http断点续传简单实现（java)

/* 2ntL7F<ow  
**SiteFileFetch.java b:SjJA,HM  
*/ nd
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package NetFox; w9G (^jS6  
import java.io.*; pxDkf|*  
import java.net.*; Et}S*!IS  
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public class SiteFileFetch extends Thread { [RoOc)u  
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SiteInfoBean siteInfoBean = null; //文件信息Bean & =)HPzC  
long[] nStartPos; //开始位置 OWx-I\:  
long[] nEndPos; //结束位置 j]Kpwf<NS  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 3MH9%*w'0  
long nFileLength; //文件长度 Zi/tax9C  
boolean bFirst = true; //是否第一次取文件 u$O` \=  
boolean bStop = false; //停止标志 *c3(,Bmw  
File tmpFile; //文件下载的临时信息 ark~#<SqAr  
DataOutputStream output; //输出到文件的输出流 #rD0`[pz  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） m&a.i B  
public SiteFileFetch(SiteInfoBean bean) throws IOException W US[hx,  
{ H|JPqBNRh  
siteInfoBean = bean; Jz
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 98'/yZ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g0O~5.f  
if(tmpFile.exists ()) B]iPixA6  
{ piULIZ0  
bFirst = false; 0n<>X&X
 
read_nPos(); E^qJ5pr_P  
} _3~/Z{z8  
else W|'7)ph  
{ @G,pM: t  
nStartPos = new long[bean.getNSplitter()]; ^hiIMqY_{`  
nEndPos = new long[bean.getNSplitter()]; D~P3~^  
} hg4d]R,  
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} C.4r`F$p  
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public void run()
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{ >8M=REn4  
//获得文件长度 [ICFPY6  
//分割文件 S#Q0aGj  
//实例FileSplitterFetch VW&EdrR,S  
//启动FileSplitterFetch线程 )cP&c=  
//等待子线程返回 JPO'1D)  
try{ .Q!_.LX  
if(bFirst) M$YU_RPl+  
{ Zaime  
nFileLength = getFileSize(); H?oBax:  
if(nFileLength == -1) B!+rO~  
{ ad)jw:n  
System.err.println("File Length is not known!"); )SU\s+"M  
} hQ7-m.UZw  
else if(nFileLength == -2) fVJlA  
{ 4|U$ON?x  
System.err.println("File is not access!"); O"^3,-  
}
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else Y=83r]%
 
{  3-~*  
for(int i=0;i<nStartPos.length;i++) R5Pk>-KF  
{  m#K)
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); Z=Z
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} pmwVVUEQ  
for(int i=0;i<nEndPos.length-1;i++) =-bGH   
{ 5}C.^J`  
nEndPos = nStartPos[i+1]; qTZ\;[CrP"  
} amTeTo]Tg  
nEndPos[nEndPos.length-1] = nFileLength; ml,FBBGq|-  
} u}r>?/V!  
} ]y0bgKTK  
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//启动子线程 \<ko)I#%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; p~'iK4[&6  
for(int i=0;i<nStartPos.length;i++) >V%lA3  
{ ~ECIL7,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =e)t,YVm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), pq"Z,9,F%  
nStartPos,nEndPos,i); *c<6 Er>s  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zsM2R"[X  
fileSplitterFetch.start(); ^ YOCHXg  
} PfR|\{(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v*";A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;NMv>1fI  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !MX
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nEndPos = " + nFileLength); jFDVd;#CS  
// fileSplitterFetch[nPos.length-1].start(); D~ogq]  
mO=A50_&,Q  
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//等待子线程结束 m>{a<N  
//int count = 0; s5/u>d  
//是否结束while循环 NiH =T  
boolean breakWhile = false; ~] &yHzp2  
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while(!bStop) x{O) n  
{ K/iFB  
write_nPos(); : E`78  
Utility.sleep(500); n1U!od  
breakWhile = true; \wV^uS  
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for(int i=0;i<nStartPos.length;i++) 
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{ [I?[N.v  
if(!fileSplitterFetch.bDownOver) G! Y l0Zr  
{ 9])Id;+91  
breakWhile = false; ,<=gPs;x  
break; )2lB  
} r.q*S4IS.m  
} Qz"+M+~%&  
if(breakWhile) W:maE9E=  
break; ^sKdN-{  
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//count++; "XQ3mi`y  
//if(count>4) =Vm3f^  
// siteStop(); 5e3p9K`5  
} gvFJ~lL  
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System.err.println("文件下载结束！"); wz..  
