http断点续传简单实现（java)

/* Bc&Y[u-n  
**SiteFileFetch.java #l 7(WG  
*/ !A":L0[7n  
package NetFox; &Zy%Zz  
import java.io.*; rJtpTV@.  
import java.net.*; [SJ3FZ
<  
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public class SiteFileFetch extends Thread { pm` f?
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SiteInfoBean siteInfoBean = null; //文件信息Bean T]oVNy  
long[] nStartPos; //开始位置 zPm|
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long[] nEndPos; //结束位置 `]F}O \H  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6 H{G$[2  
long nFileLength; //文件长度 nOTe 3?i>  
boolean bFirst = true; //是否第一次取文件 f0M5^  
boolean bStop = false; //停止标志 f9$8$O  
File tmpFile; //文件下载的临时信息 o*_arzhA  
DataOutputStream output; //输出到文件的输出流 Be;l!]i  
<~z@GMQCf  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 40=*Ul U-  
public SiteFileFetch(SiteInfoBean bean) throws IOException *{x8@|K8  
{ tY@+d*u  
siteInfoBean = bean; =W[M=_0u  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); zoibinm}Eg  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); T0|hp7WM  
if(tmpFile.exists ()) kltorlH  
{ JO-FnoQK  
bFirst = false; @PzRHnT*  
read_nPos(); ,
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} F rd>+  
else <5O:jd  
{ P1_6:USBM  
nStartPos = new long[bean.getNSplitter()]; &[b(Lx|i  
nEndPos = new long[bean.getNSplitter()]; C[R|@9NI  
} *)bh6b=7  
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} >1BDt:G36  
bt=z6*C>A  
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public void run()  |\FJ  
{ \)M EM=U  
//获得文件长度 6DVHJ+WTV  
//分割文件 y?'Z'  
//实例FileSplitterFetch blx"WVqo  
//启动FileSplitterFetch线程 B,b^_4XX$  
//等待子线程返回 LkyT4HC8n  
try{ sW]>#e  
if(bFirst) X"!tx  
{ EG!Nsb^,  
nFileLength = getFileSize(); "M}3T?0 O  
if(nFileLength == -1) tS3!cO\  
{ w!r.MWE  
System.err.println("File Length is not known!"); !ZS5}/ZU  
} {VE1c'E"V?  
else if(nFileLength == -2) |-9##0H  
{ ST1;i5   
System.err.println("File is not access!"); `3^%ft~l  
} 3[UaK`/1C  
else 7*eIs2aY  
{ _ |G') 9  
for(int i=0;i<nStartPos.length;i++) oM!zeJNA  
{ Bo4iX,zu  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /u~L3Cp(  
} RDxvN:v  
for(int i=0;i<nEndPos.length-1;i++) ?$@E}t8g\  
{ D\Fu4Eg  
nEndPos = nStartPos[i+1]; t vp kc;  
} Dc9Fb^]QOG  
nEndPos[nEndPos.length-1] = nFileLength; W~& QcSWqD  
} [{PmU~RMYf  
} Iuve~ugO  
'tDV
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xzw2~(lo  
//启动子线程 ZMEYF!jN  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,8.zbr  
for(int i=0;i<nStartPos.length;i++) uCjbb  
{ Ssd7]G+n:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !DBaC%TGC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Wb#ON|.2  
nStartPos,nEndPos,i); Yb348kRF  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /Py`a1  
fileSplitterFetch.start(); ]]hsLOM]  
} EouI S2e;a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X\|h:ce  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .-:@+=(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _#yd0E  
nEndPos = " + nFileLength); Of;$ VK'  
// fileSplitterFetch[nPos.length-1].start(); 6$G@>QCBS  
Z8:'_#^@a[  
F\%PB p  
//等待子线程结束 u>.>hQ  
//int count = 0; ^.~ F_  
//是否结束while循环 ,-V7~gM%}  
boolean breakWhile = false; B/K
{sI  
@<$_X1)s  
;HmQRiCg  
while(!bStop) ^.>XDUO F  
{ MC_i"P6a  
write_nPos(); eY\!}) 5  
Utility.sleep(500); OSkBBo]~z  
breakWhile = true; gmCB4MO  
V4. }wz_Y  
'ALe>\WO  
for(int i=0;i<nStartPos.length;i++) r5Xi2!  
