http断点续传简单实现（java)

/* ( C~
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**SiteFileFetch.java F[5sFkM7  
*/ |EZ\+!8N:{  
package NetFox; ?K!^[aO}=  
import java.io.*; {W11+L{8  
import java.net.*; .EB'n{zxd  
+zL|j/q?  
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public class SiteFileFetch extends Thread { jxdX
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SiteInfoBean siteInfoBean = null; //文件信息Bean lK"m|Z  
long[] nStartPos; //开始位置 LM2S%._cj;  
long[] nEndPos; //结束位置 u.rFZu?E\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 #<o=W#[  
long nFileLength; //文件长度 \u$[$R5  
boolean bFirst = true; //是否第一次取文件 %/}46z9\  
boolean bStop = false; //停止标志 uFYcVvbT@  
File tmpFile; //文件下载的临时信息 0?Bv zfb  
DataOutputStream output; //输出到文件的输出流 59#o+qo4  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ,JqCxb9  
public SiteFileFetch(SiteInfoBean bean) throws IOException epGC Ta  
{ 4'#?"I  
siteInfoBean = bean; Y_= ]w1  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); wB+X@AA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _@@.VmZL  
if(tmpFile.exists ()) M97MIku~9  
{ 0Z1';A3  
bFirst = false; &HB!6T/  
read_nPos(); {v}BtZ  
} (Tv~$\=  
else V/Q/Uj
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{ GQ\;f  
nStartPos = new long[bean.getNSplitter()]; i)q8p  
nEndPos = new long[bean.getNSplitter()]; ?p&( Af)  
} f-`C1|\w  
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} Q" G;L  
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public void run() Sb.%B^O  
{ ^l{q{O7U$  
//获得文件长度 SNc$!  
//分割文件 M \UB r4  
//实例FileSplitterFetch 2" u,f  
//启动FileSplitterFetch线程 ,}/6Za  
//等待子线程返回 Xbu P_U'  
try{ cRv#aV  
if(bFirst) \:Q)X$6  
{ ~EM(*k._  
nFileLength = getFileSize(); W H%EC$  
if(nFileLength == -1) H,EGB8E2  
{ ^&KpvQNW_  
System.err.println("File Length is not known!"); uxlrJ1~M  
} -5Oy k,  
else if(nFileLength == -2) 8'M:uI  
{ #ri;{
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System.err.println("File is not access!"); r3dGXiu  
} >%LY0(hY3  
else 4{ [d '-H5  
{ `_SV1|=="8  
for(int i=0;i<nStartPos.length;i++) `L%<3/hF  
{ W<:x4gBa  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ` <u2 N  
} p8j*m~4B  
for(int i=0;i<nEndPos.length-1;i++) o37D~V;  
{ m(`O>zS  
nEndPos = nStartPos[i+1]; |nBs(>b  
} m qwJya  
nEndPos[nEndPos.length-1] = nFileLength; ]CDUHz  
} z"-oD*ICw  
} )Em`kle  
"c+$GS  
4 %V9  
//启动子线程 ~ ReX$
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; *U-:2u
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for(int i=0;i<nStartPos.length;i++) 5\}E4y  
{ 5A+@xhRf  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -$$mrU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -us:!p1T  
nStartPos,nEndPos,i); H5*#=It  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @w;$M]o1  
fileSplitterFetch.start(); <[K3Prf C  
} [Sj"gLj  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^SK!?M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); v3{%U1>}v  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", V9jxmu F,  
nEndPos = " + nFileLength); +ViL"  
// fileSplitterFetch[nPos.length-1].start(); Z5 7.+z<  
2@IL  n+#  
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//等待子线程结束 USaa#s4'  
//int count = 0; ]E)\>Jb  
//是否结束while循环 bGkLa/?S  
boolean breakWhile = false; j+e~ tCcN/  
+d7Arg!m  
7!wc'~;  
while(!bStop) vK`HgRQ(C  
{ \XwC|[%P  
write_nPos(); QN|=/c<U  
Utility.sleep(500); q|0l>DPRp  
breakWhile = true; 3V7WIj<  
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for(int i=0;i<nStartPos.length;i++) XE&h&v=>  
{ IZ\fvYp  
if(!fileSplitterFetch.bDownOver) iSUu3Yv,_m  
{ O /:FY1  
breakWhile = false; EJRkFn8XG'  
break; (&v,3>3]  
} 0Lb{HLT  
} Ftd,dqd  
if(breakWhile) ,LP^v'[V7  
break; a>rDJw:  
QPh3(K1w^  
><>%;HZ  
//count++; bwcr/J(Nb  
//if(count>4) y. 1F@w|  
// siteStop(); /h{Rf,H  
} z@w}+fYO  
Jgg<u#  

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System.err.println("文件下载结束！"); 13w(Tf  
} g<,0kl2'S  
catch(Exception e){e.printStackTrace ();} vU5}E\Ny  
} 6GPI gPL,  
wW/q#kc  
X/90S2=P  
//获得文件长度 c8Ud<M .  
