http断点续传简单实现（java)

/* XfEp_.~JM  
**SiteFileFetch.java 8A*tpMV?J
 
*/ i$:yq.DW  
package NetFox; fI.X5c>WK  
import java.io.*; a>ye  
import java.net.*; 6%o@!|=I  
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public class SiteFileFetch extends Thread { d;3f80Kd*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean l r~>!O  
long[] nStartPos; //开始位置 8@6*d.
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long[] nEndPos; //结束位置 u2':~h?l  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 c*(=Glzn  
long nFileLength; //文件长度 V6Of(;r  
boolean bFirst = true; //是否第一次取文件 !0Ak)Q]e'  
boolean bStop = false; //停止标志 a_DK"8I  
File tmpFile; //文件下载的临时信息 `sv]/8RN  
DataOutputStream output; //输出到文件的输出流 ZXbq5p_  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） HR  
public SiteFileFetch(SiteInfoBean bean) throws IOException h9nh9a(2  
{ hA
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siteInfoBean = bean; gxVJH'[V5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0N6 X;M{zh  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); wSALK)T1{  
if(tmpFile.exists ()) _jVJkg)]  
{ ;ae6h [  
bFirst = false; Kr4%D*  
read_nPos(); daf-B-  
} -O@/S9]S)  
else 6hFs{P7  
{ "`pg+t&  
nStartPos = new long[bean.getNSplitter()]; OaByfo<S  
nEndPos = new long[bean.getNSplitter()]; f8f|'v|  
} O`~L*h_  

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} o 7V&HJ[  
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public void run() 0h('@Hb.K#  
{ lZ,$lZg9Z  
//获得文件长度 y7z ,I  
//分割文件 LG?b]'#  
//实例FileSplitterFetch %7Gq#rq  
//启动FileSplitterFetch线程 n*~#]%4  
//等待子线程返回 v=IcVHuf  
try{ '?$<k@mJW  
if(bFirst) I wu^@  
{ 'E\qqE[;  
nFileLength = getFileSize(); u^L_XA  
if(nFileLength == -1) On@p5YRwW  
{ {#+'T13sx  
System.err.println("File Length is not known!"); ,(+ZD@Rg  
} G<~P||Lu^  
else if(nFileLength == -2) I%0J=V;o{  
{ #vR5a}BAk  
System.err.println("File is not access!"); %nkbQ2^  
} 7l'1  
else ?CpM.{{s  
{ NL"w#kTc()  
for(int i=0;i<nStartPos.length;i++) `_{,4oi  
{ ggHl{cl)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6U]"i
 
} J=#9eW  
for(int i=0;i<nEndPos.length-1;i++) ^$8WV&5q>  
{ HDhG1B"NL  
nEndPos = nStartPos[i+1]; EOGz;:b&  
} y8|}bd<Sr  
nEndPos[nEndPos.length-1] = nFileLength; iz`ys.Fu  
} Lo9 \[4FP  
} j2#B l  
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//启动子线程 .R@euIva
 
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 
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for(int i=0;i<nStartPos.length;i++) EmV ZqW  
{ %bhFl,tL  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >>>MTV f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ,0n=*o@W  
nStartPos,nEndPos,i); u z:@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cdfnM%`>\  
fileSplitterFetch.start(); SsIN@  
} mZ#IP  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NV3oJ0f&2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); T(*A0  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", uq]E^#^  
nEndPos = " + nFileLength); \&s$?r  
// fileSplitterFetch[nPos.length-1].start(); @N\ Ht'f  
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0MOn>76$N  
//等待子线程结束 wq#'o9s,  
//int count = 0; vLcOZ^iK  
//是否结束while循环 `6G:<wX  
boolean breakWhile = false; u$1^=  
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while(!bStop) yL3F  
{ oeG?2!Zh  
write_nPos(); p,2H8I){  
Utility.sleep(500); w"h'rw  
breakWhile = true; m^a0JR}u9  
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for(int i=0;i<nStartPos.length;i++) OKNGV,{`  
{ G*^4CJ  
if(!fileSplitterFetch.bDownOver) ~#JX 0J=  
{ |Fzt| \  
breakWhile = false;
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break; V5]\|?=  
} rK cr1VFy  
} au7@-_  
if(breakWhile) bY=Yb  
break; Hd~fSXFl  
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^|%7}=e  
//count++; +PHuQ  
//if(count>4) _dn*H-5hO  
// siteStop(); EaN^<  
} -k@Uo(MB  
ch0x*[N@  
/C[XC7^4'  
System.err.println("文件下载结束！"); N|s8PIcSp  
} (FNX>2Mv  
catch(Exception e){e.printStackTrace ();} N_y#Y{c{(  
} X#u< 3<P  
2H`;?#Uq:  
vb k4  
//获得文件长度 Z4PAdT  
public long getFileSize() g+u5u\k  
{ KU;m.{  
int nFileLength = -1; M0uC0\'#P  
try{ ~RnBs`&!  
URL url = new URL(siteInfoBean.getSSiteURL()); qnU$Pd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vXc
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httpConnection.setRequestProperty("User-Agent","NetFox"); 1?#Wg>7'  
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@-}!o&G0  
int responseCode=httpConnection.getResponseCode(); Z+! 96LR  
if(responseCode>=400) ]"\XTL0  
{ VDPq3`$+v{  
processErrorCode(responseCode); l)91v"vJ  
return -2; //-2 represent access is error )mRKIM}*W  
} A-qpuI;f  
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String sHeader; [$%0[;jtS  
 2dBjc{  
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for(int i=1;;i++) 0Ewt >~n  
{ [r=U-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |#(g8ua7  
//Utility.log(in.readLine()); L~L]MC&  
sHeader=httpConnection.getHeaderFieldKey(i); M%FKg/  
if(sHeader!=null) m}fY5r<<;/  
{ t)*A#
  
