http断点续传简单实现（java)

/* *U
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**SiteFileFetch.java fxcE1=a  
*/ _;PQt" ]  
package NetFox; oT{9P?K8  
import java.io.*; 1!1JT;gG^9  
import java.net.*; (sKg*G2  
7I[[S!((s  
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public class SiteFileFetch extends Thread { g4WmUV#wp  
#!Cg$6%x9  
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SiteInfoBean siteInfoBean = null; //文件信息Bean viG=Ap.Th  
long[] nStartPos; //开始位置 nr]=O`Mvh  
long[] nEndPos; //结束位置 2`]c&k;]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 .vKgiIC:  
long nFileLength; //文件长度 c/K#W$ l  
boolean bFirst = true; //是否第一次取文件 B@-\.m  
boolean bStop = false; //停止标志 k$%{w\?Jf  
File tmpFile; //文件下载的临时信息 !6|_`l>G,  
DataOutputStream output; //输出到文件的输出流 c
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） rwDLBpk  
public SiteFileFetch(SiteInfoBean bean) throws IOException )$^xbC#j`3  
{ 28^/By:J  
siteInfoBean = bean; 2tK~]0x  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .'M.yE~5J  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); @~2k5pa  
if(tmpFile.exists ()) 15{^
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{ ;*qXjv& K  
bFirst = false; 65zwi-  
read_nPos(); "-S!^h/v  
} ^r}Uu~A>  
else ?3N/
#  
{ aN"
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nStartPos = new long[bean.getNSplitter()]; ;fqp!|J  
nEndPos = new long[bean.getNSplitter()]; D?E VzG  
} Eo$l-Hl5=  
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} 3SWDPy  
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public void run() ){GJgk|P  
{ |8}y?kAC  
//获得文件长度 w#9.U7@.  
//分割文件 Qq{t
X  
//实例FileSplitterFetch oa+'.b~  
//启动FileSplitterFetch线程 n\Is}Czl  
//等待子线程返回 X ([^i;mr  
try{ q#Otp\f  
if(bFirst) ';.TQ_I7Y  
{ :D}?H@(69  
nFileLength = getFileSize(); O^c?w8   
if(nFileLength == -1) :Dr4?6hdr  
{ mn1!A`$  
System.err.println("File Length is not known!"); XH0{|#hwN  
} :OU(fz]  
else if(nFileLength == -2) e{2Za   
{ hTAc}'^$  
System.err.println("File is not access!"); 6/QWzw.0c  
} $hJ 4=F  
else i{:?Iw 'ay  
{ ([JFX@  
for(int i=0;i<nStartPos.length;i++) %\v  
{ G|?V}pZ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~>]Ie~E: (  
} :'
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for(int i=0;i<nEndPos.length-1;i++) f3,Xb ]h  
{ [PrJf"Z "  
nEndPos = nStartPos[i+1]; U2_;  
} #I ,c'Vj  
nEndPos[nEndPos.length-1] = nFileLength; %,N-M]Jf  
} <6N3()A)%1  
} bMqS:+  
<1sUK4nQ,  
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//启动子线程 M+=q"#&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ('_S1?y  
for(int i=0;i<nStartPos.length;i++) 6jal5<H  
{ u8~5e  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N:^
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ;%n(ARZ#  
nStartPos,nEndPos,i); iee`Yg!EOH  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w `M/0.)V  
fileSplitterFetch.start(); cJ,`71xop,  
} 9mv6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), HRd02tah  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |[bQJ<v6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 7z&^i-l.  
nEndPos = " + nFileLength); wzI*QXV2s  
// fileSplitterFetch[nPos.length-1].start(); A.P*@}9  
]G~u8HPH!m  
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//等待子线程结束 dfeN_0`-  
//int count = 0; >&qaT*_g  
//是否结束while循环 kdm@1x  
boolean breakWhile = false; i;+<5
_  
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while(!bStop) 7 (i\?  
{ (5^SL Y  
write_nPos(); M<)Vtn  
Utility.sleep(500); H%Sx*|  
breakWhile = true; TP/bPZY  
fVBu?<=d  
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for(int i=0;i<nStartPos.length;i++) 1w?DSHe  
{ %aJ8wYj*  
if(!fileSplitterFetch.bDownOver) O6!:Qd  
{ ViG-tb  
breakWhile = false; t4,(W`  
break; =hKu85  
} I#t#%!InH  
} U| 1&=8l
 
if(breakWhile) I* JSb9r  
break; 7y>{Y$n  
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//count++; o7 X5{  
//if(count>4) IQ}YF]I;  
// siteStop(); =Cr F(wVO"  
} A v%'#1w<"  
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System.err.println("文件下载结束！"); 'ZQR
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} *Ry "`"  
catch(Exception e){e.printStackTrace ();} e;)&Hc:Z  
} IDv|i.q3  
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0--0+?  
