http断点续传简单实现（java)

/* $t;:"i>  
**SiteFileFetch.java #%;Uh  
*/ .]vb\N
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package NetFox; ~b
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import java.io.*; j9h/`Bn  
import java.net.*; 0DicrnH8  
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public class SiteFileFetch extends Thread { d0 )725Ia  
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SiteInfoBean siteInfoBean = null; //文件信息Bean K ";Et  
long[] nStartPos; //开始位置 ;g!rc#z2g  
long[] nEndPos; //结束位置 Q-oDmjU  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 '.bf88D  
long nFileLength; //文件长度 TTVmm{6  
boolean bFirst = true; //是否第一次取文件 L(;$(k-/(  
boolean bStop = false; //停止标志 O{l4 f:51  
File tmpFile; //文件下载的临时信息 zTa5N  
DataOutputStream output; //输出到文件的输出流 ,JZ>)(@)  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） x &R9m,  
public SiteFileFetch(SiteInfoBean bean) throws IOException QR&e~rks  
{ _^BA;S@  
siteInfoBean = bean; ^K<3_D>1>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ur])*#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,4Q4{Tx  
if(tmpFile.exists ()) RzqgN*]lY  
{ -hXKCb4YU  
bFirst = false; T aS
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read_nPos(); KkCGL*]K  
} |cU75 S1  
else C
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{ o`iA&  
nStartPos = new long[bean.getNSplitter()]; l5T[
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nEndPos = new long[bean.getNSplitter()]; @}4aF|  
} P2'N4?2  
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} kkjugm{D7  
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public void run() }MQ:n8  
{ Og1-LP|X  
//获得文件长度 \U$:/#1Oe  
//分割文件 v[Q)L!J1  
//实例FileSplitterFetch i#la'ICwJ  
//启动FileSplitterFetch线程 QCb
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//等待子线程返回 %R>n5m  
try{ 1Vu#:6%  
if(bFirst) e`n ZiM>  
{ >/A]C$?3  
nFileLength = getFileSize(); hoq2zDjD  
if(nFileLength == -1) c& ;@i$X(  
{ ..JRtuM-v  
System.err.println("File Length is not known!"); U823q-x  
} M8~3 0L  
else if(nFileLength == -2) #s{^fUN6  
{ '{ _ X1  
System.err.println("File is not access!"); \\R}3 >Wc  
} E]' f&0s  
else (u&x.J  
{ Or? )Nlg6x  
for(int i=0;i<nStartPos.length;i++) 7FE36Ub9  
{ ;dzL9P9IU  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); KUJLx  
} R,BJr y  
for(int i=0;i<nEndPos.length-1;i++) Z[nHo'  
{ p}QDX*/sSu  
nEndPos = nStartPos[i+1];  WwB_L.{  
} [OCjYC`  
nEndPos[nEndPos.length-1] = nFileLength; e{E\YEc  
} 2fTuIS<yr  
} 86=W}eV1r  
blQ
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//启动子线程 MDF_Xr-hZ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; O(/~cQ  
for(int i=0;i<nStartPos.length;i++) }&vD(hX  
{ yP{ 52%|+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !Aj}sh{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >Hnm.?-AWl  
nStartPos,nEndPos,i); V[(fE=cIN~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'W(u.  
fileSplitterFetch.start(); xq((]5Py  
} GURiW42  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~]-n%J$q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M G$+
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", iE''>Z  
nEndPos = " + nFileLength); T_S3_-|{==  
// fileSplitterFetch[nPos.length-1].start(); v*!N}1+J  
+;~N; BT  
"s0,9; }  
//等待子线程结束 (vG*)a  
//int count = 0; 46g0 e  
//是否结束while循环 'JOCL0FP  
boolean breakWhile = false; gO8d2?Oh  
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while(!bStop) E4% -*n  
{ 5f7id7SI  
write_nPos(); |<u+Xi ~  
Utility.sleep(500); %'1iT!g8  
breakWhile = true; KVOV<uDCj  