{ 4Y{&y6  
if(!fileSplitterFetch.bDownOver) ^}4ysw  
{ {^@qfkZ
z^  
breakWhile = false; G3D!ifho.#  
break; jN%+)Kj0C)  
} L[Y|K%
;~  
} kOV6O?h  
if(breakWhile) }4_c~)9Q  
break; 7jPn6uz>w  
y*j8OA.S  
78O5$?b;#  
//count++; ;f[@zo><r  
//if(count>4) H8$";T(I  
// siteStop(); (h27SLYm  
} r'J3\7N!u  
rm!.J0 X  
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System.err.println("文件下载结束！"); ~c'R7E&Bfa  
} m@y_Wt  
catch(Exception e){e.printStackTrace ();} 4(p,@e
31  
} :s
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% ^&D,  
*Vp$#Rb  
//获得文件长度 P"k,[ZQ  
public long getFileSize() 1#jvr_ ga  
{ Ts3(,
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int nFileLength = -1; qR8 BS4q_p  
try{ 33w(Pw  
URL url = new URL(siteInfoBean.getSSiteURL()); eo'C)j# U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b*o,re)Dj  
httpConnection.setRequestProperty("User-Agent","NetFox"); !Nno@SP@  
hP=z<&zb/  
]]_H|tO  
int responseCode=httpConnection.getResponseCode(); {-,^3PI\  
if(responseCode>=400) @-BgPDi.Z  
{ f2FGod<CzN  
processErrorCode(responseCode); ,E8~^\HV  
return -2; //-2 represent access is error BXX1G  
} Wg5i#6y8w  
E3E$_<^  
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String sHeader; dWhF[q"  
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*,p
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for(int i=1;;i++) Vr<ypyC  
{ }{@RO./)[  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); O:(%m  
//Utility.log(in.readLine()); ?mW;%d~]  
sHeader=httpConnection.getHeaderFieldKey(i); -cnlj  
if(sHeader!=null) RYKV?f#[H  
{ eO
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if(sHeader.equals("Content-Length")) k<\]={|=  
{ 7x:j4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Y$6W~j  
break; O7\)C]A  
} von~-51;  
} ~*uxKEH  
else LdYaJh~h  
break; |h65[9DMP  
}
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} ^Sz?c_<2
P  
catch(IOException e){e.printStackTrace ();} M)!:o/!cS  
catch(Exception e){e.printStackTrace ();} s\i.pd:Q  
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QTjOLK$e$  
Utility.log(nFileLength); DwC8?s*2H  
Eb=;D1)y]  
/WIHG0D  
return nFileLength; -Fs^^={Q  
}  LYX\#  
5s2334G  
7&9'
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//保存下载信息（文件指针位置） wq"AWyu  
private void write_nPos() D^H<)5d9  
{ 1MzOHE
 
try{ me`(J y<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); G0eJ<*|_ 3  
output.writeInt(nStartPos.length); Ig6>+Mw  
for(int i=0;i<nStartPos.length;i++) mLn =SU{#  
{ MF^I] 7_  
// output.writeLong(nPos); P=9Zm  
output.writeLong(fileSplitterFetch.nStartPos); ^NTOZ0x~#
 
output.writeLong(fileSplitterFetch.nEndPos); B.J4
}Ua  
} >}ozEX6c2  
output.close(); :}18G}B  
} GQ
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catch(IOException e){e.printStackTrace ();} [{B1~D-  
catch(Exception e){e.printStackTrace ();} q3E_.{t  
} kVZ5>D$  
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//读取保存的下载信息（文件指针位置） P'6(HT>F?  
