http断点续传简单实现（java)

/* c"jhbH!u4  
**SiteFileFetch.java ?j ;,q  
*/ OmQuAG ^\x  
package NetFox; oD|+X/FK  
import java.io.*; cc#_acR  
import java.net.*; `jl. f  
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public class SiteFileFetch extends Thread { k/6Gj}l'o  
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 Q}`2Y^.  
SiteInfoBean siteInfoBean = null; //文件信息Bean )@};lmPR  
long[] nStartPos; //开始位置 u+"hr"}${  
long[] nEndPos; //结束位置 8wNU2yH+D  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 bC>yIjCTn  
long nFileLength; //文件长度 ~S~x@&yR  
boolean bFirst = true; //是否第一次取文件 ESXU, qK]v  
boolean bStop = false; //停止标志 TbSt{TX  
File tmpFile; //文件下载的临时信息 ff2.|20  
DataOutputStream output; //输出到文件的输出流 RaJ}>e  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） n$Oky-P"  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^~hhdwu3a  
{ _a:!U^4  
siteInfoBean = bean; `~s,W.Eu4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =Am*$wGI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7xa@wa?!L  
if(tmpFile.exists ()) >H]|A<9u(  
{ g#bfY=C  
bFirst = false; CuGOjQ-k~  
read_nPos(); 5>^ W}0s  
} jmwQc&  
else ^Xz`hR   
{ LxYM"_1A;  
nStartPos = new long[bean.getNSplitter()]; azATKH+j  
nEndPos = new long[bean.getNSplitter()]; B3k],k  
} `qy6qKl N  
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} js$a^6
 
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public void run() R,b O{2O  
{ TW;;OS[  
//获得文件长度 Eo3Aak o  
//分割文件 D-\'P31  
//实例FileSplitterFetch "YJ;-$rb  
//启动FileSplitterFetch线程 (2a"W`  
//等待子线程返回 bm]dz;ljh  
try{ `E1_S  
if(bFirst) "Z1&z-   
{ >ehWjL`8  
nFileLength = getFileSize(); I}CA-8  
if(nFileLength == -1) 0jx~_zq-j  
{ ():?FJM  
System.err.println("File Length is not known!"); 5In8VE !P  
} GzE3B';g
 
else if(nFileLength == -2) %l$&_xV
-  
{ (YWc%f4  
System.err.println("File is not access!"); 4m~stDlN  
} 2wimP8  
else )*AA9   
{ x;b+gIz*  
for(int i=0;i<nStartPos.length;i++) f4;8?  
{ 7XI4=O};&%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5@r Zm4U  
} fbbl92p  
for(int i=0;i<nEndPos.length-1;i++) i)^ZH#Gp  
{ | 3/p8  
nEndPos = nStartPos[i+1]; |$-d,] V  
} -JW6@L@  
nEndPos[nEndPos.length-1] = nFileLength; .j$bCKXGx  
} M:q;z(  
} ""KN?qh9  
*'S%gR=Aa+  
}(7QJk5 j  
//启动子线程 D0_x|a  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; g(F*Y>hk  
for(int i=0;i<nStartPos.length;i++) h],%va[  
{ K*i1! "w  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ac(Vw%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4I[FE;^  
nStartPos,nEndPos,i); E3C[o! 5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^cXL4*_=  
fileSplitterFetch.start(); |@9I5Eg)iE  
} &@Gu~)^(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s7cyo ]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~;4k UJD  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", zNTu j p  
nEndPos = " + nFileLength); B*?PB]  
// fileSplitterFetch[nPos.length-1].start(); (+v*u]w4  
wuCtg=  
[";5s&)q  
//等待子线程结束 7%x+7  
//int count = 0; tcdn"]#U  
//是否结束while循环 ^%/5-0?xE  
boolean breakWhile = false; aI#n+PW  
'ah0IYe  
'/*rCB  
while(!bStop) ?cxK~Y\  
{ }4ju2K  
write_nPos(); a9_KQ=&CI  
Utility.sleep(500); JBJ7k19;  
breakWhile = true; 40sLZa)e  
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%H~gN9Vn#@  
for(int i=0;i<nStartPos.length;i++) 5WN Z7cO  
{ ; SM^  
if(!fileSplitterFetch.bDownOver) 13az[  
{ NKh{iSLm  
breakWhile = false; :|mkI#P.  
break; :pu{3-n.  
} %hb5C 4q  
} RL)3k8pk  
if(breakWhile) d*(\'6?  
break; \uPTk)oaB  
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I*R$*/)  
//count++; Oydmq,sVe(  
//if(count>4) CXFAb1m  
// siteStop(); oVsazYJ|?  
} ,
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System.err.println("文件下载结束！"); V-r<v1}M  
} Z69IHA[  
catch(Exception e){e.printStackTrace ();} bbkI}d%(Ng  
} >U/g*[>  
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|;-r};  
//获得文件长度 L2$L.@  
public long getFileSize() sYP@>tHC  
{ MW>28  
int nFileLength = -1; j]D =\  
try{ ,FVy:"FR  
URL url = new URL(siteInfoBean.getSSiteURL()); W+S; Do  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0l@+xS;  
httpConnection.setRequestProperty("User-Agent","NetFox"); [k}\{i>  
}]?G"f t K  
gQDK?aQX  
int responseCode=httpConnection.getResponseCode(); i?=.; 0[|  
if(responseCode>=400) rB?c
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{ kweTK]mT  
processErrorCode(responseCode); 6x{IY  
return -2; //-2 represent access is error jdf@lb=5l  
} Z!eq/  
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String sHeader; I*2rS_i[T  
#L$ I%L"  
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for(int i=1;;i++) 2:F  
{ "?,6{\y,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (\>'yW{f  
//Utility.log(in.readLine()); `{_PSzM  
sHeader=httpConnection.getHeaderFieldKey(i); Rw 8o]  
if(sHeader!=null) ZHasDZ8  
{ +eXfT*=u5  
if(sHeader.equals("Content-Length")) 0Wm-`ZA  
{ S$WM&9U  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); elB 8   
break; Zw{tuO7}K  
} w5jZI|  
} mh]$g<*m  
else r/2:O92E  
break; `0D1Nh"%k  
} uJ\Nga<?  
} D:EF@il  
catch(IOException e){e.printStackTrace ();} V~Lq,oth  
catch(Exception e){e.printStackTrace ();} `ay
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#wiP{+%b  
3Q)>gh*
 
