http断点续传简单实现（java)

/* g s%[Cv  
**SiteFileFetch.java %8KbVjn  
*/ hC!8-uBK5<  
package NetFox; m4c2WY6k  
import java.io.*; vf!lhV-UG+  
import java.net.*; YQ-V^e6  
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public class SiteFileFetch extends Thread { &7w*=f8I  
,u5iiR  
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SiteInfoBean siteInfoBean = null; //文件信息Bean tRR<4}4R  
long[] nStartPos; //开始位置 _]kw|[)  
long[] nEndPos; //结束位置 iT~ gt/K  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 T mH5+  
long nFileLength; //文件长度 zrA=?[  
boolean bFirst = true; //是否第一次取文件 P9gAt4i  
boolean bStop = false; //停止标志 d`xDv$QZ  
File tmpFile; //文件下载的临时信息 *kNXju  
DataOutputStream output; //输出到文件的输出流 y#J8Yv8  
?[8s`caK.  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?2S<D5MSb  
public SiteFileFetch(SiteInfoBean bean) throws IOException Cyp%E5b7  
{ 'Y5l3xQk  
siteInfoBean = bean; %PM8;]  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); WQNFHRfO*n  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {%v{iE>  
if(tmpFile.exists ()) Mgux(5`;  
{ z|m-nIM  
bFirst = false; %hA0  
read_nPos(); rW
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} ]2mfby  
else dJ7!je1N*  
{ ^Zq3K  
nStartPos = new long[bean.getNSplitter()]; LHusy;<E[  
nEndPos = new long[bean.getNSplitter()]; U1pwk[  
} pE]s>Ta  
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} j>O!|V  
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public void run()  rUBc5@|  
{ (p?B=  
//获得文件长度 >'{'v[qR[G  
//分割文件 b59
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//实例FileSplitterFetch 4^K<RSYs  
//启动FileSplitterFetch线程 jY$3   
//等待子线程返回 _vOSOnU  
try{ Vdb X4^V  
if(bFirst)  B"Ttr+  
{ m$^v/pLkM  
nFileLength = getFileSize(); ,z
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if(nFileLength == -1) ,Y27uey{wa  
{ cG4$)q;q  
System.err.println("File Length is not known!"); fsV_>5I6  
} *|.-y->  
else if(nFileLength == -2) a(K^/BT  
{ ]= 9^wS  
System.err.println("File is not access!"); j.g9O]pi  
} 71k>_'fl  
else zy@ nBi^  
{ dJ=z'?|%g  
for(int i=0;i<nStartPos.length;i++) tQ(gB_
 
{ 2~!+EH  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &&|c-mD+*  
} QR[i9'`<  
for(int i=0;i<nEndPos.length-1;i++) V?-OI>  
{ -hP>;~*4  
nEndPos = nStartPos[i+1]; ;c0z6E /  
} w7Vl,pN,  
nEndPos[nEndPos.length-1] = nFileLength; e~Z>C>J  
} cy( WD
#^  
} Y~-P9  
ck#MpQ!An  
),4cb  
//启动子线程 %gV~e@|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Kd').w  
for(int i=0;i<nStartPos.length;i++) 52z{   
{ 7\Wq:<JL  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )\l(h%s[I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -i"?2gK  
nStartPos,nEndPos,i); f _*F
&-L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kPFqsq  
fileSplitterFetch.start(); ,I8[tiR"b  
} bLyaJ%pa\/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Wt9'-"c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); gwv s  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Y #6G&)M  
nEndPos = " + nFileLength); vC%8-;8{H  
// fileSplitterFetch[nPos.length-1].start(); O",*N  
"1>48Z-UC  
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//等待子线程结束 FKk.BA957h  
//int count = 0; nY50dFA,  
//是否结束while循环 "/$2oYNy+  
boolean breakWhile = false; l5CFm8%  
x10u?@  
"DU1k6XC  
while(!bStop) okQ<_1e{  
{ J=AF`[  
write_nPos(); ?bH!|aW(H  
Utility.sleep(500); ^mCKRWOP'  
breakWhile = true; \LQ54^eB  
Q*8=^[x
 
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for(int i=0;i<nStartPos.length;i++) MXGz_Db4'  
{ &WoS(^  
if(!fileSplitterFetch.bDownOver) o@A|Lm.
 
