http断点续传简单实现（java)

/* y1jCg%'H  
**SiteFileFetch.java H
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*/ <VMGTBVQ  
package NetFox; TNT4<5Ol6  
import java.io.*; F/,NDZN  
import java.net.*; t4."/.=+  
9R!atPz9  

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public class SiteFileFetch extends Thread { F$y$'Rzu_B  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Co9^OF-k  
long[] nStartPos; //开始位置 ;>%r9pz
~  
long[] nEndPos; //结束位置 (R,#a *CV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9!ngy*\x  
long nFileLength; //文件长度 RN1y^`  
boolean bFirst = true; //是否第一次取文件 ].avI
tg  
boolean bStop = false; //停止标志 r8t}TU>C  
File tmpFile; //文件下载的临时信息 j7Yu>cr  
DataOutputStream output; //输出到文件的输出流 @Myo'{3vF  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） '&P%C" 5  
public SiteFileFetch(SiteInfoBean bean) throws IOException >>4qJ%bL  
{ %"i(K@  
siteInfoBean = bean; d(ZO6Nr Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ^`i#$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^x]r`b  
if(tmpFile.exists ()) :I]Mps<  
{ B9_X;c  
bFirst = false; !NK1MU?T)  
read_nPos(); ~Py`P'+  
} ;DQ ZT  
else  \{_q.;}  
{ RT4x\&q  
nStartPos = new long[bean.getNSplitter()]; q_:4w$>  
nEndPos = new long[bean.getNSplitter()]; w?PkO p  
} Qab>|eSm  
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} df8k7D;~e  
l ~"^7H?4e  
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public void run() @(w@e\Bq  
{ {f_={k  
//获得文件长度 7DogM".}~Q  
//分割文件 5+4IN5o]=  
//实例FileSplitterFetch >a<.mU|#  
//启动FileSplitterFetch线程 Pjf"CW+A  
//等待子线程返回 VcE:G#]5  
try{ JJ-( Sl  
if(bFirst) UkwP  
{ d UE,U=  
nFileLength = getFileSize(); .<0ye_S'y  
if(nFileLength == -1) 98c(<  
{ )th<,Lo3#  
System.err.println("File Length is not known!"); 0@0w+&*"@  
} dmtr*pM_  
else if(nFileLength == -2) wQl ,  
{ tPWLg),  
System.err.println("File is not access!"); &GO}|W  
} /|m2WxK)  
else <Xhm`rH  
{ ];$L &5^  
for(int i=0;i<nStartPos.length;i++) s*KhF'fN  
{ XAKs0*J>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); h]&GLb&<?  
} hg]]Ok~cAs  
for(int i=0;i<nEndPos.length-1;i++) 3PWL@>zi  
{ W&W5lArr  
nEndPos = nStartPos[i+1]; #<"~~2?  
} JPI3[.o  
nEndPos[nEndPos.length-1] = nFileLength; |)DGkOtd  
} mkk6`,ov  
} sRR(`0Zp  
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//启动子线程 F@jZ
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VR8-&N  
for(int i=0;i<nStartPos.length;i++) WF+99?75  
{ V]6dscQ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;6 D@A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ea2ayT  
nStartPos,nEndPos,i); 9Q^r O26+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wo{gG?B  
fileSplitterFetch.start(); )gUR@V>e2  
} \fLMr\LL&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \A#41  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Igt#V;kK"2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", LKB$,pR~1l  
nEndPos = " + nFileLength); \;,+  
// fileSplitterFetch[nPos.length-1].start(); cGzPI+F  
OX0%C.K)hZ  
i v38p%Zm  
//等待子线程结束 :uS\3toj  
//int count = 0; =U9*'EFr  
//是否结束while循环 &vMb_;~B  
boolean breakWhile = false; DH!~ BB;  
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while(!bStop) h 0Q5-EA  
{ `:K
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write_nPos(); !sP{gi#=  
Utility.sleep(500); <oV(7  
breakWhile = true; CNyIQ}NJ  
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for(int i=0;i<nStartPos.length;i++) -zgI_u9=EB  
{ hBUn \~z  
if(!fileSplitterFetch.bDownOver) nPl?K
:(  
{ Z]Cq3~l  
breakWhile = false; n0 {i&[I~+  
break; 9wwqcx)3(  
} OX!tsARC@  
} ~rKrpb]ow  
if(breakWhile) I;|B.j  
break; sY Q
k  
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//count++; x~~|.C,  
//if(count>4) wKxtre(v  
// siteStop(); dn
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} }<SQ  
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System.err.println("文件下载结束！"); n
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} }2.`N%[  
catch(Exception e){e.printStackTrace ();} WX?IYQ+  
} J=I:CD%  
Y"aJur=`  
)9`qG:b'  
//获得文件长度 l<LI7Z]A  
public long getFileSize() 6SkaH<-&K  
{ d.d/<  
int nFileLength = -1; vJ[^K  
try{ 6ojo :-%Vf  
URL url = new URL(siteInfoBean.getSSiteURL()); }rw
8PZ9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); WlC:l  
httpConnection.setRequestProperty("User-Agent","NetFox"); f+,qNvBY/  
[!#L6&:a8  
w-MCZwCr)  
int responseCode=httpConnection.getResponseCode(); q"8ea/  
if(responseCode>=400) Fj3a.'  
{ /]Md~=yNp  
processErrorCode(responseCode); h2]P]@nW;W  
return -2; //-2 represent access is error xj;H&swo  
} ~IBP|)WA-  
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String sHeader; @,7GaK\  
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for(int i=1;;i++) K;H&n1  
{ f+)L#>Gl?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); C1n>M}b  
//Utility.log(in.readLine()); qWPkT$ u  
sHeader=httpConnection.getHeaderFieldKey(i); rcG"o\g@+  
if(sHeader!=null) ,m|h<faZL
 
