http断点续传简单实现（java)

/* Lm#d.AD)  
**SiteFileFetch.java 4V8wB}y7e  
*/ pr(\?\a  
package NetFox; taaAwTtk?A  
import java.io.*; DU8LU*q'  
import java.net.*; ':4pH#E  
*`T&Dlt'8  
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public class SiteFileFetch extends Thread { 7+4"+C
A  
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sb.SpF>   
SiteInfoBean siteInfoBean = null; //文件信息Bean |>GIPfVT  
long[] nStartPos; //开始位置 ^#se4qQ  
long[] nEndPos; //结束位置 -74T C  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >/bK?yT<  
long nFileLength; //文件长度 DjvgKy=Jr_  
boolean bFirst = true; //是否第一次取文件 0EXNq*=EE  
boolean bStop = false; //停止标志 y/eX(l<{  
File tmpFile; //文件下载的临时信息 Un{ln*AR\  
DataOutputStream output; //输出到文件的输出流 :j4 [_9\  
uF"`y&go  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） *!@x<Hf<  
public SiteFileFetch(SiteInfoBean bean) throws IOException tC-KW~&  
{ [HDO^6U  
siteInfoBean = bean; %tQ{Hf~  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); >+8I =S  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); r0 C6Ww7u  
if(tmpFile.exists ()) A"iD4Q  
{ Q@VnJ,  
bFirst = false; a@ }r[0O  
read_nPos(); >irT|VTf  
} j],.`Y  
else tta0sJ8i  
{ ] Nipo'N;  
nStartPos = new long[bean.getNSplitter()]; aZ`agsofk  
nEndPos = new long[bean.getNSplitter()]; ;@~*z4U  
} I]1Hi?A2  
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} ?<^AXLiKV  
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public void run() X.9MOdG70  
{ de{YgN  
//获得文件长度 tN> B$sv  
//分割文件 ER1mA:8>E  
//实例FileSplitterFetch Q.dy $`\  
//启动FileSplitterFetch线程 =2)t1 H  
//等待子线程返回 s/H"Ab  
try{ WVK-dBU  
if(bFirst) chzR4"WZFt  
{ }h h^U^ia  
nFileLength = getFileSize(); [=3tAPpzK  
if(nFileLength == -1) rss.F3dK  
{ 1t=X: ]0j  
System.err.println("File Length is not known!"); aZGDtzNG5h  
} ,GP4I3D  
else if(nFileLength == -2) f<p4Pkv  
{ _x1[$A,GuB  
System.err.println("File is not access!"); Al=? j#J6p  
} ,!u@
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else )Hm[j)YI  
{ X`QW(rq  
for(int i=0;i<nStartPos.length;i++) NVWeJ+w  
{ ~
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); vD9D:vK  
} 05I39/T%  
for(int i=0;i<nEndPos.length-1;i++) 2BA9T nxC  
{ - :z5m+  
nEndPos = nStartPos[i+1]; aW-o=l@;  
} EFt`<qwj  
nEndPos[nEndPos.length-1] = nFileLength; f<altz_\q  
} rtmt3  
} k&iScMgCTH  
^|i\d\  
h21(K}  
//启动子线程 kDl4t]j  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "`*a)'.'^c  
for(int i=0;i<nStartPos.length;i++) gLMea:  
{ Rue|<d1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;s.5\YZ"k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Q1\k`J  
nStartPos,nEndPos,i); =C>`}%XT}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zQ %z"tQ  
fileSplitterFetch.start(); U3+_'"  
} VN-#R=D  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), aevG<|qP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 05VOUa*pb  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", BI.k On=  
nEndPos = " + nFileLength); Dke($Jr{  
// fileSplitterFetch[nPos.length-1].start(); Yj7= T%5  
6aZt4Lw2\  
/,N!g_"Z  
//等待子线程结束 {F+M&+``  
//int count = 0; K0RYI69_  
//是否结束while循环 Dq%r !)  
boolean breakWhile = false; Fxth>O`$  
6`baQ!xc.  