{ #m36p+U  
breakWhile = false; h][$1b&B  
break; <~R{U>zO  
} 0iTh |K0  
} qfl#ki`,  
if(breakWhile) `w#p8vR  
break; 31k2X81;a  
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y  
y8CH=U[  
//count++; [X\~J &kD  
//if(count>4) O#B2XoZa+  
// siteStop(); OCN@P+L3q  
} wJu,N(U  
vC>8:3Zaq  
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System.err.println("文件下载结束！"); aXRf6:\%  
} $I:&5o i  
catch(Exception e){e.printStackTrace ();} Y>Tok|PV  
} "=3bL>\<  
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43  
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//获得文件长度 "6 \
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public long getFileSize() z"j]m_mH  
{ F<LRo}j"9Q  
int nFileLength = -1; *^Xtorqo  
try{ xmBGZ4f%  
URL url = new URL(siteInfoBean.getSSiteURL()); B4 +A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U)iq  
httpConnection.setRequestProperty("User-Agent","NetFox"); s\3OqJo%)  
fsz:A"0H  
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int responseCode=httpConnection.getResponseCode(); .p$tb2%r  
if(responseCode>=400) {bD:OF  
{ p^THoF'~T  
processErrorCode(responseCode); ,)%$Zxng  
return -2; //-2 represent access is error vG'I|OWg  
} 5><KTya?=  
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String sHeader; d}--}&r  
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for(int i=1;;i++) [ F7ru4"{  
{ Dwuao`~Xm  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); o* C_9M  
//Utility.log(in.readLine()); .LA?2N  
sHeader=httpConnection.getHeaderFieldKey(i); l#cG#-  
if(sHeader!=null) {?hpW+1,#  
{ Ic')L*i7O  
if(sHeader.equals("Content-Length")) 9L9qLF5 t  
{ g8L{xwx<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1%`Nu ]D  
break; G%5ZG$as  
} lXOT>$qR<  
} w$4*/D
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else {dXmSuO  
break; }(/\vTn*1  
} g=L80$1  
} (,OF<<OH  
catch(IOException e){e.printStackTrace ();} ^g N/5
 
catch(Exception e){e.printStackTrace ();} \k>1q/T0V  
;\(X;kQi  
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Utility.log(nFileLength); bd)'1;p  
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return nFileLength; <tto8Y j  
} N97
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//保存下载信息（文件指针位置） Nn='9s9F?}  
private void write_nPos() S?<hs,  
{ fOJTy0jX8  
try{ #b
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output = new DataOutputStream(new FileOutputStream(tmpFile)); #$ooV1E  
output.writeInt(nStartPos.length); gnN"6r1  
for(int i=0;i<nStartPos.length;i++) rBUWzpE"  
{ z=yE- I{  
// output.writeLong(nPos); i)th] 1K%  
output.writeLong(fileSplitterFetch.nStartPos); am+w<NJ(us  
output.writeLong(fileSplitterFetch.nEndPos); P^[y~I#{  
} _bn "c@s  
output.close(); 9
>9,  
} yV
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catch(IOException e){e.printStackTrace ();} 2uLBk<m5c  
catch(Exception e){e.printStackTrace ();} O b'Br
  
} w9TE E,t;5  
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//读取保存的下载信息（文件指针位置） %WlTx&jSgE  
private void read_nPos() +=K =B  
{ \-8S"  
try{ _o7t| pl~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); zEk/15  
int nCount = input.readInt(); ,{X}C  
nStartPos = new long[nCount]; qT~a`ou:  
nEndPos = new long[nCount]; \wF-[']N  
for(int i=0;i<nStartPos.length;i++) W5,&*mo  
{ t W}"PKv  
nStartPos = input.readLong(); MFQyB+Z  
nEndPos = input.readLong(); IxaF*4JG  
} u~7fK  
input.close(); E<sd\~~A:  
} JA~q}C7A7o  
catch(IOException e){e.printStackTrace ();} Lu CiO  
catch(Exception e){e.printStackTrace ();} N;gY5;0m  
} $i@I|y/  
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private void processErrorCode(int nErrorCode) *Gul|Lp$<I  
{ ]-;M
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System.err.println("Error Code : " + nErrorCode); spT$}F2n  
} 
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//停止文件下载 M $f6.j  
public void siteStop() h43py8v  
{ L7]o^p{g}Q  
bStop = true; '0w</g  
for(int i=0;i<nStartPos.length;i++) i>O8q%BnJ  
fileSplitterFetch.splitterStop(); Xo$SQ0K  
mDx=n.lIz  
]=ADX}  
} RT|1M"?$  
} .$fSWlM;  
//负责部分文件的抓取 " v<O)1QT  
**FileSplitterFetch.java 9oYE  
*/ 0Wj,=9q  
package NetFox; ]>
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8([ MR  
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import java.io.*; C8x9 Jrc  
import java.net.*; -Fq`#"  
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public class FileSplitterFetch extends Thread { yLPP6_59$  
l <p(zLR  
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String sURL; //File URL 05:?5M4};  
long nStartPos; //File Snippet Start Position _F8THYg (  
long nEndPos; //File Snippet End Position jZD)c_'U  
int nThreadID; //Thread's ID OG9 '[o`8  
boolean bDownOver = false; //Downing is over  aWPf3Q  
boolean bStop = false; //Stop identical bgxk:$E
 
