http断点续传简单实现（java)

/* 5J2p^$s  
**SiteFileFetch.java _2n/vF;I+_  
*/ cZK?kz_Y  
package NetFox; n,'AFb4AF  
import java.io.*; ="TOa"Zk  
import java.net.*; "BNmpP  
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public class SiteFileFetch extends Thread { *CD=cmdD*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean o!dkS/u-m  
long[] nStartPos; //开始位置 = Ow&UI  
long[] nEndPos; //结束位置 DmpJzHj|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]8cX#N,M  
long nFileLength; //文件长度 g$+O<a@n  
boolean bFirst = true; //是否第一次取文件 `DY4d$!4  
boolean bStop = false; //停止标志 3&d+U)E  
File tmpFile; //文件下载的临时信息 KNyD}1  
DataOutputStream output; //输出到文件的输出流 8o5^H>  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） J0)WRn"h  
public SiteFileFetch(SiteInfoBean bean) throws IOException S gsR;)2  
{ K<9MK>T  
siteInfoBean = bean; %_LHD|<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J#;m)5[ a%  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); <6@NgSFz'  
if(tmpFile.exists ()) Oua/NF)  
{ jM@I"JZb  
bFirst = false; V1V4
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read_nPos(); w [x+2  
} rca"q[,  
else !Yi<h/:  
{ Iur} ZA
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nStartPos = new long[bean.getNSplitter()]; v%e"4:K}?  
nEndPos = new long[bean.getNSplitter()]; 8@#Y <{  
} 8[p6C Jl)  
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} b#'a4j-u  
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public void run() ^/YAokj  
{ 6Z}))*3 9  
//获得文件长度 QlXF:Gx"=  
//分割文件 ]b$,.t5  
//实例FileSplitterFetch .Bn2;
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//启动FileSplitterFetch线程 i-W2!;G  
//等待子线程返回 $1 \!Oe[i  
try{ 'bO? =+c  
if(bFirst) 8LKZ3Y|  
{ lLf01sa4  
nFileLength = getFileSize(); @Oay$gP{T  
if(nFileLength == -1) C&"2`ll  
{ ~ ?_Z!eS  
System.err.println("File Length is not known!"); t$5]1dY$X
 
} U,(+rMeY0  
else if(nFileLength == -2) Z'kYf  
{ bW3o%
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System.err.println("File is not access!"); wZb@VG}%  
} ~ZC=!|Q#  
else N4N
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{ k&;L(D  
for(int i=0;i<nStartPos.length;i++) xfSvvCy  
{ gJv^v`X  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )ciHY6  
} Oz7v hOU  
for(int i=0;i<nEndPos.length-1;i++) 1 niTkop  
{ #-,`4x$m|  
nEndPos = nStartPos[i+1]; $B/cj^3  
} e28#Yh@U  
nEndPos[nEndPos.length-1] = nFileLength; uV:;y}T^Z  
} p7tC~]r:L  
} D:,<9%A  
$ wB  
6&T1 ZY`  
//启动子线程 #XPU$=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; m"}G-#  
for(int i=0;i<nStartPos.length;i++) C5 !n{  
{ [: j_Y3-9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /_(Dq8^g@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), '>$A7  
nStartPos,nEndPos,i); V>SA3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); tB7aHZ|  
fileSplitterFetch.start(); [J3;U6  
} Br??Gdd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SQk!o{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); "YZ`g}sG  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", d(XWt;KK  
nEndPos = " + nFileLength); 96j2D8=w  
// fileSplitterFetch[nPos.length-1].start(); ,#haai(  
wH<*  
1vb0G;a;|  
//等待子线程结束 lEs/_f3;A  
//int count = 0; 3!x)LUWfWY  
//是否结束while循环 9-SXu lgu  
boolean breakWhile = false; &YMj\KmlSg  
(*]Y<ve  
hn.fX:}  
while(!bStop) mqw.v$>  
{ ~3 (>_r  
write_nPos(); ha5\T'  
Utility.sleep(500); 5. i;IOx  
breakWhile = true; bcNYoZ8`  
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for(int i=0;i<nStartPos.length;i++) z{x -Vfd  
{ EK^2 2vi$  
if(!fileSplitterFetch.bDownOver) us+adS.l&  
{ Hua8/:![+  
breakWhile = false; %Et]w  
break; -:q7"s-}b  
} i/Z5/(
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} *UC^&5:  
if(breakWhile) @ XMC$s  
break; <^paRKEa+#  
{HeMdGn9  
3u<2~!sR  
//count++; cs)hq4-L`  
//if(count>4) ImVe71mh  
// siteStop(); &s5*akG  
} /_8V+@im  
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^ z;pP  
System.err.println("文件下载结束！"); .v{ty  
} u9Ro=#xt  
catch(Exception e){e.printStackTrace ();} mx2 Jt1  
} RB2u1]l  
e{=$4F  
T5)?6i-N  
//获得文件长度 dWA7U6c<  
public long getFileSize() AXFVsZH"zi  
{ 0OXd*  
int nFileLength = -1; :&MiO3#+  
try{ 04:Dbt~=?p  
URL url = new URL(siteInfoBean.getSSiteURL()); B!0[LlF+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y\x<!_&D  
httpConnection.setRequestProperty("User-Agent","NetFox"); Cpl)byb  
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int responseCode=httpConnection.getResponseCode(); ~7v^7;tT  
if(responseCode>=400) whshjl?a  
{ 2
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processErrorCode(responseCode); Rk<:m+V=  
return -2; //-2 represent access is error (_2eiE71  
} l:+1j{ d7  

