http断点续传简单实现（java)

/* 22CET9iCe  
**SiteFileFetch.java 6UeYZ g  
*/ v.jxG{~.  
package NetFox; RPW46l34  
import java.io.*; h<LFTYE@  
import java.net.*; =+!l8o&o,  
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public class SiteFileFetch extends Thread { cl%+m  
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SiteInfoBean siteInfoBean = null; //文件信息Bean hL&$` Q  
long[] nStartPos; //开始位置 aaR& -M@  
long[] nEndPos; //结束位置 ;XurH%Mg  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4a-JC"  
long nFileLength; //文件长度 =n5'~1?X?  
boolean bFirst = true; //是否第一次取文件 4KM-$h,4O  
boolean bStop = false; //停止标志 PW5]+ |#  
File tmpFile; //文件下载的临时信息 Cd}^&z  
DataOutputStream output; //输出到文件的输出流 \_ 3>v5k|  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） i7Up AHd/  
public SiteFileFetch(SiteInfoBean bean) throws IOException }uZs)UQ|$  
{ y QW7ng7D0  
siteInfoBean = bean; \l~^dn}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); V95o(c.p  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); nF,F#V8l  
if(tmpFile.exists ()) &<PIm  
{ P]43FPb  
bFirst = false; V\;Xa0  
read_nPos(); _B0(1(M<2  
} \wK&wRn)  
else f"ndLX:'}  
{ q!ZM Wg  
nStartPos = new long[bean.getNSplitter()]; |58HPW9
 
nEndPos = new long[bean.getNSplitter()]; !ZYPz}&N_  
} `x[Is$  
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} s<s}6|Z  
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public void run() k QuEG5n.-  
{ R~\R>\  
//获得文件长度 =yf)Z^  
//分割文件 s@F&N9oh  
//实例FileSplitterFetch r)*23&Ojs  
//启动FileSplitterFetch线程 fM
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//等待子线程返回 lG7PM^Eb
 
try{ =,6H2ew  
if(bFirst) MiT0!
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{ SYCL\b  
nFileLength = getFileSize(); -&1(~7  
if(nFileLength == -1) nkW})LyB\  
{ \MP~}t}c  
System.err.println("File Length is not known!"); W[ l  
} .XJ'2yKof  
else if(nFileLength == -2) 7n7Xyb  
{ XX8HSw!w  
System.err.println("File is not access!"); +%JBr+1#\  
} 5=pE*ETJ  
else Q^(CqQo!<  
{ P.Z:`P)  
for(int i=0;i<nStartPos.length;i++) paqGW]  
{ *N">93:  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =;rLv7(a  
} YM}a>o  
for(int i=0;i<nEndPos.length-1;i++) F]aoTy  
{ h?mDtMCw2  
nEndPos = nStartPos[i+1]; S,m(  
} 5\+*ml  
nEndPos[nEndPos.length-1] = nFileLength; +A| Bc~2!  
} Q|'f3\  
}
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//启动子线程 D:z'`v0j  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; uvId],dQ5  
for(int i=0;i<nStartPos.length;i++) #e'>9T  
{ VOEV[?>ss  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4p
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Bs"D<r&ro  
nStartPos,nEndPos,i); m2PUU/8B/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); uo#1^`P  
fileSplitterFetch.start(); J(7#yg%5  
} !oWB5x~:P  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), daE.y_9y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); S!(3-{nC  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", '`>%RZ]  
nEndPos = " + nFileLength); 7he73  
// fileSplitterFetch[nPos.length-1].start(); 1m*)MZ)  
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lLD
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//等待子线程结束 \V? .^/  
//int count = 0; mY"7/dw<v  
//是否结束while循环 8A>OQR  
boolean breakWhile = false; #l=yD]tPU  
1djZ5`+  
6{h\CU}"  
while(!bStop) GG%b"d-  
{ "#1\uoH  
write_nPos(); e?>  
Utility.sleep(500); d_9 Cm@  
breakWhile = true; y]db]pP5  
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for(int i=0;i<nStartPos.length;i++) q$:1Xkl  
{ RkYdK$|K  
if(!fileSplitterFetch.bDownOver) Y%KowgP\  
{ `"5Ub,~  
breakWhile = false; +A}t_u3<  
break; fap`;AuwK  
} r w?wi}}gn  
} 6jq*lnA%  
if(breakWhile) ;uBGB h<  
break; ;_<~9;  
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sxNf"C=-.  
//count++; 6}"%>9  
//if(count>4) )+_Vx}O:}  
// siteStop(); qG9a!sj   
} KF%BX~80C  
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System.err.println("文件下载结束！"); AyE*1 FD  
} @{/)k%U  
catch(Exception e){e.printStackTrace ();} "Z.6@ c7  
} p{Lrv%-j  
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,^/Wv!uPE  
//获得文件长度 ]Lv

