http断点续传简单实现（java)

/* `g~T #U\>d  
**SiteFileFetch.java faqh }4
 
*/ bq}hj Cy  
package NetFox; piy_9nk  
import java.io.*; ;FI"N@z  
import java.net.*; kCuIEv@  
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public class SiteFileFetch extends Thread { ivi,/~L  
/HiRbwQK#  
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SiteInfoBean siteInfoBean = null; //文件信息Bean > ]()#
z  
long[] nStartPos; //开始位置 EAE\'9T&g  
long[] nEndPos; //结束位置 REaU=-m-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ~\C.Nm  
long nFileLength; //文件长度 ^rP` .Z  
boolean bFirst = true; //是否第一次取文件 AfV a[{E  
boolean bStop = false; //停止标志 Hyj<Fqr!.  
File tmpFile; //文件下载的临时信息 Vw P+tM  
DataOutputStream output; //输出到文件的输出流 <,Z6=M
`  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） YR\pt8(z?  
public SiteFileFetch(SiteInfoBean bean) throws IOException $v
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{ WF!u2E+  
siteInfoBean = bean; Kj+=?R~}S  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); $vQ#ah/k  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); |oL}c!0vs  
if(tmpFile.exists ()) .8I\=+Zi  
{ T*'?;u  
bFirst = false; %~$P.Zh  
read_nPos(); >3J?O96|f  
} M|l`2Hpe  
else >0kZ-M5  
{ q7!$-  
nStartPos = new long[bean.getNSplitter()]; pod=
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nEndPos = new long[bean.getNSplitter()]; foi@z9  
} "PI]k  
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} <Y9 L3O`[  
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public void run() <NVSF6`  
{ Uql|32j  
//获得文件长度 1J tt\yq  
//分割文件 r*gQGvc  
//实例FileSplitterFetch (/oHj^>3N`  
//启动FileSplitterFetch线程 z(yJ
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//等待子线程返回 {imz1g;  
try{ H fg2]N  
if(bFirst) @+,J^[ y  
{ h>A~..  
nFileLength = getFileSize(); 5Lo\[K>j  
if(nFileLength == -1) X`n)]~  
{ v"po}K  
System.err.println("File Length is not known!"); Ew9\Y R}  
} R[l9f8  
else if(nFileLength == -2) .>.B  
{ NukcBH  
System.err.println("File is not access!"); .0[ zZ  
}
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else 2A5R3x=\  
{ |IL/F]I  
for(int i=0;i<nStartPos.length;i++) n*Q~<`T  
{ Q=+*OQV29  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l[G&=/R@H  
} h:J0d~u  
for(int i=0;i<nEndPos.length-1;i++) hyPVt6Gkj  
{ t\/i9CBn  
nEndPos = nStartPos[i+1]; f2abee  
} {&bjjM  
nEndPos[nEndPos.length-1] = nFileLength; =[7[F)I~O  
} DF>LN%a~  
} A
5A4*.C  
+;ILj<!Z7  
KO~_  
//启动子线程 :L E&p[^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; a(qij&>  
for(int i=0;i<nStartPos.length;i++) ;nDCyn4i]  
{ 3kc.U  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), zOEdFU{x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), R;6$lO8C&  
nStartPos,nEndPos,i); m4=[e!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qVvQ9?  
fileSplitterFetch.start(); 8H%-/2NW  
} WFYbmfmV  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  3)bC,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [i&EUvo  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lHTW e'  
nEndPos = " + nFileLength); Pa8E.<>  
// fileSplitterFetch[nPos.length-1].start(); ^ |xSU_wa  
rQuozbBb  
.
/
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//等待子线程结束 b#17N2xkT  
//int count = 0; u@"nVHgMJ  
//是否结束while循环 a (mgz&*  
boolean breakWhile = false; )yOdRRP  
9HtzBS  
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while(!bStop) yq
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{ b `7vWyp  
write_nPos(); wOlnDQs  
Utility.sleep(500); ixf~3Y8  
breakWhile = true; =`1#fQDt  
08+cNT  
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for(int i=0;i<nStartPos.length;i++) s.zfiJ
 
