http断点续传简单实现（java)

/* }Y:V&4DW  
**SiteFileFetch.java k..AP<hH  
*/ E%LUJx}  
package NetFox; Qco8m4n  
import java.io.*; VYbH:4K@%  
import java.net.*; k'QI`@l&l  
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public class SiteFileFetch extends Thread { !y+uQ_IS@  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 2ca#@??R  
long[] nStartPos; //开始位置 ~[<C6{  
long[] nEndPos; //结束位置 C cPOK2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 |P@N}P@  
long nFileLength; //文件长度 G>=Fdt7Oc  
boolean bFirst = true; //是否第一次取文件 :CLWmMC_  
boolean bStop = false; //停止标志 .J<t]  
File tmpFile; //文件下载的临时信息 hi`[  
DataOutputStream output; //输出到文件的输出流 =WT&unw}
 
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1oe,>\\  
public SiteFileFetch(SiteInfoBean bean) throws IOException [;H-HpBaa  
{ 4M#i_.`z  
siteInfoBean = bean; pT{is.RM  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }ZK%
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |sdG<+  
if(tmpFile.exists ()) 47N,jVt4  
{ Z_[ P7P  
bFirst = false; ;4l8Qg 7  
read_nPos(); ; [G:  
} DQ(0:r  
else p#).;\M   
{ R2v9gz;W  
nStartPos = new long[bean.getNSplitter()]; A 0v=7 ]  
nEndPos = new long[bean.getNSplitter()]; 8OKG@hc  
} FRuPv6  
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} 3_<l`6^Ns/  
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public void run() MA,*$BgZ  
{ U$mDAi$  
//获得文件长度 [I=|"Ic~  
//分割文件 {
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//实例FileSplitterFetch aX`uF<c9  
//启动FileSplitterFetch线程 eT+i&  
//等待子线程返回 5mQ@&E~#W  
try{ WW+xU0  
if(bFirst) gu3i
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{ vP x/&x  
nFileLength = getFileSize(); K(i}?9WD  
if(nFileLength == -1) K fD.J)  
{ VxBBZsZO~  
System.err.println("File Length is not known!"); @QV0l]H0+  
} arDl2T,igF  
else if(nFileLength == -2) g]lEG>y1R  
{ Bhxs(NO  
System.err.println("File is not access!"); n74\{`8]o  
} ZA+dtEE=f9  
else ka~_iUU4  
{ 9T;4aP>6j#  
for(int i=0;i<nStartPos.length;i++) #h?IoB7  
{ tsAV46S  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |]4!W
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} ao2^3e  
for(int i=0;i<nEndPos.length-1;i++) _;BwP  
{ eJ99W=  
nEndPos = nStartPos[i+1]; Q]YB.n3  
} l::q F 0  
nEndPos[nEndPos.length-1] = nFileLength; g3z/yj  
} )GkJ%o#H2  
} g%&E~V/g$  
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^1najUpQ_n  
//启动子线程 GHsDZ(d3.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; JWNN5#=fQ  
for(int i=0;i<nStartPos.length;i++) %Psg53N  
{ L1SX2F8
  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }F>RIjj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Ca~8cQ  
nStartPos,nEndPos,i); *j3U+HV  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o<nM-"yWb  
fileSplitterFetch.start(); A[l )>:  
} Ti? "Hr<W  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %r^tZ;;l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9K$ x2U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;P
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nEndPos = " + nFileLength); bW
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// fileSplitterFetch[nPos.length-1].start(); /nO_e  
{,Z|8@Sl%  
1
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//等待子线程结束 x// uF  
//int count = 0; jRsl/dmy  
//是否结束while循环 !j$cBf4  
boolean breakWhile = false; >#h,q|B  
;` L%^WZ;-  
/`m*PgJ  
while(!bStop) hJSvx  
{ pLu5x<  
write_nPos(); |eRE'Wd0  
Utility.sleep(500); `+Nv=vk  
breakWhile = true; : ;8L1'  
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for(int i=0;i<nStartPos.length;i++) P].Eb7I  
{ s17)zi,?4  
if(!fileSplitterFetch.bDownOver) Tv#d>ZSD  
{ q]1p Q)\'p  
breakWhile = false; (.$e@k=  
break; ~^g*cA t}  
} /XuOv(j  
} }%,LV]rGEZ  
if(breakWhile) 5*y6{7FLp  
break; > mP([]  
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//count++; :-+j,G9t  
//if(count>4)
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// siteStop(); '^:q|h  
} 3+vMi[YO  
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System.err.println("文件下载结束！"); #4& <d.aw'  
} R+=Xr<`%U|  
catch(Exception e){e.printStackTrace ();} *nY$YwHB  
} vPu{xy  
4+N9Ylh  
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//获得文件长度 ,Mu"r!MK  
public long getFileSize() <d3a  
{ K=J">^uW  
int nFileLength = -1; g+ cH  
try{ h]
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URL url = new URL(siteInfoBean.getSSiteURL()); %Q5 |RLD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S\A9r!
2  
httpConnection.setRequestProperty("User-Agent","NetFox"); J/A UOInh  
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int responseCode=httpConnection.getResponseCode(); NKu*kL}W=  
if(responseCode>=400) l]geQl:7`r  
{ pIvr*UzY  
processErrorCode(responseCode); .:TSdusr~  
return -2; //-2 represent access is error ;-{'d8  
} }H9V$~}@-  