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public long getFileSize() S\GWMB!oF  
{ 8E%
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int nFileLength = -1; #(^<qr  
try{ |AYii-g  
URL url = new URL(siteInfoBean.getSSiteURL()); 4 &bmt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7:4c\C0  
httpConnection.setRequestProperty("User-Agent","NetFox"); m$vq%[/#  
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MBWoPK  
int responseCode=httpConnection.getResponseCode(); LU
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if(responseCode>=400) \e86'&  
{ (0{Dn5MH  
processErrorCode(responseCode); 8zK#./0\  
return -2; //-2 represent access is error 'uu*DgEr  
} ]IuZT  
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String sHeader; ufXWK3~\  
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for(int i=1;;i++) N:`_Vl  
{ L=lSW
7R  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9z(SOzZn  
//Utility.log(in.readLine()); }B0[S_mw  
sHeader=httpConnection.getHeaderFieldKey(i); <"3q5ic/Z  
if(sHeader!=null) [jgVN w""D  
{ hK?GIbRZ  
if(sHeader.equals("Content-Length")) "r^RfZ;  
{ a%%7Ew ?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); EyK!'9~a  
break; M5I`
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} '\bokwsP  
} T+Yv5l  
else x^lcT  
break; )1At/
mr  
} a6Vfd&  
} a*p|Ij  
catch(IOException e){e.printStackTrace ();} 13?:a[~=Y  
catch(Exception e){e.printStackTrace ();} *7AB0y0k  
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Utility.log(nFileLength); u62H+'k}F  
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return nFileLength; Xt$qjtVM  
} 6wp1jN  
?mNB:-Q  
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//保存下载信息（文件指针位置） JD*HG]  
private void write_nPos() N@thew
t|  
{ Kbu>U{'  
try{ <X*oW".  
output = new DataOutputStream(new FileOutputStream(tmpFile)); & AK\Pw)  
output.writeInt(nStartPos.length); ]!ai?z%cK#  
for(int i=0;i<nStartPos.length;i++) .@{v{  
{ {V7mpVTX.  
// output.writeLong(nPos); (wu'FFJp#  
output.writeLong(fileSplitterFetch.nStartPos); Kw-<o!~  
output.writeLong(fileSplitterFetch.nEndPos); T
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} It3k
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output.close(); YP,,vcut
 
