http断点续传简单实现（java)

/* OJ/SYZ.r  
**SiteFileFetch.java -=)-sm'  
*/ ,[`$JNc  
package NetFox; J#aVo&.Y  
import java.io.*; :c7CiP  
import java.net.*; ,w2WS\`%  
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public class SiteFileFetch extends Thread { (Z-l/)Q  
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SiteInfoBean siteInfoBean = null; //文件信息Bean kH?#B%N5  
long[] nStartPos; //开始位置 P`TIaP9%E  
long[] nEndPos; //结束位置 [w+Q^\%bN  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 qC@Ar)T  
long nFileLength; //文件长度 V=}1[^  
boolean bFirst = true; //是否第一次取文件 hz\WZ^  
boolean bStop = false; //停止标志 vM`~)rO@!  
File tmpFile; //文件下载的临时信息 !M;A*:-  
DataOutputStream output; //输出到文件的输出流 Sj-[%D*  
o| D^`Z  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `,Orf ZMb  
public SiteFileFetch(SiteInfoBean bean) throws IOException ]V<-J   
{ ssl&5AS  
siteInfoBean = bean; /P+q}L%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); aB"xqh)a}T  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); K]fpGo  
if(tmpFile.exists ()) ut&/\k=N  
{ KcXpH]>!9  
bFirst = false; 6G_<2bO  
read_nPos(); >I<PO.c!  
} S " pI  
else GGnp Pp  
{ s@!$='|  
nStartPos = new long[bean.getNSplitter()]; \##5O7/1  
nEndPos = new long[bean.getNSplitter()]; `ZGcgO<c\  
} n%$ &=-Fk  
({[,$dEa;  
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} p2d\ZgWD=)  
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public void run() [,g~m9  
{ keCRvlZ4  
//获得文件长度 QxpKX_@Q5  
//分割文件 ai^|N.!  
//实例FileSplitterFetch tZho
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//启动FileSplitterFetch线程 `\b+[Ne
s  
//等待子线程返回 m{(+6-8|m  
try{ KCtX$XGL  
if(bFirst) `|Fp^gM  
{ qO()w  
nFileLength = getFileSize(); kGHC]Fb)  
if(nFileLength == -1) C1fyV]  
{ PC/!9s0W  
System.err.println("File Length is not known!"); c K<)$*  
} -:`V<  
else if(nFileLength == -2) u#jC#u^M  
{
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System.err.println("File is not access!"); t9u|iTY f!  
} Ade}g'  
else (:sZ b?*  
{  MCnN^  
for(int i=0;i<nStartPos.length;i++) x$B&L`QV  
{ tZ8e`r*  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 4v.d-^  
} D}{b;Un  
for(int i=0;i<nEndPos.length-1;i++) }ugxN0  
{ M-MKk:o  
nEndPos = nStartPos[i+1]; @ 4UxRp6+  
} "J19*<~  
nEndPos[nEndPos.length-1] = nFileLength; Lj 8<'"U#  
} w^;DG
   
} r"]'`qP,  
ja T$gAx  
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//启动子线程 7%d8D>uw8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; n-afDV  
for(int i=0;i<nStartPos.length;i++) OW5t[~y]  
{ VmvQvQ/9R  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `;%ZN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), yyP-=Lhmo=  
nStartPos,nEndPos,i); b?VV'{4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D>#l-{d  
fileSplitterFetch.start(); vg\/Db
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} 9- )qZ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jRQ+2@n{E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); qx)?buAij  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",
ALT^8c&K  
nEndPos = " + nFileLength); &|o$=Ad  
// fileSplitterFetch[nPos.length-1].start(); d7Ro}>lp  
?6N3tk-2  
GDhM<bVqM*  
//等待子线程结束 `8g7q 5  
//int count = 0; 5ukp^OxE  
//是否结束while循环 ;_"U "?h_J  
boolean breakWhile = false; S2^>6/[xM  
{{{#?~3$7  
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while(!bStop) (-^bj  
{ xvm5  
write_nPos(); Gt-UJ-RR y  
Utility.sleep(500); &t}?2>:  
breakWhile = true; M {a #  
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for(int i=0;i<nStartPos.length;i++) M0'v&g  
{ SaDA`JmO  
if(!fileSplitterFetch.bDownOver) T3,1m=S  
{ "Ij
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breakWhile = false; c:4P%({  
break; TkRP3_b  
} [~mGsXV  
} |D#2GeBw1h  
if(breakWhile) 2YBIWR8z  
break; &xd.Qi2  
6d|q+]x_n  
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//count++; !DXNo(:r  
//if(count>4) HEF?mD3h  
// siteStop(); .qD@ Y3-  
} /DFV$+9  
<PD?f/4 /  
/n5n )P@L  
System.err.println("文件下载结束！"); DVp5hR_$  
} 5f7zk  
catch(Exception e){e.printStackTrace ();} 6^F'|Wh  
} >)nS2bOE  
0D&>Gyc*0  

