http断点续传简单实现（java)

/* ?<?C*W_  
**SiteFileFetch.java \Sby(l  
*/ W~F/ZrT3A  
package NetFox; UK>=y_FYO  
import java.io.*; N^]>R:Stu  
import java.net.*; 4Jr[8P0/A9  
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/&d`c=nH  
public class SiteFileFetch extends Thread { sri#L+I  
#6jwCEo=V  
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SiteInfoBean siteInfoBean = null; //文件信息Bean _0["J:s9  
long[] nStartPos; //开始位置 :"^< aLj  
long[] nEndPos; //结束位置 PL$F;d  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 UMwMXmZNJ  
long nFileLength; //文件长度 ~ p.W*skD  
boolean bFirst = true; //是否第一次取文件 +fQL~0tA  
boolean bStop = false; //停止标志 Sc$wR{W<:
 
File tmpFile; //文件下载的临时信息 DB%AO:8  
DataOutputStream output; //输出到文件的输出流 +i#sS19h  
'?gIcWM  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 8ysK VF  
public SiteFileFetch(SiteInfoBean bean) throws IOException eJGos!>*  
{ jgKL88J*\  
siteInfoBean = bean; TDE1z>h+"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X&?lDL7?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); T\!SA  
if(tmpFile.exists ()) r_,m\'~s!  
{ F6c[v|
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bFirst = false; /_OZ1jX  
read_nPos(); d 4\E  
} Pd "mb~  
else d"6]?  
{ tW:/R@@  
nStartPos = new long[bean.getNSplitter()]; _L'cyH.cn  
nEndPos = new long[bean.getNSplitter()]; ;u};&sm  
} E9B*K2l^{  
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4  
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} AJ
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public void run() AOx3QgC^NO  
{ FT/5 _1i  
//获得文件长度 JX/4=..  
//分割文件 _#D\*0J  
//实例FileSplitterFetch d<Q+D1  
//启动FileSplitterFetch线程 iynS4
]`U  
//等待子线程返回 tP Efz+1N  
try{ hJo^Wo  
if(bFirst) Y-3[KHD  
{ L^Q+Q)zTh  
nFileLength = getFileSize(); ,Q=)$ `%  
if(nFileLength == -1) #f3;}1(  
{ K

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System.err.println("File Length is not known!"); Mev-M2A  
} Rs F3#H  
else if(nFileLength == -2) G(OT"+O,  
{ nN`Z0?  
System.err.println("File is not access!"); QYTTP6 Gz+  
} yEUNkZ5^  
else PWk?8dL-  
{ .)@tXH=}+  
for(int i=0;i<nStartPos.length;i++) n*m"L|:ff  
{ }K/}(zuy1Y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); TjUZv1(L  
} .5!sOOs$P  
for(int i=0;i<nEndPos.length-1;i++) %-ZR~*  
{ mbX)'. +L  
nEndPos = nStartPos[i+1]; E/7vIg F  
} qbU1qF/  
nEndPos[nEndPos.length-1] = nFileLength; j[/SXF\=  
} ~njbLUB  
} qHR^0&  
C
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RZ|HwYG  
//启动子线程 g{v5mly  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `  -[Bo  
for(int i=0;i<nStartPos.length;i++) rO(TG  
{ c BHL,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '9 *|N=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &:DCtjK  
nStartPos,nEndPos,i); y*}vG}e%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); DN"S,  
fileSplitterFetch.start(); (K*/Vp  
} &e ?"5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UbY~xs7_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); f3zfRhkIk  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", c}IX"  
nEndPos = " + nFileLength); Tr+h$M1_Ja  
// fileSplitterFetch[nPos.length-1].start(); S!jF:Uc
 
