http断点续传简单实现（java)

/* BG&XCn5g|  
**SiteFileFetch.java j:>_1P/  
*/ 9'" F7>d  
package NetFox; K`vc&uf  
import java.io.*; d94Le/E  
import java.net.*; tg~@(IT}j  
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public class SiteFileFetch extends Thread { qdCcMcGt  
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SiteInfoBean siteInfoBean = null; //文件信息Bean VZ3{$0 +  
long[] nStartPos; //开始位置 *"qS  
long[] nEndPos; //结束位置 1-=ZIHW  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 KkJrh@lk  
long nFileLength; //文件长度 wJAJ
/  
boolean bFirst = true; //是否第一次取文件 *DUP$@}k  
boolean bStop = false; //停止标志 =:"wU  
File tmpFile; //文件下载的临时信息 gVscdg5  
DataOutputStream output; //输出到文件的输出流 :w,#RcW  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） uB@~xQ_V  
public SiteFileFetch(SiteInfoBean bean) throws IOException WeiDg,]e$b  
{ b0|;v-v  
siteInfoBean = bean; BB9+d"Sq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \?_M_5Nb  
if(tmpFile.exists ()) o)2KQ$b>Q  
{ umo<9Y  
bFirst = false; eYQPK?jo  
read_nPos(); *ufVZzP(  
} o|cx?  
else ^h?]$P  
{ *,FU*zi  
nStartPos = new long[bean.getNSplitter()]; x@LNjlP  
nEndPos = new long[bean.getNSplitter()]; I<+i87=  
} EA``G8Vn>  
+bDBc?HZ{$  
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} H.)Y*zK0.  
% B^BN|r  
T B(K&3_D  
public void run() dJ(<zz+;b  
{ 1@:BUE;jZ  
//获得文件长度 Ys@OgdS@:  
//分割文件 Q)[DSM  
//实例FileSplitterFetch qokCVI-\  
//启动FileSplitterFetch线程 Liv.i;-qE  
//等待子线程返回 !)4'[5t"U  
try{ IQ\5!e  
if(bFirst) kxH` c  
{ ia#8 ^z  
nFileLength = getFileSize(); =1r
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if(nFileLength == -1) +4g H=6  
{  NIh?2w"\  
System.err.println("File Length is not known!"); IgyoBfj\d  
} 5q,ZH6\ {  
else if(nFileLength == -2) s1>d)2lX  
{ "&%Lhyt  
System.err.println("File is not access!"); &WKAg:^k)  
} d=C&b]  
else 5"9'=LV~  
{ BVzMgn;  
for(int i=0;i<nStartPos.length;i++) q}|_]R_y  
{ (.pi,+Ws  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); hA=}R.gi  
} J3QL%#  
for(int i=0;i<nEndPos.length-1;i++) i4}+n^oSYo  
{ 2|A?9aE%0  
nEndPos = nStartPos[i+1]; ~J![Nx/  
} qYP;`L}o#  
nEndPos[nEndPos.length-1] = nFileLength; J{U 171  
} 85:KlBe%+  
} +5x{|!Pn  
Y(&rlL(sPK  
Y !%2vOt  
//启动子线程 :|%1i>O  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; GS&I6  
for(int i=0;i<nStartPos.length;i++) ZJ8"5RW  
{ }eAV8LU  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 25Uw\rKeO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), eb>jT:  
nStartPos,nEndPos,i); lO
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <nU8.?\?~  
fileSplitterFetch.start(); H7 "r^s]D  
} e<$s~ UXv  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^{Fo,7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); RxE.t[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", B9dc*  
nEndPos = " + nFileLength); \GPTGi5A  
// fileSplitterFetch[nPos.length-1].start();  r m  
0uu)0:  
VHm.uL_UW  
//等待子线程结束 3Z}v%=5 "  
//int count = 0; (L*<CV  
//是否结束while循环 j6WDh}#  
boolean breakWhile = false; \Mzr[dI  
8ly6CP+^B  
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while(!bStop) muMd
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{ oU|_(p"e|  
write_nPos(); c'DNO~H  
Utility.sleep(500); Vg(FF"  
breakWhile = true; N u3B02D*  
?vP6~$*B  
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for(int i=0;i<nStartPos.length;i++) WK5B8u*<  
{ 9aBz%* xo  
if(!fileSplitterFetch.bDownOver) 8ZCR9%  
{ L{0\M`B-  
breakWhile = false; /@64xrvIl=  
break; VwKfM MI8  
} MZ?+I~@  
} TVF:z_M9  
if(breakWhile) Vn65:" O  
break; @<3kj R?j  
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//count++; ;+1ooeU  
//if(count>4) 2^%O%Pc  
// siteStop(); I9e3-2THfj  
} J1w,;T\55  
seVT|z  
}.1}yz^y  
System.err.println("文件下载结束！"); +;,X?E]g  
} %\L{Ud%7  
catch(Exception e){e.printStackTrace ();} RI<&cgWn+<  
} R*?!xDJ  
^Y%<$I
FG  
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//获得文件长度 vdh[%T,&  
public long getFileSize() V4&a+MJ@  
{ %]1te*_  
int nFileLength = -1; |]~],  
try{ |\xTcS|d  
URL url = new URL(siteInfoBean.getSSiteURL()); Aho-\9/x%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); mV0u:ws  
httpConnection.setRequestProperty("User-Agent","NetFox"); A;k#8&;  

