http断点续传简单实现（java)

/* [*Z;\5&P  
**SiteFileFetch.java &)Q
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*/ =O~_Q-  
package NetFox; em
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import java.io.*; bTI|F]^!  
import java.net.*; ?>VLTp8]  
dB{Q"!
 
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public class SiteFileFetch extends Thread { !Lu2  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 8=!D$t\3  
long[] nStartPos; //开始位置 ?al'F q  
long[] nEndPos; //结束位置 A[B<~  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 &5>Kl}7  
long nFileLength; //文件长度 !hm]fh_j  
boolean bFirst = true; //是否第一次取文件 y#`tgJ:  
boolean bStop = false; //停止标志 qv-8)MSr  
File tmpFile; //文件下载的临时信息 m&d|t>3<  
DataOutputStream output; //输出到文件的输出流 @="Pn5<]C  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）  \__i  
public SiteFileFetch(SiteInfoBean bean) throws IOException aEB_#1  
{ <;lkUU(WT2  
siteInfoBean = bean; Jx:Y-$  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %7hrk  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q9B$"n  
if(tmpFile.exists ()) Lw1Yvtn  
{ HVRZ[Y<^  
bFirst = false; Ao 'l"-  
read_nPos(); -uS!\  
} &0d#Y]D4`  
else \$K20)  
{ ;[ZEDF5H  
nStartPos = new long[bean.getNSplitter()]; IW5,
7.  
nEndPos = new long[bean.getNSplitter()]; ,CJWO bn3  
} KR}?H#%  
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} aj='b.2)  
,~U>'&M;  
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public void run() 2Ah#<k-gC;  
{ 2DA]i5  
//获得文件长度 `bq
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//分割文件 g&L!1<, p  
//实例FileSplitterFetch [g|_~h  
//启动FileSplitterFetch线程 r `=I  
//等待子线程返回 #\{l"-  
try{ H*n-_{h"t  
if(bFirst) !)f\%lb  
{ zpn9,,~u  
nFileLength = getFileSize(); ^dWa;m]l  
if(nFileLength == -1) gjyYCjF  
{ kt#fMd$  
System.err.println("File Length is not known!"); K-)] 1BG  
} ),%%$G\  
else if(nFileLength == -2) tAd%#:K  
{ z_$%-6  
System.err.println("File is not access!"); ~7w"nIs<c  
} 8Al{+gx@?  
else Z?q]bSIT  
{ +HpA:]#Y  
for(int i=0;i<nStartPos.length;i++) Vr)S{k-Q  
{ 6Igz:eX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1ba~SHi  
} bSlF=jT[S  
for(int i=0;i<nEndPos.length-1;i++) /{J4:N'B>  
{ z|J_b"u4  
nEndPos = nStartPos[i+1]; yPBZc h%-  
} Tk[ $5u*,  
nEndPos[nEndPos.length-1] = nFileLength; oH?b}T=9jz  
} 9rX&uP)j^#  
} \.{$11P#  
x8B}ZIbT9  
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//启动子线程 xIW3={b3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; sE<V5`Z=  
for(int i=0;i<nStartPos.length;i++) %\#8{g  
{ ,8uqdk-D  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6Pnjmw.HV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2,oKVm+  
nStartPos,nEndPos,i); NiEUW.0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,-LwtePJ0  
fileSplitterFetch.start(); {z5--TogJ  
} r,3DTBe  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UhWNl]Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8'[7 )
I=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ZU4nc3__  
nEndPos = " + nFileLength); mDABH@R  
// fileSplitterFetch[nPos.length-1].start(); IPKbMlV#d  
