http断点续传简单实现（java)

/* 9}N*(PI  
**SiteFileFetch.java bu- RU(%  
*/ .@'Vz;&mQ  
package NetFox; EZ4qhda  
import java.io.*; J7ln6Y  
import java.net.*; k>"I!&#g  
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public class SiteFileFetch extends Thread { -SQYr  
 ~$B,K]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean P1<;:!8'  
long[] nStartPos; //开始位置 .JE7
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long[] nEndPos; //结束位置 M%/D:0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ts\7)6|F  
long nFileLength; //文件长度 6C:Lq%}  
boolean bFirst = true; //是否第一次取文件 >qCT#TY  
boolean bStop = false; //停止标志 0Ko,S(M_  
File tmpFile; //文件下载的临时信息 TR|; /yJ  
DataOutputStream output; //输出到文件的输出流 l-&f81W  
-nW-I\d%  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \iFE,z  
public SiteFileFetch(SiteInfoBean bean) throws IOException (ZYOm
  
{ @cON"(  
siteInfoBean = bean; \xt!b^d0  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 'py k  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #!2gxm;g  
if(tmpFile.exists ()) (w*$~p  
{ ?~!h N,h  
bFirst = false; &m`  
read_nPos(); =GF+hM/~  
} deNU[  
else 4{|lzo'&  
{ GCrN:+E0FJ  
nStartPos = new long[bean.getNSplitter()]; N`M5`=.  
nEndPos = new long[bean.getNSplitter()]; xK/`XY  
} wgrYZ^]  
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} #xmUND`@  
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public void run() {PU[MHZF  
{ ]n{2cPx5d  
//获得文件长度 E^g6,Y:i9  
//分割文件 #\}hN~@F  
//实例FileSplitterFetch X_h+\ 7N>  
//启动FileSplitterFetch线程 YXvKDw'95  
//等待子线程返回 .}tL:^'~o  
try{ HV}NT~
 
if(bFirst) Y !`H_Qo  
{ ]C!u~A\jq  
nFileLength = getFileSize(); 1yhx)m;f  
if(nFileLength == -1) !MbRI  
{ $z<CkMP!U7  
System.err.println("File Length is not known!"); ^C(AMT  
} F?UL0Q|uv  
else if(nFileLength == -2) #8PjYB  
{ !o`al` q'  
System.err.println("File is not access!"); vOqT Ld  
} j1BYSfX'  
else 62W3W1: W  
{ rTi.k  
for(int i=0;i<nStartPos.length;i++) ^#G>P0mG%  
{ })J]D~!p  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); wtZe
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} F*a+&% Q  
for(int i=0;i<nEndPos.length-1;i++) t<e?f{Q5  
{ s#4 "f  
nEndPos = nStartPos[i+1]; V@$B>HeK  
} 7B'0(70  
nEndPos[nEndPos.length-1] = nFileLength; Cnn,$R=/s  
} IRpCbTIXK  
} 9<R:)Df  
o:?I
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//启动子线程 hVd63_OO  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; QPBf++|  
for(int i=0;i<nStartPos.length;i++) +'[iyHBJ  
{ 3mx7[Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), blLX ncyD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ztu N0}'  
nStartPos,nEndPos,i); [\I\).  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P|G:h&  
fileSplitterFetch.start(); n|(Y?`(  
} 7Q^
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n.XT-X^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); poM VB{U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _N<8!(|w  
nEndPos = " + nFileLength); Z rvb %  
// fileSplitterFetch[nPos.length-1].start(); P/^:If
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//等待子线程结束 0n5N-b?G-@  
//int count = 0; `AY
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//是否结束while循环 HIF.;ImG^  
boolean breakWhile = false; oqG 0 @@  
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while(!bStop) v=|ahsYC  
{ rl!c\  
write_nPos(); `DEz ` D  
Utility.sleep(500); q'PA2a:  
breakWhile = true; w@hm>6j  
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for(int i=0;i<nStartPos.length;i++) X.g1 312~  
{ 0'a.Ypf  
if(!fileSplitterFetch.bDownOver) {AJspLcG  
{ L>cTI2NB.  
breakWhile = false; x H\5T!  
