http断点续传简单实现（java)

/* .[2MPjg  
**SiteFileFetch.java :1Fm~'  
*/ Q=PaTh   
package NetFox; d'[aOH4}  
import java.io.*; }%k"qW<Y  
import java.net.*; <u2*(BM4  
'12|:t&7  
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public class SiteFileFetch extends Thread {  b1[U9  
i $I|JJJ  
/=e[(5X|O  
SiteInfoBean siteInfoBean = null; //文件信息Bean sWavxh8A  
long[] nStartPos; //开始位置 ziH2<@  
long[] nEndPos; //结束位置 k
}lx!Ck  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Z7.)[ ;  
long nFileLength; //文件长度 R@VO3zsW  
boolean bFirst = true; //是否第一次取文件 BLaXp0  
boolean bStop = false; //停止标志 'dU$QO  
File tmpFile; //文件下载的临时信息 RTY$oUqlZ  
DataOutputStream output; //输出到文件的输出流 o=`
9JKB~  
( ?/0$DB  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） TdQ^^{SRp  
public SiteFileFetch(SiteInfoBean bean) throws IOException r]HLO'<]  
{ !%s7I^f*  
siteInfoBean = bean; "apv)xdW  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); KG3*~G  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =JVRm 2#*  
if(tmpFile.exists ()) IB!Wrnj?  
{ 2WUBJ-qnuT  
bFirst = false; ^_+ks/  
read_nPos(); U1q$B32  
} +:'Po.{"  
else nr-
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{ )<^ ~${$U  
nStartPos = new long[bean.getNSplitter()]; ok6e=c '  
nEndPos = new long[bean.getNSplitter()]; :T{or-  
} 8dA
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} xrX("ili  
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public void run() ]@8=e'V  
{ hYWWvJ)S  
//获得文件长度 T=R
94  
//分割文件 X^.r@tT  
//实例FileSplitterFetch s lI)
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//启动FileSplitterFetch线程 &pba~X.u  
//等待子线程返回 2(c#m*Q!b  
try{ i@I%$!cB  
if(bFirst) ix#  
{ D$mrnm4d  
nFileLength = getFileSize();
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if(nFileLength == -1) H~~(v52wD  
{ yv:NH|,/y  
System.err.println("File Length is not known!"); @<6-uk3S  
} X_YD[  
else if(nFileLength == -2) V3+%KkN  
{ '~2v/[<`}  
System.err.println("File is not access!"); |1<Z3\+_/  
} ^CE:?>a$  
else *ap#*}r!Nk  
{ [`b{eLCFX]  
for(int i=0;i<nStartPos.length;i++) VuBp$H(U  
{ mPD'"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); uf>w*[m5  
} @'rO=(-b  
for(int i=0;i<nEndPos.length-1;i++) % (.PRRI  
{ *AA1e}R{B  
nEndPos = nStartPos[i+1]; /vV 0$vg  
} vOj$-A--qU  
nEndPos[nEndPos.length-1] = nFileLength; d{trO;%#f  
} LtU+w*Gj  
} wS^-o  
co@8w!W  
MmK\|CtV  
//启动子线程 TSk6Q'L\v  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 'oEmbk8Hg  
for(int i=0;i<nStartPos.length;i++) Cn<kl^!Q-  
{ l^"G\ZVI  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !INr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }*t~&l0  
nStartPos,nEndPos,i); I|5OCTu
 
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ={Hbx>p  
fileSplitterFetch.start(); Sce9R?II  
} yh)q96m-V=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o&O!Ur  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `2oi~^.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `WT7w']NT  
nEndPos = " + nFileLength); i*tj@5MY-  
// fileSplitterFetch[nPos.length-1].start(); QM]^@2rK2  
X<{m;T `  
&Xav$6+Z1J  
//等待子线程结束 Ll`apKr  
//int count = 0; $d=lDN  
//是否结束while循环 zW _'sC  
boolean breakWhile = false; YH>n{o;- ?  
