http断点续传简单实现（java)

/* :,0(aB  
**SiteFileFetch.java <3{MS],<<  
*/ !l0]IX` F  
package NetFox; E)$>t}$  
import java.io.*; am]M2+,2Ip  
import java.net.*; 3@I0j/1#k1  
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public class SiteFileFetch extends Thread { Sk|e#{  
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SiteInfoBean siteInfoBean = null; //文件信息Bean :>fT=$i@  
long[] nStartPos; //开始位置 =:s`C,l.4  
long[] nEndPos; //结束位置 US ALoe  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;
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long nFileLength; //文件长度 o4kLgY !Q  
boolean bFirst = true; //是否第一次取文件 &" t~d}Rg  
boolean bStop = false; //停止标志 w.
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File tmpFile; //文件下载的临时信息 L5FOlzn  
DataOutputStream output; //输出到文件的输出流 1 jidBzu<  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） M4C8K{}  
public SiteFileFetch(SiteInfoBean bean) throws IOException @vlP)"
 
{ 5j`xSG  
siteInfoBean = bean; <}RI<96  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); n>ui'}L  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); TF/NA\0c$  
if(tmpFile.exists ()) U*r54
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{ }pMVl  
bFirst = false; VC88r
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read_nPos(); .kBkYK8*t  
} <t"T'\3  
else %1Q:{m  
{ 0A)0Zw  
nStartPos = new long[bean.getNSplitter()]; V8M()7uJ  
nEndPos = new long[bean.getNSplitter()]; Qfm$q~`D^W  
} ^Lgvey%  
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} c#N4XsG,  
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public void run() d&NnpjH}c  
{ ynIC (t  
//获得文件长度 epiviCYC  
//分割文件 B"&-) (  
//实例FileSplitterFetch :8)Jnh\5  
//启动FileSplitterFetch线程 K<J,n!zc  
//等待子线程返回 #BLHHK/[  
try{ AZ3T#f![L@  
if(bFirst) .|O T#"LP  
{ '8;bc@cE  
nFileLength = getFileSize(); xvO
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if(nFileLength == -1) uy hh"[  
{ ;gZ ^c]\  
System.err.println("File Length is not known!"); vkE`T5??  
} xfb .Z(  
else if(nFileLength == -2) G+<XYkz*  
{ 0*XsAz1,9  
System.err.println("File is not access!"); _c>ww<*3  
} B r#{  
else k77IXT_7u  
{ 0/su`  
for(int i=0;i<nStartPos.length;i++) yI: ;+K  
{ '
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); sGu.G  
} xT+_JT65  
for(int i=0;i<nEndPos.length-1;i++) iM<$ n2t  
{ KHAc!4lA  
nEndPos = nStartPos[i+1]; ~!Nj DDk  
} fmuh9Z  
nEndPos[nEndPos.length-1] = nFileLength; Q-oDmjU  
} '.bf88D  
} TTVmm{6  
,&UKsrs_  
a dqS.xs  
//启动子线程 ,->K)Rs;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; So&gDR;b  
for(int i=0;i<nStartPos.length;i++) 9)oi_U.  
{ r%=-maPL[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B"_O!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2GptK"MrD  
nStartPos,nEndPos,i); V;%ug'j  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >Q/;0>V  
fileSplitterFetch.start(); V$ H(a`!  
} 'SFAJ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,'s}g,L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Lu}jk W*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %nZ:)J>kz  
nEndPos = " + nFileLength); 9
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// fileSplitterFetch[nPos.length-1].start(); T<B}Z11R  
4QA~@pBX^{  
!_
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//等待子线程结束 s/7Z.\  
//int count = 0; *tUOTA 3L  
//是否结束while循环 3>h2W  
boolean breakWhile = false; ^bv^&V&IB  
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while(!bStop) &4:R(]|  
{ M(a%Qk?]/  
write_nPos(); 3mHzOs\jU  
Utility.sleep(500); lOt7ij(,L  
breakWhile = true; e-rlk5k%f  
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for(int i=0;i<nStartPos.length;i++) INA3^p'w  
{ =@!t/LR7kg  
if(!fileSplitterFetch.bDownOver) ;stjqTd  
{ I0+6p8,  
breakWhile = false; 1Vu#:6%  
break;  ;2C  
} 5GM-*Ak@  
} ,>-jZtm  
if(breakWhile) !h.hJt  
break; HV~Fe!J_  
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8oJl ]  
//count++; [#Qf#T%5h  
//if(count>4) uN)c!='I  
// siteStop(); o-rX4=T  
} bG]0|  
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System.err.println("文件下载结束！"); I!L J&>  
} ["D!IqI:  
catch(Exception e){e.printStackTrace ();} D&):2F^9.  