} a;[\nCK
 
catch(IOException e){e.printStackTrace ();} L2@:?WW[  
catch(Exception e){e.printStackTrace ();} L&6^(Bn  
} ULK]' Rn  
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//读取保存的下载信息（文件指针位置） ZX/FIxpy  
private void read_nPos() HzM\<YD  
{ pCt2-aam  
try{ i ;B^I8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >lIzeEW#  
int nCount = input.readInt(); fr~Eb'8  
nStartPos = new long[nCount]; O _9r-Zt^  
nEndPos = new long[nCount]; #?)6^uTW  
for(int i=0;i<nStartPos.length;i++) x<I[?GT=  
{ 3$"V,_TBZ  
nStartPos = input.readLong(); G$,s.MSf  
nEndPos = input.readLong(); ZV{C9S&  
} C]b:#S${  
input.close(); du$lS':`  
} 7 7bwYKIn  
catch(IOException e){e.printStackTrace ();} 2S_u/32]W  
catch(Exception e){e.printStackTrace ();} 4A+g-{d  
} 4D&L]eJ  
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private void processErrorCode(int nErrorCode) gw)z*3]~s  
{ 6wpW!SWD  
System.err.println("Error Code : " + nErrorCode); 
#~p;s>  
} cn}15JHdR  
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3>n&u,Xe  
//停止文件下载 xY?p(>(  
public void siteStop() 4- QlIIf  
{ }`CF(Do  
bStop = true; )ThNy:4  
for(int i=0;i<nStartPos.length;i++) C9+rrc@4  
fileSplitterFetch.splitterStop(); (-yi
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} u>;aQtK~  
} r)~?5d  
//负责部分文件的抓取 XHv m{z=  
**FileSplitterFetch.java 6n/=n%US  
*/ L{~ ]lUo  
package NetFox; ft7M9<#v  
n ^9?(a4u  
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import java.io.*; z?13~e[D  
import java.net.*; dWzf C@]  
}t#|
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public class FileSplitterFetch extends Thread { yl?LXc[)  
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String sURL; //File URL $cn8]*Z=  
long nStartPos; //File Snippet Start Position d7BpmM  
long nEndPos; //File Snippet End Position O-[YU%K3?  
int nThreadID; //Thread's ID F3V:B.C  
boolean bDownOver = false; //Downing is over  }c||$  
boolean bStop = false; //Stop identical N5)H(<}  
FileAccessI fileAccessI = null; //File Access interface AAfhh5i  
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 MMk9rBf  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2Bi]t%<{  
{ X"3p/!W.4  
this.sURL = sURL; mvH}G8  
this.nStartPos = nStart; y~*B%KnEQy  
this.nEndPos = nEnd; tX% C5k  
nThreadID = id; ,eTdQI;   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 G[e,7jev  
} 8;`B3N7  
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public void run() <VU-ja*(J  
{ I!Dx)>E&  
while(nStartPos < nEndPos && !bStop) 8\E=p+C  
{ R6X2d\l#  
8m H6?,@6  
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try{ =mQY%l  
URL url = new URL(sURL); b&A/S$*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wx-&(f   
httpConnection.setRequestProperty("User-Agent","NetFox"); +)h# !/  
String sProperty = "bytes="+nStartPos+"-"; zEQQ4)mA  
httpConnection.setRequestProperty("RANGE",sProperty); rhzI*nwOT  
Utility.log(sProperty); 2.JrLBhN  
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!!A(A^s  
InputStream input = httpConnection.getInputStream(); iLQO .'{U  
//logResponseHead(httpConnection); dH0>lV  
)/f#~$ws  
W|{!0
w  
byte[] b = new byte[1024]; f-^*p  
int nRead; ?0u"No52m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5O~xj:  
{ I;AS.y  
nStartPos += fileAccessI.write(b,0,nRead); ^x*J4jl  
//if(nThreadID == 1) :9&@/{W  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pHk$_t  
} wqm{f~nj=  
vR#MUKfh  
CBdr1  
Utility.log("Thread " + nThreadID + " is over!"); Y&M{7  
bDownOver = true; sMAH;'`!Eu  
//nPos = fileAccessI.write (b,0,nRead); &Odrq#o?R  
} xP9R d/xa|  
catch(Exception e){e.printStackTrace ();} IecD41%  
} 8WLh7[  
} y+wy<[u  
g<F+Ldgj  
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//打印回应的头信息 Gn6\n'r0  
public void logResponseHead(HttpURLConnection con) .@r{Tq,%q8  
{ H[g i`{c  
for(int i=1;;i++) EQ"_kJ>81Y  
{ 1IgTJ" \  
String header=con.getHeaderFieldKey(i); CNj |vYj  
if(header!=null) F*z>B >{)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {a>JQW5=  
Utility.log(header+" : "+con.getHeaderField(header)); UC`sq-n  
else ?3LV$S)U  
break; uFuH/(}K[  
} Pvv7|AV   
} mGwJ>'+d  
`nII@ !  
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public void splitterStop() C<QpUJ`k  
{ 7!o
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bStop = true; ho#<?rh_  
} rWJRoGk/  
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} -'
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]9<H[5>$R  
/* !#5y%Bf  
**FileAccess.java )g&nI<Mh  
*//文件访问(定位，写) u,@ac[!vP  
package NetFox; va(6?"9  
import java.io.*; &B+_#V=X@  
*c.w:DkfB  
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public class FileAccessI implements Serializable{ <|3F('Q"  
ok-q9dM  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _M>S=3w  