break; !)ee{CwNc  
} d6wsT\S  
} [03Aej  
if(breakWhile) 1
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break; x#'# ~EO-G  
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//count++; ZE4~rq/W  
//if(count>4) mlX^5h'  
// siteStop(); Fz-Bd*uS  
} -(~CZ  
-$t#
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NCBS=L:  
System.err.println("文件下载结束！"); `ez_ {  
} kAU[lPt*R  
catch(Exception e){e.printStackTrace ();} U^[<G6<9]  
} 7?e
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//获得文件长度 }VdohX-  
public long getFileSize() jeC3}BL}  
{ DjtUX>e  
int nFileLength = -1; nT9B?P>  
try{ &Zd!|u  
URL url = new URL(siteInfoBean.getSSiteURL()); h8Kri}z;M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6!O~:\`DJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); lkOugjI  
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int responseCode=httpConnection.getResponseCode(); 5^*I]5t8
 
if(responseCode>=400) mZ'`XAS~;  
{ X&pK#=  
processErrorCode(responseCode);
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return -2; //-2 represent access is error eVn]/.d  
} Bk*AO?3p  
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String sHeader; g&) XaF[!  
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for(int i=1;;i++) LDx1@a|83  
{ +.:- :  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); &V:iy  
//Utility.log(in.readLine()); gYw4YP0Gz  
sHeader=httpConnection.getHeaderFieldKey(i); z`y!C3w<  
if(sHeader!=null) ilHZx2k  
{ iO~3rWQ  
if(sHeader.equals("Content-Length")) <x *.M"6?  
{ ??Q'| r  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); tY~EB.%  
break; ~s
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} 3[amCKel  
} Z`Rrv$M!  
else Nyip]VwMJ  
break; uPQ:}zL
2  
} ^giseWR(  
} :>c33X
}  
catch(IOException e){e.printStackTrace ();} {}y"JbXM
j  
catch(Exception e){e.printStackTrace ();} 6=0"3%jn@  
by (xv0v;  
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Utility.log(nFileLength); Tq,Kel  
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return nFileLength; 0[/>> !ws  
} Y/?V%X  
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//保存下载信息（文件指针位置） aSkH<5i`v  
private void write_nPos() uS`XWn<CSD  
{ #(=8 RA:@  
try{ g4EC[>5!r  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $F"'=+0  
output.writeInt(nStartPos.length); Qyx%:PE  
for(int i=0;i<nStartPos.length;i++) SfLZVB  
{ "N>~]  
// output.writeLong(nPos); D
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output.writeLong(fileSplitterFetch.nStartPos); 3copJS  
output.writeLong(fileSplitterFetch.nEndPos); dZK/v  
} -fKo~\Pr  
output.close(); F9IrbLS9c  
} h fZY5+Z<  
catch(IOException e){e.printStackTrace ();} la+RK  
catch(Exception e){e.printStackTrace ();} E">FH>8K}  
} lA>^k;+>  
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//读取保存的下载信息（文件指针位置） C@1B?OfJ  
private void read_nPos() ]-]K4*{   
{ f9ux+XQk9  
try{ k+b!Lw!L  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); j
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int nCount = input.readInt(); dxfF.\BFDn  
nStartPos = new long[nCount]; /vO8s??  
nEndPos = new long[nCount]; =z#6mSx|W  
for(int i=0;i<nStartPos.length;i++) i[_B~/_  
{ '-c *S]:r  
nStartPos = input.readLong(); /6",#B}%b  
nEndPos = input.readLong(); |7ct2o~un  
} xU<WUfS1  
input.close(); W>W b|W  
} ?"04u*u3  
catch(IOException e){e.printStackTrace ();} )}w2'(!X8  
catch(Exception e){e.printStackTrace ();} PgHe;^?j  
} 5argw+2s4$  
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private void processErrorCode(int nErrorCode) 5XtIVHA@{  
{ fSc)PqLP  
System.err.println("Error Code : " + nErrorCode); t@r>GHO  
} ETZE.a  
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//停止文件下载 7]sRHX0o%  
public void siteStop() pNUe|b+P  
{ wH]5VltUT1  
bStop = true; =)b!M^=X-a  
for(int i=0;i<nStartPos.length;i++) O1+OE!w  
fileSplitterFetch.splitterStop(); )O+Vft&#  
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} 'k'"+  
} Z-%zR'-?*  
//负责部分文件的抓取 JsP<etX  
**FileSplitterFetch.java ;*(i}'  
*/
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package NetFox; ]?S@g'Jd0Q  
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import java.io.*; /aV;EkyO,  
import java.net.*; 5]f6YlJZ  
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public class FileSplitterFetch extends Thread { 8yCt(ms  
&c[ISc>N{  
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String sURL; //File URL 7m$EZTw?  