tc',c},h~,  
k);!H+  
while(!bStop) 3YRzBf:h  
{ r__M1 !3  
write_nPos(); 21[F%,{.),  
Utility.sleep(500); IW#(ICeb  
breakWhile = true; #n"/9%35f`  
?xet:#R'  
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for(int i=0;i<nStartPos.length;i++) jZ;T&s  
{ t]ZSo
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if(!fileSplitterFetch.bDownOver) !jbjrzv9  
{ T,fz/5w  
breakWhile = false; z|2liQrf+  
break; KOQTvJ_#  
} Bz{ g4!ku  
} /b|sv$BN  
if(breakWhile) xpk|?/6  
break; {;zPW!G  
4
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v+G:,Tc"  
//count++; ;D1IhDC  
//if(count>4) +\%zy=  
// siteStop(); f/x "yUq  
} 1
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SMyg=B\x?7  
1dcy+ !>  
System.err.println("文件下载结束！"); MlZ`g,{  
} cOQy|v`KD,  
catch(Exception e){e.printStackTrace ();} 9?8`"v  
} 3^Zi/r  
-,dQ&Qf?  
D|o@(V  
//获得文件长度 %8Z,t+'  
public long getFileSize() qHCs{ u  
{ X3[!xMij  
int nFileLength = -1; :dzU]pk%0  
try{ +0 MKh  
URL url = new URL(siteInfoBean.getSSiteURL()); Sx2j~(pOr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); IoA;q)  
httpConnection.setRequestProperty("User-Agent","NetFox"); B
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YYHm0pc  
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int responseCode=httpConnection.getResponseCode(); Q\76jD`m\  
if(responseCode>=400) iIFQRnpu;3  
{ <B`V  
processErrorCode(responseCode); 4lA+V,#  
return -2; //-2 represent access is error K^Ht$04  
} z"3c+?2  
(zBQ^97]  
={^#E?  
String sHeader; oK6lCGM5  
tOw 0(-:iq  
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for(int i=1;;i++) G$ FBx  
{ ~<aB-.d  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); C)
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//Utility.log(in.readLine()); .K
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sHeader=httpConnection.getHeaderFieldKey(i); :!$z1u8R  
if(sHeader!=null) ">3@<f>  
{ +0Gep}&z.  
if(sHeader.equals("Content-Length")) Kcl$|T  
{ #A;Z4jK  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); YkX=n{^  
break; zwtsw[.  
} ]B4mm__  
} ~-d.3A$u  
else b U NYTF{  
break; rLxX^[Fp3  
} _GqE'VX  
} 1!3kAcBP  
catch(IOException e){e.printStackTrace ();} +`8)U3u0  
catch(Exception e){e.printStackTrace ();} "N]o5d  
wVDB?gy%#  
: qRT9n$  
Utility.log(nFileLength); P~e$iBH'  
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return nFileLength; 09Y?!,  
} |@.<}/  
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s.'\&B[  
//保存下载信息（文件指针位置） p;$9W+H0  
private void write_nPos() G:`Jrh  
{ D}sGBsOW  
try{ zF&UdS3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5#.\pR{Gd  
output.writeInt(nStartPos.length); vc#oALc&  
for(int i=0;i<nStartPos.length;i++) vv/,Rgv  
{ ^z^e*<{WEl  
// output.writeLong(nPos); I!gj;a?R  
output.writeLong(fileSplitterFetch.nStartPos); 9 w1ONw8v  
output.writeLong(fileSplitterFetch.nEndPos); ?bAFYF0!I  
} gqRTv_;  
output.close(); % Au$E&sj  
} aa8Qslm  
catch(IOException e){e.printStackTrace ();} bK\WdG\;  
