http断点续传简单实现（java)

/* rU |%  
**SiteFileFetch.java @s|G18@
 
*/ Y'+mC  
package NetFox; GboZ T68  
import java.io.*; [y&uc  
import java.net.*;  <dKHZ4  
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public class SiteFileFetch extends Thread { dAr=X4LE  
{ V$}qa{P  
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SiteInfoBean siteInfoBean = null; //文件信息Bean s>I~%+V.?:  
long[] nStartPos; //开始位置 J(Fk@{!F.*  
long[] nEndPos; //结束位置 FvXpqlp  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n#S?fsQN  
long nFileLength; //文件长度 :I2spBx  
boolean bFirst = true; //是否第一次取文件 )E*-  
boolean bStop = false; //停止标志 B.4Or]  
File tmpFile; //文件下载的临时信息 98Y1-Z^ .  
DataOutputStream output; //输出到文件的输出流 RDOV+2K  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） LYke\/ md  
public SiteFileFetch(SiteInfoBean bean) throws IOException +62}//_?  
{ (,R\6  
siteInfoBean = bean; c{3P|O&.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); U.Fs9F4M#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); F*JbTEOn  
if(tmpFile.exists ()) jGUegeq  
{ b=kY9!GN,v  
bFirst = false; L>n^Q:M  
read_nPos(); "#8I &xZK  
} zXW;W$7V4  
else Dn48?A[v  
{ ~IFafAO&  
nStartPos = new long[bean.getNSplitter()]; |)OC1=As  
nEndPos = new long[bean.getNSplitter()]; #!C|~=  
} 5^Ny6t  
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} Ie}7#>S  
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public void run() 7|k2~\@q  
{ K_fJ{Vc>O  
//获得文件长度 Flaqgi/j  
//分割文件 \rY\wa  
//实例FileSplitterFetch 2S//5@~_m  
//启动FileSplitterFetch线程 sWKv>bx  
//等待子线程返回 kbSl.V%)  
try{ n]8*yoge  
if(bFirst)
{S`Rr/E|%  
{ N}Or+:"O:q  
nFileLength = getFileSize(); NNBT.k3)  
if(nFileLength == -1) nK`H;k  
{ zp\_5[qJ;  
System.err.println("File Length is not known!"); Pf~0JNnc  
} *G[` T%g  
else if(nFileLength == -2) Mehp]5*  
{ *i"Mu00b  
System.err.println("File is not access!"); p\}!uS4 (  
} l-2lb&n  
else #!>`$  
{ & j*Ylj}  
for(int i=0;i<nStartPos.length;i++) {KSy I#  
{ 1ZXRH;J40  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); PHMp,z8  
} i "aQm  
for(int i=0;i<nEndPos.length-1;i++) @h\i<sh!^  
{ !Pu7%nV.  
nEndPos = nStartPos[i+1]; jX,A.  
} KVHK~Y-G  
nEndPos[nEndPos.length-1] = nFileLength; ]UrlFiR  
} a YY1*^  
} bd3>IWihp  
&zPM#Q  
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//启动子线程 z'zC  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !q8A!P4|'  
for(int i=0;i<nStartPos.length;i++) \5b<!Nl  
{ _+gpdQq\p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )+.AgqxI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Cyu
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nStartPos,nEndPos,i); akQb%Wq  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 5;[0Q  
fileSplitterFetch.start(); ?h8/\~Dw  
} z.W1Za  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vIFx'S~D  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); WX+@<y}%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", M+4S>Sjw  
nEndPos = " + nFileLength); U}{\qs-zt  
// fileSplitterFetch[nPos.length-1].start(); XlGB`P>?KD  
]xhH:kW4  
)' 2vUt`_7  
//等待子线程结束 |h:3BV_  
//int count = 0; 'v@1_HHW\  
//是否结束while循环 [{J1b  
boolean breakWhile = false; &jDRRT3  
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while(!bStop) * =O@D2g0  
{ gKb5W094@  
write_nPos(); s3M#ua#mX  
Utility.sleep(500); CzT_$v_  
breakWhile = true; Vb2")+*:  
*c@]c~hY,  
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for(int i=0;i<nStartPos.length;i++) S*rcXG6Q^  
{ YGLR%PYv"  
if(!fileSplitterFetch.bDownOver) F,XJGD*  
{ UOIZ8Po  
breakWhile = false; <7X+-%yb;  
break; *tT5Zt/&Sr  
} St1>J.k_  
} c{f1_qXN  
if(breakWhile) &l~=c2  
break; =`%%
*  
3*b!]^d:D  
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//count++; ~K|o@LK  
//if(count>4)
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// siteStop(); QLTE`t5w3'  
} g? \pH:|79  
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System.err.println("文件下载结束！"); _d<\@Tkw  
} #60<$HO:Z  
catch(Exception e){e.printStackTrace ();} 4>@-1nt}  
} KL*UU,qU  
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&nZ.$UK<  
//获得文件长度 j8p'B-yS  
public long getFileSize() ?r~](l   
{ ]9pcDZB  
int nFileLength = -1; k4nA+k<WI`  
try{ 
#kGxX@0  
URL url = new URL(siteInfoBean.getSSiteURL()); 8%9OB5?F6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |zL.PS  
httpConnection.setRequestProperty("User-Agent","NetFox"); Xq%!(YD|  
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int responseCode=httpConnection.getResponseCode(); /h%MWCZWm^  
if(responseCode>=400) :hxZ2O?5_  
{ @)8C
 
