http断点续传简单实现（java)

/* lVOu)q@l7g  
**SiteFileFetch.java nKa$1RMO  
*/ 2*w0t:Yxe  
package NetFox; Dre2
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import java.io.*; z2_6??tS/c  
import java.net.*; a2IgC25  
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public class SiteFileFetch extends Thread { 5"XC$?I<}  
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SiteInfoBean siteInfoBean = null; //文件信息Bean El\%E"Tk%  
long[] nStartPos; //开始位置 yAL[[  
long[] nEndPos; //结束位置 &>d:R_Q]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >NYW{(j  
long nFileLength; //文件长度 F8-?dpf'  
boolean bFirst = true; //是否第一次取文件 -Eu6U`"(  
boolean bStop = false; //停止标志 ~5FW[_  
File tmpFile; //文件下载的临时信息 #Cpd9|  
DataOutputStream output; //输出到文件的输出流 @+3kb.P%7  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 1 zw*/dp  
public SiteFileFetch(SiteInfoBean bean) throws IOException *(C(tPhC  
{ wE+${B03  
siteInfoBean = bean; .*m>\>Gsgw  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J'$>Gk]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ;AO#xv+#  
if(tmpFile.exists ()) !?c|XdjZ  
{ q9Y9w(  
bFirst = false; ^nbnbU4'  
read_nPos(); `]Q:-h  
} V"c 6Kdtd  
else =[b)1FUp  
{ RuII!
}*  
nStartPos = new long[bean.getNSplitter()]; (x/k.&  
nEndPos = new long[bean.getNSplitter()]; X 1 57$  
} ,]bB9tid  
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} C74a(Bk}H  
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public void run() wgCa58H76  
{ M#(+c_(r  
//获得文件长度 *G* k6.9W!  
//分割文件 8Z(Mvq]f&  
//实例FileSplitterFetch :q#Xq;Wp  
//启动FileSplitterFetch线程 6I@h9uIsze  
//等待子线程返回 n{6G"t:^l  
try{ g+J-Zg6  
if(bFirst) 0u\GO;  
{ ?@E!u|]K  
nFileLength = getFileSize(); E?_Z`*h  
if(nFileLength == -1) gNt(,_]ZR  
{ ZYC<Wb)I  
System.err.println("File Length is not known!"); 1t)il^p4[;  
} xlQBe-Wg  
else if(nFileLength == -2) 293M\5:  
{ #O+),,WS  
System.err.println("File is not access!"); )c `7( nY  
} 7(pF[LCF  
else yu;P +G  
{ xg3:}LQ  
for(int i=0;i<nStartPos.length;i++)
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{ Oil?JI Hq  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); euC&0Ee2  
} Hv2De0W  
for(int i=0;i<nEndPos.length-1;i++) uD^cxD  
{ yU9DSY\m{  
nEndPos = nStartPos[i+1]; )ubiB^g'm  
} Q)IKOt;N]  
nEndPos[nEndPos.length-1] = nFileLength; xL\0B,]  
} thI F&  
} Evedc*z~P  
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//启动子线程 )c)vTZy  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; s,]z[qB#$  
for(int i=0;i<nStartPos.length;i++) zx)z/
1  
{ Y\No4w ^|d  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), , GP?amh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), HhvdqvIEG  
nStartPos,nEndPos,i); neLAEHV  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >U[j]V]  
fileSplitterFetch.start(); %^ !,t:d  
} Dy:|g1>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FY#C.mL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 5yP\I+Fm  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]x(!&y:h  
nEndPos = " + nFileLength); {0WHn.,2Y  
// fileSplitterFetch[nPos.length-1].start(); $42{HFGq  
;IZwTXu!S  
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//等待子线程结束 T
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//int count = 0; `~By)?cT_>  
//是否结束while循环 /w}u3|L$  
boolean breakWhile = false; 5:KQg  