RandomAccessFile oSavedFile; cy8r}wD  
long nPos; SoCN.J30  
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public FileAccessI() throws IOException !t)uRJ   
{ {)Zz4  
this("",0);
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} A|mE3q=  
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su60j^e*  
public FileAccessI(String sName,long nPos) throws IOException EcR[b@YI  
{ t1#f*G5  
oSavedFile = new RandomAccessFile(sName,"rw"); 
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this.nPos = nPos; *xeJ4h  
oSavedFile.seek(nPos); 6!U~dt#a  
} E_z,%aD[  
! OVi\v 'm  
4/x.qoj  
public synchronized int write(byte[] b,int nStart,int nLen) tuo'Uk)  
{ :K \IS`  
int n = -1; \u/=?b  
try{ N>j*{]OY+{  
oSavedFile.write(b,nStart,nLen); *MWI`=c  
n = nLen; {Z$]Rj  
} T
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catch(IOException e) lP(<4mdP  
{ grd fR`3  
e.printStackTrace (); #b&=CsW`  
} aXbj pb+  
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return n;
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} X-"0Zc  
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} Pj^Ccd'>=  
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/* CS xB)-  
**SiteInfoBean.java y+.(E-g  
*/ :bP <H  
package NetFox; SwH#=hg  
H[/^&1P  
1(VskFtZF  
public class SiteInfoBean { Ban"H~  
NA$ODK-  
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private String sSiteURL; //Site's URL .6i +_B|  
private String sFilePath; //Saved File's Path NCx)zJ\S  
private String sFileName; //Saved File's Name ^X*l&R_=R  
private int nSplitter; //Count of Splited Downloading File p!(]`N  
J B  !Q  
DC$
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public SiteInfoBean() (jh0cy}|]  
{//nSplitter的缺省值为5 B/EGaYH  
//default value of nSplitter is 5 {RH)&k&%  
this("","","",5); Fz$^CMw5K  
} Nu}Zsb|{  
!`dn# j  
rI
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ({t6Cbw  
{ ( 2KopL  
sSiteURL= sURL; |uA /72  
sFilePath = sPath; {'zs4)vw  
sFileName = sName; pmDFmES  
this.nSplitter = nSpiltter; oPA m*  
s.!gsCQme  
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} 74~%4  
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public String getSSiteURL() n6GB2<y  
{ rdm&YM`J  
return sSiteURL; ,HW[l.v  
} eOd'i{f@F  
mLeK7?GL  
VSm{]Z!x  
public void setSSiteURL(String value) 2MKB(;k  
{ 9C1\?)"D^e  
sSiteURL = value; l9$"zEC  
} [Kanj/  
oSs~*
mf  
j{NcDepLn  
public String getSFilePath() %y\  
{ gs=(h*  
return sFilePath; <~.1>CI9D3  
} k Rp$[^ma  
}$'T=ay&  
h\OMWJ~  
public void setSFilePath(String value) $C&E3 'O  
{ SfwNNX%  
sFilePath = value; ~$ "P\iJ  
} * @'N/W/8  
wEb10t,  
>VvA&p71b  
public String getSFileName() ,fD#)_\g2  
{ (yhnvZ  
return sFileName; MvlqxJ$  
} oei2$uu  
#;>v,Jo  
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public void setSFileName(String value) 2xpI|+a%  
{ |VML.u:N  
sFileName = value; hW-?j&yJ?  
} e:RgCDWL  
XRWy#Pj  
agPTY{;  
public int getNSplitter() 10e~Yc  
{ 1ihdH1rg[  
return nSplitter; [-JU(:Rh  
} zM|Y X<  
C.9l${QU  
ABnJ{$=n#  
public void setNSplitter(int nCount) %pImCpMR  
{ 6n$g73u<=3  
nSplitter = nCount; ~~3 BV,  
} xE
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} R"qxT.P(  
`"qSr%|  
nHF%PH#|o  
/* IkJ-*vI6  
**Utility.java 2umgF  
*/ 96S#Q*6+R  
package NetFox; 4oRDvn7f&  
!"QvV6Lq\  
Xg1QF^  
public class Utility { aO$I|!tl  
'@,M 'H{  
4:Id8rzz  
public Utility() ?=0BU}  
{ Bh<6J&<n  
OS$^>1f"  
4,qhWe`/  
} jq12,R2+)  
{Z(kzJwN  
//线程睡眠 tsN,yI]-VA  
public static void sleep(int nSecond) Z+G/==%3#,  
{ 4b:q84  
try{ <e@+w6Kp'7  
Thread.sleep(nSecond); QL`Hb p  
} qjmlwVw  
catch(Exception e) *VgiJ  
{ xy[aZr  
e.printStackTrace (); K+@R [  
} Q6rvTV'vv  
} R*r;`x  
@pO2A6Ks  
//日志 4
|Ay;}X \  
public static void log(String sMsg) 8XdgtYm  
{ S!+}\*  
System.err.println(sMsg); eNX!EN(^  
} x /E<@?*:  
%{;1i  
7HM%Cd  
public static void log(int sMsg) YzVhNJ
Wpw  
{ ![j?/376  
System.err.println(sMsg); IcP\#zhEv  
} &*8_w-  
} 6#(==}Sm+  
V(3=j)#  
jPa"|9A  
/* V3<H8pL  
**TestMethod.java CWw#0  
*/ b ]u01T-  
package NetFox; %+HZ4M+hV  
yU'<b.]  
T?HW=v_a  
public class TestMethod { }YCpd)@  
0<#>LWaM_  
GYwU3`{  
public TestMethod() jcL%_of  
{ ///xx/weblogic60b2_win.exe  aK33bn'j  
try{ a(oa?OdJ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L(
+
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); U;#9^<^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); T1#r>3c\  
fileFetch.start(); :kQydCuK  
} 2R];Pv  
catch(Exception e){e.printStackTrace ();} 8(ej]9RObU  
lgQ
"K(zY  
!!?TkVyEyM  
} ~EtwX YkRZ  
x>$e*  
x7ZaI{ 
 
public static void main(String[] args) FS^~e-A  
{ cK.z&y0]  
new TestMethod(); 85?;\5%-  
} i8->3uB  
} ,9Si3vn  
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