Utility.log(nFileLength); sdD[`#  
= h( n+y<  
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return nFileLength;
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} D.`\ ^a  
1?\
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//保存下载信息（文件指针位置） 7k|(5P;  
private void write_nPos() @~3c;9LkY  
{ 3wl>a#
f  
try{ i@L2W>{P  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /)T
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output.writeInt(nStartPos.length); }}1Q<puM  
for(int i=0;i<nStartPos.length;i++) V}-o):dI|  
{ -~fI|A^  
// output.writeLong(nPos); ~\,6C1M  
output.writeLong(fileSplitterFetch.nStartPos); _6 `4_<c=  
output.writeLong(fileSplitterFetch.nEndPos); yRkMR$5&  
} QGy=JHb  
output.close(); tvRy8u;
 
} UV.9KcN.  
catch(IOException e){e.printStackTrace ();} 5 ZPUY  
catch(Exception e){e.printStackTrace ();} x~eEaD5m%J  
} nDy=ZsK  
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//读取保存的下载信息（文件指针位置） "cM5=;  
private void read_nPos() ^mQfXfuL  
{ y@_?3m7B=  
try{ ~#\#!H7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); q2vz#\A?  
int nCount = input.readInt(); He3zV\X[Z  
nStartPos = new long[nCount]; q/79'>`|ai  
nEndPos = new long[nCount]; 4&fnu/,Z  
for(int i=0;i<nStartPos.length;i++) =i?,y+<  
{ v19`7qgR(  
nStartPos = input.readLong(); l.l~K%P'h  
nEndPos = input.readLong(); f34&:xz2U  
} J7o?h9  
input.close(); Xs@ ^D,  
} 5V!XD9P'  
catch(IOException e){e.printStackTrace ();} 12dW:#[  
catch(Exception e){e.printStackTrace ();} |
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} :`1g{8.+  
eCD,[At/  
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private void processErrorCode(int nErrorCode) f@L{*Upj+  
{ b%j:-^0V  
System.err.println("Error Code : " + nErrorCode); BwD1}1jp  
} ^/vWK\-  
sb.SpF>   
krc!BK`V  
//停止文件下载 ^#se4qQ  
public void siteStop() -74T C  
{ |3ETF|)?  
bStop = true; $t'I*k^N  
for(int i=0;i<nStartPos.length;i++) |Eu~=J7@  
fileSplitterFetch.splitterStop(); [zE
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. *xq =  
ped Yf{T  
} HYmXPpse  
} hATy3*4  
//负责部分文件的抓取 %Oqe7Cx>+  
**FileSplitterFetch.java k|'Mh0G0  
*/ caD;V(  
package NetFox; va2A@
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import java.io.*; =A6O}0z  
import java.net.*; %=y3  
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public class FileSplitterFetch extends Thread { 1Z8oN3  
] Nipo'N;  
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String sURL; //File URL ;@~*z4U  
long nStartPos; //File Snippet Start Position :Xh`.*{EX  
long nEndPos; //File Snippet End Position QC,(rB  
int nThreadID; //Thread's ID KdsvZim0>  
boolean bDownOver = false; //Downing is over "e<. n  
boolean bStop = false; //Stop identical z}8L}:  
FileAccessI fileAccessI = null; //File Access interface :=v{inN  
#q.G_-H4J@  
b)^ZiRW``  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException u?Mu*r?  
{ $OoN/^
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this.sURL = sURL; ld:alEo  
this.nStartPos = nStart; ~ O=|v/]  
this.nEndPos = nEnd; )^f Q@C8  
nThreadID = id; R9G)X]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9yw/-nA  
}
pu*u[n  
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public void run() g@VndAp  
{ _rdj,F8  
while(nStartPos < nEndPos && !bStop)
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{ <dPxy`_  
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try{ [j U  
URL url = new URL(sURL); lILtxVBO2o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F>(#Af9  
httpConnection.setRequestProperty("User-Agent","NetFox"); BG0Mj2  
String sProperty = "bytes="+nStartPos+"-"; v/.h%6n?  
httpConnection.setRequestProperty("RANGE",sProperty); u;qMo`-  
Utility.log(sProperty); ~
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InputStream input = httpConnection.getInputStream(); qpqz. {\  
//logResponseHead(httpConnection); 7qK0!fk5  
3N0X?* (x|  
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byte[] b = new byte[1024];
Mr,y|   
int nRead; <;E[)tv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) m{dyVE  
{ (jMAa%
  
