http断点续传简单实现（java)

/* a$=BX=  
**SiteFileFetch.java
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*/ Uu_g_b:z  
package NetFox; 9Wu c1#  
import java.io.*; pyHU+B  
import java.net.*;  3o_)x  
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public class SiteFileFetch extends Thread { WdWMZh  
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SiteInfoBean siteInfoBean = null; //文件信息Bean )2z<5
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long[] nStartPos; //开始位置 $Cgl$A  
long[] nEndPos; //结束位置 wDQ@$T^vh  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #}PQ !gZ  
long nFileLength; //文件长度 8k( zU>^  
boolean bFirst = true; //是否第一次取文件 t4;eabZK  
boolean bStop = false; //停止标志 k kZ2Jxvx  
File tmpFile; //文件下载的临时信息 UWW^g@d4  
DataOutputStream output; //输出到文件的输出流 ='W=  
y ;/T.W9!  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 
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public SiteFileFetch(SiteInfoBean bean) throws IOException kC,=E9)O  
{ saRYd{%+  
siteInfoBean = bean; f 7R
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); r|MBkpc
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %fT%,( w}t  
if(tmpFile.exists ()) -R]Iu\  
{ vU,V[1^a  
bFirst = false; A "
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read_nPos(); @d&JtA  
}
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else ^l:~r2  
{ PFKl6_(  
nStartPos = new long[bean.getNSplitter()]; 8AjQPDn+  
nEndPos = new long[bean.getNSplitter()]; f]pHJVgFV  
} AX%N:)_$|  
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} r*
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public void run() /3`yaYkSh  
{ +Rj8"p$K  
//获得文件长度 ; Sd== *  
//分割文件 @~z4GTF9i  
//实例FileSplitterFetch uGmv`R_  
//启动FileSplitterFetch线程 c$.Zg=  
//等待子线程返回 ?v z[Zi  
try{ BS.5g<E2q  
if(bFirst) `<3%`4z/  
{ >]L
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nFileLength = getFileSize(); C3K":JB  
if(nFileLength == -1) !V'~<&   
{ ptc.JB6  
System.err.println("File Length is not known!"); } =
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} dfA2G<Uc  
else if(nFileLength == -2) :@RX}rKG  
{ 9bQD"%ha=d  
System.err.println("File is not access!"); {X\%7Zef+  
} aMJW__,  
else  erQQ_  
{ M=M~M$K  
for(int i=0;i<nStartPos.length;i++) ]Sey|/@D  
{ 4C#r=Uw`  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); eP|_  
} yMz dM&a!*  
for(int i=0;i<nEndPos.length-1;i++) 6Y%{ YQ}s|  
{ 2@6Qifxd@  
nEndPos = nStartPos[i+1]; Ueu~803~  
} N79?s)l:K  
nEndPos[nEndPos.length-1] = nFileLength; 3Q#
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} Ez/>3:;  
} i*]$_\yl"  
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//启动子线程 M?d(-en  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Ihd{tmr<  
for(int i=0;i<nStartPos.length;i++) o(gV;>I  
{ Gc=uKQ+\V  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o?g9Grk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), TFNB%|  
nStartPos,nEndPos,i);
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); kz"QS.${  
fileSplitterFetch.start(); h+!@`c>)Y  
} 2M>`W5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FfX*bqy
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); NI:3hfs  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", YO9ofT  
nEndPos = " + nFileLength); OJ1MV7&  
// fileSplitterFetch[nPos.length-1].start(); 9'=ZxV  
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//等待子线程结束 :'4",  
//int count = 0; >qU5(M_&L  
//是否结束while循环 }0C v J4  
boolean breakWhile = false; VBtdx`9  
=3Ohy,5L  
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while(!bStop) O9*l6^Scw  
{ =`k',V_  
write_nPos(); =p[a Cb i  
Utility.sleep(500); "
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breakWhile = true; z.~jqxA9  
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for(int i=0;i<nStartPos.length;i++) Eq=j+ch7  
{ gle<{ `  
if(!fileSplitterFetch.bDownOver) zGwM# -  
{ KRM:h`+-.-  
breakWhile = false; n#5S-z1KNw  
break; Os/?iGlD*E  
} n}dLfg*  
} R:`)*=rL%  
if(breakWhile) +xuj]J  
break; A!v:W6yiz  
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//count++; G+t=+T2m  
//if(count>4) MJA;P7g  
// siteStop(); XE8%t=V!c$  
} y7Nd3\v [\  
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System.err.println("文件下载结束！"); mgTzwE_\  
} c5Hyja=  
catch(Exception e){e.printStackTrace ();} TSH'OW !b  
} X.V4YmZ-;  
#fDM{f0]R  
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//获得文件长度 i}O.,iH  
public long getFileSize() G8.nKoHv7x  
{ G0he'BR  
int nFileLength = -1; d+nxvh?I8  
try{ c=D~hzN  
URL url = new URL(siteInfoBean.getSSiteURL()); I9<%fv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @V Sr'?7-  
httpConnection.setRequestProperty("User-Agent","NetFox"); :_h#A}8Xd  
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int responseCode=httpConnection.getResponseCode(); 4+Jf!ovS=  
if(responseCode>=400) 1/v#Z#3[  
{ ,hWuAu6.L  
processErrorCode(responseCode); rYM@e  
return -2; //-2 represent access is error dwouw*8  
} w3&L 6|,  
:m<#\!?  
