http断点续传简单实现（java)

/* m4 4aKqw)  
**SiteFileFetch.java \UNw43EL  
*/ n'M}6XUw  
package NetFox; :+[
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import java.io.*; 9KAXc(-  
import java.net.*; 2RM0ca_F  
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public class SiteFileFetch extends Thread { 0|4XV{\qT$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Cu/w><h)  
long[] nStartPos; //开始位置 u
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long[] nEndPos; //结束位置 6J&L5E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 xY_/CR[,  
long nFileLength; //文件长度 rJ<v1Yb  
boolean bFirst = true; //是否第一次取文件 ZYL]|/"J9  
boolean bStop = false; //停止标志 _-^KqNyy  
File tmpFile; //文件下载的临时信息 ?]sj!7   
DataOutputStream output; //输出到文件的输出流 $e<3z6  

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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） a&y%|Gs^f  
public SiteFileFetch(SiteInfoBean bean) throws IOException @$~%C) %u  
{ jfgAI7;b  
siteInfoBean = bean; 4'X^YBm  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fmloh1{4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }|A%2!Q}  
if(tmpFile.exists ()) le8n!Dk(  
{ B-eYWt8s  
bFirst = false; L*L3;y|  
read_nPos(); N^`F_R1Z  
} L4Kkbt<x  
else E5 Y92vu  
{ AZtZa'hbkQ  
nStartPos = new long[bean.getNSplitter()]; fv`%w  
nEndPos = new long[bean.getNSplitter()]; >eJk)q
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} O{%y `|m  
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} %JiA,  
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public void run() <EpP;  
{ 9~u1fk{  
//获得文件长度 2&5"m;<  
//分割文件 @^%zh  
//实例FileSplitterFetch }HXNhv-K  
//启动FileSplitterFetch线程 4d6F4G4U  
//等待子线程返回 .eJ4F-V  
try{ 5z#>>|1>#  
if(bFirst) j;<;?IW  
{ a"hlPJlG  
nFileLength = getFileSize(); w9z((\5  
if(nFileLength == -1) mJWl#3  
{ 3pq&TYQU  
System.err.println("File Length is not known!"); ,D~C40f  
} 7eh}Je8  
else if(nFileLength == -2) e9N 1xB  
{ )LH nDx  
System.err.println("File is not access!"); TQbhK^]  
} eGnc6)x@C  
else cH"M8gP#  
{ R+, tn,<<  
for(int i=0;i<nStartPos.length;i++) wCc:HfmjJ  
{ [O(78n$$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8[}MXMRdb  
} .$S`J2Y  
for(int i=0;i<nEndPos.length-1;i++) ^=Up UB  
{ {v~&.|  
nEndPos = nStartPos[i+1]; J;'?(xO3\  
} }%_x T  
nEndPos[nEndPos.length-1] = nFileLength; G4AX8@;U  
} Bz!ddAvlK  
} /1Rm^s)2z  
I)DLnnQQ  
t~XwF(";  
//启动子线程 4z[Z3|_V  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; UHweV:(|T  
for(int i=0;i<nStartPos.length;i++) I@ }:} 8t  
{ RR^I*kRH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B2&fvv?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Wc03Sv&FZ  
nStartPos,nEndPos,i); AUxLch+"5K  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ':F{st>&H  
fileSplitterFetch.start(); ){R_o
5  
} uXu'I  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PS(9?rX#+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);
7P:0XML}  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b*r1Jn"h  
nEndPos = " + nFileLength); 8R8J./i.K  
// fileSplitterFetch[nPos.length-1].start(); nN/v7^^  
r'pFHX  
3"!2C,3c#  
//等待子线程结束 tSE6
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//int count = 0; <}N0y*m  
//是否结束while循环 #`v`e"  
boolean breakWhile = false; Xp
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%|oY8;0|A>  
while(!bStop) #j iQa"  
{ Yy>%dL  
write_nPos(); M_$pqVm  
Utility.sleep(500); pShSKRg  
breakWhile = true; GAtK1%nPD  
J'^BxN&  
{HvR24
#  
for(int i=0;i<nStartPos.length;i++) -5kq9Dy\,  
{ dg/7?gV  
if(!fileSplitterFetch.bDownOver) htlsU*x  
{ c*MjBAq  
breakWhile = false; RE!MX>sOEq  
break; Fov/?:f$  
} R 5bt~U  
} $:/y5zi  
if(breakWhile) !0*=z~  
break; pRUN[[L
 
