http断点续传简单实现（java)

/* lq`7$7-4  
**SiteFileFetch.java RCK*?\m5  
*/ )M[FPJP}  
package NetFox; 3w[uc~f  
import java.io.*; |@R/JGB^  
import java.net.*; &lzCRRnvt  
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public class SiteFileFetch extends Thread { U%VFr#  
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SiteInfoBean siteInfoBean = null; //文件信息Bean F60m]NUM)c  
long[] nStartPos; //开始位置 KqaEHL  
long[] nEndPos; //结束位置
}PDtx:T-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 AtAu$"ue  
long nFileLength; //文件长度 L-q)48+^k  
boolean bFirst = true; //是否第一次取文件 %){/O}I]>  
boolean bStop = false; //停止标志 ?G&J_L=@Y  
File tmpFile; //文件下载的临时信息 Dp^=%F{t  
DataOutputStream output; //输出到文件的输出流 ~:_10g]r  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） XC/M:2$  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6B>*v`T:  
{ <FZ*'F*M  
siteInfoBean = bean; OMYbCy^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); NW21{}=4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )B~{G\jS  
if(tmpFile.exists ()) f|s,%AU"i  
{ ^QHgc_oDm  
bFirst = false; pMUUF5  
read_nPos(); y=SpIbn{  
} pm=s  
else UK@hnQU8`  
{ yB;K|MXy?  
nStartPos = new long[bean.getNSplitter()]; =3;! 5P  
nEndPos = new long[bean.getNSplitter()]; `VglE?M  
} vsI|HxpyC,  
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} iy_3#x5>  
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public void run() f=4q]y#& X  
{ 6"+bCx0:  
//获得文件长度 Zjc0R   
//分割文件 #.OCoc  
//实例FileSplitterFetch "88<{xL  
//启动FileSplitterFetch线程 _XI,z0(  
//等待子线程返回 2&o3OKt  
try{ jgYe\dinM  
if(bFirst) F22]4DLHO  
{ H}1XK|K3#H  
nFileLength = getFileSize(); "#%9dWy  
if(nFileLength == -1) k>\s6  
{ WO+>W+|N  
System.err.println("File Length is not known!"); (|y@ftr@  
} }~<9*M-P  
else if(nFileLength == -2) nqcD#HUv  
{ Et)j6xz/F  
System.err.println("File is not access!"); reoCyP\!!  
} 7V~ gqum  
else ?U~`'^@  
{ lOIf4  
for(int i=0;i<nStartPos.length;i++) -li;w tCS  
{ hN;$'%^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Thp!X/2O`  
} >-CNHb  
for(int i=0;i<nEndPos.length-1;i++) +/#Lm#*nu%  
{ $
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nEndPos = nStartPos[i+1]; ;|Rrtf9  
} ?SoRi</1  
nEndPos[nEndPos.length-1] = nFileLength; $*+UX   
} 6bbzgULl  
} [Ue"#w  
p,OB;Ncf/  
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//启动子线程 ,L(q/#p
  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +C=^,B!,  
for(int i=0;i<nStartPos.length;i++) 1-pxM~Y  
{ tW3Nry  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~\7peH%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), zids2/_*  
nStartPos,nEndPos,i); U {sT %G  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =l}XKl->  
fileSplitterFetch.start(); (n@&M!a  
} FWpb5jc)3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6 &MATMR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); W -5wjc  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", X]Ma:1+  
nEndPos = " + nFileLength); ItQ3|-^  
// fileSplitterFetch[nPos.length-1].start(); B%Z,Xjq  
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FS6ZPjG)  
//等待子线程结束 hKQg:30<  
//int count = 0; *Cx3bg*Gan  
//是否结束while循环 tWI4x3&2  
boolean breakWhile = false; Uv=hxV[7y  
|-vn,zpe  
(d=knoo7A  
while(!bStop) 1Qo2Z;h@  
{ R94ID@LF  
write_nPos(); uhr&P4EW  
Utility.sleep(500); t|k-Bh:x  
breakWhile = true; rqi|8gKY  
! d" i  
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for(int i=0;i<nStartPos.length;i++) 7|pF(sb0  
{ P&8QKX3 j^  
if(!fileSplitterFetch.bDownOver) #,\qjY  
{ 4-\gha  
breakWhile = false; vsCy?  
break; @:G#[>nKe  
} L]Dl}z  
} soB5sFt&]  
if(breakWhile) 9uA2M!~i2  
break; sQr |3}I(  
4.i< `'  
#p|7\Y  
//count++; 3Qoa?*  
//if(count>4) *bTR0U  
// siteStop(); tCP;IU$  
} p?4h2`P  
+Zo&c}  
H7R6Ljd?&S  
System.err.println("文件下载结束！"); p#fV|2'  
} K6; sxF  
catch(Exception e){e.printStackTrace ();} Ni)/L( &  
} g{$F;qbkO  
G' a{;3  
tGh!5EZ6`  
//获得文件长度 HCVMqG!  