} v.|#^A?Qx  
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//获得文件长度 r-y;"h'  
public long getFileSize() _Ay^v#a  
{ qSNCBn '  
int nFileLength = -1; rQ.zqr  
try{ o-=|}u]mz  
URL url = new URL(siteInfoBean.getSSiteURL()); f8;?WSGyD2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }<^mUG  
httpConnection.setRequestProperty("User-Agent","NetFox"); z,aMbgt  
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int responseCode=httpConnection.getResponseCode(); bny5e:= d  
if(responseCode>=400) !Aj}sh{  
{ >Hnm.?-AWl  
processErrorCode(responseCode); V[(fE=cIN~  
return -2; //-2 represent access is error 'W(u.  
} c]{}|2u  
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String sHeader; !Vyf2xS"  
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for(int i=1;;i++) j,.M!q]  
{ i M !`4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #uU(G\^T  
//Utility.log(in.readLine()); IB;yL/T  
sHeader=httpConnection.getHeaderFieldKey(i); DKjiooD  
if(sHeader!=null) .Exvuo`F  
{ g[(@@TiG  
if(sHeader.equals("Content-Length")) .aT@'a{F  
{ K;6#v%  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); qTJ0}F  
break; M#gxiN  
} "%Ok3Rvv  
} ." xP{  
else {d.z/Buu  
break; r0}x:{$M  
} A^,E~Z!x  
} Pdf-2 Tx  
catch(IOException e){e.printStackTrace ();} ~LuGfPO^  
catch(Exception e){e.printStackTrace ();} 6=/sEzS'  
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J
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Utility.log(nFileLength); vqN/crJ@  
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return nFileLength; DT`HS/~fH  
} *V kaFQZ$,  
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q? ">  
//保存下载信息（文件指针位置） bh@CtnO  
private void write_nPos() 9I/l+IS"X  
{ Es+I]o0K  
try{ (?Mn_FNE|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1L*[!QT4  
output.writeInt(nStartPos.length); ]`)5 Qe4  
for(int i=0;i<nStartPos.length;i++) &?R/6"J  
{ V| V9.  
// output.writeLong(nPos); rC!O}(4t%$  
output.writeLong(fileSplitterFetch.nStartPos); VFf;|PHS  
output.writeLong(fileSplitterFetch.nEndPos); Wo "s;Z  
} ^UKAD'_#%O  
output.close(); 1gV?}'jq  
} sm`c9[E  
catch(IOException e){e.printStackTrace ();} F- -g?Q^  
catch(Exception e){e.printStackTrace ();} s;I @En  
} "Ol:ni1  
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//读取保存的下载信息（文件指针位置） 6B8!}6Ojc  
private void read_nPos() (B4)L%  
{ i?!9%U!z4  
try{ rci,&>L"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); av!;k2"
 
int nCount = input.readInt(); Ga5s9wC  
nStartPos = new long[nCount]; cjL)M=pIS  
nEndPos = new long[nCount]; a_c(7bQ  
for(int i=0;i<nStartPos.length;i++) B2kZ_4rB  
{ fx|d"VF[  
nStartPos = input.readLong(); t}k:wzZ@  
nEndPos = input.readLong(); mI7lv;oN<5  
} 6]iU-k0b  
input.close(); W+a/>U  
} ?+.mP]d_  
catch(IOException e){e.printStackTrace ();} #A5X,-4G  
catch(Exception e){e.printStackTrace ();} UE^o}Eyg  
} =Q<VU/  
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Z 0
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private void processErrorCode(int nErrorCode) O4X03fUx  
{ ]B )nN':  
System.err.println("Error Code : " + nErrorCode); c?CD;Pk  
} rx9*/Q0F  
jVnTpa!A  
8vuTF*{yZ  
//停止文件下载 o6A$)m5V  
public void siteStop() HVus\s\&y%  
{ MU$tX  
bStop = true;  `vH|P  
for(int i=0;i<nStartPos.length;i++) T!,5dt8L  
fileSplitterFetch.splitterStop(); Bg),Q8\I  
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} {?:]'c  
} i6HRG\9nU  
//负责部分文件的抓取 ~qqxHymc  
**FileSplitterFetch.java <<LLEdB  
*/ bRu9*4t  
package NetFox; Z5v_- +K  
r\"R?P$y|  
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import java.io.*; = zmxki  
import java.net.*; >fYcr#i0[  
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public class FileSplitterFetch extends Thread { Q`*U U82!  
