http断点续传简单实现（java)

/* }2<r,  
**SiteFileFetch.java Zw
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*/ #.it]Nv{  
package NetFox; ABF"~=aL  
import java.io.*; ,$+lFv3LE  
import java.net.*; c\iA89msp  
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public class SiteFileFetch extends Thread { (^@ra$.  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #cnq(S=.  
long[] nStartPos; //开始位置 V^JV4 `o  
long[] nEndPos; //结束位置 N F2/B#q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )=5ng-  
long nFileLength; //文件长度 3{ LP?w:@  
boolean bFirst = true; //是否第一次取文件 1y-y6q  
boolean bStop = false; //停止标志 ;ado0-VQi'  
File tmpFile; //文件下载的临时信息 T^w36}a  
DataOutputStream output; //输出到文件的输出流 LJ*q1 ;<E  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 5|l* `J)  
public SiteFileFetch(SiteInfoBean bean) throws IOException e?opkq\f  
{ "SzdDY6  
siteInfoBean = bean; 8S%52W|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); MZlk0o2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); BnCbon)  
if(tmpFile.exists ()) .C&ktU4  
{ SF&BbjBE0  
bFirst = false; Kz>3 ic$I  
read_nPos(); gUxP>hB  
} ? i( %  
else >}!mQpAO  
{ :X.b}^Z(  
nStartPos = new long[bean.getNSplitter()]; Ko;{I?c  
nEndPos = new long[bean.getNSplitter()]; 0}$Hi  
} CACTE  
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} R(2tlZ  
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public void run() ,17hGKM  
{ >+
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//获得文件长度 wW#}:59}  
//分割文件 )+}]+xRWGj  
//实例FileSplitterFetch ROk5]b.  
//启动FileSplitterFetch线程 ?\$#L^;b}  
//等待子线程返回 XLAN Np%E  
try{ FP;Ccl"s  
if(bFirst) &m|wH4\  
{ AT9q3  
nFileLength = getFileSize(); T-5nB>)  
if(nFileLength == -1) i|T)p_y(!a  
{ 5$wpL(:R(  
System.err.println("File Length is not known!"); 3H|_mX  
} 0BH_'ZW  
else if(nFileLength == -2) gA:5M  
{ t: #6sF  
System.err.println("File is not access!"); HuwU0:*  
} O)ME"@r@:  
else m9"n4a|:  
{ L5#P[cHzz  
for(int i=0;i<nStartPos.length;i++) tZ^Ou89:rG  
{ ~v]!+`_J  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); /C>wd   
} q~3,yyu  
for(int i=0;i<nEndPos.length-1;i++) FI3)i>CnW  
{ -PS#Z0>  
nEndPos = nStartPos[i+1]; \ C+(~9@|  
} 5m9*85Ib  
nEndPos[nEndPos.length-1] = nFileLength; (*oL+ef-C  
} Z00+!Tnd  
} H&]gOs3So  
9(6I<]#  
|1b
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//启动子线程 z)9wXo#~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  ^}:#  
for(int i=0;i<nStartPos.length;i++) ?r?jl;A&  
{ ^4,
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), iK12pw  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^my].Qpt  
nStartPos,nEndPos,i); Ti'}MC+0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7vABq(  
fileSplitterFetch.start(); ;gs ^%z  
} ,:??P1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j{NNSi3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /Wy.>YC|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 'Er:a?88l  
nEndPos = " + nFileLength); ]R=,5kK3  
// fileSplitterFetch[nPos.length-1].start(); mExVYp h  
5g9; +}X;  
RLSc+kDH_  
//等待子线程结束 BRk0CLr5  
//int count = 0; !OT-b>*w  
//是否结束while循环 :dLAs@z  
boolean breakWhile = false; cIp D~0\  
/r-aPJX  
`&-
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while(!bStop) 8Goh4T H  
{ Ay !G1;  
write_nPos(); *Mw_0Y  
Utility.sleep(500); 9:e YU =  
breakWhile = true; ~t^eiyv  
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for(int i=0;i<nStartPos.length;i++) bks/`rIA  
{ "m^' &L  
if(!fileSplitterFetch.bDownOver) ^`G`phd$  
{ TEMw8@b  
breakWhile = false; G 2mX;  
break; glDh([  
} MW PvR|Q  
} 2 ho>eRX  
if(breakWhile) )=-0M9e.{  
break; kdn'6>\  
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ak:ibV  
//count++; 8 O67  
//if(count>4) :_@JA0n  
// siteStop(); UQ[B?jc  
} fm^@i;D  
Y}[c^$S  
<}sq?Sfq!  
