http断点续传简单实现（java)

/*  E7,\s   
**SiteFileFetch.java wKN9HT  
*/ e# DAa  
package NetFox; n >^?BU  
import java.io.*;
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import java.net.*; 6)8']f  
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:>;#/<3{  
public class SiteFileFetch extends Thread { ~tWBCq 6  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Us<lWEX;k  
long[] nStartPos; //开始位置 pfG:PrZ  
long[] nEndPos; //结束位置 QZY(S*Up  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 H0S7k`.  
long nFileLength; //文件长度 E_z@\z MB  
boolean bFirst = true; //是否第一次取文件 #'[ f^xgJ  
boolean bStop = false; //停止标志 %2{E'^#)p-  
File tmpFile; //文件下载的临时信息 J';tpr  
DataOutputStream output; //输出到文件的输出流 Ny#%7%(  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） w?[)nlNW  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]PFc8qv{  
{ Hi9]M3Ub  
siteInfoBean = bean; ]3v  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); SaNx;xgi  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); a36<S0R  
if(tmpFile.exists ()) `U1"WcN  
{ ;rFa I^  
bFirst = false; 0Ec -/   
read_nPos(); `>V.}K^4  
} 6*e:ey U  
else ecb[m2z  
{ *6h.#$\  
nStartPos = new long[bean.getNSplitter()]; dZm{?\^_  
nEndPos = new long[bean.getNSplitter()]; i|<*EXB"  
} R'{V&H^Z  
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} -*WD.|k  
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public void run() aoBM_#  
{ Nb$)YMbA  
//获得文件长度 wxoBq{r;  
//分割文件 NENbr$,G  
//实例FileSplitterFetch k~?@~xm,R  
//启动FileSplitterFetch线程 fF9vV. }  
//等待子线程返回 )a.U|[:y[+  
try{
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if(bFirst) H1X6f7`  
{ XW1
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nFileLength = getFileSize(); ^Ab|\5^3  
if(nFileLength == -1) ,0~'#x>  
{ hGpaHY>My  
System.err.println("File Length is not known!"); \dP2xou=  
} ]6%
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else if(nFileLength == -2) M]&9Kg3  
{ ]-O:|q>]  
System.err.println("File is not access!"); #bGt%*Re p  
} iQA f  
else p1Els/|  
{ -O ej6sILO  
for(int i=0;i<nStartPos.length;i++) $,R|$0B7  
{ O|8p #  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {6n B83BB  
} Oh|Hy/&6W  
for(int i=0;i<nEndPos.length-1;i++) P'g$F<~V  
{ ua2SW(C@  
nEndPos = nStartPos[i+1]; En[cg  
} nzU@}/A/  
nEndPos[nEndPos.length-1] = nFileLength; /N~.,vf  
} 2r1.,1  
} pN?
  
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{| Tl3  
//启动子线程 ]A'E61t<
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; q),yY]5  
for(int i=0;i<nStartPos.length;i++) Og^b'Kx/  
{ >R :Bkf-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h_H$+!Nzb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wVp  
nStartPos,nEndPos,i); j134iVF%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); p*vEVo  
fileSplitterFetch.start(); F(mm0:lT  
} ?&"-y)FG  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WOquG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); g&&5F>mF  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %g
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nEndPos = " + nFileLength); ,|}Pof=]xk  
// fileSplitterFetch[nPos.length-1].start(); >=$( ,8"  
H:2#/1Oz>  
'`^`NI`  
//等待子线程结束 Bh<)e5lP:  
//int count = 0; tKu'Q;J  
//是否结束while循环 e0qU2  
boolean breakWhile = false; ~:v" TuuK  
r,aV11{  
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while(!bStop) (@[c;+x  
{ ^pIT,|myY7  
write_nPos(); J1KV?aR  
Utility.sleep(500); a}EO7tcg,  
breakWhile = true; |]*]k`o<)  
~{/"fTif  
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for(int i=0;i<nStartPos.length;i++) *\L\Bzm  
{ 09HlL=0q  
if(!fileSplitterFetch.bDownOver) |Q[[WHqj2f  
{ <XDYnWz  
breakWhile = false; 1U^;fqvja  
break; .0}]/%al  
} {d|e@`"T  
} W^v3pH-y#  
if(breakWhile) GAI(=  
break; =^%#F~o:  
86y)+h`  
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//count++; \jH^OXxb  
//if(count>4) g]%sX6T  
// siteStop(); Y- esD'MD  
} .W>LEz
'  
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bh V.uBH  
System.err.println("文件下载结束！"); 41dB4Td5t  
} 1g<jr.  