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//获得文件长度 eVz#7vqv  
public long getFileSize() HIc a nk  
{ |zsbW9 W*m  
int nFileLength = -1; ~}9PuYaD@  
try{ MmoR~~*  
URL url = new URL(siteInfoBean.getSSiteURL()); 6z,Dyy]tl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); GHc/Zc"iX  
httpConnection.setRequestProperty("User-Agent","NetFox"); @tT-JwU  
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int responseCode=httpConnection.getResponseCode(); |`O5Xs1{B  
if(responseCode>=400) .IrNa>J
~  
{ ;iQEkn2T|}  
processErrorCode(responseCode); z%d#@w0X1  
return -2; //-2 represent access is error ^_5|BT@  
} :<S<f%  
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|CD"*[j]  
String sHeader; b'p4wE>  
s4LO&STh{  
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for(int i=1;;i++) @E9" Zv-$  
{ ;@mRo`D`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -.I4-6~  
//Utility.log(in.readLine()); v({N:ya  
sHeader=httpConnection.getHeaderFieldKey(i); N;sm*+r  
if(sHeader!=null) LO%!Z,}   
{ cWAtju?L;  
if(sHeader.equals("Content-Length")) |}&RXD  
{ aEVsU|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &p(0K4:  
break; *s4\\Wb=  
} =6 r:A<F!n  
} Do7=#|bAM  
else Fzq41jiS  
break; _ Y2 U7W  
} #E7AmmqD%  
} |+,[``d>"  
catch(IOException e){e.printStackTrace ();} zU5Hb2a  
catch(Exception e){e.printStackTrace ();} k\)Cw  
"h"NW[R  
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Utility.log(nFileLength);  \[:/CxP  
<
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return nFileLength; =^DLywAh}u  
} T? ,P*l  
Cr ?4Ngw  
l1=JrpCan  
//保存下载信息（文件指针位置） m#e3%150{  
private void write_nPos() ,YYVj{~2  
{ s,]%dG!  
try{ @p=
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output = new DataOutputStream(new FileOutputStream(tmpFile)); J%C#V}z7E  
output.writeInt(nStartPos.length); *>8ce-PV  
for(int i=0;i<nStartPos.length;i++) dP2irC%f8  
{ )~)*=u/  
// output.writeLong(nPos); `YBkF  
output.writeLong(fileSplitterFetch.nStartPos); #uCB)n&.  
output.writeLong(fileSplitterFetch.nEndPos); ecJ6  
} vdDludEv  
output.close(); * *H&+T/B  
} fnKY1y]2+  
catch(IOException e){e.printStackTrace ();} Z"-L[2E/{!  
catch(Exception e){e.printStackTrace ();} ~X(UcZ2  
} t(!r8!c u}  
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//读取保存的下载信息（文件指针位置） VZn=rw  
private void read_nPos() I751t  
{ I`(l*U  
try{ qml2XJ>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); T'-FV  
int nCount = input.readInt(); +k<w!B*  
nStartPos = new long[nCount]; P,S G.EFK  
nEndPos = new long[nCount]; EpJ4`{4  
for(int i=0;i<nStartPos.length;i++) /Dtd#OAdr  
{ zLw{ {|  
nStartPos = input.readLong(); :wqC8&V  
nEndPos = input.readLong(); r,P1^uHx  
} b^c9po  
input.close();  _?voU  
} '|>9C^E9X  
catch(IOException e){e.printStackTrace ();} [k$*4u>  
catch(Exception e){e.printStackTrace ();} 9i5,2~  
} 3Ug  
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private void processErrorCode(int nErrorCode) lS^(&<{  
{ |WryBzZ>on  
System.err.println("Error Code : " + nErrorCode); /Ss7"*JLe  
} RR;AJ8wd  
w9RS)l2FQ  
s^OO^%b  
//停止文件下载 |H}m4-+*  
public void siteStop() sd#|3  
{ }V;+l8  
bStop = true; 4F3x@H'  
for(int i=0;i<nStartPos.length;i++) wu9=N ^x  
fileSplitterFetch.splitterStop(); I:V0Xxz5t  
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} )QagS.L{z  
} Si9Z>MR  
//负责部分文件的抓取 6C4'BCYW(  
**FileSplitterFetch.java hd V1nS$  
*/ NCqo@vE  
package NetFox; oY~ Dg  
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|]Z:&[D]i  
import java.io.*; /"H`.LD.?  
import java.net.*; R1:k23{  
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public class FileSplitterFetch extends Thread { o'~5pS(wq  
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String sURL; //File URL o`zr>  
long nStartPos; //File Snippet Start Position O|A_PyW  
long nEndPos; //File Snippet End Position ?;YC'bF  
int nThreadID; //Thread's ID AB Xl  
boolean bDownOver = false; //Downing is over y|&}.~U[  
boolean bStop = false; //Stop identical *rZ^^`4R  
FileAccessI fileAccessI = null; //File Access interface iGDLZE+
?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException R8L_J6Kpa  
{ !{n<K:x1  
this.sURL = sURL;
.O*bILU  
this.nStartPos = nStart; j#~Jxv%n  
this.nEndPos = nEnd; N!Qg;(  
nThreadID = id; &AuF]VT  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~m1P_`T  
} 5Ft5@UF~  
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public void run() rV({4cIe9R  
{ 
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while(nStartPos < nEndPos && !bStop) Z34Wbun4  
{ @ DZD  
2Nxm@B` {  
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try{ S.B<pjgt  
URL url = new URL(sURL); M@P1,Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vQF vtwd  
httpConnection.setRequestProperty("User-Agent","NetFox"); zL5d0_E9  
String sProperty = "bytes="+nStartPos+"-"; &bgvy'p  
httpConnection.setRequestProperty("RANGE",sProperty); v{i7h|e  
Utility.log(sProperty); 5!C_X5M  
7@.cOB`y@3  
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InputStream input = httpConnection.getInputStream(); H4OhIxK  
//logResponseHead(httpConnection); SxyONp.$\  
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byte[] b = new byte[1024]; iDl;!b&V.  
int nRead; =5D nR  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) E6Rz@"^XV  
{ <J(sR  
nStartPos += fileAccessI.write(b,0,nRead); 'B83m#HR#  
//if(nThreadID == 1) 3:"]Rn([P  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #tt?!\8C  
} TGuiNobD  
VhT= l  
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Utility.log("Thread " + nThreadID + " is over!"); >$gG/WD?KR  
bDownOver = true; J" j.'.  
//nPos = fileAccessI.write (b,0,nRead); pqvOJ#?Q}=  
} :ztr)  
catch(Exception e){e.printStackTrace ();} B)$c|dUV  
} . .QB~  
} 0s#vwK13  
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//打印回应的头信息 0Q"u#V Sp  
public void logResponseHead(HttpURLConnection con) U,/6;}  
{ :J}t&t  
for(int i=1;;i++) \&V0vN1  
{ -]C