XEp{VC@=  
lv<*7BCp  
//等待子线程结束 ek\ xx  
//int count = 0; u%KTNa0  
//是否结束while循环 ~H_/zK6e  
boolean breakWhile = false; 10~k2{Z  
_/$Bpr{R  
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while(!bStop) Lx1FpHo  
{ }OR@~V{Gj  
write_nPos(); t#})Awy^R  
Utility.sleep(500); iC32nY?  
breakWhile = true; wu!59pL  
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for(int i=0;i<nStartPos.length;i++) 85$m[+md  
{ [A~xy'T  
if(!fileSplitterFetch.bDownOver) K(rWNO  
{ WRbj01v  
breakWhile = false; !u[9a;Sa#  
break; %6,SKg p  
} Id'-&tYG  
} z&)A,ryW0  
if(breakWhile) z"L/G  
break; qPK*%Q<;  
m+R[#GE8#  
||= )d&  
//count++; K~{$oD7!  
//if(count>4) X6X $Pve  
// siteStop(); ,/%=sux  
} Su7?;Oh/yI  
bKY7/w<dP  
7M!I8C0!aO  
System.err.println("文件下载结束！");  .-c4wm}  
} u#$]?($}d  
catch(Exception e){e.printStackTrace ();} n8 i] z  
} ay ;S4c/_  
gMmaK0uhS  
/GN<\_o=q  
//获得文件长度 ,t?B+$E  
public long getFileSize() ,X-bJA@(  
{ h$>-.-  
int nFileLength = -1; zuad~%D<I  
try{ 6+|do+0Icg  
URL url = new URL(siteInfoBean.getSSiteURL());  :D6 ON"6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nu[ML  
httpConnection.setRequestProperty("User-Agent","NetFox"); R6Km\N  
Fn;SF4KOm  
gnOt+W8  
int responseCode=httpConnection.getResponseCode(); Nho>f  
if(responseCode>=400) ^R7lom.  
{ %KhI>O<  
processErrorCode(responseCode); 'Ym9;~(@R  
return -2; //-2 represent access is error x7&B$.>3  
} t7Iv?5]N  
!mJ"gg  
ZF9z~9  
String sHeader; Z, Yb&b  
rNWw?_H-H(  
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for(int i=1;;i++) ?}tFN_X"  
{ (ylTp]~mR-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @sW24J1q+  
//Utility.log(in.readLine()); @]%IK
(|  
sHeader=httpConnection.getHeaderFieldKey(i); !*dI|k  
if(sHeader!=null) Eex~xiiV  
{ nLZTK&7}  
if(sHeader.equals("Content-Length")) )Xz,j9GzJS  
{ eC
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ifMRryN4  
break; wo;~7K  
} 7Jyy z,!5  
} en4k/w_  
else a od-3"7[  
break; |}s*E_/[  
} b.Ju
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} VK\X&Y3l  
catch(IOException e){e.printStackTrace ();} jKAEm  
catch(Exception e){e.printStackTrace ();} DZ'P@f)]  
{0Yf]FQb-a  
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Utility.log(nFileLength); jjB~G^n  
m<
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return nFileLength; `!;_ho  
} gZ3u=uME  
Xv5wJlc!d  
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//保存下载信息（文件指针位置） r"
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private void write_nPos() ^B.5GK)!  
{ p?%y82E  
try{ c \J:![x  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Y1W1=Uc uk  
output.writeInt(nStartPos.length); K,;E5  
for(int i=0;i<nStartPos.length;i++) ~tS Z%q  
{ F4-$~v@  
// output.writeLong(nPos); TVtvuvQ2K  
output.writeLong(fileSplitterFetch.nStartPos); TTX5EDCrC  
output.writeLong(fileSplitterFetch.nEndPos); ok"
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} Y|F9}hj(  
output.close(); I#Y22&G1  
} E1aHKjLQ  
catch(IOException e){e.printStackTrace ();} O_muD\  
catch(Exception e){e.printStackTrace ();} a8e6H30Sm  
} T9E+\D  

