http断点续传简单实现（java)

/* -<5H8P-  
**SiteFileFetch.java B 3eNvUFZg  
*/ L_AQS9a^D  
package NetFox; y|%lw%cSe  
import java.io.*; 5dLb`Gf  
import java.net.*; Lw{'mtm  
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public class SiteFileFetch extends Thread { {"^#CSi  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 7=4V1FS6i  
long[] nStartPos; //开始位置 ld'Aaxl&  
long[] nEndPos; //结束位置 c6HH%|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;7yt,b5&C  
long nFileLength; //文件长度 B=2f-o  
boolean bFirst = true; //是否第一次取文件 +
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boolean bStop = false; //停止标志 Y.o-e)zX  
File tmpFile; //文件下载的临时信息 ptpu u=3"  
DataOutputStream output; //输出到文件的输出流 }x
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uX,ln(9I*H  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） _lG\_6oJ,  
public SiteFileFetch(SiteInfoBean bean) throws IOException NZ~"2~Hh  
{ #]Q.B\\  
siteInfoBean = bean; v&u8K
s  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =A^V
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0Yc
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if(tmpFile.exists ()) 6H!"oC&  
{ ]m
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bFirst = false;  TGozoPV  
read_nPos(); @RS|}M^4  
} CA ,0Fe3  
else $g)X,iQu  
{ qgsKbsl  
nStartPos = new long[bean.getNSplitter()]; 4N{^niq7  
nEndPos = new long[bean.getNSplitter()]; Z+x`q#ZQr  
} .Ue1}'v*,  
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} 8Vqh1<
 
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public void run() XDq*nA8#5B  
{ l050n9#9p  
//获得文件长度 $Z^HI  
//分割文件 *.Ceb
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//实例FileSplitterFetch T>s3s5Y  
//启动FileSplitterFetch线程 JIU=^6^2'  
//等待子线程返回 c*x5t"{  
try{ )~[hf,R5S  
if(bFirst) (SYSw%
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{ <f`G@  
nFileLength = getFileSize(); -AxO1 qO  
if(nFileLength == -1) ~m.@{Do0p  
{ <lwkjt=RV  
System.err.println("File Length is not known!"); E14Dq#L  
} ~uz4  
else if(nFileLength == -2) 2:l8RH!Y  
{ RgT|^|ZA  
System.err.println("File is not access!"); )]5}d$83  
} [D%5Fh\0  
else uVw|fT  
{ -?68%[4lm_  
for(int i=0;i<nStartPos.length;i++) o@KK/f  
{ QGQ>shIeZ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |Ptv)D  
} [.NG~ cpb  
for(int i=0;i<nEndPos.length-1;i++) [Dq!t1  
{ Qtpw0t"  
nEndPos = nStartPos[i+1]; DZ Q=Sinry  
} myeez+@ m  
nEndPos[nEndPos.length-1] = nFileLength; Th)Z?\8zk  
} 7B,axkr  
} &udlt//^%  
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aM|^t:  
//启动子线程 \P|PAU@,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G\1\L*+0  
for(int i=0;i<nStartPos.length;i++) B#K{Y$!v  
{ u:f.g?!`"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7U\GX  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "?UBW5nM#  
nStartPos,nEndPos,i); &z(E-w/S  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L^0s  
fileSplitterFetch.start(); [~<X|_LG  
} U6@Hgi>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B#T4m]E/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9I;d>%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]hL`HP  
nEndPos = " + nFileLength); t$lO~~atr  
// fileSplitterFetch[nPos.length-1].start(); e$3{URg  
]e+88eQ  
C.[abpc  
//等待子线程结束 @Js^=G2  
//int count = 0; af<R.  
//是否结束while循环 (/r l\I  
boolean breakWhile = false; lU[" ZFP  
O+^l>+ZGj?  
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while(!bStop) RHc-kggk!  
{ +(-L  
write_nPos(); ZCAdCKX|  
Utility.sleep(500); d/O~"d  
breakWhile = true; YxUC.2V|7$  
(93+b%^[  
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for(int i=0;i<nStartPos.length;i++) OIMsxXF\J  
{ 1]i{b/ 4  
if(!fileSplitterFetch.bDownOver) O:Ixy?b;Z  
{ n
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breakWhile = false; `"/s,"c:D  
break; *+ql{\am4N  
}
#Jo#[-r  
} uoM;p'  
if(breakWhile) ;ctJ9"_g
 
break; 1webk;IM  
ST#MCh-00  
+ S^OzCGk  
//count++; 0 xUw}T6  
//if(count>4) O#g'4 S  
// siteStop(); ebSG|F  
}  TM1isZ  
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System.err.println("文件下载结束！"); 1'[RrJ$Q  
} vjc
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catch(Exception e){e.printStackTrace ();} bV5
{  
} Cz%tk}2  
I0 78[3b  
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//获得文件长度 GxL;@%B  
public long getFileSize() R;wq
 
