http断点续传简单实现（java)

/* ihBlP\C  
**SiteFileFetch.java ir-srVoXy  
*/ EyA}  
package NetFox; ie{9zO<d  
import java.io.*; kUUey
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import java.net.*; v4=9T<[  
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public class SiteFileFetch extends Thread { x6\EU=
,  
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SiteInfoBean siteInfoBean = null; //文件信息Bean *=mtt^yZ  
long[] nStartPos; //开始位置 8-3]Bm!  
long[] nEndPos; //结束位置 xX*I.saK  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 $3zs?Fd`  
long nFileLength; //文件长度 DXl3  
boolean bFirst = true; //是否第一次取文件 j[k&O)A{C
 
boolean bStop = false; //停止标志 A
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File tmpFile; //文件下载的临时信息 Z0s}65BR  
DataOutputStream output; //输出到文件的输出流 (4o_\&  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 4\a KC%5  
public SiteFileFetch(SiteInfoBean bean) throws IOException vmm#UjwF3  
{ BZP}0  
siteInfoBean = bean; pZUckQ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); n=WwB(}q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); vx62u29m  
if(tmpFile.exists ()) |RS9N_eRt  
{ +Kg
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bFirst = false; FY+0r67]  
read_nPos(); w4P?2-kB  
} !f[LFQD  
else FJomUVR.  
{ rg64f'+Eug  
nStartPos = new long[bean.getNSplitter()]; Y|FF ;[  
nEndPos = new long[bean.getNSplitter()]; q}p&<k  
} #kjN!S*=  
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/ E}L%OvE  
} jU.z{(s  
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public void run() g|ewc'y  
{ jI%v[]V  
//获得文件长度 ?XN=Er^
 
//分割文件 8'[g?  
//实例FileSplitterFetch }5 ^2g!M  
//启动FileSplitterFetch线程 ZmeSm& hQ_  
//等待子线程返回 _rt+OzZ*L  
try{ hAX@|G.  
if(bFirst) jLo(Uf  
{ kKL'rT6z  
nFileLength = getFileSize(); yIy'"BCxM  
if(nFileLength == -1) ~(bY-6z  
{ S^(OjS  
System.err.println("File Length is not known!"); w#mnab@  
} Q46^i7=  
else if(nFileLength == -2) 'ol8lIa.P  
{ W|h~&O  
System.err.println("File is not access!"); l\g>@b  
} G(gJtl  
else m_YXTwwx  
{ ~SUrbRaY>  
for(int i=0;i<nStartPos.length;i++) z#9Tg"8]  
{ EZnXS"z  
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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} n'*4zxAA  
for(int i=0;i<nEndPos.length-1;i++) S"hA@j  
{ )tYu3*'  
nEndPos = nStartPos[i+1]; " E+V>V+  
} 8*o*?1.  
nEndPos[nEndPos.length-1] = nFileLength; GPV=(}z  
} &iKy  
} =2v/f_  
z7TMg^9#  
Io_bS+  
//启动子线程 hK^(Y  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; z5.Uv/n\1  
for(int i=0;i<nStartPos.length;i++) v2eLH:6  
{ ayF+2(vch)  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ls[0X82F
 
