http断点续传简单实现（java)

/* PPCZT3c=  
**SiteFileFetch.java wEK@B&DV  
*/ &dSw[C#f  
package NetFox; {},rbQ -  
import java.io.*; HLMEB0zh^  
import java.net.*; c`UJI$Q/

 
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public class SiteFileFetch extends Thread { b@J&jE~d  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Ty]/F+{  
long[] nStartPos; //开始位置 !=#2
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long[] nEndPos; //结束位置 5G8`zy  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Z-m,~Hh  
long nFileLength; //文件长度 SM:SxhrGt  
boolean bFirst = true; //是否第一次取文件 fTi,S)F'  
boolean bStop = false; //停止标志 Xq&x<td  
File tmpFile; //文件下载的临时信息
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DataOutputStream output; //输出到文件的输出流 t`{^gt  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） K[LTw_oE  
public SiteFileFetch(SiteInfoBean bean) throws IOException %g(h%V9f  
{ w $7J)ngA9  
siteInfoBean = bean; ?U0iHg{  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .kM74X=S  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); (^g?/i1@d  
if(tmpFile.exists ()) 9E_C u2B  
{ 3uwZ#   
bFirst = false; $1(u.Ud  
read_nPos(); V|NWJ7  
} JbYv
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else [|{yr  
{ d"78w-S  
nStartPos = new long[bean.getNSplitter()]; Co8b0-Z  
nEndPos = new long[bean.getNSplitter()]; 5| 2B@6-  
} 9frx
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} {Ny\9r  
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public void run() k>{i_`*  
{ uVqJl{e\  
//获得文件长度 s<qSelj  
//分割文件 :o$ R@l  
//实例FileSplitterFetch @u/<^j3Q  
//启动FileSplitterFetch线程 e#k9}n^+  
//等待子线程返回 <9bQAyL9  
try{ c>K/f7  
if(bFirst) PKC``+Ki  
{ K_nN|'R-  
nFileLength = getFileSize(); !U]V?Jpi"  
if(nFileLength == -1) CTtF=\  
{  49 3ik  
System.err.println("File Length is not known!"); u0$7k9mE  
} sXTt)J  
else if(nFileLength == -2) ]^gD@]
.  
{ }M/w 0U0o  
System.err.println("File is not access!"); y{ 90A  
} o<-%)#e  
else nvD"_.KrJ  
{ 1L'[DKb'  
for(int i=0;i<nStartPos.length;i++) ?w# >Cs(  
{ sVkR7 ^KsG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); XrC{{K  
} "<6pp4*I  
for(int i=0;i<nEndPos.length-1;i++) [RD ^@~x  
{ !gy'_Y  
nEndPos = nStartPos[i+1]; aEdFZ  
} <-Q0WP_^  
nEndPos[nEndPos.length-1] = nFileLength; +,>f-kaV  
} 0s0[U  
} 5HG 7M&_  
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//启动子线程 p"H8;fPA0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r_xo>y~S  
for(int i=0;i<nStartPos.length;i++) O( h
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{ ~B(]0:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d5A!kU _.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), = k3O4gE7  
nStartPos,nEndPos,i); q~trn'X>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |!%A1 wp#  
fileSplitterFetch.start();
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} QVn0!R{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); U]R?O5K  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8tA.d.8  
nEndPos = " + nFileLength); [tMf KO  
// fileSplitterFetch[nPos.length-1].start(); + y.IDn^  
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//等待子线程结束 )[oU|
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//int count = 0; *BXtE8 BU  
//是否结束while循环 RMC|(Q<  
boolean breakWhile = false; `N(.10~  
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while(!bStop) ? |8&!F  
{ ,zXL8T  
write_nPos(); #EHBS~^  
Utility.sleep(500); YGWb!|Z$  
breakWhile = true; +1d\ZZA|6&  
#-'}r}1ZT  
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for(int i=0;i<nStartPos.length;i++) =V5.c+  
{ .yTk/x?  