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String sHeader; &YBZuq2?  
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for(int i=1;;i++) -56gg^Pnr  
{ DUwms"I,%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Os*s{2OvO  
//Utility.log(in.readLine()); qYQ vjp  
sHeader=httpConnection.getHeaderFieldKey(i); pq:[`  
if(sHeader!=null) F<^f6z8  
{ pwRCfR)"X  
if(sHeader.equals("Content-Length"))  7gx?LI_e  
{ (|pM^+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); k~?5mUyK<  
break; nG-DtG^z  
} 0]zMb^wo  
} +p$lVnAt  
else SX&Q5:  
break; F##xVmR~  
} L#S|2L_hC  
} CaVVlL  
catch(IOException e){e.printStackTrace ();} %LuA:{EVD  
catch(Exception e){e.printStackTrace ();} x.sC015Id  
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Utility.log(nFileLength); '>HLE)l  
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return nFileLength; P-DW@drxF  
} Tv9\`F[  
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//保存下载信息（文件指针位置） 5}b)W>3@`  
private void write_nPos() !3{;oU%*  
{ _M^^0kf  
try{  $Tal.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); j<k-w  
output.writeInt(nStartPos.length); [ P,gEYk  
for(int i=0;i<nStartPos.length;i++) y#
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{ FV{XPr%   
// output.writeLong(nPos); Y ` Z,52  
output.writeLong(fileSplitterFetch.nStartPos); 8T[<&<^-  
output.writeLong(fileSplitterFetch.nEndPos); Cu_-QE  
} n(i/jW~0w  
output.close(); rM? J40&.  
} v3G$9(NE;  
catch(IOException e){e.printStackTrace ();} UY .-Qt  
catch(Exception e){e.printStackTrace ();} bz1AmNZ
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} sY1.z5"Mm  
4_# (y^9  
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//读取保存的下载信息（文件指针位置） nTD4^'  
private void read_nPos() W0}FOfL9  
{ Rd<K.7&A}  
try{ >s )L(DHa"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); qC5IV}9`  
int nCount = input.readInt(); yF1p^>*ak&  
nStartPos = new long[nCount]; lBa` nG  
nEndPos = new long[nCount]; 'rq@9$h1W  
for(int i=0;i<nStartPos.length;i++) !,C8  
{ %m|1LI(  
nStartPos = input.readLong(); [Zzztn+  
nEndPos = input.readLong(); SM1L^M3)  
} QK
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input.close(); /,~g"y.;,  
} +N'&6z0Wf  
catch(IOException e){e.printStackTrace ();} Z:^ S-h  
catch(Exception e){e.printStackTrace ();} 2H`>Kj  
} KT17I&:  
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private void processErrorCode(int nErrorCode) :F9Oj1lM%  
{ VGc.yM)& j  
System.err.println("Error Code : " + nErrorCode); b
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} X
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//停止文件下载 m4yWhUi(o  
public void siteStop() KzJJ@D*4M]  
{ Q- w_@~  
bStop = true; /`0>U  
for(int i=0;i<nStartPos.length;i++) EB@rIvUi,  
fileSplitterFetch.splitterStop(); KT
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} "{trK?-8%  
} 18p4]:L  
//负责部分文件的抓取 Wc,`L$Jx  
**FileSplitterFetch.java :DeJnE  
*/ Ypxp4B  
package NetFox; =LgMG^@mu  
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import java.io.*; OJhMM-  
import java.net.*; ~)zxIO!  