if(sHeader.equals("Content-Length")) *Ja,3Qq  
{ 0'tm.,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); n(el  
break; /pnQKy.  
} zH?&FtO  
} \G &q[8F\  
else fm^)u"  
break; 38(|a5  
} :vy./83W  
} W|[k]A` 2  
catch(IOException e){e.printStackTrace ();} G X>T~i\f8  
catch(Exception e){e.printStackTrace ();} T1~,.(#  
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Utility.log(nFileLength); f%TP>)jag!  
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7!E7XP6,~>  
return nFileLength; E 5bo60z  
} Z~Z+Yt;,9a  
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//保存下载信息（文件指针位置） I45\xP4i  
private void write_nPos() ~6:y@4&F  
{ 4\EvJg@Z.  
try{ 1'g{tP"d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); AA0zt N  
output.writeInt(nStartPos.length); &>o?0A6  
for(int i=0;i<nStartPos.length;i++) @V# wYt  
{ lIF*$#`oh*  
// output.writeLong(nPos); "t)|N dZm  
output.writeLong(fileSplitterFetch.nStartPos); ;X2(G  
output.writeLong(fileSplitterFetch.nEndPos);
J*CfG;Y:  
} 5mYI5~ p  
output.close(); wa4(tM2  
} Qz?r4kR  
catch(IOException e){e.printStackTrace ();} 4'-GcH  
catch(Exception e){e.printStackTrace ();} VNLggeX'U  
} s_N]$3'[E  
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//读取保存的下载信息（文件指针位置） 66~]7w  
private void read_nPos() Dhe ]f#d  
{ -,#LTW<.  
try{ BHBMMjY5  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *]_GFixi  
int nCount = input.readInt(); 4FgY!k  
nStartPos = new long[nCount]; E$84c+  
nEndPos = new long[nCount]; /!Kl  
for(int i=0;i<nStartPos.length;i++) 7Y(ySW  
{ L]HYk}oD.  
nStartPos = input.readLong(); ewcgg  
nEndPos = input.readLong(); kaj6C_k|  
} ';bovh@*  
input.close(); ZM%z"hO9R  
} ]tVXao  
catch(IOException e){e.printStackTrace ();} RDu'N  
catch(Exception e){e.printStackTrace ();} m}3POl/*j  
}
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private void processErrorCode(int nErrorCode) |+MV%QG;  
{ Qvd$fY**  
System.err.println("Error Code : " + nErrorCode); ZXj;ymC'  
} Tse Pdkk  
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= A !;`G  
//停止文件下载 t7p`A8
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public void siteStop() _}B:SM  
{ R?Or=W)i  
bStop = true; |O]oX[~  
for(int i=0;i<nStartPos.length;i++) K9y!ZoB  
fileSplitterFetch.splitterStop(); nC5  
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8HLcDS#  
} 7E9h!<5v  
} pMX#!wb  
//负责部分文件的抓取 AQ 5CrYb  
**FileSplitterFetch.java lAwOp  
*/ e[@q{.  
package NetFox; *?+maK{5+  
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import java.io.*; 1!E+(Iq  
import java.net.*; k+S 6)BQ7U  
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public class FileSplitterFetch extends Thread { h?:lO3)TL=  
zAxwM-`  
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String sURL; //File URL ZK[S'(6q  
long nStartPos; //File Snippet Start Position }hFjl4`xa  
long nEndPos; //File Snippet End Position o?J>mpC  
int nThreadID; //Thread's ID ZC1U  
boolean bDownOver = false; //Downing is over z.[ Ok  
boolean bStop = false; //Stop identical m dC.M$  
FileAccessI fileAccessI = null; //File Access interface B94mh  
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uj-q@IKe  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -hP@L ++D  
{ khb Gyg%  
this.sURL = sURL; {O,Cc$_  
this.nStartPos = nStart; ]AGJPuX  
this.nEndPos = nEnd; N+?kFob  
nThreadID = id; N3nk\)V\E  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1b'1vp  
} WQ]~TGW  
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public void run() i%W,Y8\uf*  
{ `C`_2y8  
while(nStartPos < nEndPos && !bStop) h<9h2  
{ h(I~HZ[K&T  
T]nZ3EZ  
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try{ MQQ!@I`  
URL url = new URL(sURL); X!n-nm
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Kk~0jP_B9  
httpConnection.setRequestProperty("User-Agent","NetFox"); U"xI1fg%b  
String sProperty = "bytes="+nStartPos+"-"; f#l/N%VoBZ  
httpConnection.setRequestProperty("RANGE",sProperty); *4^!e/  
Utility.log(sProperty); 6!i0ioZzi0  
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InputStream input = httpConnection.getInputStream(); %rTX
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//logResponseHead(httpConnection); 9`)NFy?  
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byte[] b = new byte[1024]; R9yK"  
int nRead; }tU<RvT  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %t\`20-1<  
{ 'MM#nQ\(  
nStartPos += fileAccessI.write(b,0,nRead); 2D MH@U2  
//if(nThreadID == 1) ~2~KcgPsq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S[NV-)r=  
} }d)>pH  
Z\{WBUR;4t  
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Utility.log("Thread " + nThreadID + " is over!"); CPGXwM=   
bDownOver = true; e@L'H)w,  
//nPos = fileAccessI.write (b,0,nRead); h2KXW}y"4  
} 11 .RG *  
catch(Exception e){e.printStackTrace ();} HqU"iY>b  
} 3;j?i<kM  
} }_M.-Xm  
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//打印回应的头信息 r}QW!^F  
public void logResponseHead(HttpURLConnection con) ;=6++Oq  
{ 8@/]ki`>  
for(int i=1;;i++) v^[Ny0c
M  
{ ,KIa+&vJW@  
String header=con.getHeaderFieldKey(i); 0ldde&!p  
if(header!=null) 8\y%J!b  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `a2Oj@jP  
Utility.log(header+" : "+con.getHeaderField(header)); C>@~W(IE  
else g=[ F W@z  
break; qrNW\ME  
} (^9q7)n  
} ^#S  
}x-~>$:"  
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public void splitterStop() cCU'~  
{ OR( )D~:n  
bStop = true; }<&g1x'pa  
} Qkk~{OuC  
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} #joU}Rj|  
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/* E[htNin.B~  
**FileAccess.java XT= #+  
*//文件访问(定位，写) 4lb3quY$Us  
package NetFox; =o_d2Ak  
import java.io.*; ^=D77 jS  
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public class FileAccessI implements Serializable{ N(}7
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0wZLkU_(  
RandomAccessFile oSavedFile; DZ ~|yH  
long nPos; 5HL JkOV5  
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public FileAccessI() throws IOException Ua V9T:)x  
{ Nf0b?jn-  
this("",0); /n?5J`6  
} m2{z
 