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while(!bStop) @X#F3;  
{ }f6HYU  
write_nPos(); <nT +$   
Utility.sleep(500); R8a3 1&  
breakWhile = true; .nx2";oi  
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for(int i=0;i<nStartPos.length;i++) G$F<$  
{ Wa{`VS  
if(!fileSplitterFetch.bDownOver) [q8 P~l  
{ )QU  
breakWhile = false; P&*2pX:  
break; @emK1iwm  
} Ezd_`_@R  
} D$I5z
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if(breakWhile) wNpTM8rfU#  
break; Y,^@P  
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!xo{-@@wS  
//count++; /}b03  
//if(count>4) rrik,qyv6  
// siteStop(); Nh_Mz;ITuu  
} B#Vz#y  
c7x~{V8  
4R1<nZ"e~  
System.err.println("文件下载结束！"); vunHNHltW0  
} Lr~=^{  
catch(Exception e){e.printStackTrace ();} (ROY?5 @c  
} 4NheWM6  
UCB/=k^m  
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//获得文件长度 Bg x'9p/  
public long getFileSize() \J
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{ 1W^taJH]  
int nFileLength = -1; P-yjN  
try{ uKUiV%p!  
URL url = new URL(siteInfoBean.getSSiteURL()); g| I6'K!<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O;:mCt _H  
httpConnection.setRequestProperty("User-Agent","NetFox"); (MxQ+D\  
MOQ*]fV:  
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int responseCode=httpConnection.getResponseCode(); | *2w5iR  
if(responseCode>=400) }v}P .P  
{ R;&AijS8  
processErrorCode(responseCode); ^ *k?pJ5  
return -2; //-2 represent access is error K*LlW@  
} yerg=,$_i  
,Z&xNBX  
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String sHeader; 1ySk;;3  
'YmIKIw  
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for(int i=1;;i++) cQy2"vtU  
{ zPn+V7F  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "O3tq=Q  
//Utility.log(in.readLine()); vW
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sHeader=httpConnection.getHeaderFieldKey(i); ` Mjj@[  
if(sHeader!=null) *
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{ 2_HNhW  
if(sHeader.equals("Content-Length")) q
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{ +" .X )avF  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !Xf5e*1IS  
break; `u3E
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} y\4L{GlBM  
} )~)J?l3{  
else f-vCm 5f  
break; Dp,L/1GQ8  
} 89pEfl j2  
} %g{X?  
catch(IOException e){e.printStackTrace ();} h7G"G"  
catch(Exception e){e.printStackTrace ();} _|kxY'_[8  
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Utility.log(nFileLength); >JHryS.j$4  
:~"CuB/  
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return nFileLength; -$,TMqM  
} \)#kquH/l  
1H? u Qy  
?~BC#B\>o  
//保存下载信息（文件指针位置） Gw/Pk4R  
private void write_nPos() I0D(F i  
{
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try{ _mqL8ho  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2VmNZ{<  
output.writeInt(nStartPos.length); LO9=xGj.  
for(int i=0;i<nStartPos.length;i++) JU1~e@/'%  
{ Z]>O+  
// output.writeLong(nPos); |mxDjgq  
output.writeLong(fileSplitterFetch.nStartPos); o
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output.writeLong(fileSplitterFetch.nEndPos); XKj|f`  
} ]#)()6)2v  
output.close(); BTqS'NuT  
} ! `  
catch(IOException e){e.printStackTrace ();} ] {RDVA=]  
catch(Exception e){e.printStackTrace ();} TaZmRL  
} !"?#6-,Xn  
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//读取保存的下载信息（文件指针位置） ^S4d:-.3  
private void read_nPos() b[r8e  
{ PCHu#5j_a  
try{ w1Nm&}V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g0xuxK;9c  
int nCount = input.readInt(); "h{q#~s  
nStartPos = new long[nCount]; hO\<%0F  
nEndPos = new long[nCount]; .F4>p=r  
for(int i=0;i<nStartPos.length;i++) GFj{K
 
{ cM(:xv  
nStartPos = input.readLong(); OcR$zlgs[v  
nEndPos = input.readLong(); %<\vGqsM  
} [\^n=  
input.close(); h]IxXP?h[  
} ^cOUQ33  
catch(IOException e){e.printStackTrace ();} u@Ih GME  
catch(Exception e){e.printStackTrace ();} \pa"%c)  
} :%lTU  
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private void processErrorCode(int nErrorCode) .0zY}`  
{ }^ApJS(FQ  
System.err.println("Error Code : " + nErrorCode); pNG:0  
} 7Od -I*bt  
y;35WtDVb  
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//停止文件下载 X&tF;<m^  
public void siteStop() Ep9nsX*   
{ ;km`P|
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bStop = true; zJq~!#pZ  
for(int i=0;i<nStartPos.length;i++) QyEnpZ8?a  
fileSplitterFetch.splitterStop(); &jS>UsGh  
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} LdYB7T,  
} v> LIvi|]  
//负责部分文件的抓取 "3X2VFwo
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**FileSplitterFetch.java VACQ+  
*/ &|s
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package NetFox; lUOF4U&r  
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import java.io.*; E-T)*`e  
import java.net.*; u4t7Ie*Q  
;,hwZZ
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public class FileSplitterFetch extends Thread { Ot4 Z{mA  
XQY#716)  
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String sURL; //File URL \o z#l'z  
long nStartPos; //File Snippet Start Position Y@;CF  
long nEndPos; //File Snippet End Position &C`Gg<  
int nThreadID; //Thread's ID E(*0jAvO[z  
boolean bDownOver = false; //Downing is over wg9t)1k{e  
boolean bStop = false; //Stop identical *D'22TO[[!  
FileAccessI fileAccessI = null; //File Access interface 9&$y}Y  
G!Op~p@Jm  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0eT(J7[ <  
{ 'j`=if
 