{ u^I|T.w<r6  
if(sHeader.equals("Content-Length")) j-}O0~Jz  
{ }!.(n=idZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); YZ8>OwQz2  
break; 0-Ku7<a  
} V5>B])yQ  
} )'cMYC  
else yjJ5>cg  
break; @:vwb\azVD  
} `kXs;T6&  
} ]Q3ADh  
catch(IOException e){e.printStackTrace ();} \?k'4rH  
catch(Exception e){e.printStackTrace ();} 0znR0%~  
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Utility.log(nFileLength); wE`]7mA  
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return nFileLength; wc4{)qDE  
} Fq<A  
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2eY_%Y0  
//保存下载信息（文件指针位置） bwMm#f  
private void write_nPos() o|<!"AD7  
{ 8wFJ4v3  
try{ B%6)}Nl[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Z=o2H Bm7  
output.writeInt(nStartPos.length); 3bH'H*2  
for(int i=0;i<nStartPos.length;i++) }9OC,Y8?D  
{ j6 z^Tt12  
// output.writeLong(nPos); &@OT*pNna  
output.writeLong(fileSplitterFetch.nStartPos); x g  
output.writeLong(fileSplitterFetch.nEndPos); vX
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} ;dgp+  
output.close(); f46t9dxp$  
} PKiy5D*8p  
catch(IOException e){e.printStackTrace ();} =-n}[Y}A  
catch(Exception e){e.printStackTrace ();} nmKp[-5  
} [h
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//读取保存的下载信息（文件指针位置） ;[OH(
!  
private void read_nPos() &}B|"s[  
{ [sjosV  
try{ 4!no~ $b  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q/0Tj]D  
int nCount = input.readInt(); 7;wd(8  
nStartPos = new long[nCount]; `|&O*`  
nEndPos = new long[nCount]; @lrztM
 
for(int i=0;i<nStartPos.length;i++) 
-
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{ Pu$Tk|  
nStartPos = input.readLong(); ;iL#7NG-R  
nEndPos = input.readLong(); X\qNG]  
} Fywv  
input.close(); Hf2_0wA3  
} RMu~l@  
catch(IOException e){e.printStackTrace ();} <R=Zs[9M1  
catch(Exception e){e.printStackTrace ();} lzVq1@B  
} /t$d\b17pX  
{B*s{{[/'  
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private void processErrorCode(int nErrorCode) >!1-lfa8
 