nStartPos += fileAccessI.write(b,0,nRead); Cf=q_\0|W  
//if(nThreadID == 1) E816YS='  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _s-HlE?C  
} 5po'(r|U  
e0WSHg=6@  
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Utility.log("Thread " + nThreadID + " is over!"); =C>`}%XT}  
bDownOver = true; zQ %z"tQ  
//nPos = fileAccessI.write (b,0,nRead); U3+_'"  
} <i\zfa'6  
catch(Exception e){e.printStackTrace ();} \"`>-v"h
 
} UAXF6
4w{  
} GKujDx+h  
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rspoSPnY1  
//打印回应的头信息 3kqV_Pjg  
public void logResponseHead(HttpURLConnection con) xZ=FH>Y6'  
{ 8w8I:*  
for(int i=1;;i++) Fxth>O`$  
{ j[J@tM#  
String header=con.getHeaderFieldKey(i); ]{2{:`s  
if(header!=null) 0ij~
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); X$|TN+Ub  
Utility.log(header+" : "+con.getHeaderField(header)); !eAdm  
else kbp( a+5  
break; ={E!8"  
} 6
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} p@7i=hyt`p  
*(&ClUQQ  
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public void splitterStop() tGO[A#9a  
{ ^A"lkV7  
bStop = true; K l0tyeT  
} -wRyMY_D  
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qz=#;&ZU  
} <r+!hJ[s'  
,*nZf|  
g y e(/N+I  
/* xV>iL(?  
**FileAccess.java [bi3%yWh  
*//文件访问(定位，写) vMZ7uO  
package NetFox; L_lDFF  
import java.io.*; NBqV0>vR  
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public class FileAccessI implements Serializable{ k Kp6  
bxhg*A  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节
yLgKS8b  
RandomAccessFile oSavedFile; 2}Z4a\YX  
long nPos; ',H$
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public FileAccessI() throws IOException !V]MLA`  
{ *bxJ)9B  
this("",0); }6CXJ+-UR  
} N;x<| %peL  
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9I\  
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public FileAccessI(String sName,long nPos) throws IOException si^4<$Nr%j  
{ Z`oaaO
 
