http断点续传简单实现（java)

/* E%eTjvvxus  
**SiteFileFetch.java sr0.4VU1  
*/
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package NetFox; =!axQ[)A  
import java.io.*; tho
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import java.net.*; ")/TbTVu  
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public class SiteFileFetch extends Thread { +GgJFBl  
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SiteInfoBean siteInfoBean = null; //文件信息Bean U~~Y'R\NU  
long[] nStartPos; //开始位置 )KZ1Z$<  
long[] nEndPos; //结束位置 i6"/GSA  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 yI&{8DCCw  
long nFileLength; //文件长度 [}7j0&  
boolean bFirst = true; //是否第一次取文件 \2?p  
boolean bStop = false; //停止标志 xvZNshkpAX  
File tmpFile; //文件下载的临时信息 qf/1a CQiP  
DataOutputStream output; //输出到文件的输出流 +Zaew679  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \hjGw,d  
public SiteFileFetch(SiteInfoBean bean) throws IOException 16iymiLz&  
{ R&w2y$  
siteInfoBean = bean; c0J=gZiP  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /jR]sC)xs  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); xwjim7#_:  
if(tmpFile.exists ()) 1E(~x;*)  
{ N30w^W&  
bFirst = false; ]r#YU0  
read_nPos(); g$&uD  
} -hM nA)+  
else }E01B_T9z  
{ XA cpLj]  
nStartPos = new long[bean.getNSplitter()]; U=?hT&w\S  
nEndPos = new long[bean.getNSplitter()]; UbBo#(TZ)  
} R&z)  
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} PGT*4r21  
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public void run() br!:g]Vh  
{ OL,3Jh% x  
//获得文件长度 b&LfL$  
//分割文件 G2FP|mf,  
//实例FileSplitterFetch U Ox$Xwp5&  
//启动FileSplitterFetch线程 -Jo8jE~>V  
//等待子线程返回 -IBf;"8f  
try{ 89I[Dg;"u  
if(bFirst) _$<Q$P6y  
{ M`W%nvEDE  
nFileLength = getFileSize(); (S:+#v  
if(nFileLength == -1) (BtavE  
{ 5lp L$  
System.err.println("File Length is not known!"); 3xhv~be  
} ~R`Rj*Q2Y  
else if(nFileLength == -2) ;WQ@dC  
{ "J0,SFu:  
System.err.println("File is not access!"); ; Q-f6)+&  
} A#s`!SNv  
else x\=2D<@az  
{ IAr  
for(int i=0;i<nStartPos.length;i++) HaP0;9q  
{ eqt+EiH   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); SZOcFmC?  
} P!?Je/Tz]  
for(int i=0;i<nEndPos.length-1;i++) RB5fn+FiZ  
{ q!
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nEndPos = nStartPos[i+1]; L  lP  
} Qm|Q0u  
nEndPos[nEndPos.length-1] = nFileLength; 
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}
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} f%LzWXA  
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//启动子线程 H].G%,2'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Onr#p4UT  
for(int i=0;i<nStartPos.length;i++) Da)rzr|}>3  
{ Zk+J=Cwq}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), NO4V{}?a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), xl%!7?G|$>  
nStartPos,nEndPos,i); lYlU8l5>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); stnyJ9  
fileSplitterFetch.start(); lO/<xSjNd  
} By=/DVm)=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?^z!yD\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); oE+s8Q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 2 }QD>  
nEndPos = " + nFileLength); P)fv:a  
// fileSplitterFetch[nPos.length-1].start(); b\zRwp  
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//等待子线程结束 &"dT/5}6  
//int count = 0; mU1lEx$  
//是否结束while循环 Lc>9[!+#  
boolean breakWhile = false; ;!<WL@C~  

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while(!bStop) m178S3  
{ S7-ka{S  
write_nPos(); e^g3J/aU  
Utility.sleep(500); Jtj_R
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breakWhile = true; W_EM k  
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for(int i=0;i<nStartPos.length;i++) Cc:4n1|]>  
{ q #f U*  
if(!fileSplitterFetch.bDownOver) :$&%Pxm  
{ $tyF(RybG  
breakWhile = false; ?iH`-SY  
break; Ti/t\'6  
} i/rdPbq  
} IxT[1$e  
if(breakWhile) ; Xy\7tx  
break; uLYz!E+E  
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//count++; z`-?5-a]I  
//if(count>4) X{rw+!  