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/ vje='[!  
public FileAccessI(String sName,long nPos) throws IOException \fU{$  
{ x7Ly,  
oSavedFile = new RandomAccessFile(sName,"rw"); zmf5!77  
this.nPos = nPos; A>OL5TCl  
oSavedFile.seek(nPos); xJ>hN@5}i  
} c2?(.UV  
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public synchronized int write(byte[] b,int nStart,int nLen) ^lRXc.c z  
{ x}N+vK  
int n = -1; fPK|Nw]b  
try{ &!/L^Y*+  
oSavedFile.write(b,nStart,nLen); Ax0u \(p<^  
n = nLen; qg:1  
} N_q7ip%z  
catch(IOException e) pR 1v^m|  
{ Wz:MPdz3(  
e.printStackTrace (); k%NY,(:
(  
} -hp,O?PM  
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return n; f>ED  
} yW|yZ(7  
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} bU2)pD!N  
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/* e
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**SiteInfoBean.java m++VW0Y>  
*/ 1xM&"p:  
package NetFox; _=q)lt-UY  
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public class SiteInfoBean { RS<c&{?  
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private String sSiteURL; //Site's URL wzo-V^+q  
private String sFilePath; //Saved File's Path fRaVY`|wK  
private String sFileName; //Saved File's Name b%,5B  
private int nSplitter; //Count of Splited Downloading File A{9Hm:)  
|%&WYm6&#  
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public SiteInfoBean() 1/gY]g
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{//nSplitter的缺省值为5 WF*2^iWJ  
//default value of nSplitter is 5 OYG8%L  
this("","","",5); 7gD$Q
 