FileAccessI fileAccessI = null; //File Access interface `<{LW>Lb  
" sC]z}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \SoT^PW  
{ e+V8I&%  
this.sURL = sURL; J/IRCjQ}  
this.nStartPos = nStart; 8L+A&^qx  
this.nEndPos = nEnd; y^z c@f  
nThreadID = id; 1nw\?r2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 TF9A4  
} et"Pb_-U  
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public void run() \d*ts(/a*  
{ \~g,;>%7Y  
while(nStartPos < nEndPos && !bStop) 'iTY?  
{ c8Q}m(bhWI  
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try{ 9J?lNq  
URL url = new URL(sURL); /EG'I{oC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o".,JnbXl  
httpConnection.setRequestProperty("User-Agent","NetFox"); '4_c;](W  
String sProperty = "bytes="+nStartPos+"-"; >bd@2au9!  
httpConnection.setRequestProperty("RANGE",sProperty); ~sZ$`t
 
Utility.log(sProperty); y+Hz(}4  
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1$+8wDVwad  
InputStream input = httpConnection.getInputStream(); R$+p4@?S  
//logResponseHead(httpConnection); }LeS3\+UHl  
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byte[] b = new byte[1024]; vw4b@v-XQ3  
int nRead; _-3n'i8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0n'vF&E8  
{ }%z%}V@(&  
nStartPos += fileAccessI.write(b,0,nRead); ;>L8&m)R5  
//if(nThreadID == 1) 0ckmHv  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bkc*it  
} hNhEA $X5  
{ 0-on"o  
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Utility.log("Thread " + nThreadID + " is over!"); z:$ibk4#h  
bDownOver = true; )P>/g*  
//nPos = fileAccessI.write (b,0,nRead); }Z{FPW.QK  
} !l=)$RJKdD  
catch(Exception e){e.printStackTrace ();} YCQ$X  
} uT'l.*W6i  
} ];lZ:gT  
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//打印回应的头信息 #
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public void logResponseHead(HttpURLConnection con) .#-F@0a  
{ Rk[a|T&  
for(int i=1;;i++) 6M.|W;  
{ \=7jp|{Yl  
String header=con.getHeaderFieldKey(i); Mm(#N/  
if(header!=null) %1:caa@_p  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -- FzRO{D  
Utility.log(header+" : "+con.getHeaderField(header)); JSi0-S[Y{  
else
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break; fIl!{pv[  
} Mn/@?K?y  
}
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public void splitterStop() k@un}}0r  
{ TYb$+uY  
bStop = true; `CH,QT7e  
} bc4V&  
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} }{VOyPG  
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)Z:D}r8[  
/* QF\nf_X  
**FileAccess.java Ei):\,Nv  
*//文件访问(定位，写) |oke)w=gn  
package NetFox; QxdC[t$Lp  
import java.io.*; B~N3k  
Qj;{Z*l%+  
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public class FileAccessI implements Serializable{ "GQ Q8rQ  
%^HE^
&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 fO&`A:JY  
RandomAccessFile oSavedFile; J (?qk  
long nPos; *dw.Ug  
bY=[ USgps  
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public FileAccessI() throws IOException GPK\nz
}  
{ vM6W64S  
this("",0); gWGDm~+  
} $q)YC.5$  
4minzrKM\  
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public FileAccessI(String sName,long nPos) throws IOException U
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{ Tk4>Jb  
oSavedFile = new RandomAccessFile(sName,"rw");
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this.nPos = nPos; j}eb _K+I  
oSavedFile.seek(nPos); DkEv1]6JI_  
} HyU:BW;  
rO$pj~!|Q  
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public synchronized int write(byte[] b,int nStart,int nLen) MCmb/.&wu  
{ xdm\[s  
int n = -1; robg1  
try{ 0^gY4qx[u  
oSavedFile.write(b,nStart,nLen); 1wKXOy=v0  
n = nLen; ^]nLE]M  
} ^ls@Gr7`P  
catch(IOException e) v62_VT2v  
{ Ze eV-  
e.printStackTrace ();
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} z6C(?R  
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_(F-(X|  
return n; )6C+0b*  
} dHXe2rTE;&  
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} p>`rTaeZg  
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1xW!j!A;  
/* B/1j4/MS  
**SiteInfoBean.java i
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*/ %S^hqC  
package NetFox; 05q760I+  
BsIF3sS#9  
[~s+,OO9)  
public class SiteInfoBean { QDg5B6>$  
@@Ybg6.+*  
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private String sSiteURL; //Site's URL $u!(F]^  
private String sFilePath; //Saved File's Path 1+;bd'Ie  
private String sFileName; //Saved File's Name }}=n]_f  
private int nSplitter; //Count of Splited Downloading File E]OexRJ^i  
F,wB6Cw  
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public SiteInfoBean() h#
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{//nSplitter的缺省值为5 B>^6tdz  
//default value of nSplitter is 5
n[iwi   
this("","","",5); ^?`fN'!p  
} Swhz\/u9  
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$72eHdy/yl  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) vPNbV  
{ My8d%GfM  
sSiteURL= sURL; l#KcmOz  
sFilePath = sPath; z4:!*:.Asu  
sFileName = sName; )A7^LLzG  
this.nSplitter = nSpiltter; 0!\C@wnH  
2`$*HPj+G  
gT+g@\u[
  