public long getFileSize() Zd%wX<hU"  
{ V"'PA-z3  
int nFileLength = -1; pPag@L  
try{ $45.*>,  
URL url = new URL(siteInfoBean.getSSiteURL()); V0#Ocq,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (>f`>6 V  
httpConnection.setRequestProperty("User-Agent","NetFox"); eG8l^[  
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k  
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int responseCode=httpConnection.getResponseCode(); U*E)y7MY  
if(responseCode>=400) \G7F/$
g  
{ =6O*AJ  
processErrorCode(responseCode); -u
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return -2; //-2 represent access is error 8D,*_p  
} s;=C&N5g  
-u4")V>  
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String sHeader; R dwt4A+  
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for(int i=1;;i++) -zn_d]NV  
{ 5V\",PAW  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); JAP(J~  
//Utility.log(in.readLine()); 3fB]uq+eD%  
sHeader=httpConnection.getHeaderFieldKey(i); (Nk[ys}%*  
if(sHeader!=null) v3FdlE  
{ 2<y9xvp  
if(sHeader.equals("Content-Length")) |#M|"7;2z  
{ *8m['$oyV  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); z7gX@@T  
break; DcdEt=\)h  
} Hh*?[-&r~  
} xE]y*\  
else yz=X{p1  
break; \q4r/SbgW  
} ' |B3@9<  
} <F(2D<d{;)  
catch(IOException e){e.printStackTrace ();} {>9ED.t  
catch(Exception e){e.printStackTrace ();} |3yG  
#0Y_!'j  
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Utility.log(nFileLength); qIQRl1Tw;V  
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return nFileLength; )RvX}y-  
} g#^MO]pY  
Iz#4!E|<  
.(.
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//保存下载信息（文件指针位置） !|i #g$  
private void write_nPos() z F.@rXl  
{ 
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try{ ujSoWs  
output = new DataOutputStream(new FileOutputStream(tmpFile)); n=C"
pH#  
output.writeInt(nStartPos.length); m,!SDCq  
for(int i=0;i<nStartPos.length;i++) fFqYRK  
{ @sA!o[gH  
// output.writeLong(nPos); '&B4Ccn<V  
output.writeLong(fileSplitterFetch.nStartPos); H~nZ=`P9&  
output.writeLong(fileSplitterFetch.nEndPos); FX|&o>S(8  
} {&mHfN  
output.close(); >h#w~@e::  
} Es)|#0m\x@  
catch(IOException e){e.printStackTrace ();} Y$\|rD^f  
catch(Exception e){e.printStackTrace ();} matna  
} c>{QTI:]  
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2M'dTXz  
//读取保存的下载信息（文件指针位置） $*iovam>^]  
private void read_nPos() ]VLseF  
{ 3oMHy5  
try{ ZIc.