5 dfe@$  
N[,VSO&  
//等待子线程结束 :kb1}Wu  
//int count = 0; 8<yV  
//是否结束while循环 X;OsH  
boolean breakWhile = false; ]g>m?\'n  
<+T\F;   
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while(!bStop) 0q[p{_t`  
{ N)y^</Ya  
write_nPos(); ~m?74^ i  
Utility.sleep(500); b(#"
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breakWhile = true; YN%=Oq  
j<ABO")v  
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for(int i=0;i<nStartPos.length;i++) s;B j7]  
{ ?qg^WDs$  
if(!fileSplitterFetch.bDownOver) bkr~13S{+  
{ T_
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breakWhile = false; p.rdSv(8'  
break; mUrS&&fu8  
} ?w]"~   
} A6^p}_  
if(breakWhile) j-lSFTo  
break; V3>f*Z)xn  
q_<*esZ,  
a^*cZ?Ta  
//count++; MkG`w,  
//if(count>4) k9}Q7)@  
// siteStop(); {{V;:+62  
} });cX$  
/h}PEu3y  
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System.err.println("文件下载结束！"); pqyWv;  
} E-UB -"6  
catch(Exception e){e.printStackTrace ();} xm<v"><  
} l|08  
(NH8AS<  
@-'/__cgt  
//获得文件长度 9J~:m$.  
public long getFileSize() K1?Z5X(b  
{ E4sn[DO  
int nFileLength = -1; <|{L
[  
try{ pN\)(:"8v  
URL url = new URL(siteInfoBean.getSSiteURL()); 9W{,=.%MX$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); RLdlz  
|av*!i5Q  
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int responseCode=httpConnection.getResponseCode();
&$mZ?%^C  
if(responseCode>=400) m b%C}8D  
{ W(;x\Nc7  
processErrorCode(responseCode); $|4cJ#;^L  
return -2; //-2 represent access is error !oZQ2z~  
} |-~b$nUe  
0LetsDN7I  
K :1g"  
String sHeader; /xl4ohL$a  
.)LZ`Ge3F  
9{_8cpm4  
for(int i=1;;i++) b;S6'7Jf9  
{ }1QI"M*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); fNmE,~
 
//Utility.log(in.readLine()); S5uJX#*;  
sHeader=httpConnection.getHeaderFieldKey(i); H_VEPp,T  
if(sHeader!=null) Yo>`h2C4  
{ x&at^Fp  
if(sHeader.equals("Content-Length")) )
.pO2lLF4  
{ /8f>':zUb  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); r?fH &u  
break; h/,R{A2mO  
} xDR9_  
} 60xa?8<cg  
else iV5}U2Vh  
break; sW }<zGYd  
} 5\okU"{d7  
} V?OuIg%=:  
catch(IOException e){e.printStackTrace ();} :1:3Svb<Y  
catch(Exception e){e.printStackTrace ();} q_cC7p6t  
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_b>F#nD,'%  
Utility.log(nFileLength); ):e+dt  
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return nFileLength; ? m&IF<b  
} :.Y|I[\E%  
dVa!.q_3  
O/mR9[}  
//保存下载信息（文件指针位置） F"!agc2!  
private void write_nPos() \Ke8W,)ew  
{ 1Fv8T'  
try{ TYYp"wx  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2b5#PcKa  
output.writeInt(nStartPos.length); +a|"{  
for(int i=0;i<nStartPos.length;i++) zJ5hvDmC  
{ X4a^mw\"  
// output.writeLong(nPos); }i(qt&U;  
output.writeLong(fileSplitterFetch.nStartPos); 5?Bc Y;  
output.writeLong(fileSplitterFetch.nEndPos); ! 0^;;'  
} fV 3r|Bp  
output.close(); 3filAGR?  
} )CJES!! W  
catch(IOException e){e.printStackTrace ();} M&r2:Whk  
catch(Exception e){e.printStackTrace ();} 1Q]Rd  
} |+98h&U~  
cgyp5\*>+  
K4C^m|e  
//读取保存的下载信息（文件指针位置） |pJC:woq  
private void read_nPos() ',GV6kt_k  
{ o7.e'1@  
try{ sI'a1$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); q
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int nCount = input.readInt(); u#1%P5r&X  
nStartPos = new long[nCount]; ]Kv q
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nEndPos = new long[nCount]; q(78fZ *X  
for(int i=0;i<nStartPos.length;i++) 3QW_k5o  
{ |XRI
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nStartPos = input.readLong(); v,{h:  
nEndPos = input.readLong(); KF_?'X0=  
} %`e`g ^  
input.close(); +td<{4oq8  
} F+m[&MKL  
catch(IOException e){e.printStackTrace ();} b(l0js  
catch(Exception e){e.printStackTrace ();} n@hl2M6.x9  
} >L gVj$Z  
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} ~| k  
private void processErrorCode(int nErrorCode) ^-hErsK  
{ [>f]@>  
System.err.println("Error Code : " + nErrorCode); /prYSRn8  
} <?YA,"~  
9t?L\
  
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//停止文件下载 `?"6l5d.]  
public void siteStop() B8H75sz  
{ k^%2_H  
bStop = true; >.e+S?o  
for(int i=0;i<nStartPos.length;i++) \7Qb229?  
fileSplitterFetch.splitterStop(); 8u>gbdU  
y%S})9  
" !-Kd'V  
} h./P\eDc  
} wO7t!35  
//负责部分文件的抓取 4/'N|c.  
**FileSplitterFetch.java :'}@Al9=>  
*/ 9C/MRmv`  
package NetFox; hd2'AlB  
yzR=A%V8A  
id?"PD"%  
import java.io.*; _7"5wB?|+  
import java.net.*; uFG<UF  
>zs5s
  
