http断点续传简单实现（java)

/* _q([k_4h  
**SiteFileFetch.java UXB[3SP  
*/ e=t?mDh#E  
package NetFox; C~M~2@Iori  
import java.io.*; AR\?bB~`c  
import java.net.*; LX<c(i  
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public class SiteFileFetch extends Thread { g0.D36  
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SiteInfoBean siteInfoBean = null; //文件信息Bean F<q3{}1zR  
long[] nStartPos; //开始位置 SEY  
long[] nEndPos; //结束位置 t/cjz/]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (sw1HR  
long nFileLength; //文件长度 \\jB@O  
boolean bFirst = true; //是否第一次取文件 NF=FbvNe  
boolean bStop = false; //停止标志 /p') u3  
File tmpFile; //文件下载的临时信息 n<:
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DataOutputStream output; //输出到文件的输出流 zx\N^R;Jq  
|7Z,z0 ?V  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） >vg!<%]W]  
public SiteFileFetch(SiteInfoBean bean) throws IOException 9/w'4bd  
{ YgaJ*%\  
siteInfoBean = bean; Co8b0-Z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3OHP-oa.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9frx
60  
if(tmpFile.exists ()) r @~T}<I  
{ -"5x? \.{m  
bFirst = false; o}5:vi
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read_nPos(); Yfy6o6*:  
} $4kc i@.  
else XKp%
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{ yz-IZt(  
nStartPos = new long[bean.getNSplitter()]; sZ-]yr\E"  
nEndPos = new long[bean.getNSplitter()]; uVqJl{e\  
} ovCk:Vz  
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} uqZLlP#&#  
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public void run() 8aGZ% UI  
{ MAR kTxzi  
//获得文件长度 l1c&a[M)  
//分割文件 ,$3  
//实例FileSplitterFetch
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//启动FileSplitterFetch线程 tZ[BfO  
//等待子线程返回 [p@NzS/  
try{ 4:cbasy  
if(bFirst) mU_?}}aK,  
{ M@Q=!!tQ(  
nFileLength = getFileSize(); UA,&0.7  
if(nFileLength == -1) MCQ>BP  
{ lf|e8kU\f  
System.err.println("File Length is not known!"); U6X
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} xpyb&A  
else if(nFileLength == -2) *NV`6?o@6  
{ K_`*ZV{r  
System.err.println("File is not access!"); )F? 57eh  
} P0Na<)\'Y!  
else !N,Z3p>
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{ 5 LX3.  
for(int i=0;i<nStartPos.length;i++) z$G?J+?J  
{ p%IR4f  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >^:g[6Sj  
} nAF@47Wo  
for(int i=0;i<nEndPos.length-1;i++) v\-"NHl  
{ C?rL>_+71  
nEndPos = nStartPos[i+1]; '*>LZo4  
} t
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nEndPos[nEndPos.length-1] = nFileLength; 7OtQK`P"A
 