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _UP
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int nCount = input.readInt(); o!KDeY  
nStartPos = new long[nCount]; dCTyfXou[=  
nEndPos = new long[nCount]; OQB7C0+ &  
for(int i=0;i<nStartPos.length;i++) HNv~ZAzBG-  
{ Cd"{7<OyM4  
nStartPos = input.readLong(); wN4#j}C  
nEndPos = input.readLong(); ]lBCK  
} dp'[I:X  
input.close(); ceJi|`F  
} ?X6}+  
catch(IOException e){e.printStackTrace ();} ]4en|Aq  
catch(Exception e){e.printStackTrace ();} n"6L\u  
} QO(F%&v++  
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private void processErrorCode(int nErrorCode) orjtwF>^  
{ p9"dm{  
System.err.println("Error Code : " + nErrorCode); UT;%I_i!'  
} D;en!.[Z  
m.D8@[y  
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//停止文件下载 N<Sl88+U  
public void siteStop() Ul8HWk[6Iw  
{ 1KZigeHXI  
bStop = true; ?UsCSJ1V  
for(int i=0;i<nStartPos.length;i++) z~t0l  
fileSplitterFetch.splitterStop(); VeQGdyhY  
\5a.JfF  
Mt.Cj;h@^[  
} /43l}6I  
}
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//负责部分文件的抓取 }m+Q
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**FileSplitterFetch.java #D9.A7fCc5  
*/ \,13mB6  
package NetFox; '8 .JnCg  
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riW9l6s'  
import java.io.*; J _rrc;F  
import java.net.*; }ny7LQ  
#B\s'j[A"  
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public class FileSplitterFetch extends Thread { k A3K  
toGiG|L  
w[X-Q+7p(t  
String sURL; //File URL }u;K<<h:  
long nStartPos; //File Snippet Start Position x,C8):\t`B  
long nEndPos; //File Snippet End Position LK}
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int nThreadID; //Thread's ID 6Z|h>H5a  
boolean bDownOver = false; //Downing is over 3dN`Q:1R9  
boolean bStop = false; //Stop identical p7QZn.,=u  
FileAccessI fileAccessI = null; //File Access interface /?;'y,(Q  
fXMY.X>f  
p_I^7 $  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v>keZZOs  
{ b-ss^UL  
this.sURL = sURL; ==Egy:<:Q  
this.nStartPos = nStart; 4aArxJ  
this.nEndPos = nEnd; @ki|#ro  
nThreadID = id; '~Y@HRVL@|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _:[@zxT<x  
} }U8v ~wcd  
v@EErF  
O50_qu33ju  
public void run() ),yar9C  
{ YZ>L_$:q  
while(nStartPos < nEndPos && !bStop) x$q}lJv_  
{ z)M#9oAM  
'I>USl3hI  
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try{ |$\K/]q-  
URL url = new URL(sURL); 1["i,8zB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w=#'8ZuU  
httpConnection.setRequestProperty("User-Agent","NetFox"); sJZ2e6?n  
String sProperty = "bytes="+nStartPos+"-"; [W3X$r~-  
httpConnection.setRequestProperty("RANGE",sProperty); wQG?)aaM  
Utility.log(sProperty); ,ayEZ#4.m  
!=eNr<:V.  
glLVT i  
InputStream input = httpConnection.getInputStream(); W{-g?)Tou  
//logResponseHead(httpConnection); lqfTF  
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byte[] b = new byte[1024]; x*H#?.E  
int nRead; +j{Cfv$do  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) =!t;e~^8]  
{ S]fu M%  
nStartPos += fileAccessI.write(b,0,nRead); 5, $6mU#=  
//if(nThreadID == 1) OMK,L:poC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JlYZ\  
} @<P2di  
n~UI47  
wH?)ZL  
Utility.log("Thread " + nThreadID + " is over!"); + ,Krq 3P  
bDownOver = true; l/={aF7+  
//nPos = fileAccessI.write (b,0,nRead); [2-n*a(q  
} *k7BE_&*0Z  
catch(Exception e){e.printStackTrace ();} kqCsEtm]  
} A'#d:lOA  
} -gvfz&Lz  
\2kLj2!  