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//count++; i LK8Wnrq  
//if(count>4) f+%J=Am  
// siteStop(); D\N-ye1LE  
} Qf7]t-Kp  
?VS {,"X  
'rp(k\pY  
System.err.println("文件下载结束！"); ^X"G~#v=q  
} I2YQIY+  
catch(Exception e){e.printStackTrace ();} X
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} bN<c5  
{B?%r[nW  
.I {X  
//获得文件长度 `H+ 7Hj  
public long getFileSize() /PQg>Pa85  
{ ,^:Zf|V  
int nFileLength = -1; Qaq{UW
 
try{ V*U"OJ%  
URL url = new URL(siteInfoBean.getSSiteURL()); REQ2pfk0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G*\wu&7!  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~9h6"0K!  
ElqHZ$a?  
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int responseCode=httpConnection.getResponseCode(); qSkt }F%'  
if(responseCode>=400) iDp]lu  
{ *z` {$hc  
processErrorCode(responseCode); @bfaAh~   
return -2; //-2 represent access is error &=X1kQG  
} 3(E"$Se,f  
"*kWM  
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String sHeader; IOvYvFUUJ  
7{v0K"E{  
7&'^H8V  
for(int i=1;;i++) K34ca-~  
{ im*QaO%a4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); PPPRO.y  
//Utility.log(in.readLine()); Vu^J'>X  
sHeader=httpConnection.getHeaderFieldKey(i); hk}M'  
if(sHeader!=null) HP*x?|4  
{ w+2:eFi=/  
if(sHeader.equals("Content-Length")) uhQ
3  
{ rS>njG;R  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); cV&(L]k>`  
break; 7bQ#M )}  
} g3e\'B'  
} at6f(+  
else =WJ*$j(  
break; o Ep\po1  
} - Kj$A@~x  
} 7:mM`0g!  
catch(IOException e){e.printStackTrace ();} 8 x|NR?  
catch(Exception e){e.printStackTrace ();} frc>0\  
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,yAvLY5P  
Utility.log(nFileLength); M\e%GJ0  
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return nFileLength; 9)aXLM4Y  
} -t:yy:4  
6H.D`"cj  
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//保存下载信息（文件指针位置） 5W 5\*L  
private void write_nPos()
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{ DWm$:M4z  
try{ I&Yu=v/_  
output = new DataOutputStream(new FileOutputStream(tmpFile)); vRRi"bo  
output.writeInt(nStartPos.length); ]c[80F-  
for(int i=0;i<nStartPos.length;i++) !<((@*zU  
{ 1wE~dpnx  
// output.writeLong(nPos); !Lk|eGd*  
output.writeLong(fileSplitterFetch.nStartPos); gPQ2i])"Q  
output.writeLong(fileSplitterFetch.nEndPos); eu^z&R!um  
} oKA8)~Xqou  
output.close(); SZK~<@q5  
} @xSS`&b  
catch(IOException e){e.printStackTrace ();} 19bP0y  
catch(Exception e){e.printStackTrace ();} )Qp?N<&'  
} #*}4=  
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2+sNt6B2  
//读取保存的下载信息（文件指针位置） .QRQvtd.  
private void read_nPos() 5s;HF |2x  
{ Co[  r
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try{ =NH:/j^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); iNd8M V  
int nCount = input.readInt(); Tj<W4+p{  
nStartPos = new long[nCount]; |v[{k>7f  
nEndPos = new long[nCount]; ^3*/x%A,g  
for(int i=0;i<nStartPos.length;i++) + [|2k(U  
{ y5BNHweaRb  
nStartPos = input.readLong(); &AZr(>  
nEndPos = input.readLong(); :&&Ps4\Sq  
} 7MOjZD4?  
input.close(); bkLm]n3  
} 1i$9x$4~E  
catch(IOException e){e.printStackTrace ();} +>44'M^Z|(  
catch(Exception e){e.printStackTrace ();} v&xk?F?WU,  
} a}hpcr({?  
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2}b1PMpZG  
private void processErrorCode(int nErrorCode) 2\CFt;fk  
{ V78QV3  
System.err.println("Error Code : " + nErrorCode); ]wER&/v"  
} 1EyM,$On  
u"?cmg<.1  
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//停止文件下载 dfO@Yo-?*'  
public void siteStop() mxGa\{D#y  
{ %kKe"$)0  
bStop = true; kQsyvE  
for(int i=0;i<nStartPos.length;i++) ) e;)9~  
fileSplitterFetch.splitterStop(); FxTOc@<  
V[HHP_  
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} TStu)6%`  
} iVFHr<zk  
//负责部分文件的抓取 hGcOk[m 4  
**FileSplitterFetch.java O)Nj'Hcu  
*/ %a{cJ6P  
package NetFox; WG1UvPK  
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import java.io.*; y4C_G?  
import java.net.*; :@`Ll;G  
u/hFf3  
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public class FileSplitterFetch extends Thread { Q*^zphT  
/H:'(W_b;  
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String sURL; //File URL <fJoHS  
long nStartPos; //File Snippet Start Position ]O,!B''8k  
long nEndPos; //File Snippet End Position A%"mySW  
int nThreadID; //Thread's ID HZ>Xm6DnC5  
boolean bDownOver = false; //Downing is over dp&4G6Y<A  
boolean bStop = false; //Stop identical E;@`{ v  
FileAccessI fileAccessI = null; //File Access interface yCf*ts1  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (=j]fnH?  
{ q-KN{y/  
this.sURL = sURL; so9h6K{qcp  
this.nStartPos = nStart; S"!nM]2L  
this.nEndPos = nEnd; l=Jbuc  
nThreadID = id; |z<E%`u%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >Yl?i&3n  
} LrX7WI  
d?$FAy'o5  
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public void run() ((SN We  
{ 1Yo9Wf;vP  
while(nStartPos < nEndPos && !bStop) c]P`U(q9TV  
{ PB.@G,)  