// siteStop(); xq:.|{HUk  
} s8| =1{  
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System.err.println("文件下载结束！"); N> RabD  
} MnvFmYgxA  
catch(Exception e){e.printStackTrace ();} ZF :e6em  
} !j8h$+:K  
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//获得文件长度 w]n20&  
public long getFileSize() P&3'N~k-  
{ 96aA2s
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int nFileLength = -1; ~U&,hFSPY  
try{ &
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URL url = new URL(siteInfoBean.getSSiteURL()); yH>`Kbf T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7s_#X|A$  
httpConnection.setRequestProperty("User-Agent","NetFox"); &H!3]  
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int responseCode=httpConnection.getResponseCode(); "}UJ~ j).  
if(responseCode>=400) ~YHy'.  
{ bkkhx,Oi[G  
processErrorCode(responseCode); |w2H5f{fR  
return -2; //-2 represent access is error *>!O2c  
} EWPP&(u3  
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String sHeader; b:.aZ7+4  
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for(int i=1;;i++) I0 a,mO;m  
{ v8"plx=3  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \P]w^  
//Utility.log(in.readLine()); >ir'v5  
sHeader=httpConnection.getHeaderFieldKey(i); M:|Z3p K  
if(sHeader!=null) FR9<$  
{ X l#P@60  
if(sHeader.equals("Content-Length")) TEl:;4  
{ *)k}@tY  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ZSq7>}  
break; `_sc_Y|C!  
} Go3EWM`Cd8  
} Tl=cniy]  
else ghm5g/  
break; y0qrl4S)v  
} brJ_q0@  
} O(;K]8  
catch(IOException e){e.printStackTrace ();} hK9Trrwau  
catch(Exception e){e.printStackTrace ();} N2uxiXpQZ=  
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Utility.log(nFileLength); J&}/Xw)  
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return nFileLength; ~H/|J^ J  
} yiGq?WA7  
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//保存下载信息（文件指针位置） 24"Trg\WK[  
private void write_nPos() O[f*!  
{ Q=
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try{ f7 V36Q8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Zh`lC1l'  
output.writeInt(nStartPos.length); ~\`lbGJ7?  
for(int i=0;i<nStartPos.length;i++) 'M185wDdAl  
{ 7PO3{I  
// output.writeLong(nPos); Rkm1fYf  
output.writeLong(fileSplitterFetch.nStartPos); WS8m^~S@\  
output.writeLong(fileSplitterFetch.nEndPos); <jF]SN  
} cc7*O  
output.close(); yC !`6$  
} wXp A1,i  
catch(IOException e){e.printStackTrace ();} '/U[ ui0{  
catch(Exception e){e.printStackTrace ();} ~n%~ Z|mMF  
} xaSvjc\  
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//读取保存的下载信息（文件指针位置） X=_pQ+j`^  
private void read_nPos() aYr?J Ol  
{ 02:]  
try{ A,i.1U"w8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); e>~g!S}G  
int nCount = input.readInt(); b{<qt}
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nStartPos = new long[nCount]; q}>1Rr|U`  
nEndPos = new long[nCount]; Htn=h~
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for(int i=0;i<nStartPos.length;i++) ,~8:^*0s  
{ GqumH/;  
nStartPos = input.readLong(); i`/_^Fndyu  
nEndPos = input.readLong(); q\ FF)H  
} yjUZ40Dq  
input.close(); Ov"]&e(I[  
} `rsP
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catch(IOException e){e.printStackTrace ();} Mg;%];2Nt  
catch(Exception e){e.printStackTrace ();} 5G=<2;  
} 8A}w}h  
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private void processErrorCode(int nErrorCode) bqp6cg\p  
{ XJy~uks,  
System.err.println("Error Code : " + nErrorCode); CI"7* z_  
} "OF4#a17  
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//停止文件下载 Vy0s%k  
public void siteStop() M*FUtu  
{ GZ0? C2\  
bStop = true; 5ckL=q"+/  
for(int i=0;i<nStartPos.length;i++) p3ox%4  
fileSplitterFetch.splitterStop(); n 1MZHa,  
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} 1oD,E!+^d  
} |niYN7 17  
//负责部分文件的抓取 B*7Y5_N  
**FileSplitterFetch.java GL$!JKWp  
*/ c7Sa|9*dR  
package NetFox; b/'{6zn  
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import java.io.*; V(_OyxeC{2  
