http断点续传简单实现（java)

/* .l+~)$  
**SiteFileFetch.java @GQ8q]N:<  
*/ {R-82%X  
package NetFox; oD#>8Aws  
import java.io.*; vM
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import java.net.*; vA"niO  
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public class SiteFileFetch extends Thread { /J.\p/%\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ml.;wB|  
long[] nStartPos; //开始位置 D!}K)T1~R  
long[] nEndPos; //结束位置 b"nG-0JR  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 qC1U&b#MVx  
long nFileLength; //文件长度 xN3 [Kp  
boolean bFirst = true; //是否第一次取文件 g[s\~MF@s  
boolean bStop = false; //停止标志 sQ}%7BM
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File tmpFile; //文件下载的临时信息 3`k[!!   
DataOutputStream output; //输出到文件的输出流 8.CKH4h  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） N pXgyD  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5BHOHw D{  
{ ~
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siteInfoBean = bean; iog # ,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >H}jR[H'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1a&/Zlr  
if(tmpFile.exists ()) Y:%m;b$]  
{ %e Sm&`  
bFirst = false; b+IOh|  
read_nPos(); eb!s'@  
} 2"leUur~rO  
else A{z>D`d  
{ PNbcy!\U  
nStartPos = new long[bean.getNSplitter()]; %9T~8L @.  
nEndPos = new long[bean.getNSplitter()]; >'aG/(  
} +_ *eu  
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} eQU-&-wt0  
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public void run() %/l-A pu  
{ J}Qs"+x  
//获得文件长度 }+Rgx@XZ\  
//分割文件 i}PK$sa#c  
//实例FileSplitterFetch nW|'l^&  
//启动FileSplitterFetch线程 W/ g
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//等待子线程返回 K,f* SXM  
try{ 0A#*4ap  
if(bFirst) :7p9t.R<$h  
{ fav5e'[$  
nFileLength = getFileSize(); J| SwQE~  
if(nFileLength == -1) {y,nFxLq  
{ XkPv*%Er8  
System.err.println("File Length is not known!"); ;asm 0H(  
} 6xH;:B)d  
else if(nFileLength == -2) EXA^!/)  
{ 4|[<e-W  
System.err.println("File is not access!"); JY{X,?s  
} }@Xh xZu  
else tNK^z7Dm  
{ .#*D!;f  
for(int i=0;i<nStartPos.length;i++) t]s94 R q  
{ Y!SE;N&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !*&4< _  
} JC=dYP}  
for(int i=0;i<nEndPos.length-1;i++) :qxm !P  
{ j!YNg*H  
nEndPos = nStartPos[i+1]; 9Ei5z6Vk/+  
} N83!C=X'  
nEndPos[nEndPos.length-1] = nFileLength; cZqfz  
} ~gP7s_qr{  
} ?RHn @$g8M  
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//启动子线程 14mf}"z\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; lbRzx4=\y  
for(int i=0;i<nStartPos.length;i++) dUIqDl  
{ _ w/_(k  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >-b&v$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wb b*nL|P  
nStartPos,nEndPos,i); 4Rx~s7l  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nE_Cuc>K\  
fileSplitterFetch.start(); alFNSRY  
} z) :ka"e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z:!IX^q;}n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :$NsR*Cq*9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _6ZzuVv3/  
nEndPos = " + nFileLength); 6D|p Qs  
// fileSplitterFetch[nPos.length-1].start(); CphFv!k'Z  
p!_[qs  
Nb0Ik/:<  
//等待子线程结束 q]CeD
 
//int count = 0; Zae.MO^C!  
//是否结束while循环 S#tY@h@XV  
boolean breakWhile = false; {Ur7#h5  
! D$Ooamq  
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while(!bStop) RND9D\7  
{ 6#U^<`  
write_nPos(); $E\^v^LW  
Utility.sleep(500); h$>wv`
 