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String sURL; //File URL }169]!R  
long nStartPos; //File Snippet Start Position UdrgUqq)  
long nEndPos; //File Snippet End Position !(q@sw(  
int nThreadID; //Thread's ID ?'~u)O(n  
boolean bDownOver = false; //Downing is over A@>/PB6n  
boolean bStop = false; //Stop identical :lXY% [!6P  
FileAccessI fileAccessI = null; //File Access interface ~TH4='4W3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException [KBa=3>{  
{ 8;pY-j #  
this.sURL = sURL; DU6j0lz  
this.nStartPos = nStart; LN+x!#:e  
this.nEndPos = nEnd; bJn&Y  
nThreadID = id; I8!>7`L  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 u)Kiw
a  
} D4c'6WGb@  
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1av#u:jy~>  
public void run() JL4E`  
{ C:No ^nH>  
while(nStartPos < nEndPos && !bStop) =-Hhm($n  
{ .I~:j`K6  
R=.?el  
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try{ 9^DAlY,x.  
URL url = new URL(sURL); w>*Jgc@A*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); YT?Lt!cl=  
httpConnection.setRequestProperty("User-Agent","NetFox"); WD\Yx~o  
String sProperty = "bytes="+nStartPos+"-"; m4~
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httpConnection.setRequestProperty("RANGE",sProperty); '1DY5`i{  
Utility.log(sProperty); Mlc_w19C9  
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InputStream input = httpConnection.getInputStream(); _LZ(HTX~  
//logResponseHead(httpConnection); gd * b0(  
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byte[] b = new byte[1024]; 47(_5PFb#  
int nRead; Ba
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ! $mY.uu  
{ m7i_Iv  
nStartPos += fileAccessI.write(b,0,nRead); wtSU43D  
//if(nThreadID == 1) (<_kq;XtN0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^f>c_[fR  
} )U|V|yem'  
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Utility.log("Thread " + nThreadID + " is over!"); 9nVb$pfe#  
bDownOver = true; /[lEZ['^  
//nPos = fileAccessI.write (b,0,nRead); 1
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} .aO6Y+Y  
catch(Exception e){e.printStackTrace ();} yKUxjb^b\  
} 4G:~|N.{p  
} R"XycXn_$  
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//打印回应的头信息 m7NW
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public void logResponseHead(HttpURLConnection con) c`x4."m  
{ d#+Nef5  
for(int i=1;;i++) \(7A7~  
{ BegO\0%+  
String header=con.getHeaderFieldKey(i); MR,I`9Pe  
if(header!=null) L/Kb\\f  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cvy 5|;-u  
Utility.log(header+" : "+con.getHeaderField(header)); LhKbZoPp  
else q !9;JrX  
break; 00D.Jn  
} ;bG?R0a  
} jMBMqQNU  
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public void splitterStop() ;{0alhMZ  
{ 5cf?u3r!qJ  
bStop = true; OcMB)1uh\  
} >"1EN5W  
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} G*EF_N.G0  
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/* kF'9@*?J  
**FileAccess.java qbSI98rw  
*//文件访问(定位，写) g$C]ln>"9m  
package NetFox; +dLUq2  
import java.io.*; ShVR{gIs  
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public class FileAccessI implements Serializable{ &a'mG=(K_c  
!BW!!/U  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 b=BNbmX  
RandomAccessFile oSavedFile; 8J&9}@y  
long nPos; z[ ;n2o|s  
+C;;4s)  
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public FileAccessI() throws IOException hd9~Zw]V  
{ 7
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this("",0); ^L.I9a#]  
} 2HVqJib4Yn  
03)irq%l;  
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public FileAccessI(String sName,long nPos) throws IOException Zs}h>$E5_B  
{ PW%ith1)<  
oSavedFile = new RandomAccessFile(sName,"rw"); -*[)CR-{  
this.nPos = nPos; :RIqA/  
oSavedFile.seek(nPos); d~_5Jx  
} 
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public synchronized int write(byte[] b,int nStart,int nLen) i
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{ c{to9Lk.#  
int n = -1; Cp!9 "J:  
try{ :(OV{ u  
oSavedFile.write(b,nStart,nLen); WwoT~O8R  
n = nLen; *;Q#UH  
} H@zZ[  
catch(IOException e)
% 
+  
{ ueU"v'h\  
e.printStackTrace (); f%_$RdU  
} Z%ZOAu&p  
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um]N]cCD`  
return n; nTsV>lQY,  
} WxD$k3U  
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} [-#1;!k  
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/* IeChz d  
**SiteInfoBean.java ,1|=_M31  
*/ i)cG  
package NetFox; n&]J-^Tx  
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B (h`~pb  
public class SiteInfoBean { hC{2LLu;n  
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private String sSiteURL; //Site's URL l0yflF
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private String sFilePath; //Saved File's Path y#Nrq9r:  
private String sFileName; //Saved File's Name S]T71W<i  
private int nSplitter; //Count of Splited Downloading File p}GTOJT}  
JSh'iYJ.  
