http断点续传简单实现（java)

/* 5=?P6I_$G  
**SiteFileFetch.java j#//U2VdN  
*/ A]bQUWt2  
package NetFox; zQ=b|p]|W  
import java.io.*; Jt[ug26  
import java.net.*; HUx`RX0>  
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public class SiteFileFetch extends Thread { _x.2&S89  
*HD(\;i-$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -PPwX~;!  
long[] nStartPos; //开始位置 Z,)H f  
long[] nEndPos; //结束位置 +v B}E  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 GKoYT{6  
long nFileLength; //文件长度 |XB<vj07G  
boolean bFirst = true; //是否第一次取文件 ql@2<V{  
boolean bStop = false; //停止标志 'UX^]  
File tmpFile; //文件下载的临时信息 eX$KH;M  
DataOutputStream output; //输出到文件的输出流 toY_1  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?$/::uo  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]H/,Q6Q  
{ gkmof^  
siteInfoBean = bean; UCVYO. 9"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )xcjQkb  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); lR %#R  
if(tmpFile.exists ()) &4OJJ9S  
{ =aVvv+T
 
bFirst = false; 7]rIq\bM  
read_nPos(); nFlN{_/  
} p7YYAh@x\  
else k1z`92"  
{ @K]`
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nStartPos = new long[bean.getNSplitter()]; v`oilsrc  
nEndPos = new long[bean.getNSplitter()]; bD,21,*z  
} Tt~4'{Bc  
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} 3V]dl)en%  
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public void run() RFbf2s\t  
{ ;}Jv4Z  
//获得文件长度 ~m fG Yk"  
//分割文件 Q9cSrU[$  
//实例FileSplitterFetch qXtC7uNj$  
//启动FileSplitterFetch线程 cpk\;1&t  
//等待子线程返回 !mK()#6  
try{ Sd6O?&(  
if(bFirst) W<q<}RSn  
{ G+=Gc(J  
nFileLength = getFileSize(); bg|$1ue  
if(nFileLength == -1)
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{ S
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System.err.println("File Length is not known!"); )L&y@dy)  
} w yxPvI`  
else if(nFileLength == -2) |r+ x/,2-  
{ 4]1/{</B|  
System.err.println("File is not access!"); 6?,qysm06  
} ~;oXLCL0})  
else SXsszb:_  
{ B}04E^  
for(int i=0;i<nStartPos.length;i++) ILCh1=?{9r  
{ N@PuC>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;\th.!'rn  
} .J-k^+-  
for(int i=0;i<nEndPos.length-1;i++) 1V`-D8-?  
{ mZU L}[xf  
nEndPos = nStartPos[i+1]; 5"h4XINZ  
} ddL3wQ  
nEndPos[nEndPos.length-1] = nFileLength; ;X+0,K3c  
} ubB1a_7  
} 7B0`.E^~  
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i@:^b_  
//启动子线程 -$!r+4|q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];  2l,>x  
for(int i=0;i<nStartPos.length;i++) N]yT/8  
{ e_!h>=$%8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lfBCzxifC  
nStartPos,nEndPos,i); t!wbT79/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pOK=o$1V8  
fileSplitterFetch.start(); ;ZB=@@l(  
} Vw;iE=L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ot7f?tF2<J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); PoZ$3V$(Lz  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", fKEDe
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nEndPos = " + nFileLength);
%(s|  
// fileSplitterFetch[nPos.length-1].start(); =X(N+(1~  
yPfx!9B  
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//等待子线程结束 `/1rZ#  
//int count = 0; Q:)4  
//是否结束while循环 nGGw(
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boolean breakWhile = false; mqeW,89  
();Z,A  
2L^/\!V#  
while(!bStop) >W+,(kAS  
{ e}O&_j-  
write_nPos(); )T '?"guh`  
Utility.sleep(500); 0qR#o/~I  
breakWhile = true; X,@nD@  
@j\;9>I/  
3
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for(int i=0;i<nStartPos.length;i++) tY#&_%W  
{ #}.{|'L  
if(!fileSplitterFetch.bDownOver) R;AcAJ;  
{ lYe2;bu  
breakWhile = false; @}jg5}  
break; &pl)E$Y  
} <.g)?nj1  
} <Y /3U  
if(breakWhile) 5<X"+`=9  
break; >l}v _k*~B  
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3q'nO-KJ  
//count++; ral=`/p  
//if(count>4) FXk*zXn6  
// siteStop(); v+EJ $  
} y=8KNse
W|  
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System.err.println("文件下载结束！"); #U'}g *  
} L?N:4/0;!  