private void read_nPos() !S',V&Yb  
{ 'E,Bl]8C5  
try{ kM\O2ay  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >AW=N  
int nCount = input.readInt(); '2%/h4jY  
nStartPos = new long[nCount]; V F'! OPN  
nEndPos = new long[nCount]; hOx">yki  
for(int i=0;i<nStartPos.length;i++) 3f:I<S7  
{ B1A5b=6G<  
nStartPos = input.readLong(); 2JYt.HN  
nEndPos = input.readLong(); R`:NUGR  
} ^50/.Z>  
input.close(); ;pNHT*>u,  
} <`q|6XWL  
catch(IOException e){e.printStackTrace ();} _k@{> ?(a  
catch(Exception e){e.printStackTrace ();} 
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} Wwf#PcC]  
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private void processErrorCode(int nErrorCode) 9c=_p'G3Fw  
{ -$4%@Z  
System.err.println("Error Code : " + nErrorCode); WLWE%bDP  
} ?WX&,ew~  
Cs %-f"  
BKm$H!u  
//停止文件下载 EhybaRy;C  
public void siteStop() ?fEX&t,'  
{ hqY9\,.C  
bStop = true; $
{ ~UA6  
for(int i=0;i<nStartPos.length;i++) MNiu5-g5  
fileSplitterFetch.splitterStop(); p\8
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} >M^ 1m(  
} [lA[wCw  
//负责部分文件的抓取 8P!dk5,,O  
**FileSplitterFetch.java ys;e2xekg  
*/ @"HR"@pX  
package NetFox; ?Y'S /  
u hP0Zwn  
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import java.io.*; :u{0M&  
import java.net.*; dTaR8i  
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h& (@gU`A  
public class FileSplitterFetch extends Thread { 2`vCQV  
rA9x T`  
C<fNIc~.  
String sURL; //File URL *ftJ(  
long nStartPos; //File Snippet Start Position fT8Id\6js  
long nEndPos; //File Snippet End Position EBM\p+x&  
int nThreadID; //Thread's ID 64\ZOG\,  
boolean bDownOver = false; //Downing is over c`X'Q)c&K  
boolean bStop = false; //Stop identical $YSD%/c  
FileAccessI fileAccessI = null; //File Access interface x[}e1sXXs  
C)z[Blt  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException A0rdQmrOL  
{ Ytx+7OLe  
this.sURL = sURL; o
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this.nStartPos = nStart; BPrA*u}T  
this.nEndPos = nEnd; 4_N)1u !  
nThreadID = id; ja7Zv[  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 gH\r# wy|  
} 0 \LkJ*i  
dtM
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#G.3a]p}"  
public void run() 2a=WT`xf?  
{ %T6#c7U_  
while(nStartPos < nEndPos && !bStop) ''BP4=r5n  
{ !Y]}&
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try{ @?Y^=0  
URL url = new URL(sURL); OV8b~k4=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R/^JyL  
httpConnection.setRequestProperty("User-Agent","NetFox"); cT0utR
&  
String sProperty = "bytes="+nStartPos+"-"; 0uU%jN$  
httpConnection.setRequestProperty("RANGE",sProperty); 4&ea*w  
Utility.log(sProperty); MmWJYF=  
&OhKx  
SC2C%.%l`  
InputStream input = httpConnection.getInputStream(); qqzQKN  
//logResponseHead(httpConnection); t48(GKF  
{C]M]b*F6(  
4rM77Uw>  
byte[] b = new byte[1024]; 1wc -v@E  
int nRead; -'PpY302  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6eDIS|/  
{ GYO\l.%V5y  
nStartPos += fileAccessI.write(b,0,nRead); 7Xad2wXn  
//if(nThreadID == 1) iY|YEi8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qfSo
F|  
} fSqbGoIQ  
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Utility.log("Thread " + nThreadID + " is over!"); 50DPzn  
bDownOver = true; NNl/'ge<\  
//nPos = fileAccessI.write (b,0,nRead); M@'V4oUz  
} (C-z8R Z6  
catch(Exception e){e.printStackTrace ();} WQ5sC[&   
} &YT7>z,  
} Bd NuhV`0  
i9!Urq-  
=|U2 }U;  
//打印回应的头信息 4G>|It  
public void logResponseHead(HttpURLConnection con) =(n'#mV  
{ 3K?0PRg  
for(int i=1;;i++) 3yKI2en"  
{ AVyZ#`,  
String header=con.getHeaderFieldKey(i); MW`a>'0t?  