} z>~`9Qiw'  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nN@8vivP%  
{  `U(A
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sSiteURL= sURL; CXCU5-  
sFilePath = sPath; Sr2c'T"  
sFileName = sName; }Ax$}#  
this.nSplitter = nSpiltter; s}`=pk/FM  
V%e'H>EC  
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} v[m/>l2[P  
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public String getSSiteURL() S5m1~fz  
{ u"pn'H  
return sSiteURL; YDjQ&EH  
} KMoRMCT  
us`hR!_  
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public void setSSiteURL(String value) t4h05
i  
{ M9bb,`X>Q  
sSiteURL = value; l4R:_Z<  
} 6],5X^*Y  
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public String getSFilePath() uO
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{ \vFkhm  
return sFilePath; {v;Y}o-p  
} A"_;.e`  
;M"hX  
;EFs2-{K  
public void setSFilePath(String value) TrkoLJmB  
{ ?>RJ8\Sj  
sFilePath = value; aWe H,A%  
} =B<g_9d4  
/wCP(1Mw  
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v  
public String getSFileName() C@]Z&H;  
{ 1|z>} xP  
return sFileName; ut-UTW  
} gyI5;il~  
%@H;6   
4^AE;= Q  
public void setSFileName(String value) "=yaeEp  
{ v,+2CVdW  
sFileName = value; ,p$1n;  
} >K50 h  
!^l<jrM  
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public int getNSplitter() z${B|  
{ |!57Z4X  
return nSplitter; !8l4H
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} )2bPu[U  
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public void setNSplitter(int nCount) A`X$jpAn&  
{ h"wXmAf4%  
nSplitter = nCount; P_&
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} ?"qU.}kGL  
} 6wnfAli.  
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/* /JR*X!&"  
**Utility.java pw- C=MY]  
*/ ]d% hU  
package NetFox; s=U_tfpH  
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public class Utility { ajkRL|^  
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v C><N  
public Utility() lv$tp,+  
{ gfih;i.pY  
s\>$ K%!H?  
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} h\D y(\  
5OKbW!  
//线程睡眠 q'c'rN^  
public static void sleep(int nSecond) pmQ9iA@=  
{ (zgXhx_!D  
try{ 9.1%T06$  
Thread.sleep(nSecond); fS!%qr  
} #\t?`\L3  
catch(Exception e) %G\rL.H|  
{ zbi[r  
e.printStackTrace (); Du[$6  
} j>
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} 4V<s"  
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//日志 Qy@chN{eP  
public static void log(String sMsg) ]_F%{8|  
{ wCn W]<+  
System.err.println(sMsg); ~p8-#A)X,)  
} L6 h
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a7OD%yQ  
public static void log(int sMsg) 3}LTEsdM  
{ #Q$9Eq8"[  
System.err.println(sMsg); &#;UKk~)Of  
} |*OS;FD5  
} [",W TZ:  
=wI,H@  
~{U~9v^v(  
/* JsVW:8QO~  
**TestMethod.java PN0:,.4  
*/ A9$q;8= <  
package NetFox; rf]]I#C7  
oD~VK,.  
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public class TestMethod { hofZpM  
9:YiLoz?  
d t0?4 d  
public TestMethod() p~+)!Z#  
{ ///xx/weblogic60b2_win.exe p0'A\@|  
try{ vpOzF>O  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); oACuI|b  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); JBi<TDm/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 
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fileFetch.start(); )Hl;9  
} SvDVxK  
catch(Exception e){e.printStackTrace ();} Tv~<W4  
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} 65s|gfu/  
)}n`MRDB  
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public static void main(String[] args) tC-(GDGy5  
{ _YO`x  
new TestMethod(); @ZD1HA,h"  
} *vUKh^="  
} 0(:"q!h  
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