http断点续传简单实现（java)

/* +F)-n2Bi  
**SiteFileFetch.java PMytk`<`zw  
*/ V5K/)\#  
package NetFox; ,4Q4{Tx  
import java.io.*; ?62Im^1/  
import java.net.*; gQPw+0w  
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public class SiteFileFetch extends Thread { d=vuy   
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SiteInfoBean siteInfoBean = null; //文件信息Bean O t)}:oG  
long[] nStartPos; //开始位置 r:bJU1P1$s  
long[] nEndPos; //结束位置 Fx:38Ae  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~$u9  
long nFileLength; //文件长度 @R5^J{T  
boolean bFirst = true; //是否第一次取文件 T[SK>z  
boolean bStop = false; //停止标志 BH0m[9nU;  
File tmpFile; //文件下载的临时信息 hW#^H5?  
DataOutputStream output; //输出到文件的输出流 H{Ewj_L  
!i
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） u#Ig!7iUu  
public SiteFileFetch(SiteInfoBean bean) throws IOException D6L+mTN  
{ zP,r,ok7  
siteInfoBean = bean; uN)c!='I  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); GeP={lj  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1d< b\P0  
if(tmpFile.exists ()) 7FE36Ub9  
{ N (4H}2  
bFirst = false; TaRPMKk  
read_nPos(); EnWv9I<  
} bA)nWWSg=  
else ]VjvG};  
{ %D4)Bqr  
nStartPos = new long[bean.getNSplitter()]; nB`|VYmOP1  
nEndPos = new long[bean.getNSplitter()]; i%FC lMF  
} Eiu/p&ct  
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} 
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public void run() wY<s  
{ 'V?FeWp  
//获得文件长度 t1w]L  
//分割文件 Mc,|C)  
//实例FileSplitterFetch (vG*)a  
//启动FileSplitterFetch线程 9E
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//等待子线程返回 gO8d2?Oh  
try{ K;6#v%  
if(bFirst) E4% -*n  
{ gkd4)\9  
nFileLength = getFileSize(); <G}Lc  
if(nFileLength == -1) tY;<S}[@7w  
{ gHPJiiCv  
System.err.println("File Length is not known!"); ui>jJ(  
} $bG*f*w  
else if(nFileLength == -2) RxqNgun@  
{ r,JQR)l0@V  
System.err.println("File is not access!"); 5[4wN( )  
} _[R(9KyF0f  
else &za }THm  
{ q5_zsUR=  
for(int i=0;i<nStartPos.length;i++) ,,uhEoH  
{ (?Mn_FNE|  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {g.YGO  
} Sh(ys*y>  
for(int i=0;i<nEndPos.length-1;i++) q=W.82.U  
{ J:Fq ip  
nEndPos = nStartPos[i+1]; !An?<Sv$  
} ZR\N~.  
nEndPos[nEndPos.length-1] = nFileLength; NfClR HpVc  
} @4y?XL(n  
} i6WPf:#wr  
|J!mM<*K  
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//启动子线程 u:APGR^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; GKFRZWXdT  
for(int i=0;i<nStartPos.length;i++) U3N d\b'0  
{ nod&^%O"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]jD\4\M}  
nStartPos,nEndPos,i); ];k!*l
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); HX2u{
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fileSplitterFetch.start(); MAYb.>X#>  
} yzK<yvN  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <XLaJ;j  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); trDw|WA  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #A5X,-4G  
nEndPos = " + nFileLength); 4m<]qw
 
// fileSplitterFetch[nPos.length-1].start(); Z
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d3q%[[@  
{`D]%e
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//等待子线程结束 znE1t%V  
//int count = 0; yo[Sh6r/9b  
//是否结束while循环 S%MDQTM  
boolean breakWhile = false; `+n0a@BVB  
 `vH|P  
Pp }Z"  
while(!bStop) ^mq(j_E.  
{ =W7-;&  
write_nPos(); }@HgFM"  
Utility.sleep(500); ~+1mH  
breakWhile = true; 3*I\#Z4p1  
?+EAp"{j  
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for(int i=0;i<nStartPos.length;i++) x[lIib
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{ rY(7IX  
if(!fileSplitterFetch.bDownOver) \'Ca1[y@B  
{ `F/R:!v  
breakWhile = false; kFE9}0-  
break; [RKk-8I  
} _p8u &TZ  
} b4L7]&  
if(breakWhile) Z$J-4KN  
break; R|*0_!O:[  
)yyH_Ax2  
#~'d Y\&  
//count++; 'l(s)Oa{M:  
//if(count>4) h rSH)LbJ  
// siteStop(); }kt%dDU  
} [[c0
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System.err.println("文件下载结束！"); ?<jWEz=  
} =)Hu
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catch(Exception e){e.printStackTrace ();} .<?7c!ho  
} oo;<I_#07  

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//获得文件长度 HlX~a:.7  
public long getFileSize() 0p.MH~mx  
{ U+'zz#0qN  
int nFileLength = -1; *@bz<{!  