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>-RQ]?^  
//读取保存的下载信息（文件指针位置） ~OYiq}g  
private void read_nPos() x*\Y)9Vgy  
{ }#RakV4  
try{ av8B-GQI*#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Hh3X
\  
int nCount = input.readInt(); iJI }TVep#  
nStartPos = new long[nCount]; I3{PZhU.  
nEndPos = new long[nCount]; CAig]=2'  
for(int i=0;i<nStartPos.length;i++) Wq D4YGN  
{ 2G& a{  
nStartPos = input.readLong(); 9rA0lqr]5  
nEndPos = input.readLong(); "+R+6<"  
} PfAgM1  
input.close(); 7FP*oN?  
} $D~0~gn~  
catch(IOException e){e.printStackTrace ();} jE.N ev/  
catch(Exception e){e.printStackTrace ();} Ws3)gvpPA  
} S:#lH?<_  
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)  
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private void processErrorCode(int nErrorCode) hlvK5Z  
{ &.)^ %Tp\z  
System.err.println("Error Code : " + nErrorCode); >;aWz%-  
} z3{G9Np  
n:I,PS0H<  
c)6m$5]  
//停止文件下载 fZGX}T<)p-  
public void siteStop() .ljnDL/  
{ pGP7nw_g  
bStop = true; jh?H.;**  
for(int i=0;i<nStartPos.length;i++) Y#ap*  
fileSplitterFetch.splitterStop(); :DK {Vg6  
8?B!2  


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} 0I-9nuw,^;  
} ('4_ xOb  
//负责部分文件的抓取 [NjXO`5#]  
**FileSplitterFetch.java k{R>  
*/ 60^`JVGWH  
package NetFox; p;`>e>$  
j1Y~_  
L Tm2G4+]  
import java.io.*; !,_u)4  
import java.net.*; hIYNhZv  
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public class FileSplitterFetch extends Thread { 5zK4Fraf  
K(e$esLs-  
1SQ3-WUs  
String sURL; //File URL Ljm[?*H#  
long nStartPos; //File Snippet Start Position D%[mWc@1I  
long nEndPos; //File Snippet End Position r(>@qGN  
int nThreadID; //Thread's ID k>Is:P  
boolean bDownOver = false; //Downing is over VD;01"#'  
boolean bStop = false; //Stop identical l5Uiw2  
FileAccessI fileAccessI = null; //File Access interface *nT<m\C6  
t
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException rK8lBy:<  
{ nmee 'oEw  
this.sURL = sURL; |"q5sym8Y_  
this.nStartPos = nStart; {LI=:xJJv  
this.nEndPos = nEnd; rm'SOJVA  
nThreadID = id; ]6k\)#%2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 f=+
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} JMCKcZ%N  
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public void run() ?.m bK  
{ >F|>c
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while(nStartPos < nEndPos && !bStop) 6
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{ M5LfRBO  
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try{  C#.->\  
URL url = new URL(sURL); O#4&8>;=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i'<[DjMDlm  
httpConnection.setRequestProperty("User-Agent","NetFox"); : g7@PJND  
String sProperty = "bytes="+nStartPos+"-"; F@D`N0Pte  
httpConnection.setRequestProperty("RANGE",sProperty); `{@8Vsmy:  
Utility.log(sProperty); ''cInTCr  
d"
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ql Ax  
InputStream input = httpConnection.getInputStream(); `GBW%X/  
//logResponseHead(httpConnection); \k7"=yx  
#"6Qj'/h  
tH@Erh|%  
byte[] b = new byte[1024]; ^cC,.Fdw  
int nRead; OU\~::  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) o+iiSTJEe  
{ 7DogM".}~Q  
nStartPos += fileAccessI.write(b,0,nRead); (Bb5?fw  
//if(nThreadID == 1) 5X:AbF  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6D;Sgc5"  
} G6Axs1a  
fivw~z|[@  
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Utility.log("Thread " + nThreadID + " is over!"); V;VHv=9`o  
bDownOver = true; -a}Dp~j  
//nPos = fileAccessI.write (b,0,nRead); 5+0gR &|j  
} Lz}OwKl  
catch(Exception e){e.printStackTrace ();} 0@0w+&*"@  
} dmtr*pM_  
} =osk+uzzG  
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H064BM  
//打印回应的头信息 /|m2WxK)  
public void logResponseHead(HttpURLConnection con) S&5&];Ag  
{ H\"sgoJ  
for(int i=1;;i++) Wx%H%FeK  
{ kOrZv,qFG[  
String header=con.getHeaderFieldKey(i); _#E0g'3  
if(header!=null) :wyno#8`-
 
