http断点续传简单实现（java)

/* hza> jR  
**SiteFileFetch.java Jcz]J)|5v  
*/ )sW6iR&_i  
package NetFox; [DZqCo  
import java.io.*; Y=vVxVI\  
import java.net.*; R:'Ou:Mh  
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q=6Cc9FN  
public class SiteFileFetch extends Thread { Xhcn]  
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SiteInfoBean siteInfoBean = null; //文件信息Bean iq"ob8.  
long[] nStartPos; //开始位置 R
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long[] nEndPos; //结束位置 3CR@' qG-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 /?KtXV>]  
long nFileLength; //文件长度 I|,pE**T  
boolean bFirst = true; //是否第一次取文件 M1oPOC\0.  
boolean bStop = false; //停止标志 Bo`Tl1K#  
File tmpFile; //文件下载的临时信息 d<Ggw#}:m  
DataOutputStream output; //输出到文件的输出流 ?y~TCqV  
#`W=mN(+k  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） @j O4EEe:  
public SiteFileFetch(SiteInfoBean bean) throws IOException {<qF}i:V  
{ V0K16#}1gM  
siteInfoBean = bean; 25 CZmsg  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +I t#Z3  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %*wzO9w4  
if(tmpFile.exists ()) *YWk1Cwjo  
{ !fY7"E{%%  
bFirst = false; 2w+U$6e C  
read_nPos(); )Im3'0l>  
} NJtQx2Sd'H  
else lDN"atSf  
{ |]`hXr  
nStartPos = new long[bean.getNSplitter()]; *LANGQ"2(i  
nEndPos = new long[bean.getNSplitter()]; >F1G!#$0  
} HBH$  
=#qZ3 Qz_  
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} HPg3`Ul  
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x
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public void run() >M]6uf  
{ {C3U6kKs;R  
//获得文件长度 bu>qsU3  
//分割文件 7BR8/4gcPu  
//实例FileSplitterFetch eG5Y+iL-V  
//启动FileSplitterFetch线程 *U;'OWE[  
//等待子线程返回 'Gx$Bj  
try{ jjRUL.  
if(bFirst) X'f.Q  
{ UiH!Dl}<  
nFileLength = getFileSize(); "13"`!m  
if(nFileLength == -1) +Y}V3(w9X  
{ 5G(3vRX|1  
System.err.println("File Length is not known!"); 7FLXx?nLY  
} W+Xz$j/u  
else if(nFileLength == -2) {%C*{,#+8q  
{ {`(>O"_[Q  
System.err.println("File is not access!");  8"%RCE  
} M*sR3SZ  
else u7fK1
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{ w]u@G-e  
for(int i=0;i<nStartPos.length;i++) nOb?-rR  
{ ?^i1_v7 Bi  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ljC(L/I  
} :u6JjW[a)  
for(int i=0;i<nEndPos.length-1;i++) z0%\OhuCcf  
{ \(~wZd  
nEndPos = nStartPos[i+1]; r@U3sO#N  
} hB9Ee@  
nEndPos[nEndPos.length-1] = nFileLength; ujFzJdp3k  
} 8j5<6Cv_  
} !}f1`/   
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7%MbhlN.  
//启动子线程 <IJu7t>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; l[Q:}y  
for(int i=0;i<nStartPos.length;i++) ~g#r6pzN-  
{ $P z`
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OFk8>"|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 6E~g#(8  
nStartPos,nEndPos,i); omSM:f_~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5|QzU|gPn  
fileSplitterFetch.start(); H 3@Z.D  
} B9R(&<4  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0(U#)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6$U]9D  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", q:\g^_!OGA  
nEndPos = " + nFileLength); 2P#=a?~[  
// fileSplitterFetch[nPos.length-1].start(); O.`Jl%  
;U9J++\d<A  
VU`OO$,W  
//等待子线程结束 Z@a9mFI?  
