http断点续传简单实现（java)

/* RGg(%.  
**SiteFileFetch.java .DR<Te  
*/ ( Qcp{
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package NetFox; ~ ! 3I2  
import java.io.*; " '6;/N  
import java.net.*; qg!|l7e  
~j5x+yC  
#iWSDy  
public class SiteFileFetch extends Thread { R_68-WO  
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SiteInfoBean siteInfoBean = null; //文件信息Bean MH
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long[] nStartPos; //开始位置 n\5RAIg  
long[] nEndPos; //结束位置 x2z;6)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 W$rH"_@m  
long nFileLength; //文件长度 < hO /jB  
boolean bFirst = true; //是否第一次取文件 T/xp?Vq6/  
boolean bStop = false; //停止标志 K]|> Et`  
File tmpFile; //文件下载的临时信息 O.Iu6D  
DataOutputStream output; //输出到文件的输出流 :GW&O /Yo  
1_ C]*p  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） %1O[i4s:-  
public SiteFileFetch(SiteInfoBean bean) throws IOException H5]^ 6 HwX  
{ 2eC(Ijq[a  
siteInfoBean = bean; !V\Q<So<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); T G{k0cdOT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); t{FlB!jv  
if(tmpFile.exists ()) ;._7jFj.  
{ 8&~~j7p
,  
bFirst = false;
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read_nPos(); )m{Ye0!RD  
} A
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else $m+sNEAa  
{ U
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nStartPos = new long[bean.getNSplitter()]; x-<)\L&  
nEndPos = new long[bean.getNSplitter()]; gV`=jAE_  
} [],1lRYI9_  
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} t|!j2<e  
t" 7yNs(I  
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public void run() Nl9I*x^e  
{ 7&"n`@(.!  
//获得文件长度 }X_;X_\3;'  
//分割文件 T4 N~(Fi)  
//实例FileSplitterFetch R8UYP=Kp  
//启动FileSplitterFetch线程 mp?78_I)  
//等待子线程返回 3=$q  
try{ >sjhA|gXk  
if(bFirst) hL;8pE8  
{ !F4@KAv  
nFileLength = getFileSize(); 6"t;gSt4  
if(nFileLength == -1) L%$|^T=%  
{ E+tB&  
System.err.println("File Length is not known!"); N, *m
,  
} D?,#aB"  
else if(nFileLength == -2) M$d%p6Cv  
{ G4;3cT3'  
System.err.println("File is not access!"); aKlUX  
} ;?~$h-9)  
else 1q3( @D5~+  
{ R:AA,^Z  
for(int i=0;i<nStartPos.length;i++) 1>Dl\czn  
{ 5"]~oPK  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P"?FnTbv[  
} 7Wa?$6d  
for(int i=0;i<nEndPos.length-1;i++) [NIlbjYH  
{ ELjK0pE}-  
nEndPos = nStartPos[i+1]; #D9e$E(J^  
} 2gjGeM  
nEndPos[nEndPos.length-1] = nFileLength; zrv#Xa!O\  
} ^6P3%  
} 6ubL1K  
fr}Eaa-{^  
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//启动子线程 >'5_Y]h4m|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |*X*n*oI  
for(int i=0;i<nStartPos.length;i++) K+)%KP
 
{ zYv#:>C8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |Uk" {  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), q;D+ai  
nStartPos,nEndPos,i); F@!Td(r2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qG/fE'(j&  
fileSplitterFetch.start(); pdb1GDl0q  
} wpt='(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %?hsoj&k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m8JR@!t7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ty@=yA17  
nEndPos = " + nFileLength); gx:;&4AD  
// fileSplitterFetch[nPos.length-1].start(); ).HDru-2  
*tX{MSYW  
9Sq%s&  
//等待子线程结束 5P hX"7  
//int count = 0; <U9/InN0[  
//是否结束while循环 EQIo5  
boolean breakWhile = false; {"H2 :-t<  
1?Aga,~k:a  
ph|ZG6:
  
while(!bStop) Ei3zBS?J)  
{ ia{c  
write_nPos(); NLe}Jqp  
Utility.sleep(500); %=<IGce  
breakWhile = true; (9mMkU=  
lE ;jCN  
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for(int i=0;i<nStartPos.length;i++) '[(nmx'yVJ  
{ Gy Qm/I  
if(!fileSplitterFetch.bDownOver) +wk`;0sA  
{ N_Af3R1_  
breakWhile = false; ^, i>'T
 
break; F'?I-jtI  
} ;C/bJEgdd  
} +~U=C9[gj  
if(breakWhile) uH^PQ  
break; Hv<'dt$|  
5;TuVU.8Q  
x2#qg>`l  
//count++; s&{Qdf  
//if(count>4) Lj%{y.Rj  
// siteStop(); q 'a  
} 5NXt$k5  
qG9+/u)\  
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System.err.println("文件下载结束！"); 0ZPV'`KGp  
} 9kY[j2,+  
catch(Exception e){e.printStackTrace ();} 8g7,2f/ }  
} kK~IwA  
?vGffMm  
do>
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//获得文件长度 ?68uS;  
public long getFileSize() :Ze+%d=  
{ :y,v&Kk#T  
int nFileLength = -1; 8Chu"PM%-J  
try{ Ei@M$Fd  
URL url = new URL(siteInfoBean.getSSiteURL()); I5);jgb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); m>e3vu  
httpConnection.setRequestProperty("User-Agent","NetFox"); dYojm1MQ  
;}.Kb
 