{ nz?jNdyz  
if(!fileSplitterFetch.bDownOver) x3`b5^  
{  wh
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breakWhile = false; EGY'a*]cU  
break; G~ldU: ?  
} @lYm2l^  
} h8
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if(breakWhile) Ci}v+  
break; +i@r-OL  
2$fFl,v!z  
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//count++; C,;hNg[  
//if(count>4) ]z
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// siteStop(); 5Dhpcgq<<  
} {D6E@a  
>\/H2j  
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System.err.println("文件下载结束！"); (F<VcB  
} aT]G&bR?  
catch(Exception e){e.printStackTrace ();} n{b(~eL?  
} ;j#(%U]Vp  
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w[WyT`6h!  
//获得文件长度 6<uJ}3  
public long getFileSize() 8@}R_GZc  
{ +# 38  
int nFileLength = -1; tm"9`   
try{ Qh0tU<jG  
URL url = new URL(siteInfoBean.getSSiteURL()); /9K,W)h_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); AB.gVw| 4  
httpConnection.setRequestProperty("User-Agent","NetFox");  /z0X  
L,m'/}$  
:3uCW1  
int responseCode=httpConnection.getResponseCode(); hJkSk;^  
if(responseCode>=400) J0 [^hH  
{ `YK2hr  
processErrorCode(responseCode); j/oM^IY  
return -2; //-2 represent access is error =u*\P!$  
} |>Q]q  
}k`-n32)|  
*tWZ.I<<  
String sHeader; Y`O"+Jr  
fku\O<1  
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for(int i=1;;i++) FuWMVT`Y  
{ yU e7o4Zm  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Rr9K1io$)  
//Utility.log(in.readLine()); (.CEEWj%{  
sHeader=httpConnection.getHeaderFieldKey(i); 86bRfW'  
if(sHeader!=null) )@IDmz>  
{ @y|ZXPC#  
if(sHeader.equals("Content-Length")) S,=#b 4\#%  
{ AM[#AZv  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); MR) *Xh  
break; ?$ft3p}  
} \~LwlOo%R  
} ?
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else B"07:sO  
break; 8|Q=9mmWOh  
} j56#KNAha  
} :c*_W /  
catch(IOException e){e.printStackTrace ();} _F2R x@Y  
catch(Exception e){e.printStackTrace ();} U)f;*{U  
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Utility.log(nFileLength); #><P28m  
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return nFileLength; N=JZtf/i  
} -L.U4x  
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//保存下载信息（文件指针位置） 
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private void write_nPos() 2"'<Yk9  
{ ?!uj8&yyf  
try{ <]SI-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BA5b;+o-  
output.writeInt(nStartPos.length); ZFJqI  
for(int i=0;i<nStartPos.length;i++) o'Uaz*-po  
{ Ib~n}SA  
// output.writeLong(nPos); *VbB'u:  
output.writeLong(fileSplitterFetch.nStartPos); K5h2 ~  
output.writeLong(fileSplitterFetch.nEndPos); aX)k(*|  
} aJ4y%Gy?  
output.close(); fcim4dfP  
} >dr34=(  
catch(IOException e){e.printStackTrace ();} prdlV)LTpY  
catch(Exception e){e.printStackTrace ();} ]]EOCGZ"  
} $=
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6*{sZMG  
3eg)O34  
//读取保存的下载信息（文件指针位置） Wubvvm8U  
private void read_nPos() "-WEUz  
{ Bb~Q]V=x;  
try{ 4YT d  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ; qQ* p  
int nCount = input.readInt(); ^#V7\;v$G  
nStartPos = new long[nCount]; JKXb$  
nEndPos = new long[nCount]; ~!PaBS3A  
for(int i=0;i<nStartPos.length;i++) eB]R<a60  
{ =k{ n! e  
nStartPos = input.readLong(); Ai~j q  
nEndPos = input.readLong(); 60iMfcT  
} ~ ~"qT  
input.close(); t&oNC6  
} w@jC#E\  
catch(IOException e){e.printStackTrace ();} J%:D%=9 )  
catch(Exception e){e.printStackTrace ();} $GMva}@G`  
} (59u<F  
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]ZbZ]  
private void processErrorCode(int nErrorCode) f3p)Q<H>`(  
{ mBQp#-1\  
System.err.println("Error Code : " + nErrorCode); fH>I/%  
} jNC@b>E?~  
~8j4IO(  
.#4;em%7  
//停止文件下载 'a^'f]"  
public void siteStop() )R- e^Cb  
{ ) ]y^RrD  
bStop = true; JM&:dzyIP  
for(int i=0;i<nStartPos.length;i++) CY
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fileSplitterFetch.splitterStop(); $YPU(y  
HQ7  