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String header=con.getHeaderFieldKey(i); Xf=XBoN|  
if(header!=null) h9$ Fx  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0Q1FL MLV  
Utility.log(header+" : "+con.getHeaderField(header)); s"=6{EVqk3  
else k<w(i k1bi  
break; f0+2t.tj  
} z^o1GY  
} Gy1xG.yM~  
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public void splitterStop() "%WgT2)m.  
{ w&Dv8Wv+Oq  
bStop = true; @J[6,$UVu  
}  R7oj#  
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} P7r'ffA  
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/* ,F+B Wot4  
**FileAccess.java h*0S$p<[1  
*//文件访问(定位，写) |6biq8|$3V  
package NetFox; >1L=,M  
import java.io.*; k1z$e*u&r  
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public class FileAccessI implements Serializable{ fbrp#G71y  
TGT$ >/w >  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 maMHZ\Q  
RandomAccessFile oSavedFile; z^* '@  
long nPos; qOCJTOg7  
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public FileAccessI() throws IOException
rt]S\  
{ 78#!Q.#
#  
this("",0); ~ <0Z>qr  
} 6,Hqb<(  
Rz%e>)  
9V1cdb~?"T  
public FileAccessI(String sName,long nPos) throws IOException ,cTgR78'  
{ Ar9nBJ`  
oSavedFile = new RandomAccessFile(sName,"rw"); uE_c4Hp  
this.nPos = nPos; `T*U]/zQ  
oSavedFile.seek(nPos); 4C_c\;d  
} =Cf]  
&!.HuRiuC  
<T,
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public synchronized int write(byte[] b,int nStart,int nLen) suJ_nb  
{ 6y+b5-{'  
int n = -1; `hh9"Ws%  
try{ $FM' 3%B[  
oSavedFile.write(b,nStart,nLen); e&Y0}oY  
n = nLen; BW[5o3 i  
} OTvROJP  
catch(IOException e) 6o3T;h  
{ JXQPT  
e.printStackTrace (); #~Q=h`9  
} sPYX~G&T  
g9tu%cIkR  
+`en{$%%  
return n; ^i%A7pg  
} oVkq2  
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} S0w> hr  
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Rc$h{0K8  
/* e=f.y<  
**SiteInfoBean.java i s"vekC  
*/ ma8wmQ9JR  
package NetFox; :xeLt;  
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y%(X+E"n*  
public class SiteInfoBean { n[k1np$7?6  
<&#+E%E4  
"e62/Ejg%  
private String sSiteURL; //Site's URL ;b~~s.+  
private String sFilePath; //Saved File's Path +cg {[f,J;  
private String sFileName; //Saved File's Name b]
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private int nSplitter; //Count of Splited Downloading File U{1z;lJ  
$C_M&O}  
=&U`9qN  
public SiteInfoBean() hw,^G5m  
{//nSplitter的缺省值为5 SE`l(-tL  
//default value of nSplitter is 5 YB!!/ SX4  
this("","","",5); 2_pz3<,\  
} =Sxol>?t  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) RsSXhPk?  
{ 'V!kL, 9ES  
sSiteURL= sURL; it}-^3AM  
sFilePath = sPath; &4kM8Qh  
sFileName = sName; X%4h(7;v  
this.nSplitter = nSpiltter; kL7^$  
Fj=NiZ=  
4;<DJ.XlN=  
} Yo2Trh  
Q=+8/b  
-<oZ)OfU  
public String getSSiteURL() DP>mNE  
{ c4|so=  
return sSiteURL; &BgU:R,  
} 4 X`^{~  
-CU,z|g+  
oh&Y<d0  
public void setSSiteURL(String value) ,L%p
  