catch(Exception e){e.printStackTrace ();} Jvac|rN  
} 7.}V
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~?E.U,R  
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//获得文件长度 M5\$+Tu  
public long getFileSize() v{tw;Z#  
{ :k&R]bc9  
int nFileLength = -1; x)GpNkx:  
try{ tr?U/YG  
URL url = new URL(siteInfoBean.getSSiteURL()); 0KT^V R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z8 eB5!$  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8U86-'Pq  
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int responseCode=httpConnection.getResponseCode(); Z/G`8|A  
if(responseCode>=400) w&F.LiX^  
{ I.dS-)Y  
processErrorCode(responseCode); ; ,9:1.L  
return -2; //-2 represent access is error h[*:\P`  
} <b>g^ `}?D  
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String sHeader; yX7P5c.   
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for(int i=1;;i++) ^K3Bn  
{ ka=EOiX.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0Ba*"/U]t~  
//Utility.log(in.readLine()); Ie"eqO!  
sHeader=httpConnection.getHeaderFieldKey(i); +Z7:(o<  
if(sHeader!=null) 15J t @{<r  
{
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if(sHeader.equals("Content-Length")) a'!p^/6?  
{ _<^mi!Y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $Cnv]1%  
break; (Q(=MEar  
} ,II-:&H  
} I
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else |\BxKwS^  
break; {ovW6#  
} /0 2-0mNv  
} Q@(tyW+8U@  
catch(IOException e){e.printStackTrace ();} @V=HY  
catch(Exception e){e.printStackTrace ();} R1?LB"aN  
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Utility.log(nFileLength); B%(-UTQf  
;%^T*?t  
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return nFileLength; 0zc~!r~  
} b wqd`C  
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:{=2ih-}  
//保存下载信息（文件指针位置）
/NB;eV?  
private void write_nPos() $s<bKju  
{ @)x8<  
try{ 7N8a48$8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); FA$1&Fu3Y  
output.writeInt(nStartPos.length); St|B9V?eEB  
for(int i=0;i<nStartPos.length;i++) P$i d?  
{ =z4kK_?F,  
// output.writeLong(nPos); aTFT'(O,  
output.writeLong(fileSplitterFetch.nStartPos); i p; RlO  
output.writeLong(fileSplitterFetch.nEndPos); Dssecc'  
} D:#e;K  
output.close(); 4fL/,j/^  
} @QbTO'UzK`  
catch(IOException e){e.printStackTrace ();} Sp\ 7  
catch(Exception e){e.printStackTrace ();} #xNXCBl]O  
} :\69N/uw`  
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//读取保存的下载信息（文件指针位置） VQ/Jz5^  
private void read_nPos() 8dCa@r&tz  
{ "zx4k8  
try{ [`U9
  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ByivV2qd{  
int nCount = input.readInt(); fl*>m,  
nStartPos = new long[nCount]; A5kz(pj  
nEndPos = new long[nCount]; A[Pz&\@  
for(int i=0;i<nStartPos.length;i++) ^k}%k#)  
{ g3kF&+2i  
nStartPos = input.readLong(); J`[He$7)  
nEndPos = input.readLong(); Y~g*"J5j  
} Wer.VL  
input.close(); 8jjq)d4#  
} -Ou@T#h"  
catch(IOException e){e.printStackTrace ();} c5AEn -Q  
catch(Exception e){e.printStackTrace ();} qV7nF }V{  
} 0k6S`e9gI  
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private void processErrorCode(int nErrorCode) gvy c(d  
{ qIg^R@  
System.err.println("Error Code : " + nErrorCode); eG\`SKx_  
} PNG!q}(c  
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//停止文件下载 !F[^?:pK  
public void siteStop() jLCZ JSK  
{ W>T6Wlxu`6  
bStop = true; p}9bZKyf  
for(int i=0;i<nStartPos.length;i++) 6U[bAp  
fileSplitterFetch.splitterStop(); k/mO(i%qi  
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} 5$Da\?Fpn  
} :vRUb>z  
//负责部分文件的抓取 ;=F]{w]$+  
**FileSplitterFetch.java U]
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*/ `&!J6)OJ  
package NetFox; 1Aw/-FxJ  
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import java.io.*; 9Netnzv%  
import java.net.*; a[A9(Ftn  
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public class FileSplitterFetch extends Thread { <j^bk"l p  
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String sURL; //File URL 5V"g,]'Nd  
long nStartPos; //File Snippet Start Position D0H
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long nEndPos; //File Snippet End Position CF_pIfbaf  
int nThreadID; //Thread's ID G~fM!F0   
boolean bDownOver = false; //Downing is over WC *e#QP  
boolean bStop = false; //Stop identical & U6bOH%P  
FileAccessI fileAccessI = null; //File Access interface +*vg)F:  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ZQ'bB5I  
{ Tye[iJ  
this.sURL = sURL; @EV*QC2l;Y  
this.nStartPos = nStart; dyNKok#  
this.nEndPos = nEnd; FEzjP$  
nThreadID = id; afNqK~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 l1MVC@'pvP  
} /swNhDQ"o  
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public void run() \C eP.,<  
{ =%+O.  