oSavedFile = new RandomAccessFile(sName,"rw"); Od!F
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this.nPos = nPos; eN]>l  
oSavedFile.seek(nPos); )zW%\s*
'  
} 5rfH;`  
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public synchronized int write(byte[] b,int nStart,int nLen) Q$fRi[/L  
{ *TM;trfz  
int n = -1; ksu}+i,a  
try{ #6N+5Yx_[  
oSavedFile.write(b,nStart,nLen); AvrL9D  
n = nLen; 'wz\tT^  
} o=-Vt,2{  
catch(IOException e) b\?7?g  
{ ljYpMv.>xG  
e.printStackTrace (); . Z*j!{@c  
} # cN_y  
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return n; BSfm?ku"!  
} tM^;?HL]  
~MhgAC  
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} !EX?m }7  
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/* ePq13!FC/  
**SiteInfoBean.java cebs.sF:  
*/ gV"qV  
package NetFox; `dv}a-Q)c  
/ojO>Y[<   
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public class SiteInfoBean { TvunjTpaj  
m"gni #  
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private String sSiteURL; //Site's URL h"%|\o+3  
private String sFilePath; //Saved File's Path yV:EK{E  
private String sFileName; //Saved File's Name :DdBn.  
private int nSplitter; //Count of Splited Downloading File ]6t]m2~\  
n+{HNr  
'yPCZ`5H(  
public SiteInfoBean() #`jE%ONC  
{//nSplitter的缺省值为5 jl.okWuiY  
//default value of nSplitter is 5 bBUbw*DF)  
this("","","",5); lAdDu  
} 1B)Y;hg6&  
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PIZ C;K4|  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &1
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{ oA4D\rn8"  
sSiteURL= sURL; $!YKZ0)B'0  
sFilePath = sPath; 0'?V|V=v  
sFileName = sName; vKNt$]p
m=  
this.nSplitter = nSpiltter; q2x|%HRF  
 4%g6_KB  
AbUDn\0$  
} )7&42>t  
{&2$[g=[ ^  
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public String getSSiteURL() Sa3I?+  
{ B{7Kzwh;  
return sSiteURL; 1.# |QX  
} "?apgx 6  
]\CU9J|H8  
T4OguP=  
public void setSSiteURL(String value) tg.|$n  
{ %55@3)V8Rf  
sSiteURL = value;
t"<s}~  
} I jZ]_*^!  
$_Y/'IN`k  
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public String getSFilePath() WnD^F>  
{ @S
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return sFilePath; m7$8k@r  
} *#3*;dya]  
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wL4ZW8_  
public void setSFilePath(String value) 2R^O,Vu*W  
{ s%eyW _  
sFilePath = value; wgCvD  
} w3^NL(>  
9YR]
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P
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public String getSFileName() ePf+[pV3  
{ Dc08D4   
return sFileName; (+|X<Bl:`  
} LmP qLH'(Q  
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YiD-F7hf.*  
public void setSFileName(String value)  )|v^9  
{
8RVS)D''  
sFileName = value; "mP&8y9F  
} -x{dc7y2  

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/-h6`@[  
public int getNSplitter() z5x _fAT(  
{ >A-<ZS*N  
return nSplitter; b9!.-^<8y  
} AgIazv1  
gX[|;IZ0o  
XMGx^mn  
public void setNSplitter(int nCount) /QQ8.8=5  
{ LH4>@YPGE#  
nSplitter = nCount; ~A6"sb=  
} {J (R  
} KkEv#2n  
A]7<'el=  
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/* yQ9ZhdQS  
**Utility.java Mtm/}I  
*/ pe9@N9_5  
package NetFox; d')-7C  
sONBQ9  
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public class Utility { g& k58{e  
)l_@t(_  
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public Utility() ~4Pc_%&i  
{ Ht#@'x  
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} &uv0G'"\  
bp#:UUO%S  
//线程睡眠 2R]&v;A  
public static void sleep(int nSecond) J{`eLmTu  
{ !22yvT.;[  
try{ 6SVqRD<`  
Thread.sleep(nSecond); 6xoq;=o  
} 'n0 .#E_  
catch(Exception e) VU|;:  
{ [8"ojhdV  
e.printStackTrace (); oBA`|yW{U  
} D==Mb~  
} FXV`9uq}Z  
$J.T$0pFa  
//日志 nU(DYHc+l  
public static void log(String sMsg) I^D0<lHl~  
{ w1r$='*I  
System.err.println(sMsg); 'CXRG$
D  
} %K(0W8&  
1j0-9Kg'  
z>;$im  
public static void log(int sMsg) JQ@fuo %  
{ Gih[i\%Q  
System.err.println(sMsg); _tAQ=eBO  
} &-%X:~|:X  
} . w H*sb  
Y#FO5O%W  
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/* Q6IQV0{p  
**TestMethod.java ,LZX@'5  
*/ =p@8z /u  
package NetFox; B
6]<G-
 
H2
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HSN8O@dy  
public class TestMethod { 8!mc@$Z  
I;7nb4]AmF  
1tB[_$s  
public TestMethod() BByCMY  
{ ///xx/weblogic60b2_win.exe a{SBC
y  
try{ B&Y_2)v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 2 -Xdoxw  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);
wvMW|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); cu&,J#r%  
fileFetch.start(); zP!J/}z  
} >O7~h[FN  
catch(Exception e){e.printStackTrace ();} p@YB?#Im  
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PWB(5 f?  
} 7\XE,;4>  
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"w_N'-}#  
public static void main(String[] args) -"Q-H/qh  
{ 9 [jTs3l:  
new TestMethod(); 5,pSg  
} %zeATM[`  
} C`V)VJM  
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