catch(Exception e){e.printStackTrace ();} *#p}FB2H#  
} D0\*WK$  
UptKN|S&V  
 Dt5AG  
//获得文件长度 c&#Q`m  
public long getFileSize() GwgY{-|`  
{ 6I~M8Lo;  
int nFileLength = -1; z__{6"^  
try{ ^Gbcs l~Gj  
URL url = new URL(siteInfoBean.getSSiteURL()); 9XUYy2{G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); XwIHIG}  
httpConnection.setRequestProperty("User-Agent","NetFox"); rU>l(O'b  
_ y'g11 \  
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int responseCode=httpConnection.getResponseCode(); 5:+x7Ed  
if(responseCode>=400) g:^Hex?Yfd  
{ &iuMB0rbu  
processErrorCode(responseCode); R8.@5g_  
return -2; //-2 represent access is error c~M'O26bW  
} Y}}1]}VIK  
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String sHeader; (eT9N_W  
5!i\
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&6GW9pl[  
for(int i=1;;i++) 4D.h~X4  
{ U2Siw  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); i @M^l`w  
//Utility.log(in.readLine()); abe5 As r  
sHeader=httpConnection.getHeaderFieldKey(i); +IGSOWL  
if(sHeader!=null) d<]eJ{  
{ KVC18"|f  
if(sHeader.equals("Content-Length")) c]ll89`||  
{ N+UBXhh
  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));
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break; \J~@r1  
} 7CU<R9Kl  
} BMzS3;1_  
else
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break; 8N<2RT8W  
} .4z_ohe  
} gf;B&MM6  
catch(IOException e){e.printStackTrace ();} fob.?ID-;  
catch(Exception e){e.printStackTrace ();} NmNj0&  
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Utility.log(nFileLength); 2j^8{Agz  
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return nFileLength; Q:b>1  
} _P_R`A)"  
<7%#RJwe  
Zh:@AFz:R  
//保存下载信息（文件指针位置） RLh%Y>w  
private void write_nPos() #FGj)pu  
{ 3 lKBwjW  
try{ CTB qX  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !&G& ~*.x  
output.writeInt(nStartPos.length); %Bnn\{Az  
for(int i=0;i<nStartPos.length;i++) UN6nh T  
{ DS<
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// output.writeLong(nPos); GQ9H>Ssz  
output.writeLong(fileSplitterFetch.nStartPos); )"bP]t^_  
output.writeLong(fileSplitterFetch.nEndPos); {us#(4O  
} 9Kc;]2
m  
output.close(); meD?<g4n~"  
} s9b+uUt%  
catch(IOException e){e.printStackTrace ();} avMre_@V  
catch(Exception e){e.printStackTrace ();} tiic>j\D  
} |r`0< `  
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as  
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//读取保存的下载信息（文件指针位置） (ap,3$hS  
private void read_nPos() Vg`32nRN  
{ yD^Q&1  
try{ a[BIY&/Q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); QlnI&o  
int nCount = input.readInt(); %vWh1-  
nStartPos = new long[nCount]; #"J
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nEndPos = new long[nCount]; r[&/*~xL  
for(int i=0;i<nStartPos.length;i++) /:w.Zf>B9  
{ O=}jg0k  
nStartPos = input.readLong(); C/z0/mk  
nEndPos = input.readLong(); h"
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} K"=I,Vr:  
input.close();  4V 5  
} -[A=\]RfJ  
catch(IOException e){e.printStackTrace ();} @3Mp>u/  
catch(Exception e){e.printStackTrace ();} \BdQ(rm  
} ~hQTxLp  
jW.IkG[|  
d/I*$UC  
private void processErrorCode(int nErrorCode) {dNWQE*\c  
{ )WF*fcx{  
System.err.println("Error Code : " + nErrorCode); KZsJ_t++!W  
} K1|xatx1V  
?wj1t!83  
$s9YU"  
//停止文件下载 "xMnD(p  
public void siteStop() [G}l;  
{ k%sh;1.  
bStop = true; uRRp8hht  
for(int i=0;i<nStartPos.length;i++) #7,;/rtO7  
fileSplitterFetch.splitterStop(); 8CGjI?j  
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} G+W0X  
} "D/\&1.&  
//负责部分文件的抓取 !L55S03  
**FileSplitterFetch.java {edjvPlk  
*/ ,gbQqoLV  
package NetFox; r=^?  
A}(Q^|6  
MN. $a9m  
import java.io.*; N:e5=;6s  
import java.net.*; L=-v>YL+  
\m3ca-Y  
0r'<aA`=I  
public class FileSplitterFetch extends Thread { !:<n]-U  
 <sC.  