breakWhile = true; 'S*k_vuN  
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for(int i=0;i<nStartPos.length;i++) R:M,tL-l  
{ "N 3)Qr  
if(!fileSplitterFetch.bDownOver) "oR@JbdX  
{ wPX*%0]  
breakWhile = false; Br!9x{q*  
break; V^TbP.  
} 6Z?Su(s(5  
} O(c@PJem  
if(breakWhile) 0mTr-`s  
break; 5pfYEofK[  
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//count++; d$G}iJ8$mp  
//if(count>4) ,$N#Us(Wa  
// siteStop(); x6W`hpL  
} GSi>l,y'  
j/KO|iNL2  
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System.err.println("文件下载结束！"); [c~kF+8  
} "g0(I8  
catch(Exception e){e.printStackTrace ();} y t5H oy  
} *z8|P#@  
/TV=$gB`  
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//获得文件长度 6;iJ*2f5V  
public long getFileSize() |ZiC`Nt  
{ ) #+^ sAO  
int nFileLength = -1; H C0w;MG)  
try{ xr%#dVk  
URL url = new URL(siteInfoBean.getSSiteURL()); tU:EN;H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =r9r~SR#  
httpConnection.setRequestProperty("User-Agent","NetFox"); "N5!mpD"  
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int responseCode=httpConnection.getResponseCode(); *F`A S>  
if(responseCode>=400) f-
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{ Iz@)!3h  
processErrorCode(responseCode); 4(8xjL:  
return -2; //-2 represent access is error 'hqBo|  
} +>\id~c(  
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String sHeader; y3G `>  
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for(int i=1;;i++) = ieag7!  
{ 6#@ f'~s  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >znRyQ~bM  
//Utility.log(in.readLine()); ZJ*g))k7  
sHeader=httpConnection.getHeaderFieldKey(i); /JkC+7H4  
if(sHeader!=null) [7FItlF%I  
{ XB59Vm0E=  
if(sHeader.equals("Content-Length")) BV#78,8(  
{ Z\}K{#   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); C3NdE_E  
break; H1n1-!%d  
} \QE)m<G
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} 67SV~L#%O  
else ^vilgg~  
break; -Go 7"j  
} ig}A9j?]  
} A][fLlpr  
catch(IOException e){e.printStackTrace ();} '6y}ZE[  
catch(Exception e){e.printStackTrace ();}  Q6'x\  
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Utility.log(nFileLength); 9}a_:hAy/  
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return nFileLength; @c9^q>Uv  
} +5VLw  
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//保存下载信息（文件指针位置） evkH05+;W  
private void write_nPos() b2b?hA'k  
{ Mj[f~  
try{ Wjhvxk  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Um#Wu]i  
output.writeInt(nStartPos.length); e@:sR  
for(int i=0;i<nStartPos.length;i++) {:@tQdM:i8  
{ ^WBuMCe  
// output.writeLong(nPos); ;qH
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output.writeLong(fileSplitterFetch.nStartPos); M@0;B30L  
output.writeLong(fileSplitterFetch.nEndPos); ?T+q/lt4  
} g~(E>6Y  
output.close(); [
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} \]$IDt(s  
catch(IOException e){e.printStackTrace ();} Y"A/^]   
catch(Exception e){e.printStackTrace ();} (Jz;W<E  
} #9K-7je;j  
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//读取保存的下载信息（文件指针位置） >4t+:Ut:  
private void read_nPos() >jD[X5Y  
{ B&D}F=U  
try{ W`c'=c  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); qucq,Yw  
int nCount = input.readInt(); s%<e
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nStartPos = new long[nCount]; M(/r%-D  
nEndPos = new long[nCount]; "etPT@gF  
for(int i=0;i<nStartPos.length;i++) ?lP':'P  
{ D_vbSF)  
nStartPos = input.readLong(); eq UME  
nEndPos = input.readLong(); "~'b
 
} +SwR+H)?  
input.close(); Z?\>JM >;  
} 5LOo8xN  
catch(IOException e){e.printStackTrace ();} o}ZdTf=  
catch(Exception e){e.printStackTrace ();} TqnTS0fx  
} ~?(N  
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private void processErrorCode(int nErrorCode) %$b:X5$Z  
{ uCcYPvm  
System.err.println("Error Code : " + nErrorCode); #'y#"cmQ.  
} DY`kx2e!  
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//停止文件下载 |j,"Pl}il^  
public void siteStop() "men  
{ `^)jLuyu  
bStop = true; ')$+G152  
for(int i=0;i<nStartPos.length;i++) i*Z"Me  
fileSplitterFetch.splitterStop(); "yS _s  
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} _WRFsDZ'  
} -[wGX}}  
//负责部分文件的抓取 z*!%g[3I  
**FileSplitterFetch.java V{!J-nO  
*/ y2^Y/)   
package NetFox; `9BROZnq  
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import java.io.*; M 
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import java.net.*; j3{D^|0bP  
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public class FileSplitterFetch extends Thread { ?M\{&mlF  
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String sURL; //File URL AT2nVakL  
long nStartPos; //File Snippet Start Position ?j"KV_
 