} o|$r;<o3R  
catch(Exception e){e.printStackTrace ();} RNF%i~nhO  
} &S=Qu?H  
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//获得文件长度 |<Y~\|  
public long getFileSize() p/yz`m T'w  
{ w@"Zjbs`  
int nFileLength = -1; /Y=_EOS  
try{ s3Wjhw/  
URL url = new URL(siteInfoBean.getSSiteURL()); QQ`tSYgex  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m@Dra2Cv'@  
httpConnection.setRequestProperty("User-Agent","NetFox"); o~<jayqU  
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int responseCode=httpConnection.getResponseCode(); <.#jp([W>  
if(responseCode>=400) \gu8 ~zK  
{ H:EK&$sU  
processErrorCode(responseCode); w&@zJ[  
return -2; //-2 represent access is error xM=ydRu  
} 6oa>\PDy   
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String sHeader; #zv&h`gY  
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for(int i=1;;i++) Q;N)$Xx  
{
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h<V,0sZ&:  
//Utility.log(in.readLine()); o|u4C{j  
sHeader=httpConnection.getHeaderFieldKey(i); IL:[0q  
if(sHeader!=null) 7;c^*"Ud  
{ d~MY z6"  
if(sHeader.equals("Content-Length")) |"PS e~ u  
{ GSs?!BIC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); q:nUn?zB  
break; 3ZC@q #R A  
} ,Ne9x\F  
} ALn_ifNh  
else !rs }83w!  
break; q %j8Js  
} {Q
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} 9B![l=Gh  
catch(IOException e){e.printStackTrace ();} ZeY|JH1  
catch(Exception e){e.printStackTrace ();} M3elog:M  
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Utility.log(nFileLength); kL8E#  
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return nFileLength; EXF]y}n  
} _xH<R  
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//保存下载信息（文件指针位置） [m4M#Lg\0  
private void write_nPos() Ie K+  
{ e$teh` p3  
try{ DE7y\oO]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); AOkG.u-k  
output.writeInt(nStartPos.length); U'msHF  
for(int i=0;i<nStartPos.length;i++) T{2)d]Y  
{ :ssj7wl :  
// output.writeLong(nPos); W
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output.writeLong(fileSplitterFetch.nStartPos); #6 ni~d&0  
output.writeLong(fileSplitterFetch.nEndPos); g_n_Qlo  
} J5{  
output.close(); 8KN3|)  
} QgKR=GR6  
catch(IOException e){e.printStackTrace ();} (&
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catch(Exception e){e.printStackTrace ();} *DvX||`&  
} g-jg;Ri  
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//读取保存的下载信息（文件指针位置） $&qLrKJ  
private void read_nPos() B|V!=r1%  
{ r\#nBoo(  
try{ 6&5D4 V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jz HWs  
int nCount = input.readInt(); e`U 6JzC  
nStartPos = new long[nCount]; yY!)2{F+  
nEndPos = new long[nCount]; %I9f_5BlT8  
for(int i=0;i<nStartPos.length;i++)  zR'EQ  
{ 0'THL%lK  
nStartPos = input.readLong(); T`pD
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nEndPos = input.readLong(); `&.qHw)  
} ?-%(K^y4r  
input.close(); [E%g3>/mt  
} .I EHjy\+  
catch(IOException e){e.printStackTrace ();} z.\r7  
catch(Exception e){e.printStackTrace ();}
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} glc<(V  
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private void processErrorCode(int nErrorCode) JWaWOk(t=?  