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int responseCode=httpConnection.getResponseCode(); L|nFN}da  
if(responseCode>=400) M/,lP  
{ NHcA6y$Cz  
processErrorCode(responseCode); 6~l+wu<$  
return -2; //-2 represent access is error -p"}K~lt:  
} NiMsAI@j  
kQp*+ras  
)NK#}c~5  
String sHeader; 2FY]o~@  
=y>CO:^G%  
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for(int i=1;;i++) DyCkz"1S  
{ O^q~dda  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); T*g}^TEh  
//Utility.log(in.readLine()); 9 e|[9  
sHeader=httpConnection.getHeaderFieldKey(i); ] &SmeTe  
if(sHeader!=null) ?Yx2q_KZk  
{ yMD3h$w3a  
if(sHeader.equals("Content-Length")) CM6! 1 7  
{ [{>3"XJ'  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;U3K@_  
break; 1p$*N  
} =?_:h`}  
} gtIEpYN+  
else 5LZs_%#  
break; $wyPGok  
} QX42^]({;c  
} 2.^CIJc  
catch(IOException e){e.printStackTrace ();} "YAnGGx)LZ  
catch(Exception e){e.printStackTrace ();} >*uj )u%  
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Utility.log(nFileLength); ~
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return nFileLength; G.$KP  
} fQ
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I Bko"|e@  
mmG]|Cl@  
//保存下载信息（文件指针位置） F8#MI G   
private void write_nPos() m2&Vm~Py6b  
{ ^Nu j/  
try{ "3'a.b akw  
output = new DataOutputStream(new FileOutputStream(tmpFile)); J*_^~t  
output.writeInt(nStartPos.length); S<jiy<|`  
for(int i=0;i<nStartPos.length;i++) `sA xk  
{ `l6OQdB3W  
// output.writeLong(nPos); {?q`9[Z  
output.writeLong(fileSplitterFetch.nStartPos); ^/cqE[V~,  
output.writeLong(fileSplitterFetch.nEndPos); +p&zM3:9w  
} hi4-Z=pl  
output.close(); &M tF  
} [mj=m
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catch(IOException e){e.printStackTrace ();} *
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catch(Exception e){e.printStackTrace ();} !E|R3eX_  
} A'Z!l20_  
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//读取保存的下载信息（文件指针位置） x iz+R9p  
private void read_nPos() ?NvE9+n  
{ 4"\x#  
try{ @BPQ >  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O S#RCN*  
int nCount = input.readInt(); {:=W) 37U  
nStartPos = new long[nCount]; Aar]eY\  
nEndPos = new long[nCount]; ThkCKM  
for(int i=0;i<nStartPos.length;i++) K:% MhH-  
{ auqN8_+=  
nStartPos = input.readLong(); 7HQL^Q  
nEndPos = input.readLong(); 5!pNo*QK  
} bSn={O"M  
input.close(); :5'hd^Q  
} n*i&o;5  
catch(IOException e){e.printStackTrace ();} TtnJ u*  
catch(Exception e){e.printStackTrace ();} =T#hd7O`V  
} K4H2
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C~
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s];0-65)  
private void processErrorCode(int nErrorCode) _00}O+GLM4  
{ 6)W8HX~+  
System.err.println("Error Code : " + nErrorCode); wkx#WC  
} $at\aJ  
+t&+f7  
Z[l+{  
//停止文件下载 bKsEXS  
public void siteStop() `Y+R9bd  
{ 9Y2.ob!$}  
bStop = true; D=Nt0y  
for(int i=0;i<nStartPos.length;i++) x>,wmk5)  
fileSplitterFetch.splitterStop(); (kyRx+gA  
9G"4w`P  
:4x6dYNU  
} VKfpk^rU  
} L@jpid95  
//负责部分文件的抓取 g/WDAO?d  
**FileSplitterFetch.java e>6W ^ )  
*/ w~+\Mfz  
package NetFox; Jr%F#/  
8N$Xq\Da+>  
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import java.io.*; 7h2/8YUgQ  
import java.net.*; SUIu.4Mz  
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public class FileSplitterFetch extends Thread { B*E"yB\NV  
I[gPW7&S@  
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String sURL; //File URL smn(q)tt  
long nStartPos; //File Snippet Start Position v-^<,|vm2f  
long nEndPos; //File Snippet End Position GMkni'pV  
int nThreadID; //Thread's ID 8|$g"?CU  
boolean bDownOver = false; //Downing is over 9~2iA,xs  
boolean bStop = false; //Stop identical +?*.Emzl@  
FileAccessI fileAccessI = null; //File Access interface J5O/c,?g  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException C-@M|K9A'  
{ @[`]w
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this.sURL = sURL; A|@d{g  
this.nStartPos = nStart; k]P'D .  
this.nEndPos = nEnd; #c"05/=A  
nThreadID = id; YHke^Ind
 