{ *oC],4y~D  
int nFileLength = -1; jo8hVWJ7V*  
try{ 'Olp2g8=  
URL url = new URL(siteInfoBean.getSSiteURL()); xpWx6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); X2? ^t]-N  
httpConnection.setRequestProperty("User-Agent","NetFox"); ZH:-.2*cj  
5,I|beM  
[\ M$a|K  
int responseCode=httpConnection.getResponseCode(); $?.0>0,<  
if(responseCode>=400) yM*-em  
{ @%7IZg;P6  
processErrorCode(responseCode); H
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return -2; //-2 represent access is error ?*36&Iq}  
} ^u?#fLr  
[]'gIF  
8!~8:?6n  
String sHeader; 4&}V
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for(int i=1;;i++) ''{REFjK7  
{ vr,8i7*0  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [z2XK4\e1T  
//Utility.log(in.readLine()); Xu4C*]A>  
sHeader=httpConnection.getHeaderFieldKey(i); g>m)|o'  
if(sHeader!=null) B}PT-S1l  
{ "$-
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if(sHeader.equals("Content-Length")) wxa?.  
{ u3"0K['3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?s=O6D&   
break; 0Jz5i4B  
} *Kpk1  
} 7,MDFO{
n  
else [g bYIwL.  
break; w1a
ev  
} F;4*,Ap  
} 6zo'w Wc3  
catch(IOException e){e.printStackTrace ();} ,g.*Mx`-
 
catch(Exception e){e.printStackTrace ();} 'pCZx9*c  
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Utility.log(nFileLength); {XHAQ9'  
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return nFileLength; UlG8c~p  
} =cwQG&as  
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aC\O'KcH  
//保存下载信息（文件指针位置） y /$Q5P+o  
private void write_nPos() y&ZyThqg  
{ B3+9G,or  
try{ [y(DtOR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q]JWWKt6rV  
output.writeInt(nStartPos.length); aG"j9A~ &  
for(int i=0;i<nStartPos.length;i++) z%)~s/2Rs  
{ 1JRM@!x  
// output.writeLong(nPos); 1V\tKDM  
output.writeLong(fileSplitterFetch.nStartPos); )\S3Q  
output.writeLong(fileSplitterFetch.nEndPos); o!]muO*Rm  
} Jy#c
6
 