catch(Exception e){e.printStackTrace ();} b6&NzUt34V  
} ?4e6w  
#Hi]&)p_  
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//读取保存的下载信息（文件指针位置） 3^>a TU<Z  
private void read_nPos() od*Z$Hb>'  
{ vN:[  
try{ )C]&ui~1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *Ne&SXg  
int nCount = input.readInt(); c8tC3CrKp=  
nStartPos = new long[nCount]; h;qy5KS  
nEndPos = new long[nCount]; ^alZ\!B8  
for(int i=0;i<nStartPos.length;i++) R2THL  
{ Wx$q:$h@q  
nStartPos = input.readLong(); FJ8@b  
nEndPos = input.readLong(); BK9x`Oo2  
} qO{ ZZ*  
input.close(); 2,V+?'^j  
} P
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catch(IOException e){e.printStackTrace ();} 1Dp@n  
catch(Exception e){e.printStackTrace ();} _G #"B{7  
} wI@I(r~g  
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private void processErrorCode(int nErrorCode) /I'u/{KB  
{ 9+ l3$  
System.err.println("Error Code : " + nErrorCode); e~.?:7t  
} k
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)kKmgtj  
o Xi}@  
//停止文件下载 Du:p!nO  
public void siteStop() YQV?S  
{ W^.-C  
bStop = true; s%[GQQ-N  
for(int i=0;i<nStartPos.length;i++) UXPegK!  
fileSplitterFetch.splitterStop(); Wk#h,p3  
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} ttFY _F~S  
}
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//负责部分文件的抓取 a`b zFu{  
**FileSplitterFetch.java RE $3| z  
*/ |
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package NetFox; %=9yzIjbAt  
5%?b5(mnD  
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import java.io.*; UlNfI}#X  
import java.net.*; 1D
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o.3YM.B#  
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public class FileSplitterFetch extends Thread { XL PpxG  
!Nl.Vb  
M*|VLOo=v  
String sURL; //File URL }"?nU4q;S  
long nStartPos; //File Snippet Start Position Zxc7nLKF~  
long nEndPos; //File Snippet End Position (s$u_aq77  
int nThreadID; //Thread's ID ? x"HX|n  
boolean bDownOver = false; //Downing is over !@<@QG
-  
boolean bStop = false; //Stop identical [Z5[~gP3  
FileAccessI fileAccessI = null; //File Access interface -9>LvLU  
Np<&#s[dQ  
X')Zm+  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException mPfUJ#rS  
{ !Wixs]od   
this.sURL = sURL; /pN'K5@  
this.nStartPos = nStart; Cb{A:\>Q{  
this.nEndPos = nEnd; $HBT%g@UN  
nThreadID = id; juMxl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 tpa^k  
} hB7pR"P  
^0~c7`k`V  
!/6\m!e|1R  
public void run() ZEj!jWP2m  
{ [.j]V-61  
while(nStartPos < nEndPos && !bStop) 0SMQDs5j  
{ w3=)S\  
FL`1yD^2  

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try{ w}j6.r  
URL url = new URL(sURL); $89ea*k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xaWGa1V'z  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,rZn`9  
String sProperty = "bytes="+nStartPos+"-"; hqs$yb  
httpConnection.setRequestProperty("RANGE",sProperty); V~T`&  
Utility.log(sProperty); T)(e!Xz  
"*w)puD  
j,=*WG  
InputStream input = httpConnection.getInputStream(); ?"