public long getFileSize() I'T@}{h  
{ @G>Q(a*,  
int nFileLength = -1; "ll TVB  
try{ r4FGz!U  
URL url = new URL(siteInfoBean.getSSiteURL()); Umt?COc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4?cIn4}  
httpConnection.setRequestProperty("User-Agent","NetFox"); bG[)r  
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int responseCode=httpConnection.getResponseCode(); |c5r&oM&m  
if(responseCode>=400) ;bxL$1  
{ 8X2
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processErrorCode(responseCode); _^"0"<,  
return -2; //-2 represent access is error -H(\[{3{V  
} K#<cuHGC  
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String sHeader; u'Ua ++a\  
&KZr`"cT#  
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for(int i=1;;i++) dAj;g9N/h  
{ C@Fk  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0]^ke:(#  
//Utility.log(in.readLine()); ~^pV>>LX|  
sHeader=httpConnection.getHeaderFieldKey(i); ;p4|M  
if(sHeader!=null) ZpTT9{PT=:  
{ F8%.-.l)  
if(sHeader.equals("Content-Length")) 2W 9N-t21  
{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); tHV81F1J  
break;
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} 5t&;>-A'?'  
} Rr/sxR|0_  
else MehMhHY  
break; wnoL<p  
} V:vYS  
}
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catch(IOException e){e.printStackTrace ();} :#=XT9  
catch(Exception e){e.printStackTrace ();} h1`u-tc2x  
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Utility.log(nFileLength); )cd5iE:FO  
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return nFileLength; y.'5*08S0  
} %qf ?_2v  
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+)eI8o0#  
//保存下载信息（文件指针位置） P,/=c(5\}  
private void write_nPos() )FnJLd  
{ Y^~Dr|5%  
try{ 20XN5dTFT  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Z_qOQ%l  
output.writeInt(nStartPos.length); }b5If7  
for(int i=0;i<nStartPos.length;i++) OL
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{ [Q5>4WY
 
// output.writeLong(nPos); tEXY>=  
output.writeLong(fileSplitterFetch.nStartPos); Ckc4U. t|  
output.writeLong(fileSplitterFetch.nEndPos); FV->226o%  
} #nOS7Q#uW  
output.close(); }pzUHl>  
} =5jng.  
catch(IOException e){e.printStackTrace ();} ?UGA-^E1  
catch(Exception e){e.printStackTrace ();} (dh{Gk4=+  
} {!`0i  
3h-C&C  
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//读取保存的下载信息（文件指针位置） !jeoB  
private void read_nPos() !^:)zORYR  
{ E 9LKVs}  
try{ D[5Qd)PIL  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); wgb e7-{  
int nCount = input.readInt(); [aF^D;o  
nStartPos = new long[nCount]; mDT"%I"4j  
nEndPos = new long[nCount]; <:rbK9MIl  
for(int i=0;i<nStartPos.length;i++) X!vBD  
{ ^+m6lsuA  
nStartPos = input.readLong(); 1>BY:xZr  
nEndPos = input.readLong(); 0$~zeG"  
} S?k G|y  
input.close(); G(~ s(r{%I  
} L93&.d@m9  
catch(IOException e){e.printStackTrace ();} muc>4!Q  
catch(Exception e){e.printStackTrace ();} 6pHn%yE*  
} ~RRp5x _  
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private void processErrorCode(int nErrorCode) vCB0x:
/  
{ Y%B:IeF}  
System.err.println("Error Code : " + nErrorCode); n7r )wy
 
} bvK fxAih  
d 18>0R  
};z[x2l^  
//停止文件下载 &u@<0 1=  
public void siteStop() o'8`>rb  
{ TNHkHR[&  
bStop = true; #:yh2y7a%  
for(int i=0;i<nStartPos.length;i++) X?'v FC  
fileSplitterFetch.splitterStop(); (rM-~h6g  
}?0At<(d  
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} PSM~10l,  
} CSC sJE#4
 
//负责部分文件的抓取 *}hx9:9\B  
**FileSplitterFetch.java 9 ^G.]W]  
*/ iIe\mV  
package NetFox; $T)E
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import java.io.*; 2th>+M~A  
import java.net.*; /R2K3E#  
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public class FileSplitterFetch extends Thread { =%O@%v  
sSM^net0  
m|}};8  
String sURL; //File URL :UMtknV  
long nStartPos; //File Snippet Start Position oY#62&wk4  
long nEndPos; //File Snippet End Position M+mO4q6  
int nThreadID; //Thread's ID d'4^c,d  
boolean bDownOver = false; //Downing is over ^"g # !  
