http断点续传简单实现（java)

/* p/VVb%  
**SiteFileFetch.java KNd<8{'.  
*/ )Hmf=eoc  
package NetFox; 0V(}Zj>  
import java.io.*; Zx_^P:rL  
import java.net.*; "O<ETHd0  
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public class SiteFileFetch extends Thread { JHvev,#4  
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SiteInfoBean siteInfoBean = null; //文件信息Bean wN4#j}C  
long[] nStartPos; //开始位置 ]lBCK  
long[] nEndPos; //结束位置 dp'[I:X  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ceJi|`F  
long nFileLength; //文件长度 ?X6}+  
boolean bFirst = true; //是否第一次取文件 ]4en|Aq  
boolean bStop = false; //停止标志 n"6L\u  
File tmpFile; //文件下载的临时信息 XDPgl=~  
DataOutputStream output; //输出到文件的输出流 (H !iK,R  
l[ $bn!_e  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） w,FPL&{  
public SiteFileFetch(SiteInfoBean bean) throws IOException &4S2fWx  
{ L}Y.xi  
siteInfoBean = bean; jJNCNH*0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); y"q>}5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _7<{+Zzm  
if(tmpFile.exists ()) jxkjPf?  
{ s{yw1:  
bFirst = false; %}VH5s9\  
read_nPos(); D4[t^G;J  
} {ptHk<K:)  
else @e GBF Ns  
{ >VkBQM-%  
nStartPos = new long[bean.getNSplitter()]; DJ:'<"zH7  
nEndPos = new long[bean.getNSplitter()]; 0~^RHb.NA8  
} G_S>{<[  
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} M lR~`B}m  
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public void run() +K`A2&F9  
{ ~s'tr&+  
//获得文件长度 !EhKg)y=  
//分割文件 -m%`Di!E  
//实例FileSplitterFetch @i;)`k5b  
//启动FileSplitterFetch线程 ?e<2'\5v  
//等待子线程返回 j/d}B
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try{ y]fI7nu&  
if(bFirst) gE#'Zv{7  
{ yQN{)rv  
nFileLength = getFileSize(); ^D$|$=|DH  
if(nFileLength == -1) \xCCJWek  
{ h&$h<zL[  
System.err.println("File Length is not known!"); yEI@^8]s  
} ezp%8IZ;  
else if(nFileLength == -2) ^0OP&s;"  
{ bTaKB-  
System.err.println("File is not access!"); }Ze*/p-  
} LD}~]  
else -9i7Ja  
{ sE6>JaH  
for(int i=0;i<nStartPos.length;i++) *c94'Tcl  
{ *kl  :/#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); $}gMJG  
} K%? g6j  
for(int i=0;i<nEndPos.length-1;i++) jfY7ich  
{ Ey|_e3Lf[  
nEndPos = nStartPos[i+1];  Qw}1q!89  
} TB!I  
nEndPos[nEndPos.length-1] = nFileLength; -$Hu$Y}>  
} wgS,U}/i  
} yQD>7%x  
SXm%X(JU  
RDp  
//启动子线程 (O5Yd 6u  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *{
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for(int i=0;i<nStartPos.length;i++) ZP<<cyY  
{ .+/d08]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d}[cX9U/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), v\U
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nStartPos,nEndPos,i); 4V')FGB$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Dp ](?Yr  
fileSplitterFetch.start(); rR> X<  
}  S=(O6+U  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o[Jzx2A<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,|({[9jA  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", kO}&Oi,?  
nEndPos = " + nFileLength); @owneSD qN  
// fileSplitterFetch[nPos.length-1].start(); }oRBQP^&K  
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m0"K^p  
//等待子线程结束 TmQIpeych  
//int count = 0; MIrx,d  
//是否结束while循环 rGyAzL]  
boolean breakWhile = false; P2-&Im`+  
{_O!mI*  
.:r~?$(  
while(!bStop) ?dgyi4J?=`  
{ L=4+rshl!_  
write_nPos(); !mmMAsd,  
Utility.sleep(500); (90/,@66l  
breakWhile = true; _fHml  
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for(int i=0;i<nStartPos.length;i++) <W"W13*j!  
{ Fm
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if(!fileSplitterFetch.bDownOver) br[iRda@  
{ Rm} ym9  
breakWhile = false; ^}_Ka//k  
break; WTJ 0Q0U  
} hzqJ!  
} U#` e~d t<  
if(breakWhile) mLX/xM/T?/  
break; hy5[ L`B  
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//count++; t~) P1Lof\  
//if(count>4) BNu >/zGpB  
// siteStop(); tJ\ $
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} a#YK1n[!  