//int count = 0; 'e)^m}:?D  
//是否结束while循环 lot%N(mB`  
boolean breakWhile = false; \Ig68dFf%  
&;yH@@Z  
IW=cym7  
while(!bStop) /cc\fw1+  
{ ^C2\`jLMY  
write_nPos(); xsWur(>]  
Utility.sleep(500); C9p"?vX  
breakWhile = true; \u6^Varw  
'_|h6<.k[  
9UvXC)R1  
for(int i=0;i<nStartPos.length;i++) ~]ZpA-*@Ut  
{ %Uz(Vd
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if(!fileSplitterFetch.bDownOver) 2^?:&1:  
{ f/CuE%7BR  
breakWhile = false; CI3XzH\IX*  
break; }9nDo*A"}  
} N},n `Yl.  
} K~ ;45Z2  
if(breakWhile) (b`]M`Fc  
break; B]tIi^  
lJ@][;  
g-Pwp[!qkf  
//count++; aZ\UrV4,  
//if(count>4) II
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// siteStop(); `a9L%z  
} #s!'+|2n  
|!y A@y?  
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System.err.println("文件下载结束！"); fxgr`nC  
} %#$EP7"J  
catch(Exception e){e.printStackTrace ();} V2N_8)s9W  
} OgX6'E\E  
$0arz{Oh  
TRsE %  
//获得文件长度 L\;6y*K  
public long getFileSize() vVL@K,q  
{ xU%w=0z<  
int nFileLength = -1; g[w,!F  
try{ 3"rzb]=R  
URL url = new URL(siteInfoBean.getSSiteURL()); u :F~K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); KoS*0U<g6  
httpConnection.setRequestProperty("User-Agent","NetFox"); n`4K4y%Dy}  
;[a|9T
PR  
*28pRvY:b  
int responseCode=httpConnection.getResponseCode(); `c'W-O/  
if(responseCode>=400) c2K:FdB  
{ `%j~|i
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processErrorCode(responseCode); IJ/sX_k  
return -2; //-2 represent access is error b"TjGE  
} BATG FS&  
J/3_C6U
Z  
6)BR+U  
String sHeader; w4fW<ISg  
b=/curl&  
++DG5`  
for(int i=1;;i++) pFJB'=c  
{ n#iwb0-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); x
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//Utility.log(in.readLine()); asC_$tsMe  
sHeader=httpConnection.getHeaderFieldKey(i); sCu+Lg~f  
if(sHeader!=null) JCW\ *R  
{ O2"gj"D  
if(sHeader.equals("Content-Length")) r/*=%~*  
{ xai4pF-?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5 QO34t2  
break; Yf[Qtmh]I  
} Dwl3Cj  
} 5pn)yk~  
else ^H6<Km l/V  
break; BT@r!>Nl  
} &Ni`e<mP  
} q
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catch(IOException e){e.printStackTrace ();} G-T0f  
catch(Exception e){e.printStackTrace ();} w/L `  
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Utility.log(nFileLength); U#1bp}y  
3 LdQ]S  
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return nFileLength; wYlf^~#
"  
} HQ{JwW!m  
sp*Vqd  
1 tR_8lC  
//保存下载信息（文件指针位置） CwX Z  
private void write_nPos() 46k?b|Q  
{ w4LScvBg  
try{ *~/OOH$"  
output = new DataOutputStream(new FileOutputStream(tmpFile));  RDtU43  
output.writeInt(nStartPos.length); 0dh=fcb  
for(int i=0;i<nStartPos.length;i++) ZR\VCVH\^  
{ [2|kl l  
// output.writeLong(nPos); @2*]"/)*0  
output.writeLong(fileSplitterFetch.nStartPos); |!F5.%PY  
output.writeLong(fileSplitterFetch.nEndPos); =
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} X<R?uI?L  
output.close(); #Eb5:;  
} ",)Qc!^P$  
catch(IOException e){e.printStackTrace ();} 2[gFkyqe  
catch(Exception e){e.printStackTrace ();} {3!E4"p
 
} |7#[ (%D!  