import java.net.*; 2^w3xL"   
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public class FileSplitterFetch extends Thread { u~n*P``{  
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String sURL; //File URL XWN ra  
long nStartPos; //File Snippet Start Position <WFA3  
long nEndPos; //File Snippet End Position G n"]<8yl~  
int nThreadID; //Thread's ID ,Oa-AF/p  
boolean bDownOver = false; //Downing is over stuj,8  
boolean bStop = false; //Stop identical /5Aum?~  
FileAccessI fileAccessI = null; //File Access interface eygmhaE  
+\g/KbV7  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException C(zgBk  
{ 6"fYSn>  
this.sURL = sURL; Q^X  
this.nStartPos = nStart; |{W4JFKJ  
this.nEndPos = nEnd; VuA7rIF$66  
nThreadID = id; k7JE{(Ok  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 WLl_;BgN  
} q1ybJii  
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public void run() `G*7y7  
{ zQ3
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while(nStartPos < nEndPos && !bStop) P^V,"B8t  
{ ;6S,|rC]  
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try{ K"u-nroHW  
URL url = new URL(sURL); HT&CbEa4'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <=.0 P/N  
httpConnection.setRequestProperty("User-Agent","NetFox"); Pyh+HD\  
String sProperty = "bytes="+nStartPos+"-"; Z(DCR/U=(>  
httpConnection.setRequestProperty("RANGE",sProperty); d: D`rpcC  
Utility.log(sProperty); oV"d%ks  
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InputStream input = httpConnection.getInputStream(); {gh41G;n  
//logResponseHead(httpConnection); AsFn%8_I  
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byte[] b = new byte[1024]; @>`+eg][?P  
int nRead; <vMna< /d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) PL$*)#S"$  
{ *D`]7I~}  
nStartPos += fileAccessI.write(b,0,nRead); $pW6a %7  
//if(nThreadID == 1) O~ a`T  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j>jZg<}J  
} J{>9ctN  
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Utility.log("Thread " + nThreadID + " is over!"); hOYm =r  
bDownOver = true; ?bFP'.  
//nPos = fileAccessI.write (b,0,nRead); k1tJ$}  
} X&C&DTB  
catch(Exception e){e.printStackTrace ();} ^(z7?T  
} vJZ0G:1  
} 8vQGpIa,
 
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//打印回应的头信息 8VG6~>ux'>  
public void logResponseHead(HttpURLConnection con) ^n8ioL\*i  
{ AI KLJvte  
for(int i=1;;i++) &\<!{Y<'  
{ MJ5Ymt a  
String header=con.getHeaderFieldKey(i); FY;\1bt<<  
if(header!=null) MTBHFjXO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); k3[rO}>s  
Utility.log(header+" : "+con.getHeaderField(header)); )Ve-)rZ  
else #,dNhUV#  
break; ?%RAX CK  
} be&5vl  
} L8OW@)|  
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public void splitterStop() VnlgX\$}  
{ V11(EZJ/j  
bStop = true; NUxOU>f  
} 1.S7MSpTV  
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} D5]AL5=Xt2  
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/* 0|6]ps4Z7  
**FileAccess.java JFAmND;+  
*//文件访问(定位，写) 5\\#kjjx  
package NetFox; mjgwU8'![  
import java.io.*; LV4\zd6  
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public class FileAccessI implements Serializable{ H~Z$pk%  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~nit~;  
RandomAccessFile oSavedFile; `As|MYv  
long nPos; D$X9xtT  
7 s+j)  
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public FileAccessI() throws IOException zzlqj){F  
{ JFOto,6L:  
this("",0); :TU|;(p   
} #+VH]7]  
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public FileAccessI(String sName,long nPos) throws IOException Wp2W:JX:  
{ @|I:A  
oSavedFile = new RandomAccessFile(sName,"rw"); -dRnozs6W  
this.nPos = nPos; "n<rP 3y  
oSavedFile.seek(nPos); 7JC^+rk  
} c}XuzgSY  
\R"}=7  
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public synchronized int write(byte[] b,int nStart,int nLen) k8>(-W"A  
{ }s*H|z  
int n = -1; VSm[80iR0  
try{ 01N]|F:  
oSavedFile.write(b,nStart,nLen); :+ASZE.  