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String sHeader; I g`#U~  
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for(int i=1;;i++) f 36rU  
{ dO2cgY}  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); O7W}Z1G  
//Utility.log(in.readLine()); RN0Rk 8AC  
sHeader=httpConnection.getHeaderFieldKey(i); ?d 4_'y   
if(sHeader!=null) YA jk'  
{ PNq#o%q  
if(sHeader.equals("Content-Length"))  f!<mI8H  
{ Kmtr.]Nj  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ts ] +W!:  
break; n
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} BLRrHaX0  
} !**q20-aP  
else t
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break; R)v`ZF,/b  
} 8cHZBM7'  
} iZUBw  
catch(IOException e){e.printStackTrace ();} Y:wds=lA  
catch(Exception e){e.printStackTrace ();} a[/p(O  
pw,.*N3P  
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Utility.log(nFileLength); <]<50  
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return nFileLength; xnArYm  
} /cg!Ap5  
/Wa+mp  
V
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//保存下载信息（文件指针位置） >v(Xc/oI
 
private void write_nPos() ^0 t`EZ$  
{ m$kmoY/  
try{ x?k6ek  
output = new DataOutputStream(new FileOutputStream(tmpFile)); q+ .=f.+Z  
output.writeInt(nStartPos.length); W{%M+a[#l  
for(int i=0;i<nStartPos.length;i++) 0 [s1!Cm!i  
{ D^pAf/ek@i  
// output.writeLong(nPos); |:AjQ&PM)  
output.writeLong(fileSplitterFetch.nStartPos); T@L
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output.writeLong(fileSplitterFetch.nEndPos); ?h5Y^}8Qg  
} 8n56rOW!  
output.close(); m+L:\mvA  
} ;,<s'5icyg  
catch(IOException e){e.printStackTrace ();} B::vOg77  
catch(Exception e){e.printStackTrace ();} ,yC~{H  
} &CS=*)>$  
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//读取保存的下载信息（文件指针位置） 5\pizD/17  
private void read_nPos() tIg_cY_y  
{ 3TJNlS  
try{ ^t| %!r G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); cD 1p5U  
int nCount = input.readInt(); $HaM, Oh;i  
nStartPos = new long[nCount];  z\\MLyS  
nEndPos = new long[nCount]; b_B4  
for(int i=0;i<nStartPos.length;i++) L U7.  
{ (*p |Kzu  
nStartPos = input.readLong(); hfY2pG9N  
nEndPos = input.readLong(); ! _QU-  
} 6K,AQ.=V2  
input.close(); )t|M)zJ  
} ].$N@tC  
catch(IOException e){e.printStackTrace ();} :5dq<>~  
catch(Exception e){e.printStackTrace ();} //`X+[bMG  
} 7 `|-
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(LnKaf8  

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private void processErrorCode(int nErrorCode) $(GXlhA  
{ 1(-)$m8}  
System.err.println("Error Code : " + nErrorCode); ZqSczS7uf  
} i6[Hu8  
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oRCj]9I$  
//停止文件下载 XX+4X*(o  
public void siteStop() ^mH^cP?/  
{ \=w|Zeu{l  
bStop = true; ^JH 4: h  
for(int i=0;i<nStartPos.length;i++) rx%lL  
fileSplitterFetch.splitterStop(); +] Fdg
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NL1Ajms`  
} ]":PO4M$*  
} ,Q^.SHP8  
//负责部分文件的抓取 }4$UlTA'  
**FileSplitterFetch.java ZM\Z2L]n  
*/ WzF/wzR  
package NetFox; iZ&CE5+  
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import java.io.*; LnLuWr<;}  
import java.net.*; o_{-X 1w  
]@
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/CH*5w)1   
public class FileSplitterFetch extends Thread { 6z~6o0s~  
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String sURL; //File URL ?xIwQd0  
long nStartPos; //File Snippet Start Position Lb(=:Z!{  
long nEndPos; //File Snippet End Position @<h@d_8^k  
int nThreadID; //Thread's ID H>2)R7h  
boolean bDownOver = false; //Downing is over  \\6/"  
boolean bStop = false; //Stop identical PKm
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FileAccessI fileAccessI = null; //File Access interface mkgDg y  
6?r}bs6Msx  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2WqjNqx)6  
{ ^`ny]3JA
 
