http断点续传简单实现（java)

/* mIu-  
**SiteFileFetch.java @R+bR<}]  
*/ ;DWtCtD  
package NetFox; Yv0;UKd  
import java.io.*; qkX}pQkG)h  
import java.net.*; DtBIDU]  
}q0lbwYlb  
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public class SiteFileFetch extends Thread { ejY|o Bj  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Al?LO;$Pa?  
long[] nStartPos; //开始位置 { bjK(|  
long[] nEndPos; //结束位置 C:C9swik"5  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @)0-oa,u+  
long nFileLength; //文件长度 q7id?F}3&  
boolean bFirst = true; //是否第一次取文件 I{Pny/d`  
boolean bStop = false; //停止标志 /rRQ*m_  
File tmpFile; //文件下载的临时信息 b}P5*}$:9"  
DataOutputStream output; //输出到文件的输出流 cp|&&q  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \VW&z:/*pZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException .:eNL]2%:  
{ ]V9z)uz  
siteInfoBean = bean; gemjLuf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RfPRCIo  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); I"*;fdm  
if(tmpFile.exists ()) }@Mx@ S  
{ (`0dO8  
bFirst = false; @d5G\1(%  
read_nPos(); z?~W]PWiZ  
} i*16kdI.  
else
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{ =6#tJgg8  
nStartPos = new long[bean.getNSplitter()]; 2Z]<MiAxD  
nEndPos = new long[bean.getNSplitter()]; !oXA^7Th6]  
} #UN(R  
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} r30t`o12i  
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public void run() j[
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{ m.~&n!1W*`  
//获得文件长度 $mA+4ISK  
//分割文件 <,~ =o  
//实例FileSplitterFetch iR-MuDM  
//启动FileSplitterFetch线程 13s0uyYU<m  
//等待子线程返回 YM9oVF-  
try{ Q !5P  
if(bFirst) ],r?]>  
{ f[)_=T+  
nFileLength = getFileSize(); s)]Z*#ZZ  
if(nFileLength == -1) M,[u}Rf^w  
{ (]BZ8GOx  
System.err.println("File Length is not known!"); <@CBc:j0  
} UV>^[/^O  
else if(nFileLength == -2) #&\hgsw/T  
{ tK&.0)*=  
System.err.println("File is not access!"); )2X ng_,  
} X-di^%<  
else ZyqTtA!A  
{ JL1%XQ i  
for(int i=0;i<nStartPos.length;i++) 
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{ rVkoj;[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); J.x>*3<l  
} D5X;hd  
for(int i=0;i<nEndPos.length-1;i++) 5*1wQlL  
{ 1r}fnT<  
nEndPos = nStartPos[i+1]; =+gp~RR,  
} NF=FbvNe  
nEndPos[nEndPos.length-1] = nFileLength; /p') u3  
} @]f"X>  
} l79jd%/m  
q>&F%;q1]  
?r@euZ&  
//启动子线程 ypXKw7f(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )>,b>7  
for(int i=0;i<nStartPos.length;i++) 4ei .-  
{ F2yM2Ldx  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >Uvtsj#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ,eRl Z3T  
nStartPos,nEndPos,i); Yt*M|0bL  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RIX0AE  
fileSplitterFetch.start(); iUh_rX9A"  
} Ms?V1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RVfRGc^lK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); S[UHx}.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {Ny\9r  
nEndPos = " + nFileLength); &)Z8Qu  
// fileSplitterFetch[nPos.length-1].start(); 1Qf21oN{  
(H9%a-3  
( DwIAO/S  
//等待子线程结束
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//int count = 0; bIizh8d?  
//是否结束while循环 > 3JU  
boolean breakWhile = false; @u/<^j3Q  
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XzQ=8r>l  
while(!bStop) @.kv",[{[  
{ 8aGZ% UI  
write_nPos(); MAR kTxzi  
Utility.sleep(500); l1c&a[M)  
breakWhile = true; ,$3  

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for(int i=0;i<nStartPos.length;i++) [p@NzS/  
{ i`r,B`V`08  
if(!fileSplitterFetch.bDownOver) ZP?k|sEH  
{ 6f=/vRAh$  
breakWhile = false; `.%;|"xR  
break; ~PvW+UMLk  
} FStE/2?  