if(!fileSplitterFetch.bDownOver) sF+0v p  
{ IJ4"X#Q/  
breakWhile = false; lR.a3.~  
break; 1.,mNY^UN  
} e_1mO 5z  
} ,dVCbAS@  
if(breakWhile) c6c^9*,V  
break; nrt0[E-&~  
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//count++; W77JXD93  
//if(count>4) #eUfwd6.Y  
// siteStop(); p,tB  
} xZ@Y`2A':  
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System.err.println("文件下载结束！"); raqLXO!j  
} 3$Is==>7  
catch(Exception e){e.printStackTrace ();} I.8|kscM  
} 0'py7  
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//获得文件长度 L/
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public long getFileSize() 5ef&Ih.3  
{ mlVv3mVyR<  
int nFileLength = -1; @\"*Z&]8z0  
try{  g u|;C  
URL url = new URL(siteInfoBean.getSSiteURL()); _O!D*=I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >}4]51s  
httpConnection.setRequestProperty("User-Agent","NetFox"); )F~>  
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int responseCode=httpConnection.getResponseCode(); <khx%<)P  
if(responseCode>=400) vlPE8U=  
{ J,D{dYLDD  
processErrorCode(responseCode); &U=f,9H  
return -2; //-2 represent access is error |
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} gMGg9U$@  
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String sHeader; GDcV1$NA  
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for(int i=1;;i++) }cPV_^{  
{ {``}TsN  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?+|tPjg$  
//Utility.log(in.readLine()); Bjo&  
sHeader=httpConnection.getHeaderFieldKey(i); 0ay!tS dN  
if(sHeader!=null) IWWFl6$-  
{ kdHql>0  
if(sHeader.equals("Content-Length")) sN g"JQ  
{ `UI)H*GA8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); > Qtyw.n  
break; gK<-*v  
} h4qR\LX  
} 7 %|>7  
else 19rUvgC{M  
break; +>3c+h,%.  
} rx;U/)~#<  
} X3-1)|g !z  
catch(IOException e){e.printStackTrace ();} nB]Q^~jX  
catch(Exception e){e.printStackTrace ();} X,N@`  
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Utility.log(nFileLength); BE+YqT  
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return nFileLength; +|H'Ij$  
} 6wd]X-G++  
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//保存下载信息（文件指针位置） "n e'iJf_(  
private void write_nPos() *]eZ Y  
{ q kKABow  
try{ 
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output = new DataOutputStream(new FileOutputStream(tmpFile)); y2U:( H:l!  
output.writeInt(nStartPos.length); kb:C>Y8!sC  
for(int i=0;i<nStartPos.length;i++) bn`zI~WS  
{ c[y8"M5  
// output.writeLong(nPos); 1v4kN -  
output.writeLong(fileSplitterFetch.nStartPos); cR&xl^BJ  
output.writeLong(fileSplitterFetch.nEndPos); #TW
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} nGbrWu]w  
output.close(); sy?>e*-{  
} !kcg#+s91  
catch(IOException e){e.printStackTrace ();} .'a|St  
catch(Exception e){e.printStackTrace ();} Za6oYM_z  
} Hj\~sR$L-  
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//读取保存的下载信息（文件指针位置） qLP+@wbJ  
private void read_nPos() asi1c y\  
{ X]fw9tZ  
try{ V~_nyjrJM  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); S8=4C`>jf  
int nCount = input.readInt(); m?j!0>  
nStartPos = new long[nCount]; 9C$!tz>>+i  
nEndPos = new long[nCount]; #{M -3  
for(int i=0;i<nStartPos.length;i++) 5a ~tp'  
{ *o[%?$8T  
nStartPos = input.readLong(); jvV8`BQ{  
nEndPos = input.readLong(); z~H Gc"~  
} injmP9ed  
input.close(); X w8il  
} H5s85"U#  
catch(IOException e){e.printStackTrace ();} 8j'*IRj*q  
catch(Exception e){e.printStackTrace ();} 752wK|o0|;  
} vdm?d/0(^  
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private void processErrorCode(int nErrorCode) FJLJ;]`7+  
{ kpH;D=;  
System.err.println("Error Code : " + nErrorCode); Q 8rtZ  
} R`Lm"5w  
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//停止文件下载 E(tBN]W.  
public void siteStop() )sf~l6  
{ {h"\JI!  