this.sURL = sURL; !O\82d1P  
this.nStartPos = nStart; vDp8__^  
this.nEndPos = nEnd; bg!/%[ {M  
nThreadID = id; W,K;6TZhh  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 JgxtlYjl  
} \Z?9{J  
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public void run() W =D4r  
{ 6|gCuT4  
while(nStartPos < nEndPos && !bStop) TJ2=m9Z  
{ {0[tNth'h  
>BV^H.SO|1  
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try{ 5VfyU8)7X  
URL url = new URL(sURL); S(k3 `;K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .yMEIUm  
httpConnection.setRequestProperty("User-Agent","NetFox"); OC_+("N  
String sProperty = "bytes="+nStartPos+"-"; zykT*V  
httpConnection.setRequestProperty("RANGE",sProperty); piJu+tUy  
Utility.log(sProperty); ~Q Oe##  
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InputStream input = httpConnection.getInputStream(); 8+~ >E  
//logResponseHead(httpConnection); wy<\Tg^J  
h\$$JeSV]  
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byte[] b = new byte[1024]; `68@+|#  
int nRead; .u)X3..J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) iJ ($YvF4  
{ x!?u^  
nStartPos += fileAccessI.write(b,0,nRead); f&=AA@jLv  
//if(nThreadID == 1) XPavReGf  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +vw\y  
} uFX#`^r`  
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Utility.log("Thread " + nThreadID + " is over!"); "0V.V>-p  
bDownOver = true; y8d]9sX{  
//nPos = fileAccessI.write (b,0,nRead); [meO[otb  
} ;o 6lf_  
catch(Exception e){e.printStackTrace ();} 7LfAaj  
} ;@0;pY  
} `Syl:rU~y@  
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OyU5DoDz1  
//打印回应的头信息 J-[,KME_^  
public void logResponseHead(HttpURLConnection con) l?E{YQq]  
{ H[NSqu.s  
for(int i=1;;i++) o$wEEz*4  
{ 7z%L*z8V  
String header=con.getHeaderFieldKey(i); C>ICu*PW  
if(header!=null) a]$1D!Anc  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); jrCfW
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Utility.log(header+" : "+con.getHeaderField(header)); Ja|5 @  
else ;"xfOzQ  
break; \Q {m9fE  
} _jvxc'6  
} A9[ F  
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public void splitterStop() >Ifr [  
{ ]>W6 bTK  
bStop = true; C+*d8_L  
} B~?*?Z'  
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} 5u,{6  
1;JEc9#h  
l94b^W}1)W  
/* 1ufp qqk  
**FileAccess.java J9..P&c\  
*//文件访问(定位，写) UZWioxsKr+  
package NetFox; I~[F|d>  
import java.io.*; R]JT&p|w.1  
; 8_{e3s  
}V'}E\\  
public class FileAccessI implements Serializable{ g6yB6vk  
|sa]F5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 n#cC+>*>+  
RandomAccessFile oSavedFile; ):P?  
long nPos; # ncRb  
l.(v^3:X  
*o]L|Vu  
public FileAccessI() throws IOException >;jZa  
{ 3(``#7  
this("",0); ?'IP4z;y  
} M5i%jZk  
[ieI;OG;  
5v[*:0p'  
public FileAccessI(String sName,long nPos) throws IOException ajve~8/&  
{ :)8VdWg  
oSavedFile = new RandomAccessFile(sName,"rw"); _aq8@E~  
this.nPos = nPos; Vo4,@scG  
oSavedFile.seek(nPos); j SHk{T!J  
} .L+6 $8m  
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public synchronized int write(byte[] b,int nStart,int nLen) l\f*
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{ B=U 3  
int n = -1; y3vdUauOn  
try{ dR K?~1  
oSavedFile.write(b,nStart,nLen); bes<qy  
n = nLen; 4M^=nae  
} oxr#7Ei0d  
catch(IOException e) yyR0]NzYUD  
{ I.I`6(Cb  
e.printStackTrace (); )i6mzzj5  
} &`h{iK7  
!'Ak&j1:`  