if(header!=null) /a$+EQ$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D`t
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Utility.log(header+" : "+con.getHeaderField(header)); rmMO-!s  
else Yip9K[  
break; >|Jw,,uf  
} jujx3rnK?  
} D} .t  
3-mw-;.  
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public void splitterStop() `C*!de]Y%  
{ f<w*l<@  
bStop = true; VNYLps@4H  
} <Y#R]gf1  
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4o*V12_r'4  
} pK8nzGQl7  
__ mtZ{  
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/* 9#iDrZW  
**FileAccess.java 5dgBSL$A}]  
*//文件访问(定位，写) JA{YdB;il  
package NetFox; ^mum5j
 
import java.io.*; ]Qu12Wg}P  
tl)}Be+Dt;  
.d"+M{I  
public class FileAccessI implements Serializable{ oX}n"5o:  
R{
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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 "T&uS1+=c  
RandomAccessFile oSavedFile; uWWv`bI>x  
long nPos; NdNfai  
%7d"()L  
n21$57`4  
public FileAccessI() throws IOException c}QJ-I  
{ wi9|  
this("",0); Q jBCkx]g  
} Yjl0Pz.q  
}-L@AC/\#  
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public FileAccessI(String sName,long nPos) throws IOException d_,tXV"z&  
{ m@,>d_|-K-  
oSavedFile = new RandomAccessFile(sName,"rw"); yQA[X}  
this.nPos = nPos; epbp9[`  
oSavedFile.seek(nPos); =a!6EkX *  
} pMquu&Td  
V1:3  
]T51;j'48  
public synchronized int write(byte[] b,int nStart,int nLen) |f:d72{Qr  
{ q8h{-^"  
int n = -1; Qwa"AY5pW  
try{ gr?pvf!I  
oSavedFile.write(b,nStart,nLen); @ RI^wZ-;  
n = nLen; 'sF563kE  
} d>`(.qvxR  
catch(IOException e) K%}I}8M  
{ Q#Y3%WF  
e.printStackTrace (); H n!vTB  
} h(8;7}K  
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c
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return n; +lT]s#Fif  
} wY.g-3  
]= NYvv>H  
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} +zdkdS,2<  
+r$.v|6  
/ 3k\kkv!  
/* 0tqR wKL  
**SiteInfoBean.java ee_\_"  
*/ Tqa4~|6  
package NetFox; 9AYe,R  
%~5Q^3$O  
L%d?eHF  
public class SiteInfoBean { 12PE{Mut  
lDU:EJ&DHE  
h<K;VpL6  
private String sSiteURL; //Site's URL N ]7a=  
private String sFilePath; //Saved File's Path zsXH{atY  
private String sFileName; //Saved File's Name t4k'9Y:\Q  
private int nSplitter; //Count of Splited Downloading File 'q'Y:A?,  
8~)[d!'  
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public SiteInfoBean() ++!E9GU{  
{//nSplitter的缺省值为5 'TrrOq4  
//default value of nSplitter is 5 G r|@CZq  
this("","","",5); j$|C/E5?  
