http断点续传简单实现（java)

/* \OVw  
**SiteFileFetch.java J5SOPG  
*/ PJ2m4ulY  
package NetFox; 7-MyiCt  
import java.io.*; kk ZM
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import java.net.*; b|u,[jEB  
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public class SiteFileFetch extends Thread { %h}3}p#4  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \ mg  
long[] nStartPos; //开始位置 ~' q&rvk`  
long[] nEndPos; //结束位置 15ImwQ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 (``|5;T\  
long nFileLength; //文件长度 3yu,qb'"&  
boolean bFirst = true; //是否第一次取文件 dF'oZQz  
boolean bStop = false; //停止标志 iCdq-r/r!6  
File tmpFile; //文件下载的临时信息 Z4{~  
DataOutputStream output; //输出到文件的输出流 :tp{(MF  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） G$1gk^G's  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5](,N^u{):  
{ #Kt5+"+7  
siteInfoBean = bean; v7mg8'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); uZ+vYF^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); BV eIj }  
if(tmpFile.exists ()) gPF5|% 3)  
{ "tz`@3,5dN  
bFirst = false; w%eEj.MI|i  
read_nPos(); iJzW3%E  
} c:,K{ZR  
else !CLL{\F  
{ vnH[D)`@  
nStartPos = new long[bean.getNSplitter()]; Vm%0436wOY  
nEndPos = new long[bean.getNSplitter()]; a]=j  
} 85#+_}#  
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} j]  
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public void run() ^i6`w_/  
{ @.l?V6g9T  
//获得文件长度 -bp7X{&  
//分割文件 6mC% zXR5  
//实例FileSplitterFetch V?4G~~F  
//启动FileSplitterFetch线程 *7K)J8kq  
//等待子线程返回 1VB{dgr  
try{ aKw7m={  
if(bFirst) _}Ec[c  
{ qQe23,x@5  
nFileLength = getFileSize(); @^^,VgW[  
if(nFileLength == -1) E\XD~
 
{ |1UJKJwX  
System.err.println("File Length is not known!"); 92g&,Wb  
} kXW$[R  
else if(nFileLength == -2) W)2ZeH*
  
{ T4x[ \v5d  
System.err.println("File is not access!"); ;{
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} -](3iPy}  
else NXdT"O=P  
{ N>',[4pJ|  
for(int i=0;i<nStartPos.length;i++) 6adXE  
{ rM)-$dZ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2IFEl-IB[  
} =
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for(int i=0;i<nEndPos.length-1;i++) %$zX a%A  
{ dwmZ_m.  
nEndPos = nStartPos[i+1]; |"k+j_/+  
} z>O=. Ku6  
nEndPos[nEndPos.length-1] = nFileLength; Tw!_=zy(Gw  
} )X5en=[)O  
} (
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//启动子线程 a'YK1QX  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |v= */
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for(int i=0;i<nStartPos.length;i++) YE1X*'4  
{ ( 2i{8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y1L7sH 9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0 A6%!h  
nStartPos,nEndPos,i); }y
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ZR@PqS+O/  
fileSplitterFetch.start(); N.|uPq$R  
} DeGcS1_?
 
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _sC kBDl-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "yc@_+"\+  
nEndPos = " + nFileLength); qb>mUS  
// fileSplitterFetch[nPos.length-1].start(); }XIUz|  
^3w >:4m  
|f<-lB[k  
//等待子线程结束 75RQ\_zDu  
//int count = 0; Hy#<f
Kz`!  
//是否结束while循环 P> ilRb  
boolean breakWhile = false; .dl4f"k  
`Y.Q{5Y  
\,yX3R3}.~  
while(!bStop) kac]Rh8vO  
{ 4 X6_p(  
write_nPos(); =Vi>?fWpn=  
Utility.sleep(500); AJR`ohh  
breakWhile = true; lb[\Lzdvmu  
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for(int i=0;i<nStartPos.length;i++) xGo,x+U*  
{ <ly.l]g  
if(!fileSplitterFetch.bDownOver) Evb %<`gd  
{ ewp&QH4  
breakWhile = false; Nt P=m @  
break; 2j*o[kAE  
} !;COFR  
} z.]  
if(breakWhile) aW7)}"j4  
break; O`Ge|4  
Q*
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+
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//count++; 8ZvozQE  
//if(count>4) wU)vJsOq  
// siteStop(); +
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} /GMT  
Mh*^@_h?  