processErrorCode(responseCode); h-h}NCP  
return -2; //-2 represent access is error Jh:-<xy)  
} 3'2}F%!Mv  
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String sHeader; & ~[%N O  
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for(int i=1;;i++) g@"6QAP  
{ O^gq\X4}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); PZl(S}VY  
//Utility.log(in.readLine()); =
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sHeader=httpConnection.getHeaderFieldKey(i); ]QU52R@M  
if(sHeader!=null) Onoi6^G  
{  g^En6n)  
if(sHeader.equals("Content-Length")) i&FC-{|Z  
{ QX~*aqS3s8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ic&t_B*i}]  
break; XT_BiZ%l5O  
} ?8C+wW  
} M !OI :v  
else vR~*r6hX8  
break; 49Ue2=PP#  
} @kwD$%*0  
} #(*WxVE  
catch(IOException e){e.printStackTrace ();} 6YU2  !x  
catch(Exception e){e.printStackTrace ();} C5RDP~au  
uf)W?`e~  
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Utility.log(nFileLength); .^.UJo;4G  
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return nFileLength; cCV"(Oo[H|  
} {Q(6 .0R  
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.Na>BR\F  
//保存下载信息（文件指针位置） NV-9C$<n2!  
private void write_nPos() /9w}[y*E  
{ |H_)u  
try{ PewPl0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); X7c*T /  
output.writeInt(nStartPos.length); p go\(K0  
for(int i=0;i<nStartPos.length;i++) Z#MODf0H@  
{ q=1SP@;\6  
// output.writeLong(nPos); '/ &"  
output.writeLong(fileSplitterFetch.nStartPos); :M[E-j;  
output.writeLong(fileSplitterFetch.nEndPos); 4l`gAE$  
} \]ODpi 2  
output.close(); 2aje$w-  
} Z|?XQ-R5  
catch(IOException e){e.printStackTrace ();} V_W=MWs&+  
catch(Exception e){e.printStackTrace ();} ^:)&KV8D|  
} wbS++cF<  
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//读取保存的下载信息（文件指针位置） z:G9Uu3H(  
private void read_nPos() E0DEFB  
{ _gGy(`  
try{ ? sewU9*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L2h+[f  
int nCount = input.readInt(); 6~/H#8Kdn  
nStartPos = new long[nCount]; P*T)/A%4  
nEndPos = new long[nCount]; )eV40l$ M  
for(int i=0;i<nStartPos.length;i++) w9PY^U.Y3e  
{ ::`j@ ]  
nStartPos = input.readLong(); GQZUC\cB  
nEndPos = input.readLong(); J;kbY9e  
} j5)qF1W,  
input.close(); 7=AKQ7BB>b  
} vZDQ@\HrC  
catch(IOException e){e.printStackTrace ();} ,`7GI*Vq  
catch(Exception e){e.printStackTrace ();} 5
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} 5,((JxX$  
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L
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private void processErrorCode(int nErrorCode) j&mL]'Zy  
{ PYf`a`dH  
System.err.println("Error Code : " + nErrorCode); A{o{o++  
} v:0i5h&M  
]1[;A$7  
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//停止文件下载 VV4_  
public void siteStop() k1H0hDE  
{ C/Z"W@7#;  
bStop = true; TatyD**(  
for(int i=0;i<nStartPos.length;i++) yEny2q}  
fileSplitterFetch.splitterStop(); -&A[{m<,>  
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} h5gXYmk  
} 9$S,P|  
//负责部分文件的抓取 u~kwNN9t3  
**FileSplitterFetch.java p{J_d,JH  
*/ K]oPh:E  
package NetFox; ] 6gu  
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v8IL[g6"  
import java.io.*; Z9D4;1  
import java.net.*; vSA%A47G  
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/fq6-;co+  
public class FileSplitterFetch extends Thread { PS22$_}  
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String sURL; //File URL ~e+w@ lK  
long nStartPos; //File Snippet Start Position gsp7N  
long nEndPos; //File Snippet End Position K
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int nThreadID; //Thread's ID "/fs%F  
boolean bDownOver = false; //Downing is over h;KK6*Z*$E  
boolean bStop = false; //Stop identical S\ZAcz4  
FileAccessI fileAccessI = null; //File Access interface C5MqwNX  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?<6@^X"  
{ #Z0-8<\  
this.sURL = sURL; (kY@7)d'e  
this.nStartPos = nStart; 9DPb|+O-  
this.nEndPos = nEnd; %N1"*</q  
nThreadID = id; djGs~H>;U_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 cWM:  
} 5NFRPGYX  
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public void run() tgB=vIw?3  
{ +99Bi2H}o  
while(nStartPos < nEndPos && !bStop) P7UJ-2%Y+  
{ cJ/4Gl  
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try{ wASX\D }  
URL url = new URL(sURL); ="2/\*.SL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _r5wF(Y?7  
httpConnection.setRequestProperty("User-Agent","NetFox"); - wWRm  
String sProperty = "bytes="+nStartPos+"-"; U(Z!J6{c  
httpConnection.setRequestProperty("RANGE",sProperty); I=odMw7Hj  
Utility.log(sProperty); TzY*;  
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InputStream input = httpConnection.getInputStream(); dN0mYlu1|  
//logResponseHead(httpConnection); & g$rrpTzv  
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byte[] b = new byte[1024]; AIv<f9*.:  
int nRead; *m&%vj.Kc  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }Aw47;5q;  
{ ^Et,TF\  
nStartPos += fileAccessI.write(b,0,nRead); u GAh7Sop  
//if(nThreadID == 1) A_i zSzC1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .R\p[rv&  
} FJF3B)Va|  
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Utility.log("Thread " + nThreadID + " is over!"); :~erh}~ps  
bDownOver = true; `yYvYc
 