{ vV-`jsq20H  
System.err.println("Error Code : " + nErrorCode); w%jII{@,  
} A#iV=76_  
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M!D3}JRm  
//停止文件下载 `7V]y-  
public void siteStop() 56kI 5:  
{ [5Mr@f4I  
bStop = true; ~U&AI1t+J  
for(int i=0;i<nStartPos.length;i++) [?N~s:}  
fileSplitterFetch.splitterStop(); Cjlk  
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} BuXqd[;K%  
} M@v.c;Lt  
//负责部分文件的抓取 Ne1$ee.NE  
**FileSplitterFetch.java Si;H0uPO  
*/ MeZf*' J  
package NetFox; F0Yd@Lk$_  
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import java.io.*; "'?>fe\qG  
import java.net.*; ^9:Z7 >Z  
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public class FileSplitterFetch extends Thread { ^WWQI+pk  
&7tbI5na@  
vy:Z/1q  
String sURL; //File URL >7DhTM-A  
long nStartPos; //File Snippet Start Position 5vnrA'BhBU  
long nEndPos; //File Snippet End Position 4zFW-yy  
int nThreadID; //Thread's ID @?]RBX?a  
boolean bDownOver = false; //Downing is over 5#E`=C%  
boolean bStop = false; //Stop identical &`2)V;t  
FileAccessI fileAccessI = null; //File Access interface 8$Y9ORs4  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException f x+/C8GK  
{ iSs:oH3l  
this.sURL = sURL; ri-b=|h2j  
this.nStartPos = nStart; 1\I}2
;  
this.nEndPos = nEnd; q9s=~d7  
nThreadID = id; Jij*x>K>y  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;vjOUn[E  
} V1B5w_^>h'  
p9{mS7R9T  
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public void run() tf`^v6m%]  
{ ds[|   
while(nStartPos < nEndPos && !bStop) qF;|bF  
{ 9V*qQS5<p  
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try{ /aZ`[m2  
URL url = new URL(sURL); $*=<Yw
4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bY~pc\V:`w  
httpConnection.setRequestProperty("User-Agent","NetFox"); PALc;"]O  
String sProperty = "bytes="+nStartPos+"-"; oe-\ozJ0  
httpConnection.setRequestProperty("RANGE",sProperty); aO4?m+  
Utility.log(sProperty); {;6`_-As%  
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InputStream input = httpConnection.getInputStream(); kc&U'&RgY  
//logResponseHead(httpConnection); \(2sW^fY  
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byte[] b = new byte[1024]; 40m-ch6Q  
int nRead; P71Lqy)5}A  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -PR N:'T  
{ W
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nStartPos += fileAccessI.write(b,0,nRead); C!bUI8x z  
//if(nThreadID == 1) E+;7>ja  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); </*6wpN  
} h2fNuu"  
7WZ+T"O{I  
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Utility.log("Thread " + nThreadID + " is over!"); {9q4)R}G  
bDownOver = true; k~nBiV  
//nPos = fileAccessI.write (b,0,nRead); Oxd]y1  
} ]~3V}z,T*  
catch(Exception e){e.printStackTrace ();} j|#Bo:2km  
} 9p(.A$  
} %._.~V  
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//打印回应的头信息 XlR@pr6tw  
public void logResponseHead(HttpURLConnection con) o!A+&{  
{ E hMNap}5"  
for(int i=1;;i++) z-)O9PV  
{ Lw>N rY(Y  
String header=con.getHeaderFieldKey(i); BnasI;yWb  
if(header!=null) wz%NbLy-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?.BC#S)q1  
Utility.log(header+" : "+con.getHeaderField(header)); xU`p|(SS-  
else H9e<v4c  
break; \bw2u!  
} <7jW_R@  
} 8bld3p"^  
~b8]H|<'Y  
?$4 PVI}  
public void splitterStop() 9djk[ttA)  
{ -(H0>Ap  
bStop = true; %1+4_g9  
} (SAs-  
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y  
)+9Uoe~6  
} $~T4hv :  
<wD-qTW  
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/* S30%)<W  
**FileAccess.java 0<@@?G  
*//文件访问(定位，写) (n_/`dP  
package NetFox; 'TB2:W3
 