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String sURL; //File URL <lHVch"(^$  
long nStartPos; //File Snippet Start Position <(dg^;  
long nEndPos; //File Snippet End Position L[.RV*sL  
int nThreadID; //Thread's ID ^q)s  
boolean bDownOver = false; //Downing is over l]__!X  
boolean bStop = false; //Stop identical u
+,  
FileAccessI fileAccessI = null; //File Access interface bZzB\FB~  
_(J/$D  
1usLCG>w{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 9/I|oh_ G  
{ w4\g]\  
this.sURL = sURL; C.q4rr  
this.nStartPos = nStart; .Fn7yTQ%  
this.nEndPos = nEnd; )i*-j=  
nThreadID = id; 4l
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 H.]rH,8  
} 4ai|*8.  
!p|d[  
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public void run() gKWsmx!["  
{ :PF6xL&  
while(nStartPos < nEndPos && !bStop) OykYXFv*  
{ ^+'\ u;\  
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try{ 4n,>EA85  
URL url = new URL(sURL); :7jDgqn^|i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `
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httpConnection.setRequestProperty("User-Agent","NetFox");
h}cR>  
String sProperty = "bytes="+nStartPos+"-"; =^S1+B MY-  
httpConnection.setRequestProperty("RANGE",sProperty); "3X~BdH&J  
Utility.log(sProperty); KO5! (vi@  
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Q"=$.M~  
InputStream input = httpConnection.getInputStream(); %[H|3  
//logResponseHead(httpConnection); [BzwQ 4  
4-veO3&.h  
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byte[] b = new byte[1024]; 3"y,UtKGa  
int nRead; Ht=h9}x"
g  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) S[5e,Ew  
{ `hE@S |4  
nStartPos += fileAccessI.write(b,0,nRead); ^ woCwW8n  
//if(nThreadID == 1) tunjV1 ,]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); wwD?i.3  
} P\2UIAPa\b  
LyWgaf#/d  
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Utility.log("Thread " + nThreadID + " is over!"); hqVxvS"  
bDownOver = true; ;@l5kdZx`  
//nPos = fileAccessI.write (b,0,nRead);  pu?D^h9/  
} nN$aZSb`  
catch(Exception e){e.printStackTrace ();} -TU^*  
} ]3bXJE  
} i"J`$u  
j$jgEtPK9=  
#Qnl,lf  
//打印回应的头信息  {;| >Qn  
public void logResponseHead(HttpURLConnection con) Y+0HC
2
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{ <9jN4hV  
for(int i=1;;i++) 1xzOD@=dI  
{ n/jZi54gO  
String header=con.getHeaderFieldKey(i); y
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if(header!=null) U9eb&nd  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); sxFkpf_h  
Utility.log(header+" : "+con.getHeaderField(header)); `37$YdX  
else CFyu9Al  
break; akB+4?+s)  
} yTwtGo&  
} $Y9Wzv3Ra  
A-om?$7  
+Ssu^>D  
public void splitterStop() n+9rx]W,  
{ -K*&I!  
bStop = true; !au%D?w  
} N497"H</  
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} s%l`XW;v  
5`H.{4@  
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/* _q<Ke/  
**FileAccess.java 1'Y7h;\~\  
*//文件访问(定位，写) QdtGFY4f,  
package NetFox; GB\
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import java.io.*; h#Q Sx@U6  
>hsvRX\_`  
y|(C L^(  
public class FileAccessI implements Serializable{ eB,eu4+-  
?vr9l7VOi  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 D +Ui1h-  
RandomAccessFile oSavedFile; w:+wx/\  
long nPos; Ti!<{>  
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public FileAccessI() throws IOException '&42E[0P  
{ gUtxyW  
this("",0); `@)>5gW&p  
} 9~ JeI/  
7ts`uI<E@7  
oW\kJ>!  