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int responseCode=httpConnection.getResponseCode(); rp:wQH7  
if(responseCode>=400) <B&R6<]T  
{ k6?cP0I)5  
processErrorCode(responseCode); VzRx%j/i  
return -2; //-2 represent access is error j%*7feSNC  
} 7/X"z=Q^|  
:PnSQjV:  
8C.!V =@\  
String sHeader; 6j8<Q 2  
jUjr6b"  
!m{2WW-  
for(int i=1;;i++) 9-bG<`v\E  
{ H.O(*Q=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [H"#7t.V-~  
//Utility.log(in.readLine()); )Z@-DA*Q-  
sHeader=httpConnection.getHeaderFieldKey(i); g"!\\:M  
if(sHeader!=null) -lRhz!E]  
{ [~k]{[NJ  
if(sHeader.equals("Content-Length")) (%Oe_*e}Y  
{ ^2M!*p&h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ~j@UlP  
break; <-jGqUN_I  
}
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} /k"hH\Pp  
else 8!h'j  
break; ._p""'Sa  
} \w)?SVp  
} 76#.F  
catch(IOException e){e.printStackTrace ();} *"G8  
catch(Exception e){e.printStackTrace ();} N^elVu4 K  
d\XRUO[  
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Utility.log(nFileLength); ^ZQCIS-R  
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return nFileLength; eZO9GMO  
} s5Fr)q// !  
FyEDt@J  
%N~CvN@T  
//保存下载信息（文件指针位置） VVrwOoCN  
private void write_nPos() n'64;J5  
{ Q59/ex  
try{ BxX$5u  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hZNEv|  
output.writeInt(nStartPos.length); Plz-7fy33  
for(int i=0;i<nStartPos.length;i++) qCJ=Z  
{ ~Y/z=^  
// output.writeLong(nPos); oG_~3Kt  
output.writeLong(fileSplitterFetch.nStartPos); ~B@}R  
output.writeLong(fileSplitterFetch.nEndPos); cq^sq1A:  
} wt7.oKbW  
output.close(); X
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} 12r` )  
catch(IOException e){e.printStackTrace ();} 4NVgOr
:  
catch(Exception e){e.printStackTrace ();} &?$\Y,{  
} Cals?u#U=  
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//读取保存的下载信息（文件指针位置） 2uo8jF.h  
private void read_nPos() f Lk"tW  
{ ~{ .,8jE  
try{ [w%#<5h  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); W:ixzpQ  
int nCount = input.readInt(); pa] TeH  
nStartPos = new long[nCount]; -v*x
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nEndPos = new long[nCount]; \FI^
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for(int i=0;i<nStartPos.length;i++) ^~I @ spR4  
{ X"J%R/f  
nStartPos = input.readLong(); iE{Oit^aG  
nEndPos = input.readLong(); `03<0L  
} +I
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input.close(); >1XL;)IL>  
}
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catch(IOException e){e.printStackTrace ();} x9*ys;~w  
catch(Exception e){e.printStackTrace ();} Rc7.M"wzjX  
} mahi7eU P  
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private void processErrorCode(int nErrorCode) T^.{9F]*S  
{ $wXih#7  
System.err.println("Error Code : " + nErrorCode); fle0c^=  
} \2eFpy(  