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Vi
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Utility.log(header+" : "+con.getHeaderField(header)); "m$##X\  
else IZ-1c1   
break; J9nX"Sb  
} PCee<W_%YE  
} ' ,wFTV&  
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public void splitterStop() oAVnK[EMq`  
{ wc@X.Q[  
bStop = true; e`_LEv  
} ;W )Y OT  
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} 9Q^r O26+  
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)gUR@V>e2  
/* A1$T
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**FileAccess.java ] )\Pqn(  
*//文件访问(定位，写) \~mT] '5  
package NetFox; LKB$,pR~1l  
import java.io.*; Y=?3 js?O  
;u ({\K
 
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public class FileAccessI implements Serializable{ E?f-wQF  
l}|%5.5-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9wUkh}s  
RandomAccessFile oSavedFile; <?.&^|kS  
long nPos; rl;
~pO5R9  
yjX9oxhtL  
V#$RR!X'  
public FileAccessI() throws IOException A2Ed0|By  
{ ',@3>T**  
this("",0); `:K
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} M#6W(|V/  
7hcYD!DS  
<oV(7  
public FileAccessI(String sName,long nPos) throws IOException O"9\
5(
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{ oxA<VWUNT
 
oSavedFile = new RandomAccessFile(sName,"rw"); zT]8KA   
this.nPos = nPos; Af2( 5]  
oSavedFile.seek(nPos); RWZSQ~  
} ;7V%#-  
L|7R9+ZG  
]y'>=a|T  
public synchronized int write(byte[] b,int nStart,int nLen) ^A/k)x6  
{ g3/W=~r  
int n = -1; 9wwqcx)3(  
try{ ~rKrpb]ow  
oSavedFile.write(b,nStart,nLen); sY Q
k  
n = nLen; Qbn"=n2  
} $k%2J9O  
catch(IOException e) I"<\<^B<  
{ \V8PhO;j  
e.printStackTrace (); Qd$nH8EDY  
} zu{P#~21  
}q`S$P;  
"ne?P9'hF  
return n; %T%sGDCV  
} \&3+D8H>n  
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$ @`V  
} NP3
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6j]0R*B7`Q  
/* g7`LEF <A  
**SiteInfoBean.java K`zdc`/  
*/ Fj3a.'  
package NetFox; c9u`!'g`i  
'XjZ_ng  
agDM~=#F  
public class SiteInfoBean { @,7GaK\  
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?X<eV1a   
private String sSiteURL; //Site's URL E]n&=\  
private String sFilePath; //Saved File's Path D8?Vn"  
private String sFileName; //Saved File's Name ,m|h<faZL
 
private int nSplitter; //Count of Splited Downloading File h]}wp;Z  
{]@= ijjf  
0-Ku7<a  
public SiteInfoBean() >jLY"  
{//nSplitter的缺省值为5 ~4Fvy'  
//default value of nSplitter is 5 R.1.
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this("","","",5); 4p;`C  
} Js?]$V"  

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!F'YDjTot  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) By4<2u38u  
{ 2eY_%Y0  
sSiteURL= sURL; ;'@9[N9  
sFilePath = sPath;
m&,(Jla  
sFileName = sName; #h ]g?*}OJ  
this.nSplitter = nSpiltter; `dN@u@[\ks  
?NsW|w_  
d/kv|$XW  
} %l[( Iw  
+\ .Lp 5  
nmKp[-5  
public String getSSiteURL() GGs}i1m  
{ \Uq(Zga4)  
return sSiteURL; ?%[@Qb=2  
} `b7t4d*  
m&&m,6``P  
yN(%-u"  
public void setSSiteURL(String value) R-d:j^:f  
{ `+:`_4  
sSiteURL = value; ]Q)OL  
} je=a/Y=%U{  