try{ gOnZ#  
URL url = new URL(siteInfoBean.getSSiteURL()); $yi:0t8t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0V-jOc  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ag2~q  
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int responseCode=httpConnection.getResponseCode(); dBA&NW07  
if(responseCode>=400) 1\,k^
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{ .WKJ37od  
processErrorCode(responseCode); (b~l.@xh  
return -2; //-2 represent access is error %
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} 0p[k7W u  
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String sHeader; ].d%R a:{  
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for(int i=1;;i++) dH5*%  
{ !S&/Zp  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
8y5"X"U  
//Utility.log(in.readLine()); D(Rr<-(  
sHeader=httpConnection.getHeaderFieldKey(i); PeIi@0vA  
if(sHeader!=null) UH0l8ixc  
{ ?i_
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if(sHeader.equals("Content-Length")) l'4<^q  
{ '*XIp:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =Pn"nkpML  
break; |WS@q'
  
} j~Fd8]@  
} ~Y f8,m  
else (PH7nW7  
break; Tv'1IE  
} } *)l  
} Z1
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catch(IOException e){e.printStackTrace ();} bBML +0a  
catch(Exception e){e.printStackTrace ();} %CnVK1u!  
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Utility.log(nFileLength); .9Oj+:n  
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return nFileLength; wQ+il6  
} 'LG\]h>+)  
tk-)N+M.  
#tUhul/O  
//保存下载信息（文件指针位置） >pZ_  
private void write_nPos() q]f7D\ M  
{ yj'lHC  
try{ 6'mZM=d  
output = new DataOutputStream(new FileOutputStream(tmpFile)); B>'J5bZsw  
output.writeInt(nStartPos.length); +%[, m&  
for(int i=0;i<nStartPos.length;i++) GGwwdB\x'  
{ L-U4 8 i  
// output.writeLong(nPos); 2\.23  
output.writeLong(fileSplitterFetch.nStartPos); `Ivt)T+n;  
output.writeLong(fileSplitterFetch.nEndPos); E$8-8[  
}  :Kyr}-  
output.close(); WxD$k3U  
} `lm'_~=`&  
catch(IOException e){e.printStackTrace ();} V6ECL6n  
catch(Exception e){e.printStackTrace ();} `_/1zL[  
} )40YA\V  
()8=U_BFz  
hiVDN"$$  
//读取保存的下载信息（文件指针位置） MW^FY4V1m  
private void read_nPos() aVVE2:M  
{ ~FI} [6Dd  
try{ _{^F8  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0V8G9Gj  
int nCount = input.readInt(); ( Ygy%O%  
nStartPos = new long[nCount]; d_:tiHw$  
nEndPos = new long[nCount]; ^cW{%R>XY  
for(int i=0;i<nStartPos.length;i++) N0D5N(kH%  
{ |1!|SarM{B  
nStartPos = input.readLong(); A ?~4Pe  
nEndPos = input.readLong(); V#1v5mWVx  
} t':*~b{V@7  
input.close(); N/0Q`cQ-  
} "lA$;\&  
catch(IOException e){e.printStackTrace ();} R. ryy  
catch(Exception e){e.printStackTrace ();} 2"xhFxoD7  
} 7~MWp4.  