System.err.println("文件下载结束！"); cZ<A0  
} 8P"_#M?!  
catch(Exception e){e.printStackTrace ();} .58qL-iC  
} 4WE6fJ2X  
gt/zpiKmV  
;L,mBQB?0b  
//获得文件长度 fPrLM'  
public long getFileSize() &`fhEN  
{ {&"L~>/o  
int nFileLength = -1; QjC22lW-  
try{ tOOchu?=  
URL url = new URL(siteInfoBean.getSSiteURL()); iC*F
  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #^4,GLIM  
httpConnection.setRequestProperty("User-Agent","NetFox"); Vur bW=~g  
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int responseCode=httpConnection.getResponseCode(); o}<4*qlI  
if(responseCode>=400) (%U@3._  
{ E"L2&.  
processErrorCode(responseCode); 1Jj Y!  
return -2; //-2 represent access is error 06Gt&_Q  
} JKX_q&bUw  
cW{1 Pz^_  
iR\Hv'|  
String sHeader; D)@YI.T  
0jzbG]pc:E  
@o-B{EH8  
for(int i=1;;i++) l$YC/bP  
{ VL[kJi   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vAX|hwn;  
//Utility.log(in.readLine()); _ib"
b#  
sHeader=httpConnection.getHeaderFieldKey(i); #BQ.R,  
if(sHeader!=null) 3( ]M{4j  
{ 7c;9$j  
if(sHeader.equals("Content-Length")) OKHX)"j\\  
{ ^::E
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); P1zdK0TM  
break; FVKW9"AyW  
} MgC:b-&5_  
} T<I=%P)
 
else m] W5+  
break; uK'&Dam  
} !gLk
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} dVQ-
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catch(IOException e){e.printStackTrace ();} RI
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catch(Exception e){e.printStackTrace ();} fl;s9:<  
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Utility.log(nFileLength); :=9]c17=  
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return nFileLength; } %'bullT  
} k"N(o(  
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//保存下载信息（文件指针位置） Sggq3l$Qc  
private void write_nPos() 0oh]61gC  
{ E0/mSm"(T  
try{ Z--@.IYoJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); #UtFD^h  
output.writeInt(nStartPos.length); @VN&t:/l  
for(int i=0;i<nStartPos.length;i++) @Eb2k!T  
{ ~Xlrvb}LP  
// output.writeLong(nPos); x'zBK0i  
output.writeLong(fileSplitterFetch.nStartPos); l_j4DQBRV  
output.writeLong(fileSplitterFetch.nEndPos); O}[PJfvBHo  
} [I:KpAd/  
output.close(); y}v+c%d  
} &vovA} F  
catch(IOException e){e.printStackTrace ();} HK)cKzG[s!  
catch(Exception e){e.printStackTrace ();} {T'GQz+R"  
} K
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\]9.zlB  
//读取保存的下载信息（文件指针位置） !m(4F(!"h  
private void read_nPos() D{v8q)5r  
{ `p'Q7m2y/b  
try{ 7n o5b] \  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); XM<KF&pVB  
int nCount = input.readInt(); x"4} isp<  
nStartPos = new long[nCount]; \7z^!m  
nEndPos = new long[nCount]; Ke-)vPc  
for(int i=0;i<nStartPos.length;i++) =H8 xSJLh  
{ 4gSH(*}  
nStartPos = input.readLong(); b.O9ITR  
nEndPos = input.readLong(); J4=_w  
} 81%8{yn!$"  
input.close(); dx,=Rd5'  
} &ff&Y.q~  
catch(IOException e){e.printStackTrace ();} WhBpv(q}.  