}@avGt;v  
System.err.println("文件下载结束！"); }^}ep2^  
} Qr$Ay3#k  
catch(Exception e){e.printStackTrace ();} \KT}T  
} R,KoymXP  
LGF5yRk  
qo62!q  
//获得文件长度 M_EXA _  
public long getFileSize() 18kzR6(W  
{ N!W2O>VS  
int nFileLength = -1; zd^QG  
try{ T{Y;-m  
URL url = new URL(siteInfoBean.getSSiteURL()); Cz]NSG5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K!BS?n;  
httpConnection.setRequestProperty("User-Agent","NetFox"); >r
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Gs)2HR@>  
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int responseCode=httpConnection.getResponseCode(); fC^POLn[f  
if(responseCode>=400) !;~6nYY  
{ nK;c@!~pS  
processErrorCode(responseCode); EG3?C  
return -2; //-2 represent access is error S6bW?8`  
} cR"?EQ] `N  
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#JIh-h@  
String sHeader; Fi_JF;  
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for(int i=1;;i++) +-+%6O<C  
{ =&xNdc  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #gd`X|<Ch  
//Utility.log(in.readLine()); gdkQ h_\  
sHeader=httpConnection.getHeaderFieldKey(i); =TG[isC/F9  
if(sHeader!=null) CAvyS  
{ BA t0YE`-,  
if(sHeader.equals("Content-Length")) TSHQ>kP  
{ m C&*K  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \C.s%m  
break;
)mF;^3  
} vS_Ji<W~E  
} sGs_w:Hn  
else 7.N~e}p8  
break; \OX;ZVb?5  
} |Xv]s61  
} $m)[> C  
catch(IOException e){e.printStackTrace ();} )S2GPn7  
catch(Exception e){e.printStackTrace ();} 7U_OUUg  
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Utility.log(nFileLength); N5\]VCX  
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return nFileLength; !H[K"7w  
} `$N()P  
HE0@`(mCpa  
98x&2(N  
//保存下载信息（文件指针位置） d iGkwKj  
private void write_nPos() jdWA)N}kDG  
{  8%W(",nd  
try{ 1 /dy@'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); "ABg,
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output.writeInt(nStartPos.length); ir/-zp_  
for(int i=0;i<nStartPos.length;i++) (^4V]N&  
{ D?:AHj%gW  
// output.writeLong(nPos); ?<"H Io  
output.writeLong(fileSplitterFetch.nStartPos); c.;}e:)s  
output.writeLong(fileSplitterFetch.nEndPos); wz{]CQ7"  
} wW?/`>@  
output.close(); >^5UXQr  
} Bc^MZ~+ip  
catch(IOException e){e.printStackTrace ();} ,8^QV3  
catch(Exception e){e.printStackTrace ();} ym~  
} o+j~~P  
<+\ w.!  
|}Wm,J  
//读取保存的下载信息（文件指针位置） B(TE?[ #  
private void read_nPos() "g=g' W#  
{ ,q|;`?R;  
try{ e0; KmQjG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); SZ'2/#R>  
int nCount = input.readInt(); WQ>y;fi5/{  
nStartPos = new long[nCount]; U3UDA  
nEndPos = new long[nCount]; \2Atm,#4  
for(int i=0;i<nStartPos.length;i++) xYUC|c1Q9  
{ XzF-g*e  
nStartPos = input.readLong(); k9Xv@v  
nEndPos = input.readLong(); gcKXda(  
} 5U!yc7eBI/  
input.close(); n?=d)[]  
} fCa*#ME  
catch(IOException e){e.printStackTrace ();} }cPH}[$zF  
catch(Exception e){e.printStackTrace ();} +i0j3.  
} 8pZGu8  
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private void processErrorCode(int nErrorCode) 7I0[Ii  
{ Z>t,B%v  
System.err.println("Error Code : " + nErrorCode); )EhRqX9  
} P^Tk4_,0  
j{?ogFfi  
vl,Ff9  
//停止文件下载 %{*A@jQsg  
public void siteStop() -m"9v%>
Y  
{ 2:4:Q[{A  
bStop = true; JsZLBq*lP  
for(int i=0;i<nStartPos.length;i++) 9\J.AAk~/  
fileSplitterFetch.splitterStop(); <<5x"W(,  
LI`H,2Km  
[')C]YQb=  
} ,N`cH\  
} e*?
