http断点续传简单实现（java)

/* H!6&'=c{k  
**SiteFileFetch.java wc"~8Ah  
*/ }j2t8B^&:  
package NetFox; D;+Y0B  
import java.io.*; w T_l>u  
import java.net.*; 42-T&7k  
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public class SiteFileFetch extends Thread { [
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SiteInfoBean siteInfoBean = null; //文件信息Bean `022gHYv  
long[] nStartPos; //开始位置 _,UYbD\[J}  
long[] nEndPos; //结束位置 +ek6}f
#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 [)I W9E v  
long nFileLength; //文件长度 FB
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boolean bFirst = true; //是否第一次取文件 cd=H4:<T5  
boolean bStop = false; //停止标志 p?P.BU\CR  
File tmpFile; //文件下载的临时信息 
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DataOutputStream output; //输出到文件的输出流 M\IdQY-c  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） l^}5PHLd  
public SiteFileFetch(SiteInfoBean bean) throws IOException K>XZrt  
{ J#iuF'%Ds  
siteInfoBean = bean; wq1s#ag<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `w@z Fc!"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); p}wysVB  
if(tmpFile.exists ()) X(DP=C}v9  
{ Tkp"mT v?<  
bFirst = false; 4mX]JH`UTe  
read_nPos(); L5 Ai  
} wGIRRM !b  
else hg'eSU$J  
{ 6!*zgA5M'  
nStartPos = new long[bean.getNSplitter()];  z{V#_(  
nEndPos = new long[bean.getNSplitter()]; J\'f5)k  
} bS55/M w  
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} 29|nt1Z  
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public void run() 7M?Sndp$  
{ Ip8:~Fl]  
//获得文件长度 rQpQqBu  
//分割文件 s]D1s%Mx  
//实例FileSplitterFetch k6\&[BQs  
//启动FileSplitterFetch线程 =<ht@-1  
//等待子线程返回 6G_{N.{(  
try{ )M7~RN  
if(bFirst) bp}]'NA  
{ 3u;0,:X&  
nFileLength = getFileSize(); z38Pi  
if(nFileLength == -1) rvb@4-i>iI  
{ |H5$VSw  
System.err.println("File Length is not known!"); oj,;9{-  
} Fa#5a'}I  
else if(nFileLength == -2) $lUz!mjG  
{ vrvi] Y8  
System.err.println("File is not access!"); a5w E{K  
} ,E+\SBQS_  
else dXU6TCjU7  
{ AD6 b  
for(int i=0;i<nStartPos.length;i++) &oFgZ.  
{ !D/W6Ic@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9'ky2 ]w  
} _skE\7&>X  
for(int i=0;i<nEndPos.length-1;i++) -Gm}i8;  
{ f67pvyy -  
nEndPos = nStartPos[i+1]; ~ntDzF  
} 4v#s!W  
nEndPos[nEndPos.length-1] = nFileLength; J*^ i=y  
} pp >F)A0v  
} $?pfst~;O  
ykGA.wo7/P  
dzV2;  
//启动子线程 @%^h|g8>Fu  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "|PX5  
for(int i=0;i<nStartPos.length;i++) ~C?)- ]bF  
{ KHeeB`V>J  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Enp;-wG:-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), OY!WEP$F-C  
nStartPos,nEndPos,i); tC7 4=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;iUO1t)^  
fileSplitterFetch.start(); #X?E#^6?E  
} /d$kz&aIV  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N4WX}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A 0;ng2&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e_1L J  
nEndPos = " + nFileLength); xi)M8\K  
// fileSplitterFetch[nPos.length-1].start(); 1XHE:0!dQ  

?|n@%'  
vOtILL6  
//等待子线程结束 Nfmr5MU_  
//int count = 0; TEC#owz  
//是否结束while循环 un)PW&~E  
boolean breakWhile = false; UGoB7TEfn  
h6;zAM}  
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while(!bStop) J d,9<m$  
{ shVEAT'`  
write_nPos(); 5`::#[  
Utility.sleep(500); }=u#,nDl>$  
breakWhile = true; D28>e  
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*nV"X0&  
for(int i=0;i<nStartPos.length;i++) OM@z5UP  
{ o9OCgP`Y  
if(!fileSplitterFetch.bDownOver) NezE]'}  
{ MK!Aq^Jz  
breakWhile = false; mCQ:<#  
break; ~/2OK!M  
} NpS =_QeNw  
} IPt !gSp  
if(breakWhile) (Hs,Tj  
break; 'GLpSWL+*  
6Z@T /"mU(  
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//count++; hXD/
  