&%rM|  
//打印回应的头信息 l Xa/5QKC  
public void logResponseHead(HttpURLConnection con) '^TeV=  
{
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for(int i=1;;i++) Jw _>I  
{ 'Ou C[$Z  
String header=con.getHeaderFieldKey(i); .=;IdLO,Bf  
if(header!=null) @dv8 F "v  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?JZ$M  
Utility.log(header+" : "+con.getHeaderField(header)); Tc(=J7*r&  
else Dizz?O  
break; nh4G;qdU  
} 7_\F$bp`  
} !p+54w\ 2  
4-.W~C'Q  
WGz)-IB!PE  
public void splitterStop() k&ooV4#f6  
{ MS\vrq'_  
bStop = true; ?=9'?K/~a  
} 4`
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)I&.6l!#  
t~(jA9n  
} p=:Vpg<!  
ZGZNZ}~#  
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/* nsI+04[F  
**FileAccess.java Mw0>p5+ cy  
*//文件访问(定位，写) o*)Sg6Yk  
package NetFox; ynmjIQ  
import java.io.*; -
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0o+Yjg>\~8  
;~<To9O  
public class FileAccessI implements Serializable{ ^7yt>  
3`cA!
ZVQ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 GCJ[xn(_  
RandomAccessFile oSavedFile; |BFzTz,o  
long nPos; /:F^*
]  
M/6Z,oOU  
jae9!Wi  
public FileAccessI() throws IOException d 5yEgc;z  
{ XY| y1L 3[  
this("",0); 44}5o  
} f7a4E+}  
gbuh04#~  
Y]SF0:v!n  
public FileAccessI(String sName,long nPos) throws IOException o*H U^  
{ >>J3"XHX  
oSavedFile = new RandomAccessFile(sName,"rw"); 5(H%Ia  
this.nPos = nPos; upuN$4m&{  
oSavedFile.seek(nPos); dLp1l2h!0  
} tfU*U>j  
o=YOn&@%  
M?lh1Yu"  
public synchronized int write(byte[] b,int nStart,int nLen) O#U maNj/  
{ ."+lij=56  
int n = -1; ~gpxK{  
try{ Kd-
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oSavedFile.write(b,nStart,nLen); 
)bFl-  
n = nLen; F(hPF6Zx(  
} R `tJ7MB  
catch(IOException e) 3Cj)
upc  
{ I&+.IK_  
e.printStackTrace (); w&?XsO@0W  
} nW)+-Wxq  
N_T5sZ\  
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return n; w~u{"E$  
} 8Nzn%0(Q  
$Er=i }`  
'V7LL1K^>  
} wGti|7Tu*  
vntJe^IaFd  
AU\=n,K7  
/* *Y(59J2  
**SiteInfoBean.java Y]([K.I=  
*/ 1w=.vj<d8  
package NetFox; vb=]00c  
~Y/A]N86,  
Em(_W5 ND{  
public class SiteInfoBean { 57q=  
M)ET1ZM  
K+`GVmD  
private String sSiteURL; //Site's URL NTt4sWP!I  
private String sFilePath; //Saved File's Path ipn-HUrE@  
private String sFileName; //Saved File's Name DDr\Kv)k(  
private int nSplitter; //Count of Splited Downloading File <2
)AbI+3  
2G~{x7/[@  
|3FI\F;^q  
public SiteInfoBean() 9F807G\4Qt  
{//nSplitter的缺省值为5 \< .BN;t{  
//default value of nSplitter is 5 y[XD=j  
this("","","",5); st)is4  
} Z^V;B _  
{}$rN@OM$  
"\@J0|ppb  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ve(<s  
{ dCoP qKy  
sSiteURL= sURL; Gt&yz"?D  
sFilePath = sPath; %"f85VfZ  
sFileName = sName; 9Q1%+zjjMq  
this.nSplitter = nSpiltter; CC=I|/mBM  
>\1twd{u]  
L"'=[O~  
} -4x! #|]  
&`qYe)1Eo  
TAUl{??,  
public String getSSiteURL() sa+ JN^[X  
{ o:#jvi84F  
return sSiteURL; eF%M2:&c;  
} 9W=(D|,