catch(Exception e){e.printStackTrace ();} ^2odr \  
} #,(sAj  
O8U<{jgAG  
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private void processErrorCode(int nErrorCode) as+GbstN  
{ XI Jlc~2  
System.err.println("Error Code : " + nErrorCode); /Jf~25
F  
} ,&HR(jTo  
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zu2HH<E  
//停止文件下载 uE=$p)  
public void siteStop() m6
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{ ]v G{kAnH  
bStop = true; +KEkmXZ  
for(int i=0;i<nStartPos.length;i++) E^hHH?w+  
fileSplitterFetch.splitterStop(); k#}g,0@  
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!5}l&7:(MN  
} JIO$=+p  
} #(LfYw.P1V  
//负责部分文件的抓取 O;[9_[  
**FileSplitterFetch.java dz#5
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*/ ZiFooA  
package NetFox; JM.XH7k  
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import java.io.*; 2h {q h  
import java.net.*; E3/:.t  
9^F2$+T[:  
8iC:xcN3  
public class FileSplitterFetch extends Thread { 2WvN2"f3  
Ap\AP{S4  
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String sURL; //File URL  ,%
#  
long nStartPos; //File Snippet Start Position EA<}[4#jS  
long nEndPos; //File Snippet End Position |rRG=tG_'  
int nThreadID; //Thread's ID ]7AX%EG3  
boolean bDownOver = false; //Downing is over lz | 64J  
boolean bStop = false; //Stop identical }iBC@`mg(  
FileAccessI fileAccessI = null; //File Access interface _L.n,  
% 0:p)Z0  
7yI@"c#O  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ps:f=6m2  
{ P`1EPF  
this.sURL = sURL;
;P?q2jI  
this.nStartPos = nStart; Fr
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this.nEndPos = nEnd; 0m9ZQ O  
nThreadID = id; bzmr"/#D3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _'x
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} R@T6U:1  
+:jT=V"X  
;SKh  
public void run() s]B"qFA  
{ #6S75{rnW"  
while(nStartPos < nEndPos && !bStop) o5Rz%k#h  
{ 0>6DSQq~t(  
\[wCp*;1}  
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try{ 8_\W/I!7b  
URL url = new URL(sURL); cm>E[SHr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); K=u0nrG*  
httpConnection.setRequestProperty("User-Agent","NetFox"); m)?5}ZwAH  
String sProperty = "bytes="+nStartPos+"-"; 1ywU@].6J]  
httpConnection.setRequestProperty("RANGE",sProperty); 0WxCSL$#I  
Utility.log(sProperty); r@)A k  
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? S=W&  
InputStream input = httpConnection.getInputStream(); Sj 3oV  
//logResponseHead(httpConnection); i&+w _hD  
>N`6;gn*l  
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byte[] b = new byte[1024]; IvBGpT"(I  
int nRead; *8g<R  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]Nk!4"  
{ s'a=_cN  
nStartPos += fileAccessI.write(b,0,nRead); ;\)=f6N  
//if(nThreadID == 1) 3-wD^4)O,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %EbiMo ]3B  
} d}0qJoH4  
&y_? rH  
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Utility.log("Thread " + nThreadID + " is over!"); sroGER.  
bDownOver = true; ]= x 1`j  
//nPos = fileAccessI.write (b,0,nRead); q
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} Re:T9K'e  
catch(Exception e){e.printStackTrace ();} ?KN:r E  
} 0~E 6QhV:  
} DR+,Y2!_GT  
]YD(`42x  
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//打印回应的头信息 E)'8U
 
public void logResponseHead(HttpURLConnection con) o$bUY7_  
{ _3^y|_!  
for(int i=1;;i++) =d20Xa  
{ pz}mF D&[  
String header=con.getHeaderFieldKey(i); #+sF`qR,  
if(header!=null) 0'ZYO
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); mc@M,2@D  
Utility.log(header+" : "+con.getHeaderField(header)); 4Z%Y"PL(K  
else X
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break; /#q")4Mf  
} |+ 7f2C  
} Q)6va}2ai  
Kr3];(w{  
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public void splitterStop() B\<ydN  
{ ,w\ wQn>]K  
bStop = true; 6Dzs?P  
} LDX
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} ?eWJa  
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/* i!~>\r\6\  
**FileAccess.java 8 lS($@@{  
*//文件访问(定位，写) {rGYRn,  
package NetFox; T^)plWw  
import java.io.*; Xem| o&  
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public class FileAccessI implements Serializable{ XJFnih  
E%*AXkJ'dZ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 dq8+m(7k  
RandomAccessFile oSavedFile; ~/c5hyTx  
long nPos; ~zMKVM1Q.,  
@ M[Q$:  
O)5#Fcp(  
public FileAccessI() throws IOException ]gP8?s|  
{ UH40~LxIma  
this("",0); c^-YcGwa  
} xyV]?~7  
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DT? m/*  
public FileAccessI(String sName,long nPos) throws IOException hDtKnF  
{ wznn #j  
oSavedFile = new RandomAccessFile(sName,"rw"); =HPu{K$  
this.nPos = nPos; a/e\vwHLv  
oSavedFile.seek(nPos); ;eR{tH /4  
} (5(fd.m+_  
s`Vf+l0  
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public synchronized int write(byte[] b,int nStart,int nLen) "t+r+ipf])  
{ N9*UMVU  
int n = -1; YX `%A6  
try{ qhxC 5f4Z  
oSavedFile.write(b,nStart,nLen); 0WS|~?OR@  
n = nLen; BGpk&.J  
} uHrb:X!q  
catch(IOException e) @U7Dunu*f  
{ +E#PJ_H=F8  
e.printStackTrace (); z[biK|YL  
} $B ?? Ip?P  
Y UZKle  
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return n; lVT&+r~r  
} [D9
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} y*|L:!   