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} 8iIz!l%O  
} k>'c4ay290  
//负责部分文件的抓取 3jJd)C R  
**FileSplitterFetch.java ` 465 H  
*/ 2JMMNpya  
package NetFox; -Y{=bZS u  
pSPVY2qKX  
(H_YYZ3ZX  
import java.io.*; B=R9K3f  
import java.net.*; 0wA?.~ L  
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public class FileSplitterFetch extends Thread { K,$Ro@!  
<*vWcCS1  
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String sURL; //File URL HTa]T'  
long nStartPos; //File Snippet Start Position fl4z'8P"(  
long nEndPos; //File Snippet End Position ,~TV/l<  
int nThreadID; //Thread's ID 3lw8%QD>  
boolean bDownOver = false; //Downing is over c:@lR/oe"  
boolean bStop = false; //Stop identical T+q3]&  
FileAccessI fileAccessI = null; //File Access interface ^p2_p9  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException mjI $z3  
{ U7(t >/  
this.sURL = sURL; mT3'kUZ}]  
this.nStartPos = nStart; z+=wql*Eo  
this.nEndPos = nEnd; #K4lnC2qz  
nThreadID = id; >}p'E9J?r  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4Gsbcl{  
} B.T|e,g26  
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public void run() ,iy;L_N  
{ Z'V"nhL  
while(nStartPos < nEndPos && !bStop) y?}R,5k  
{ ]rY3bG'&  
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try{ h=7eOK]  
URL url = new URL(sURL); `+c8
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _ft)e3Gf  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?04$1n:  
String sProperty = "bytes="+nStartPos+"-"; s7(I  
httpConnection.setRequestProperty("RANGE",sProperty); ,RYahu  
Utility.log(sProperty);
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InputStream input = httpConnection.getInputStream(); _]/&NSk  
//logResponseHead(httpConnection); M6MtE_E  
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byte[] b = new byte[1024]; aP}%&{iC*  
int nRead; h]w5N2$}?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _ITA$#  
{ 9si,z  
nStartPos += fileAccessI.write(b,0,nRead); mKh<M)Bz  
//if(nThreadID == 1) F VVpyB|  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LL}b]B[  
} M,WC+")Z=  
{-'S#04  
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Utility.log("Thread " + nThreadID + " is over!"); Rc.8j,]  
bDownOver = true; x#0B "{  
//nPos = fileAccessI.write (b,0,nRead); Q|1X|_hs  
} E{#Y=  
catch(Exception e){e.printStackTrace ();} !J%m7A  
} )tB1jcI;  
} f|cF
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//打印回应的头信息
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public void logResponseHead(HttpURLConnection con) 2TZ+R7B?  
{ -y1t;yU.L  
for(int i=1;;i++) Z,ZebS@yG  
{ #2U4}#Mi  
String header=con.getHeaderFieldKey(i); ]di9dLT  
if(header!=null) \~{b;$N}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); EvJ"%:bp  
Utility.log(header+" : "+con.getHeaderField(header)); Z7@~#)3  
else 45DR%cz  
break; w*-1*XNA  
} \@eC^D2  
} 7K\H_YY8#  
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public void splitterStop() S$egsK"~  
{ Ts~)0  
bStop = true; tc%0yr9  
} Zt7Gf  
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} ZR|cZH1}C  
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/* fmv8)$W#U  
**FileAccess.java =>Md>VM  
*//文件访问(定位，写) A8by5qU  
package NetFox; R/UL4R,)^  
import java.io.*; -1P*4H2a  
^1 P@BRh  
6?X)'  
public class FileAccessI implements Serializable{ 7Hm/g  
`Y5{opG7-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 k"V@9q;*  
RandomAccessFile oSavedFile; #VA8a=t  
long nPos; *G,'V,?  
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public FileAccessI() throws IOException aRh1Q=^@(4  
{ C*f3PB=H_  
this("",0); 'r2VWavT  
} 6IQkP9P(  
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public FileAccessI(String sName,long nPos) throws IOException ,svj(HP$  
{ nGdEJ  
oSavedFile = new RandomAccessFile(sName,"rw"); '+Gy)@c  
this.nPos = nPos; |k-IY]6  
oSavedFile.seek(nPos); :d5fU:  
} N+[ |"v  
|,G=k,?_p  
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public synchronized int write(byte[] b,int nStart,int nLen) 6}>:s
r  
{ -1>$3-ur~  
int n = -1; 8UANB]@Y}  
try{ 9j6  
oSavedFile.write(b,nStart,nLen); wB0zFlP  
n = nLen; @A-^~LoP.  
} 2\:z 
 