long nStartPos; //File Snippet Start Position Z1}@N/>>  
long nEndPos; //File Snippet End Position iWGn4p'  
int nThreadID; //Thread's ID o[^nmHrM2  
boolean bDownOver = false; //Downing is over ~Vt?'v20@  
boolean bStop = false; //Stop identical %fuV
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FileAccessI fileAccessI = null; //File Access interface 3QI.|;X  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3-/F]}0y6  
{ H|)F-aL[  
this.sURL = sURL; pJdR`A-k|  
this.nStartPos = nStart; ;IOM3'5T@  
this.nEndPos = nEnd; B@j2^Dr~!  
nThreadID = id; +lplQ
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 sEymwpm9  
} YMn*i<m  
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public void run() #fx>{ vzH  
{ CSwPL>tUV  
while(nStartPos < nEndPos && !bStop) 1,7  
{ 3ncN)E/@  
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try{ &j}:8Tst  
URL url = new URL(sURL); t i&!_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "T@9#7Obu  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'pnOHT  
String sProperty = "bytes="+nStartPos+"-"; K+\2cf?bU  
httpConnection.setRequestProperty("RANGE",sProperty); dL]wu!wE  
Utility.log(sProperty); CzDV^Iv;Q{  
;&dMtYb  
~_SRcM{  
InputStream input = httpConnection.getInputStream(); i@`qam   
//logResponseHead(httpConnection); %
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byte[] b = new byte[1024]; +!Q*ie+q  
int nRead; _vJ(F  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <2af&-EGs  
{ -}1TT@  
nStartPos += fileAccessI.write(b,0,nRead); 3a?|}zr4  
//if(nThreadID == 1) od)ssL&E~  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); []jbzVwS2  
} F'-,Ksn  
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Utility.log("Thread " + nThreadID + " is over!"); ?bAv{1dvT=  
bDownOver = true; s<+;5, Q|  
//nPos = fileAccessI.write (b,0,nRead); =O/v]B8"  
} *C);IdhK%y  
catch(Exception e){e.printStackTrace ();} Tb:6IC7="  
} ~ o=
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} U7''; w  
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//打印回应的头信息 F/PH=Dk  
public void logResponseHead(HttpURLConnection con) klAvi%^jE  
{ *xjP^y":  
for(int i=1;;i++) 388vdF  
{ v\@pZw=x  
String header=con.getHeaderFieldKey(i); Jj/}GVNc7  
if(header!=null) y=0)vi{]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); d}y")q|F  
Utility.log(header+" : "+con.getHeaderField(header)); nYR#Q|  
else OdpHF~(Y/  
break; ^T*!~K8A  
} aL*}@|JL"  
} OIK46D6?.  
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public void splitterStop() 6RG63+G  
{ ,^7]F"5
 
bStop = true; VsJKxa4  
} *aJO5&w<T  
 |e<$  
9 p,O>I  
} T^F83Py<  
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/* Be9,m
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**FileAccess.java xs&xcRR"  
*//文件访问(定位，写) q6ZewuV.  
package NetFox; k }{o: N  
import java.io.*; .Cf!5[0E  
L?Ys(a"k  
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public class FileAccessI implements Serializable{ 
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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 P,xIDj4d  
RandomAccessFile oSavedFile; ^?wR{q"8  
long nPos; 8#\|Y~P  
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t\h4-dJn  
public FileAccessI() throws IOException _Hd|y  
{ |Y8}*C\M.h  
this("",0); 1szObhN-l  
} 4l{$dtKbI  
93Zij<bH?e  
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public FileAccessI(String sName,long nPos) throws IOException sgDSl@lB  
{ rB{w4  
oSavedFile = new RandomAccessFile(sName,"rw"); &4+|{Zx0  
this.nPos = nPos; 0b/@QgJ  
oSavedFile.seek(nPos); {bADMj1  
} _n/73Oh  
C\joDAD  
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public synchronized int write(byte[] b,int nStart,int nLen) OrYN-A4{
 
{ //;(KmU9  
int n = -1; Hq+QsplG  
try{ d3|/&gDBK  
oSavedFile.write(b,nStart,nLen); (w{T[~6  
n = nLen; Mk0x#-F  
} '6})L  
catch(IOException e) 7{(UiQbf  
{ KK
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e.printStackTrace (); fm@Pa} ,  
} _5H~1G%q  
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return n; jf-XVk5q  
} uI9*D)  
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?  
