http断点续传简单实现（java)

/* r~f*aD  
**SiteFileFetch.java VF#2I%R*  
*/ 2@7f^be  
package NetFox; C8ss6+k&  
import java.io.*; rl:6N*kK  
import java.net.*; {#?$p i[  
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public class SiteFileFetch extends Thread { }ACWSkWK  
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*[XVkt`H  
SiteInfoBean siteInfoBean = null; //文件信息Bean ad <z+a  
long[] nStartPos; //开始位置 aTi2=HL=S  
long[] nEndPos; //结束位置 T2EQQFs  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :A
2{  
long nFileLength; //文件长度 -@*[   
boolean bFirst = true; //是否第一次取文件 qH1k  
boolean bStop = false; //停止标志 |:qaF  
File tmpFile; //文件下载的临时信息 AQ}(v,DOb  
DataOutputStream output; //输出到文件的输出流 R
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 7E0L-E=.  
public SiteFileFetch(SiteInfoBean bean) throws IOException +-%&,>R  
{ #:q$sKQ_$  
siteInfoBean = bean; <H; z4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); rN$U%\.I  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); z2.9l?"rfQ  
if(tmpFile.exists ()) &-5`Oln  
{ +, IMN)?;z  
bFirst = false; b\Wlpb=QZ  
read_nPos(); +ConK>;  
} *
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else wP|Amn+;  
{ NE~R&ym9  
nStartPos = new long[bean.getNSplitter()]; h4iz(*  
nEndPos = new long[bean.getNSplitter()]; 0c-.h  
} E*B6k!:  
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} _VjfjA<c8  
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public void run() V(6*wQ`&  
{ s^&Oh*SP*  
//获得文件长度 Wx8oTN  
//分割文件 :cE6-Fv  
//实例FileSplitterFetch n%Rl$  
//启动FileSplitterFetch线程  S6d&w6  
//等待子线程返回 mm1fG4 *%  
try{ .="/n8B  
if(bFirst) qH=<8Iu  
{ bb4
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nFileLength = getFileSize(); 39yp1  
if(nFileLength == -1) 2 -C*RHRx  
{ mVs<XnA47  
System.err.println("File Length is not known!"); o9XT_!Cwg  
} W5SCm(QS5  
else if(nFileLength == -2) K*/X{3J;  
{ v'e5j``=  
System.err.println("File is not access!"); qlU"v)Mx  
} m>:zwz< ;  
else f(*ygI  
{ 'JpCS  
for(int i=0;i<nStartPos.length;i++) j3Yz=bsQ{c  
{ J1\H^gyW)  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); US'rhSV  
} }\?]uNH  
for(int i=0;i<nEndPos.length-1;i++) tb1w 6jaU  
{ 'V`Hp$r  
nEndPos = nStartPos[i+1]; 3 q^^Os  
} $&ZN%o3  
nEndPos[nEndPos.length-1] = nFileLength; xm*6I  
} `Ei:Z%@7C  
} xgQ&'&7l  
isR)^fI|  
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//启动子线程 cYx.<b JH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; z#u<]] 5  
for(int i=0;i<nStartPos.length;i++) (X?et &  
{ Z1Pdnc7S[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A>Y#-e;<d  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), \\(3gB.Gd  
nStartPos,nEndPos,i); &<Iz?AVr  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *1b1phh0/  
fileSplitterFetch.start(); &57s//PrX  
} A>B_~=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mhi^zHpa  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ZD#{h J-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >0AVs6&;v  
nEndPos = " + nFileLength); TD^w|U.  
// fileSplitterFetch[nPos.length-1].start(); qgkC
)
  
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//等待子线程结束
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//int count = 0; i7jI(VvB^  
//是否结束while循环 8h$f6JE  
boolean breakWhile = false; 3cB=9Y{<  
%^LwLyoVM  
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while(!bStop) =g^k$ Rc  
{ }pOJM&I  
write_nPos(); v[!ZRwk4w3  
Utility.sleep(500); |S.;']t+  
breakWhile = true; +<$b6^>!$  
)mh,F#"L  
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for(int i=0;i<nStartPos.length;i++) t_NnQ4)
=  
{ K0-AP $  
if(!fileSplitterFetch.bDownOver) P0O=veCf  
{ u0i;vO)MNt  
breakWhile = false; .3:s4=(f  
break; "3e1 7dsY  
} R$M>[Kjn  
} ~Bls
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if(breakWhile) ",>,t_J  
break; $e/[!3CASP  
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//count++; a8v9j3.  