this.sURL = sURL; ?8pRRzV$  
this.nStartPos = nStart; c1c8):o+V  
this.nEndPos = nEnd; )A,MTi  
nThreadID = id; 7V?TLGgd$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \#L}KW  
} (r.[b  
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public void run() rQCj^=cf;~  
{ Ean #>h  
while(nStartPos < nEndPos && !bStop) ht)J#Di  
{ [8[g_  
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try{ 'V/+v#V+>  
URL url = new URL(sURL); eX>x +]l6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U8 '}(  
httpConnection.setRequestProperty("User-Agent","NetFox"); `bNY[Gv>)  
String sProperty = "bytes="+nStartPos+"-"; #R}sGT  
httpConnection.setRequestProperty("RANGE",sProperty); 4'[/gMUkw  
Utility.log(sProperty); s>ilxLSX]  
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'_>8_  
InputStream input = httpConnection.getInputStream(); ^i:%0"[*^i  
//logResponseHead(httpConnection); qi!+Ceo}  
5NHNnDhuL  
3,t3\`=  
byte[] b = new byte[1024]; <<4U:  
int nRead; yJNQO'wcv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @X5F$=aqZr  
{ d[=~-[  
nStartPos += fileAccessI.write(b,0,nRead); JYc;6p$<i  
//if(nThreadID == 1) $9bLD >.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); c<Fr^8  
} /?VwoSgV^  
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Utility.log("Thread " + nThreadID + " is over!"); ^zn&"@  
bDownOver = true; J#ujIe  
//nPos = fileAccessI.write (b,0,nRead); QY|Rz(;m  
} hT go  
catch(Exception e){e.printStackTrace ();} 3RJsH:u8  
} vq/3
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} (l}W\iB'd  
'*lVVeSiFw  
 >cw%ckE  
//打印回应的头信息 2!QQypQ  
public void logResponseHead(HttpURLConnection con) /-s-W<S[  
{ ZW7z[,tk<.  
for(int i=1;;i++) nHyqfd<V>  
{ 4h~CDy%_  
String header=con.getHeaderFieldKey(i); ip8%9fG\>  
if(header!=null) fRh}n ^X  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ZD~ra7  
Utility.log(header+" : "+con.getHeaderField(header)); {
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else :8=7)cW  
break; gjFpM.D-.  
}
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} y!eT>4Oyg  
>\[/e{Q"  
;S0Kf{DN2  
public void splitterStop() JCFiKt9n  
{ Dk%+|c  
bStop = true; }l"pxp1K  
} Ui|z#{8&  
}ff+RGxLIG  
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} Nk2n&(~$  
rel_Z..~  
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/* lWPh2k  
**FileAccess.java YpJJ]Rszg  
*//文件访问(定位，写) VDT.L,9  
package NetFox; tzJ7wXRr  
import java.io.*; aGBUFCCa  
u43W.4H13  
z|bAZKSRYx  
public class FileAccessI implements Serializable{ n,D&pl9f  
g^I?u$&E  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 hU'h78bt(  
RandomAccessFile oSavedFile; Xrl# DN
 