bStop = true; @__;RVQ  
for(int i=0;i<nStartPos.length;i++) Nd_@J&  
fileSplitterFetch.splitterStop(); `
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} tTGK25&  
} 
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//负责部分文件的抓取 (UF!Zb]{  
**FileSplitterFetch.java Gme$FWa  
*/ F}]_/cY7B  
package NetFox; Q:O>kCDV  
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import java.io.*; L"iyjL<M  
import java.net.*; ~ ZL`E  
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public class FileSplitterFetch extends Thread { XO#)i6}G  
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String sURL; //File URL ,)$KS*f"*z  
long nStartPos; //File Snippet Start Position 38rZ`O*D  
long nEndPos; //File Snippet End Position 5|CiwQg|,p  
int nThreadID; //Thread's ID 3\n{,Q  
boolean bDownOver = false; //Downing is over #( sNk,^Ax  
boolean bStop = false; //Stop identical =&pN8PEn\  
FileAccessI fileAccessI = null; //File Access interface &fW=5'  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException L~{Vt~H9"  
{ Qe$>Jv5  
this.sURL = sURL; !>< %\K  
this.nStartPos = nStart; o#P3lz  
this.nEndPos = nEnd; {p|%hhTK%  
nThreadID = id; /:` i%E  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 WKl'  
} kqW<e[  
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public void run() !t Oky  
{ g&3#22z  
while(nStartPos < nEndPos && !bStop) uq4sbkP  
{ dB+GT
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try{ I'9s=~VfY,  
URL url = new URL(sURL); fq'Xy9L  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AdEbyL  
httpConnection.setRequestProperty("User-Agent","NetFox"); r?nV Sb|[  
String sProperty = "bytes="+nStartPos+"-"; 'UVv(-  
httpConnection.setRequestProperty("RANGE",sProperty); @CU|3Qg  
Utility.log(sProperty); (+LR u1z  
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InputStream input = httpConnection.getInputStream(); mBZDl4 '  
//logResponseHead(httpConnection); "QO/Jls  
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byte[] b = new byte[1024]; @
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int nRead; wUCDJY:,1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :"P hkR  
{ ]KK ZbEO  
nStartPos += fileAccessI.write(b,0,nRead); :aq>  
//if(nThreadID == 1) /QXs-T}d  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aE\B
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} '}+X,Usm  
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Utility.log("Thread " + nThreadID + " is over!"); ?>.g;3E$  
bDownOver = true; 9LEilmPs  
//nPos = fileAccessI.write (b,0,nRead); id tQXwa  
} te*Y]-&I|/  
catch(Exception e){e.printStackTrace ();} <,pLW~2-"  
} C6'*/wq  
} 8gtCY~m  
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//打印回应的头信息 HS`bto0*  
public void logResponseHead(HttpURLConnection con) i9\\evJs  
{ 12d}#G<q-  
for(int i=1;;i++) %wjB)Mae  
{ :uwRuPI  
String header=con.getHeaderFieldKey(i); mrhp)yF  
if(header!=null) @oz&  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 22/?JWL>  
Utility.log(header+" : "+con.getHeaderField(header)); 9j?hF$L"  
else QR5,_wJ&  
break; (: TGev  
} UiK+c30FU  
} K"k"ml<4E  
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public void splitterStop() k~jKJb-_  
{ L_gsG|xX  
bStop = true; < k+fKl  
} QK?2E  
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} *)NR$9lGv  
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/* F/h:&B:;  
**FileAccess.java )pS_+ZF  
*//文件访问(定位，写) V^ fGRA  
package NetFox; < R|)5/9  
import java.io.*; 7zg)h  
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public class FileAccessI implements Serializable{ _ 7BF+*T  
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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 6>=-/)p}  
RandomAccessFile oSavedFile; $ o5V$N D  
long nPos; T^'*_*m  
 ?+ -/';  
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public FileAccessI() throws IOException
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{ T+K` ^xv_L  
this("",0); %;<k(5bhGJ  
} J\xz^%p  
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public FileAccessI(String sName,long nPos) throws IOException ^fE\S5P  
{ @jE d%W  
oSavedFile = new RandomAccessFile(sName,"rw"); } T/}0W]0  
this.nPos = nPos; (RDa,
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oSavedFile.seek(nPos); rysP)e  
} Som. qD  
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public synchronized int write(byte[] b,int nStart,int nLen) C`NBHRa>  
{ V4`:Vci Aw  
int n = -1; Ms:KM{T0  
try{
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oSavedFile.write(b,nStart,nLen); #JL&]Z+X6  
n = nLen; _'!N q  
} L876$  
catch(IOException e) $ ]W[y=  
{ LsJs Q h  
e.printStackTrace (); d`?U!?Si  
} tDC0-N&6S~  
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return n; =E [4H  
} $@[dm)M  
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} ZL4l (&"  
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/* 9tzoris[~  
**SiteInfoBean.java }zkL[qu;  
*/ c!\.[2n  
package NetFox; iUeV5c
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public class SiteInfoBean { MB
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private String sSiteURL; //Site's URL n9]IBIthe  
private String sFilePath; //Saved File's Path <O
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private String sFileName; //Saved File's Name 6Gs{nFw  
private int nSplitter; //Count of Splited Downloading File ]regi- LGU  
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public SiteInfoBean() $R A4U<  
{//nSplitter的缺省值为5 tt+>8rxF:;  
//default value of nSplitter is 5 .abyYVrN4?  