$F2Uv\7=  
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System.err.println("文件下载结束！"); c{1;x)L  
} ^,>w`8  
catch(Exception e){e.printStackTrace ();} o|kykxcq  
} P0m3IH)  
xh;V4zK@`  
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//获得文件长度 FZr/trP~  
public long getFileSize() 9zu;OK%  
{ :!%VSem  
int nFileLength = -1; HZyA\FS  
try{ -K64J5|b7  
URL url = new URL(siteInfoBean.getSSiteURL()); 2B ]q1>a!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); oJ74Mra  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3
5<A:jKS  
r )F;8
(  
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int responseCode=httpConnection.getResponseCode(); j[G`p^ul  
if(responseCode>=400) }aZuCe_  
{ k?+ 7%A]  
processErrorCode(responseCode); l|P"^;*zq  
return -2; //-2 represent access is error Yj/afn(Jt  
} p)y5[HX  
53HA6:Q[  
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String sHeader; ~||0lj.D  
6hxZ5&;(*  
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for(int i=1;;i++) v/+ <YU  
{ oP&/>GmXL  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); z5
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//Utility.log(in.readLine()); (Rw<1q`,  
sHeader=httpConnection.getHeaderFieldKey(i); `q^#u  
if(sHeader!=null) L:$4o  
{ ge~@}&#iO@  
if(sHeader.equals("Content-Length")) *]$B 9zVs!  
{ v"USD<   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )9]a  
break; ".?4`@7F\  
} [C'bfX5HB5  
} n|(lPbD  
else wPlM= .Hq?  
break; jm}CrqU  
} Y{YbKKM  
} 2HE@!*z9H  
catch(IOException e){e.printStackTrace ();} Pe`(9&iT.  
catch(Exception e){e.printStackTrace ();} C8U3+ s  
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Utility.log(nFileLength); AI|vL4*Xd  
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return nFileLength; smP4KC"I(d  
} VmS_(bM  
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&N~Eu-@b  
//保存下载信息（文件指针位置） Q_5l.M/9]  
private void write_nPos() 82r8K|L.<y  
{ -$Oh.B`i  
try{ c4Ebre-Oa  
output = new DataOutputStream(new FileOutputStream(tmpFile)); <DF3!r  
output.writeInt(nStartPos.length); qE[S>/R"  
for(int i=0;i<nStartPos.length;i++) u,^CFws_  
{ l2D*b93  
// output.writeLong(nPos); OM86C  
output.writeLong(fileSplitterFetch.nStartPos); Y t(D  
output.writeLong(fileSplitterFetch.nEndPos); lA
^1}  
} l/.{F;3F  
output.close(); OUX7 *_  
} uYh!04u  
catch(IOException e){e.printStackTrace ();} 02;jeZ#z  
catch(Exception e){e.printStackTrace ();} akj<*,  
} a=z] tTs4  
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e &6
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//读取保存的下载信息（文件指针位置） kK6OZhLH  
private void read_nPos() E/;t6&6  
{ ;tOsA
#  
try{ {{G)Ry*pb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); H>~CL  
int nCount = input.readInt(); |
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nStartPos = new long[nCount]; jLAEHEs  
nEndPos = new long[nCount]; z0z@LA4k6@  
for(int i=0;i<nStartPos.length;i++) mQ"~x]  
{ "Ep"$d  
nStartPos = input.readLong(); -+R,="nRQ  
nEndPos = input.readLong(); vObZ|>.J~O  
} "+HJ/8Dd1  
input.close(); 70'OS:J=\  
} LEb$Fd  
catch(IOException e){e.printStackTrace ();} s,z~qL6&  
catch(Exception e){e.printStackTrace ();} 19!?oeOU  
} *1|7%*!8  
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private void processErrorCode(int nErrorCode) 9vI~vl l  
{ w"hd_8cO  
System.err.println("Error Code : " + nErrorCode); BU`X_Z1)  
} -f+#j
=FX  
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//停止文件下载 kiTC)S=])  
public void siteStop() Ji4p6$ .j-  
{ m,.Y:2?*V  
bStop = true; +VIA@`4  
for(int i=0;i<nStartPos.length;i++) 0vY_  
fileSplitterFetch.splitterStop(); c*bvZC^6  
je] DR~  
'&IGdB I  
} #<{v~sVp&  
} MIMC(<  
//负责部分文件的抓取 X/5m}-6d]  
**FileSplitterFetch.java  X\^nV  
*/ [doEArwn  
package NetFox; )Z7Vm2a  
X\^V{v^-  
 wJp<ZL  
import java.io.*; xS*UY.>  
import java.net.*; u]p21)m$x  
-3Kh >b)  
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public class FileSplitterFetch extends Thread { sSM"~_y\  
l;-Ml{}|0  
j G8;p41  
String sURL; //File URL 2Tp2{"sB>A  
long nStartPos; //File Snippet Start Position DiJLWXs  
long nEndPos; //File Snippet End Position gx&es\  
int nThreadID; //Thread's ID y|`-)fY  
boolean bDownOver = false; //Downing is over 1J?v\S$ma`  
boolean bStop = false; //Stop identical 5EYG
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FileAccessI fileAccessI = null; //File Access interface .9
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException dCC*|b8h  
{ & 3#7>
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this.sURL = sURL; I8xdE(o8+  