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try{ ^
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URL url = new URL(sURL); ' &^:@V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); od"Oq?~/t  
httpConnection.setRequestProperty("User-Agent","NetFox"); K=;z&E=<c  
String sProperty = "bytes="+nStartPos+"-"; a-MDZT<xA+  
httpConnection.setRequestProperty("RANGE",sProperty); 5)wz`OS  
Utility.log(sProperty); w6F4o;<PR  
q=M!YWz  
1 xm8w$%  
InputStream input = httpConnection.getInputStream(); jQFAlO(E':  
//logResponseHead(httpConnection); +?),BRCce  
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byte[] b = new byte[1024]; ;[R{oW Nw  
int nRead; k
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) )(oRJu)y  
{ u}W R1u[  
nStartPos += fileAccessI.write(b,0,nRead); 4yV}4f$q  
//if(nThreadID == 1) : P>Wd3m  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QmT L-  
} qt=gz6!  
|2,u!{  
+?5nkhH  
Utility.log("Thread " + nThreadID + " is over!"); gI~Ru8  
bDownOver = true; J
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//nPos = fileAccessI.write (b,0,nRead); EJ;:O1,6H  
} 5`53lK.C  
catch(Exception e){e.printStackTrace ();} X-|Lg.s  
} /XEUJC4  
} h$)+$^YI  
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ne4j_!V{Mf  
//打印回应的头信息 2%y}El^+_  
public void logResponseHead(HttpURLConnection con) _5uzu6:y  
{ 56;lB$)"  
for(int i=1;;i++) *.#d'~+  
{ rK;F]ei  
String header=con.getHeaderFieldKey(i); -/*-e /+b  
if(header!=null) ]mYT!(}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); v)
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Utility.log(header+" : "+con.getHeaderField(header)); ZW{pO:-  
else ^a#Vp  
break; R#.FfWTZ  
} p}$VBl$'  
} BUqe~E|I  
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public void splitterStop() 5(R ./  
{ 1K.i>]}>  
bStop = true; N2[EdOJT_  
} w#_/CUL  
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]|ew!N$ar=  
} .Xnw@\k'  
}ac0}  
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/* 3e+ Ih2  
**FileAccess.java 48l!P(>?y  
*//文件访问(定位，写) Q>]FO  
package NetFox; G9J+D?'hH  
import java.io.*; Sz|;wsF{  
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!

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public class FileAccessI implements Serializable{ .Az'THD}  
wiKUs0|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 K;Qlg{v  
RandomAccessFile oSavedFile; {XAm3's  
long nPos; oh c/{D2  
@}k5rcQ*/  
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public FileAccessI() throws IOException ]f#1G$  
{ Loo48  
this("",0); c `C /U7j  
} >|Ps23J#  
BM9J/24  
<RH2G  
public FileAccessI(String sName,long nPos) throws IOException /qp)n">  
{ nA$zp  
oSavedFile = new RandomAccessFile(sName,"rw"); %2>ya>/M  
this.nPos = nPos; jI:5[. Y  
oSavedFile.seek(nPos); C\#E1\d  
} s|L}wtc  
_P9Th#UAg  
I*8i=O@0T  
public synchronized int write(byte[] b,int nStart,int nLen) 3~v'Ev  
{ Sxo9y0K8-  
int n = -1; 's#"~<L^e  
try{ y^pzqv  
oSavedFile.write(b,nStart,nLen); y qDE|DIez  
n = nLen; &!7{2E\7C  
} Kgh@.Ir  
catch(IOException e) zSt6q  
{ M{M>$p
t  
e.printStackTrace (); aF2vw{wT}  
} Tv2d?y  
&cy@Be}|T  
fy&vo~4i;  
return n; O%feBe  
} LA?h+)  
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} `j+[JMr  
/sHWJ?`&/,  
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/* !U,W; R  
**SiteInfoBean.java lQ/u#c$n  
*/ x`:zC#  
package NetFox; (prqo1e@  
:
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X@`kuWIUw  
public class SiteInfoBean { HAa$pGb  
]3UEju8$  
';<gc5EK  
private String sSiteURL; //Site's URL 1Q-O&\-xg  
private String sFilePath; //Saved File's Path =P>c1T1-  
private String sFileName; //Saved File's Name cbsU!8
 