} a|7C6#iz$  
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public String getSSiteURL() @ep.wW  
{ N>H@vt~  
return sSiteURL; 3U@jw,K!{A  
}  !Ld5Y$  
~XTC:6ts  
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public void setSSiteURL(String value) J?8Mo=UZz  
{ BIWe Hx  
sSiteURL = value; d+q],\"R  
} duY?LJ@g  
i/9iM\2  
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public String getSFilePath() WywS1viD  
{ Dp([r  
return sFilePath; Tx;a2:6\[  
} =NF0E8O  
#rkq ?:Q  
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public void setSFilePath(String value) GTdoUSUq  
{ %biie  
sFilePath = value; {=Zy;Er  
} }4|EHhG  
~Gu$EqQ  
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public String getSFileName() <w2h@ea  
{ }=-0DSLVj  
return sFileName; '=_(fa,  
} yvYMk(LSF  
9
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public void setSFileName(String value) B6 0  
{ e(0OZ_w  
sFileName = value; (P|[<Sd  
} G4cgY|71  
 i0=U6S:#  
pe?)AiTZ:  
public int getNSplitter() 2l<2srEK  
{ >rd#,r  
return nSplitter; /$c8
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} EF`}*7)  
u} ot-!}Q  
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public void setNSplitter(int nCount) =:]ps<Qx  
{ h&>3;Lj  
nSplitter = nCount; cb}zCl j o  
} *[[Gu^t^!  
} d0(zB5'}  
m+(Cl#+  
vXJPvh<  
/* E8PDIjp  
**Utility.java UGcmzwE  
*/ 'ITq\1z  
package NetFox; Q~,Mzt"}W  
P<PZ4hNx  
sA2-3V<t8  
public class Utility { *Al@|5  
>d +
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public Utility() <z<>E1ZLI  
{ M"
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=[(34#  
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} }+@9[Q L  
MAek856  
//线程睡眠 o"VKAP  
public static void sleep(int nSecond) d[a(uWEl  
{ J,Sa7jv[  
try{ )WqolB  
Thread.sleep(nSecond); /qLO/Mim  
} 6 s=VU\  
catch(Exception e) 9!( 8o  
{ T\l`Y-vu  
e.printStackTrace (); *tXyd<_
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} p@tg pFt  
} @:>"VP<(  
mnpk9x}m  
//日志
X-["{  
public static void log(String sMsg) YG\#
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{ QEyL/#Q  
System.err.println(sMsg); 2"ax*MQH<^  
} ;(i6 X)  
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<M:BN6-yG  
public static void log(int sMsg) 7e"}ojt$  
{ 8['R D`O  
System.err.println(sMsg); :HY$x  
} JS/'0.  
} fL*7u\m:  
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^k6_j\5j  
/* \g}]u(zg%  
**TestMethod.java !5ps,+o  
*/ ~c)&9'  
package NetFox; a4*v'Xc5  
5u$.!l8Nl  
VF?H0}YSHb  
public class TestMethod { KFrsXf  
sfXFh  
3aqH!?rVU  
public TestMethod() SXL3>-Z E  
{ ///xx/weblogic60b2_win.exe digc7;8L  
try{ rq%]CsRY5  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7b"fpB  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
7#LIGr  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !*#9b  
fileFetch.start(); # -'A =j  
} lod+]*MD  
catch(Exception e){e.printStackTrace ();} m.<_WXH  
B!RfPk1B<*  
Fd9[Pe@?`  
} Ud/>oaW?s  
m\>gOTpA4  
07LyB\l~  
public static void main(String[] args) ~5HkDtI)  
{ ]Uv,}W  
new TestMethod(); L)'G_)Sl  
} <pX?x3-'  
} rL5=8l  
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