U!"RfRD.<  
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private void processErrorCode(int nErrorCode) 3PzF^8KJ  
{ A}pe>ja  
System.err.println("Error Code : " + nErrorCode); xU.Ymq& 5  
} :/Y4I)'  
MS|1Q@S9  
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//停止文件下载 odcrP\S  
public void siteStop() .b*-GWx  
{ 
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bStop = true; ~fgS"F^7n  
for(int i=0;i<nStartPos.length;i++) |])Ko08*tE  
fileSplitterFetch.splitterStop(); y(K:,CI  
:e_yOT}}  
}2?-kj7  
} kP~ ;dJD  
} OJcI0(G  
//负责部分文件的抓取 rPW9lG  
**FileSplitterFetch.java ON_GD"  
*/ y3V47J2o  
package NetFox; x4_FG{AIu  
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import java.io.*; {}PBYXR  
import java.net.*; w$I$xup  
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public class FileSplitterFetch extends Thread { eY$Q}BcW  
w\.z-6G  
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String sURL; //File URL vi.q]$ohbV  
long nStartPos; //File Snippet Start Position oxqD/fY  
long nEndPos; //File Snippet End Position kObgo
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int nThreadID; //Thread's ID +Mh9Jf  
boolean bDownOver = false; //Downing is over \?.M1a[  
boolean bStop = false; //Stop identical &_c5C  
FileAccessI fileAccessI = null; //File Access interface
h|=&a0  
] i\a[3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Rh#TR"  
{ 2KmPZ&r  
this.sURL = sURL; OK9D
4 7X  
this.nStartPos = nStart; %8GY`T:^  
this.nEndPos = nEnd; (hX}O>  
nThreadID = id; W%7m3/d  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 cvf#^Cu   
} d~J4&w  
#6<9FY#  
cS1BB#N0  
public void run() FmRa]31W  
{ eqE%ofW  
while(nStartPos < nEndPos && !bStop) ^t\AB)(8  
{ KI
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^E8e
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try{ DV/P/1E  
URL url = new URL(sURL); 4 p(KdYc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wMB<^zZmv  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]jS+ItL@  
String sProperty = "bytes="+nStartPos+"-"; D~Y3\KP  
httpConnection.setRequestProperty("RANGE",sProperty); BqKh&m  
Utility.log(sProperty); U= PG0  
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3E361?ubM  
InputStream input = httpConnection.getInputStream(); Ci ? +Sl  
//logResponseHead(httpConnection); 7MT[fA8^  
^25[%aJI  
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byte[] b = new byte[1024]; @kLpK  
int nRead; 0:(@Y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) r`L$[C5I  
{ RSY{I
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nStartPos += fileAccessI.write(b,0,nRead); =ITMAC\  
//if(nThreadID == 1) ^kMgjS}R  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ZIx,?E+eJ  
} %!HmtpS  
?8X+)nU@  
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Utility.log("Thread " + nThreadID + " is over!"); )nS;]7pB@  
bDownOver = true; <c6C+OWT,  
//nPos = fileAccessI.write (b,0,nRead); 9)QvJ87e@7  
} ET`;TfqM  
catch(Exception e){e.printStackTrace ();} W/uaNp  
} Rd5r~iT
 
} @&]j[if(s  
>w?O?&Q$  
xxm1Nog6  
//打印回应的头信息 KwRO?G9&  
public void logResponseHead(HttpURLConnection con) H0s,tTK8  
{ ;ePmN|rq;  
for(int i=1;;i++) ?zNv7Bj  
{ SD6xi\8  
String header=con.getHeaderFieldKey(i); uM0z%z5b  
if(header!=null) 928szUo:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); d3(T=9;f2  
Utility.log(header+" : "+con.getHeaderField(header)); 81/Bn!  
else $_l@k=  
break; 3e:"tus~  
} k"V3FXC)  
} kO\(6f2|x  
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public void splitterStop() >b |l6#%  
{ ;/SM^&Y  
bStop = true; Ni GK|Z  
} BRV /7ao="  
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} 6pQ#Zg()vp  
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/* C 9,p-  
**FileAccess.java X1i6CEa<  
*//文件访问(定位，写) h&5H`CR[  
package NetFox; ID5?x8o#k  
import java.io.*; ~c`@uGw  
W<B8PS$  
3U@p  
public class FileAccessI implements Serializable{ ZQnJTS+Rd  
%dS7u$Rnh  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 sN7I~  
RandomAccessFile oSavedFile; F1)Q#ThF\  
long nPos; ^,b*.6t  
l@<^V N@  
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public FileAccessI() throws IOException OcMd'fwO  
{ EUe2<G  
this("",0); )"jG)c^1*  
} 9ToM5oQ  
0:h;ots'  
-^$CGRE6A  
public FileAccessI(String sName,long nPos) throws IOException <{YP=WYW  
{ /[GOs*{zB  
oSavedFile = new RandomAccessFile(sName,"rw"); ay'=M`uO_  
this.nPos = nPos; &.+[~2  
oSavedFile.seek(nPos); X!CLOHVAa  
} [t<^WmgtxL  
"(/|[7D)  
H[<"DP  
public synchronized int write(byte[] b,int nStart,int nLen) eP'e_E  
{ ^Cyx"s't  
int n = -1; //e.p6"8h  
try{ JQsS=m7Et  
oSavedFile.write(b,nStart,nLen); ?;|$R   
n = nLen; +sE81B  
} Gc4N)oq)}b  
catch(IOException e) wv ,F>5P  
{ H4KwbTT"+  
e.printStackTrace (); @p|[7'  
} `wB(J%w  
j"_V+)SD  
{;Mcor3  
return n; zEF3B  
} /Rx%}~x/m  
/I$g.f/#  
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} ]Vl*!,(i  
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#g{ZfO[#  
/* 5p94b*l  
**SiteInfoBean.java AvEJX0"\df  
*/ (LTm!"Q  
package NetFox; g}$]K!F  
;r^8In@6  
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public class SiteInfoBean { #?!)-Q%  
4zpprh+`K  
 Cg}cD.  