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public class FileSplitterFetch extends Thread { F}36IM9/:  
?qmp_2:WU  
c7K!cfO:{N  
String sURL; //File URL C5*xQlCq}  
long nStartPos; //File Snippet Start Position (RE2I  
long nEndPos; //File Snippet End Position _w!a`w*3  
int nThreadID; //Thread's ID w<NyV8-hL  
boolean bDownOver = false; //Downing is over .Q* 'r&n  
boolean bStop = false; //Stop identical BMFF=  
FileAccessI fileAccessI = null; //File Access interface BI/&dKM  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $SY]fNJQ  
{ Elb aFbr  
this.sURL = sURL; ^zr^ N?a  
this.nStartPos = nStart; jVWK0Zba  
this.nEndPos = nEnd; 3^,QIG  
nThreadID = id; 5MF#&v  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2S~R!   
} |(%zb\#9  
8e&p\%1  
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public void run() 3n]79+w@z  
{ w0lT%CPx  
while(nStartPos < nEndPos && !bStop) wTc)S6%7  
{ 56}X/u  
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try{ *O~e T  
URL url = new URL(sURL); W7sn+g\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `3cCH  
httpConnection.setRequestProperty("User-Agent","NetFox"); "i^ GmVn  
String sProperty = "bytes="+nStartPos+"-"; 6%Mt  
httpConnection.setRequestProperty("RANGE",sProperty); <vV_%uoM  
Utility.log(sProperty); K.~q+IYP[  
!l@zT}i??  
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InputStream input = httpConnection.getInputStream(); 9+=gke  
//logResponseHead(httpConnection); u]*0;-tz  
% Zjdl  
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byte[] b = new byte[1024]; d+eZub94U  
int nRead; }UwO<#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) tc+WWDP#"
 
{ sD;M!K_  
nStartPos += fileAccessI.write(b,0,nRead); a_~=#]a  
//if(nThreadID == 1) k[j90C5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zUJZ`seF  
} <
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p>w]rE:}  
Q\ppfc{,  
Utility.log("Thread " + nThreadID + " is over!"); OHv!  
bDownOver = true; <ABX0U[*  
//nPos = fileAccessI.write (b,0,nRead); Ifc]K?  
} saf&dd  
catch(Exception e){e.printStackTrace ();} Fh$slow4!  
} yLE7>48  
} g4p  
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SRIA*M.B}  
//打印回应的头信息 ypOLp SYk  
public void logResponseHead(HttpURLConnection con) yw-8#y  
{ r!1D*v5&:  
for(int i=1;;i++) %EbPI)yY3  
{ ~^jq(:d)  
String header=con.getHeaderFieldKey(i); CNZz]H  
if(header!=null) Q4*?1`IsR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ElhRF{R  
Utility.log(header+" : "+con.getHeaderField(header)); !>
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else "hxN!,DEZ  
break; HBS\<}  
} m,i,n9C->  
} pKiZ)3U  
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public void splitterStop() s#~GH6/  
{ 8BOZh6BV  
bStop = true; ,l YE  
} W!Hm~9fz  
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} &Mq~T_S  
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/* ULrr=5&8  
**FileAccess.java V&8VwF^-  
*//文件访问(定位，写) klg2
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package NetFox; gxz-R?.  
import java.io.*; m7a#qs;,  
hI%bjuq  
3~S'LxV  
public class FileAccessI implements Serializable{ Unj.f>U  
voP7"Dl[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 wN1niR'  
RandomAccessFile oSavedFile; %VYAd)gC  
long nPos; x-OA([;/  
f=C,e/sw  
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public FileAccessI() throws IOException wO ?+Nh  
{ _vSn`  
this("",0); drzL.@h|  
} :I -V_4b  
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public FileAccessI(String sName,long nPos) throws IOException -p3Re9  
{ Bjk]ZU0T  
oSavedFile = new RandomAccessFile(sName,"rw"); O5$/55PI  
this.nPos = nPos; 7K)6^r^  
oSavedFile.seek(nPos); yjfat&$  
} bM8If"  
~U;rw&'H  
S
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public synchronized int write(byte[] b,int nStart,int nLen) IDnC<MO>  
{ 'smWLz}  
int n = -1; 8} =JKR^cK  
try{ nF6q7  
oSavedFile.write(b,nStart,nLen); PH"n{lW.T  
n = nLen; 5>BK%`  
} >2bK
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catch(IOException e) PV|uPuz  
{ ^Ge+~o?x  
e.printStackTrace (); j'9"cE5_  
} i4^o59}8  
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return n; LPMU8Er  
} Fx-8M
!  
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} ^i:`ZfA#
 