this.nStartPos = nStart; m2]N%Y  
this.nEndPos = nEnd; dGKo!;7{  
nThreadID = id; v~
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 (W1$+X  
} 1@]&i
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public void run() '$ei3  
{ YxF@1_g  
while(nStartPos < nEndPos && !bStop) sd%j&Su#4  
{ #GzALF97  
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try{ m:@y_:X0  
URL url = new URL(sURL); 8Qvs\TY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'a#lBzu\b  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5`h$^l/  
String sProperty = "bytes="+nStartPos+"-"; p2vN=[g9)  
httpConnection.setRequestProperty("RANGE",sProperty); J%"BCbxW~B  
Utility.log(sProperty); 0|&@)`  
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InputStream input = httpConnection.getInputStream(); F!+1w(b:  
//logResponseHead(httpConnection); n!)$e;l  
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byte[] b = new byte[1024]; ;V,
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int nRead; eL3 _Lz  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) zxR]+9Z
h  
{ j=r1JV @  
nStartPos += fileAccessI.write(b,0,nRead); ;aQ``B  
//if(nThreadID == 1) _ *f>UW*,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); omE- c  
} =AIts[!qd  
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Utility.log("Thread " + nThreadID + " is over!"); 3h7RQ:lUi  
bDownOver = true; ^J
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//nPos = fileAccessI.write (b,0,nRead); ^exU]5nvz  
} us.#|~i<h  
catch(Exception e){e.printStackTrace ();} C4+DZ<pE  
} gN/<g8  
} C;W@OS-;  
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//打印回应的头信息 T$;S  
public void logResponseHead(HttpURLConnection con) ';C'9k<P:  
{ gk6f_0?X'  
for(int i=1;;i++) (/:m*x*6  
{ {JE [  
String header=con.getHeaderFieldKey(i); IkCuw./  
if(header!=null) "Zp&7hI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); z\ZnxZ@  
Utility.log(header+" : "+con.getHeaderField(header)); DY2*B"^  
else /VYT](  
break; "&6vFmr  
} ^/C\:hw  
} }3 xkA  
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public void splitterStop() s~M$Wo8  
{ 8~Cmn%  
bStop = true; u)@:V)z  
} q?!HzZ  
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} BUXE s0]Lv  
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/* q`xc h[H  
**FileAccess.java v>8.TE~2  
*//文件访问(定位，写) {4g';  
package NetFox; sOhn@*X  
import java.io.*; x,gk]
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O#)1zD}  
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public class FileAccessI implements Serializable{ T]th3*  
5wue2/gl  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 78l);/E{v  
RandomAccessFile oSavedFile; yCQvo(V[F  
long nPos; Yq ]sPE92  
1jKpLTSs  
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public FileAccessI() throws IOException Q.N!b7r7  
{ 4R'CLN |t  
this("",0); a>47k{RSzE  
} m.lR]!Y=w  
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public FileAccessI(String sName,long nPos) throws IOException 50
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{ mG~kf]Y  
oSavedFile = new RandomAccessFile(sName,"rw"); "
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this.nPos = nPos; TAG@Ab  
oSavedFile.seek(nPos); URb8[~dR:  
} |dR}S!fmG  
3Q,&D'];[  
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public synchronized int write(byte[] b,int nStart,int nLen) ,C,nN
aW  
{ NK0'\~7&  
int n = -1; 7r;16"  
try{ J4+K
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oSavedFile.write(b,nStart,nLen); ]'5Xjcx  
n = nLen; KElEGW  
} L-9fo-  
catch(IOException e) \ ca<L  
{ l8G1N[  
e.printStackTrace (); vn}m-U XA*  
} {0,b[  
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return n; d5^^h<'  
} ei-\t qY_  
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} |y^=(|eM  
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/* ==Egy:<:Q  
**SiteInfoBean.java '&cH,yc;b  
*/ SCfp5W7~  
package NetFox; 'vNju1sfk  
B@*b 9  
kWW2N0~$  
public class SiteInfoBean { -=
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!q+ #JW  
private String sSiteURL; //Site's URL D('.17  
private String sFilePath; //Saved File's Path 7"!`<5o^  
private String sFileName; //Saved File's Name 7<su8*?  
private int nSplitter; //Count of Splited Downloading File #G#gc`S-,  
=\lw.59  
# Wi?I=,  
public SiteInfoBean() Nvd(?+c  
{//nSplitter的缺省值为5 lJ;Wi  
//default value of nSplitter is 5 >@7$=Y>D  
this("","","",5); '> ib K|  
} y'm!h?8  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) QF/ULW0G!  