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jNqVdP]d\  
/* J(hA^;8:  
**SiteInfoBean.java dqwWfn1lt  
*/ iE+6UK  
package NetFox; yjv&4pIc1  
$P_x
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]W|RtdF3.N  
public class SiteInfoBean { K Dz]wNf  
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private String sSiteURL; //Site's URL p
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private String sFilePath; //Saved File's Path x!`KhTu`_A  
private String sFileName; //Saved File's Name ul$omKI$}  
private int nSplitter; //Count of Splited Downloading File #}j]XWy  
EFv4=OWB  
T8mY#^sW_  
public SiteInfoBean() @dl<-  
{//nSplitter的缺省值为5 \3: L Nt  
//default value of nSplitter is 5 XP4jZCt9  
this("","","",5); \
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} M0L-u  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y* rY~U#3  
{ ofl'G]/$+  
sSiteURL= sURL; 8}9Ob~on  
sFilePath = sPath; <\Vi,,  
sFileName = sName; 5C*?1& !  
this.nSplitter = nSpiltter; lf;~5/%wMG  
wU.'_SBfB  
M!-q}5';  
} =_uol8v  
%L28$c3p  
4^`PiRGt  
public String getSSiteURL() mUiOD$rO  
{ nc-Qz  
return sSiteURL; .dt#2a_5q  
} {q})kO  
<TL])@da  
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public void setSSiteURL(String value) Pb3EnNqYbM  
{ i>WOYI9  
sSiteURL = value; fHLFeSfH  
}
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\3L$I-]m  
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public String getSFilePath() ktU9LW~  
{ hJ<:-u+yk}  
return sFilePath; " S ?Km  
} &^AzIfX}Gw  
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Vn@A]Jx^  
public void setSFilePath(String value) Y=hPErw  
{ vY4WQbz(  
sFilePath = value; 3Gj(z:)b  
} N'I?fWN!;R  
bb*c+XN0  
*X%?3"WH8  
public String getSFileName() 3D{82*&  
{ [5x+aW%ql  
return sFileName; i:MlD5 F  
} EPQ&?[6  

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public void setSFileName(String value) E=$7ieW  
{ |G[
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sFileName = value; pHq{S;R2G  
} L~'^W/N  
z?8zFP  
['Hp?Q|k  
public int getNSplitter() ?IL! X-xx  
{ Dh*~U:6$g  
return nSplitter; u]ZqF 
*  
} }w;Q^EU  
B)_!F`9  
E|KLK4]  
public void setNSplitter(int nCount) BnY\FQ)K  
{ V5hp Y ]  
nSplitter = nCount; 95_[r$C  
} N:m@D][/sW  
} <|mE9u  
,e}mR>i=e  
*?EjYI  
/* fx8y`8}_  
**Utility.java gEcnn.(S  
*/ CD XB&%Sr  
package NetFox; -`<6=[QUO  
8Cf^$   
@h,h=X  
public class Utility {
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public Utility() F]dmc,Q  
{ UXcH";*9b  
>[A65q'  
Om&{4a\  
} dVY(V&p  
A>rWGo.{E  
//线程睡眠 EZgxSQaPH  
public static void sleep(int nSecond) Pf^Ly97  
{ O=4ceEmz  
try{ TWl(\<&+)  
Thread.sleep(nSecond); ]
%vGC^  
} .j'@K+<45  
catch(Exception e) Z<$E.##  
{ 8`R +y  
e.printStackTrace (); D}k-2RM2k  
} N,'[:{GOY  
} r7]?g~zb  
mjkw&2  
//日志 3Vb=6-|  
public static void log(String sMsg) LOyCx/n  
{ < e7<t9  
System.err.println(sMsg); s$2l"|h>B  
} LZZ:P
 
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ebl)6C  
public static void log(int sMsg) q.u[g0h;  
{ YU ]G5\UU  
System.err.println(sMsg); b7>,-O  
} [qjAq@@N#q  
} B6Wq/fl/  
aHVdClD2o  
hPEp0("  
/* JsWq._O{/  
**TestMethod.java W>t&N  
*/ 1DI"LIL  
package NetFox; R9|2&pfm(M  
3
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c:`` Y:  
public class TestMethod { B~'VDOG$Z  
yP1Y3Tga=  
~t.WwxY+  
public TestMethod() /I`bh  
{ ///xx/weblogic60b2_win.exe 'Z(MV&  
try{ @?^LxqAWA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %Mb( c+7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .5#tB*H  
SiteFileFetch fileFetch = new SiteFileFetch(bean); |R &3/bEr  
fileFetch.start(); uZ=UBir  
} g~$GE},,  
catch(Exception e){e.printStackTrace ();} @FnI?Rx  
7am/X.  
>TQBRA;'  
} GP7)m  
>TY5ZRB  
vS24;:f  
public static void main(String[] args) cA (e"N  
{ +|}K5q\  
new TestMethod(); #<PA- y  
} NP<F==,  
} HIWmh4o/.  
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