} `P/*x[?  
} U`6QD}c"s  
G !1- 20  
f'
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//启动子线程 V@>?lv(\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; NJUYeim;  
for(int i=0;i<nStartPos.length;i++) -f9M*7O<gf  
{ K?[pCF2C  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [tMf KO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), + y.IDn^  
nStartPos,nEndPos,i); ,_rarU)[
J  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =La}^  
fileSplitterFetch.start(); 9b]U&A$  
} eiEZtu  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F:pXdU-xf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6xL=JSi~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0y;&L63>T  
nEndPos = " + nFileLength); #j-,#P@  
// fileSplitterFetch[nPos.length-1].start(); g#[9O'H  
`8FC&%X_  
]Jnf.3  
//等待子线程结束 .?I!/;=[  
//int count = 0; iZMsN*9[  
//是否结束while循环 #-'}r}1ZT  
boolean breakWhile = false; |B`-chK  
]Vb#
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while(!bStop) .yTk/x?  
{ sF+0v p  
write_nPos(); IJ4"X#Q/  
Utility.sleep(500); %-A8`lf<  
breakWhile = true; Z$zUy|s[  
$elrX-(vL  
Z
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for(int i=0;i<nStartPos.length;i++) B10p7+NBF  
{ ePs<jrB<  
if(!fileSplitterFetch.bDownOver) +ypG<VBx%  
{ \=N tbBL$[  
breakWhile = false; SOK2{xCG  
break; {6%uNT>|  
} >t D-kzN  
} K,IOD t  
if(breakWhile) N7oMtlvL[w  
break; !5B9:p~-  
G4x.''r&Sl  
pK'WJ 72U  
//count++; EW5S%Y  
//if(count>4) Z$ftG7;P0  
// siteStop(); ^7"%eWT`  
} raqLXO!j  
3$Is==>7  
21o_9=[^  
System.err.println("文件下载结束！"); MxdfuFss  
} v,D_^?]@  
catch(Exception e){e.printStackTrace ();} y5Pw*?kn  
} gE ,j\M*  
h5f>'l
z  
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//获得文件长度 l4/TJ%`MG  
public long getFileSize() `|/|ej]$P  
{ ESomw  
int nFileLength = -1; 5z]dA~;*2  
try{ 'nT#3/rL  
URL url = new URL(siteInfoBean.getSSiteURL()); o[v`Am?v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .\d0lJSr  
httpConnection.setRequestProperty("User-Agent","NetFox"); |iwTzlt*#  
g$ 2M|Q  
.R gfP'M  
int responseCode=httpConnection.getResponseCode(); Iyc')\W&  
if(responseCode>=400) mefmoZ  
{ i;xg[e8.  
processErrorCode(responseCode);  Nl_;l  
return -2; //-2 represent access is error j}VOr >xz  
} |wLQ)y*  
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String sHeader; :jUuw:\  
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for(int i=1;;i++) 0l:5hD,)F  
{ eXOFAd]>u  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); X~DXx/9  
//Utility.log(in.readLine()); P9>C!0 -x  
sHeader=httpConnection.getHeaderFieldKey(i); 6AwnmGL(;;  
if(sHeader!=null) w-#0k.T  
{ H9>&"=".  
if(sHeader.equals("Content-Length")) AN%.LK  
{ 2ga}d5lu  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); RyhR#  
break; xg^fM@#m  
} N|~&Q!A&  
} k9
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else \6'A^cE/PX  
break; ib&qH_r/  
} xaS  
} v'>Yc#VJ  
catch(IOException e){e.printStackTrace ();} E, v1F!  
catch(Exception e){e.printStackTrace ();} p!a%*LfND  
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Utility.log(nFileLength); c:6w >:  
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return nFileLength; 9@1W=sl  
} ~>C>LH>8  
*Qf}4a0  
zh.c_>jS  
//保存下载信息（文件指针位置） IW1\vfe  
private void write_nPos() QVH_B+ Q  