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 2 q4p-  
for(int i=0;i<nStartPos.length;i++) 9K@I  
{ &\9%;k  
if(!fileSplitterFetch.bDownOver) f- XUto  
{ &<;T$Y  
breakWhile = false; vqN/crJ@  
break; DP@1to@  
} HFFG4'  
} DT`HS/~fH  
if(breakWhile) ;}SGJ7  
break; Ye3o}G9z  
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//count++; |N`0
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//if(count>4) dNgA C){w  
// siteStop(); kU/MvoV  
} Nud =K'P=  
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System.err.println("文件下载结束！"); vcFR Td  
} 'd~(=
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catch(Exception e){e.printStackTrace ();} VZt%cq  
} Wo "s;Z  
S' $;  
!\7M7  
//获得文件长度 kf'(u..G  
public long getFileSize() mFTuqujO  
{ iF+:j8 b  
int nFileLength = -1; g8.z?Ia#5Z  
try{ IB&G#2M<  
URL url = new URL(siteInfoBean.getSSiteURL()); /ugWl99.W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8|zavH#P  
httpConnection.setRequestProperty("User-Agent","NetFox"); iHhdoY[]  
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int responseCode=httpConnection.getResponseCode(); C~T,[U  
if(responseCode>=400) 4*}
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{ 2A\b-;4EP  
processErrorCode(responseCode); r<ww%2HTS
 
return -2; //-2 represent access is error LL e*|:  
} p/(Z2N"  
#$Zx].[lc  
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String sHeader; (e'8>Pv  
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for(int i=1;;i++)
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{ Md~SzrU  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vS
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//Utility.log(in.readLine()); 6m$X7;x}  
sHeader=httpConnection.getHeaderFieldKey(i); ?7Cm+J  
if(sHeader!=null) =Smd/'`_  
{ J+t51B(a  
if(sHeader.equals("Content-Length")) c~tl0XU1  
{ &j:e<{@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /C8}5)  
break; r{.pXf  
} F2 B(PGa7  
} ;\w3IAa|V  
else o:{Sws(=  
break; nx%As  
} 8p 4[:M@  
} pK-tj  
catch(IOException e){e.printStackTrace ();} YA pC|R,^  
catch(Exception e){e.printStackTrace ();} z6U'"T"a  

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Utility.log(nFileLength); /!
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return nFileLength; 0s-K oz  
} !AXLoq$SY  
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//保存下载信息（文件指针位置） {x
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private void write_nPos() 'l(s)Oa{M:  
{ 8|@) #:  
try{ iN8[^,2H|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); d_we?DZ|  
output.writeInt(nStartPos.length); 'a0M.*f}G  
for(int i=0;i<nStartPos.length;i++) .I~:j`K6  
{ L|WrdT D;  
// output.writeLong(nPos); 60|PVsmDm  
output.writeLong(fileSplitterFetch.nStartPos); 4AEw[(t  
output.writeLong(fileSplitterFetch.nEndPos); |kh{EUE ;  
} HXT"&c|  
output.close(); Mlc_w19C9  
} a0)w/A&  
catch(IOException e){e.printStackTrace ();} O\f`+Q`0  
catch(Exception e){e.printStackTrace ();} }IWt\a<d  
} Yr{hJGw[  