//nPos = fileAccessI.write (b,0,nRead); zb?kpd}r  
} Z)5klg$c  
catch(Exception e){e.printStackTrace ();} >3!DOv   
} q}sK  
} qw2)v*Fn  
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//打印回应的头信息 6i-*N[!U  
public void logResponseHead(HttpURLConnection con) )WmZP3$^TX  
{ 1\IZcJ {  
for(int i=1;;i++) t2U$m'(A&  
{ vbedk+dd?A  
String header=con.getHeaderFieldKey(i); m#;.yR  
if(header!=null) kU1 %f o  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 7JS#a=D#  
Utility.log(header+" : "+con.getHeaderField(header)); &urb!tQ>&  
else gW}}5Xq  
break; eVrNYa1>H  
} (rIXbekgB  
} JSRg?p\  
v4D!7t&v"  
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public void splitterStop() \6i9q=  
{ jceHKl  
bStop = true; L\YZT| K(  
} 8:<1|]]  
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} c[Yq5Bu{y  
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/* cmae&Atotw  
**FileAccess.java v >NTh  
*//文件访问(定位，写) sY_fq
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package NetFox; Xz" JY
 
import java.io.*; bu;vpNa  
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public class FileAccessI implements Serializable{ *x5o=)Y  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %bN"bxv^  
RandomAccessFile oSavedFile; JLt{f=`%F  
long nPos; L-SdQTx_  
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public FileAccessI() throws IOException aL{EkiR  
{ 5t TLMZ`o  
this("",0); j_hjCQ  
} 2
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public FileAccessI(String sName,long nPos) throws IOException (]oFB$  
{ YK7
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oSavedFile = new RandomAccessFile(sName,"rw"); Ed4_<:  
this.nPos = nPos; 5QNBB|X@  
oSavedFile.seek(nPos); =xl7vHn7  
} ?NQD#  
6CCZda@  
+HYN$>  
public synchronized int write(byte[] b,int nStart,int nLen) N <ja6Ac  
{ Id; mn}+~  
int n = -1; Q^\{Zg)p  
try{ ;H`=):U  
oSavedFile.write(b,nStart,nLen); Ti /;|lP@  
n = nLen; ,80jMs  
} Z(#XFXd  
catch(IOException e) 34HFrMi  
{ X}kVBT1w+x  
e.printStackTrace (); ^a: Saq-}  
} ikeJDKSG  
@?(nwj~ s`  
+ ?[ ACZF  
return n; QJb7U5:B+  
} `1}HWLBX.  
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} 8.6no  
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/* Q3'(f9 x  
**SiteInfoBean.java ] `b<"  
*/ [J(@$Qix  
package NetFox; o%y+Y;|?J  