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public class FileSplitterFetch extends Thread { '=eVem=  
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String sURL; //File URL URt+MTU[  
long nStartPos; //File Snippet Start Position VF b  
long nEndPos; //File Snippet End Position S]Di1E^r;_  
int nThreadID; //Thread's ID U3{4GmrT  
boolean bDownOver = false; //Downing is over _/u(:  
boolean bStop = false; //Stop identical [=tIgMmz  
FileAccessI fileAccessI = null; //File Access interface {[hgSVN;  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException mIPDF1=)  
{ {+[Ex2b$  
this.sURL = sURL; j(}pUV B  
this.nStartPos = nStart; WF_QhKW|k  
this.nEndPos = nEnd;  Mz+vT0  
nThreadID = id; )vpYVr-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 cd=K=P}p  
} rq Uk_|Xa  
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public void run() mNEh\4ai  
{ O%
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while(nStartPos < nEndPos && !bStop) u} +?'B)  
{ xE$lx:C"FU  
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try{ tOxH9  
URL url = new URL(sURL); d0&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FMhuCl2  
httpConnection.setRequestProperty("User-Agent","NetFox"); )heHERbJ  
String sProperty = "bytes="+nStartPos+"-"; ^FVmP d*1  
httpConnection.setRequestProperty("RANGE",sProperty); N2Ysi$  
Utility.log(sProperty); MJCz %zK  
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InputStream input = httpConnection.getInputStream(); `%EcQ}Nr  
//logResponseHead(httpConnection); *-uzsq.W  
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& JJ*?Dl  
byte[] b = new byte[1024]; _ n1:v~  
int nRead; D;jbZ9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) z.?slYe[  
{ #0\* 86  
nStartPos += fileAccessI.write(b,0,nRead); _OS,
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//if(nThreadID == 1) ^".6~{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Azp!;+  
} ULgp]IS  
{"2CI^!/U.  
)[r=(6?n  
Utility.log("Thread " + nThreadID + " is over!"); ~jmI`X/  
bDownOver = true; ckv8QAm  
//nPos = fileAccessI.write (b,0,nRead); [tElt4uG  
} ^4Ff8Y  
catch(Exception e){e.printStackTrace ();} x8~*+ j  
} k g Rys  
} OdNcuiLa  
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//打印回应的头信息 NV@$\<  
public void logResponseHead(HttpURLConnection con) m6]6!_  
{ %DA`.Z9#  
for(int i=1;;i++) 9sd}Z,l  
{ l4(FM}0X5}  
String header=con.getHeaderFieldKey(i); &-X51O C  
if(header!=null) 8xG"hJR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [Fv,`*/sm  
Utility.log(header+" : "+con.getHeaderField(header)); 8.7q -<Q  
else !^v~hD$_q  
break; z|Yt|W  
} Df:/r%  
} C5$?Y8B3  
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public void splitterStop() t5u#[*  
{ OdL/%Zp
}  
bStop = true; VeZd\Oe  
} *!{&n*N  
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} pjFj{  
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;Ru[^p.{  
/* Q&_#R(3j;  
**FileAccess.java >l/pwb@  
*//文件访问(定位，写) $b2~H+u(  
package NetFox; :XPat93w  
import java.io.*; \pTv;(  
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public class FileAccessI implements Serializable{  H{Lt,#  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [p}~M-$V8Y  
RandomAccessFile oSavedFile; e"XolM0IM  
long nPos; Wm5[+z|2?9  
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public FileAccessI() throws IOException m({q<&]Qp  
{ q;IuV&B  
this("",0); CdPQhv)m  
}
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public FileAccessI(String sName,long nPos) throws IOException ?~#[cx  
{ %g3QE:(2@q  
oSavedFile = new RandomAccessFile(sName,"rw"); ]KXyi;n2  
this.nPos = nPos; ~Fl\c-  
oSavedFile.seek(nPos); D/%v/m
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} ~ _tK.m3  
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public synchronized int write(byte[] b,int nStart,int nLen) 7!FiPH~kM  
{ TBba3%  
int n = -1; 5 wN)N~JE  
try{ PYY<
  
oSavedFile.write(b,nStart,nLen); !r/~D |  
n = nLen; G\,B*$3   
} h4MBw=Tz~  
catch(IOException e) 0Js5 ' 9}H  
{ rg]b$tL~  
e.printStackTrace (); @\xEK5SG  
} }1+2&Ps50  
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return n; XFl&(I4tB  
} :?m"kh ~  
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} 1&7?f  
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/* W[]|Uu/%  
**SiteInfoBean.java [fb9;,x`  
*/ O#C0~U]dDW  