{ <|l}@\iRX  
sSiteURL= sURL; 'Q=;I  
sFilePath = sPath; uE.BB#  
sFileName = sName; _M%>Qm  
this.nSplitter = nSpiltter; jfG of*  
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$  
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} ah*{NR)  
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public String getSSiteURL() J
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{ m\qeYI6,Z  
return sSiteURL; Gko"iO#  
} H
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4Kch=jt4#  
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public void setSSiteURL(String value) *k7BE_&*0Z  
{ Qa,
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sSiteURL = value; lWY
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} :^ywc O   
v \i"-KH  
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public String getSFilePath() LWCFCkx%  
{ X7!q/1$J  
return sFilePath; HThZ4Kg+  
} wW\[#Ku  
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$w*L' <  
public void setSFilePath(String value) 4|K\pCw  
{ UF7h{V})  
sFilePath = value; "r46Rfa  
} RiQ]AsTtl  
(6$P/k8  
6C2~0b   
public String getSFileName() ]JkEf?;.  
{ u{DEOhtI4  
return sFileName; estiS  
} ~5+RK16  
YH\9Je%jx  
~yJ2@2I  
public void setSFileName(String value) qt}M&=}8Q  
{ kQmkS^R  
sFileName = value; &Pb:P?I  
} J$51z  
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8</wQ6&
|  
public int getNSplitter() =dPokLXn  
{ \'Ae,q|w  
return nSplitter; *,JE[M  
} @e<(o UE  
k4iiL<|  
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public void setNSplitter(int nCount) AY5iTbL1  
{ 6C&&="uww  
nSplitter = nCount; <kFLwF?PM'  
} [eD0L71[  
} [XY%<P3D  
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/* t}eyfflZ  
**Utility.java %]Z4b;W[Y  
*/ '{AB{)1  
package NetFox; ~uc7R/3ss  
qA GjR!=^  
]P3m=/w  
public class Utility { 12lX-~[["  
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public Utility() Ip'tB4Mq  
{ ]i#p2?BR  
h&i*=&<HP6  
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} cuN]}=D  
tQ{/9bN?P  
//线程睡眠 ;+wB!/k,  
public static void sleep(int nSecond) W#bYz{s.  
{ bqE'9GI  
try{ }>hn  
Thread.sleep(nSecond); nq{/fD(2  
} dO82T3T  
catch(Exception e) LJ[zF~4#  
{ B)Y[~4o  
e.printStackTrace (); MOD&3>NI  
} l?*DGW(t{  
} M<Wi:r:  
9;#RzelSp  
//日志 AI2XNSV@Yl  
public static void log(String sMsg) OPNRBMD  
{ Iuxf`sd  
System.err.println(sMsg); CI{2(.n4  
} w1G(s$;C  
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4Et(3[P71  
public static void log(int sMsg) a|FkU%sjzZ  
{ 5e+j51  
System.err.println(sMsg); |H t5a.  
} z&gmaYwq  
} (S!UnBb&  
`2 <:$]  
itzUq,T  
/* FC1rwXL(  
**TestMethod.java jUm-!SK}q  
*/ A5Hx$.Z  
package NetFox; 6nk}k]Ji  
RU~na/3  
#tR:W?!  
public class TestMethod { 8
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~3:VM_  
D 5r
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public TestMethod() 1(Is 7  
{ ///xx/weblogic60b2_win.exe nNCR5&,q  
try{ zgGysjV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =c@hE'{
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); naaKAZ!S  
SiteFileFetch fileFetch = new SiteFileFetch(bean); mEJ7e#  
fileFetch.start(); ;JkIZ8!  
} h*VDd3[#  
catch(Exception e){e.printStackTrace ();} j~N*TXkC  
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%f'pAc|#  
} f![] :L  
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public static void main(String[] args) i?/Q7D<P  
{ ^^v3iCT  
new TestMethod(); J,Ki2'=  
} 50MM05aC  
} Tm`@5  
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