long nEndPos; //File Snippet End Position 8; 0A g  
int nThreadID; //Thread's ID +lHjC$  
boolean bDownOver = false; //Downing is over H}hiT/+$  
boolean bStop = false; //Stop identical ,g2ij  
FileAccessI fileAccessI = null; //File Access interface )-a'{W/t  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException h4T5+~rw  
{ B><d9d  
this.sURL = sURL; ;V*l.gr'2  
this.nStartPos = nStart; 5kCUaP
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this.nEndPos = nEnd; RO 4Z?tz  
nThreadID = id; X\{
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 2N: ,Q8~  
} W\d{a(*  
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public void run() 0jy2H2  
{ L~lxXTG\  
while(nStartPos < nEndPos && !bStop) Egg=yF>T  
{ RI(DXWM|h  
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try{ ' aq!^!z  
URL url = new URL(sURL); gOSJM1Mr3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Enum/O5  
httpConnection.setRequestProperty("User-Agent","NetFox"); vHry&#Pl+  
String sProperty = "bytes="+nStartPos+"-"; 2$+bJJM  
httpConnection.setRequestProperty("RANGE",sProperty); itBwCIjG  
Utility.log(sProperty); Br1&8L-|%  
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InputStream input = httpConnection.getInputStream(); B-ngn{Yc   
//logResponseHead(httpConnection); ;oW6 NJ  
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byte[] b = new byte[1024]; KL1/^1  
int nRead; We$:&K0  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) BTGvN%  
{ ORe(]I`Z  
nStartPos += fileAccessI.write(b,0,nRead); l?Udn0F  
//if(nThreadID == 1) Ta ?_5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,k )w6)  
} q rJ`1  
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Utility.log("Thread " + nThreadID + " is over!"); xST8|H  
bDownOver = true; #hfXZVD  
//nPos = fileAccessI.write (b,0,nRead); zi|+HM  
} rI= v  
catch(Exception e){e.printStackTrace ();} |=Eo?Q_  
} Cn'(<bl  
} 1C}NQ!.  
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//打印回应的头信息 nzd2zY
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public void logResponseHead(HttpURLConnection con) k;K)xb[w|  
{ ^o^H3m  
for(int i=1;;i++) 2D75:@JL}|  
{ 3h;{!
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String header=con.getHeaderFieldKey(i); )Xk0VDNp$/  
if(header!=null) HG^B#yX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .L9j>iP9 *  
Utility.log(header+" : "+con.getHeaderField(header)); z.7cy@N6  
else *7CV^mDm  
break; M2PAy! J  
} m? eiIrMW  
} /1"(cQ%?  
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public void splitterStop() }YB*]<]  
{ iq8GrdL"  
bStop = true; >p)MawT]  
} $+P>~X)  
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} ,F79xx9ufg  
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/* cc,^6[OH@  
**FileAccess.java =d".|k  
*//文件访问(定位，写) #*QO3y~ZM  
package NetFox; v=0(~<7B  
import java.io.*; iX0i2ek  
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public class FileAccessI implements Serializable{ lpQSu
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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 GC>e26\:  
RandomAccessFile oSavedFile; (zgW%{V@  
long nPos; W=j[V Oq  
\#f<!R4  
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public FileAccessI() throws IOException wLi4G@jJ  
{ J#w J4!  
this("",0); +1uF !G&l  
} dYG,_ji  
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public FileAccessI(String sName,long nPos) throws IOException gYNjzew'  
{ ?j40} B]]d  
oSavedFile = new RandomAccessFile(sName,"rw"); ,I7E[LU
  