while(nStartPos < nEndPos && !bStop) G.[,P~yy.  
{ AQ` `Dp  
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try{ QFYO_$1Y)  
URL url = new URL(sURL);
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8BgHoQ*  
httpConnection.setRequestProperty("User-Agent","NetFox"); p ! _\a  
String sProperty = "bytes="+nStartPos+"-"; MrGq{,6C  
httpConnection.setRequestProperty("RANGE",sProperty); p3R: 3E6p  
Utility.log(sProperty); %zCV>D  
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InputStream input = httpConnection.getInputStream(); !CO1I-yL  
//logResponseHead(httpConnection); !|@hU/  
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byte[] b = new byte[1024]; #lld*I"d  
int nRead; ~ WO  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <g4
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{ {BS}9jZx  
nStartPos += fileAccessI.write(b,0,nRead); ~aZy52H_#.  
//if(nThreadID == 1)  <RaM@E  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O7of9F~"  
} lNwqWOWy  
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Utility.log("Thread " + nThreadID + " is over!"); 6J""gyK.  
bDownOver = true; "7X[@xX@  
//nPos = fileAccessI.write (b,0,nRead); |DBj<|SX  
} :Ou[LF.O  
catch(Exception e){e.printStackTrace ();} }\$CU N  
} ??u*qO:p  
} dvX
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 'K7m!y  
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//打印回应的头信息 P]mJ01@'  
public void logResponseHead(HttpURLConnection con) m
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{ hq|I%>y  
for(int i=1;;i++) J\%SAit@  
{  Ww&r  
String header=con.getHeaderFieldKey(i); 92 oUQ EK  
if(header!=null) m*f"Y"B.1I  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $c0<I59&|  
Utility.log(header+" : "+con.getHeaderField(header)); p-o8Ctc?V  
else RoLN#  
break; m<liPl uv  
} kIwq%c;  
} w =2; QJ<  
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public void splitterStop() zc.r&(d  
{ Xf%vfAf  
bStop = true; 8c3/n   
} \`oP\|Z  
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} ym;I(TC+  
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/* -2qI2Z  
**FileAccess.java U9Gg#M4tY  
*//文件访问(定位，写) 's\rQ-TV  
package NetFox; @>q4hYF  
import java.io.*; UXPF"}S2
 

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public class FileAccessI implements Serializable{ Fgw$;W  
nU23D@l  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,E&W{b  
RandomAccessFile oSavedFile; l{8t;!2t  
long nPos; =l4F/?u]f@  
X&gXhr#dL\  
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public FileAccessI() throws IOException ?8ady% .ls  
{ +%H2;8{F  
this("",0); Q94p*]W"  
} |]'gd)%S\  
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public FileAccessI(String sName,long nPos) throws IOException q@d6P~[-gj  
{ fiQ/ &]|5  
oSavedFile = new RandomAccessFile(sName,"rw"); ge[&og/$  
this.nPos = nPos; *n`8 -=  
oSavedFile.seek(nPos); fO}Y$y\q  
} 4`p[t;q  
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i|N(=Z=  
public synchronized int write(byte[] b,int nStart,int nLen) lTJM}K  
{ 6Z!OD(/e  
int n = -1; P`y 0FKS  
try{ (P 9$Ei0fv  
oSavedFile.write(b,nStart,nLen); _))--+cL  
n = nLen; bkL5srH  
} @\Yu?_
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catch(IOException e) 7Yly^  
{ lt|UehJF  
e.printStackTrace (); 2^fSC`!  