import java.io.*; _X x/(.O  
&Au@S$ij  
}k.Z~1y  
public class FileAccessI implements Serializable{ ncT&G
r  
'6%2.[o  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `e}B2;$A3  
RandomAccessFile oSavedFile; K]w'&Qm8W  
long nPos; "3Y0`&:D  
ey$&;1x#5  
ab?aQ*$+  
public FileAccessI() throws IOException LZxNAua  
{ 4BpZJ~(p  
this("",0); 7HYwLG:\~  
} @f3E`8  
+v:SM9  
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public FileAccessI(String sName,long nPos) throws IOException R.<g3"Lm>  
{ {E|$8)58i  
oSavedFile = new RandomAccessFile(sName,"rw"); e$Pj.>-<=  
this.nPos = nPos; mQ"-,mMI  
oSavedFile.seek(nPos); pOoEI+t  
} DZtsy!xA  
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a0H+.W+]  
public synchronized int write(byte[] b,int nStart,int nLen) 67FWa  
{ 7WzxA=*#  
int n = -1; )zDCu`  
try{ 4;2uW#dG"  
oSavedFile.write(b,nStart,nLen); FGBbO\</  
n = nLen; Yrq~5)%  
} >Cq<@$I2EB  
catch(IOException e) mj7#&r,1l  
{ 5*u+q2\F  
e.printStackTrace (); =>~:<X.,  
} E|shs=I  
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return n; j8:\%|  
} J\=*#*rJ1  
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} S)"Jf?  
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{
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/* k)TpnH! "  
**SiteInfoBean.java XfIJ4ZM5  
*/ LCV(,lu  
package NetFox; B/Ws_Kv  
deh*Ib:(S  
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public class SiteInfoBean { S~G]~gt  
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jT;;/Fd3/  
private String sSiteURL; //Site's URL n|yO9:Uw<  
private String sFilePath; //Saved File's Path QIFgQ0{  
private String sFileName; //Saved File's Name .O<obq~;C  
private int nSplitter; //Count of Splited Downloading File -jmY)(\  
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mc  
public SiteInfoBean() !C.4<?*|  
{//nSplitter的缺省值为5 sU^1wB Rj  
//default value of nSplitter is 5 Pr C{'XDlU  
this("","","",5); a(ZcmYzXU  
} {Qj~M<@3  
=:U`k0rn!  
+:/%3}
`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :7;@ZEe  
{ as=fCuJ  
sSiteURL= sURL; %^6F_F_jS  
sFilePath = sPath; +Vdpy(  
sFileName = sName; _7y[B&g[r  
this.nSplitter = nSpiltter; S$-7SEkO+  
KwVbbC3  
t"I77aZ$A  
} 8
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*|HY>U.  
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public String getSSiteURL() lH~[f  
{ *lJxH8\  
return sSiteURL; J]r^W)O  
} m.0*NW  
u:  
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public void setSSiteURL(String value) z\4.Gm-  
{ ;q>ah!"k  
sSiteURL = value; o^wqFX(Y  
} <wHP2|<l*  
}Ou}+^Bc  
+LJ73 !  
public String getSFilePath() u)Whr@m  
{ "d}Gp9+$VY  
return sFilePath; GTxk%   
} MiX43Pk]  
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;mi%F3  
public void setSFilePath(String value) *qpSXmOz  
{ M)(DZ}  
sFilePath = value; oxtay7fx  
} F((4U"   
_)iCa3z  
/B
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public String getSFileName() 3PF_H$`oJ  
{ (**oRwr%  
return sFileName; (^>J&[=  
} B`sAk %  
?gXp*>Kg[  
a,o*=r  
public void setSFileName(String value) pTuS*MYz  
{ QTnP'5y  
sFileName = value; ksm~<;td  
} ,`sv1xwd  
I( Mm?9F  
yWf`rF{  
public int getNSplitter() zKK9r~ M  
{ HK%7g  
return nSplitter; l%=;  
} MpOc  
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l}P=/#</T  
public void setNSplitter(int nCount) |1Z)E+q*:  
{ 9jGu}Vo  
nSplitter = nCount; /zox$p$?h  
} EiaW1Cs  
} wdoR
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qxJ\ye+'*  
dD@(z:5M\  
/* J9 I:Q<;  
**Utility.java (w zQ2Dk  
*/ ?r!o~|9|  
package NetFox; [<TrS/,)>  
"EJ~QCW*Yh  
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public class Utility { R^e'}+Z  
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&,)&%Sg[  
public Utility() IvNT6]6 P  
{ iJ|uvPCE  
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} fd9k?,zM  
$NO&YLS@  
//线程睡眠 [KQ6Ta.  
public static void sleep(int nSecond) rW#T vUn  
{ Zgb!E]V[
 
try{ N)Z?Z+}h  
Thread.sleep(nSecond); L4l!96]a  
} #|``ca54B  
catch(Exception e) bQ5\ ]5M  
{ Ht&YC<X  
e.printStackTrace (); -%4,@ x`  
} @[v~y"tE}  
} -DAlRz#d,  
9Gz=lc[!7  
//日志 =?`c=z3~i$  
public static void log(String sMsg) 9MqGIOQ${j  
{ 8a"%0d#  
System.err.println(sMsg); xe$_aBU  
} a-J.B.A$Z/  
Yz93'HDB  
-D~%|).
'  
public static void log(int sMsg) |vzl. ^"-  
{
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System.err.println(sMsg); lk80#( :Z  
} e@YK@?^#N  
}
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/* Ef{Vp;]  
**TestMethod.java UR5`ue ;  
*/ ;xn0;V'=  
package NetFox; J4U1t2@)9  
2I{"XB  
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public class TestMethod { mB)bcuPv  
1m0c|ckb  
Z<{QaY$"  
public TestMethod() dUdT7ixo  
{ ///xx/weblogic60b2_win.exe 5Jnlz@P9  
try{ E&:,oG2M  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); I1&aM}y{G  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); MnW+25=N  
SiteFileFetch fileFetch = new SiteFileFetch(bean); k$}fWR  
fileFetch.start(); #A8sLkY  
} *}W_+qo"  
catch(Exception e){e.printStackTrace ();} 8*a&Jl  

""
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Yu2Bkq+  
} Ny)X+2Ae  
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public static void main(String[] args) jb!i$/%w  
{ ZqO^f*F>h  
new TestMethod(); 18:%~>.!  
} 0+b1vhQ  
} FHI ;)wn=  
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