//if(count>4) Q)%a2s;  
// siteStop(); k35E,?T  
} _2wH4^Vb  
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}U_z XuUz  
System.err.println("文件下载结束！"); 6[S-%|f  
} vfpK|=[7o  
catch(Exception e){e.printStackTrace ();} rw%1>]os  
} bTJ l  
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]~t4E'y)z  
//获得文件长度 ;T\'|[bY   
public long getFileSize() )I(2t 6i  
{ `HV~.C  
int nFileLength = -1; )Nkf'&  
try{ zTb,h  
URL url = new URL(siteInfoBean.getSSiteURL()); xk@fBa }  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &+Yoob]P  
httpConnection.setRequestProperty("User-Agent","NetFox"); _6Qb 3tl  
4#Id0['  
]^BgSC  
int responseCode=httpConnection.getResponseCode(); "e@?^J)  
if(responseCode>=400) `R@b`3*%v  
{ ,); -v4$  
processErrorCode(responseCode); l2 mO{'|C  
return -2; //-2 represent access is error R~!md  
} vq-#%o  
[
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String sHeader; Ew>lk9La(  
T
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for(int i=1;;i++) I`4k5KB;  
{ PCZ%<>v  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); / &#b*46  
//Utility.log(in.readLine()); ~%d*#Yxq  
sHeader=httpConnection.getHeaderFieldKey(i); p$_X\,F  
if(sHeader!=null) " 'TEBkj|u  
{ =L9;8THY  
if(sHeader.equals("Content-Length")) (MnK \^Y  
{ c(r8 F[4w  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); tr-muhuK  
break; vuO~
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} D9;s%  
} gSt'<v  
else B0$.oavC  
break; FC }r~syqA  
} a n,$Z,G#K  
} J8#3?Lp  
catch(IOException e){e.printStackTrace ();} xY$@^(Q\  
catch(Exception e){e.printStackTrace ();} R~H+.Vh  
? H7?>ZE  
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Utility.log(nFileLength); W}rLHAaDh  
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return nFileLength; A_}6J,*u  
} xF])NZy|  
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h7cE"m  
//保存下载信息（文件指针位置） ;b;Bl:%?  
private void write_nPos() KxUO=v<u  
{ `|f1^C^  
try{ IXof-I%8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S7f"\[Aw  
output.writeInt(nStartPos.length); tde&w=ec  
for(int i=0;i<nStartPos.length;i++) u]jvXPE6  
{ \3 M%vJ  
// output.writeLong(nPos); 
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output.writeLong(fileSplitterFetch.nStartPos); m`6=6(_p  
output.writeLong(fileSplitterFetch.nEndPos); w*krPaT3  
} mWX{I2  
output.close(); MoMxKmI  
} t2RL|$>F1  
catch(IOException e){e.printStackTrace ();} EVW\Z 2N.  
catch(Exception e){e.printStackTrace ();} %WAaoR&u  
} dj5@9X  
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`C>De4nT@  
//读取保存的下载信息（文件指针位置） -AZ\u\xCB  
private void read_nPos() <(W:Q3?s  
{ (%SKTM  
try{ c%5Suu(J6  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Gc2:^FVlh  
int nCount = input.readInt(); C1po]Ott*  
nStartPos = new long[nCount]; `=19iAp.  
nEndPos = new long[nCount]; OXD*ZKi8  
for(int i=0;i<nStartPos.length;i++) $_Q]3"U  
{ 3%YDsd vQx  
nStartPos = input.readLong(); 
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nEndPos = input.readLong(); Ob@HzXH  
} eoxEnCU  
input.close(); wrAcVR  
} h4N&Ybfo  
catch(IOException e){e.printStackTrace ();} JGQ)/(  
catch(Exception e){e.printStackTrace ();} Mc/= Fs  
} ,| ~Pa  
CM4#Nn=i~  
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private void processErrorCode(int nErrorCode) Hl=M{)q@   
{ .RN2os{  
System.err.println("Error Code : " + nErrorCode); uy8mhB+]  
} R/Te;z  
?$~5ti#\  
DH!_UV  
//停止文件下载 qv)%)n  
public void siteStop() l,:>B-FV  
{ |G(I,EPag  
bStop = true; *nlDN4Y[  
for(int i=0;i<nStartPos.length;i++) {)PgN  
fileSplitterFetch.splitterStop(); DTz)qHd#X  
i^}ib RQbN  
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}  wkKSL  
} 51Q~/  
//负责部分文件的抓取 vBYk"a6SD  
**FileSplitterFetch.java g]jCR*]  
*/ g<^-[w4/  
package NetFox; ->`R[k  
,$bK)|pGV  
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import java.io.*; SY$%)(c8kL  
import java.net.*; %OJq(}  
)M_|r2dDq3  
