http断点续传简单实现（java)

/* DECB*9O^  
**SiteFileFetch.java ks*Y9D*=  
*/ q*,Q5  
package NetFox; u)a'  
import java.io.*; )P?IqSEA%  
import java.net.*; re^Hc(8M  
!^e =P%S  
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public class SiteFileFetch extends Thread { _T5)n=|  
 B/G-Yh$E  
SRZL\m}  
SiteInfoBean siteInfoBean = null; //文件信息Bean 5u r)uz]w8  
long[] nStartPos; //开始位置 UZGDdP  
long[] nEndPos; //结束位置 ]ab#q=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 XM/vDdR  
long nFileLength; //文件长度 mk!Dozb/  
boolean bFirst = true; //是否第一次取文件 lT'9u,6  
boolean bStop = false; //停止标志 T dk ,&8  
File tmpFile; //文件下载的临时信息 5{K}?*3hJ  
DataOutputStream output; //输出到文件的输出流 a8pY[)^c  
](#&.q%5!  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }s_hD`'  
public SiteFileFetch(SiteInfoBean bean) throws IOException [84F09HU  
{ =>|C~@C?  
siteInfoBean = bean; PFM'&;V  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (&[[46  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +H_MV=A^  
if(tmpFile.exists ()) "7,FXTa
er  
{ d-
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bFirst = false; nPN?kO=]  
read_nPos();
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} Y
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else )}MHx`KT2  
{ WA6!+Gy  
nStartPos = new long[bean.getNSplitter()]; wJeG(h  
nEndPos = new long[bean.getNSplitter()]; hIYTe  
} }^-<k0A4?  
8 TiG3  
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} \,&9  
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public void run() geM6G$V&  
{ RO&H5m r%@  
//获得文件长度 -r<#rITH"  
//分割文件 4-R^
/A0  
//实例FileSplitterFetch 8z2Rry w  
//启动FileSplitterFetch线程 CSTI?A"P  
//等待子线程返回 Nc)J18  
try{ 6GAaV[])'  
if(bFirst) usFfMF X  
{ F%d\~Vj  
nFileLength = getFileSize(); .fYZ*=P;c  
if(nFileLength == -1) F'JY?  
{ eq[Et +  
System.err.println("File Length is not known!"); &QNY,Pj  
} O(z}H}Fv  
else if(nFileLength == -2) cXnKCzSxZq  
{ #!2k<Q*5uT  
System.err.println("File is not access!"); G8Z4J7^  
} -nbMTY}  
else Km#pX1]>e  
{ 4)6xU4eBaL  
for(int i=0;i<nStartPos.length;i++) _[K"gu  
{ ,=QM#l]  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); b'YE9E  
} 8RW&r  
for(int i=0;i<nEndPos.length-1;i++) V\]" }V)"  
{ 0aI;\D*Ts  
nEndPos = nStartPos[i+1]; /) 4GSC}Gg  
} 1f'Hif*r_X  
nEndPos[nEndPos.length-1] = nFileLength; Wg`AZ=t  
} `J0i.0p  
} ^|!I+  
6w[}&pX"z  
j*v40mXl`2  
//启动子线程 V9wI\0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; m#vL*]c}  
for(int i=0;i<nStartPos.length;i++) E Y<8B3y  
{ a
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6K`c/)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `d]IX^;  
nStartPos,nEndPos,i); cO2& VC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H( jXI  
fileSplitterFetch.start(); 4mjgt<`  
} 3REx45M2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DQ#H,\^<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I` K$E/ns  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", O,2~"~kF  
nEndPos = " + nFileLength); i':i_kU  
// fileSplitterFetch[nPos.length-1].start(); gi/@j  
$2^
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+ @9.$6N  
//等待子线程结束 |{r$jZeE  
//int count = 0; j%
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//是否结束while循环 N,dT3we  
boolean breakWhile = false; M 3 '$[  
'_\;jFAM  
$''?HjB
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while(!bStop) }9HmTr|  
{ j(:I7%3&(*  
write_nPos(); h^9"i3H  
Utility.sleep(500); 6VP`evan  
breakWhile = true; %@a8P  
}v9\F-0>Q  
7;@ST`cC  
for(int i=0;i<nStartPos.length;i++) DZ7 gcC  
{
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if(!fileSplitterFetch.bDownOver) $ ,SF@BhO  
{ {GDmVWG0q  
breakWhile = false; ~\)qi=  
break; le+R16Z
 
} 0P^L}VVX  
} ).` S/F  
if(breakWhile) D\w h;r  
break; {rfF'@[  
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Ho DVn/lr  
//count++; u] :m"LM  
//if(count>4) }8|[;Qa`y  
// siteStop(); /={Js*  
} fj7|D'c  
-9
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}G o$ \Bk  
System.err.println("文件下载结束！"); vb 1@yQ  
} Z=B_Ty  
catch(Exception e){e.printStackTrace ();} FGO[ |]7IN  
}
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DFhXx6]  
//获得文件长度 e^4 p%  
public long getFileSize() sDr/k`>  
{ =S'%`]f?  