!;&{Q^}  
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String sHeader; qoJ<e`h}
 
,) 3Eog\-  
/8s>JPXKH[  
for(int i=1;;i++) '<hgc  
{ Q+^"v]V`d  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .OvH<%g!.  
//Utility.log(in.readLine()); 2[Bw+<YA`  
sHeader=httpConnection.getHeaderFieldKey(i); ]*yUb-xY  
if(sHeader!=null) hkvymHaG  
{ rPoq~p
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if(sHeader.equals("Content-Length")) uBxs`'C  
{ Zl=IZ?F   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); N/
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break; C3e0d~C  
} 0D^c4[Y'l  
} JReJlDu  
else 6^hCW`jG  
break; 5?C) v}w+  
} =
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} iKe68kx  
catch(IOException e){e.printStackTrace ();} bRK[u\,  
catch(Exception e){e.printStackTrace ();} sWX\/Iyy2p  
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s%S; 9T  
Utility.log(nFileLength); 3v:c'R0  
)+12r6W  
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return nFileLength; CC{{@  
} ,L9ioYbp  
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//保存下载信息（文件指针位置） ~<Sb:Izld  
private void write_nPos() \tZZn~ex  
{ xBKis\b  
try{ k5]`:k6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); R}Z2rbt  
output.writeInt(nStartPos.length); B>,&{ah/5J  
for(int i=0;i<nStartPos.length;i++) b;Uqyc  
{ W>(p4m  
// output.writeLong(nPos); Pvu*Y0_p  
output.writeLong(fileSplitterFetch.nStartPos); t{Xf3.  
output.writeLong(fileSplitterFetch.nEndPos); )NL_)
)\  
} FW--|X]8  
output.close();
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} |sklY0?l(  
catch(IOException e){e.printStackTrace ();} e95@4f^K2  
catch(Exception e){e.printStackTrace ();} !_#2$J*s^D  
} <c$K3  
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//读取保存的下载信息（文件指针位置） 0z:BSdno  
private void read_nPos() T9=55tpG9  
{ v'H\KR-;  
try{ ;Alw`'  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _vgFcE~E@  
int nCount = input.readInt(); i*-L_!cc:  
nStartPos = new long[nCount]; 47 *,  
nEndPos = new long[nCount]; >xJh!w<
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for(int i=0;i<nStartPos.length;i++) >,s.!
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{ AEr8^6  
nStartPos = input.readLong(); f+iM_MI  
nEndPos = input.readLong(); [W{WfJ-HwG  
} _k2*2db   
input.close(); huw|J<$  
} pz]#/Ry?  
catch(IOException e){e.printStackTrace ();} v<c@bDZ>  
catch(Exception e){e.printStackTrace ();} -^+!:0'
;  
} )`B n"=  
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private void processErrorCode(int nErrorCode) ~i ImM|*0  
{ \
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System.err.println("Error Code : " + nErrorCode); GN%|'eU  
} NHjZ`=Js  
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//停止文件下载 zPKx: I3  
public void siteStop() H6I]GcZ$  
{ mqFo`Ee  
bStop = true; lE@ V>%b  
for(int i=0;i<nStartPos.length;i++) rbw5.NU  
fileSplitterFetch.splitterStop(); =Pu;wx9  
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} 2y0J~P!I  
} ,|r%tNh<8$  
//负责部分文件的抓取  l,n V*Z  
**FileSplitterFetch.java Z+G.v=2q<  
*/ VX<jg#(  
package NetFox; NEb M>1>^  
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import java.io.*; c4'k-\JvT  
import java.net.*; CC<(V{Png  
6|-V{  
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public class FileSplitterFetch extends Thread { <HC5YA)4  
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1  
String sURL; //File URL sD!)=t_  
long nStartPos; //File Snippet Start Position 7|/Ct
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long nEndPos; //File Snippet End Position vTdJe  
int nThreadID; //Thread's ID -xXz}2S4  
boolean bDownOver = false; //Downing is over 1YrIcovi-  
boolean bStop = false; //Stop identical K#e&yY  
FileAccessI fileAccessI = null; //File Access interface ls928  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,@#))2<RK  
{ $k,wA8OZ-  
this.sURL = sURL; |*T3TsP u  
this.nStartPos = nStart; 1ab_^P  
this.nEndPos = nEnd; 1#D&cx6  
nThreadID = id; {|E'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 fQkfU;5  
} 26&$vgO~:  
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public void run() K|{IX^3)V  
{ 6Bop8B  
while(nStartPos < nEndPos && !bStop) a4[t3U  
{ edo+ o{^  
8iTB  
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try{ H:)_;k  
URL url = new URL(sURL); $J):yhFs e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }K5okxio  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z9.0#Jnu  
String sProperty = "bytes="+nStartPos+"-"; +n<W#O%  
httpConnection.setRequestProperty("RANGE",sProperty); shR|  
Utility.log(sProperty); %!r.)Wx|2  
 wX5q=I  
58d[>0Xa[g  
InputStream input = httpConnection.getInputStream(); 3@qv[yOE  
//logResponseHead(httpConnection); F}7sb#G  
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byte[] b = new byte[1024]; ALy7D*Z]w  
int nRead; c-PZG|<C[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ``P9f
d  
{ 4g"%?xN  
nStartPos += fileAccessI.write(b,0,nRead); J jm={+@+  
//if(nThreadID == 1) _U}vKm  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hPUAm6b;  
} BvsSrse  
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Utility.log("Thread " + nThreadID + " is over!"); MqB
@}!  
bDownOver = true; *g,ls(r\[
 