//if(count>4) 6E_YUk?KW  
// siteStop(); =(v'8?--  
} 65rf=*kz:  
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X*hPE=2` p  
System.err.println("文件下载结束！"); s Dsq:z  
} nrbP3sf*  
catch(Exception e){e.printStackTrace ();} d$n<^~Z  
} Z!l]v.S  
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dl3}\o_
 
//获得文件长度 C)%qs]  
public long getFileSize() s&\krW&  
{ Qm*XWo  
int nFileLength = -1; fC$@m_-KD  
try{ ]q&NO(:kbq  
URL url = new URL(siteInfoBean.getSSiteURL()); y QGd<(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5>~D3?IAd  
httpConnection.setRequestProperty("User-Agent","NetFox"); wv Mp~  
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6Q]JY,+  
int responseCode=httpConnection.getResponseCode(); $|AasT5w  
if(responseCode>=400) -_Kw3x  
{ 8wn{W_5a  
processErrorCode(responseCode); XaMsIyhI  
return -2; //-2 represent access is error SUjo%3R  
} (?"z!dgc  
4AKPS&k;  
<@Y`RqV+  
String sHeader; eAG)+b  
vD(:?M  
+ 7wMM#z  
for(int i=1;;i++) p+b$jKWQ  
{ Q2* ~9QkU  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); SEH[6W3  
//Utility.log(in.readLine()); @3$I  
sHeader=httpConnection.getHeaderFieldKey(i); Z=Cw7E  
if(sHeader!=null) *rbgDaQ  
{ j Neb*dPoK  
if(sHeader.equals("Content-Length"))
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{ V)`A,7X  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); P{9wJ<  
break; ,|A6l?iV  
} ?@Q0;LG  
} <T;V9(66  
else $${3I4  
break; dQ~GE}[  
} cvo+{u$s  
} K F_Uu  
catch(IOException e){e.printStackTrace ();} x;`Gn_  
catch(Exception e){e.printStackTrace ();} )+|wrK:*v  
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Utility.log(nFileLength); ]f?r@U'AS|  
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return nFileLength; q,<l3rIn  
} 6rj iZ%  
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.AOc$Nt  
//保存下载信息（文件指针位置） s,f2[6\Y  
private void write_nPos() ,9}JPv4Z  
{ pdER#7Tq  
try{ Fx}v.A5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3 !8#wn  
output.writeInt(nStartPos.length); f0Q! lMv  
for(int i=0;i<nStartPos.length;i++) AZE%fOG<i  
{ )Ute
 
// output.writeLong(nPos); >
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output.writeLong(fileSplitterFetch.nStartPos); ;?@Rq"*  
output.writeLong(fileSplitterFetch.nEndPos); Mpyza%zj  
} !/tV}.*  
output.close(); yUD@oOVC0  
} YgjW%q   
catch(IOException e){e.printStackTrace ();} 7Ok-T10  
catch(Exception e){e.printStackTrace ();} 0TA8#c  
} ky]^N)  
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//读取保存的下载信息（文件指针位置） m1jEky(  
private void read_nPos() 7Hv6>z#m  
{ 2bLc57j{`9  
try{ [%R?^*]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); re/u3\S  
int nCount = input.readInt(); f4*(rX  
nStartPos = new long[nCount]; @(oY.PeS<z  
nEndPos = new long[nCount]; Q:7P /  
for(int i=0;i<nStartPos.length;i++) <*z'sUh+}  
{ A^6z.MdYZ  
nStartPos = input.readLong(); wBg?-ji3<  
nEndPos = input.readLong(); {d'B._#i  
} 88X]Uw(+  
input.close(); =WI3#<vDG  
} D</?|;J#/  
catch(IOException e){e.printStackTrace ();} :Zkjtr.\  
catch(Exception e){e.printStackTrace ();} UJDI[`2  
} @ U"Ib  
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private void processErrorCode(int nErrorCode) k$m'ebrS.~  
{ ME]7e^  
System.err.println("Error Code : " + nErrorCode); ;`c:Law4  
} :|S[i('  
E
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//停止文件下载 w5s&Ws  
public void siteStop() w5)KWeGa  
{ L\"wz scn  
bStop = true; zVtTv-DU  
for(int i=0;i<nStartPos.length;i++) EZ/_uj2&SN  
fileSplitterFetch.splitterStop(); 4clCZ@\K^  
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} 3hBYx@jTO  
} 9}2/ko  
//负责部分文件的抓取 3AR'Zvn  
**FileSplitterFetch.java Gw-{`<CxE  
*/ 35AH|U7b  
package NetFox; tC$+;_=+F  