''|W9!  
return n; f<GhkDPm>?  
} &g#@3e1>  
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} _qU4Fadgm  
C=-=_>Q,L<  
3W V"U  
/* zlyS}x@p  
**SiteInfoBean.java 3Nl <p"=  
*/ p$O.> [  
package NetFox; 3N8t`N  
"WlZ)wyF%  
6d:zb;Iz  
public class SiteInfoBean { <<UB ^v m  
6o^,@~:R  
AWcLUe{  
private String sSiteURL; //Site's URL 5sdn[Tt##  
private String sFilePath; //Saved File's Path 4"GR] X  
private String sFileName; //Saved File's Name W,D4.w$@'  
private int nSplitter; //Count of Splited Downloading File I
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?llXd4  
i|c'Lbre`  
public SiteInfoBean() y+Ra4G#/}  
{//nSplitter的缺省值为5 Yy5h"r  
//default value of nSplitter is 5 }~2LW" 1'  
this("","","",5); K)6rY(x >  
} :X"?kK0V  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ih)zG  
{ $Y;U[_l#  
sSiteURL= sURL; v/@^Q1G/:  
sFilePath = sPath; y>:N{|  
sFileName = sName; j 7fL7:,T  
this.nSplitter = nSpiltter; $yN{-T"  
K'55O&2  
#:jHp44J  
} :1^LsLr5  
><RpEnWZ<  
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public String getSSiteURL() p5Z"|\  
{ <5d~P/,  
return sSiteURL; YD<:,|H  
} Moy <@+  
svsqg{9z  
@>u}eB>Kn  
public void setSSiteURL(String value) ,NOsFO-`<  
{ ~Io7]  
sSiteURL = value; j_/>A=OD  
} Yf:IKY  

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public String getSFilePath() @_-hk|Nl@  
{ x`U^OLV  
return sFilePath; d+<G1w&z  
} %fc!2E9|  
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8G9s<N}5&u  
public void setSFilePath(String value) QaS1
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{ x%s-
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sFilePath = value; \?w2a$?6w  
} 63^O|y\W8  
>l]Xz*HE  
\jh'9\  
public String getSFileName() >/g#lS 5  
{ +"x,x  
return sFileName; Z.c'Hs+;  
} 6rh5h:  
W~6
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A]<y:^2])C  
public void setSFileName(String value) b v G/|U  
{ t 4PK}>QW  
sFileName = value; bhID#&  
} nx@=>E+a  
g~ZvA(`  
56
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public int getNSplitter() NYyh|X:m  
{ gRrL[z  
return nSplitter; g
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>  
} X]'{(?Ch  
T,7Y7c/3V  
%;cddLQ\xY  
public void setNSplitter(int nCount) %.vQU @2A  
{ .nB0 h  
nSplitter = nCount; 83E7k]7]  
} uya.sF0]9B  
} u0 P|0\  
bmJ5MF]_fG  
_|iSF2f,X  
/* zxJ]"N  
**Utility.java wi;Br[d  
*/ 6{
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package NetFox; ,
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rk&IlAE  
public class Utility { N6>(;ugJ1-  
f) znTJL  
"*($cQ$v  
public Utility() )n+Lo&C<  
{ wy yWyf
  
|P[w==AAf  
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} C+'/>=>a.  
~{d$!`|a  
//线程睡眠 %Da8{%{`Pc  
public static void sleep(int nSecond) kr+D,h01  
{ 6tB+JF  
try{ E;,u2[3  
Thread.sleep(nSecond); $g/S
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} t|a2;aq_  
catch(Exception e) 8u"!dq  
{ q_TRq:&.  
e.printStackTrace (); XJ;D=~  
} 1s%#$ 7  
} {K <iih  
jB`,u|FG  
//日志 wr5AG<%(  
public static void log(String sMsg) +s(HO
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{ }0eF~>Df  
System.err.println(sMsg); y6LWx:  
} lH-/L(h2  
i8`Vv7LF  
?$vCW|f  
public static void log(int sMsg) [OM7g'?S0  
{ rv&<{@AS~  
System.err.println(sMsg); _hN\10ydY  
} G.rrv  
} XR+Y=R  
Kw-gojZ  
$@"l#vJPfc  
/* Y-pzy']4  
**TestMethod.java .JYaH?  
*/ }B8IBveu  
package NetFox; IT(lF
 
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public class TestMethod { [ad@*KFxy3  
U[SaY0Z  
:QpuO1Gu  
public TestMethod() e91aK  
{ ///xx/weblogic60b2_win.exe {/"2Vk<H8  
try{ )#P; x"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1>*#%R?W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9XPo3;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ~R_ztD+C(  
fileFetch.start(); lV`Q{bd+  
} H(bs$C4F  
catch(Exception e){e.printStackTrace ();} F5?m6`g?  
p!>oo1&  
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} =G]1LTI  
FB
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s8-<m,*  
public static void main(String[] args) _(Sa4Vb=Q6  
{ uxW~uEh  
new TestMethod(); Z9MdD>uwi  
} %C$%!C  
} H18Tn!RDS  
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