*S<I!7Q  
public SiteInfoBean() >~_>.R+{  
{//nSplitter的缺省值为5 /;Cx|\  
//default value of nSplitter is 5 N{RHbSa(  
this("","","",5); nWYfe-zQxg  
} FB+nN5D/  
nf_(_O=  
v(sS$2J|}  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Cu$`-b^y  
{ jMR9E@>~E  
sSiteURL= sURL; ]+^4Yq>2  
sFilePath = sPath; [KO\!u|?YS  
sFileName = sName; |%X_<Cpk  
this.nSplitter = nSpiltter; ss|n7  
)"P.n-aF  
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}  wN0?~  
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public String getSSiteURL() 9p02K@wkD  
{ A1zV5-E/  
return sSiteURL; -xH3}K%  
} JP]4* 
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public void setSSiteURL(String value) r 3T#Nv  
{ M tDJ1I%  
sSiteURL = value; J{EK}'  
} iu+H+_  
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public String getSFilePath() kmfz.:j{  
{ =>TXo@rVN  
return sFilePath; sh<JB`^$(?  
} 8p~[8}  
tnmz5Q  
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public void setSFilePath(String value) y(K:,CI  
{ b$Bq#vdg:  
sFilePath = value; <C*%N;F5R  
} }2?-kj7  
Si#XF[/  
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public String getSFileName() 99q$>nx,w  
{ ,n5 [Y)  
return sFileName; Zr\G=0`  
} 1-4*Y
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Me,AE^pgL'  
public void setSFileName(String value) x4_FG{AIu  
{ 7 Uu  
sFileName = value; 9JC8OSjJ  
} !.{{QwZ  
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8 >  
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public int getNSplitter() |-AR)Smt  
{ c*>SZ'T\  
return nSplitter; +qF,XJ2  
} 9VTE?,  
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public void setNSplitter(int nCount) @)@hzXQ  
{ !.={p8X-x  
nSplitter = nCount; CH h6Mnw  
} vr>Rd{dm  
} dNs<`2
m  
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/* j\@|oW0  
**Utility.java hRN>]e,!  
*/ ;V~~lcD&Y`  
package NetFox; iuq%Q\0@w  
b{JxTT}03  
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public class Utility { laFF/g;sRC  

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J 9k~cz  
public Utility() ! XNTk]!  
{ 9o5_QnGE  
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} $3n@2 N`  
(kI@U![u  
//线程睡眠 kIUb`b>B  
public static void sleep(int nSecond) .hXdXY  
{ d5B96;3  
try{ _9zydtw  
Thread.sleep(nSecond); u%Yr&u  
} qg@Wzs7c~  
catch(Exception e) TBqJ.a  
{ s*pgR=dZZ  
e.printStackTrace (); "Q@ZS2;A  
} !tD,phca~  
} {YgB?kt5  
}h)[>I(  
//日志 bQM_rqjJGw  
public static void log(String sMsg) |[lM2  
{ ddD $
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System.err.println(sMsg); Z)zmT%t  
} [HhdeLOX  
U~8 oE_+  
7[ra#>e8'  
public static void log(int sMsg) X[c8P7  
{ mI~k@!3  
System.err.println(sMsg); H0B"?81  
} o93A:fc  
} _7zER6#}  
d6k`=Hlg  
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/* d<v>C-nk%  
**TestMethod.java =#<TE~n2(  
*/ k/#& ]8(  
package NetFox; [0e}%!%M  
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public class TestMethod { P1 `-OM  
Gv}h/zu-  
9m fYB  
public TestMethod() e$^O_e  
{ ///xx/weblogic60b2_win.exe Ci ? +Sl  
try{ ^CwzAB  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); o5FBqt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^25[%aJI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?qQRA|n*  
fileFetch.start(); Y<S,Xr;J:  
} @kLpK  
catch(Exception e){e.printStackTrace ();} ?9801Da#/  
`jb?6;15  
|EaEdA@T  
} =e,2/Ep{i  
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 :RW0<  
public static void main(String[] args) `?VB)  
{ oY{r83h{  
new TestMethod(); h&vq}  
} |f~p3KCfV  
} 'I_\ELb_  
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