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5:'hj$~|\1  
/* z9aY]lHY  
**SiteInfoBean.java K~@Mg1R  
*/ '1M7M(va  
package NetFox; 0eK*9S]  
W 4F\}A  
|V<h=D5W  
public class SiteInfoBean { 035rPT7-2-  
v|U(+O  
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private String sSiteURL; //Site's URL rn<PR*  
private String sFilePath; //Saved File's Path #1>X58I^  
private String sFileName; //Saved File's Name @)Ofi j  
private int nSplitter; //Count of Splited Downloading File }Ho Qwy|&  
>JiltF7H0  
sQMFpIrr  
public SiteInfoBean() DGzw8|/(  
{//nSplitter的缺省值为5 m!<\WN6g  
//default value of nSplitter is 5 [B+W%g(c-  
this("","","",5); mEG#>Gg$  
} 4~B> 9<$e>  
NH+(?TN  
27;ci:5  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) J~#;<e{\"  
{ &^W|iXi
#  
sSiteURL= sURL; I1PuHf Qs  
sFilePath = sPath; =}.EY iD  
sFileName = sName; m9/}~Y#k  
this.nSplitter = nSpiltter; 4'0Dr++  
qK)73eNSR  
DZi!aJ  
} o865(<p  
5}`_x+$%(`  
M)U{7c$c7  
public String getSSiteURL() dPhQ :sd>  
{ -|E!e.^7:  
return sSiteURL; OoWyPdC+P  
} .k,kTr$S  
)I3NeKWz  
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public void setSSiteURL(String value) EVoEszR  
{ TYy.jFT-  
sSiteURL = value; V{JAB]?^  
} 6L)%T02C  
-;'1^  
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public String getSFilePath() gvLf|+m  
{ nw-I|PVTNa  
return sFilePath; P>Ez'C  
} J>\B`E  
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public void setSFilePath(String value) p\bDY  
{ ~$~5qwl  
sFilePath = value; p\<u6v ~J  
} %"P,1&\^  
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public String getSFileName() |9B.mBoX  
{ t2lS ~l)  
return sFileName; <WcR,d  
} >"C,@cN}B  
(vTtDKp@  
R=|{n'n$0|  
public void setSFileName(String value) ndkti5L,   
{ Cvf[/C+  
sFileName = value; B#M5}QT|2  
} u,UmrR  
|]c8jG\h  
DK$s&zf  
public int getNSplitter() $fzaPD4.  
{ f\jLqZY  
return nSplitter; G%s2P.cd  
} xftBSdVE  
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h  
]bK=FIK2  
public void setNSplitter(int nCount) 9pX&ZjYP-  
{ T87m?a$  
nSplitter = nCount; 8p:j&F  
} g4l
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} /bi}'H+#  
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/* %oO4|JkJX  
**Utility.java 7:2WgLo  
*/ F~P%AjAx'  
package NetFox; w$Rro)?}7  
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NB8/g0:=n&  
public class Utility { (,8$V\  
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public Utility() 4B^ZnFJ%m  
{ } x2DT8u  
fc |GArL#}  
@g&ct>@y  
} _iir<}  
zlEX+=3  
//线程睡眠 +w+}b^4  
public static void sleep(int nSecond) r_-_a(1R:  
{  {PVWD7  
try{ 4/wa+Y+=vt  
Thread.sleep(nSecond); ,d{"m)r<  
} iy%ZQ[Un  
catch(Exception e) IkGfnXJ  
{ `a2n:F  
e.printStackTrace (); J{k79v  
}
-$dXE+&   
} ])nPPf  
6BCf:mqP  
//日志 )s%[T-uKi  
public static void log(String sMsg) o}* hY"&  
{ MpF$xzh  
System.err.println(sMsg); ;JayoJ  
} FgB&b  
l=v4Fa0^jF  
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public static void log(int sMsg) U15H@h  
{ uLWh|
  
System.err.println(sMsg); E(Z8  
} mD^jd+  
} D?NbW @]  
#6CC3TJ'k  
/N&CaH\;^$  
/* a+%6B_|\  
**TestMethod.java :(M(>4t  
*/ ybY]e; v*O  
package NetFox; ZOZ+Y\uU  
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public class TestMethod { [O?z@)dx  
5nKj )RH7M  
R5X.^u  
public TestMethod() %3ICI  
{ ///xx/weblogic60b2_win.exe 1f":HnLRM  
try{ ]hFW73FV  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }#&#^ B#?O  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TztAZ2C  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @n{JM7ctJ  
fileFetch.start(); [E/\#4b  
} N-e @j4WU  
catch(Exception e){e.printStackTrace ();} [<  &oF  
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yrC7F`.  
} Y07ZB'K  
!'cl"\h  
5'X ]k@m_  
public static void main(String[] args) @T'i/}nl  
{ P_Gw-`L5T  
new TestMethod(); (q(~de  
} -UOj>{-  
} /Sc l#4bW  
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