boolean bStop = false; //Stop identical ]W-7 U_  
FileAccessI fileAccessI = null; //File Access interface uTemAIp $u  
<)vjoRv  
]%RX\~Q.4  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException K|n$-WDG}  
{ UY
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this.sURL = sURL; 9&>)4HNd?  
this.nStartPos = nStart; ^,?dk![1Cv  
this.nEndPos = nEnd; uEK9  
nThreadID = id; eq|G\XJ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /ynvQ1#uA  
} >8pmClVvmR  
$<y10DfO  
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public void run() )@X `B d  
{ Vz"Ja  
while(nStartPos < nEndPos && !bStop) K,VN?t<h  
{ ww_gG5Fc$  
w4S0aR:yL  
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try{ UJqDZIvC  
URL url = new URL(sURL); NaR/IsN8%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8op,;Z7Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3M;[.b  
String sProperty = "bytes="+nStartPos+"-"; FXHcy:)}G  
httpConnection.setRequestProperty("RANGE",sProperty); {Q&@vbw'  
Utility.log(sProperty); ,r&:C48dI  
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InputStream input = httpConnection.getInputStream(); dKOW5\H'  
//logResponseHead(httpConnection); dW32
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/GzA89N(  
(Hr_gkGtM  
byte[] b = new byte[1024]; |Ew~3-u!  
int nRead; ^* xhbM;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) I$#B#w?!$r  
{ YPjjSi:#  
nStartPos += fileAccessI.write(b,0,nRead);
C&&*6E5  
//if(nThreadID == 1) $yZ(c#L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;W/K7}  
} \Bg;^6U  
),G?f {`!  
5pOb;ry")`  
Utility.log("Thread " + nThreadID + " is over!"); muAI$IRR  
bDownOver = true; 'w'PrM,:  
//nPos = fileAccessI.write (b,0,nRead); (5^bU<  
} 6vx0F?>_  
catch(Exception e){e.printStackTrace ();} Hcp)Q76X  
} F~N
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} A,tmy',d"  
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>O{U4_j@(  
//打印回应的头信息 ^!={=No]  
public void logResponseHead(HttpURLConnection con) H%!ED1zpA  
{ m.F \Mn  
for(int i=1;;i++) ZB+N[VJs)  
{ ST#OO!  
String header=con.getHeaderFieldKey(i); (XQBBt  
if(header!=null) [hLSK-K 9  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )zFPf]gz  
Utility.log(header+" : "+con.getHeaderField(header)); &8l"Dl  
else n/ \{}9  
break; ,qx;
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} B,@<60u  
} _TB,2 R  
;*3OkNxa3  
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public void splitterStop() JGJXV
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{ =F(fum;zH  
bStop = true; tWs ]Zd  
} tD G[}j  
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} E3pnu.;U:_  
mfYY?]A*+  
(<= &#e?  
/* .RI{\i`  
**FileAccess.java j k%MP6  
*//文件访问(定位，写) j{.P'5e@pZ  
package NetFox; $VWeo#b  
import java.io.*; J>I.|@W4  
j}0W|*  
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public class FileAccessI implements Serializable{ aV^wTs#2I  
8Z=d+}Gg<  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 //SH=>w2
 
RandomAccessFile oSavedFile; x@-bY  
long nPos; aoLYw 9  
g4NxNjM;  
}U)g<Kzh  
public FileAccessI() throws IOException >L\>Th{o  
{ EcBJ-j6d  
this("",0); _[yBwh  
} (+@ Lnz\  
^E)Kse.>  
&P+7U
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public FileAccessI(String sName,long nPos) throws IOException E%R^ kqqr  
{ >~;MQDU5*Y  
oSavedFile = new RandomAccessFile(sName,"rw"); <<43'N+  
this.nPos = nPos; nqG9$!k^t  
oSavedFile.seek(nPos); C'HW`rh.^  
} C%s+o0b  
uF xrv  
:
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public synchronized int write(byte[] b,int nStart,int nLen) /H_,1Fu|  
{ ~16QdwK  
int n = -1; 0K\Xxo.=  
try{ orGNza"A  
oSavedFile.write(b,nStart,nLen); 6$1d
d#  
n = nLen; ohK_~  
} >^cP]gGY  
catch(IOException e) 'baew8Q#  
{ \q2#ef@2  
e.printStackTrace (); CNC3">Dk~9  
} {-(}p+;z  
+*dG'U6  
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return n; }gk37_}X\I  
} 3Un{Q~6h  
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} rJ LlDKP-(  
}GIwYh/  
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/* `>M-J-J  
**SiteInfoBean.java m).S0  
*/ (=v :@\r  
package NetFox; ` u#'  
p0 @,-  
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public class SiteInfoBean { Nm{\?  