int nFileLength = -1;  ~>O)  
try{ MV_Srz  
URL url = new URL(siteInfoBean.getSSiteURL()); Zwcy4>8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ES~^M840f  
httpConnection.setRequestProperty("User-Agent","NetFox"); iwz  
HEL!GC>#  
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int responseCode=httpConnection.getResponseCode(); 5D M"0  
if(responseCode>=400) -9RDr\&`(  
{ g%F"l2M  
processErrorCode(responseCode); g(VNy@  
return -2; //-2 represent access is error 0;S,tJg  
} /@AEJ][$  
1Je9,dd6  
/bj <Ft\  
String sHeader; o"wXIHUmV  
M/x>51<  
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for(int i=1;;i++) P%)gO  
{ 5@*'2rO&!  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Hf'G8vW  
//Utility.log(in.readLine()); (~zd6C1.  
sHeader=httpConnection.getHeaderFieldKey(i); K{n{KB&_&  
if(sHeader!=null) m9U"[Huv1E  
{ x21dku<6K[  
if(sHeader.equals("Content-Length")) p!]6ll^  
{ ]yjl~3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9/+Nj/  
break; :o:e,WKxb  
} %WqNiF0-  
} go+Q~NV  
else UobyK3.%  
break; H|cNH=  
} 85EQ5yY  
} ,-x!$VqS  
catch(IOException e){e.printStackTrace ();} OD']:  
catch(Exception e){e.printStackTrace ();} $$:ZX  
$/6;9d^  
2[0JO.K 4  
Utility.log(nFileLength); *:i1Lv@  
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return nFileLength; .jy]8S8[|%  
} yj4+5`|f  
*yl>T^DjTC  
hOhS)  
//保存下载信息（文件指针位置） 7'NwJ,$6\  
private void write_nPos() *6xgctk  
{ cA6lge<{~  
try{ XeBP`\>Ve  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .>z][2oz  
output.writeInt(nStartPos.length); eIl]oC7*  
for(int i=0;i<nStartPos.length;i++) xBu1Ak8w  
{ XZw6Xtn  
// output.writeLong(nPos); JdZ+Hp3.  
output.writeLong(fileSplitterFetch.nStartPos); P0`Mdk371  
output.writeLong(fileSplitterFetch.nEndPos); Y(.OF Q  
} 6<K6Y5<6  
output.close(); 4v[~r1!V  
} g$. \
  
catch(IOException e){e.printStackTrace ();} @( n^T  
catch(Exception e){e.printStackTrace ();} Ltjbxw"Qd  
} =]3tUD  
bc , p}  
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//读取保存的下载信息（文件指针位置） i#%aTRKHd6  
private void read_nPos() G,;,D9jO7  
{ p4p@^@<>X  
try{ wP,JjPUt  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); fDx9iHGv  
int nCount = input.readInt(); Mi~(aah  
nStartPos = new long[nCount]; eT2*W$  
nEndPos = new long[nCount]; qRbf2;  
for(int i=0;i<nStartPos.length;i++) h*u`X>!!  
{ iAa;6mH  
nStartPos = input.readLong(); "`6n6r42  
nEndPos = input.readLong(); (H+'X}1  
} Zo>]rKeV  
input.close(); <AJ97MLcc  
} tGB@$UmfU  
catch(IOException e){e.printStackTrace ();} HHqwq.zIy  
catch(Exception e){e.printStackTrace ();} Gycm,Cy  
} dg4vc][  
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l }XU59  
private void processErrorCode(int nErrorCode) Z$J#|  
{ dL|+d:v  
System.err.println("Error Code : " + nErrorCode); 0a"igq9t  
} !n^OM?.