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//负责部分文件的抓取 eF%>5  
**FileSplitterFetch.java cFF'ygJ/  
*/ BV@xE  
package NetFox; ={
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io1hUZ  
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import java.io.*; QRL+-)DMc  
import java.net.*; iu9<]1k  
5tG\5  
s`63 y&Z[  
public class FileSplitterFetch extends Thread { |h6u%t2AY  
$YztLcn  
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String sURL; //File URL xb22:  
long nStartPos; //File Snippet Start Position EK=PY  
long nEndPos; //File Snippet End Position 7
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int nThreadID; //Thread's ID u>y/<9]q8  
boolean bDownOver = false; //Downing is over 1>IA9]D7  
boolean bStop = false; //Stop identical 
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FileAccessI fileAccessI = null; //File Access interface |K,[[D<R  
li7"{+ct  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException l =Is-N`  
{ ZtofDp5B  
this.sURL = sURL; }VDJ  
this.nStartPos = nStart; 5xIOi(3`Q  
this.nEndPos = nEnd; 'Xb
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nThreadID = id; N}rc3d#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Gjka %  
} !0DOj["  
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public void run() =_:Mx'7  
{ sb"h:i>O4  
while(nStartPos < nEndPos && !bStop) kmZ  U;Z  
{ vZJu=t  
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try{ Y0Bd[  
URL url = new URL(sURL); RJ0:O  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k,0lA#>  
httpConnection.setRequestProperty("User-Agent","NetFox"); L_{gM`UFc  
String sProperty = "bytes="+nStartPos+"-"; e]k\dj;,^%  
httpConnection.setRequestProperty("RANGE",sProperty); ,E3Ze*(U  
Utility.log(sProperty); ^EFVjGM  
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|Zm'!-_  
InputStream input = httpConnection.getInputStream(); <Dq7^,}#  
//logResponseHead(httpConnection); {wwkbc*  
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byte[] b = new byte[1024]; 7S.E,\Tws  
int nRead; sOb=+u$$9  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) m(rd\3d  
{ ^W*3S[-`g  
nStartPos += fileAccessI.write(b,0,nRead); eH' J  
//if(nThreadID == 1) 'eDV-cB  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %RD%AliO}K  
} ]7:*A7/!.  
t=BXuFiu  
:9Mqwgk,;3  
Utility.log("Thread " + nThreadID + " is over!"); )gPkL r  
bDownOver = true; !'f.g|a  
//nPos = fileAccessI.write (b,0,nRead); ,%4~ulKMn  
} W)p?cK`  
catch(Exception e){e.printStackTrace ();} rOA{8)jIa*  
}  Ds@nuQ  
} w3E#v&"=Y  
-![>aqWmj1  
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//打印回应的头信息 U{?#W  
public void logResponseHead(HttpURLConnection con) ibL   
{ JthW"{E  
for(int i=1;;i++) Q)L6+gW^  
{ W~Ae&gcn#  
String header=con.getHeaderFieldKey(i); v FWg0 $,  
if(header!=null) ]!'9Y}9a  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7j~}M(s
"  
Utility.log(header+" : "+con.getHeaderField(header)); S<O
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else i{2ny$55h  
break; P`TJqJiY~  
} CEl9/"0s6  
} G/y;o3/[Z  
E;-*LT&{  
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public void splitterStop() {}DoRpq=  
{ :{'%I#k2  
bStop = true; .X;DI<K  
} 7L !$hk  
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} r";;Fk#5  
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/* G^&P'*  
**FileAccess.java X|Rw;FY  
*//文件访问(定位，写) zn2Qp  
package NetFox; Dg'BlrwbR  
import java.io.*;
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public class FileAccessI implements Serializable{ Y wu > k  
:`<ME/"YE  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o3,}X@p  
RandomAccessFile oSavedFile; \SyG#.$  
long nPos; .Hm1ispq  
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public FileAccessI() throws IOException |$G|M=*LN  
{ =l+~}/7'Z  
this("",0); eiJ~1HX)  
} {jOV8SVL  
GFfZ TA  
3fd?xhWbN  
public FileAccessI(String sName,long nPos) throws IOException I'e`?H t  
{ %shCqS  
oSavedFile = new RandomAccessFile(sName,"rw"); 4o,G[Cf_  
this.nPos = nPos; vTq [Xe"  
oSavedFile.seek(nPos); 9`T2  
} qLa6c2o,  
yP0XA=,Y  
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public synchronized int write(byte[] b,int nStart,int nLen) HJ0Rcw%  
{ (Q F-=o  
int n = -1; A#Ne07d  
try{ ?4H>1Wk
b  
oSavedFile.write(b,nStart,nLen); K %.>o  
n = nLen; XkEE55#>|  
} jSdW?IH  
catch(IOException e) 3F?_{A  
{ !~fy".|x  
e.printStackTrace (); M+GtUE~"  
} F42?h:y8I  
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return n; f?W"^6Df  
} .M([
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} $*c!9Etl4  

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?F/)<r  
/* .kp3<.  
**SiteInfoBean.java Kdr}7#c  
*/ bA02)?L  
package NetFox; \%Lj !\  
@YHt[>*S  
DsCbMs=Y  
public class SiteInfoBean { tJ9gwx7Pg  
ZYs?65.  