//获得文件长度 i/WiSwh:  
public long getFileSize() 79
(Px2H2  
{ BnLE+
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int nFileLength = -1; naKB2y]l  
try{ MDKiwT@#  
URL url = new URL(siteInfoBean.getSSiteURL()); L%O( I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Lv?e[GA  
httpConnection.setRequestProperty("User-Agent","NetFox"); (!`]S>_w9  
[
6t!}q  
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int responseCode=httpConnection.getResponseCode(); %]i("21  
if(responseCode>=400) 0?nm`9v6  
{ Arb-,[kwN  
processErrorCode(responseCode); 5hbQUF ,Q  
return -2; //-2 represent access is error kUG3_ *1 .  
} oVSq#I4  
V|8`]QW@  
#/Qe7:l  
String sHeader; u?n{r  
.)eX(2j\
 
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for(int i=1;;i++) U$(AZ|0  
{  $VCWc#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); k
drya  
//Utility.log(in.readLine()); \!4sd2Yi  
sHeader=httpConnection.getHeaderFieldKey(i); /P/S0  
if(sHeader!=null) MzsDDP+h  
{ qrmJJSJ  
if(sHeader.equals("Content-Length")) ?0
VLx,kp  
{ -]h3s >
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); IuQY~!  
break; Vi~F Q  
} iE$/ Rcp  
} !Z6GID})p  
else OW12m{  
break; ei8OLcw:x  
} [=Yfdh M8S  
} *?`:=  
catch(IOException e){e.printStackTrace ();} _YH)E^If  
catch(Exception e){e.printStackTrace ();} FFNv'\)  
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Utility.log(nFileLength); uz1t uX_  
>_y>["u6J#  
^xGdRaU#  
return nFileLength; In)#`E` g.  
} j/R  
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'~E&^K5hr  
//保存下载信息（文件指针位置） IdlW[h3`[  
private void write_nPos() uL!{xuN  
{ MOFIR wVZ+  
try{ TCSm#?[B  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5s>$  
output.writeInt(nStartPos.length); m#'2 3  
for(int i=0;i<nStartPos.length;i++) g|PVOY+|^  
{ uE>2*u\  
// output.writeLong(nPos); 1_7}B4  
output.writeLong(fileSplitterFetch.nStartPos); $o`N%]  
output.writeLong(fileSplitterFetch.nEndPos); -,~n|ceI  
} =S-'
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output.close(); 1x]U&{do  
} J*8fGR%  
catch(IOException e){e.printStackTrace ();} &Q^M[X  
catch(Exception e){e.printStackTrace ();} DB yRP-TH  
} EM*YN=So  
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oSt-w{!  
//读取保存的下载信息（文件指针位置） gJ>?<F;  
private void read_nPos() c8gdY`  
{ GP uAIoBo  
try{ Rtn.cSd  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); nVoPTr  
int nCount = input.readInt(); lhx6+w  
nStartPos = new long[nCount]; ]OH
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nEndPos = new long[nCount]; z@cL<.0CE  
for(int i=0;i<nStartPos.length;i++) POc< G^  
{ R\+p`n$  
nStartPos = input.readLong(); `ejE)VL=8h  
nEndPos = input.readLong(); !E> *Mn  
} 8@qYzSx[  
input.close(); L '342(  
} o\8yYX  
catch(IOException e){e.printStackTrace ();} g^1M]1.f  
catch(Exception e){e.printStackTrace ();} $CO^dFf  
} dapQ
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private void processErrorCode(int nErrorCode) Q5iuK#/  
{ APuG8 <R,  
System.err.println("Error Code : " + nErrorCode); .8l\;/o|  
} yjpV71!M  
\no[>L]  
;]MHU/  
//停止文件下载 m"~$JA u  
public void siteStop() )=;0  
{ [a
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bStop = true; IR|A
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for(int i=0;i<nStartPos.length;i++) $ W(m  
fileSplitterFetch.splitterStop(); R\MM2_I  
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} d> `9!)  