{ (!n-Age  
sSiteURL = value; `Cj,HI_/*  
} wItzcY1m  
ay[+2"  
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public String getSFilePath() C4_t_N  
{ "k
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return sFilePath; iEhDaC[e(b  
} 2u&c &G  
)6G+tU'  
E& ]_U$  
public void setSFilePath(String value) Q-Y@)Mf~?0  
{ [+DNM 2A  
sFilePath = value; Mcb<[~m  
} '%Dg{ zL  
@7|)RSBQz  
+~:0Dxv W  
public String getSFileName() EG1x  
{ g.&\6^)8p  
return sFileName; ddMM74  
} o}R|tOe  
fiqj;GW  
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public void setSFileName(String value) =0Y'f](2eW  
{ 0C7"3l  
sFileName = value; m2MPWy5s  
} g[<uwknf  
V,'FlU  
cFxSDTR  
public int getNSplitter() e)og4  
{ @f'AWeJ2  
return nSplitter; Q,TaJ]  
} {8i}Ow  
Xa\]ua_  
a!{hC)d*  
public void setNSplitter(int nCount) A'(k Yc  
{ h@/>?Va  
nSplitter = nCount; ^)'||Ly  
} n]Ebwznt-  
} n%Rjt!9  
1 pYsjo~  
~M(pCSJ[  
/* $o::PDQ?  
**Utility.java N}1-2  
*/ j[BgP\&,  
package NetFox; l9,w>]s  
r6/<&
1[  
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public class Utility { 0c{Gr 0[>  
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public Utility() ;vZ*,q6  
{ yA457'R1  
I[vM
E"  
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} + >Fv*lux  
l %]<-  
//线程睡眠 _qdWQFuM  
public static void sleep(int nSecond) r{c5dQ  
{ zbdOCfA;  
try{ (u$!\fE-et  
Thread.sleep(nSecond); ggzAU6J  
} Gf!t< =T   
catch(Exception e) 4{uJ||!  
{ +lW+H12  
e.printStackTrace (); \
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} qsQ]M^@>  
} _q2`m  
* N2#{eF&]  
//日志 QLxXp
 
public static void log(String sMsg) 8Fyc#Xo8  
{ noWRYS%  
System.err.println(sMsg); m3x!*9h  
} 0fEZD$  
<5C=i:6%  
w/)e2CH  
public static void log(int sMsg) f4qS OVv
 
{ lU
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System.err.println(sMsg); .CB"@.7  
} ixoMccU0  
} d{(s-  
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F=P+;%.  
/* 0$Qn
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**TestMethod.java ([z<TS#Md  
*/ c9>8IW  
package NetFox; m&;zLBA;  
2\kC_o97  
6ba2^3GH  
public class TestMethod { OoA5!HEh  
"1=.5:y
G  

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public TestMethod() \ZmFH8=|f  
{ ///xx/weblogic60b2_win.exe NG4eEnic!a  
try{ mUe@Dud  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ZKiL-^dob  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); QmDhZ04f  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `:B  
fileFetch.start(); ]y$V/Ij=qK  
} B[2h   
catch(Exception e){e.printStackTrace ();} Oa3=+_C~$1  
.jrR4@  
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} UlLM<33_)  
>V ]*mS%K  
LmT[N@>"  
public static void main(String[] args) Z1qATXXf  
{ A(_^_p.|  
new TestMethod(); vb80J<4  
} ^`B##9g~  
} !EyGJa[i  
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