{ b5|p#&YK~  
try{ < 5PeI  
output = new DataOutputStream(new FileOutputStream(tmpFile)); )aC+qhh  
output.writeInt(nStartPos.length); i3"sArP"|  
for(int i=0;i<nStartPos.length;i++)
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{ /iN\)y#u1  
// output.writeLong(nPos); sXa8(xc  
output.writeLong(fileSplitterFetch.nStartPos); 64vSJx>u  
output.writeLong(fileSplitterFetch.nEndPos); [>:gwl _\  
} 8$vH&HdI  
output.close(); 3?XLHMxW  
} e||_j  
catch(IOException e){e.printStackTrace ();} &\H5*A.HkA  
catch(Exception e){e.printStackTrace ();} ]03ZrZ! PM  
} /t
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h+W^k+~(  
bS'r}  
//读取保存的下载信息（文件指针位置） )q^vitkjup  
private void read_nPos() xY S%dLE"  
{ YXtGuO\q  
try{ d<Os TA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !LJ.L?9qw  
int nCount = input.readInt(); J50 ~B3bj`  
nStartPos = new long[nCount]; +)@>60y  
nEndPos = new long[nCount]; 9y5\4&v  
for(int i=0;i<nStartPos.length;i++) XZInu5(  
{ 2T5xSpC  
nStartPos = input.readLong(); +i^s\c!3;  
nEndPos = input.readLong(); gAj)3T@  
} wuk7mIJ  
input.close(); 9CNHjs+-}s  
} K_5&_P1  
catch(IOException e){e.printStackTrace ();} @5y(>>C}8%  
catch(Exception e){e.printStackTrace ();}
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} `Ek!;u>  
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private void processErrorCode(int nErrorCode) y]l"u=$Tr{  
{ ;Kf|a}m-  
System.err.println("Error Code : " + nErrorCode); %RN-J*s]  
} ay_D.gxz  
#H
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_PM<25Y,@  
//停止文件下载 [&CM-` N  
public void siteStop() a
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{ hwzUCh 5!  
bStop = true; W/>?1+r.Z  
for(int i=0;i<nStartPos.length;i++) iy]}1((hR  
fileSplitterFetch.splitterStop(); [hL1PWKs  
!I[n|r"  
7fay:_  
} 32iI :u  
} JF*g!sV%  
//负责部分文件的抓取 f}X8|GlBo  
**FileSplitterFetch.java m-89nOls  
*/ 6p"c^  
package NetFox; xp&!Cl>C3\  
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mr!I}I7x&x  
import java.io.*; \.c )^QQ  
import java.net.*; Hg`{9v  
V]]qu:Mh8  
|T_Pz&-  
public class FileSplitterFetch extends Thread { b8.%?_?  
YfwJBzD  
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String sURL; //File URL pK9^WT@  
long nStartPos; //File Snippet Start Position 2?T:RB}  
long nEndPos; //File Snippet End Position z#VpS=  
int nThreadID; //Thread's ID  +Rgw
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boolean bDownOver = false; //Downing is over )$B+3f  
boolean bStop = false; //Stop identical !Blk=L+p  
FileAccessI fileAccessI = null; //File Access interface ^\&g
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;a&:r7]=  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (AG  
{ r^t{Ii~  
this.sURL = sURL; DME?kh>7  
this.nStartPos = nStart; X-1Vp_(,TP  
this.nEndPos = nEnd; Z9&
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nThreadID = id; c@-K  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Zd U{`>v  
} DBBBpb~~  
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1=Zw=ufqV  
public void run() aT!9W'uY  
{ ?=!XhU .  
while(nStartPos < nEndPos && !bStop) aNC,ccm  
{ :bRR(sP  
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try{ +.]}f}Y  
URL url = new URL(sURL); b8Rh|"J)
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); : W^\ mH
 