} yEy} PCJ&  
//负责部分文件的抓取 Ta%{Wa\U9z  
**FileSplitterFetch.java !SD?  
*/ wnP#.[,V  
package NetFox; v$w!hYsQ  
q/?#+d  
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import java.io.*; I)]wi%  
import java.net.*; 9n$GeRO  
8k]'P*9ulz  
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public class FileSplitterFetch extends Thread { 1fm\5/}'`1  
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9PVM06   
String sURL; //File URL <jQ?l%\  
long nStartPos; //File Snippet Start Position +%=Ao6/#  
long nEndPos; //File Snippet End Position VieC+Kk  
int nThreadID; //Thread's ID jtV{Lf3<  
boolean bDownOver = false; //Downing is over /fWVgyW>6  
boolean bStop = false; //Stop identical #q%xJ[  
FileAccessI fileAccessI = null; //File Access interface Ix^xL+Tm  
A{Z=[]r1`E  
/<9VKMR_k  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException MZB0vdx  
{ H ZIJKk(  
this.sURL = sURL; 5v=%pQbY  
this.nStartPos = nStart; vAbMU  
this.nEndPos = nEnd; bg*4Z?[dd  
nThreadID = id; }>=k!l{  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 d%
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} _y#t[|}w  
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public void run() r+217fS>  
{ t(-noy)  
while(nStartPos < nEndPos && !bStop) B t-o:)pa  
{ ~&[Wqn@MZ  
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try{ "D'A7DA  
URL url = new URL(sURL); mEmz
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6&S;Nrg9  
httpConnection.setRequestProperty("User-Agent","NetFox"); iv2did4  
String sProperty = "bytes="+nStartPos+"-"; ".O+";wk  
httpConnection.setRequestProperty("RANGE",sProperty); $*V:;
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Utility.log(sProperty); ='q:Io?T  
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InputStream input = httpConnection.getInputStream(); 4P(Y34j  
//logResponseHead(httpConnection); v}!eJze
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byte[] b = new byte[1024]; !jL|HwlA  
int nRead; d>*?C!xE  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) d&4]?8}=.  
{ +pZ, RW.D  
nStartPos += fileAccessI.write(b,0,nRead); dElOy?v  
//if(nThreadID == 1) Xi^3o  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @cA`del  
} $73 7oV<  
1P:r=Rt/  
>KmOTM<{  
Utility.log("Thread " + nThreadID + " is over!"); 3`S|I_$(T"  
bDownOver = true; zs<W>
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//nPos = fileAccessI.write (b,0,nRead); \ce (/I   
} wWv")dk3i  
catch(Exception e){e.printStackTrace ();} fNNkc[YTZI  
} ]pp
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} &Ed7|k]H  
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w?)v#]<-  
//打印回应的头信息 
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public void logResponseHead(HttpURLConnection con) wYQTG*&h  
{ bmgK6OyVR  
for(int i=1;;i++) rxH*h`Xx@  
{ _-eF &D  
String header=con.getHeaderFieldKey(i); 2A7g}V  
if(header!=null) qP{S!Z(  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7^7Rk  
Utility.log(header+" : "+con.getHeaderField(header)); wNMgY  
else c Q:.V  
break; \]ouQR.t@\  
} M>W-lp^3  
} <3C~<  
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7?a@i;E<  
public void splitterStop() WBD e`  
{ ivg:`$a[  
bStop = true; mL/]an@Y  
} Rj 2N+59rg  
}#}IR5`=E  
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} b*Ny  
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/* R|aA6} /I  
**FileAccess.java {* S8n09v  
*//文件访问(定位，写) 9s\(yC8h  
package NetFox; Gh}k9-L  
import java.io.*; V^fSrW]  
*)0bifw$&  
v Yt-Nx  
public class FileAccessI implements Serializable{ E +\?|q !T  
N!Dc\d=8q]  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 &2IrST{d:V  
RandomAccessFile oSavedFile; @V{s'V   
long nPos;
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public FileAccessI() throws IOException Sh'>
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{ "q@OMf  
this("",0); )9'eckt  
} (2J_Y*N~>  
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public FileAccessI(String sName,long nPos) throws IOException :M" NB+T  
{ iC-WQkQY  
oSavedFile = new RandomAccessFile(sName,"rw"); V_Z~$  
this.nPos = nPos; ,4dES|)sP  
oSavedFile.seek(nPos); U-.?+`  
} VB6EM|bphl  
*p!K9$4  
i! G^=N
  
public synchronized int write(byte[] b,int nStart,int nLen) q~*3Bk~  
{ tln*Baq  
int n = -1; { ?p55o  
try{ jU')8m[  
oSavedFile.write(b,nStart,nLen); =hE5 ?}EP+  
n = nLen; tBEZ4 W>67  
} nLK%5C  