this.nPos = nPos; @aAW*D~-J  
oSavedFile.seek(nPos); v>$'iT~l  
} <D:.(AUeO  
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public synchronized int write(byte[] b,int nStart,int nLen) %6t2ohO"  
{ P#RR9>Q  
int n = -1; zfc'=ODX  
try{ ]QpWih00V  
oSavedFile.write(b,nStart,nLen); 8"U. Hnu  
n = nLen; MXw hxk#E  
} vK9E   
catch(IOException e) R$
q; !  
{ )CuZDf@  
e.printStackTrace (); I$<<(VWH  
} C1jHz  
q?4p)@#   
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return n; JBi*P.79^  
} yUZb#%n  
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} 6kNrYom  
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/* eM$
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**SiteInfoBean.java fDT%!  
*/ pimtiQqC  
package NetFox; oXb;w@:  
b6U2GDm\s  
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public class SiteInfoBean { cd(GvX'  
S 5/R_5  
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private String sSiteURL; //Site's URL ]L9s%]o  
private String sFilePath; //Saved File's Path Bwa'`+bC  
private String sFileName; //Saved File's Name \HKxh:F'  
private int nSplitter; //Count of Splited Downloading File i.3=!6z  
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%k;|\%B`  
public SiteInfoBean() E^vJ@O  
{//nSplitter的缺省值为5 <kGU,@6PF  
//default value of nSplitter is 5 L1cI`9  
this("","","",5); =p*]Az  
} N+Y]st+  
\/: {)T~  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }T&iewk  
{ 3BtaH#ZY  
sSiteURL= sURL; syaPpM Q-  
sFilePath = sPath; j@SQ~AS  
sFileName = sName; U)E(`{p]  
this.nSplitter = nSpiltter; KwPOO{4]g  
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} Bj1?x  
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public String getSSiteURL() AaWs}M  
{  %-c*C$  
return sSiteURL; ,N!o  
} 9s6U}a'c  
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public void setSSiteURL(String value) >`A9[`$n  
{ ;<j0f~G`  
sSiteURL = value; BYVY)<v/  
} 8W,Jh8N6  
 |8My42yf  
L.S;J[a;  
public String getSFilePath() -o$QS,  
{ VJickXA  
return sFilePath; ki?S~'a  
} @ycDCB(D}  
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public void setSFilePath(String value) HY&aV2|A1  
{ -jb0o/:  
sFilePath = value; _qw?@478  
} 7"20hAd  
 %oZ6l*  
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public String getSFileName() ]yK7PH-{L  
{ nxWY7hU  
return sFileName; 9~]~#Uj  
} WtG~('g>&  
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;7?kl>5]  
public void setSFileName(String value) @~!wDDS  
{ aMWmLpv4'  
sFileName = value; ow_W%I=6  
} JtEo'As:[  
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public int getNSplitter() [|(N_[E|6  
{ LBM ^9W  
return nSplitter; YwDbPX  
} 8ZM&(Lz7u  
pA9+Cr!0Q  

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public void setNSplitter(int nCount) OBOtuu.  
{ #_6I w`0  
nSplitter = nCount; [N7{WSZ&  
} iV'k}rXC  
} 6-z%633DL  
9 Vkb>yFX'  
:Av#j@#  
/* X-6de>=  
**Utility.java ,l!Ta"  
*/ AgS7J(^&3  
package NetFox; ABQ('#78  
#$18*?tLv|  
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public class Utility { coW:DFX  
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public Utility() w_.F' E  
{ ,K9*%rW)  
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} ~;l@|7wGz  

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//线程睡眠 a1EOJ^}0  
public static void sleep(int nSecond) oI }VV6vO  
{ T|nDTezr  
try{ Xe$I7iKD  
Thread.sleep(nSecond); ',9V|jvK  
} 1eS&&J5  
catch(Exception e) b*a#<K$T_  
{ dP3CG8w5  
e.printStackTrace (); cpL7!>^=  
} [xSF6  
} .+PI}[g  
4{y)TZ  
//日志 8IlunJ  
public static void log(String sMsg) aS{|uE]  
{ RIlwdt  
System.err.println(sMsg); wjH
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} 'GNK
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public static void log(int sMsg) n6wV.?8  
{ CDsSrKhx  
System.err.println(sMsg); ]D?"aX'q>  
} <c2E'U)X  
} `7c~mypx  
a!a-b~#cx  
?9!6%]2D  
/* Si_ _8D  
**TestMethod.java 2^r<{0@n  
*/ h}[-'>{  
package NetFox; i+A3~w5c  
?4+9fE<Q  
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public class TestMethod { &Y!-%{e  
k Z?=AXu  
:*I#n  
public TestMethod() fY{1F   
{ ///xx/weblogic60b2_win.exe 2<i!{;u$qL  
try{ I@T8Iv=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .CL[_;}  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Pr3qo4t.L  
SiteFileFetch fileFetch = new SiteFileFetch(bean); = I:.X ;  
fileFetch.start(); U_M$#i{_  
} DVG(Vw  
catch(Exception e){e.printStackTrace ();} X$HIVxyq2  
1a?!@g)  
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} O8+7g+J=!  
0]'7_vDs|  
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public static void main(String[] args) tRs [ YK  
{ SzAJ2:qhl  
new TestMethod(); v|gw9  
} RmI]1S_=  
} Nkjza:f{  
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