4  
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//停止文件下载 h
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public void siteStop() >vo=]cw  
{ y\{%\$  
bStop = true; ax 41N25  
for(int i=0;i<nStartPos.length;i++) DNP13wp@  
fileSplitterFetch.splitterStop(); }MUn/ [x  
If%/3UJ@  
Z4IgBn(Z_}  
} #nh|=X  
} 1 hg}(Hix  
//负责部分文件的抓取 :kfp_o+J  
**FileSplitterFetch.java B:7mpSnEQ  
*/ G9JAcO1  
package NetFox; (rg;IXAq%  
)?wJF<[_#  
;2Q~0a|  
import java.io.*; ws^4?O  
import java.net.*; sUE?v9  
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public class FileSplitterFetch extends Thread { ~)(\6^&=|  
vOg#Dqn-  
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String sURL; //File URL "Ky; a?Y  
long nStartPos; //File Snippet Start Position <id}<H  
long nEndPos; //File Snippet End Position 1{P'7IEj  
int nThreadID; //Thread's ID tnLAJ+-M  
boolean bDownOver = false; //Downing is over GRY2?'`  
boolean bStop = false; //Stop identical $/nY5[  
FileAccessI fileAccessI = null; //File Access interface 9uWY@zu  
/> 4"~q)  
0@AAulRl  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `=7j$#6U  
{ ;j2vHU#q-  
this.sURL = sURL; Qyy.IPTP  
this.nStartPos = nStart; kY'T{Sm1^  
this.nEndPos = nEnd; ]5%/3P,/  
nThreadID = id; c_elShK8#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 MTUn3;c/  
} O(_[ayE  
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public void run() ^n+!4(@=  
{ [k-+AA>:  
while(nStartPos < nEndPos && !bStop) >$2V%};  
{ "le>_Ze_>|  
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try{ hdVdcnM  
URL url = new URL(sURL); <jed!x  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a5w:u5  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'MY/*k7:  
String sProperty = "bytes="+nStartPos+"-"; H8"@iE,  
httpConnection.setRequestProperty("RANGE",sProperty); f47M#UC  
Utility.log(sProperty); zhf.NCSt(  
O eL}EVs8=  
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InputStream input = httpConnection.getInputStream(); c*@G_rb  
//logResponseHead(httpConnection); 8n>9;D5n  
im @h -A]0  
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byte[] b = new byte[1024]; /B}lO0]:  
int nRead; q/n,,!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?@V[#.  
{ FHV-BuH5  
nStartPos += fileAccessI.write(b,0,nRead); E4hLtc^ +
 
//if(nThreadID == 1) 5<w g8y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9*a=iL*Nw  
} 6&/T@LQYrh  
R
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-{ZWo:,r~q  
Utility.log("Thread " + nThreadID + " is over!"); 0tU.(  
bDownOver = true; QV\eMuNy  
//nPos = fileAccessI.write (b,0,nRead); QVtQx>K`  
} a1@Y3MQ;i  
catch(Exception e){e.printStackTrace ();} ooQQ-?"m  
} NC38fiH_N  
} 0'IBN}  
73){K?R  
x7$}8LZ"B  
//打印回应的头信息 @9"J|}  
public void logResponseHead(HttpURLConnection con) y:6; LZ9[  
{ _8E/)M  
for(int i=1;;i++) &%-73nYw  
{ N ,z6y5Lu  
String header=con.getHeaderFieldKey(i); >vA2A1WhW  
if(header!=null) G.UI|r/Kz  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gg8Uo G  
Utility.log(header+" : "+con.getHeaderField(header)); ghRVso(  
else F>rH^F  
break; z[;z>8|c  
} R2 V4#  
} Gh}*q|Lz  
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public void splitterStop() Q@HopiC  
{ K1T4cUo  
bStop = true; O<V4HUW  
} ^(FdXGs[  
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} :eCU/BC4  
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/* jB(|";G  
**FileAccess.java 4H/
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*//文件访问(定位，写) GI1  
package NetFox; 5@BBoeG  
import java.io.*; {lc\,F*$  
<.? jc%  
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public class FileAccessI implements Serializable{ d}4Y(   
ZEx}$<)_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Ll4g[8  
RandomAccessFile oSavedFile; 5bgs*.s  
long nPos; - RU=z!{  
)<tI!I][j  
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public FileAccessI() throws IOException a5TioQ  
{ ~5oPpTAe  
this("",0); NN?`"Fww  
} gp\<p-}  
.~7FyLl$  
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public FileAccessI(String sName,long nPos) throws IOException 3(,?S$>  
{ RtM8yar+sn  
oSavedFile = new RandomAccessFile(sName,"rw"); #%h-[/  
this.nPos = nPos; ]'=)2 .}  
oSavedFile.seek(nPos); W}mn}gTQ  
} >: g3k  
R)m'lMi|  
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public synchronized int write(byte[] b,int nStart,int nLen) jJPGrkr  
{ 4.5|2\[  
int n = -1; ~S,,w1`  
try{  #^A*  
oSavedFile.write(b,nStart,nLen); /PSd9N*=y  
n = nLen; }|8_9Rx0*  
} I<6P;  
catch(IOException e) ~G6Ox)/  
{ Vo'T!e- B  
e.printStackTrace (); ][p>Y>:b-  
} *(T:,PY  
/$p6'1P8  
dx@-/^.  
return n; m()RU"WY  
} m0a?LY  
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} `M^= D&Bf  
) iN/ua  
>E{";C)  
/* 7Bd-!$j+  
**SiteInfoBean.java KJaXg;,H  
*/ wMg0>  
package NetFox; 8b;1FQ'  
f@
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public class SiteInfoBean { "ozr+:#\  
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private String sSiteURL; //Site's URL eEv@}1~  
private String sFilePath; //Saved File's Path M:[ %[+6  
private String sFileName; //Saved File's Name _)>_{Pm  
private int nSplitter; //Count of Splited Downloading File naR0@Q"\h  
,N]H dR  
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public SiteInfoBean() NUWDc]@J*  
{//nSplitter的缺省值为5 =k^Y?.  