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public class FileSplitterFetch extends Thread { :ioD*k  
E{]PfUfFY  
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String sURL; //File URL 5E0dX3-  
long nStartPos; //File Snippet Start Position x\5v^$  
long nEndPos; //File Snippet End Position %s ">:  
int nThreadID; //Thread's ID :|\)=4  
boolean bDownOver = false; //Downing is over #PQhgli  
boolean bStop = false; //Stop identical ky I~  
FileAccessI fileAccessI = null; //File Access interface >DoP2]  
_[,7DA.qc  
xP$\ }  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1ZO/R%[  
{ RuWu#tk  
this.sURL = sURL; Mi047-% (  
this.nStartPos = nStart; nTCwLnX(O  
this.nEndPos = nEnd; ?JMy  
nThreadID = id; Ny G?^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $PFE>=nM  
} M?QX'fia  
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public void run() `u$lSGl  
{ Yz? 8n  
while(nStartPos < nEndPos && !bStop) FY"csZ  
{ TV~S#yg+H  
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0N):8`dY  
try{ s3y"y_u  
URL url = new URL(sURL); tf6 Zz[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =6gi4!hE  
httpConnection.setRequestProperty("User-Agent","NetFox"); |Q$9I#rv  
String sProperty = "bytes="+nStartPos+"-"; f7I!o,/  
httpConnection.setRequestProperty("RANGE",sProperty); -;iCe7|Twf  
Utility.log(sProperty); s=hao4v7z  
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InputStream input = httpConnection.getInputStream(); tgC)vZ&a  
//logResponseHead(httpConnection); 9{8xMM-  
3]h*6V1
$  
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byte[] b = new byte[1024]; qv3% v3\4  
int nRead; w]O,xO  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) n a+P|'6  
{ }s:~E2?In  
nStartPos += fileAccessI.write(b,0,nRead); >\[|c  
//if(nThreadID == 1) PLRMW2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }-~LXL%!3  
} 3u[5T|D'  

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W|\$}@>  
Utility.log("Thread " + nThreadID + " is over!"); naVbcY  
bDownOver = true; 3|=L1Pw#  
//nPos = fileAccessI.write (b,0,nRead); c+501's  
} i!yE#z
ew  
catch(Exception e){e.printStackTrace ();} =)nJ'}x  
} .qs5xGg#9  
} $^`@lyr  
P.- `[  
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//打印回应的头信息 +!$]a^3l  
public void logResponseHead(HttpURLConnection con) "~L$oji  
{ :*MR$Jf  
for(int i=1;;i++) >1hhz  
{ Wv]ODEd  
String header=con.getHeaderFieldKey(i); 5IfC8drAs  
if(header!=null) zoZ10?ojC  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); UdcrX`^.  
Utility.log(header+" : "+con.getHeaderField(header)); ##nC@h@  
else yaYJmhG  
break; xc,Wm/[  
} J$i.^|hE/  
} GezMqt;2  
J=b'b%  
R)6"P?h._4  
public void splitterStop() ]E^)d|_  
{ yaPx=^&  
bStop = true; vrIWw?/z?  
} ;Q0H7)t:  
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} }z5u^_-m  
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8=OpX,t(  
/* rUZ09>nDy  
**FileAccess.java +h8`8k'}-2  
*//文件访问(定位，写) !Y10UmMu  
package NetFox; ]Rj?OSok  
import java.io.*; .yB{+  
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w9675D+  
public class FileAccessI implements Serializable{ V/BU(`~i  
?{\h`+A  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }WHq?  
RandomAccessFile oSavedFile; iw{^nSD  
long nPos; Bo8NY!  
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eIQ@){lJ-]  
public FileAccessI() throws IOException eU\XAN#@  
{ tgY/8&$M  
this("",0); {RI)I  
} .mplML0oW  
u{S"NEc  
"-S@R=bi  
public FileAccessI(String sName,long nPos) throws IOException >65\  
{ 9# #(B  
oSavedFile = new RandomAccessFile(sName,"rw"); ij?Ww'p9>  
this.nPos = nPos; T\"-q4+=C  
oSavedFile.seek(nPos); (wf3HEb_  
} j<
)`|?@e(  
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*!ecb1U5  
public synchronized int write(byte[] b,int nStart,int nLen) ZFs xsg^r  
{ Z9eP(ip  
int n = -1; 1Cw HGO  
try{ xqfIm%9i}  
oSavedFile.write(b,nStart,nLen); ?_eHvw  
n = nLen; kW=!RX[&  
} KbMan~Pb6  
catch(IOException e) gt\kTn."  