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} x.Egl4b3  
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FZO&r60$E  
/* h`n '{s  
**SiteInfoBean.java jpO0dtn3=  
*/ KS<@;Tt  
package NetFox; :V5 Co!/+  
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public class SiteInfoBean { cc*?4C/t  
4].o:d;`/  
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private String sSiteURL; //Site's URL b_ak@LYiu  
private String sFilePath; //Saved File's Path 6r`N\ :18  
private String sFileName; //Saved File's Name FZn1$_Svr  
private int nSplitter; //Count of Splited Downloading File B`<}YVA  
vPGUE`!D+  
z@,(^~C_  
public SiteInfoBean() Z$g'h1,zW  
{//nSplitter的缺省值为5
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//default value of nSplitter is 5 [5p3:D  
this("","","",5); u<uc"KY=  
} T7"QwA  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n@ SUu7o  
{ %3~miP  
sSiteURL= sURL; qR!ZtJ5j  
sFilePath = sPath; k}F7Jw#.  
sFileName = sName; Jz>P[LcB  
this.nSplitter = nSpiltter; Z^2SG
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x?V^l*  
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} %hN>o)  
P7b"(G%  
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public String getSSiteURL() >qB`03>  
{ ULxQyY;32  
return sSiteURL; $*G3'G2'iS  
} p0 X%^A,4  
zl6]N3+4  
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public void setSSiteURL(String value) ?wPTe^Qtv  
{ #7Q9^rG  
sSiteURL = value; i a!!jK}  
} ]|eMEN['  
 q/ Y4/  
\t1#5  
public String getSFilePath() kJJiDDL0;*  
{ G-2~$ u  
return sFilePath; q[VQ?b~9  
} l"E{ ?4  
}dzVwP=  
p?>J86%[  
public void setSFilePath(String value) )K@D4sl  
{ e-P{)L<s5  
sFilePath = value; H[p~1%Lq  
} Ar~/KRK  
-rI7ihr*  
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public String getSFileName() J)B3o$  
{ "lu^  
return sFileName; MYvz%7  
} FS&QF@dtgf  
1aO(+](;  
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public void setSFileName(String value) 'l<$H=ZUVG  
{ 0ZDm[#7z  
sFileName = value; }v2p]D5n.  
} YToG'#qs  
d*Su c  
/nA>ox78  
public int getNSplitter() 5I6?gv/  
{ S+[,\>pY  
return nSplitter; ]^.`}Y=`g  
} *~6]IWN`  
q`{@@[/(y  
w9GY/]  
public void setNSplitter(int nCount) 75^*4[  
{ Gdb0e]Vt+  
nSplitter = nCount; 5)S;R,  
} A\rY~$Vr  
} T_c`=3aO  
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?  
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/* 9NVtvBA  
**Utility.java [_xOz4
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*/ <:/aiX8  
package NetFox; v"(6rZsa  
#S/~1{  
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public class Utility { p+b9D  
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public Utility() 3=ME$%f  
{ rjc
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} T<7}IH$6xE  
E#m^.B-}  
//线程睡眠 YK8l#8K  
public static void sleep(int nSecond) `k
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{ "[["naa  
try{ wjX0r7^@  
Thread.sleep(nSecond); h6LjReNo  
} 1iR\M4?Frf  
catch(Exception e) #Qz9{1\G  
{ K ~\b+  
e.printStackTrace (); EiM\`"o  
} !$iwU3~<  
} Z%.Ld2Q{  
x?{l<m
c  
//日志 lxXF8c>U  
public static void log(String sMsg) NPBOG1q%  
{ +gndW  
System.err.println(sMsg); C|FI4/-e  
} M-QQ  
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u8A,f}D 3  
public static void log(int sMsg) L~|_)4  
{ O>rz+8T  
System.err.println(sMsg); &JLKHwi/  
} NODE`VFu  
} ct*~\C6Ze  
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7[kDc-  
/* C\C*@9=&x  
**TestMethod.java 0""%@X]m  
*/ ;erx
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package NetFox; yP@#1KLa+  
YL;*%XmAG  
=}0>S3a.7  
public class TestMethod { \@ZD.d#  
q,Nqv[va  
aFrZ ;_  
public TestMethod() 0_>1CW+X  
{ ///xx/weblogic60b2_win.exe f]Z9=  
try{ Pa\yp?({q  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); G7-.d/8|^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O'k<4'TC  
SiteFileFetch fileFetch = new SiteFileFetch(bean); )u!}`UJ  
fileFetch.start(); jw2hB[WR  
} "[L+LPET  
catch(Exception e){e.printStackTrace ();} `kOp9(Q{  
i}:^<jDv?  
x?R1/i
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} 2F1Bz<  
,`ehR6b  
QA!'p1{#  
public static void main(String[] args) M|z4Dy  
{ .0y .0=l  
new TestMethod(); viS7+E|O  
} )lx;u.$4  
} Q?m= a0g  
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