} ?OKm~ Ek  
if(breakWhile) *6*#"#D  
break; cFUYT$8>  
d^ !3bv*h  
H'I|tPs  
//count++; CV4V_G  
//if(count>4) U^Z[6u  
// siteStop(); 3HbHl?-UNU  
} Xkl^!,  
4PiNQ'*  
XoSjYG(>,  
System.err.println("文件下载结束！"); p"H8;fPA0  
} r_xo>y~S  
catch(Exception e){e.printStackTrace ();} fY=iQ?{/[  
} &X+V}
 
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EhB9M!Y`@  
//获得文件长度 QY+#Vp<`  
public long getFileSize() #2ZXYH}  
{ &t%CuU]/@  
int nFileLength = -1; B<1*p,z  
try{ `1EBnL_1  
URL url = new URL(siteInfoBean.getSSiteURL()); 1`O`!plD+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); CX':nai  
httpConnection.setRequestProperty("User-Agent","NetFox"); j)-D.bY0  
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4Bx1L+Cg  
int responseCode=httpConnection.getResponseCode(); Z(K[oUJx  
if(responseCode>=400) NH'RU`U)  
{ +7 F7Kh  
processErrorCode(responseCode); H.idL6*G  
return -2; //-2 represent access is error P+}qaup  
} q'(WIv@  
(dMFYL>YP  
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m  
String sHeader; #]lUJ &M}e  
&K>]!yn   
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for(int i=1;;i++) 1AE/ILGo  
{ 7v,>sX  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); F5 LQgK-z  
//Utility.log(in.readLine()); i
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sHeader=httpConnection.getHeaderFieldKey(i); +crAkb}i  
if(sHeader!=null) `zzX2R Je  
{ K+v 250J$-  
if(sHeader.equals("Content-Length")) x(]s#D!)  
{ ~;eWQwD  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); iLmU|jdE  
break; ,Qyz2- w  
} Km,tfM5j  
} izFu&syv)  
else T@yH.4D  
break; tB_V%qH  
} :m&`bq  
} ~7 `x9MUc  
catch(IOException e){e.printStackTrace ();} m6;Xo}^w  
catch(Exception e){e.printStackTrace ();} ~|uCZ.;o  
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# Jdip)  
Utility.log(nFileLength); 5?O/Aub  
.qK=lHxT  
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return nFileLength; k5/nAaiVE  
} %+I(S
`}  
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w:
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//保存下载信息（文件指针位置） Ep?a>\  
private void write_nPos() "~V}MPt  
{ B4|`Z'U#;  
try{ HO@T2t[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); V)@MM2,  
output.writeInt(nStartPos.length); QK?5)[ J  
for(int i=0;i<nStartPos.length;i++) B8_l+dXO  
{ ;~1r{kXxA"  
// output.writeLong(nPos); WHNb.>  
output.writeLong(fileSplitterFetch.nStartPos); .vW~(ZuD  
output.writeLong(fileSplitterFetch.nEndPos); 4|2$b:t  
} VBH[aIW  
output.close(); `%ENGB|  
} O"#`i{^?2  
catch(IOException e){e.printStackTrace ();} %<M<'jxSca  
catch(Exception e){e.printStackTrace ();} u^]yz&9V  
} p +T&9  
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//读取保存的下载信息（文件指针位置） -:~`g*3#  
private void read_nPos() `PW=_f={  
{ he+[  
try{ 9Np0<e3p  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |wLQ)y*  
int nCount = input.readInt(); ##s!-.T  
nStartPos = new long[nCount]; 6sZRR{'  
nEndPos = new long[nCount]; xc/|#TC8?  
for(int i=0;i<nStartPos.length;i++) <
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{ l?R_wu,Q  
nStartPos = input.readLong(); 0l:5hD,)F  
nEndPos = input.readLong(); eXOFAd]>u  
} (C3d<a\:  
input.close(); (Dl"s`UH~  
} bv+e'$U3  
catch(IOException e){e.printStackTrace ();} * QR7t:([  
catch(Exception e){e.printStackTrace ();} ^LNc  
} >|'6J!Op  
XBY"7}  
h7y*2:l6  
private void processErrorCode(int nErrorCode) YSwD#jO0  
{ =#^dG''*"  
System.err.println("Error Code : " + nErrorCode); 0sUc6_>e  
} 0iL8i#y*  
FRg6-G/S  
)F$Stg3e  
//停止文件下载 41zeN++  
public void siteStop() .lFSFJ??  