w*xUuwi  
while(!bStop) VIYksv   
{ P[GX}~_k  
write_nPos(); /\a]S:V-j  
Utility.sleep(500); )cqDvH  
breakWhile = true; OV("mNh  
LLn{2,jfQ  
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for(int i=0;i<nStartPos.length;i++) *(&ClUQQ  
{ .4C[D{4  
if(!fileSplitterFetch.bDownOver) tGO[A#9a  
{ ^A"lkV7  
breakWhile = false; n &\'Hm  
break; J6( RlHS;  
} >6l;/J  
} ,rB9esxic  
if(breakWhile) 8Z4?X%  
break; P-OPv%jyi  
&QOWW}  
*&d
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//count++; )y/DGSd  
//if(count>4) f{^M.G@  
// siteStop(); ?%xhe  
} NBqV0>vR  
ZkB6bji  
|;.Pj3)-  
System.err.println("文件下载结束！"); q 5v?`c  
} <f.>jjwFE  
catch(Exception e){e.printStackTrace ();} s\Pt,I@Y_  
} !(]dz~sM  
B=gsd0^]  
|j~EV~AJ  
//获得文件长度 XHZ: mLf  
public long getFileSize() YD='M.n\  
{ +r-dr>&H@  
int nFileLength = -1; Rg?{?qK\K  
try{ MB8SB   
URL url = new URL(siteInfoBean.getSSiteURL()); #NN"(I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G V:$;  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~C"k$;(n  
N$,/Q9h^  
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int responseCode=httpConnection.getResponseCode(); u JQaHL!  
if(responseCode>=400) Y1fy2\<'  
{ @k+%y'Y?  
processErrorCode(responseCode); (3N"oE.b]  
return -2; //-2 represent access is error .A*VLF*m  
} ia^%Wg7  
5qd_>UHp  
XYb^Cs;  
String sHeader; ksu}+i,a  
#6N+5Yx_[  
AvrL9D  
for(int i=1;;i++) y^d[( c  
{ KM/U?`6>:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .L^pMU+!^  
//Utility.log(in.readLine()); bCA2ik  
sHeader=httpConnection.getHeaderFieldKey(i); <g3du~  
if(sHeader!=null) rQcRjh+E H  
{ >d{dZD}  
if(sHeader.equals("Content-Length")) 5e#&"sJ.1  
{ \o:ELa HY  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]{,Gf2v;;d  
break; *^@#X-NG  
} 5?5-;H  
} wc7mJxJxA  
else FJ{,=@  
break; n^iNo  
} z/Ns5  
} >~5lYD  
catch(IOException e){e.printStackTrace ();} QE45!Zg  
catch(Exception e){e.printStackTrace ();} *2,e=tY>  
3!.H^v?  
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Utility.log(nFileLength); +}7Ea:K  
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return nFileLength; [lNqT1%]  
} Lj&1K~U  
n5Nan  
:DdBn.  
//保存下载信息（文件指针位置） ]6t]m2~\  
private void write_nPos() n+{HNr  
{ ~K~b`|1  
try{ L$+d.=]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); K\{b!Cfr^  
output.writeInt(nStartPos.length); W\@?e32  
for(int i=0;i<nStartPos.length;i++) 9Z,*h-o  
{ {W5ydHXy  
// output.writeLong(nPos); eg"=H50  
output.writeLong(fileSplitterFetch.nStartPos); aho'|%y)  
output.writeLong(fileSplitterFetch.nEndPos); bA@ /B'  
} H96BqNoO  
output.close(); RzA2*]%a  
} K*R)V/B/l  
catch(IOException e){e.printStackTrace ();} &W=V%t>Z  
catch(Exception e){e.printStackTrace ();} <w0NPrS]  
} -{X<*P4p  
J [ YtA  
|SGgy|/a#  
//读取保存的下载信息（文件指针位置） 4S,.R  
private void read_nPos() nu&_gF,{  
{ _0'm4?"  
try{ b8J@K"
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); uY^v"cw/F  
int nCount = input.readInt(); _:35d1[  
nStartPos = new long[nCount]; g.64Id  
nEndPos = new long[nCount]; 1.# |QX  
for(int i=0;i<nStartPos.length;i++) "?apgx 6  
{ ]\CU9J|H8  
nStartPos = input.readLong(); :s'o~  
nEndPos = input.readLong(); -O|&c9W.O  
} JDLTOLG  
input.close(); &w+;N5}3  
} t)-*.qZh  
catch(IOException e){e.printStackTrace ();} d"#gO,H0  
catch(Exception e){e.printStackTrace ();} Jy \2I{I'  
} .z=U= _e  
L
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private void processErrorCode(int nErrorCode) 8YNu<   
{ P
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System.err.println("Error Code : " + nErrorCode); vB[~pQ;Z  
} (+|X<Bl:`  
nD7|8,
'  
6}ce1|mkg/  
//停止文件下载 _p\629`  
public void siteStop() B\\6#  
{ _|N}4a  
bStop = true; {jvOHu  
for(int i=0;i<nStartPos.length;i++) 25UYOK}!  