catch(IOException e) 51\N+  
{ ]("5O V5  
e.printStackTrace (); wv~?<DF
 
} yye(^  
)ZI9n7  
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return n; @Q=P6Rz {S  
} L< gp "e  
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} I9 R\)3"  
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/* ]q2g[D o5  
**SiteInfoBean.java Yom,{;B
v  
*/ MDo4{7  
package NetFox; hSvA dT]m  
O+o4E?}  
bLHj<AX#>|  
public class SiteInfoBean { #{t?[JUn  
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private String sSiteURL; //Site's URL d/Z258  
private String sFilePath; //Saved File's Path ?xTh}Sky  
private String sFileName; //Saved File's Name g7|$JevR0  
private int nSplitter; //Count of Splited Downloading File r:&"#F   
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ARZ5r48)  
public SiteInfoBean() $|2@of.  
{//nSplitter的缺省值为5 "?lm`3W"  
//default value of nSplitter is 5 @"`{gdB$  
this("","","",5); 2`o}neF{  
} J01Y%W  
#e!4njdM  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) x 7;Zwd  
{ y,*>+xk,  
sSiteURL= sURL; iuX82z`  
sFilePath = sPath; E/MNz}+  
sFileName = sName; JVORz-uBs  
this.nSplitter = nSpiltter; UI*^$7z1 +  
>}43xIRRCq  
H9["ZRL,Q  
} r*'X]q|L+  
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public String getSSiteURL() D{](5?$`|  
{ f|*vWHSM  
return sSiteURL; g*NKY`,  
} CTbz?Kn  
%("Bq"Q8  
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public void setSSiteURL(String value) cdDMV%V  
{ zKi5e+\  
sSiteURL = value; ;9{x""
 
} Kzs]+Cl  
k+"+s bsW'  
',MiD=_  
public String getSFilePath()
l#FW#`f  
{ _d
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return sFilePath; :.-z) C}  
} o|s JTY  
#L{+
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public void setSFilePath(String value) m})q8b!S  
{ a:oZ5PX=  
sFilePath = value; Sv7_-#SW<(  
} QL>G-Rp  
_)7dy2%{q  
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public String getSFileName() m\h/D7zg  
{ JeR8Mb  
return sFileName; r|XNS>V ,$  
} LiyEF&_u  
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public void setSFileName(String value) x9#>0 4s  
{ +$#YW5wy  
sFileName = value; C*}TY)8  
}
NX$S^Z\QI  
?I`BbT}  
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public int getNSplitter() CjzfU*G  
{ oRM,_  
return nSplitter; fb5]eec  
} 7L[HtwI  
|S5N$[  
6?/$K{AI  
public void setNSplitter(int nCount) <ByR!Y  
{ 8t$a8 PE  
nSplitter = nCount; t5z6{`  
} `L(AvSR  
} y)W.xR  
^|6%~jkD5  
W^2Q"c#
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/* {d\erG
(  
**Utility.java ()}B]?  
*/ 4]N`pD5  
package NetFox; 2kTLj2@o,  
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# E'g{.N  
public class Utility { Mj&f7IUO  
b9[KdVsT6^  
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public Utility() TqNEU<S/t  
{ yA%(!v5UT  
wSp1ChS k  
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} krTH<- P  
bA-=au?o5  
//线程睡眠 '#SacJ\L7  
public static void sleep(int nSecond) Q{Gi**<  
{ #,O<E@E  
try{ h:[PO6GdX  
Thread.sleep(nSecond); k--.g(
T  
} 0px@3/  
catch(Exception e) =KwG;25hX  
{ eR(PY{  
e.printStackTrace (); J!,5HJh1  
} ]6{G;f$  
} 29g("(}TK  
I"E5XVC);  
//日志 NDhHU#Q9  
public static void log(String sMsg) Wig
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{ >JFAE5tj&2  
System.err.println(sMsg); ^f{+p*i}:  
} uXuMt a*Y  
+XU*NAD,!  
NYD#I{h  
public static void log(int sMsg) [{_JO+)+n  
{ 6uQfe?aD  
System.err.println(sMsg); 9hI4',(rE  
} or/Y"\-!  
} y&\ J  
raGov`  
GEq?^z~i  
/* 8=Di+r  
**TestMethod.java @`U78)]  
*/ %@L(A1"#D  
package NetFox; lhAwTOn`Q  
lY_E=K]  
*k'oP~:fT  
public class TestMethod { XpWqL9s_E  
2RKI M(~  
g% :Q86u  
public TestMethod() 6OMywGI[Z  
{ ///xx/weblogic60b2_win.exe $=n|MbFl  
try{ /Cr0jWu _  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); z2og&|uT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); pYJv|`+  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &C3
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fileFetch.start(); /reSU 2  
} .:c^G[CQ^9  
catch(Exception e){e.printStackTrace ();} 7|3Z+#|T  
1i9}mzy%  
-[~UX!XFM  
} .O'S@ %]  
)cB00*/  
E/:<9xl  
public static void main(String[] args) ?gjM]Ki%:  
{  %"j<`  
new TestMethod(); lyKV^7}  
} RX:\@c&  
} YMnG-'^Z  
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