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//读取保存的下载信息（文件指针位置） {hJXj,  
private void read_nPos() &[&r2>a  
{ sN("+ sZ.n  
try{ |X`/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 3~#h|?  
int nCount = input.readInt(); CB&iI'  
nStartPos = new long[nCount]; +1~Z#^{&  
nEndPos = new long[nCount]; <x\7L2#p  
for(int i=0;i<nStartPos.length;i++) @x/T&67k  
{ XW?b\!@ $  
nStartPos = input.readLong(); Skz|*n|eY  
nEndPos = input.readLong(); .%zy`n  
} %_
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input.close(); $3,ryXp7  
} kPjd_8z2n  
catch(IOException e){e.printStackTrace ();} hd 0'u  
catch(Exception e){e.printStackTrace ();} 45&8weXO:'  
} +w8R!jdA  
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private void processErrorCode(int nErrorCode) IHp_A  
{ ip~$X2  
System.err.println("Error Code : " + nErrorCode); StI1){Wf  
} K 0hu:1l)  
Bb{!Yh].:A  
1&:@  
//停止文件下载 +\"-P72vjk  
public void siteStop() mQ}ny(K'  
{ Eq:2k)BE  
bStop = true; hAj1{pA,  
for(int i=0;i<nStartPos.length;i++) i*eAdIi  
fileSplitterFetch.splitterStop(); ,^8MB.  
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} ^h&I H|  
} %c)[ kAU!  
//负责部分文件的抓取 ~m*,mz  
**FileSplitterFetch.java MlW 8t[  
*/
:D7|%KK  
package NetFox; Z2"?&pKV  
[i]r-|_K  
3/JyUh?  
import java.io.*; iK{T^vvk  
import java.net.*; -6sW6;Q  
@DC)]C2  
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public class FileSplitterFetch extends Thread { H6aM&r9}  
A-CUv[pM  
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String sURL; //File URL /XS&d%y  
long nStartPos; //File Snippet Start Position m=qOg>k  
long nEndPos; //File Snippet End Position <5@PWrU?[[  
int nThreadID; //Thread's ID _~aG|mAj
 
boolean bDownOver = false; //Downing is over buk=p-oi  
boolean bStop = false; //Stop identical 2=ztKfsBhE  
FileAccessI fileAccessI = null; //File Access interface A>.2OC+  
f=J<*h  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException j[6Raf/(n  
{ g<\z=H  
this.sURL = sURL; ^;F{)bmu+)  
this.nStartPos = nStart; #t!}K_  
this.nEndPos = nEnd; 7 gB{In0  
nThreadID = id; v[<Bjs\q5  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1@XgTL4  
} )y7_qxwbV  
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public void run() rn.\tDeA  
{ TOI4?D]  
while(nStartPos < nEndPos && !bStop) h7qBp300  
{ DlE_W+F  
bdh(WJh%  
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try{ k5+]SG`]]  
URL url = new URL(sURL); N~,_`=yRx  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,yLw$-  
httpConnection.setRequestProperty("User-Agent","NetFox"); -+U/Lrt>8  
String sProperty = "bytes="+nStartPos+"-"; Uedvc5><t  
httpConnection.setRequestProperty("RANGE",sProperty); ST8!i`Q$  
Utility.log(sProperty); 2pyt&'NJua  
0o&}mKe  
L*]E`Xxd9  
InputStream input = httpConnection.getInputStream(); 4f1D*id*`#  
//logResponseHead(httpConnection); B!aK  
?)tK!'  