long nPos; L0.F}~S  
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 T_)G5a  
public FileAccessI() throws IOException *(E]]8o  
{ )sN}ClgJ  
this("",0); {'cm;V+  
} fj|X`,TiZ;  
tJ$gH;  
2Y>#FEW/  
public FileAccessI(String sName,long nPos) throws IOException 4ibOVBG:*,  
{ #?"^:,Y  
oSavedFile = new RandomAccessFile(sName,"rw"); OMfw#  
this.nPos = nPos; L.2!Q3&  
oSavedFile.seek(nPos); ^|%
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} r(j:C%?}C  
;W{2\ Es  
+?)R
}\\  
public synchronized int write(byte[] b,int nStart,int nLen) #(7^V y&  
{ 'pj*6t1~  
int n = -1; 18,;2Sr44  
try{ b|pp}il  
oSavedFile.write(b,nStart,nLen); u.ej<Lo  
n = nLen;
!mH !W5&  
} w"{mDL}c  
catch(IOException e) XFSHl[uS1  
{ +I3j2u8L  
e.printStackTrace (); i0nu5kD+d  
} ?t)Mt]("  
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@d|3c7` A  
return n; 2Q%*` vCuV  
} U4=m>Ty  
 qC6@  
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} ZZM;%i-B  
+;T\:'CU  
j-#h^3l1?  
/* BD- c<K"  
**SiteInfoBean.java Dy&{PeE!  
*/ 5[LDG/{Tys  
package NetFox; BdB9M8fM  
6<fcG  
";jKTk7  
public class SiteInfoBean { h0] bIT{  
\ [bJ@f*."  
mWF\h>]|.  
private String sSiteURL; //Site's URL {8 #  
private String sFilePath; //Saved File's Path |G)P I`BH  
private String sFileName; //Saved File's Name {ub'   
private int nSplitter; //Count of Splited Downloading File V%'' GF   
L8J] X7  
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public SiteInfoBean() .=N?;i  
{//nSplitter的缺省值为5 )# v}8aL  
//default value of nSplitter is 5 ka@yQ
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this("","","",5); qND:LP\_v  
} SohNk9u[8  
E|3[$?=R  
/ hg)=p  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) r{{5@  
{ @6M>x=n5  
sSiteURL= sURL; xFcW%m>9C  
sFilePath = sPath; ):\+%v^  
sFileName = sName; 5?A<('2  
this.nSplitter = nSpiltter; `(r0+Qx  
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+~EnrrT+W  
} ;6$W-W _  
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public String getSSiteURL() To
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{ p7W9?b9  
return sSiteURL; 0ybMI+*  
} BoXPX2:  
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Yyw9IYB;  
public void setSSiteURL(String value) @"B{k%+  
{ ~x[(1  
sSiteURL = value; GL _hRu  
} J| 1!4R~  
!D!"ftOm  
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public String getSFilePath() I+QM":2  
{ xt6%[)  
return sFilePath; 3L-$+j~u  
} 'Z|Czd8E  
^U);MH8  
O;$}j:;KF  
public void setSFilePath(String value) .e4upTGU  
{ +i[@+`  
sFilePath = value; v|dt[>G  
} b'I@TLE')  
3lbGG42:  
<E:_9#Z0sc  
public String getSFileName() R[kF(C&  
{ #7"";"{z|  
return sFileName; J\FLIw4  
} oBs5xH7@-  
G^Y^)pc]   
)LsUO#%DO  
public void setSFileName(String value) *to#ZMR;!  
{ i*8j|  
sFileName = value; If
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} ]z]=?;ty%  
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t>Yl=79,  
public int getNSplitter() ix38|G9U  
{ qeC^e}h  
return nSplitter; oN)I3wO$  
} RRro.
r,  
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public void setNSplitter(int nCount) VtMnLFMw  
{ $ nMx#~>a  
nSplitter = nCount; 7q:;3;"9  
} pU<GI@gU  
} F$'po#  
KO/#
t~  
6\Tq,I7  
/* B`w8d[cL7  
**Utility.java WR u/7$8  
*/ {].]`#4Jx  
package NetFox; JEK_W<BD  
(=j/"
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qiq=v)  
public class Utility { O|+$9#,  
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public Utility() >p`i6_P0P/  
{ \=$G94%  
;2[OI  
TW wE3{iF  
} n'?]_z<  
#GfM^sK  
//线程睡眠 wKoar  
public static void sleep(int nSecond) 6B Hdc  
{ 6W~JM^F  
try{ X5-[v(/]  
Thread.sleep(nSecond); BqpJvRJd  
} L=.@hs  
catch(Exception e) 6G(K8Q{>  
{ .yHK  
e.printStackTrace (); FbH@qHSH  
} ;kZJnN"y  
} Q(R-8"  
?X\uzu  
//日志 n]nJ$u1u  
public static void log(String sMsg) )TBm?VMe  
{ =`2jnvx  
System.err.println(sMsg); +Y2D @K?)  
} :GFK |  
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q"WfKz!U  
public static void log(int sMsg) D( y c  
{ #TV #*  
System.err.println(sMsg); o=PW)37>  
} Q'Uv5p"X  
} 7UqDPEXU]`  
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/* eT?vZH[N  
**TestMethod.java sQ&<cBs2  
*/ C0khG9,BL  
package NetFox; 7W+{U02O  
:G=ol2Q  
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@  
public class TestMethod { r1z+yx  
m:k;?p:x  
[.$/o}  
public TestMethod() p9!jM\(  
{ ///xx/weblogic60b2_win.exe ')iyD5/4  
try{ ?;Da%VS3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); K.Cx 9  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [#AI!-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 7\H_9o0$  
fileFetch.start(); vg1E@rH
|}  
} twt's,dO  
catch(Exception e){e.printStackTrace ();} WpMm%G~'4t  
'5A&c(
  
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} z uo:yaO  
 B`vC>  
@PK 1  
public static void main(String[] args) 3ly]DTbz  
{ >u|4490<0  
new TestMethod(); G
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} HcV,r,>e  
} &o&}5Aba9  
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