private String sSiteURL; //Site's URL `B :Ydf  
private String sFilePath; //Saved File's Path H`),PY2  
private String sFileName; //Saved File's Name 6;I&{9  
private int nSplitter; //Count of Splited Downloading File K}`.?6O  
/ta-jOcRH&  
*@cXBav/<  
public SiteInfoBean() !(uyqplTk  
{//nSplitter的缺省值为5 ;|soc:aH  
//default value of nSplitter is 5 ztgSd8GGE  
this("","","",5); lmj73OB3  
} , YTuZS  
< I8hy$+6  
opte)=]J  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >Ah [uM  
{ BGLJ>z
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sSiteURL= sURL; 3)atqM)i  
sFilePath = sPath; =MB[v/M59w  
sFileName = sName; SD8Q_[rY  
this.nSplitter = nSpiltter; 6Nj\N oS  
Rzj5B\+Rk(  
_+ oX9  
} xo6-Y=c8  
?bmP<(N5/  
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public String getSSiteURL() X*]uLgbl  
{ w/~,mzM"  
return sSiteURL; #J)sz,)(  
} <^ @1wg  
(pREo/T  
%%G2w63M  
public void setSSiteURL(String value) XBF#ILJ  
{ 3RXq/E  
sSiteURL = value; ht!o_0{~  
} }_@*,  
.,o=#  
wta\C{{  
public String getSFilePath() sn@gchO9s  
{ ">v76%>Z7  
return sFilePath; &UEr4RK;I  
} L1VUfEG-  
-,uTAk0+@  
-iR}kP|  
public void setSFilePath(String value) vCb3Ra~L`  
{ !0zbWB9  
sFilePath = value; #OqQD6  
} b" 1a7  
Z[)t34EY"  
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public String getSFileName() FWq+'GkSV  
{ re2M!m6k5  
return sFileName; g"EvMv&  
} sG=D(n1  
hxP%m4xF +  
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public void setSFileName(String value) f-F+Y`P  
{ EeIV6ug  
sFileName = value; Ur6UE2  
} A5S9F8Q/]  
^HgQ"dD <  
aHNR0L3$}{  
public int getNSplitter() f=+|e"i#p  
{ R9A8)dDz  
return nSplitter; |L}zB,  
} :.e`w#$7  
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|_
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public void setNSplitter(int nCount) AyKvh  
{ Hbu8gqu  
nSplitter = nCount; :hJHjh  
} Y,w'Op  
} cKJf0S:cx-  
QkS~~|0EI>  
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/* S96H`kedZo  
**Utility.java e/Wrm^]y  
*/ 4QC"|<9R  
package NetFox; AFE6@/'  

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public class Utility { ZKy)
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public Utility() 5b>-t#N,  
{ &|yQwNA*a"  
C))5,aX  
 ?QxI2J  
} p4mi\~Q  
,)/gy)~#  
//线程睡眠 p)6!GdT  
public static void sleep(int nSecond) H'KCIqo  
{ w0qrh\3du  
try{ rQmDpoy
=  
Thread.sleep(nSecond); p7et>;WRx  
} `_%UK=m  
catch(Exception e) qE B3Y54+  
{ TL&`Ywy  
e.printStackTrace (); g)0>J  
} tfB}U.  
} $HgBzZ7A2  
`9;0Y  
//日志 S!+c1q: ].  
public static void log(String sMsg) ot\  FZ  
{ SeuC7!q{  
System.err.println(sMsg); w O H{L  
} -R%T Dx  
o;'E("!<Z  
Lk%`hsv  
public static void log(int sMsg) grD[7;1~:)  
{ A]0A
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System.err.println(sMsg); f3yH4r?;w  
} Fl0(n #L  
} z<_&4)2{  
s!k7Wwj  
f^JiaU4 [  
/* YnR8mVo5Q  
**TestMethod.java Ibf~gr(j  
*/ 8Z&M}Llk  
package NetFox; j1zrjhXI  
ML_$/  
cNbH:r"Ay  
public class TestMethod { TWzlF>4N  
n[S-bzU^t  
}K.Rv(m  
public TestMethod() u+/Uc:XK)  
{ ///xx/weblogic60b2_win.exe [T |P|\M  
try{ J\@|c.ws  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); mkE_ a>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); P"(VRc6x  
SiteFileFetch fileFetch = new SiteFileFetch(bean); yj$$k~@  
fileFetch.start(); Fqt,VED  
} 3_bE12  
catch(Exception e){e.printStackTrace ();} Bd'X~Vj<  
+3yG8  
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} noNJ+0S  
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public static void main(String[] args) >&DC[)28  
{ c"O4=[N: ;  
new TestMethod(); F50l->F2&  
} T,a71"c  
} 6"Ze%:AZZ  
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