} r~sQdf  
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p} i5z_tS  
return n; 0[!38  
} UP@-@syGw  
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} J}s)#va9R  
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 `AxhA.&V  
/* B#K2?Et!t  
**SiteInfoBean.java Y?V>%eBu  
*/ &&($LnyA]  
package NetFox; QVQ?a&HYS  
;T?4=15c  
J2Eb"y>/;  
public class SiteInfoBean { M\jTeB"Z  
}~$96|J  
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private String sSiteURL; //Site's URL }|4dEao\  
private String sFilePath; //Saved File's Path VD-2{em  
private String sFileName; //Saved File's Name |k=L&vs  
private int nSplitter; //Count of Splited Downloading File #ZPy&GIr  
i*Ee(m]I  
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public SiteInfoBean() 9|RR;k[  
{//nSplitter的缺省值为5 pTk1iGfB  
//default value of nSplitter is 5 H| 1O>p&  
this("","","",5); m\?H <o0  
} h`,!p  
9?#L/  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =)9@rV&~  
{ "8h7"WR  
sSiteURL= sURL; iLD:}yK  
sFilePath = sPath; yZ]u{LJS  
sFileName = sName; ?\
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this.nSplitter = nSpiltter; c;pv< lX'  
01" b9`jU  
6!^&]4  
} p!xCNZ(m  
BR [3i}Ud  
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public String getSSiteURL() k(.6K[b  
{ wc#E:GJcK  
return sSiteURL; xf]_@T;  
} I@<\DltPi  
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&KS*rHgt?  
public void setSSiteURL(String value) Vy7o}z`  
{ lboi\GP|  
sSiteURL = value; _wKaFf  
} <|MF\D'  
^yo~C3r~  
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public String getSFilePath() lEe<!B$d"  
{ 
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return sFilePath;  jA}b=c  
} IDIok~B=e  
E'O[E=  
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public void setSFilePath(String value) M#7w54~b?M  
{ q/lQEfR  
sFilePath = value; 86AZ)UP2D  
} Z.DO 2=+=  
6,q}1-  
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public String getSFileName() KtO|14R:  
{ WQ1~9#  
return sFileName; L H8iHB  
} @z-%:J/$  
n+XLZf#  
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public void setSFileName(String value) 4Lb!Au|Y  
{ zY=eeG+4s  
sFileName = value; 3\B28m  
} j@HOU~x  
[
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public int getNSplitter() <n-}z[09  
{ ;#Y'SK  
return nSplitter; .*Mp+Q}^  
} :[r/ Y  
Y*Ra!]62  
L]kd.JJvy  
public void setNSplitter(int nCount) DQ*T2*L  
{ =+z+`
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nSplitter = nCount; };Oyv7D+b  
} +>}L
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} rn9n_)  
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/* J_S8=`f%  
**Utility.java @/,:"
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*/ m0Geq.  
package NetFox; =f/CBYNw@V  
VchI0KL?  
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public class Utility { j"F?^0aR,Q  
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public Utility() >'1h  
{ BICG@  
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} U #C@&2  
g2;lEW  
//线程睡眠 "P9(k>  
public static void sleep(int nSecond) DYDeb i6  
{ C<Z{G%Qm  
try{ ?Gl]O3@3  
Thread.sleep(nSecond); bEKhU\@=J  
} %vil~NU  
catch(Exception e) ?XbM  
{ 7tbY>U8  
e.printStackTrace (); hp1+9vEN  
} l+a1`O  
} =(]Z%Q-V  
d%za6=M  
//日志 ;,}Dh/&E  
public static void log(String sMsg) mCyn:+  
{ M$48}q+  
System.err.println(sMsg); Zz1nXUZ  
} `/O AgV"`  
bp!Jjct  
JC MUK<CG  
public static void log(int sMsg) 6_s(Kx>j  
{ ^)(-7H  
System.err.println(sMsg); b'W.l1]<-  
} Fw S>V2R  
} 5a-x$Qb9  
s&hr$`V4  
vc :%  
/* VsJiE0'%  
**TestMethod.java z2>LjM) #  
*/ v\[+  
package NetFox; .g3=L  
aeISb83Y|  
* bd3^mP  
public class TestMethod { P)kJ[Zv>f  
DXo]O}VF  
q)mG6Su d  
public TestMethod() /O5&)%N  
{ ///xx/weblogic60b2_win.exe -p>~z )  
try{ !> =ybRe  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); i
y8Jl  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); W#%s0EN<_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?!K6")SE  
fileFetch.start(); nT
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} X@"G1j >/  
catch(Exception e){e.printStackTrace ();} xorafL  
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} A#6zINK#B  
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BY.k.]/  
public static void main(String[] args) Z4EmRa30 p  
{ Lo~;pvv  
new TestMethod(); K8aqC{  
} G[\TbPh  
} IH;sVT$M  
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