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8SRUqe[H]  
//读取保存的下载信息（文件指针位置） fNi&r0/-t  
private void read_nPos() ,ASNa^7/>  
{ 4v>SXch  
try{ `^/8dIya  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ub f5:  
int nCount = input.readInt(); P<X?  
nStartPos = new long[nCount]; Khd A;bF  
nEndPos = new long[nCount]; *g
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for(int i=0;i<nStartPos.length;i++) pNd`fV#jX  
{ #C }+  
nStartPos = input.readLong(); I
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nEndPos = input.readLong(); }O+xs3Uv  
} iPl,KjGk  
input.close(); <xSh13<  
} &-FG}|*4M  
catch(IOException e){e.printStackTrace ();} (b~l.@xh  
catch(Exception e){e.printStackTrace ();} \},H\kK+^  
} -3yK>\y=|  
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private void processErrorCode(int nErrorCode) (z8ZCyq7r[  
{ vcj(=\ e8v  
System.err.println("Error Code : " + nErrorCode); !i8)si_  
} qN1fWU#$  
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ShL!7y*rT{  
//停止文件下载 i/*)1;xsk  
public void siteStop() dH5*%  
{ hN K wQ  
bStop = true; 43h06X`  
for(int i=0;i<nStartPos.length;i++) HqsqUS3[  
fileSplitterFetch.splitterStop(); [2xu`HT02  
9Vq  
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} h8O\sKn  
} VDOC>  
//负责部分文件的抓取 @7"n X  
**FileSplitterFetch.java wz3X;1l`c  
*/ Jc?zX8>Ae:  
package NetFox; G~C-tAB  
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import java.io.*; Q?T+^J   
import java.net.*; (KN",u6F  
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public class FileSplitterFetch extends Thread { kF'9@*?J  
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String sURL; //File URL +dLUq2  
long nStartPos; //File Snippet Start Position ShVR{gIs  
long nEndPos; //File Snippet End Position Wn6m$=  
int nThreadID; //Thread's ID ]r!|@AWrQ\  
boolean bDownOver = false; //Downing is over c.1gQy$}|  
boolean bStop = false; //Stop identical JE{cZ<NNH  
FileAccessI fileAccessI = null; //File Access interface 2hNl_P~z1u  
jFg19C{=X  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >{(c\oMD  
{ k(tB+k!vH\  
this.sURL = sURL; !21G$[H  
this.nStartPos = nStart; UVLS?1ra  
this.nEndPos = nEnd; CLZj=J2  
nThreadID = id; >0:3CpO*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 O[$X36z  
} n~ $S  
aC=2v7*  
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public void run() #tUhul/O  
{ TDfloDxA  
while(nStartPos < nEndPos && !bStop) `qd5+~c  
{ m Qx1co  
.<%q9Jy#  
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try{ KXx;~HtO  
URL url = new URL(sURL); $#/8l58  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z%ZOAu&p  
httpConnection.setRequestProperty("User-Agent","NetFox");  :Kyr}-  
String sProperty = "bytes="+nStartPos+"-"; BQUYT/$(  
httpConnection.setRequestProperty("RANGE",sProperty); +KExK2=  
Utility.log(sProperty); 3ONWu  
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InputStream input = httpConnection.getInputStream(); o6 NmDv5  
//logResponseHead(httpConnection); %#4;'\'5  
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byte[] b = new byte[1024]; 
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int nRead; aH%tD!%,o  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Dz.kJ_"Ro  
{ NI:OL  
nStartPos += fileAccessI.write(b,0,nRead); |9 *$6Y  
//if(nThreadID == 1) yTbtS-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K; hP0J  
} }Dcpe M?  
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Utility.log("Thread " + nThreadID + " is over!"); 2y$DTMu  
bDownOver = true; uU$/4{  
//nPos = fileAccessI.write (b,0,nRead); ](-[ I#  
} v{lDEF@2^N  
catch(Exception e){e.printStackTrace ();} v(O@~8(I  
} @DM NLsQ  
} +LWgby4q  
# 6?2 2Os  
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//打印回应的头信息 `.VkR5/  
public void logResponseHead(HttpURLConnection con) PMQ31f/zf  
{ c}=[r1M*  
for(int i=1;;i++) &,XPMT  
{ |M<R{Tt}nf  
String header=con.getHeaderFieldKey(i); 3!*`hQ;s  
if(header!=null) zhRF>Y`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |`wJ {-  
Utility.log(header+" : "+con.getHeaderField(header)); yYk?K<ou  
else T8T,G4Q  
break; _mQ~[}y+?  
} k ;vOPcw  
} z;YX2G/{  
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public void splitterStop() -Vg0J6x  
{ UU =,Brb  
bStop = true; pek5P4W_  
} kc2E4i  
{;UBW7{  
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} z"sv,W  
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/* Q6X}R,KA1  
**FileAccess.java -Xgup,}?  
*//文件访问(定位，写) 7BA9zs392  
package NetFox; h7]>b'H  
import java.io.*; 5FNf)F   
p_3VFKq>0  
7.^1I7O  
public class FileAccessI implements Serializable{ \w{fq+G  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 U@:iN..  
RandomAccessFile oSavedFile; BS3BJwf; f  
long nPos; T:j!a{_|  
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public FileAccessI() throws IOException ~65lDFY/  
{ ]7dal [i  
this("",0); @(tiPV  
} ==7=1QfP  
8\Z/mU*4  
O~#OVFJ9=  
public FileAccessI(String sName,long nPos) throws IOException CH h6Mnw  
{ Y2p~chx9  
oSavedFile = new RandomAccessFile(sName,"rw"); 5th\_n}N2/  
this.nPos = nPos; oxqD/fY  
oSavedFile.seek(nPos); YC~kq?  
} p7
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:}w^-I"  
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public synchronized int write(byte[] b,int nStart,int nLen) Zo(QU5m0  
{ 7\;gd4Ua1  
int n = -1; fm%-wUgj  
try{ Op<|Oz$Q|l  
oSavedFile.write(b,nStart,nLen);
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n = nLen; ] i\a[3  
} ;6zp,t0  
catch(IOException e) ?#;zB  
{ @)wNINvD  
e.printStackTrace (); i_;]UvP  
} *8QGv6*vQ  
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return n; d`+cNKf  
} >*mLbp"  
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/* s*j0uAq)up  
**SiteInfoBean.java sh"\ kk9  
*/ 2L_ts=  
package NetFox; bMw)>4  
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public class SiteInfoBean { [0e}%!%M  
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private String sSiteURL; //Site's URL 9m fYB  
private String sFilePath; //Saved File's Path .ZrQ{~t  
private String sFileName; //Saved File's Name OC]_b36v  
private int nSplitter; //Count of Splited Downloading File }A"%YDrNbG  
Y<S,Xr;J:  
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public SiteInfoBean() %h%^i   
{//nSplitter的缺省值为5 <vV?VV([  
//default value of nSplitter is 5 { O*maE"  
this("","","",5); d(L u|/~  
} b='YCa  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {^bs }($J  
{ h^5'i}@u  
sSiteURL= sURL; 1qb
3.  
sFilePath = sPath; E0}jEl/
{  
sFileName = sName; bd2"k;H<o  
this.nSplitter = nSpiltter; P$\vD^  
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<Ep-aRI  
} b&!7(Q[ sT  
(6G5UwSt  
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public String getSSiteURL() #$Z|)i]w  
{ 94F9f^ L  
return sSiteURL; j%KLp4J/e  
} 16YJQ ue  
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, c/\'k\K)  
public void setSSiteURL(String value) _Ucj)Ud k  
{ !_cT_ WHty  
sSiteURL = value; mIZ#uW  
} 9frS!AQ  
AtA}OY]D/  
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public String getSFilePath() xgtdmv%  
{ 8_ns^6XK5p  
return sFilePath; 52>?l C  
} pVw)"\S%  
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public void setSFilePath(String value) vGC^1AM  
{ G)?O!(_  
sFilePath = value; 0QDm3V0n  
} "@E1^
  