{ 7 %|>7  
bStop = true; s{,e^T  
for(int i=0;i<nStartPos.length;i++) /,>.${,;u  
fileSplitterFetch.splitterStop(); X<QE]RZ  
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} 8;'n.SC{  
} eLTNnz  
//负责部分文件的抓取 {+[gf:Ev  
**FileSplitterFetch.java  qN QsU  
*/ {Psj#.qP1  
package NetFox; \'EWur"  
!K 9(OX2;  
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import java.io.*; kC k-  
import java.net.*; Y{yr-E #~M  
2G-? P"4l@  
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public class FileSplitterFetch extends Thread { Sy'>JHx  
dJ!o/y6  
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String sURL; //File URL 3?XLHMxW  
long nStartPos; //File Snippet Start Position e||_j  
long nEndPos; //File Snippet End Position %OtW\T=u  
int nThreadID; //Thread's ID ]03ZrZ! PM  
boolean bDownOver = false; //Downing is over cR&xl^BJ  
boolean bStop = false; //Stop identical KwHOV
$lD;  
FileAccessI fileAccessI = null; //File Access interface $G_<YVXcG  

:acQK=fe  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException a82mC r  
{ q"Md)?5N  
this.sURL = sURL; #Kl2K4  
this.nStartPos = nStart; +o3g]0  
this.nEndPos = nEnd;
8bGq"!w-  
nThreadID = id; 8<kme"%s  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #~+#72+x7  
} asi1c y\  
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public void run() PsgzDhRv  
{ m?j!0>  
while(nStartPos < nEndPos && !bStop) 9C$!tz>>+i  
{ j VZi_de  
)|{{}w~`  
.+Ej%|l%  
try{ -^b^6=#  
URL url = new URL(sURL); E5(Y*m!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %p9bl ,x  
httpConnection.setRequestProperty("User-Agent","NetFox"); c6HU'%v  
String sProperty = "bytes="+nStartPos+"-"; zK 2wLX  
httpConnection.setRequestProperty("RANGE",sProperty); UW*aSZ/?  
Utility.log(sProperty); O0~d6Ba  
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sb @hGS  
InputStream input = httpConnection.getInputStream(); lnDDFsA  
//logResponseHead(httpConnection); s=TjM?)
 
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byte[] b = new byte[1024]; xu=B  
int nRead; _@N)]!\MgP  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) dM UDLr-  
{ ?iX=2-  
nStartPos += fileAccessI.write(b,0,nRead); /;rN/ot2o  
//if(nThreadID == 1) \V>%yl{8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2eU[*x  
} AD\<}/3U  
L:M9|/  
.A\\v6@  
Utility.log("Thread " + nThreadID + " is over!"); xp&!Cl>C3\  
bDownOver = true; S=}~I  
//nPos = fileAccessI.write (b,0,nRead); 9oP{Al  
} *d@Hnu"q  
catch(Exception e){e.printStackTrace ();} x+cF1N2.  
} H/k W :k  
} n@;x!c< +  
$3'+V_CZ3  
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//打印回应的头信息 ~ ZL`E  
public void logResponseHead(HttpURLConnection con) Fnpn_O XlH  
{ t^,Qy.L0  
for(int i=1;;i++) 358/t/4{p  
{ Pm^N0L9?q  
String header=con.getHeaderFieldKey(i); @;fE%N  
if(header!=null) ~5NGDT#L*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;a&:r7]=  
Utility.log(header+" : "+con.getHeaderField(header)); oKi1=d+T  
else el?V2v[  
break; }+4Bf+u:  
} &a_kJ)J  
} qb4;l\SfT  
Jyci}CU3\Q  
7V{"!V5  
public void splitterStop() 66<\i ltUQ  
{ LU,"i^
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bStop = true; -FN6sNvIh  
} [ 5W#1 &  
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em[F|  
} "O[76}I+.q  
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/* g&3#22z  
**FileAccess.java uq4sbkP  
*//文件访问(定位，写) SrtVoe[  
package NetFox; qW~R-g]  
import java.io.*; cIvYfgIo9  
e=l5j"gq  
B21AcE  
public class FileAccessI implements Serializable{ ;3|Lw<D5;  
SP*JleQN  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 'ZH<g8:=@  
RandomAccessFile oSavedFile; iM|"H..  
long nPos; =)- Q?1q  
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public FileAccessI() throws IOException As~p1%nok  
{ P5}[*k%DQw  
this("",0); < }wAP_
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} n [Xzo}  
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public FileAccessI(String sName,long nPos) throws IOException zQ5jx5B":  
{ O;0<^M/0G  
oSavedFile = new RandomAccessFile(sName,"rw"); H='9zqYZ<W  
this.nPos = nPos; GHJ=-9{YL  
oSavedFile.seek(nPos); GoSWH2N  
} L%K_.!d^  
bepYe
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3{4/7DcX  
public synchronized int write(byte[] b,int nStart,int nLen) Sq|1f?_gU  
{ =x0"6gTz>  
int n = -1; !@Sf>DM"  
try{ r\n h.}s  
oSavedFile.write(b,nStart,nLen); BgWz<k}5M  
n = nLen; e#6&uFce  
} 5uV"g5?w  
catch(IOException e) vvsNWA
 
{ 6G<Hi"I  
e.printStackTrace (); Cre0e$ a  
} mU+FQX  
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8<-oJs_o+  
return n; ;2Ad])  
} ju^"vw  
5Vqmv<F;$Z  
*[xNp[
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} ;WS7.  