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)n7)}xy#z  
//停止文件下载 j];1"50?  
public void siteStop() n^Au*'  
{ 7dhn'TW  
bStop = true; k <}I<Or  
for(int i=0;i<nStartPos.length;i++) `
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fileSplitterFetch.splitterStop(); qi[(*bFK7  
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} s#Q_Gu  
} LsotgQ8   
//负责部分文件的抓取 >\-3P$  
**FileSplitterFetch.java bG1 ofsU  
*/ 3&'R1~Vh  
package NetFox; Cs;<'[_?YO  
NQ3|\<Wt  
i~AJ.@ #  
import java.io.*; AuM:2N2  
import java.net.*; L(Rorf~V  
~g96o81V  
j)<[j&OWw  
public class FileSplitterFetch extends Thread { 1(F
'~i|5  
NFM-)Z57  
Pb=rFas*C  
String sURL; //File URL [b pwg&Oo  
long nStartPos; //File Snippet Start Position pgfu+K7?w  
long nEndPos; //File Snippet End Position {G]`1Q1DR  
int nThreadID; //Thread's ID &*c'uNw  
boolean bDownOver = false; //Downing is over Bzm.X=U:  
boolean bStop = false; //Stop identical 8I {56$  
FileAccessI fileAccessI = null; //File Access interface H!^C
2  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4}PeP^pj  
{ K+t];(  
this.sURL = sURL; 0wYiu  
this.nStartPos = nStart; n%8#?GC`  
this.nEndPos = nEnd; V'$oTZ`  
nThreadID = id; m4\g o  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 oYGUjI  
} )da:&F -  
t)`+d=P  
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public void run() Fj48quW1\P  
{ FRD<0o/`  
while(nStartPos < nEndPos && !bStop) fzOMX z  
{ *@=fq|6l 2  
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try{ !}C4{Bgt*  
URL url = new URL(sURL); _fe0,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C
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httpConnection.setRequestProperty("User-Agent","NetFox"); I[a%a!QO  
String sProperty = "bytes="+nStartPos+"-"; [j1^$n 8V  
httpConnection.setRequestProperty("RANGE",sProperty); mKMGdN~  
Utility.log(sProperty); |4LQ\'N&  
012:BZR  
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InputStream input = httpConnection.getInputStream(); O\:;q*]
 