package NetFox; .pm%qEh  
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9.( [,J  
public class SiteInfoBean { zcH"Kh&  
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private String sSiteURL; //Site's URL
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private String sFilePath; //Saved File's Path {)!ua7GF0H  
private String sFileName; //Saved File's Name 5nceOG8  
private int nSplitter; //Count of Splited Downloading File b E40^e  
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public SiteInfoBean()
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{//nSplitter的缺省值为5 I69Z'}+qz  
//default value of nSplitter is 5 /l3Oi@\  
this("","","",5); Gi$\th,  
} KZ^>_K&  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) D;+Y0B  
{ {Dy,|}7s  
sSiteURL= sURL; Az#kE.8b*A  
sFilePath = sPath; -;qK_x  
sFileName = sName; p-rQ'e  
this.nSplitter = nSpiltter; [
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} `022gHYv  
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#  
public String getSSiteURL() [)I W9E v  
{ FB
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return sSiteURL; d.B<1"MQ  
} '}(Fj2P79  
0R(['s:3`  
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public void setSSiteURL(String value) 9:Bn-3)  
{ n:s _2h(u  
sSiteURL = value; mc@Z+t'  
} EUH9R8)  
w Bm4~~_  
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public String getSFilePath() X(DP=C}v9  
{ "@5{=  
return sFilePath; 4mX]JH`UTe  
} L5 Ai  
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public void setSFilePath(String value) ^%g8OP  
{ r(wtuD23q  
sFilePath = value; Zc&pJP+M'U  
} |gINB3L  
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public String getSFileName() ?hIDyM  
{ s`.J!^u`  
return sFileName; 5N;xo??  
} WU
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public void setSFileName(String value) >!o!rs  
{ Nr]guC?rE  
sFileName = value; +x4*T  
} 4ISIg\:c*  
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I!K-* AB  
public int getNSplitter() o4z|XhLr  
{ uz=9L<$  
return nSplitter; HoWK#Nz\  
} `G*fx=N  
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public void setNSplitter(int nCount) b#t5Dve  
{ X
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nSplitter = nCount; NPa4I7`A  
} U56g|V  
} Eb29tq  
v6=X]Ji{YA  
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/* rploQF~OFF  
**Utility.java S'@Ok=FSy  
*/ 20J-VN:  
package NetFox; G1ruF8  
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{ W5 _KX  
public class Utility { R7FI{A  
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public Utility() mOL
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{ =~)rT8+)  
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} rO/Sj<0^  
b!"FM/%  
//线程睡眠 U2Ky4UFm  
public static void sleep(int nSecond) %y)hYLOJ  
{ i.-2 w6  
try{ CWd &  
Thread.sleep(nSecond); O%&N6U  
} $"0`2C  
catch(Exception e) 'S#^70kt  
{ n2[h`zm1{B  
e.printStackTrace (); c<Q*g  
} 7c@5tCcC-  
} :kjs: 6f]  
e\*(F3r  
//日志 '?X?'_3  
public static void log(String sMsg) >+:cTQ|q  
{ u:w
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System.err.println(sMsg); xKepZ  
} 4"^W/Zo  
X@)'E9g5:  
~1
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public static void log(int sMsg) F hyY+{%  
{ p}X *HJq$  
System.err.println(sMsg); 5,Co(K  
} jz\>VYi(7  
} 6hXh;-U  
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{e., $'#  
/* `sd H q  
**TestMethod.java V*@&<x"E  
*/ ZHj7^y@P  
package NetFox; @TzUcE  
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public class TestMethod { B.gEV*@  
.n?i'8  
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public TestMethod() 8CvNcO;H0  
{ ///xx/weblogic60b2_win.exe m/,8\+  
try{
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); A43[i@o  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *WWDwY@!u  
SiteFileFetch fileFetch = new SiteFileFetch(bean); JX{rum  
fileFetch.start(); 0 r;tI"  
} 2B_+5  
catch(Exception e){e.printStackTrace ();} }me`(zp  
z`]:\j'O3"  
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} Ov.oy
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pp >F)A0v  
public static void main(String[] args) <LX-},?P  
{ d%p{l)Hd  
new TestMethod(); Y"m}=\4{  
} $:v
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} R+Ug;r-[  
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