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 3 UUOB.  
nStartPos,nEndPos,i); ;IyA"C(i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); En!X}Owh  
fileSplitterFetch.start(); }@6Tcn1  
} D!7-(3R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lRA=IRQ]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); s1 mKz0q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ((0nJJjz  
nEndPos = " + nFileLength); +/O3L=QyJ  
// fileSplitterFetch[nPos.length-1].start(); (U@Ks )  
_EPfeh;  
9r2l~zE  
//等待子线程结束 RvQa&r5l  
//int count = 0; @vyq?H$U;N  
//是否结束while循环 YoDL/  
boolean breakWhile = false; ri.}G  
phCItN;  
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while(!bStop) B|WM;Y^  
{ H@,h$$  
write_nPos(); !ZxK+Xqx[  
Utility.sleep(500); M02U,!di  
breakWhile = true; Q Ev7k  
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for(int i=0;i<nStartPos.length;i++) U80h0t%  
{ `:b*#@  
if(!fileSplitterFetch.bDownOver) vJ,r}$H3  
{ 8MQb5( !  
breakWhile = false; I9  (6  
break; t;HM  
} LNNwy:_ !  
} XXDLbT'J  
if(breakWhile) `;j@v8n$*  
break; HQkK8'\LP  
7l(GBr  
jw5ldC>U  
//count++; 9{*$[%d1  
//if(count>4) )k
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// siteStop(); 0RZ[]:(  
} Wn%b}{9Fb  
Cer&VMrQK  
<
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System.err.println("文件下载结束！"); mNA=<O;i)'  
} ;yu#Bs  
catch(Exception e){e.printStackTrace ();} =;Q:z^S  
} 3xIelTf*  
/7N&4FrG  
n }kn|To~  
//获得文件长度 /\.[@]  
public long getFileSize() \s?8}k  
{ jK-b#h.gL  
int nFileLength = -1; C'7DG\pr  
try{ !S~0T!afF  
URL url = new URL(siteInfoBean.getSSiteURL()); kqkTz_r|H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  CK+t6Gp  
httpConnection.setRequestProperty("User-Agent","NetFox"); xlcL;
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int responseCode=httpConnection.getResponseCode(); "5HSCl$r%  
if(responseCode>=400) oRZ98?Y\B  
{ <k?pnBI_  
processErrorCode(responseCode); vnN0o5  
return -2; //-2 represent access is error
[KL-T16  
} QHXA?nBX  
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+)hxYLk&I  
String sHeader; uf^HDrr<L  
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 ;kzjx%h  
for(int i=1;;i++) nIr:a|}[  
{ s*Nb=v.e9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); bj6;>Ezp3(  
//Utility.log(in.readLine()); )+Y"4?z~  
sHeader=httpConnection.getHeaderFieldKey(i); =P
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if(sHeader!=null) D7r&z?  
{ B:Y F|k}T  
if(sHeader.equals("Content-Length")) W{%X1::q$  
{ >PzZt8e  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); g=/!Ry=  
break; "Zfm4Nx"  
} M5a&eO  
} @O`T|7v  
else _\.4ofK(  
break; 7`j%5%q  
} %M3L<2  
} '}^qz#w   
catch(IOException e){e.printStackTrace ();} }Y^o("c(  
catch(Exception e){e.printStackTrace ();} k Nvb>v  
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9W0*|!tQ,+  
Utility.log(nFileLength); dS8ydG2  
9 JhCSw-<)  
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return nFileLength; k;B[wEW@  
} G6.lRaPu"m  
?b:Pl{?  
+T&YYO8>5  
//保存下载信息（文件指针位置） y/E:6w  
private void write_nPos() 7},oY""8  
{ i)$P1h
 