{ g([M hf#  
e.printStackTrace (); AF>t{rw=/  
} KW/LyiP#  
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return n; 4hzdc] a  
} e m  
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} yW&ka3j
\  
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/* ,c&gw tdl  
**SiteInfoBean.java ^I)+u>fJ  
*/ ij1YV2v  
package NetFox; ]n3!%0]\  
28vQ  
k U0.:Gcc  
public class SiteInfoBean { q
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wo;OkJKF  
+.Xi7x+#O  
private String sSiteURL; //Site's URL C[5dhFZ  
private String sFilePath; //Saved File's Path ^PUB~P/  
private String sFileName; //Saved File's Name OY2u,LF9H  
private int nSplitter; //Count of Splited Downloading File ]^,!;do  
"C
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@9R78Zra  
public SiteInfoBean() [s{[ .0P]+  
{//nSplitter的缺省值为5 'V&Tlw|  
//default value of nSplitter is 5 /f
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this("","","",5); zO@>)@~  
} RT${7=  
~/XDA:nfL:  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]B$J8.{q0  
{ a ,"   
sSiteURL= sURL; RhC|x,E  
sFilePath = sPath; `3`.usw  
sFileName = sName; 7C R6ew~  
this.nSplitter = nSpiltter; 1jO%\uR/  
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} *F!1xyg  
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public String getSSiteURL() %0 i)l|  
{ /4@ [^}x  
return sSiteURL; z:Z-2WV2o  
} SlwQ_F"4L  
.(3ec/i4CF  
4c[/%e:\-  
public void setSSiteURL(String value) Y6Ux*vhK  
{ (4Nj3x o  
sSiteURL = value; {e q378d  
} 9M5W4&  
R_\o`v5  
.rS. >d^n  
public String getSFilePath() r=~K#:66  
{ bwj{5-FU  
return sFilePath; (.X)=  
} 1b86@f  
aOS,%J^?  
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public void setSFilePath(String value) klH?
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{ K?r  
sFilePath = value; E@yo/S  
} j=Izwt>   
+k~0&lZi  
bE{

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public String getSFileName() T]nAz<l),  
{ >239SyC-,  
return sFileName; boHbiE  
} u0A$}r$L  
2dcvB]T!  
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public void setSFileName(String value) ?5/7 @V  
{ /sj*@HF=  
sFileName = value; Cs y,3XG  
} IN.g  
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?
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public int getNSplitter() *8po0s  
{ f*xr0l  
return nSplitter; :0QDV~bs  
} T\g+w\N  
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3u&,3:  
public void setNSplitter(int nCount) GC'e  
{ ir"t@"Y;o  
nSplitter = nCount; =5Nh}o(l?  
} O ;[Mi  
} GM?s8yZ<  
O"Nr$bS(Y  
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/* k!}(a0h  
**Utility.java 8A.7q  
*/ M=lU`Sm  
package NetFox; .a7RGT3]m  

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public class Utility { 8?Ju\W  
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public Utility() b9m`y*My  
{ d9BFeq8  
o-7{\%+M  
yNowhh
 
} p6K
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?|+e*{4k  
//线程睡眠 2[HPU M2>  
public static void sleep(int nSecond) GK!@|Kk8q7  
{ 6<$.Z-,  
try{ oBo*<6  
Thread.sleep(nSecond); {it}\[3  
} tx~,7TMS/  
catch(Exception e) ~!qnKM>[  
{ NjpWK;L  
e.printStackTrace (); u[Kz^ga<  
} vdC0tax  
} [l3\0
e6-/  
B^r?N-Z A  
//日志 ;?tH8jf>  
public static void log(String sMsg) K) fKL   
{ @j_o CDS  
System.err.println(sMsg); {+=hYB|&  
} P.C?/7$7Z+  
|Z{#DOT  
I;%1xdPt  
public static void log(int sMsg) \X _}\_c,d  
{ _uLpU4# ?  
System.err.println(sMsg); BDvkY  
} PA ?2K4  
} <%Nf"p{K  
t(6]j#5   
}DS%?6}Sy  
/* $qz{L~ <  
**TestMethod.java iD G&Muc  
*/ 't&1y6Uu  
package NetFox; \t&!
&R#  
TB* t^E  
k6&~)7 -f  
public class TestMethod { Ux*xz|^  
]vvA]e  
Sx'oa$J  
public TestMethod() 7@\.()  
{ ///xx/weblogic60b2_win.exe "Zh,;)hS  
try{ xb3G,F  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _ia&|#n  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O- QT+]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^tGAJ_b79  
fileFetch.start(); o>C,Db~L/  
} L6PgWc;m  
catch(Exception e){e.printStackTrace ();} m~AAO{\:b  
V [g^R*b  
j8p<HE51  
} k>mXh{(  
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j \jMN*dmV  
public static void main(String[] args) hmGlGc,lf  
{ Ye&/O<G'V  
new TestMethod(); Dg.~"h5mT  
}  x _>1x#  
} U&1O  
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