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//logResponseHead(httpConnection); F_nZvv[H?  
t=Z&eKDC  
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byte[] b = new byte[1024]; fW.GNX8
 
int nRead; ,@Fgr(?'`>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9fP) Fwih  
{ CF|moc:;  
nStartPos += fileAccessI.write(b,0,nRead); m<4s*q0\i  
//if(nThreadID == 1) V$dJmKg  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G@!_ZM8h  
} g\o{}Q%X  
.-SF$U_P*a  
N7*CP|?E  
Utility.log("Thread " + nThreadID + " is over!"); ]*2EK9<  
bDownOver = true; L\b]k,Ksf  
//nPos = fileAccessI.write (b,0,nRead); 3@^>#U   
} -G],H)M  
catch(Exception e){e.printStackTrace ();} gX@nPZjg  
} psIkG0 &  
} Hz}+SAZ  
&Y,Q>bu  
-F"d0a,  
//打印回应的头信息 / R_ u\?k(  
public void logResponseHead(HttpURLConnection con) {)B9Z I{+A  
{ CKv&Re  
for(int i=1;;i++) F!7f_m0=  
{ g7xbyBo7  
String header=con.getHeaderFieldKey(i); +/y{^}b/  
if(header!=null) xLx"*jyL  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >|a\>UgC  
Utility.log(header+" : "+con.getHeaderField(header)); atY*8I|  
else K??1,I  
break; iV?` i  
} J`w]}GlH  
} T3PX gL)o  
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public void splitterStop() k)`$%[K8  
{ !0I
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bStop = true; HEBqv+bG  
} Z)m
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} pC*BA<?Rg  
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/* tC&fAE:S  
**FileAccess.java U;\S(s}  
*//文件访问(定位，写) j]pohxn$5  
package NetFox; .Y!;xB/  
import java.io.*; $ZQ"({<w<g  
F9MR5O"  
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public class FileAccessI implements Serializable{ 4P|$LkI  
G%a] j  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 XVw-G }5  
RandomAccessFile oSavedFile; pd d|n2q  
long nPos; 1Gsw-a;a  
!:(C"}5wM  
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public FileAccessI() throws IOException ?VB#GJ0M9  
{ eGLO!DdxZ  
this("",0); U,PZMz`2j  
} k, f)2<  
<EtUnj:qK8  
 ]nUR;8  
public FileAccessI(String sName,long nPos) throws IOException RI-A"cc6A  
{ &vCeLh:s  
oSavedFile = new RandomAccessFile(sName,"rw"); "Y7+{  
this.nPos = nPos; 4E
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oSavedFile.seek(nPos); C\ vC?(n  
}
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%JQ~!3  
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public synchronized int write(byte[] b,int nStart,int nLen) R:"+ #Sq  
{ Z!=L   
int n = -1; .(|+oHg<  
try{ BDy5J2<<7l  
oSavedFile.write(b,nStart,nLen); tQrS3Hz'nA  
n = nLen; .`,F  
} Uo2+:p  
catch(IOException e) Vvyj  
{ )u;JwFstX  
e.printStackTrace (); .d~\Ysve  
} )GVBE%!WEd  
uFZ~  
~Rs#|JWB2V  
return n; abBO93f^  
} @lS==O-`f  
# :#M{1I  
}f#_4ACaD  
} FEF"\O|Q  
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+{.780|  
/* }X]\VSF{  
**SiteInfoBean.java 1Dq<{;rWb  
*/ bhD ~4Rz  
package NetFox; Ry z?v<)h  
o@9+mM"B)  
w?*z^y@  
public class SiteInfoBean { w$j{Hp6m  
DzC Df@TB"  

6\4Z\82  
private String sSiteURL; //Site's URL l&L,7BX  
private String sFilePath; //Saved File's Path mG2VZ>  
private String sFileName; //Saved File's Name N5?IpE  
private int nSplitter; //Count of Splited Downloading File llq*T"
7  
,}0$Tv\1  
]]TqP{H  
public SiteInfoBean() edijfhn  
{//nSplitter的缺省值为5 J!hFN]M<<  
//default value of nSplitter is 5 TQf L%JT  
this("","","",5); BC! 6O/
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} ZQAO"huk]  
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M+poB+K.  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) R)oB!$k  
{ %
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sSiteURL= sURL; fW(/Loh  
sFilePath = sPath; *KJB>W%@uM  
sFileName = sName; E9+HS  
this.nSplitter = nSpiltter; bb;(gK;F  
bO3GVc+S  
dU]/$7  
} H(|AH;?ou  
F_=1;,K%  
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public String getSSiteURL() 6Ps.