try{ jGi{:}`lB  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 0l3[?YtXc  
output.writeInt(nStartPos.length); $4mCtonP=  
for(int i=0;i<nStartPos.length;i++) $q*a}d[Q  
{ 80=LT-%#  
// output.writeLong(nPos); t`="2$NO  
output.writeLong(fileSplitterFetch.nStartPos); ^Ze(WE)  
output.writeLong(fileSplitterFetch.nEndPos); &~Y%0&F,&  
} qm"SN<2S*  
output.close(); ;mYZ@g%e  
} wfv\xHG  
catch(IOException e){e.printStackTrace ();} jEE!H/  
catch(Exception e){e.printStackTrace ();} 8_E(.]U  
} h% KEg667  
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,]@K,|pC)  
//读取保存的下载信息（文件指针位置） ;Xf1BG r  
private void read_nPos() c`/VYgcTqB  
{ 
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try{ 9%Tqk"x?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Zs]n0iwM'@  
int nCount = input.readInt(); BT&R:_:  
nStartPos = new long[nCount]; gxhdxSm=2  
nEndPos = new long[nCount]; -uxU[E  
for(int i=0;i<nStartPos.length;i++) R`Fgne$4  
{ Ph%{h"  
nStartPos = input.readLong(); *;)O'|  
nEndPos = input.readLong(); 3"zPG~fY{  
} a{L&RRJ  
input.close(); Yj'9|4%+|  
} I-}ms  
catch(IOException e){e.printStackTrace ();} zrqI^i"c  
catch(Exception e){e.printStackTrace ();} S]ayH$w\Q  
} z{|0W!nHJ  
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private void processErrorCode(int nErrorCode) %W8iC%~  
{ o">~ObR  
System.err.println("Error Code : " + nErrorCode); Ka6u*:/  
} I`(53LCqo  
8{=|<  
OPzudO  
//停止文件下载 4D2U,Ds  
public void siteStop() bf@g*~h@  
{ 78{9@\e"0  
bStop = true; f=k#o2  
for(int i=0;i<nStartPos.length;i++) n?nzm "g  
fileSplitterFetch.splitterStop(); v$0|\)E)  
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} Pjk2tf0j`  
} ]E-3/r$_cO  
//负责部分文件的抓取 xxyc^\$  
**FileSplitterFetch.java $cK}Tlq  
*/ mZ2CGOR  
package NetFox; :{N*Z}]  
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import java.io.*; [Q{\Ik  
import java.net.*; %VFoK
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public class FileSplitterFetch extends Thread { WKiP0~  
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tVO}{[U}  
String sURL; //File URL z
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long nStartPos; //File Snippet Start Position $1"gFg  
long nEndPos; //File Snippet End Position u3#+fn_  
int nThreadID; //Thread's ID <!g]q1  
boolean bDownOver = false; //Downing is over \wD/TLS}  
boolean bStop = false; //Stop identical CV\^gTPmx  
FileAccessI fileAccessI = null; //File Access interface :>.{w$Ln%  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1$eoW/8.  
{ F$DA/{.D  
this.sURL = sURL; bJetqF6n  
this.nStartPos = nStart; X5YOxMq  
this.nEndPos = nEnd; eM_;rMCr}  
nThreadID = id; j
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 `@ YV  
} sBB[u'h!  
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public void run() 'bJGQ[c  
{ Bkd$'
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while(nStartPos < nEndPos && !bStop) w") G:K  
{ )-_^vB  
~;3#MAG  
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try{ WI4<2u;  
URL url = new URL(sURL); g%l ,a3"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'o6}g p)  
httpConnection.setRequestProperty("User-Agent","NetFox"); ",3v%$>  
String sProperty = "bytes="+nStartPos+"-"; 6w7;  
httpConnection.setRequestProperty("RANGE",sProperty); Nna.NU1  
Utility.log(sProperty); /^AH/,p  
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InputStream input = httpConnection.getInputStream(); ppRmC,0f^  
//logResponseHead(httpConnection); g5@JA^\vZT  
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byte[] b = new byte[1024]; R1X'}#mU  
int nRead; sJ|pR=g)!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >9!J?HA  
{ mFF4qbe  
nStartPos += fileAccessI.write(b,0,nRead); ^T!Zz"/:  
//if(nThreadID == 1) ,_u7@Ix  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  I8?  
} .p! DVQ"a  
YK)m6zW5  
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Utility.log("Thread " + nThreadID + " is over!"); "G [Nb:,CR  
bDownOver = true; wHbkF#[:i  
//nPos = fileAccessI.write (b,0,nRead); w2.] 3QAZ  
} .qSDe+A  
catch(Exception e){e.printStackTrace ();} M!'d  
} _K9`o^g%PJ  
} ^AH[]sE_  
gLX<>|)*  
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//打印回应的头信息 04-_ K  
public void logResponseHead(HttpURLConnection con) HpEd$+Mz  
{ L]H'$~xx*  
for(int i=1;;i++) g8N"-j&@  
{ ksC_F8Q+  
String header=con.getHeaderFieldKey(i); aO(PVS|P  
if(header!=null) D+3?p  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xT"V9t[f  
Utility.log(header+" : "+con.getHeaderField(header)); QCW4gIp  
else D_d>A+  
break; xRD+!3  
} ;[::&qf  
} G`
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p qz~9y~
 
public void splitterStop() GK}
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{ M!J7Vj?Ps  
bStop = true; + f67y  
} ri{*\LV*@  
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vW=-RTRH  
} Qp:I[:Lr;  
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/* )$:1e)d  
**FileAccess.java 8X7??f1;Y  
*//文件访问(定位，写) -x+3nb|.  
package NetFox; G$>?UQ[  
import java.io.*; ekhv.;N~  
3:x(2 A  
23):OB>S`  
public class FileAccessI implements Serializable{ Q]K` p(  
,,{;G'R|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~A=zjkm  
RandomAccessFile oSavedFile; W<)P@_+-  
long nPos; 2|>\A.I|=  
9~Dg<wQ  
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public FileAccessI() throws IOException KQPu9f9  
{ @PvO;]]%  
this("",0); o^@"eG
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} 'GJB9i+a^  
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public FileAccessI(String sName,long nPos) throws IOException !kE5]<H\  
{ I_<VGUk  
oSavedFile = new RandomAccessFile(sName,"rw"); ]j3>=Jb;  
this.nPos = nPos; M-^I!C
 