//default value of nSplitter is 5 NRIG1v>  
this("","","",5); UMm!B`M  
} )9"_J9G  
r\-uJ~8N  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6"J? #  
{ q!u~jI9j  
sSiteURL= sURL; V8C:"UZ;  
sFilePath = sPath; pUQ/03dp  
sFileName = sName; ($;77fPR  
this.nSplitter = nSpiltter; xg;+<iW  
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} Rnr(g;2  
(mTE;s(  
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public String getSSiteURL() $Y/9SV,  
{ 26I_YL,S  
return sSiteURL; RL@VSHXc  
} i%#+\F.&  
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UU;(rS/  
public void setSSiteURL(String value) r")`Ph@yp  
{ K<SyC54  
sSiteURL = value; ( u\._Gwsx  
} 7e|s wJ>4  
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public String getSFilePath() F@'Jbd`   
{ 1Z+8r  
return sFilePath; W14 J],{L  
} 8<pzb}xK  
p6#g;$V$  
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public void setSFilePath(String value) t\~P:"  
{ 6;\I))"[  
sFilePath = value; (a.z9nqGA  
} +eK"-u~K  
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public String getSFileName() [65`$x
-  
{ ~962i#&4  
return sFileName; QkEvw<  
} `1$@|FgyC  
cdl&9-}  
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public void setSFileName(String value) F4}]b(L  
{ Z<1FSk,[  
sFileName = value; -:Da&V  
} |ef7bKU8  
eTI%^d|  

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public int getNSplitter() \r^qL^  
{ Y)0*b5?1r  
return nSplitter; DS.RURzd{r  
} AS'R?aX|C  
1 d}Z(My  
p*4':TFuD;  
public void setNSplitter(int nCount) H]{v;;'~  
{ (C-{B[Y  
nSplitter = nCount; r3&G)g=u  
} y&q*maa[  
} 42{Ew8  
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/* vj'wm}/  
**Utility.java \qdHX  
*/ F\JM\{&F  
package NetFox; :~e>Ob[,"  
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ov`h  
public class Utility { tZ:_ag)o  
^ =bu(L  
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public Utility() *}F3M\  
{ b~KDP+Ri  
\HxT@UQ)~  
`5cKA;j>b  
} ddJQC|xR}  
>kj`7GA  
//线程睡眠 l2zFKCGF(  
public static void sleep(int nSecond) @Owb?(6?  
{ we~[] \  
try{ H*RC@O_hv  
Thread.sleep(nSecond); >Ea8G,  
} ~
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catch(Exception e) 4IB9,?p  
{ p `8s  
e.printStackTrace (); :1cV;gJ  
} A
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} FcR=v0),  
~P*6ozSYpY  
//日志 3m]4=  
public static void log(String sMsg) \8)U!9,$nn  
{ l
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System.err.println(sMsg); Y}t \4 di  
} 1tEgl\u\  
!O+)sbd<  
/[a~3^Gs^  
public static void log(int sMsg) /f:dv?!km  
{ =)M/@T  
System.err.println(sMsg); ^W`<gR  
} oRm L {UDZ  
} 3QV*%  
nHnK)9\N  
$:=A'd2  
/* 7]U"Z*  
**TestMethod.java e}D3d=6`  
*/ K,Ef9c/+K  
package NetFox; hEA<o67  
I?h)OvWd  
!^^?dRd*v  
public class TestMethod { ;;_,~pI?k  
TTeH`  
8;d:-C
p  
public TestMethod() W3]_m8,Z  
{ ///xx/weblogic60b2_win.exe R?GDJ3  
try{ \kp8S'qVo  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6bomh2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); X@$f$=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); j2Cks_$:  
fileFetch.start(); 8|):`u  
} > A Khf  
catch(Exception e){e.printStackTrace ();} )_+rU|We  
<>dT64R|  
.R)D3NZp  
} j|4<i9^}  
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public static void main(String[] args) HFKfkAl  
{ ) brVduB  
new TestMethod(); q4R5<LW"  
} VvvRRP^q  
} 4H,`]B8(D  
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