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{ $.rzc]s  
return sSiteURL; R,t$"bOd  
} S2K#[mDG  
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public void setSSiteURL(String value) +C+<BzR~A.  
{ "R[l ZJ@  
sSiteURL = value; E]I$}>k  
} gCuAF$o  
?Go!j?#a  
aD9q^EoEs  
public String getSFilePath() gEwd &J  
{ *geN[[  
return sFilePath; >&U@f  
} ST Z]8cw  
m#e*c[*G  
V`#.7uUP  
public void setSFilePath(String value) C\}
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{ lp
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sFilePath = value; y('k`>C  
} RWKH%C[Yd  
eC! #CK  
-*B`]  
public String getSFileName() ~#PLAP3-  
{ Ez+Z[*C  
return sFileName; l_{8+\`!  
} epg#HNP7^Y  
J !HjeZ  
g(Yb^'X/  
public void setSFileName(String value) *?t%0){  
{ A"uULfnk  
sFileName = value; pOT7;-#n  
} 'cBBt  
$s-Y%gc  
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public int getNSplitter() Z=?aEU$7  
{ S`!-Cal`n  
return nSplitter; -!e7L>w  
} s?rBE.g@}  
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i7*EbaYzUO  
public void setNSplitter(int nCount) 4J0Rvod_  
{ LWnR?Qve<  
nSplitter = nCount; VT%:zf  
} k;ZxY"^  
} 4x;_AN  
ABh&X+YD  
!w39FfU{  
/* p{D4"Qn+P9  
**Utility.java ;# uZhd  
*/ 5!X1G8h)uy  
package NetFox; O|kOI?f  
9?<{_'  
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public class Utility { fCWGAO2  
)h{ ]k=  
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public Utility() 5PT5#[  
{ MGJ.,tK1  
k8AW6oO/i  
n'1'!J;
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} PcT?<HU  
%]2,&  
//线程睡眠 fHRMu:q  
public static void sleep(int nSecond) {)8>jxQN  
{ Az;t"  
try{ @p6<Lw_E  
Thread.sleep(nSecond); b^0}}12  
} Jl3g{a  
catch(Exception e) 'cix`l|^  
{ kF"@Ngv.  
e.printStackTrace (); n+;6=1d7ZW  
} 'Ft0Ry<OL  
} vw,rF`LjZ  
p Z: F:  
//日志 TS2ZF{m  
public static void log(String sMsg) W2FD+ wt  
{ _tTNG2  
System.err.println(sMsg); gKYfQ+  
} $5
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E_e6^Sk5B(  
?i
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public static void log(int sMsg) .Z:zZ_Ev  
{ l vMlL5t  
System.err.println(sMsg); y*pUlts<  
} w-wV3Q6X  
} :L44]K5FL  
mpPdG  
u_(VEfs4  
/* J &pO%Q=b  
**TestMethod.java d)4 m6  
*/ Qham^  
package NetFox; 26&'X+n&  
}by;F
9&B  
u/cg|]x&T  
public class TestMethod { Q8!)!r%  
)OiT{-m  
35E_W>n  
public TestMethod() x=ul&|^7D  
{ ///xx/weblogic60b2_win.exe qlL`jWJ  
try{ mEw ~yOW]M  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); X.hm s?]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <B9C*M"4%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *s9C!wYMZ  
fileFetch.start(); CC#;c1t  
} d ,4]VE  
catch(Exception e){e.printStackTrace ();} &?mD$Eo  
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?c[*:N(  
} o.0ci+z@  
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public static void main(String[] args) {&jb5-*f  
{ ne4Q#P  
new TestMethod(); 'nXl>  
} gw,UQbnu  
} ma"3qGy  
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