//nPos = fileAccessI.write (b,0,nRead); rVqQo`K\  
} jLVG=rO
n  
catch(Exception e){e.printStackTrace ();} |$b8(g$s)  
} 0cE9O9kE  
} QM#Vl19>j(  
c)LG+K  
mmbe.$73  
//打印回应的头信息 jwT` Z  
public void logResponseHead(HttpURLConnection con) \1jThJn  
{ Yu\$Y0 {]  
for(int i=1;;i++) }q`9U!v  
{ s`_EkFw>Gl  
String header=con.getHeaderFieldKey(i); aL4^ po  
if(header!=null) $j.;$~F  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ["<Xh0_  
Utility.log(header+" : "+con.getHeaderField(header)); o 2Nu@^+  
else Tc/^h4xH  
break; b^Z2Vf:k]  
} !:!(=(4
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} 6X*vCylI  
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h(HpeN%`#  
public void splitterStop() } +}nrJv  
{ OUi;f_
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bStop = true; |y U!d %  
} P|<V0 Vs.  
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} Xx{| [2`  
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{P8d^=#q  
/* 3p=Xv%xd  
**FileAccess.java ]ub"OsXC  
*//文件访问(定位，写) %=UD~5!G0  
package NetFox; N.
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import java.io.*; H54RA6$>  
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r >'tE7W9  
public class FileAccessI implements Serializable{ FMVAXOO  
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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 Mp`$1Ksn  
RandomAccessFile oSavedFile; 2R&\qZ<  
long nPos; ~.W]x~X$  
fp [gKRSF  
bT,_=7F  
public FileAccessI() throws IOException 2o SM|  
{ &D<R;>iI  
this("",0); 1wR[nBg*|  
} I\mF dE  
+hN>Q$E  
83vMj$P  
public FileAccessI(String sName,long nPos) throws IOException RIMSXue*Ha  
{ :c/54Ss~  
oSavedFile = new RandomAccessFile(sName,"rw"); 3]*Kz*i  
this.nPos = nPos; p\&O;48=   
oSavedFile.seek(nPos); &e^;;<*w  
} m]n2wmE3n  
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Fl`U{03  
public synchronized int write(byte[] b,int nStart,int nLen) 1B;2 ~2X  
{ ]hS:0QE  
int n = -1; =.3#l@E!C  
try{ r!Eh}0bL  
oSavedFile.write(b,nStart,nLen); uPfz'|,  
n = nLen; h&'|^;FM  
} EZ<:>V-_D  
catch(IOException e) CTNL->  
{ 0+CcNY9  
e.printStackTrace (); e0P[,e*0  
} EVPQe-  
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return n; !yd B,S  
} vfkF@^D  
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} lUu0AZQmG  
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/* M%13b$i~f  
**SiteInfoBean.java ;Uypv|xX  
*/ &x.5TDB>%  
package NetFox; gf;B&MM6  
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public class SiteInfoBean { lR ZuXo9<  
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private String sSiteURL; //Site's URL FYa
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private String sFilePath; //Saved File's Path utdus:B#0  
private String sFileName; //Saved File's Name CTB qX  
private int nSplitter; //Count of Splited Downloading File (Kkqyrb  
od/Q"5t[p  
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public SiteInfoBean() 2G/CN"  
{//nSplitter的缺省值为5 meD?<g4n~"  
//default value of nSplitter is 5 X5)].[d  
this("","","",5); C%P"\>5@  
} =6,w~|W  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) I(Q3YDdb  
{ 2,6|l.WFpE  
sSiteURL= sURL; H1ox>sC  
sFilePath = sPath; O=}jg0k  
sFileName = sName; Kb#
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this.nSplitter = nSpiltter; mk`#\=GE  
;0 9~#Wop  
|s[k= /~"  
} w;DRC5V>  
":Ll.=!  
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public String getSSiteURL() /c52w"WW  
{ _*dUH5  
return sSiteURL; #s]`jdc  
} +m1y#|08  
%D
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Jbqm?Fy4X  
public void setSSiteURL(String value) =bl6:  
{ |7E1yu  
sSiteURL = value; Ab)X/g-I@  
} ]w9\q*S]  
~V!gHJ5M  