httpConnection.setRequestProperty("User-Agent","NetFox"); J7ekIQgR  
String sProperty = "bytes="+nStartPos+"-"; 5u_4lNJ&  
httpConnection.setRequestProperty("RANGE",sProperty); Gd-.E7CH!  
Utility.log(sProperty); RLz`aBT  
ZQ9oZHUm  
6b]d|  
InputStream input = httpConnection.getInputStream(); h ^h-pd  
//logResponseHead(httpConnection); GR ?u?-  
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byte[] b = new byte[1024]; ;Uqx&5P}  
int nRead; "qTC(F9N$.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q 95
 
{ P%`R7yk  
nStartPos += fileAccessI.write(b,0,nRead); \678Nx  
//if(nThreadID == 1) e( o/we{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R96o8#7Uv  
} IR dz(~CP  
z8(R.TB  
y)/$ge_U  
Utility.log("Thread " + nThreadID + " is over!"); };m7FO  
bDownOver = true; Ui|a}`c  
//nPos = fileAccessI.write (b,0,nRead); Z;y}gv/{  
} As'M39*V  
catch(Exception e){e.printStackTrace ();} ^T&u!{82j  
} Z!-<ra
jl  
} gZ"{{#:}  
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//打印回应的头信息 BgWz<k}5M  
public void logResponseHead(HttpURLConnection con) e#6&uFce  
{ 5uV"g5?w  
for(int i=1;;i++) vvsNWA
 
{ <`xRqe:&9  
String header=con.getHeaderFieldKey(i); aY[0A_  
if(header!=null) :gD0EqV  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); k<'vP{  
Utility.log(header+" : "+con.getHeaderField(header)); ^s@*ISY  
else :uwRuPI  
break; mrhp)yF  
} @oz&  
} 22/?JWL>  
9j?hF$L"  
bj7MzlGFy  
public void splitterStop() ]EM)_:tRf  
{ +:"6`um|  
bStop = true; {1@4}R4  
} 32 1={\X  
2Ph7qEBQ22  
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} KBr5bcm4u  
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9O=05CQ  
/* o?va#/fk  
**FileAccess.java CS;W)F  
*//文件访问(定位，写) hdf8U  
package NetFox; A:.IBctsd  
import java.io.*; YoF\MT]W  
1>@]@ST[:  
gl9pgY1ni  
public class FileAccessI implements Serializable{ LN.Bd,  
 bL'#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4VmCW"b7h  
RandomAccessFile oSavedFile; )"_Ff,9Z!  
long nPos; #U$YZ#B  
X&9^&U=e  
b>bgUDq  
public FileAccessI() throws IOException uq|vNLW26  
{ Lov.E3S6;  
this("",0); 3%[)!zKv  
} z[5Y Z~}*  
[/AdeR  
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public FileAccessI(String sName,long nPos) throws IOException Pu$kj"|q*[  
{ *CH!<VB/  
oSavedFile = new RandomAccessFile(sName,"rw"); qP;{3FSkAF  
this.nPos = nPos; o0aO0Y  
oSavedFile.seek(nPos); *X=@yB*aK  
} L,L~ .E  
r;cI}'  
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public synchronized int write(byte[] b,int nStart,int nLen) )e|$K= D  
{ Q$?7)yyu+  
int n = -1; 7cUR.PI#Q  
try{ %UUp=I  
oSavedFile.write(b,nStart,nLen); Ok}{jwJ%W;  
n = nLen; o\@ A2r3  
} agU%z:M{  
catch(IOException e) ,#E3,bu6_4  
{ :$M9XZ~\  
e.printStackTrace (); V6@*\+:3)  
} DMAf^.,S  
6z9R1&~%  
;}n9yci#  
return n; u#41osUVW>  
} Uh3wj|0  
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} %w'/n>]j  
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~t{D5#LVHa  
/* ;g: UE  
**SiteInfoBean.java l~]hGLviJE  
*/ [Krm .)  
package NetFox; t4f (Y,v  
zB#_:(1qK  
LyuSZa]  
public class SiteInfoBean { MekT?KPQ{L  
6CcB-@n4  
'[>\N4WD  
private String sSiteURL; //Site's URL 0kU3my]  
private String sFilePath; //Saved File's Path o,S!RG&  
private String sFileName; //Saved File's Name !dfS|BA]  
private int nSplitter; //Count of Splited Downloading File !Qv5"_  
yxaT7Oqh%  
<X:Ud&\  
public SiteInfoBean() E fP>O  
{//nSplitter的缺省值为5 9GMH*=3[=  
//default value of nSplitter is 5 hH<6E  
this("","","",5); 94~"U5oQ:  
} 4*0:bhhhf_  
"XGD:>Q.  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) TpJg-F  
{ Zg)_cRR   
sSiteURL= sURL; snXB`UC  
sFilePath = sPath; 5z1\#" B[  
sFileName = sName; ~
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this.nSplitter = nSpiltter; D ?Nd;[  
- *:p.(c  
>
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} WW//heJe-  
[3t0M5x w  