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (CtRU  
} *a0#PfS[  
6 {F#_.  
F&^&"(H}  
public void run() 3RI6+Cgmn  
{ T~SkFZ  
while(nStartPos < nEndPos && !bStop) !>wu7u-  
{ a+CJJ3T-  
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try{ ~(NFjCUY?  
URL url = new URL(sURL); 1K)9fMr]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AAuwE&Gg  
httpConnection.setRequestProperty("User-Agent","NetFox"); cVarvueS  
String sProperty = "bytes="+nStartPos+"-"; O3dQno  
httpConnection.setRequestProperty("RANGE",sProperty); /UY'E<wBx  
Utility.log(sProperty); BT^=p  
V\Y,4&bI  
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InputStream input = httpConnection.getInputStream(); 4PR&67|AH_  
//logResponseHead(httpConnection); V?>&9D"m  

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byte[] b = new byte[1024]; F9(jx#J~t  
int nRead; !}c\u  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) a*_&[  
{ n$h+_xN  
nStartPos += fileAccessI.write(b,0,nRead); mi5bk>o  
//if(nThreadID == 1) /xr75|-8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `#r/L@QI  
} x>Dix1b:.  
.
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Utility.log("Thread " + nThreadID + " is over!"); c=a;<,Rzb  
bDownOver = true; : Q2=t!  
//nPos = fileAccessI.write (b,0,nRead); %kH,Rl\g  
} X'%BS  
catch(Exception e){e.printStackTrace ();} hY
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} 6Bd:R}yZP7  
} Uxe]T  
}dqOE-"I"n  
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//打印回应的头信息 }N,v&B  
public void logResponseHead(HttpURLConnection con) =i2]qj\  
{ '%rn-|)  
for(int i=1;;i++) e(OKE7  
{ _g D9oK  
String header=con.getHeaderFieldKey(i); vDR> Q&/K  
if(header!=null) p]toDy-}  
//responseHeaders.put(header,httpConnection.getHeaderField(header));
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Utility.log(header+" : "+con.getHeaderField(header)); |TJu|zv^  
else nDLiER;U  
break; %x}Unk  
} jH;L7
 
} 8u"C7} N_  
x #|t#N%  
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public void splitterStop()  (tT%rj!  
{ w*(1qUF#%  
bStop = true; ,w
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} =BV_?  
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} X)c0y3hk  
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/* s(=@J?7As  
**FileAccess.java AvuGAlP  
*//文件访问(定位，写) Iu;VFa  
package NetFox; 1pN8,[hyR7  
import java.io.*; k>E/)9%ep2  
wLg@BSC.  
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public class FileAccessI implements Serializable{ ZKB27D_vg>  
O31.\ZR2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 y>r^ MQ  
RandomAccessFile oSavedFile; N~(?g7  
long nPos; $UdFm8&  
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public FileAccessI() throws IOException \#"&S@%c  
{ fCv.$5  
this("",0); 7Fb!;W#X  
} nQfSQMg  
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public FileAccessI(String sName,long nPos) throws IOException Eqx|k-<a  
{ -t125)6I  
oSavedFile = new RandomAccessFile(sName,"rw"); mP_c-qD |  
this.nPos = nPos; """eU,"  
oSavedFile.seek(nPos); P4s,N|bs`  
} VlxHZ  
th{Ib@o  
i/,IG+4vI  
public synchronized int write(byte[] b,int nStart,int nLen) LcHe5Bv%  
{ v0pev;C  
int n = -1; /86PqKU(P  
try{ Y1{*AV6ev6  
oSavedFile.write(b,nStart,nLen); {iTA=\q2O  
n = nLen; ,mt=)Ac  
} j3/K;U/SGJ  
catch(IOException e) ;!H]&2`'(  
{ w?R#ly  
e.printStackTrace (); h$$i@IO0  
} MQo/R,F }  
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return n; j[:Iu#VR  
} 7x(z  
}#`-mRaU  
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} |'Ksy{lA  
/)XN^Jwa;m  
TK Ec^  
/* z?C&,mv
 