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public String getSFilePath() 20k@!BNq  
{ 222Mm/QN  
return sFilePath; nv2p&-e+  
} ^Y+P(o$HM  
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`@Tl7I\  
public void setSFilePath(String value) VF] ~J=>i  
{ H.]rH,8  
sFilePath = value; 1a>TJdoa  
} qrZ*r{3  
t,vj)|:  
@Rp#*{  
public String getSFileName() GFppcL@a  
{ <b$.{&K  
return sFileName; `37$YdX  
} akB+4?+s)  
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8ZPjzN>c6  
public void setSFileName(String value) n+9rx]W,  
{ #<EMG|&(  
sFileName = value; X4{O/G  
} |VxO ,[~  
r; pS_PV  
2~(\d\k  
public int getNSplitter() 1'Y7h;\~\  
{ ipdGAG  
return nSplitter; 6< O|,7=_  
} " }oH3L  
"Q
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public void setNSplitter(int nCount) gOL-b9W  
{ ;N;['xcx;  
nSplitter = nCount; M
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} ?f'iS#XL  
}  "yA=Tw  
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/* u
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**Utility.java Vnvfu!>(  
*/ I5mtr  
package NetFox; ;r.0=Uo9]  
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s !XJ   
public class Utility { %|\Af>o4d  
49d02AU%  
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public Utility() B
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{ +\/1V`  
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} [
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;V)jC  
//线程睡眠 2?)8s"Y  
public static void sleep(int nSecond) !)-)*T  
{ {#C)S&o)6  
try{ vtu!* 7m  
Thread.sleep(nSecond); c[<>e#s+;  
} wJMk%N~R:  
catch(Exception e) 2.PZtl  
{ _CImf1  
e.printStackTrace (); N3$%!\~O  
} c%x9.s<+1  
} %`)lCK)2  
>Sc/E}3  
//日志 o>i@2_r\&H  
public static void log(String sMsg) $/#F9>eZ  
{ tQWjNP~  
System.err.println(sMsg); b9RJ>K  
} Da-U@e!  
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J5"d|i  
public static void log(int sMsg) ,+GS.]8<  
{ 57(5+Zme  
System.err.println(sMsg); dKJ-{LV  
} yE{\]j|Zf  
} dC(5I{I|  
vTsMq>%,<  
C/#?S=w`4  
/* 9!?Ywc>0#  
**TestMethod.java )Lg~2]'?j  
*/ 'HJ<"<  
package NetFox; Z5eM  
4+:'$Nw  
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public class TestMethod { 8x LXXB  
8F[ ;ma>Z8  
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public TestMethod() @"A 5yD5
  
{ ///xx/weblogic60b2_win.exe 'DNxc  
try{ :
T?WN+3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); K*2s-,b *  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Mis B&Ok`k  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Vdefgq@<  
fileFetch.start(); l4.ql1BX@y  
} ?e4H{Y/M  
catch(Exception e){e.printStackTrace ();} mMOgx   
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@mv G=:k  
} [!wJIy?,  
t 4zUj%F  
wIR"!C>LE  
public static void main(String[] args) ='w 2"4  
{ ]\A=[T^  
new TestMethod(); l0URJRK{*  
} ks6iy}f7  
} 64mD%URT  
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