n = nLen; U2Uf69R  
} 7CKpt.Sz6  
catch(IOException e) cZ8lRVaWW  
{ |\HYq`!g%7  
e.printStackTrace (); ~Te9Lq|  
} O &/9wi>!q  
r'TxYM-R  
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return n; ,(1n(FZ  
} !yUn|v>&p  
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} 4Sj;38F .1  
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/* W|~Jl7hs8Q  
**SiteInfoBean.java #
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*/ =O~ J  
package NetFox; sObH#/l`  
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public class SiteInfoBean { Z.Otci>J  
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private String sSiteURL; //Site's URL ]'L#'"@  
private String sFilePath; //Saved File's Path .,-,@ZK  
private String sFileName; //Saved File's Name .2K4<UOAbm  
private int nSplitter; //Count of Splited Downloading File a'NxsByG]s  
\IL;}D{  
B #[URZ9S  
public SiteInfoBean() ~RdD6V  
{//nSplitter的缺省值为5 '7'*+sgi$  
//default value of nSplitter is 5 Mx-? &  
this("","","",5); fG *1A\t]  
} P4\{be>e  
"PFczoRZ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) | c:E)S\  
{ R04%;p:k#  
sSiteURL= sURL; k!&G;6O-  
sFilePath = sPath; |igr3p5Fw  
sFileName = sName; PIZnzZ@Z;  
this.nSplitter = nSpiltter; bCV3h3<  
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MC 8t"SB  
} ( M > C  
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public String getSSiteURL() Z.4 vKO[<  
{ a&sVcsX  
return sSiteURL; "wPA;4VQ  
} miWPLnw=L  
9s#Q[\B!  
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public void setSSiteURL(String value) &Zxo\[lP  
{ |b BA0.yS  
sSiteURL = value; J|O=w(  
} -\6";_Y  
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public String getSFilePath() [N35.O6P6u  
{ 5s
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return sFilePath; 5l(8{,NDt  
} X0
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public void setSFilePath(String value) /~8<;N>,+  
{ %^`b)
  
sFilePath = value; ^~p^N <  
} n+sV$*wvS  
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3Y;<Q>roT  
public String getSFileName() 9_$i.@L1  
{ T%[&[8{8  
return sFileName; YK=o[nPmK  
} bOB<m4  
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public void setSFileName(String value) B4&K2;fg_  
{ xr;:gz!h  
sFileName = value; ""Ub^:ucD  
} hc2AGeZr  
>}uDQwX8  
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public int getNSplitter() D2,2Yy5y  
{ p)x*uqSd  
return nSplitter; H'2J!/V  
} ,qj1"e  
n#US4&uT4A  
3 L:s5  
public void setNSplitter(int nCount) #Epx'$9  
{ Tz`O+fx&  
nSplitter = nCount; k@[P\(a3b  
} *X_-8 ^~  
} -(Zi  
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qe/|u3I<lF  
/* i[+cNJ|$B0  
**Utility.java A89n^@  
*/ ]* #k|>Fl  
package NetFox; Ej[
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public class Utility { T?DX|?2X  
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public Utility() Au=9<WB%H  
{ Q#h*C ZT  
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} z#j)uD  
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//线程睡眠 rUz-\H(-  
public static void sleep(int nSecond) doX8Tq   
{ FX yyY-(O  
try{ 2 &(w\#'  
Thread.sleep(nSecond); 8V08>M  
} }C'H@:/  
catch(Exception e) nt5x[xa  
{ m|CB')  
e.printStackTrace (); u2FD@Xq
?  
} <=yqV]JR  
} &az :YTq  
YF4?3K0F:k  
//日志 #s}cK  
public static void log(String sMsg) {hNvCk  
{ e7$ZA#A_5v  
System.err.println(sMsg); 6m\MYay  
} QAk.~ob  
wnPg).  
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public static void log(int sMsg) ~{xm(p  
{ Dp8`O4YC  
System.err.println(sMsg); O'WBO"  
} y8!#G-
d5  
} lQq&tz,  
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3= q,k<=L  
/* J8
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**TestMethod.java a*D])Lu[  
*/ XMLJX~  
package NetFox; \y^Ho1Fj  
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public class TestMethod { \-h%z%{R  
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ye  
public TestMethod() G9|w o)N  
{ ///xx/weblogic60b2_win.exe .^F(&c*['  
try{ A><q-`bw  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); HT% =o}y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); nF)XZB0F  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *}@zxFe+  
fileFetch.start(); 01_*^iCf5  
} CD"D^\z  
catch(Exception e){e.printStackTrace ();} O,c}T7A'?w  
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&hSABtr}  
} )*CDufRFz  
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public static void main(String[] args) C-:lM1  
{ HO`N]AMw  
new TestMethod(); CC~:z/4,N  
} +%'!+r l  
} en?J#fz  
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