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byte[] b = new byte[1024]; I^Qx/uTKw  
int nRead; @Hr+/52B  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) QV,E#(\5  
{ iH)Nk^  
nStartPos += fileAccessI.write(b,0,nRead); DacJ,in_I{  
//if(nThreadID == 1) Nh)[rx  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =v"xmx&4  
} 6GOcI#C9C  
F>Y9o-o2  
S6 }
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Utility.log("Thread " + nThreadID + " is over!"); |ViU4&d*  
bDownOver = true; .`LgYW  
//nPos = fileAccessI.write (b,0,nRead); aMCO"66b  
} A'eAu  
catch(Exception e){e.printStackTrace ();} .1ddv4Hk  
} LC
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} ?e
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By)3*<5a_  
Lk(S2$)*  
//打印回应的头信息 ch,|1}bi  
public void logResponseHead(HttpURLConnection con) {fG|_+tl3o  
{ Ku%6$C!,  
for(int i=1;;i++) `Wf5  
{ )W9_qmYd"  
String header=con.getHeaderFieldKey(i); Hcl"T1N*  
if(header!=null) Hhf72IX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @P70W<<  
Utility.log(header+" : "+con.getHeaderField(header)); T]2U fi.  
else W]LQ &f  
break; ^('cbl  
} )q(:eoLDm  
} ]GS~i+=M  
|e"/Mf[  
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public void splitterStop() k|ip?O  
{ T 'i~_R6  
bStop = true; ]piM/v\  
} RO(iHR3cA  
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} QE6E
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/* <rMv0y+r  
**FileAccess.java ZV#$Z  
*//文件访问(定位，写) kC|Tubs(  
package NetFox; E.#6;HHzN  
import java.io.*; O"QHb|j  
{|p"; uJ  
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public class FileAccessI implements Serializable{ 4a 4N C  
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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 AI R{s7N  
RandomAccessFile oSavedFile; >@:667i,`  
long nPos; -XLo0  
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kyK'  
public FileAccessI() throws IOException rkq)&l=ny  
{ vh{9'vd3el  
this("",0); cLHF9B5  
} uwId  
bu&;-Ynb
 
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public FileAccessI(String sName,long nPos) throws IOException y-<$bA[K~  
{ dWjx"7^  
oSavedFile = new RandomAccessFile(sName,"rw"); kI<WvgoL  
this.nPos = nPos; ennR@pg  
oSavedFile.seek(nPos); 'hy?jQ'|e  
} 44Q9*."  
v*vn<nPAQ>  
#_{0Ndp2  
public synchronized int write(byte[] b,int nStart,int nLen) yqYhe-"  
{ :TlAL# s&  
int n = -1; OH0S2?,{>  
try{ }E,jR
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oSavedFile.write(b,nStart,nLen); %`
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n = nLen; [
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} 76$*1jB  
catch(IOException e) -E}>h[;qZ  
{ "*+\KPCU  
e.printStackTrace (); k06xz#pL  
} 6<<'bi  
8.[&wyU  
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return n; )`mbf|,&t{  
} @W#fui<<}Y  
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} 6zv;lx0<D&  
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Q js2hj-$  
/* qFrt^+@  
**SiteInfoBean.java phr2X*Z/)Y  
*/ qQL.c+%L  
package NetFox; I/Sv"X6E  
l<W*/}3  
w2 /* `YO  
public class SiteInfoBean { U@
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*wViH  
 NvUu
.  