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import java.io.*; {yT<22Fl  
import java.net.*; s0vcGh
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public class FileSplitterFetch extends Thread {
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String sURL; //File URL v,
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long nStartPos; //File Snippet Start Position Q2]7|C  
long nEndPos; //File Snippet End Position "30=!k  
int nThreadID; //Thread's ID pp*MHM)x|q  
boolean bDownOver = false; //Downing is over ? N]bFW"t|  
boolean bStop = false; //Stop identical u 1}dHMoX~  
FileAccessI fileAccessI = null; //File Access interface X"g,QqDD  
cdH`#X  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +kxk z"fP  
{ H3d|eO4+W  
this.sURL = sURL; K)`R?CZ:s  
this.nStartPos = nStart; x~8R.Sg  
this.nEndPos = nEnd; <?8cVLW}O  
nThreadID = id; V_v+ic^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 wod{C!  
} >.C$2bW<L  
r z@%rOWV  
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public void run() Qd% (]L[N.  
{ jL4"FTcE]3  
while(nStartPos < nEndPos && !bStop) RN1KM  
{
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#\Q)7pgi.  
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try{ p((.(fx  
URL url = new URL(sURL); Cx(HsJ!,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); JPT&!%~  
httpConnection.setRequestProperty("User-Agent","NetFox"); r[kHVT8  
String sProperty = "bytes="+nStartPos+"-"; !{uV-c-
5,  
httpConnection.setRequestProperty("RANGE",sProperty); F3Vvqt*2  
Utility.log(sProperty); 1ATH$x  
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InputStream input = httpConnection.getInputStream(); \B/( H)Cd*  
//logResponseHead(httpConnection); (lYC2i_b#  
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{"|GV~  
byte[] b = new byte[1024]; 5y0LkuRR:  
int nRead; ;tD?a7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) EmP2r*"rb  
{ P:XX8&#  
nStartPos += fileAccessI.write(b,0,nRead); [ CU8%%7  
//if(nThreadID == 1) 1_}k)(n  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c No)LF  
} ,<OS:]  
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Utility.log("Thread " + nThreadID + " is over!"); m]=G73jzO  
bDownOver = true; .:;q8FL/  
//nPos = fileAccessI.write (b,0,nRead); H0.&~!,*  
} \4*i;a.kU  
catch(Exception e){e.printStackTrace ();} ke +\Z>BWN  
} K~5(j{Kb8  
} ,0>_(5  
X)
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;%u)~3B$JK  
//打印回应的头信息 \jkDRR[  
public void logResponseHead(HttpURLConnection con) F 'H
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{ kwt;pxp i  
for(int i=1;;i++) ?0s&Kz4B  
{ "b
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String header=con.getHeaderFieldKey(i); GCcSI;w  
if(header!=null) 
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); E
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Utility.log(header+" : "+con.getHeaderField(header)); Gn10)Uf8X  
else A#79$[>w  
break; N *n?hN  
} aMJ9U)wnK  
} bV@5B#] 2R  
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public void splitterStop() 6XeqK*r*  
{ O}lqY?0*  
bStop = true; a9nXh6  
} 0R,Y[).U  
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} mP)im]H  
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/* hA"z0Fszh  
**FileAccess.java ue}lAW{q  
*//文件访问(定位，写) jin?;v  
package NetFox; e=Kr>~q=  
import java.io.*; )jRaQ~Sm  
q]*:RI?wGT  
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public class FileAccessI implements Serializable{ QlxlT$o}  
FCYZ9L5uF  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 gJZ9XLPC  
RandomAccessFile oSavedFile; l)1ySX&BU  
long nPos; Nx(y_.I{K  
04z2gAo  
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public FileAccessI() throws IOException F8Z6Ss|v3  
{ TUd=qnu  
this("",0); W}oAgUd  
} SRk-3:  
X_I.
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#+P)X_i`  
public FileAccessI(String sName,long nPos) throws IOException ?DJ,YY9P  
{ ( e(<4-&  
oSavedFile = new RandomAccessFile(sName,"rw"); %G~%:uJ5  
this.nPos = nPos; =CO#Q$
 