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private String sSiteURL; //Site's URL k~IRds@G  
private String sFilePath; //Saved File's Path [Y-3C47  
private String sFileName; //Saved File's Name Z}yd`7  
private int nSplitter; //Count of Splited Downloading File St;@ZV  
SdNxSD$Q  
8)XAdAr  
public SiteInfoBean() ,)PpE&  
{//nSplitter的缺省值为5 ;uN&yj<}a  
//default value of nSplitter is 5 Zy=DY  
this("","","",5); ]/{iIS_  
} V@pUU~6R  
m_h$fT8 _  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }S 6h1X  
{ PasVfC@  
sSiteURL= sURL; C"R}_C|r)*  
sFilePath = sPath; &x
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sFileName = sName; YYF.0G}  
this.nSplitter = nSpiltter; 0S&C[I o6  
K96N{"{iI%  
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} Iwe  
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public String getSSiteURL() Svt%*j  
{ Z.,pcnaQb  
return sSiteURL; VYnB&3%DF  
} x{9$4d  
,jdTe?[*^  
52.%f+Oa  
public void setSSiteURL(String value) 349BQ5ND  
{ iiv`ji  
sSiteURL = value; C@!bd+'  
} m*vz   
?$.x%G+  
}%`f%/  
public String getSFilePath() .$a|&P=S  
{ kJpr:4;@_  
return sFilePath; UL]zuW/  
} }gKY_e3  
*r|Zbxf(  

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public void setSFilePath(String value) cK\'D  
{ %|B$y;q^3  
sFilePath = value; +zZ]Txb(  
} 5#mHWBGd7  
&Y1RPO41J  
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public String getSFileName() ta0;:o?/d  
{ X
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return sFileName; G6pR?K+  
} V)]lca  
CPcB17!  
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public void setSFileName(String value) J~)JsAXAI  
{ uvJmEBL:  
sFileName = value; V\=%u<f  
} #6mr'e1  
xtK}XEhG!  
6\USeZh  
public int getNSplitter() <jqL4!<  
{ y(X^wC  
return nSplitter; zICAV -&  
} DaqlL  
YM#J_sy@J.  
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public void setNSplitter(int nCount) zqxN/H]z  
{ ?MOjtAG0_~  
nSplitter = nCount; )i[K1$x2  
} uTvf[%EHW  
} N`O0jH{  
>N"=10  
zvwv7JtB  
/* }ISR +./+  
**Utility.java qRXHaQi@9  
*/ \m(>Q  
package NetFox; MbeK{8~E%l  
Z/LYTo$Bz  
9Us'Q{CD   
public class Utility { JPpNCC.b  
\`W8#fob  
j43i:c;F  
public Utility() rh T!8dTk  
{ Iv/h1j> H  
83F]d+n  
u.2^t:A  
} h<i.Z7F;tj  
p+V::O&&r  
//线程睡眠 \O)u' Bu  
public static void sleep(int nSecond) 2{S*$K[M  
{ .}Hs'co  
try{ ;ZTh(_7  
Thread.sleep(nSecond); p1s|JI  
} S2?)Sb`  
catch(Exception e) YGhHIziI  
{ x$KQ*P~q  
e.printStackTrace (); L#fSP  
} J
]|S0JC`  
} 3iw.yR  
g_)i)V  
//日志 F6"QsFG  
public static void log(String sMsg) =z'533C  
{ m Gx{Vpt  
System.err.println(sMsg); 4MRN{W6  
} 0OBwe6*  
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qWJap-hb  
public static void log(int sMsg) {
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{ %:y
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System.err.println(sMsg); OT#foP  
} aZ}z/.b]  
} (, $Lp0mB7  
n +dRAIqB  
5"w%  
/* Tx(=4ALY  
**TestMethod.java 7eG@)5Uy  
*/ ,.V=y%  
package NetFox; aZCxyoh+  
D!D}mPi[  
1~[GGl  
public class TestMethod { ~e=KBYDBu  
S9 @*g3  
}R`}Ey|{  
public TestMethod() =6BI[_0  
{ ///xx/weblogic60b2_win.exe hroRDD  
try{ P7!gUxcv9Y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \>+BvF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); X:W}S/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); r]&&*:  
fileFetch.start(); <n0j'P>1  
} cyWDtq  
catch(Exception e){e.printStackTrace ();} kS_37-;  
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} q[+V6n`Z5  
W |+&K0M  
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public static void main(String[] args) &sGLm~m#  
{ Zk0?=f?j  
new TestMethod(); ?{>5IjL)en  
} Job&qW9W`  
} EiWd =jDm  
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