//logResponseHead(httpConnection); lP-kZA!  
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byte[] b = new byte[1024]; xBt4~q;#sE  
int nRead; xg4T` ])  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {!>E9Px  
{ |'!7F9GP  
nStartPos += fileAccessI.write(b,0,nRead); .Lp Nm'=R  
//if(nThreadID == 1) e*6U |+kJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +KYxw^k}"7  
} Udg& eEF  
/6A:J]Q_  
2M5*bNU_:  
Utility.log("Thread " + nThreadID + " is over!"); WCWSLEAza  
bDownOver = true;
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//nPos = fileAccessI.write (b,0,nRead); u>j5`OXo  
} DPR;$yV  
catch(Exception e){e.printStackTrace ();} z;``g"dSw  
} [Ja(ArO3|[  
} ,$ho2R),Fn  
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ye56-T  
//打印回应的头信息 Kn3YI9  
public void logResponseHead(HttpURLConnection con) $&c<T4$d  
{ #xD&z^o  
for(int i=1;;i++) Jq=X!mTd.  
{ A;b=E[iv  
String header=con.getHeaderFieldKey(i); p,!fIx  
if(header!=null) V_7Y1GD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); zLE>kK  
Utility.log(header+" : "+con.getHeaderField(header)); 5n-9#J$  
else R*zBnHAb!  
break; @|jKO5Y  
} cS. 7\0$  
} ^M[-K`c}  
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public void splitterStop() w50.gr7  
{ OYQXi  
bStop = true; ?*(r1grHl  
} ;Hz`0V  
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} Xq} n^W  
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/* KY;uO 8Te  
**FileAccess.java ,'/HcF?yf  
*//文件访问(定位，写) IF,i^,  
package NetFox; %5( EkP  
import java.io.*; .Bm^3A  
#VP-T; Ahe  
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public class FileAccessI implements Serializable{ ;C7BoHB9  
.x\/XlM  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6:SK{RSURC  
RandomAccessFile oSavedFile; ;p?42rCIcl  
long nPos; !HT>  
%B*<BgJ;4F  
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public FileAccessI() throws IOException J7 Oa})-+'  
{ y^0HCp{  
this("",0); >b/k|?xP  
} rH [+/&w5  
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public FileAccessI(String sName,long nPos) throws IOException 2Mv)0%,c  
{ cP$wI;P  
oSavedFile = new RandomAccessFile(sName,"rw"); )- Wn'C'Z  
this.nPos = nPos; !=k*hl0h  
oSavedFile.seek(nPos); k*zc5ev}  
} >F LdI  
`W.vW8!#  
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public synchronized int write(byte[] b,int nStart,int nLen) 3.GdKP.%  
{ `CTkx?e[  
int n = -1; ]ouUv7\  
try{ )edU <1P  
oSavedFile.write(b,nStart,nLen); 945 |MQPn  
n = nLen; 8as$h*Wh  
} JaB tX'  
catch(IOException e) OoU'86)  
{ OLd$oxKR  
e.printStackTrace ();  8E.5k@  
} h!X'SGK  
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return n; m,"cbJ /  
} nf+"vr}1  
)U/@J+{{  
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} w;h\Y+Myyk  
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/* I1}{~@  
**SiteInfoBean.java EFT02#F_f  
*/ ,*O{jc`(  
package NetFox; b'Nvx9=W  
ki][qvXJ  
>8Yrmq  
public class SiteInfoBean { jP6oJcZ  
VK@i#/jm  
3gfV0C\  
private String sSiteURL; //Site's URL hjm.Ath  
private String sFilePath; //Saved File's Path (Db*.kd8,  
private String sFileName; //Saved File's Name VUg~[  
private int nSplitter; //Count of Splited Downloading File d9Ow 2KrC  
>R'VY "\  
19YJ`(L`x  
public SiteInfoBean() VgC9'"|  
{//nSplitter的缺省值为5 ;29XvhS8  
//default value of nSplitter is 5 D+vl%(g  
this("","","",5); |WwFE|<  
} dBD4ogo1  
\qK}(xq[  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8d*<Aki?;  
{ KWuj_.;  
sSiteURL= sURL; xa%ktn  
sFilePath = sPath; v2uS6  
sFileName = sName; oJz:uv8Pe.  
this.nSplitter = nSpiltter; JNA}EY^2I.  
w|UKMbRMU]  
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} 0Ts_"p  
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public String getSSiteURL() ~sU! 1  
{ V n!az}  
return sSiteURL; 5 xzB1n8  
} }FdcbNsP  
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public void setSSiteURL(String value) FoelOq6  
{ qKb-aP-  
sSiteURL = value; !kk %;XSZ  
} gm%bxr@X~  
3lrZ-k+S{  
>|o9ggL`J5  
public String getSFilePath() fKK-c9F  
{ Xe^=(| M  
return sFilePath; A%2M]];%X  
} !6fpMo  
=D"63fP1  
)V =K#MCK  
public void setSFilePath(String value) m^u&g&^  
{ kjKpzdbD  
sFilePath = value; JgjL$n;F  
} dmMr8-w  
#*aGzF  
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public String getSFileName() A **
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{ <cS7L0h  
return sFileName; ah$7 Oudj  
} 1#X=&N  
:@807OYzy  
kG7,1teMk  
public void setSFileName(String value) $(mdz)Cfy  
{ =&g}Y  
sFileName = value; aD3F!Sn  
} v]Q_  
(,9cCnvmYU  
Ch&]<#E>`  
public int getNSplitter() XTXo xZ#w  
{ 3ijI2Zy  
return nSplitter; NCpn^m)Q}  
} 4a50w:Jy]  
YH+\rb_  
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public void setNSplitter(int nCount) X\)KVn`  
{ dcTM02kEh  
nSplitter = nCount; Am`A[rV0  
} >]08".ajS  
} r^tXr[}  
= (h;L$  
VKJ~ZIO@A  
/* F^
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**Utility.java xgw)`>p,W  
*/ Bst>9V&R  
package NetFox; T9v#Jb6  
qy(/   
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public class Utility { _*B~ESC0  
ysn[-l#  
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public Utility() p:>?  
{ +=04X F:  
3S|;yOl#X  
Dj&bHC5%  
} ?-&D'  
c5+lm}R?  
//线程睡眠 W%ZU& YBc  
public static void sleep(int nSecond) l*MUDT@M8\  
{ v?=VZ~`O(  
try{ P\0%nyOG(%  
Thread.sleep(nSecond); i1\ /\^  
} bc}OmPE  
catch(Exception e) SJ_cwYwI$  
{ naCI55Wx  
e.printStackTrace (); z"C(#Y56 x  
} u,9U0ua@;  
} &fhurzzAm  
]8nm9qmF<  
//日志 ?(UXK hs  
public static void log(String sMsg) .wn_e=lT  
{ tpzdYokh>  
System.err.println(sMsg); RKb3=}
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} m)2hl~o_  
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public static void log(int sMsg) BjJ
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{ j?)`VLZ  
System.err.println(sMsg); 4J|t}  
} KKJ[  
} w[[@&T\`  
BFu9KS+@)  
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/* CP#MNNvgrw  
**TestMethod.java R*#Q=_  
*/ ;//qjo  
package NetFox; )L("t  
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<?}g[]i  
public class TestMethod { 0|vWwZ
q  
3YF]o9  
~?+m=\  
public TestMethod() ~i#xjD5  
{ ///xx/weblogic60b2_win.exe l:/V%{sx  
try{ )%c)-c  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); lhODNWi
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +~]g&Mf6o  
SiteFileFetch fileFetch = new SiteFileFetch(bean); /kVc7LC  
fileFetch.start(); <4bo7XH  
} .]l2)O
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catch(Exception e){e.printStackTrace ();} OB@t(KNx*P  
go Z#  
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} ~H~4 fp b  
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;$;/#8`>  
public static void main(String[] args) p5BcDYOw`  
{ /YR$#&N2  
new TestMethod(); Qt39H@c|z~  
} S
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} +38P$Koz{r  
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