private String sSiteURL; //Site's URL #fwzFS \XL  
private String sFilePath; //Saved File's Path `b#/[3  
private String sFileName; //Saved File's Name Y 5Qb4Sa  
private int nSplitter; //Count of Splited Downloading File LE8K)i  
$4DFgvy$  
{5U1`
>  
public SiteInfoBean() ('T4Db  
{//nSplitter的缺省值为5 4g>1Gqv6  
//default value of nSplitter is 5
Tku/OG'  
this("","","",5); ZEL/Ndk  
} C5>{Q:.`e'  
#!w:_T%  
y>@v>S  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;&K3[;a  
{ ?F)_T  
sSiteURL= sURL; CFD*g\g<*  
sFilePath = sPath; EW ~*@H  
sFileName = sName; !O~},pp  
this.nSplitter = nSpiltter; cC b>zI  
#:]vUQ  
DhY;pG,t  
} =ZCH1J5"  
]&&I|K_  
9+]ZH.(YE  
public String getSSiteURL() qRgK_/[]  
{ pZc9q8j3  
return sSiteURL; !8wZw68"  
} )W[KD,0+j  
bs:C1j\&  
hCU)W1q#  
public void setSSiteURL(String value) Sja"(sJ  
{ H%*~l  
sSiteURL = value; 2v"wWap-+  
} &z./4X  
xnl<<}4pJ  
EZ:I$X  
public String getSFilePath() L@C >-F|p  
{ 38"8,k  
return sFilePath; Q'FX:[@x-S  
} y&n1 Nj]^  
3c1o,2  
Zr
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public void setSFilePath(String value) ;yRwoTc)Y  
{ fMWXo)rzj  
sFilePath = value; @qg0u#k5  
} <ol$-1l#9  
Iu=pk@*O  
d_4n0Kh0  
public String getSFileName() e1f^:C  
{ H @3$1h&YS  
return sFileName; 27h/6i3  
} sW>P-  
oN1!>S9m  
pHI%jHHJ  
public void setSFileName(String value) EGQ1li'B  
{ w3>Y7vxiz`  
sFileName = value; &*V0(  
} PO=ZxG
  
#Pe\Z/  
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public int getNSplitter() 
:Olj   
{ 3L 1lq .  
return nSplitter; Apw-7*/  
} ZI#SYEF6  
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public void setNSplitter(int nCount) MkluK=$  
{ (HTk;vbZm  
nSplitter = nCount; xX/Qoq (}i  
} N#2nH1C  
} @=aq&gb  
!0d9<SVC  
+v`^_  
/* tyGnG0GK  
**Utility.java X*p:&=o  
*/ Eo25ir%  
package NetFox; \8C*O{w  
^<5^9]x  
N2S!.H!Wz  
public class Utility { ZT3jxwe  
epY;1,;>  
=t>`<T|(  
public Utility() $48[!QE  
{ 0ghwFo  
@Tj  6!v  
Z?G3d(YT  
} RIVN>G[;L  
.q;RNCUt  
//线程睡眠 Liz6ob  
public static void sleep(int nSecond) ht[TMdV  
{ [/2@=Uh-  
try{ -7A!2mRiz  
Thread.sleep(nSecond); brhJ&|QDE  
} y&O_Jyg<  
catch(Exception e) J4R  
{ ^Qb!k/$3y  
e.printStackTrace (); oVj A$|  
} kY |=a  
} 4j=@}!TBt  
daokiU+l2  
//日志 a1Y_0  
public static void log(String sMsg) 14)kKWG  
{ )8A=yrTIT  
System.err.println(sMsg); zj$Z%|@$  
} f~(^|~ZT  
]a@v)aa-  
OG<]`!"  
public static void log(int sMsg) ?[|4QzR  
{ Y&!McM!Jw  
System.err.println(sMsg); ~'YSVx& )  
} oz5lt4  
} *~aI>7H  
Q,LWZw~"  
J,2v~Dq  
/* {&AT}7  
**TestMethod.java fJ+E46|4  
*/ *{n,4d\..  
package NetFox; Y~\xWYR  
 x+j/v5  
#cg@Z  
public class TestMethod { <PA$hTYM  
Y&Nv>o_}5  
Lm2cW$s  
public TestMethod() gM/_:+bT>P  
{ ///xx/weblogic60b2_win.exe IaZAP  
try{ UgBY ){<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); u=N;P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \$++.%0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 4w  
fileFetch.start(); ,PtR^" Mf4  
} ="*C&wB^  
catch(Exception e){e.printStackTrace ();} TOP'Bmb  
=$`")3y3  
$TUC?e9"h  
} {:!SH6 ff  
!Kn+*'#  
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public static void main(String[] args) Y+PxV*"a  
{ 7VD7di=D  
new TestMethod(); 60gn`s,,  
} 5 BG&r*U  
} I(eR3d:  
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