oSavedFile.seek(nPos); bp?5GU&Uy  
} ln82pQD2Y~  
E
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public synchronized int write(byte[] b,int nStart,int nLen) KyyRHf5  
{ Y*c]C;%=  
int n = -1; uxf,95<g)  
try{ $.jGO!  
oSavedFile.write(b,nStart,nLen); X+;[Gc}(W  
n = nLen; ?Zb+xNKJ(  
} 3NpB1lgh&:  
catch(IOException e) q}P@}TE  
{ DO:,PZX  
e.printStackTrace (); J9mK9{#q  
} <T_3s\  
bT
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return n; XGSFG~d  
} 072C!F  
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} )=~&l={T  
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/* x0<;Rm [u=  
**SiteInfoBean.java .#yg=t1C  
*/ EsGu#lD2  
package NetFox; O@Aazc5K  
'3>;8(sl  
XKjrS 9:  
public class SiteInfoBean { Ljy797{f  
K{P-+(  
,clbD4  
private String sSiteURL; //Site's URL #kC~qux^  
private String sFilePath; //Saved File's Path  ~71U s  
private String sFileName; //Saved File's Name ,sL'T[tuiU  
private int nSplitter; //Count of Splited Downloading File Ce}`z L  
8Rj5~+5  
^@^8iZ  
public SiteInfoBean() ;\RVC7  
{//nSplitter的缺省值为5 c[Fc
3  
//default value of nSplitter is 5 G)7U&B  
this("","","",5); 60+zoL'  
} +_]Ui| l  
(]#^q8)]\9  
JH.XZM&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) P)Adb~r  
{ h[remR#3\  
sSiteURL= sURL; PF~@@j  
sFilePath = sPath; kk=n&M  
sFileName = sName; gQ\.|'%  
this.nSplitter = nSpiltter; GeR#B;{  
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} .RxTz9(  
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public String getSSiteURL() t=P+m  
{ c-$r
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return sSiteURL; \}b2oiY  
} =z# tr
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9+1{a.JO  
:=NXwY3~M  
public void setSSiteURL(String value) JQM_9
6\  
{ Usf@kVQ  
sSiteURL = value; TUp\,T^2  
} #<0Hvde  
B[uyr)$  
x$LCLP#$H  
public String getSFilePath() }3*<sxw7<  
{ -N' (2'  
return sFilePath; xGsOnY;  
} ~}_^$l8#-Q  
"^4*,41U  
#z(:n5$F  
public void setSFilePath(String value) %],BgLhS.  
{ )O[8 D  
sFilePath = value; ?IGp?R^j"  
} x@  =p  
~-'2jb*8  
']nI
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public String getSFileName() !BoGSI  
{ r8m}B#W7  
return sFileName; Wg}KQ6 6  
} >|SIqB<%:  
-m`|Sq  
8>C4w 5kF  
public void setSFileName(String value) H9T~7e+  
{ _A,_RM$Y  
sFileName = value; (>}1t!1  
} \:m~ +o$<-  
c^W;p2^  
q-z1ElrN7u  
public int getNSplitter() &y_t,8>5  
{ ?\\wLZ  
return nSplitter; 8-G )lyfj  
} Q6(~VvC-  
Y(,RJ&7  
2O kID WcM  
public void setNSplitter(int nCount) !~E/Rp  
{ IOFXkpKR  
nSplitter = nCount; ]xvA2!)Q  
} I$"Z\c8;  
} mP^B2"|q  
#eJfwc1JY  
?xaUWD  
/* ;2kQ)Bq"  
**Utility.java kQ=bd{a6  
*/ 6/;YS[jX  
package NetFox; +C`!4v\n  
1EV bGe%b  
nFni1cCD  
public class Utility { 7@{%S~TN  
^JY {<  
!{l% 3'2  
public Utility() ?c8~VQaQ  
{ ^y>V-R/N  
g=td*S  
M{L<aYe  
} 0L>3i8'  
7#)k-S!B  
//线程睡眠 H r:*p6  
public static void sleep(int nSecond) `ulQ C  
{ `v?hL
~  
try{ rai'x/Ut}+  
Thread.sleep(nSecond); qK'mF#n0#  
} s`x2Go  
catch(Exception e) e,sS.  
{ #.Dl1L/  
e.printStackTrace (); k)knyEUi  
}
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} 3Y P! B=  
C6gSj1  
//日志 6O/L~Z*t  
public static void log(String sMsg) ~;(\a@ _  
{ tM5(&cQ!d  
System.err.println(sMsg); z 4}"oQk:r  
} *$7^.eHfdd  
%ZRv+}z  
Z*Ffdh>*:&  
public static void log(int sMsg) G:e=9qTf  
{ yl>^QMmo  
System.err.println(sMsg); -, +o*BP  
} Yh]a4l0  
} bAt!S  
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iB0r+IbR  
/* U,b80%k:  
**TestMethod.java vT5GUO{5  
*/ D?ic~-&  
package NetFox; z\v  

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rE*yT(:w  
public class TestMethod { @IL@|Srs8  
y6am(ugE  
Q8HNST($?  
public TestMethod() 0^{Tq0Ri[  
{ ///xx/weblogic60b2_win.exe YEV;GFI1  
try{ f.ua,,P.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q!&:y7O8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); N_D=j6B  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }*XF- U  
fileFetch.start(); mTH[*Y,  
} (l][_6Q  
catch(Exception e){e.printStackTrace ();} FBNi (D  
]oix))'n  
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} ="T}mc  
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public static void main(String[] args) n}NUe`E_h  
{
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new TestMethod(); oItC;T  
} :V8oWMY  
} :TrP3wV_  
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