oSavedFile.seek(nPos); "[]72PC  
} 4T#Z[B[  
TWQ{, B  
>E(
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public synchronized int write(byte[] b,int nStart,int nLen) *W<g%j-a  
{ tZY(r {  
int n = -1; wsfn>w?!V  
try{ q|ZQsFZ  
oSavedFile.write(b,nStart,nLen); Sb
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n = nLen; Ibl==Irk  
} j6$_U@)%
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catch(IOException e) !Lj+&D|z  
{ [k
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e.printStackTrace (); })r[qsv  
} ='
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return n; Rs%6O|u7  
} Wj.
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{  
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} r`/tb
^  
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E%+1^ L  
/* l4Y}<j\;  
**SiteInfoBean.java =zW.~(c{  
*/ PfVjfrI[  
package NetFox; D(<20b,  
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public class SiteInfoBean { Lv ,Ls  
(@?PN+68|  
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private String sSiteURL; //Site's URL $ V"7UA22  
private String sFilePath; //Saved File's Path ojd/%@+u+Y  
private String sFileName; //Saved File's Name R|AGN*.  
private int nSplitter; //Count of Splited Downloading File O ijG@bI8  
*tT}y(M  
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public SiteInfoBean() ve /Q6j{  
{//nSplitter的缺省值为5 ~3z10IG  
//default value of nSplitter is 5 v ~%6!Tr  
this("","","",5); sL tsvH#  
} SNd]c  
R:v`\  
1)M>vdrP  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ye_)~,{,p  
{ %k3a34P@  
sSiteURL= sURL; qN_jsJ  
sFilePath = sPath; a4! AvG  
sFileName = sName; EkqsE$52  
this.nSplitter = nSpiltter; x3my8'h@  
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]7^YPFc+  
} ef!V EtEOv  
BY$%gIB6>  
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public String getSSiteURL() ~Hs a6F&F  
{ ~z!U/QR2  
return sSiteURL; NLC}XL  
} !W8'apG&[  
rf8`|9h"7  
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public void setSSiteURL(String value) .yF7{/  
{ #.%;U' #O  
sSiteURL = value; P
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} MqI!i>
 
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public String getSFilePath() 0BIH.ZV#  
{ Ydu=Jg5u7  
return sFilePath; Qp${/  
} sEL[d2oO  
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@&d/}Mx"t  
public void setSFilePath(String value) Jh[fFg]  
{ yHhBUpIo  
sFilePath = value; C=AX{sn  
} [N925?--S  
6kKIDEX  
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public String getSFileName() 4>>d "<}C  
{ 
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return sFileName; e ?H`p"l  
} w.Ft-RXA W  
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public void setSFileName(String value) z.pP~he  
{ W04-D
 
sFileName = value; bY;ah;<  
} oO>mGl36H  
nYMdYt04sl  
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public int getNSplitter() 3m?3I2k  
{ )}7rM6hv  
return nSplitter; }S
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} !B(6  
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&B7X LO[  
public void setNSplitter(int nCount) uQ{ &x6.1  
{ 2rf-pdOvG  
nSplitter = nCount; D'#Wc#b  
} TgVvp0F;  
} m Fwx},dl  
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"wTA9\  
/* ]Z@-r  
**Utility.java ep Eg6   
*/ W)?B{\  
package NetFox; hO@'WoniW  
X)xQKkL0  
p^A9iieHp=  
public class Utility { 4r5?C;g  
zN {'@B  
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public Utility() < ppg$;  
{ >c?Z.of  
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r+;op_
 
} c Q|nL  
DnP>ed"M!  
//线程睡眠 a&p|>,
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public static void sleep(int nSecond) tD.md_E  
{ |28z4
.  
try{  =h\,-8  
Thread.sleep(nSecond); (5re'Pl  
} &hEtVkK  
catch(Exception e) 7g cr$&+e  
{
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e.printStackTrace (); _1f!9ghT\  
} \SS1-UbL  
} egxh  
sM
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//日志 U`D/~KJ{Y  
public static void log(String sMsg) q<yp6Q3^  
{ 8/x@
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System.err.println(sMsg); >Q#_<IcI  
} lzN\~5a}  
AF>J8V  
fn(KmuNA  
public static void log(int sMsg) kcVEE)zb  
{ 0p:FAvvNI  
System.err.println(sMsg); Ua)ARi %  
} B)O{+avu  
} <V#9a83JP  
ds,NNN<HW  
9sifc<za  
/* "m.jcKt  
**TestMethod.java iVLfAN @  
*/ r'#5ncB  
package NetFox; r1yz ?Y_P  
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public class TestMethod { /\V-1 7-  
(PE x<r1   
8hZ+[E}  
public TestMethod() SZW`|ajH  
{ ///xx/weblogic60b2_win.exe 8<z+hWX=4  
try{ 1~Zmc1]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); a.
#`>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Va"Q1 *"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); fgK1+sW  
fileFetch.start(); 8e:J{EG~  
} 3,=97Si=  
catch(Exception e){e.printStackTrace ();} F~2bCy[Z  
) gbns'Z<  
w5w
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} OOn{Wp  
ov*?[Y7|~  
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public static void main(String[] args) tAO,s ZW  
{ sygxV  
new TestMethod(); d _)5Ks}  
} DJvmwFx  
} ]1hW/!  
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