**SiteInfoBean.java )"Dl,Fig:/  
*/ 5 r&n  
package NetFox; VCvFCyAz  
$HFimU,V=0  
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public class SiteInfoBean { OZ Hfd7K4A  
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private String sSiteURL; //Site's URL W JG8E7  
private String sFilePath; //Saved File's Path :v8~'cZ  
private String sFileName; //Saved File's Name WCwM+D  
private int nSplitter; //Count of Splited Downloading File e]3b0`E  
9S<atMB  
ko`KAU<T_  
public SiteInfoBean() h`V#)Q  
{//nSplitter的缺省值为5 /jd.<r=_I  
//default value of nSplitter is 5 q,.@<sW
 
this("","","",5); xdrs
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} /"7_75 t  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #PA 9bM  
{ .=/TT|eMS  
sSiteURL= sURL; ZKoISuM  
sFilePath = sPath; n]v,cfn/=<  
sFileName = sName; WXJ%hA  
this.nSplitter = nSpiltter; E)Cdw%}
^  
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} 9wpV} .(  
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public String getSSiteURL() 9=p/'d8  
{ \CZD.2p#&  
return sSiteURL; ;;7:l,vy  
} lD@`xq.M;  
^y<8&ZFH  
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public void setSSiteURL(String value) :a'[4w  
{ +L|-W9"@3  
sSiteURL = value; "|<U`3y6  
} @ACq:+/Qc  
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2HF_kYZ  
public String getSFilePath() th`pf   
{ &W$s-qf".  
return sFilePath; L<[%tvV  
} sJ5Ws%q  
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Q> J9M`a  
public void setSFilePath(String value) V~"-\@  
{ rqz`F\A;%  
sFilePath = value; 0^>b=a  
} ,V.Bzf%=O  
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Q ?R3aJ  
public String getSFileName() f7oJ6'K  
{ #(G"ya  
return sFileName; TWSx9ii!M:  
} ANq3r(  
87yZd8+)  
<7Ry"z6g;  
public void setSFileName(String value) :fA|J!^b[  
{ PHxNo)  
sFileName = value; b&2N7%  
} %ZM"c  
I T?~`vi  
>Q[3t79^  
public int getNSplitter() lAJP X  
{ lkJ"f{4f  
return nSplitter; }}u16x}*n  
} xzz0uk5  
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sny$[!)  
public void setNSplitter(int nCount) #&K?N  
{ ob]j1gYb  
nSplitter = nCount; e3,@prr  
} <7_s'UAL!  
} r2T$ ;m.  
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/* !24PJ\~I  
**Utility.java u{LtyDnik  
*/ @K1'Q!S*  
package NetFox; RwUosh\W  
]\ t20R{z  
xiOAj"}
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public class Utility {  xq&r|el  
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public Utility() cy0j>-z  
{ (/KeGgkhv  
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} ^j7>Ul,  
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//线程睡眠 ^J'O8G$  
public static void sleep(int nSecond) T'!p{Fbg;  
{ VI]~uTV  
try{ sGG q~7  
Thread.sleep(nSecond); c!N#nt_<  
} = OzpI  
catch(Exception e) S/dj])g  
{ -+[~eqRB  
e.printStackTrace (); j937tn!Q  
} OV|n
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} T&'LQZM8  
U#:N/ts*(  
//日志 sKC(xO@L;`  
public static void log(String sMsg) T%4yPmY  
{ F},kfCFF  
System.err.println(sMsg); 'LYN{  
} {t|Q9
&  
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l ;S_J^S  
public static void log(int sMsg) 'EC0|IT)c  
{ .>1vN+  
System.err.println(sMsg); qtuT%?wT@Z  
} e5(c,,/  
} JA% y{Wb  
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0{/
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/* A3|2;4t  
**TestMethod.java :-$TD('F  
*/ ;H9 W:_ahE  
package NetFox; `
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qv[w 1;U"  
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public class TestMethod { J;ycAF~  
#vc!SI  
'p)DJUwt  
public TestMethod() rpc;*t+z  
{ ///xx/weblogic60b2_win.exe W9]0X  
try{ ni6zo~+W]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P MI?PC[;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \d3~kq3  
SiteFileFetch fileFetch = new SiteFileFetch(bean);
h+}{FB 29  
fileFetch.start(); Q.Y6  
} w$j6!z  
catch(Exception e){e.printStackTrace ();} _&[-< cu  
%qEp{i
tq  
r{f
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} 2OjU3z<J  
"
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public static void main(String[] args) u Yc}eMb  
{ O&sUPv  
new TestMethod(); ^!$=(jh.  
} n`!6EaD  
} 8mt#S  
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