1\2no{Vh  
j'"J%e]  
public String getSFilePath() $B5aje}i  
{ Pw"-S?`(  
return sFilePath; 9EibIOD^/  
} wjB:5~n50k  
cU!vsdR3  
=MDysb&:  
public void setSFilePath(String value) @<EO`L)Z  
{ ar+9\  
sFilePath = value; v;D~Pa  
} BuXqd[;K%  
mtcw#D  
mGg+.PFsM  
public String getSFileName() FP4P|kl/9'  
{ z[qDkL  
return sFileName; {8bSB.?R  
} U0P~  
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tJ$_lk ~6q  
public void setSFileName(String value) |[b{)s?x  
{ }a(dyr`S  
sFileName = value; z1X`o  
} gT6jYQ  
#5o(h+w)  
hf&9uHN%7m  
public int getNSplitter() JYHl,HH#z  
{ _L=h0H l  
return nSplitter; q9s=~d7  
} LyFN.2q
w  
' %o#q6O  
C,|,-CY  
public void setNSplitter(int nCount) 28d'7El$  
{ j*r{2f4Rt  
nSplitter = nCount; *VxgARIL  
} 3AN/ H  
} |Ds1  
^.QzQ1=D  
ge8ZsaiU  
/* Qh\60f>0  
**Utility.java V)N%WXG  
*/ Z4 =GMXj  
package NetFox; Z"fJ`--  
p H2Sbs:Tk  
9CD_os\h  
public class Utility { W
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ye5&)d"fa(  
</*6wpN  
public Utility() XU(eEnmom  
{ &0JI!bR(  
k~nBiV  
YT(AUS5n  
} `3&v6  
%n9aaoD  
//线程睡眠 XlR@pr6tw  
public static void sleep(int nSecond) l2Rb\4  
{ DN:EB@  
try{ 7hPY_W y  
Thread.sleep(nSecond); ?.BC#S)q1  
} @E|}Y  
catch(Exception e) oXF.1f/h  
{ vy
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e.printStackTrace (); }&D32\  
} U-M>=3|N  
} +52{-a,>  
0n{=%Q  
//日志 P/_['7  
public static void log(String sMsg) j&qub_j"xX  
{ }*]-jWt1J\  
System.err.println(sMsg); gRcQt:  
} g`QEu 5v  
[d]9Oa4  
TuaBm1S{f  
public static void log(int sMsg) h@ryy\9  
{ R4:b{)=O  
System.err.println(sMsg); f) L  
} )lDD\J7  
} IjnU?Bf  
d/~9&wLSb  
.%  
/* z~s PXGb  
**TestMethod.java 13x p_j  
*/ `VguQl_,gA  
package NetFox; b4N[)%@  
m ~$v;?i  
X!EP$!  
public class TestMethod { 8YSAf+{FtK  
:^h$AWR^f  
-zfR)(zG  
public TestMethod() LZxNAua  
{ ///xx/weblogic60b2_win.exe o?Oc7$+u  
try{ 7HYwLG:\~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); @f3E`8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %d9uTm;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >i?oC^QM  
fileFetch.start(); O?#7N[7  
} b@hqz!)l`  
catch(Exception e){e.printStackTrace ();} '!B&:X)  
J5,9_uo]  
c@L< Z`u  
} U|R_OLWAg  
S{T >}'y  
]3Sp W{=^(  
public static void main(String[] args) q'Pf]
  
{ )zDCu`  
new TestMethod(); &wDs6xq  
}  o-B$J?  
} X|]AT9W  
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