} r65
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3Gl]g/  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) C55n  
{ Kg`x9._2  
sSiteURL= sURL; 7=.VqC^  
sFilePath = sPath; Z{ Zox[/  
sFileName = sName; G^ZkY  
this.nSplitter = nSpiltter; &8AS=v  
un^IQMIh  
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} fJw=7t-t  
56Y5kxmi  
:J`!'{r  
public String getSSiteURL() C)
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{ i>Bi&azx  
return sSiteURL; 6&QTVdK'O  
} 7 3z Y^x  
9H}iX0O  
A4Q)YY9~  
public void setSSiteURL(String value) 6+;2B<II  
{ iB3+KR  
sSiteURL = value; f5b`gvCY,#  
} pd>a6 lI`  
~R@m!'Ik  
:/[YY?pg-  
public String getSFilePath() : |*,Lwvd  
{ sHTePEJ_h  
return sFilePath; w52HN;Jm  
} y]YS2^  
}Q=se[((  
Zc3:9  
public void setSFilePath(String value) 5652'p  
{ Z^`=!n-V  
sFilePath = value; g} ~<!VpX  
} 3:8nwt  
lcT+$4zk.  
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public String getSFileName() ]<;i}n| <  
{ WUWb5xA  
return sFileName; Rf(x^J{  
} ]AC!R{H  
u1|P'>;lF  
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public void setSFileName(String value) A[ECa{v  
{ 2V2x,!  
sFileName = value; UE,~_hp  
} ~R?dD
L  
9Oo*8wvGG  
;Jbc'V'fm  
public int getNSplitter() k *;{n8o?)  
{ Sp~Gv>uMK  
return nSplitter; FX|lhwmc(  
} KpbZnW}g  
FSwgPIO>  
h>^jq{yu  
public void setNSplitter(int nCount) 
: 9?Cm`  
{ ,Z*3,/a  
nSplitter = nCount; K?Xo3W%K  
} 1[/$ZYk:  
} d[RWkk5  
n|mJE,N  
>H1|c%w  
/* .f !]@"\  
**Utility.java 7z&adkG:  
*/ 'q};L6  
package NetFox; >uchF8)e|  
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;[OJ-|Q  
public class Utility { @maZlw1q  
itC *Z6^  
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public Utility() vBnKu  
{ $XQ;~i   
q:-]d0B+  
lq\'  
} F'UguC">  
Dmm r]~  
//线程睡眠 fs3-rXoB  
public static void sleep(int nSecond) CVGOX z  
{ ]EVe@  
try{ o3i,B),K  
Thread.sleep(nSecond); Xc9p;B>^Ts  
} <(bCz>o|  
catch(Exception e) N+C)/EN$  
{ \o62OfF!  
e.printStackTrace (); FU(}=5n  
} zhA',p@K?_  
} ^iV`g?z  
.e FOfV)  
//日志 l)i&ATvCE  
public static void log(String sMsg) Q/3tg  
{ ph8Jn
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System.err.println(sMsg); |>IUtUg\  
} 0?6If+AC  
:?$Sb8OuIL  
){:q;E]^fB  
public static void log(int sMsg) 47C(\\
 
{ 0V>ESyae5  
System.err.println(sMsg); X@bn??  
} QWzOp\+  
} r(,= uLc  
4Wi8$  
DYT@BiW{  
/* M}=s3[d(,  
**TestMethod.java #7-kL7 MK]  
*/ \8>  
package NetFox; 0\EpH[m}-  
k%Ma4_Z  
wuBlFUSg  
public class TestMethod { z<yNG/M1>U  
e>?_)B4  
7
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public TestMethod() ^)9MzD^_nV  
{ ///xx/weblogic60b2_win.exe xs2,t*  
try{ *l>[`U+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ;T5,T   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6Q
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SiteFileFetch fileFetch = new SiteFileFetch(bean); wO2V%v^bp  
fileFetch.start(); ,c,Xd  
} RV0>-@/x  
catch(Exception e){e.printStackTrace ();} z)58\rtz  
H-/; l54E  
.g/ARwM}  
} []A"]p  
]k::J>84  
?AeHVQ :C  
public static void main(String[] args) z`emKFbv  
{ >%uAQiU  
new TestMethod(); :rz9M@7  
} 3~[`[4n^  
} p@?7^nIR*u  
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