output.close(); dRdI('  
} bW]7$?acv  
catch(IOException e){e.printStackTrace ();} ?QDHEC62  
catch(Exception e){e.printStackTrace ();} y*F !k{P  
} wbIgZ]o!/;  
N('=qp9  
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//读取保存的下载信息（文件指针位置） <r9L-4  
private void read_nPos() '|I8byiK  
{ xRX2u_f$<  
try{ %^bHQB%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); FAkrM?0/  
int nCount = input.readInt(); /C[Q?  
nStartPos = new long[nCount]; q,i&%  
nEndPos = new long[nCount]; *^ZJ&.  
for(int i=0;i<nStartPos.length;i++) J!{t/_aw  
{ eD|p1+76  
nStartPos = input.readLong(); f`$F^=  
nEndPos = input.readLong(); M_I.Y1|  
} Q9yIQ{>H[  
input.close(); ^n|yfvR  
} 3X;k c>  
catch(IOException e){e.printStackTrace ();} w#XD4kwQG  
catch(Exception e){e.printStackTrace ();} "{;E+-/ aL  
} wtl3Ex,DO  
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private void processErrorCode(int nErrorCode) 8l1s]Kqr  
{ uPT2ga]  
System.err.println("Error Code : " + nErrorCode); :*=fGwIWS  
} t3qPocYQ  
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lZ'WFFWLE  
//停止文件下载 OH\(;RN*  
public void siteStop() DruiiA  
{ 0P5s'2w  
bStop = true;  )>=!</@  
for(int i=0;i<nStartPos.length;i++) 4'+g/i1S F  
fileSplitterFetch.splitterStop(); u?-|sv*  
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} O .ESI  
} %eE0a4^".  
//负责部分文件的抓取 Sl;[9l2  
**FileSplitterFetch.java 2 rFjYx8D!  
*/ dwpE(G y6c  
package NetFox; RoFOjCc>D.  
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import java.io.*; `<Q[$z  
import java.net.*; kl~)<,/@  
y}F;~H~P  
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public class FileSplitterFetch extends Thread { ;!+-fn4C  
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String sURL; //File URL j|KjQ'9  
long nStartPos; //File Snippet Start Position 03/mB2|TF(  
long nEndPos; //File Snippet End Position Ud_7>P$a  
int nThreadID; //Thread's ID /h7u
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boolean bDownOver = false; //Downing is over [;Y,nSw  
boolean bStop = false; //Stop identical kSpy-bVn  
FileAccessI fileAccessI = null; //File Access interface h6Q~Di  
AI^!?nJ%'  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 'ti~TG  
{ 7BS5Eq B=  
this.sURL = sURL; ]#\De73K  
this.nStartPos = nStart; '5m4kDs  
this.nEndPos = nEnd; *mJ\Tzc)  
nThreadID = id; #z1/VZ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 5SMV3~*P  
} YNB7`:  
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public void run() l$&dTI<#  
{ 3#0y.. F  
while(nStartPos < nEndPos && !bStop) UQg_y3 #V  
{ *Fg)`M3g  
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try{ 
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URL url = new URL(sURL); 
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p9E/#U8A_  
httpConnection.setRequestProperty("User-Agent","NetFox"); wVq9t|V  
String sProperty = "bytes="+nStartPos+"-"; 8:;]tt  
httpConnection.setRequestProperty("RANGE",sProperty); ;nx.:f  
Utility.log(sProperty); i-}Tt<^  
TILH[r&Jg  
I 6'!b/  
InputStream input = httpConnection.getInputStream(); p/qu4[Mm  
//logResponseHead(httpConnection); P6I<M}p  
(!PsK:wc  
S"t\LB*'Ls  
byte[] b = new byte[1024]; ~dC.,"  
int nRead; iR!]&Oh  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) c{IL"B6>  
{ zm{`+boH<  
nStartPos += fileAccessI.write(b,0,nRead); %>y`VN D  
//if(nThreadID == 1) ' <?=!&\D  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #N$\d4q9  
} i-ww@XOQ  
(HXKa][T  
gZ|!'  
Utility.log("Thread " + nThreadID + " is over!"); UcKVLzKs  
bDownOver = true; MH|F<$42  
//nPos = fileAccessI.write (b,0,nRead); ifNyVEHy  
} gBO,  
catch(Exception e){e.printStackTrace ();} ckb(+*+l  
} !9{hbmF#  
} ~Zn|(  
AmZW=n2^  
{;|pcx\L6~  
//打印回应的头信息 ULhXyItL  
public void logResponseHead(HttpURLConnection con) BIS.,  
{ Fi'ZId  
for(int i=1;;i++) ilXKJJda  
{ D~bx'Wr+  
String header=con.getHeaderFieldKey(i); ,c-*/{3  
if(header!=null) psse^rFg  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); J(K/z,4h  
Utility.log(header+" : "+con.getHeaderField(header)); \*&?o51!e  
else /1p5KVTKv  
break; 6<9}>Wkf  
} <5"&]! .  
} ^We}i  