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public class SiteInfoBean { d{vc wZQ  
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;))[P_$zB  
private String sSiteURL; //Site's URL :T8u?@.  
private String sFilePath; //Saved File's Path qen44;\L  
private String sFileName; //Saved File's Name WMt&8W5  
private int nSplitter; //Count of Splited Downloading File ~7FEY0/  
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public SiteInfoBean() zzDNWPzsA  
{//nSplitter的缺省值为5 e)fJd*P  
//default value of nSplitter is 5 HPv&vdr3  
this("","","",5); %`t]FV^#  
} *rujdQ
f  
$_%2D3-;D  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )of5229  
{ &z{dr~  
sSiteURL= sURL; *RUd!]bh  
sFilePath = sPath; VuYWb)@  
sFileName = sName; ^H@!)+ =  
this.nSplitter = nSpiltter; oi%5t)VsS  
a,F8+ Pb>  
81%qM7v9H  
} WHdqO8  
j};pv2  
,4h!"c  
public String getSSiteURL() 8VBkIYgb  
{ v)v{QNQp^  
return sSiteURL; a!S
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} KBUAdpU8  
QBN=l\m+  
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public void setSSiteURL(String value)  h;:Se  
{ g(z#h$@S  
sSiteURL = value; Q}k_#w  
} 7k[`]:*o  
=]2RC1#}e  
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public String getSFilePath() ~0Q\Lp);  
{ @5dBb+0J  
return sFilePath; &D&5UdN x  
} PG-cu$\??  
VygXhh^7\  
c DEe?WS  
public void setSFilePath(String value) ~I8"l@H>  
{ q^T&A[hMPx  
sFilePath = value; ID{Pzmt-  
} 8O;rp(N.n  
}SJLBy0  
sbq44L)  
public String getSFileName() H8=vQy  
{ /(WX!EEsB  
return sFileName; }AeE|RNc  
} Npg5Z%+y  
0N} wD-  
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public void setSFileName(String value) }y-AoG  
{ XyKKD&j  
sFileName = value; s1*WK&@  
} D; 35@gtj  
\e5,`  
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public int getNSplitter() (0+GLI8  
{ OA8b_k~  
return nSplitter;
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} u0 'pR# m|  
.-1{,o/
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public void setNSplitter(int nCount) (fLbg,  
{ =>9.@`.  
nSplitter = nCount; NiJ?no  
} gC,0+Y~  
} _,-M8=dL%*  
-$!Pf$l@  
Kw5+4R(5  
/* _`Yvfz3  
**Utility.java _QtQPK\+  
*/ (w7cdqe  
package NetFox; W
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uvK%d\d  
O.40^u~
 
public class Utility { vng8{Mx90*  
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5F_:[H =   
public Utility() gCBZA;/  
{ m#}{"d&J  
v.8S V
]  
;hJ/t/7  
} 4>ce,*B1  
~4 xBa:*z  
//线程睡眠 ~Sem_U`G  
public static void sleep(int nSecond) %cjGeS6}  
{ BKlc{=
 
try{
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Thread.sleep(nSecond); <?va) ou  
} =rtA{g$)+  
catch(Exception e) Q9'p3"yoE  
{ 3b/vyZF  
e.printStackTrace (); #di_V"  
} RlPByG5K  
} lL+^n~g  
W2LblZE!  
//日志 25@j2K(  
public static void log(String sMsg) _w,0wn9N$  
{ )aA9z(x  
System.err.println(sMsg); JGNxJ S<]  
} 59J$SE  
:H8L(BsI  
CH+&  
public static void log(int sMsg) .t%Vx  
{ R3!vS+5rR  
System.err.println(sMsg); HnY"6gTNK  
} "}aM*(l+\  
} z7pXpy \  
KcF+!;:  
Y_YIJ@  
/* YqCK#zT/  
**TestMethod.java 6zZR:ej  
*/ ]@}BdMlHp  
package NetFox; q;~>h  
]c=1-Rl
  
i1Sc/  
public class TestMethod { AFUl  
_%%"Y}  
myX0<j3G5  
public TestMethod() >^HTghgRD  
{ ///xx/weblogic60b2_win.exe w:+#,,rwzV  
try{ X[Gk!dr#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); QNwAuH T  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zFQkUgb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); fzG1<Gem  
fileFetch.start(); ]H7Mx\  
} /\I%)B47^9  
catch(Exception e){e.printStackTrace ();} <5vB{)Tq  
;!sGfrs0$  
r@UY$z  
} 0! %}  
80>!qG  
{S(T1ua  
public static void main(String[] args) $s!meg@s  
{ uL AXN  
new TestMethod(); " CoR?[,x  
} jn Y3G  
} ]}y'3aW  
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