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(: TGev  
/* UiK+c30FU  
**SiteInfoBean.java *lerPY3 q  
*/ ^[seK)S=  
package NetFox; 2Ph7qEBQ22  
a4jnu:e  
KBr5bcm4u  
public class SiteInfoBean { Wt+y-ES  
cUZ!;*  
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private String sSiteURL; //Site's URL 7c
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private String sFilePath; //Saved File's Path E7yf[/it  
private String sFileName; //Saved File's Name N^Hn9n  
private int nSplitter; //Count of Splited Downloading File B)*#g  
}&(E#*>x  
h#@4@x{  
public SiteInfoBean() \Qi#'c$5+a  
{//nSplitter的缺省值为5 [t  
//default value of nSplitter is 5 |.8d,!5w}  
this("","","",5); kg?T$}O  
} 11B{gUv.]  
Y-%l7GErhL  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y/@;c)1b9  
{ sw$R2K{y  
sSiteURL= sURL; !k:zLjtp  
sFilePath = sPath; @vdc)vN[/  
sFileName = sName;  UL)"  
this.nSplitter = nSpiltter; :^H9W^2  
V<HOSB7  
tIxhSI^  
} ~"JE![XR  
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?v"K1C1.  
public String getSSiteURL() +(z_"[l"  
{ [>$\s=` h  
return sSiteURL; . QQ?w  
} zL)1^[%O9  
lTV@b&  
o5=)~D{/G3  
public void setSSiteURL(String value) NoJnchiU  
{ &h7smZO5
j  
sSiteURL = value; _@#uIOcE  
} _OJ0 < {E  
'<?v:pb9  
]^
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public String getSFilePath() QH7V_#6bKP  
{ Jb3>vCIn  
return sFilePath;  ko=aa5c  
} vz;7} Zj]  
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tA! M  
public void setSFilePath(String value) 79{.O`v  
{ MPKpS3VS  
sFilePath = value; ~j/bCMEf!  
} 1N!Oslum  
4;BW  
@4/~~  
public String getSFileName() zj~nnfoys  
{ i
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return sFileName; VM-qVd-  
} _=|nOj39  
_l24Ba$F6  
}g>dn  
public void setSFileName(String value) HF&h  
{ KjFZ  
sFileName = value; ig{A[7qN  
} iUeV5c
B  
qs6Nb'JvQR  
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public int getNSplitter() MB
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{ ~/j$TT"  
return nSplitter; 4ss&'h  
} &Pu+(~'Q  
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5nMkd/  
public void setNSplitter(int nCount) h^o+E2<]  
{
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nSplitter = nCount;
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} BW'L.*2  
} wXr>p)mP  
aL8p"iSG9  
zyaW3th  
/* c=b+g+*xd  
**Utility.java "bD+/\ z  
*/ 'ox0o:  
package NetFox; RDUT3H6~  
OD  
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public class Utility { \ V[;t-  
t2=a(N-/,  
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public Utility() a$C2}  
{ Ho|o,XvLv  
hMNJ'i}  
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} w
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=LlLE<X"%x  
//线程睡眠 Sp 7u_Pq{  
public static void sleep(int nSecond) c:=7lI  
{ `%$8cZ-kr  
try{ _REqT  
Thread.sleep(nSecond); `+roQX.p  
} C1h#x'k  
catch(Exception e) y\^@p=e  
{ O{PW  
e.printStackTrace (); nAIH`L"X  
} @)o0GHNP  
} rpUy$qrRc  
mbF(tSy  
//日志 rei 8LW  
public static void log(String sMsg) dX_!0E[c  
{ Wt>J`  
System.err.println(sMsg); x|.v{tQa  
} mfZ)^X  
]kRI}
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j*tk(o}qG  
public static void log(int sMsg) bsB},pc  
{ fZ[kh{|  
System.err.println(sMsg); p`d XqW  
} 2Oyy`k  
} @'*eC}\E  
'z)hG#{I  
LyGUvi  
/* 8QT<M]N%  
**TestMethod.java E[S? b=^  
*/ gXLCRn!iR  
package NetFox; 3I|O^   
\,2gTi,=  
w"{bp  
public class TestMethod { X` ATH^S  
uaiz*Im  
<x0)7xX  
public TestMethod() tE[H8  
{ ///xx/weblogic60b2_win.exe 4avc=Y5  
try{ :-)GNf yGz  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); uM<|@`&b  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); jk )Vb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3S5^`Ag#  
fileFetch.start(); ZI,j?i6\  
} y`4{!CEyLW  
catch(Exception e){e.printStackTrace ();} Z(p*Z,?u  
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jO=*:{#x  
} wtSvJI~o)  
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69Nw/$  
public static void main(String[] args) 80|onP
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{ <|a=hHPi:  
new TestMethod(); \^
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}
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} s D_G)c  
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