,  
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edMCj  
public void setSSiteURL(String value) GUu8 N  
{ R%3yxnM*  
sSiteURL = value; 9^!.!%6O$  
} 9YI@c_1 Q  
;((t|  
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public String getSFilePath() XdJD"|,h  
{ 8~(,qU8-N  
return sFilePath; \r IOnZ.WK  
} Hpix:To  
+1wEoU.l2  
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public void setSFilePath(String value) ?>+
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{ ={xRNNUj_  
sFilePath = value; ;:=j{,&dl[  
} FC+-|1?C  
vT#R>0@mi  
}`L;.9  
public String getSFileName() jP<6J(  
{ "=Z=SJ1D  
return sFileName; fL|9/sojz  
} yr+QV:oVA  
f1:>H.m`  
-Cvd3%Jje  
public void setSFileName(String value) |vd|;" `  
{ \Yj_U'2"i  
sFileName = value; WblH}  
} QyA^9@iVs  
#Tc`W_-  
e5AsX.kvB  
public int getNSplitter() 0dwD ?GG2  
{ ^JxVs 7  
return nSplitter; 6/cm TT$i  
} t?&;   
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7a_8007$l  
public void setNSplitter(int nCount) 9%kO%j,3  
{ <&[`
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nSplitter = nCount; s>L-0vG  
} dUB;ZB7  
} =eY  
+ase>'<N#  
GdC=>\]  
/* <!t;[ie?y  
**Utility.java Gu{1%bb#kL  
*/ |d&Kr0QIV  
package NetFox; c*#$sZ@YA  
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.?#Q(eLj  
public class Utility { @B0fRG y  
@8\0@[]  
v3[ZPc;;  
public Utility() q>%.zc[x  
{ rui
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BT(eU*m-  
,r3`u2)  
} EQoK\.; G~  
I.t)sf,  
//线程睡眠 k
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public static void sleep(int nSecond) elM<S3  
{ UHV"<9tk  
try{ \gT({XU?  
Thread.sleep(nSecond); q !}~c  
} vZQraY nJ  
catch(Exception e) (Qw>P42J  
{ ,I|^d.[2  
e.printStackTrace (); jKcl{',  
} }`Wo(E}O  
} >G1]#'6;  
iPCn-DoIS  
//日志 'xuxMav6m  
public static void log(String sMsg) w?_'sP{pd  
{ fvta<  
System.err.println(sMsg); }x6)}sz7  
} = <A0;  
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hH$9GL{H  
public static void log(int sMsg) S^1ZsD.  
{ ??Urm[Y
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System.err.println(sMsg); a
"}ndrc*  
} ]/p>p3@1C  
} pQZ`dS\  
!`H!!Kg0L  
c;KMox/  
/* BQ,749^S  
**TestMethod.java  f^}n#  
*/ 4<<eqxI$|  
package NetFox; MYJMZ3qBi  
1e9~):C~W  
J10/pS  
public class TestMethod { C5KUIOg  
kg(}%Ih  
asQ^33g z  
public TestMethod() wk?i\vm  
{ ///xx/weblogic60b2_win.exe 6e|uA7i4  
try{ D1ik*mDA=  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Lf.Ia*R:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); {Gh9(0,B?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $? Z}hU  
fileFetch.start(); f\hQ>MLzt  
} #xR=U"  
catch(Exception e){e.printStackTrace ();} > B;YYj~f}  
lwG)&qyVd  
rw 2i_,.*~  
} B}zBbB  
;*Mr(#R  
!gsrPM  
public static void main(String[] args) ^!O!HMX0  
{ a&kt!%p:  
new TestMethod(); B$OV^iwxK  
} 6 %`h2Z  
} p")"t`k7  
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