private int nSplitter; //Count of Splited Downloading File |-kU]NJFR  
}AdA? :7A  
9[#9cv  
public SiteInfoBean() 3@xn<eu  
{//nSplitter的缺省值为5 nSUQ Eho<  
//default value of nSplitter is 5 5~ho1Ud  
this("","","",5);
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} 6R_G{AWLL  
dk}T&qZ~p  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gr]:u4}  
{ `rt?n|*
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sSiteURL= sURL; Hqsj5j2i  
sFilePath = sPath; <<a1a
 
sFileName = sName; rmVF88/;  
this.nSplitter = nSpiltter; ks{y=@<,  
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.7lDJ2  
} rDr3)*H?0  
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public String getSSiteURL() %=C49(/K_  
{ e6O+hC]:  
return sSiteURL; !yxb=>A  
} k;aV4 0N9  
++b1VBP  
f]N.$,:$  
public void setSSiteURL(String value) T_T@0`7  
{ !{hC99q6  
sSiteURL = value; <~wr;"S  
} 5!GL"  
fyb:eO}  
iIZDtZFF  
public String getSFilePath() bo>4:i  
{ `|9NxF+  
return sFilePath; ji'NR  
} $_bhZnYp7  
/da5"  
?f}lYQzM  
public void setSFilePath(String value) POZ5W)F(  
{ 7r,s+u.  
sFilePath = value; }r%
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} vR;?~^{*s  
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M  
55aJ=T  
public String getSFileName() ~96fyk
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{ 4.>rd6BAN-  
return sFileName; I.V?O}   
} k5s8s@  
?<_yW#x6  
K chp%  
public void setSFileName(String value) ?ykQ]r6a<  
{ wOfx7D  
sFileName = value; 6xDYEvHS  
} hT c VMc  
|s<IZ2z]}R  
soSdlV{  
public int getNSplitter() /iz{NulOz*  
{ /Mac:;W`  
return nSplitter; D/& 8[Z/Cn  
} iR_j h=2{  
x:Mh&dq?  
N*vBu`  
public void setNSplitter(int nCount) '{e9Vh<x  
{ pb>TUKvT&  
nSplitter = nCount; 6oh\#v3zV  
} r8
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} ihv=y\Jt  
ly!vbpE_  
]VuB2L[D  
/* O/Q7{5n  
**Utility.java !&8nwOG  
*/ Q~p)@[q  
package NetFox; 25:[VH$:4  
T4 :UJj}  
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public class Utility { tBJCfM  
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public Utility() yJyovfJz.  
{ @e`%'  
REEs}88);'  
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} T/m4jf2  
Z4&,KrV  
//线程睡眠 q?&Ap*  
public static void sleep(int nSecond) &oU) ,H  
{ B^;G3+}  
try{ "L?h
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Thread.sleep(nSecond); o7_*#5rD
 
} @ )bCh(u  
catch(Exception e) D90.z"N\i9  
{ {c(@u6l28  
e.printStackTrace (); xZMQ+OW2i  
} 5mtsN#  
} zCpsGr  
,sa%u Fm  
//日志 -[h2fqu1  
public static void log(String sMsg) YI877T9>  
{
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System.err.println(sMsg); Lo<-;;vQ  
} Fl{@B*3@w  
jV}tjwq  
*6C ]CS  
public static void log(int sMsg) E4CyW  
{ 4lVvs(W?  
System.err.println(sMsg); xE.yh#?.k  
} y}\d]*5  
} ApT
8;F B  
>ocDh~@aP  
4Go$OQ`  
/* Ml"i^LR+  
**TestMethod.java z_;:6*l=:  
*/ `rWT^E@p5m  
package NetFox; .eNeqC  
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tz6N,4J?  
public class TestMethod { tPQjjoh  
?o>JX.Nl&7  
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public TestMethod() s%6{X48vY^  
{ ///xx/weblogic60b2_win.exe L  `\>_  
try{ (=jztIZC
 
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \me'B {aa  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); EC:u;2f!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \dx$G?R
 
fileFetch.start(); jmE\+yz  
} [iO*t,3@h  
catch(Exception e){e.printStackTrace ();} I:l/U-b7h  
VZhHO d  
d~|/LR5  
} 8:9/RL\"x  
1ZrJ7a7=  
#M)SAe2  
public static void main(String[] args) $2
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{ ;YfKG8(0  
new TestMethod(); ?D\6@G:,#@  
} q{c/TRp7  
} }hm"49,O  
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