{ '^C *%"I]  
System.err.println("Error Code : " + nErrorCode);  Q
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} mR1b.$  
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//停止文件下载 livKiX`  
public void siteStop() (J.Z+s$:2  
{ pZK 1G  
bStop = true; L1I1SFG  
for(int i=0;i<nStartPos.length;i++) D vvi)/<  
fileSplitterFetch.splitterStop(); 4X*U~}  
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} XN6$TNsD$  
} 1<Mb@t  
//负责部分文件的抓取 xo?'L&%  
**FileSplitterFetch.java V=5S=7 Z:  
*/ /;w(sU  
package NetFox; %o4v} mzV  
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import java.io.*; Hc@_@G  
import java.net.*; - AgD  
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public class FileSplitterFetch extends Thread { -BI!ZsC'  
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String sURL; //File URL P7zUf  
long nStartPos; //File Snippet Start Position 6M`gy|"(~  
long nEndPos; //File Snippet End Position rv(N0p/  
int nThreadID; //Thread's ID jIr\.i  
boolean bDownOver = false; //Downing is over Q0Do B  
boolean bStop = false; //Stop identical 3) d}3w {  
FileAccessI fileAccessI = null; //File Access interface N?-ZvE\C  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException A?lR[`'u\  
{ 7FPSBvU#/  
this.sURL = sURL; 4)OOj14-V  
this.nStartPos = nStart; *P9"1K+  
this.nEndPos = nEnd; ,wM}h  
nThreadID = id; |a"]@W$>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?wl
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} yQ[;.<%v  
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public void run() *xpn-hCp<  
{ P*?|E@;s`  
while(nStartPos < nEndPos && !bStop) WA1d8nl  
{ spm)X-[1  
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try{ `Mt|+iT$p  
URL url = new URL(sURL); B+~ /-3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #9r}Kr=P  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2)}*'_
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String sProperty = "bytes="+nStartPos+"-"; 8<T~AU8'*  
httpConnection.setRequestProperty("RANGE",sProperty); u&c%L0)E&  
Utility.log(sProperty); &n_f.oUc  
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InputStream input = httpConnection.getInputStream(); [jlum>K  
//logResponseHead(httpConnection); %X.g+uu  
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byte[] b = new byte[1024]; bo90;7EK8  
int nRead; #_S]\=N(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2[3t7C  
{ >itabG-&  
nStartPos += fileAccessI.write(b,0,nRead); ps:`rVQ7  
//if(nThreadID == 1) 'R'hRMD9o  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,
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} cf$ hIB)Oi  
/3rNX}tOMH  

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Utility.log("Thread " + nThreadID + " is over!"); 5yK#;!:h  
bDownOver = true; >KP,67  
//nPos = fileAccessI.write (b,0,nRead); x=xo9wEg  
} o!~XYEXvUa  
catch(Exception e){e.printStackTrace ();} '"\n,3h  
} tbR  
} ^78N25RU(  
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//打印回应的头信息 4FZR }e\  
public void logResponseHead(HttpURLConnection con) Q>+rjN;  
{ k'|
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for(int i=1;;i++) <_t]?XHB[  
{ PDw+Q  
String header=con.getHeaderFieldKey(i); k Qr  
if(header!=null) c CDT27@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |5dNJF8;Q  
Utility.log(header+" : "+con.getHeaderField(header)); 6Y\TVRR  
else @{fwM;me]P  
break; #[x*0K-h  
} 0{B<A^Bf  
} G8__6v~  
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public void splitterStop() 7bO>[RQB  
{ gI2'[OU  
bStop = true; yv]|Ce@8A  
} wE=I3E%  
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} M\k[?i  
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/* fg
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**FileAccess.java /0gr?I1wr7  
*//文件访问(定位，写) 2bw), W  
package NetFox; xSM1b5=Pu  
import java.io.*; nj;3U^  
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public class FileAccessI implements Serializable{ W$,/hB& z  
{.e+?V2>_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 '/\*l<  
RandomAccessFile oSavedFile; c u";rnj  
long nPos; 2 yANf  
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public FileAccessI() throws IOException /({oN1X>i  
{ r_Ou\|jU  
this("",0); 4OJD_  
} J!~kqNI  
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public FileAccessI(String sName,long nPos) throws IOException J%r:"Jm[y1  
{ (2Lmu[  
oSavedFile = new RandomAccessFile(sName,"rw"); 3o>JJJ=]  
this.nPos = nPos;
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oSavedFile.seek(nPos); ;P juO  
} -eh .Tk  
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public synchronized int write(byte[] b,int nStart,int nLen) ]ke9ipj]:  
{ /8l@n
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int n = -1; ST[TKL<]  
try{ S!$S'{f<  
oSavedFile.write(b,nStart,nLen); y5aPs z  
n = nLen; (j@c946z""  
} Z+6WG  
catch(IOException e) 5HHf3E [  
{ (=WYi~2v  
e.printStackTrace (); F|m &n&  
} YCb|eS^u  
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return n; McS]aJfrk  
} ZD|F"v.  