public FileAccessI(String sName,long nPos) throws IOException Kp)H>~cL  
{ R-lpsvDDL2  
oSavedFile = new RandomAccessFile(sName,"rw"); |h(05Kbk  
this.nPos = nPos; tVFydN~  
oSavedFile.seek(nPos); 4<(U/58a*  
} V4>qR{5  
Hu-Y[~9^L:  
LCouDk(=`  
public synchronized int write(byte[] b,int nStart,int nLen) q9iHJ'lMD*  
{ MQvk& AX  
int n = -1; !5zDnv  
try{ F*rsi7#!pG  
oSavedFile.write(b,nStart,nLen); -}$mv  
n = nLen; a7YzX5n  
} {$fd?| 9h  
catch(IOException e) Q$XNs%7w5,  
{ (N 0kTi]b  
e.printStackTrace (); gof'NT\c  
} %&Q9WMo  
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*iwVB^^$  
return n; ILyI%DA&  
} q-|j =  
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} nC2e^=^  
tS:/:0HnA)  
,!7\?=G6}v  
/* Cyu= c1D;  
**SiteInfoBean.java fv+t%,++:  
*/ {#C)S&o)6  
package NetFox; (YC{BM}  
0LD$"0v/C3  
L=#nnj-  
public class SiteInfoBean { = iXHu *g  
wJMk%N~R:  
CD:$22*]  
private String sSiteURL; //Site's URL v{c,>]@
 
private String sFilePath; //Saved File's Path 3[;fO_R  
private String sFileName; //Saved File's Name ScCA8JgY  
private int nSplitter; //Count of Splited Downloading File G%FLt[  
S\"#E:A  
]21`x  
public SiteInfoBean() DqN<bu2  
{//nSplitter的缺省值为5 " .<>(bE  
//default value of nSplitter is 5 "%E<%g  
this("","","",5); _-c1" Kl  
} |D1:~z  
a4E{7c  
iRK&-wn  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) KJ#SE|  
{ oGvk,mh"(  
sSiteURL= sURL; @t{`KB+ ^  
sFilePath = sPath; "OWW -m  
sFileName = sName; A!uO7".E  
this.nSplitter = nSpiltter; VqL#w<A%  
"J"RH:$v  
(\M#Ay t)  
} Mfinh@K,  
l?<DY$H 0  
'dvi@Jx  
public String getSSiteURL() _MLbJ  
{ v9 *WM3  
return sSiteURL; L"Dos
+  
} dKJ-{LV  
M'|?*aNK  
!=bGU=^  
public void setSSiteURL(String value) ;}KT 3Q<^  
{ [MXyOE  
sSiteURL = value; 4l rKU^-  
} VKMgcfbHr/  
CEh!X=Nn  

7#+>1 "\  
public String getSFilePath() C'.^2s#e8  
{
'PWX19  
return sFilePath; <IO@Qj1*  
} S;iJQS   
TD.t)  
Dn[uzY6  
public void setSFilePath(String value) ~i UG24v  
{ UZRN4tru6  
sFilePath = value; z2~\ b3G  
} dJ.up*aR  
P{+,?X\  
WJTc/  
public String getSFileName() 8DGPA  
{ r)|6H"n#]S  
return sFileName; 8e"M
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} 1YS
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noZ!j>f{@l  
SQ
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public void setSFileName(String value) l1%ubu  
{ g#l
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sFileName = value; kca
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} /*e6('9s  
%;,4qB  
7* R %zJ  
public int getNSplitter() YVLK X}$)(  
{ &fe67#0r)  
return nSplitter; >X
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} wnjAiIE5  
G#YBfPmr  
oS^g "hQ`\  
public void setNSplitter(int nCount) GJIZu&C  
{ q+2v9K@  
nSplitter = nCount; BG_6$9y  
} ]]9VI0   
} W4q |55  
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Ij2Th]  
/* a"m-&mN  
**Utility.java ]jSRO30H3<  
*/ -unQ4G  
package NetFox;  %m##i  
$6]1T
>  
*r)dtI*  
public class Utility { I{i6e'.jP  
}poLHS/  
5}TTf2&Xo#  
public Utility() "Pl.G[Buc-  
{ U;#G$  
s\e b  
%?Q<  
} HdRwDW@7=  
#xh M&X  
//线程睡眠 6apK  
public static void sleep(int nSecond) A [_T~+-G  
{ xg;vQKS6  
try{ ;sAe#b  
Thread.sleep(nSecond); ?OFfU  4  
} Y^b}~t  
catch(Exception e) LcTTfb+<  
{ h{: ]'/@~  
e.printStackTrace (); Y-+JDrK  
} Z5eM  
} 0[p"8+x  
N<XMSt  
//日志 X7txAp.  
public static void log(String sMsg) ^t?vv;@}  
{ WsW] 1p  
System.err.println(sMsg); M_h8{  
} U#`2~Qv/1  
d%:J-UtG"  
70{B/ ($  
public static void log(int sMsg) l[^0Ik-G  
{ )JhB!P(  
System.err.println(sMsg); <B!DwMk;.  
} S@Aw1i p  
} Z|xgZG{  
&aPR"X  
]IH1_?HgP7  
/* n7.85p@ua  
**TestMethod.java vs@u*4.Ut<  
*/ R`M@;9I.@  
package NetFox; K%UjPzPWw  
XB]>Z)  
6Zx5^f(qd  
public class TestMethod { dEkAUH  
h:i FLSf  
&t6:1T  
public TestMethod() ji<(}d~L*  
{ ///xx/weblogic60b2_win.exe 
:mhO/Bx  
try{ =s9*=5r8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); sF3@7~m4  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); e.W<pI,  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,[<$X{9  
fileFetch.start(); -/:K.SY,
 
} QZJnb%]  
catch(Exception e){e.printStackTrace ();} KE-0/m4yJ  
)hC3'B/[Y  
& jm1  
} mV+9*or  
:i|Bz6Ht4  
v8zOY#?  
public static void main(String[] args) LtPaTe  
{ Hc-up.?v'v  
new TestMethod(); yq[. WPve  
} lYmxd8  
} :<HLw.4O  
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