fileSplitterFetch.splitterStop(); C\ tprnY  
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} j5PL
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} ~@{w\%(AK]  
//负责部分文件的抓取 >DHp*$y  
**FileSplitterFetch.java Bd{4Ae\_+g  
*/ ]1m"V;vZ  
package NetFox; C)NC&fV  
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*c{wtl@  
import java.io.*; J^ `hbP+2  
import java.net.*; >ajuk  
*myG"@P4hW  
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public class FileSplitterFetch extends Thread { WvujcmOf  
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String sURL; //File URL eqq`TT#
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long nStartPos; //File Snippet Start Position Frk c
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long nEndPos; //File Snippet End Position F!JJ6d53y  
int nThreadID; //Thread's ID X 7=fX~s  
boolean bDownOver = false; //Downing is over 7|YN:7iA  
boolean bStop = false; //Stop identical @:Di`B_{  
FileAccessI fileAccessI = null; //File Access interface $(ewk):  
^(ScgoXva  
0n.S,3|  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException P.djd$#  
{ baee?6  
this.sURL = sURL; +iy7e6P  
this.nStartPos = nStart; Zmf'{tT5  
this.nEndPos = nEnd; $$hv`HE^l  
nThreadID = id; 3t)v%S|k  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 hrbo:8SL  
} {Hl[C]25X  
UfO7+_2  
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public void run() #O~XVuvF0  
{ yPV'pT)  
while(nStartPos < nEndPos && !bStop) *5e+@rD`  
{ Bd@'e7{  
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try{ X eoJ$PfT  
URL url = new URL(sURL); ;#TaZN  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l?
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httpConnection.setRequestProperty("User-Agent","NetFox"); \?DR s  
String sProperty = "bytes="+nStartPos+"-"; k6!4Zz_8  
httpConnection.setRequestProperty("RANGE",sProperty); T$KF< =  
Utility.log(sProperty); C)Jn[/BD  
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InputStream input = httpConnection.getInputStream(); 3$VxRz)  
//logResponseHead(httpConnection); ,LZX@'5  
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B
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byte[] b = new byte[1024]; H2
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int nRead; 3xNMPm  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q$ri=uB;+  
{ [3N[i(Wlk  
nStartPos += fileAccessI.write(b,0,nRead); /R
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//if(nThreadID == 1) B@O@1?c[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); at6149B\)  
} #`;/KNp 9  
WZZ4]
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)zq.4  
Utility.log("Thread " + nThreadID + " is over!"); y{d^?(-  
bDownOver = true; ~>5#5!}@*  
//nPos = fileAccessI.write (b,0,nRead); at|g%$%  
} ]3B%8  
catch(Exception e){e.printStackTrace ();} <?h%k"5  
} ; |L<:x/  
} LZ U$  
|E@djosyC  
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//打印回应的头信息
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public void logResponseHead(HttpURLConnection con) FJNF%a)x2I  
{ %zeATM[`  
for(int i=1;;i++) C`V)VJM  
{ T*~H m  
String header=con.getHeaderFieldKey(i); %UZVb V  
if(header!=null) ^j)BKD-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); K93p"nHN  
Utility.log(header+" : "+con.getHeaderField(header)); ]"~51HQZ  
else X"q!Y#)  
break; k~3.MU  
} hWo=;#B*  
} Nt:9MG>1  
LfLFu9#:w  
;heHefbvvd  
public void splitterStop() B[5r|d'  
{ xJZ@DR,#  
bStop = true; X|DO~{-au  
} x9W(cKB'S  
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} ?!VIS>C(  
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q<#>HjC  
/* 2F`cv1M  
**FileAccess.java FG@-bV  
*//文件访问(定位，写) !xIm2+:(  
package NetFox; <spZ! #o  
import java.io.*; w}R~C  
$gpG%Qj  
KvPX=/&Zu  
public class FileAccessI implements Serializable{ up'  
$ (=~r`O+1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 a4i:|
  
RandomAccessFile oSavedFile; 5S{7En~zUE  
long nPos; X"fh@.  