.ZuRH_pI  
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private String sSiteURL; //Site's URL Ls8@@b,t2  
private String sFilePath; //Saved File's Path )ZxDfRjL  
private String sFileName; //Saved File's Name Xb0$BAP  
private int nSplitter; //Count of Splited Downloading File nz72w_  
hE|Z~5\Y,>  
p.{M sn  
public SiteInfoBean() {H]xA3[]  
{//nSplitter的缺省值为5 h28")c.pH=  
//default value of nSplitter is 5 gyqM&5b  
this("","","",5); rToZN!q\S  
} kA`Z#yu  
/.Yf&2X\  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) iV h^;  
{ #fq%903=  
sSiteURL= sURL; ?hpT"N,hF9  
sFilePath = sPath; \#LkzN8  
sFileName = sName; yc4?'k!  
this.nSplitter = nSpiltter; -__RFxG  
9`83cL  
>FO4]  
} 3\x
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`
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public String getSSiteURL() sVk+E'q  
{ qPh @Bl3  
return sSiteURL; A1b</2  
} qJjXN+/D  
G?:{9. (  
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public void setSSiteURL(String value) BMubN   
{ N_dHPa  
sSiteURL = value; uvNLm]*  
} XRZj+muTZ  
1&zvf4  
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public String getSFilePath() ^?pf.E!F`  
{ ;[-OMGr]#  
return sFilePath; <evvNSE  
} {WBe(dc_%  
{FYWQ!L  
;E Z5/"T  
public void setSFilePath(String value) 9YpgzCx Z  
{ N$\'X<{  
sFilePath = value; eWKFs)C]  
} 2nNBX2o&_  
glMYEGz6p  
jZjWz1+  
public String getSFileName() o!R.QI^2VT  
{ r]e1a\)r  
return sFileName; B3x4sKs  
} t=,ZR}M1`  
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public void setSFileName(String value) L<t>o":o  
{ n$2IaE;v  
sFileName = value; u/wWP4'$J@  
} Hrjry$t/J  
&cZQ,o  
,;3bPjey  
public int getNSplitter() Ck:RlF[6C  
{ 2TFb!?/RQ  
return nSplitter; #&V7CYJ  
} '}4z=f`}  
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public void setNSplitter(int nCount) D4@).%  
{ r6.`9  
nSplitter = nCount;  H7`JqS  
} [Lck55V+Q  
} xq6 eu 9  
d#-scv}s5  
~]sj.>P  
/* nt 9LBea  
**Utility.java zd%n)jlwR  
*/ :B^YK].  
package NetFox; X;e=d+pw  
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public class Utility { Tu!2lHK;  
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+9^V9]{Vo  
public Utility() Vy.gr4Cm  
{ EZ,Tc;f=  
'CQ~ZV5  
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} yH=Hrz:<eM  
q8m{zSr  
//线程睡眠 WGmXq.  
public static void sleep(int nSecond) (vR9vOpJ  
{ F"-u8in`
 
try{ FTF`-}Hz  
Thread.sleep(nSecond); {[|je]3v  
} g~7x+cu0  
catch(Exception e) ftb .CPWI  
{ T!f+H?6  
e.printStackTrace (); VyMFALSe]h  
} xK*G'3Ge  
} D(;jv="/  
X-,mNvz  
//日志 \m xi8Z w  
public static void log(String sMsg) <<FBT`Y[  
{ {"dvU"y)\  
System.err.println(sMsg); B*OEG*t  
} lXT+OJF  
>
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public static void log(int sMsg) <`Xt?K  
{ ^P!(*k#T  
System.err.println(sMsg);  JT,[;  
} V}Ok>6(~  
} |e QwI&  
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/* *'-[J2  
**TestMethod.java We`6# \Z X  
*/ YigDrW  
package NetFox; E%b*MU  
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public class TestMethod { 9#>t% IF~  
MaS-*;BY,  
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public TestMethod() SG4
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{ ///xx/weblogic60b2_win.exe ?wi^R:2|j  
try{ )MWbZAI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); (rieg F  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); qNuBK6E#4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @e#{Sm  
fileFetch.start(); I&J>   
} #?h-<KQQ  
catch(Exception e){e.printStackTrace ();} S'_2o?fs  
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6/dP)"a('  
} q/h, jM  
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public static void main(String[] args) :|HCUZ*H(T  
{ ==Ah& ){4^  
new TestMethod(); t"$#KP<  
} ;%Zu[G`C  
} Z#t}yC%^d  
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