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{P,hH~!  
public void splitterStop() PhPe7^  
{ cs7^#/3<  
bStop = true; 2$MoKOx8$  
} bIlNA)g  
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B9Mp3[  
} Y<jX[ET!  
=''WA:,=h  
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/* A|4om=MO  
**FileAccess.java 3AglvGK7{  
*//文件访问(定位，写) a~J!G
:(  
package NetFox; 5}Id[%.x  
import java.io.*; 8#HnV%|N  
jo0XF]  
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public class FileAccessI implements Serializable{ f_$hK9I  
x[$KZGK+GL  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 a6gPJF[Jo  
RandomAccessFile oSavedFile; m+(g.mvK>  
long nPos; vQp'bRR  
_!VtM#G[  
~-[!>1!%  
public FileAccessI() throws IOException 5Po:$(  
{ +$#<gp"  
this("",0); pKpB  
} "O-X*>?f  
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public FileAccessI(String sName,long nPos) throws IOException xMNQT.A  
{ O9zMD8  
oSavedFile = new RandomAccessFile(sName,"rw"); Dn@ZS_f  
this.nPos = nPos; !H@HgJ -  
oSavedFile.seek(nPos); rM^2yr7H  
} 9-V'U\}L  
/t`,7y3T  
+ue1+#  
public synchronized int write(byte[] b,int nStart,int nLen) ',xUU{5?  
{ .>#O'Z&q9  
int n = -1; gOe!GnO  
try{ 4`)r1D!U  
oSavedFile.write(b,nStart,nLen); c-5AI{%bl6  
n = nLen; \b%c_e  
} FNuE-_  
catch(IOException e) y2#"\5dC  
{ 0;@>jo6,!  
e.printStackTrace (); d/jP2uuA  
} (_!I2"Q*  
vb?.`B_>&  
9od*N$  
return n; c_S~{a44Ud  
} #;~HoOK*#  
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} @8>bp#x/1  
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/* akNqSZwj  
**SiteInfoBean.java r180vbN$  
*/ hSw=Oq82  
package NetFox; Ha|}Oj  
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public class SiteInfoBean { qPD(D{,f$  
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private String sSiteURL; //Site's URL A.("jb@I  
private String sFilePath; //Saved File's Path ,b&hLht  
private String sFileName; //Saved File's Name .#bf9JOE  
private int nSplitter; //Count of Splited Downloading File HV)aVkr/&  
=f y|Dm74  
yc~<h/}#  
public SiteInfoBean() [|1I.AZ{  
{//nSplitter的缺省值为5 aQ$sn<-l  
//default value of nSplitter is 5 &.?E[db"h  
this("","","",5); {pH#zs4Y  
} |u?VlRt  
_"B.V(  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) zsQ|LwQ  
{ K$Vu[!l`  
sSiteURL= sURL; 2[Lv_<i|  
sFilePath = sPath; -$
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sFileName = sName; 7`;f<QNo  
this.nSplitter = nSpiltter; iLZY6?_^  
Ms,MXJtH  
?R#$ c]  
} nOL.%  
r9&m^,U  
yD7}  
public String getSSiteURL() kMurNA=  
{ Uzzm2OS`  
return sSiteURL; s$>n U  
} <^Vj1
s  
:=;{w~D  
}R#W<4:  
public void setSSiteURL(String value) Ve|:k5z  
{ f0sGE5  
sSiteURL = value; "E\mj'k  
} .gDq+~r8O  
\H:T)EV
y  
C
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public String getSFilePath() rX?ZUw?u&  
{ 9/{zS3h3  
return sFilePath; 8!Wh`n<  
} ').)0;  
Rv9jLH  
9D1WUUa  
public void setSFilePath(String value) 30uPDDvar  
{  #O}}pF  
sFilePath = value; ;\2Z?Kq  
} 4\&Y;upy+  
F!EiF&[\J  
hA5')te<  
public String getSFileName() A\Ib  
{ H,L{N'[Xph  
return sFileName; \(P?=] -  
} E|f[#+:+  
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8^ f:-5  
public void setSFileName(String value) {:uv}4Z  
{ BNNM$.ZIQ  
sFileName = value; rnj$u-8  
} j0mN4Ny  
i)|jLrW~e  
R*D<M3  
public int getNSplitter() }l7+W4~  
{ rl%,9JD!  
return nSplitter; &R<aRE:+R  
} @!f4>iUy  
NgGMsE\C}  
q%dG>!  
public void setNSplitter(int nCount)  < v]  
{ p 4>ThpX  
nSplitter = nCount; 70c]|5  
} lJu^Bcrv  
} {s0%XG1$  
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UrvUt$WO  
/* dz9U.:C  
**Utility.java Z{0BH{23  
*/ f+ceL'
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package NetFox; mg'q-G`\<  
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public class Utility { jn V=giBu  
w7U]-MW6A*  
b/z-W`gw  
public Utility() ja_8n["z  
{ ]WDmx$"&e  
^b+>r  
RtMI[  
} v<!S_7h  
S"Cz. bv  
//线程睡眠 {g%N(2  
public static void sleep(int nSecond) BUBx}dbCM  
{ eTS}-  
try{ JkAM:,^(  
Thread.sleep(nSecond); 13!@LbC  
} }~I!'J#)  
catch(Exception e) yQ[;y~W  
{ I$xZV?d.  
e.printStackTrace (); /IUu-/ D  
} :jl*Y-mM  
} C:J;'[,S  
fkzSX8a9}  
//日志 2H|:/y  
public static void log(String sMsg) /e'3\,2_  
{ LW]fme<V?  
System.err.println(sMsg); =*,SD
 
} y d97ys  
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dM-cQo:  
public static void log(int sMsg) 1(?4*v@B  
{ .zO2g8(VR  
System.err.println(sMsg); c1'@_Is  
} X,|8Wpi=  
} FXof9fa_B  

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|RiJ>/MK\  
/* !2L
X+*;  
**TestMethod.java K&|h%4O  
*/ RehmVkT  
package NetFox; ^Pn|Q'{/p  
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dE7x SI  
public class TestMethod { IK2da@V  
2a$.S" ?  
g<:Lcg"u  
public TestMethod() JY0aE  
{ ///xx/weblogic60b2_win.exe >H;i#!9,  
try{
FQ<-Wc  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +94)BxrY  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &bsq;)wzs  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +lym8n~-O  
fileFetch.start(); +vh|m5"7I7  
} XNYA\%:5S  
catch(Exception e){e.printStackTrace ();} ;>J!$B?,  
.Mq#88o.*  
&K9;GZS?  
} 4mX(.6  
_gT65G~z  
'$tCA
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public static void main(String[] args) jdxHWkQ  
{ TrjyU  
new TestMethod(); Lzh8-d=HQ  
} xE1?)  
} <>] DcA  
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