[&?8,Q(  
w$Ot{i|$(  
public FileAccessI() throws IOException ,m=4@ofX  
{ -fI@])$9J  
this("",0); j2l55@  
} <M]h{BS=  
RW$:9~  
A@
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public FileAccessI(String sName,long nPos) throws IOException efP&xk  
{ '3IC*o"  
oSavedFile = new RandomAccessFile(sName,"rw"); m
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this.nPos = nPos; LPYbHo3fq  
oSavedFile.seek(nPos); E\nv~Y?SG  
} X>YsQrK(ig  
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t*<#<a  
public synchronized int write(byte[] b,int nStart,int nLen) I zbU)ud  
{ e
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int n = -1; BvrB:%_:  
try{ fFvF\  
oSavedFile.write(b,nStart,nLen); CzCQFqXI  
n = nLen; 6]
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} =qy=-j]  
catch(IOException e) 4_v]O  
{ {O<l[|Ip  
e.printStackTrace (); C:8_m1Y{  
} :,b iyJt  
{gNV[45  
>gwz,{  
return n; D]a<4a18  
} !\8 ;d8  
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} [Y
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/* jn >d*9u  
**SiteInfoBean.java #rO8Kf  
*/ XdLCbY  
package NetFox; #GDe08rOw  
{U<xdG  
`U#55k9^5  
public class SiteInfoBean { Z+j\a5d?,  
h_1T,f(  
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private String sSiteURL; //Site's URL CC\*?BKj"  
private String sFilePath; //Saved File's Path '0y9MXRT  
private String sFileName; //Saved File's Name "<_0A f]  
private int nSplitter; //Count of Splited Downloading File iRg7*MQu  
=[\s8XH,  
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public SiteInfoBean() >>aq,pH  
{//nSplitter的缺省值为5 N>(g?A; Z+  
//default value of nSplitter is 5 :ISMPe3'  
this("","","",5); r78TE@d  
} 7XKY]|S,'  
b"!Q2S~  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8:BIbmtt5  
{ -V,v9h^  
sSiteURL= sURL; Q+b D}emd  
sFilePath = sPath; +aF}oA&X[  
sFileName = sName; ,QzL)W7  
this.nSplitter = nSpiltter; 7\*FEjRM]  
wC `+  
/kt2c[9  
} `(A5f71MfM  
PP:(EN1  
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public String getSSiteURL() uVzFsgBp  
{ >5s6u`\  
return sSiteURL; OpM(j&  
} I;VuW  
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public void setSSiteURL(String value) [,2|Flf e  
{ {hln?'  
sSiteURL = value; AU-n&uX  
} :qChMU|Y6  
d*)CT?d
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nhIa175'  
public String getSFilePath() kJWN.  
{ %dQxJMwj  
return sFilePath; +f*OliMD  
} ^c:Fy+fb  
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public void setSFilePath(String value) z]b>VpW:  
{ |t; ~:
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sFilePath = value; G8Nt 8U~  
} JXyM\}9-X  
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~"UV]Udn  
public String getSFileName() gTA%uRBa  
{ 3%.#}O,(  
return sFileName; It2" x;  
} Or !+._3i  
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8]&i-VFof  
public void setSFileName(String value) uV 7BK+[O  
{ GnP|x}YM  
sFileName = value; 3O7!`Nm@  
} $Of0n` e  
#j *d^j&  
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public int getNSplitter() 5/po2V9)  
{ ?nP*\8  
return nSplitter; ('-JY  
} ;FZ@:%qDm  
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o] mD
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public void setNSplitter(int nCount) 2h[85\4  
{ gY@N~'f;"  
nSplitter = nCount; J>u
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} {uGP&c
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} .BFYY13H  
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tK&'<tZh  
/* 5Ri6Z#qm  
**Utility.java F <hJp,q9  
*/ kWdi595  
package NetFox; vDH>H^9Y  
qhT@;W/X  
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public class Utility { !9xp c
Q>  
~ o1x;Y6  
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public Utility() ` AY_2>7  
{ -eX5z  
C+|b1/N-  
T0&f8  
} @xB*KyUW  
:O(^w}sle  
//线程睡眠 ^5=B`aich  
public static void sleep(int nSecond) d6W SL;$  
{ c+
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try{ b$Vz2Fzx  
Thread.sleep(nSecond); :]J Ye*  
} ?(R]9.5S  
catch(Exception e) JGuN:c$  
{ I_A@BnM{I  
e.printStackTrace (); .l@xsJn  
} _Gu- uuy  
} n5{Xj:}  
6 ~>FYX  
//日志 'Y]mOD^p  
public static void log(String sMsg) NMA}Q$o s  
{ 8>7&E-  
System.err.println(sMsg); 9;veuX#(  
} 1AU#%wIEP  
cq$i  
L:9F:/G  
public static void log(int sMsg) &LbJT$}V  
{ !ET~KL!  
System.err.println(sMsg); [ :zO}
r:  
} K# Jk
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} F{UP;"8'  
e@IA20  
d9q(xZ5  
/* }Q";aU0^  
**TestMethod.java u;`U*@  
*/ /tUy3myJ  
package NetFox; i\dc>C ;  
/c,(8{(O  
lg(bDKm  
public class TestMethod { *k19LI.5  
hXA6D)
  
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public TestMethod() DG?"5:Zd  
{ ///xx/weblogic60b2_win.exe Ps 8%J;  
try{ CP6LHkM9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Qci4J  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); i F+vl]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); n/h,Lr)Z  
fileFetch.start(); f aLtdQi  
} b?Ki;[+O  
catch(Exception e){e.printStackTrace ();} {Lm~r+ U  
&\Amn?Iq  
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} sq;s]@~  
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public static void main(String[] args) Ud!4"<C_  
{ 7[.6axL  
new TestMethod(); `P9XqWr  
} K3=3~uY  
} +-G<c6 |  
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