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public String getSSiteURL() '8s>rH5[V  
{ 0zg2g!lh  
return sSiteURL; XMt u"K  
} !OPSSP]-  
,9=gVW{  
>%9^%p^  
public void setSSiteURL(String value) 8K|J:[7  
{ lbQ6 a  
sSiteURL = value; AI&qU/}  
} \bU`  
Qo'yS"g<9)  
! G*&4V3Mg  
public String getSFilePath() c*N50%=4  
{ x1t{SQ-C  
return sFilePath; !cRfZ  
} mbF(tSy  
rei 8LW  
dX_!0E[c  
public void setSFilePath(String value) Wt>J`  
{ J"diFz+20  
sFilePath = value; fx<FIj7  
} sB?2*S"X)<  
8$\Za,)g  
6tOCZ'f  
public String getSFileName() ?Fce!J  
{ RTK}mhnV  
return sFileName; inYM+o!Ub  
} i][f#e4  
F4GP7]  
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public void setSFileName(String value) `&7mHa61  
{ #":: '?,  
sFileName = value; fi=0{  
} DeH0k[o  
^uia`sOP4  
a*D,*C5}  
public int getNSplitter() v9u<F6  
{ ERF,tLa!  
return nSplitter; !6M Bxg>  
} ar Q)%W  
%Nj #0YF]  
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public void setNSplitter(int nCount) BU!#z(vU  
{ J5;5-:N  
nSplitter = nCount; ndr)3tuYu  
} s8^~NX(xdy  
} 88 {1mA,v  
fO6[!M(  

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/* tmp6hB  
**Utility.java eI^gV'UK  
*/ cA<<&C  
package NetFox; !K[/L< Kv  
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public class Utility { 80|onP
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public Utility()
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{ :/6()_>bO  
s _~IZ%+<.  
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} ur6e&bTp  
#,&8&  
//线程睡眠 GzdRG^vN  
public static void sleep(int nSecond) _%{0?|=  
{ %%&e"&7HE  
try{ oE1M/*myS  
Thread.sleep(nSecond); {SJsA)9:#  
} )B;M  
catch(Exception e) +oZH?N4yaM  
{ b0 &  
e.printStackTrace (); +Qs!Nhsq  
} C`NmZ
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} =p q:m  
DVh)w}v  
//日志 <4c%Q)  
public static void log(String sMsg) pA.._8(t  
{ qp>N^)>
 
System.err.println(sMsg); -(9O6)Rs$  
} 7Lg7ei2mN7  
n?:2.S.8  
]v\^&7pW  
public static void log(int sMsg) ;'}'5nO=$  
{ !"E-\cc'  
System.err.println(sMsg); (9]6bd  
} zT7"VbP  
} F.?01,J=1  
b/u8} J  
J=iRul^S  
/* 89Z#|#uM5  
**TestMethod.java (rcMA>2=  
*/ 2 z7}+lH  
package NetFox; u]E.iXp  
t`YWwI.  
=u=Kw R  
public class TestMethod { qnJ50 VVW  

Uyk,.*8"  
BSgTde|3y  
public TestMethod() $mpO?D J~  
{ ///xx/weblogic60b2_win.exe ^I`a;  
try{ Blk}I  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 'J
ydu   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zTY;8r+  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
E!! alc{  
fileFetch.start(); jO8X:j09A  
} 8KMvAc  
catch(Exception e){e.printStackTrace ();} ETfF5i}  
<6jFKA<  
CZ(`|;BC*  
} k!3 cq)  
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public static void main(String[] args) 0Z HDBh  
{ Vb!O8xV4;+  
new TestMethod(); \uM? S  
} fu R2S70d  
} I]R9HGJNlJ  
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