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public String getSFileName() /cr.}D2O  
{ gR(*lXm5w  
return sFileName; M,PZ|=V6a  
} BjJ$I^  
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public void setSFileName(String value) xk}YeNVj  
{ ~/hP6*  
sFileName = value; -X Bh\w  
} 7k:}9M~  
?PSm) ~Oa  
rBkf@  
public int getNSplitter() Q4Q*5>  
{ 'j!7 O+7y  
return nSplitter; 6pQ#Zg()vp  
} VD.p"F(]  
!w98[BE7  
+tOBt("5/  
public void setNSplitter(int nCount) s%J|r{F6  
{ abCcZ<=|b  
nSplitter = nCount; ?4_^}B9  
} z8= Gc$w!  
} >OwVNG  
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*
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/* !/['wv@  
**Utility.java W<B8PS$  
*/ =[?2'riI  
package NetFox; 'e\m6~u\hm  
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public class Utility { xue-5 '  
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public Utility() ^Y~ ,s  
{ F1)Q#ThF\  
Y1Bj++?2  
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} l@<^V N@  
E[6JHBE*r  
//线程睡眠 >RBq&'f  
public static void sleep(int nSecond) OcMd'fwO  
{ +:~&"U^z&  
try{ @iy ^a  
Thread.sleep(nSecond); )"jG)c^1*  
} }vx
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catch(Exception e) hX 9.%-@sR  
{ 7|T5N[3?l,  
e.printStackTrace (); @C7S^|eo  
} m^O:k"+!  
} McxJ C<  
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//日志 .?_wcp=  
public static void log(String sMsg) ay'=M`uO_  
{ Cr4shdN34  
System.err.println(sMsg); HHCsWe-  
} 8b(UqyV  
]NuY{T&:  
-d%bc?  
public static void log(int sMsg) 5cxA,T  
{ v.cB3/$z  
System.err.println(sMsg); :{LVS nG  
} ~0|~Fg  
} 1F/`*z
 
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/* (bH"x  
**TestMethod.java [G[HQ)A  
*/ vV#Jl)
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package NetFox; |j^>6nE  
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public class TestMethod { >efYpd#^  
0$}+tq+  
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public TestMethod() uMP
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{ ///xx/weblogic60b2_win.exe 5^GUuFt5m  
try{ *J8j_-i,R  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /_x?PiL  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~Rk6@&ZS}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2p@Rr7  
fileFetch.start(); Xn$]DE/r}N  
} I@+dE V`Lf  
catch(Exception e){e.printStackTrace ();} k-Jj k3  
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} sA3 4`ZAa  

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public static void main(String[] args) U,[vfSDGr  
{ yFl@z  
new TestMethod(); 9d#-;qV  
} 1f~unb\Gg  
} o`M7:8G  
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