this("","","",5); cr76cYq"Q  
} dV5P
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) d{QMST2&  
{ &_"ORqn&  
sSiteURL= sURL; SX1X<9  
sFilePath = sPath; o2
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sFileName = sName; \p5|}<Sr)  
this.nSplitter = nSpiltter; zb"rMzCH  
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! 9d_Gf-  
} #d7N| 9_  
!OPSSP]-  
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public String getSSiteURL() J+{Ou rWt  
{ 8K|J:[7  
return sSiteURL; lbQ6 a  
} AI&qU/}  
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public void setSSiteURL(String value)
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{ f'1(y\_fb  
sSiteURL = value; c*N50%=4  
} Iq)(UfaSve  
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public String getSFilePath() mbF(tSy  
{ ;c1relR2  
return sFilePath; L<bYRGz  
} J"diFz+20  
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9GO}&7   
public void setSFilePath(String value)
'#O;mBPNi  
{ bAdiA2VF'  
sFilePath = value; j3 6,w[Y:  
}  ci`zR9Ks  
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public String getSFileName() Rb)|66&3&  
{ 2$M,*Dnr  
return sFileName; g.9L)
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} As0 B\  
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public void setSFileName(String value) F;#zN  
{ haCKv   
sFileName = value; cI2Fpf`2Wj  
} ovo/!YJ2  
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public int getNSplitter() B1E$v(P3M  
{ '0Lov]L  
return nSplitter; nt=x]wEC  
} P^"R4T  
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public void setNSplitter(int nCount) jk )Vb  
{ 3S5^`Ag#  
nSplitter = nCount; tmp6hB  
} _l<mu?"  
} y=w`w>%  
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{J2#eiF  
/* Zb."*zL  
**Utility.java U2bzUxK  
*/ .l
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package NetFox; _lXt8}:+  
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public class Utility { w#&z]O9r  
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public Utility() b vRB  
{ gY!N3 *:  
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} s O=4IBE  
)|pU.K9qZ  
//线程睡眠 l xe`u}[  
public static void sleep(int nSecond) 09d9S`cS\  
{ T6uMFD4 |  
try{ pA.._8(t  
Thread.sleep(nSecond); qp>N^)>
 
} -(9O6)Rs$  
catch(Exception e) 7Lg7ei2mN7  
{ }Gr&w-v  
e.printStackTrace (); d`Oe_<  
} xI
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} ;'}'5nO=$  
!"E-\cc'  
//日志 (9]6bd  
public static void log(String sMsg) zT7"VbP  
{ (~&w-w3  
System.err.println(sMsg); BqB|Fo  
} Ns<?b;aK  
q jz3<`7-  
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public static void log(int sMsg) =We2^W-{
 
{ hm\\'_u  
System.err.println(sMsg); u]E.iXp  
} t`YWwI.  
} 1HbFtU`y~  
u]M\3V.  
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/*  WK==j1  
**TestMethod.java &yU>2=/T  
*/ IP ,.+:i  
package NetFox; <7'&1=%r  
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xQU"A2{}>  
public class TestMethod { 3z3_7XI  
c<4F4k7  
 ?Vc0)  
public TestMethod() VI_+v[Hk/  
{ ///xx/weblogic60b2_win.exe ] 8Tzr  
try{ b7Oj<!Wo`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); jj,r <T  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l5k?De_(x  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ORBxD"J&  
fileFetch.start(); : @6mFTV  
} ,h&a9:+i  
catch(Exception e){e.printStackTrace ();} ?:igumeYX  
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} ar$*a>'?  
?pG/m%[  
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public static void main(String[] args) .'T40=7  
{ {kL&Rv%'  
new TestMethod(); {eQWO
.C{  
} GeV+/^u  
} .z-UOyer  
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