nStart,nLen); y\M Kd[G7  
n = nLen; a@ub%laL Z  
} 9k`}fk\M  
catch(IOException e) >7[o=!^:4  
{ &`9p.  
e.printStackTrace (); WqHsf1?N  
} X}W4dpU,  
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return n; !qQB}sAf  
} -fB;pS,  
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} 5xsGSoa+  
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/* k,kr7'Q  
**SiteInfoBean.java MKr)6PG,  
*/ s9p~  
package NetFox; ^tFbg+.  
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public class SiteInfoBean { 4^jIV!V  
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private String sSiteURL; //Site's URL QR#L1+Hn  
private String sFilePath; //Saved File's Path qTA,rr#p0  
private String sFileName; //Saved File's Name Z +vT76g3  
private int nSplitter; //Count of Splited Downloading File \mIm}+!H  
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public SiteInfoBean() ; { MK  
{//nSplitter的缺省值为5 AB1.l hR  
//default value of nSplitter is 5 8F;f&&L"y  
this("","","",5); VxKD>:3c  
} ayR;|S  
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@7fx0I'n  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [l7 G9T}/[  
{ @_L:W1[  
sSiteURL= sURL; ] C&AU[U*  
sFilePath = sPath; 0Gr^#`  
sFileName = sName; M#?^uu'  
this.nSplitter = nSpiltter; H({Y  
)}[:.Zg,3/  
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} @'ln)RT,  
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 uK_R#^  
public String getSSiteURL() 1yg5d9  
{ r@.3.Q  
return sSiteURL; =ll{M{0Q]!  
} O*:8gu'Y2  
"4,Zox{^  
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public void setSSiteURL(String value) nG+L'SmI  
{ iax6o+OG|  
sSiteURL = value; >,#73
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} bTrQ(qp  
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public String getSFilePath() VZRM=;V  
{ "92Z"I~1  
return sFilePath; -eA3o2'  
} 2o\GU  
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public void setSFilePath(String value) 49;2tl;F  
{ 3H'+7
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sFilePath = value; Bv)4YU
 
} .AzGPcJY  
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public String getSFileName() 9W~
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{ F9Bj$`#)  
return sFileName; :6
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} 2S{IZ]  
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2Y2J)5,  
public void setSFileName(String value) eL7rX"!  
{ +TR#  
sFileName = value; T5jZd@VT,  
} !N::1c@C  
N-+`[8@(P<  
7fB:wPlG;  
public int getNSplitter() A)X 'We  
{ BWz7m9T  
return nSplitter; !{L6 4qI  
} 0tzMu#  
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d
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public void setNSplitter(int nCount) <XfCQq/  
{ SLiQHWw*J  
nSplitter = nCount; 0k];%HV|  
} n<x NE%  
} m9Z3q ;  
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/* x7s75  
**Utility.java b;[u=9ez  
*/ F
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package NetFox; L%7?
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public class Utility { )eFq0+6*)  
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public Utility() 8^H <dR  
{ }b#KV?xgW  
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} #nL&x3  
!50Fue^JM  
//线程睡眠 vM}oxhQ$n  
public static void sleep(int nSecond) +^c;4-X 0  
{ ]<0|"NL  
try{ S*o%#ZJN  
Thread.sleep(nSecond); hr8v O"tZN  
} rZ~.tT|(  
catch(Exception e) Xm7Nr#  
{ cD6$C31Y]  
e.printStackTrace (); O;qerE?i`  
} cTKj1)!z?X  
} eeuT
f  
 \|Qx`-  
//日志 HNA/LJl[VU  
public static void log(String sMsg) _RFTm.9&  
{ gE/O29Y  
System.err.println(sMsg); )w8h2=l  
} 4Lx#5}P  
nQc]f*  
uvK1gJrA)  
public static void log(int sMsg) "8U
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{ CQo<}}-o  
System.err.println(sMsg); fPs'A  
} ta*B#2D>  
} hsVf/%  
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/* b!Q|0X.?  
**TestMethod.java IYq)p /  
*/ slV+2b  
package NetFox; nf5Ld"|%9  
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public class TestMethod { M`$s dZ"  
-X~VXeg  
vMsb@@O\\  
public TestMethod() F:.rb Ei  
{ ///xx/weblogic60b2_win.exe 6,sZo!G  
try{ AF4:v<EN  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )W!8,e+%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >A#wvQl7   
SiteFileFetch fileFetch = new SiteFileFetch(bean); GZ#6}/;b  
fileFetch.start(); oagxTFh8~  
} ZPWY0&9  
catch(Exception e){e.printStackTrace ();} =PiDZS^"  
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} dUOvv/,FZT  
~y%8uHL:  
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public static void main(String[] args) W$7db%qFx  
{ wSHE~Xx  
new TestMethod(); $v?+X20  
} 5|!x0H;  
} [vkz<sL"  
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