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} Gukvd6-g9b  
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/* L'KKU4zj  
**SiteInfoBean.java DOFW"SpE  
*/ i={4rZOD^  
package NetFox; ZDp^k{AN9a  
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public class SiteInfoBean { z<fd!g+^  
[
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private String sSiteURL; //Site's URL >iK LC  
private String sFilePath; //Saved File's Path 8Ara^Xh}q  
private String sFileName; //Saved File's Name pYAKA1F  
private int nSplitter; //Count of Splited Downloading File }m^^6h  
r9M3rj]  
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public SiteInfoBean() acUyz2x  
{//nSplitter的缺省值为5 "m6G;cv  
//default value of nSplitter is 5 - uO(qUa#  
this("","","",5); *6AqRE  
} L..  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) G;wh).jG5  
{ )OFN
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sSiteURL= sURL; #tsP  
sFilePath = sPath; w;Fy/XQ  
sFileName = sName; _!,2"dS  
this.nSplitter = nSpiltter; XHKLl?-  
V"K.s2U^  
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} |unvDXx-  
,/V~T<FI  
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public String getSSiteURL() adri02C/  
{ H<ovIMd  
return sSiteURL; IaRwPDj6  
} F|!=]A<  
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public void setSSiteURL(String value) ALO/{:l(  
{ _D{FQRU<YD  
sSiteURL = value; t(PA+~sIp  
} `.pd %\  
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public String getSFilePath() d { P$}b  
{ {0fQ
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return sFilePath; iI'ib-d  
} vNd
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public void setSFilePath(String value) G[>CBh5  
{ (yuOY/~k/  
sFilePath = value; |cuKC \  
} @~7au9.V=X  
=
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public String getSFileName() v;?W|kJ.u  
{ uhaHY`w  
return sFileName; Ywt9^M|z;  
} n|Y}M]u,  
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? ][/hL@[  
public void setSFileName(String value) 8 ks\-38n1  
{ !~7lY]_U  
sFileName = value; #7:ah  
} "9hD4R  
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public int getNSplitter() ${ DSH  
{ k'e1ZAn  
return nSplitter; #^|2PFh5  
} 8~.8"gQ
 
|7Z}#eP//  
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public void setNSplitter(int nCount) !,b&e  
{ {A ,w%  
nSplitter = nCount; -cn`D2RP  
} {H9
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} xi,fm  
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2p 7;v7)y  
/* f`-vnh^+  
**Utility.java e iH
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*/ '< >Q20  
package NetFox; I'n}6D.M  
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public class Utility { E"/k"1@  
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public Utility() bng/v  
{ /=#~8  
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} 7NvRZ!  
|VyN>
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//线程睡眠 B'vIL'  
public static void sleep(int nSecond) 1Zo3
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{ U =g&c `  
try{ 0d~?|Nv -  
Thread.sleep(nSecond); /a-s9<  
} 3aU4Z|f~  
catch(Exception e) !T~uxeZ/;  
{ md\Vw?PkU  
e.printStackTrace (); D=5%lL  
} Gw6!cp|/  
} w'xPKO$bzR  
1guiuR4  
//日志 7g oRj  
public static void log(String sMsg) :Us+u-~  
{ SD:Bw0gzrI  
System.err.println(sMsg); .K#' Fec  
} 2Mw`  
fp3`O9+em  
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public static void log(int sMsg) EQHCw<e  
{ G-vkkNj%e  
System.err.println(sMsg); +^rt48${ y  
} (Nf!E[}Z  
} wYv++< z  
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/* sVnp
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**TestMethod.java Eh9{n,5-  
*/ l u{6  
package NetFox; Z{F^qwne  
3Dj>U*fP  
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public class TestMethod { cvtn,Ml6  
7s0y.i~  
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public TestMethod() 00Ye ]j_  
{ ///xx/weblogic60b2_win.exe 9r
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try{ a?W<<9]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {G|= pM\'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); H:16aaMn(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); J/Ch /Sa  
fileFetch.start(); \x8'K  
} HMKogGTTo  
catch(Exception e){e.printStackTrace ();} x IL]Y7HWM  
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} I "R<XX  
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!(j<Y0xo:  
public static void main(String[] args) =C^4nP-  
{ P}!pmg6V  
new TestMethod(); /(}YjeS  
} ^'b\OUty-  
} g- INhzMu  
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