catch(IOException e) {l&6=z  
{ 4^H(p  
e.printStackTrace (); @ yJ/!9?^  
} `>:ozN#)\  
i<<NKv8;  
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return n; 6itp Mck  
} Xh==F:  
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} I}oxwc  
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/* gE8=#%1<  
**SiteInfoBean.java `5}XmSJ?5  
*/ =\s(v-8  
package NetFox; x:8xGG9  
FG8genCH@  
#5HJW[9  
public class SiteInfoBean { @+A`n21,O  
]>h2h?2te  
Ve>*KHDSt  
private String sSiteURL; //Site's URL 42:~oKiQ$"  
private String sFilePath; //Saved File's Path kM>0>fkjE  
private String sFileName; //Saved File's Name ?! dp0<  
private int nSplitter; //Count of Splited Downloading File w
?kdM1T  
6L@g]f|Y@  
'qBg^c  
public SiteInfoBean() 4)Y=)#=  
{//nSplitter的缺省值为5 L+Q"z*W  
//default value of nSplitter is 5 *,1^{mb  
this("","","",5); V
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} l= 5kd.{  
j
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) c0ET]  
{ G`E%uyjG$j  
sSiteURL= sURL; *1iJa  
sFilePath = sPath; "PGEiLY  
sFileName = sName; !]qwRB$5  
this.nSplitter = nSpiltter; K'N`rx.7  
0hcrQ^BB!b  
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} /Kb7#uq  
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public String getSSiteURL() ;<0Q<0G  
{ `/ix[:}m^  
return sSiteURL; W|~Lmdzj  
} Lu}oC
2
  
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 ~d_Z?Z  
public void setSSiteURL(String value) 2Jrr;"r  
{ 69(
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sSiteURL = value; YcE:KRy  
} {c
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nab:y(]$/  
20;M
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public String getSFilePath() rs2~spN;h  
{ Wfkm'BnV  
return sFilePath; G\tTwX4  
} 1eI>Yy>}  
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/78gXHv  
public void setSFilePath(String value) K)$.0S9d  
{ 3JEH sYxs  
sFilePath = value; F>2t=r*9  
} CF>k_\/Bj  
!TP8LQ  
s0v?*GRX  
public String getSFileName() t`+x5*gW  
{ z~+_sTu  
return sFileName; r|cl6s!P  
} 3Gf^IV-  
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public void setSFileName(String value) EnA) Rz  
{ bmhvC9  
sFileName = value; o+
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} Hkg^  
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DSYtj}>  
public int getNSplitter() r vVU5zA4H  
{ Df02#493  
return nSplitter; 8,=Ti7_  
} 1gts=g.  
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u
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public void setNSplitter(int nCount) UP 1Y3  
{ D}px=?  
nSplitter = nCount; >FFZ8=  
} ,W5pe#n  
} :aLShxKA  
[=u8$5/a  
gl:vJD  
/* ^v*ajy.>  
**Utility.java u!oHP  
*/ 6g29!F`y  
package NetFox; kI]i,v#F  
2,/("lV@0  
TgJx%  
public class Utility { a2vUZhkR  
=r3Yt9  
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public Utility() 9~ajEs  
{ r.xGvo{iY  
.hn{m9|U  
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} x
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;"!dq)  
//线程睡眠 i|Lir{vW  
public static void sleep(int nSecond) k<ku5U1|
 
{ s#&jE GBug  
try{ 6S])IA&VJ  
Thread.sleep(nSecond); 7.CzS  
} "'94E,W  
catch(Exception e) }C"EkT!F  
{ y^Oj4Y:  
e.printStackTrace (); ^USj9HTK  
} gEIjG  
} {Mp>+e@xx  
$n(?oyf  
//日志 J;+tQ8,AP  
public static void log(String sMsg) |q^e&M<  
{ bd_U%0)pi1  
System.err.println(sMsg); FfI$3:9  
} RQy|W}d_  
?CAP8_  
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public static void log(int sMsg) =:P9 $  
{ ;Y?7|G97*S  
System.err.println(sMsg); D}HW7Hnu^  
} &?9p\oY[  
} Pw1V1v&>q  
)6PZ.s/F6p  
zc'!a"  
/* K*'(;1AiW  
**TestMethod.java t2BkQ8vr  
*/ *^=`HE89S  
package NetFox; q!7z4Cn  
vs{i2!^  
$bF.6  
public class TestMethod { r|fJ~0z  
x/~V ZO  
ZajQ B  
public TestMethod() Q6_!I42Y`  
{ ///xx/weblogic60b2_win.exe i:&Y{iPQp  
try{ `dMOBYV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); x7L$x=8s  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t.j q]L  
SiteFileFetch fileFetch = new SiteFileFetch(bean); )Y\},O  
fileFetch.start(); l4O}>#  
} $T^O38$  
catch(Exception e){e.printStackTrace ();} Fr,>|  
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-[~{c]/c  
} TA`*]*O(  
b?CmKiM%  
/]>&OSV  
public static void main(String[] args) KB&t31aq  
{ #8R\J[9  
new TestMethod(); n~8-+$6OR  
} )cUc}Avg}  
} 3.Ni%FF`  
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