http断点续传简单实现（java)

/* f"-?%I*'  
**SiteFileFetch.java "
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*/ |?0C9  
package NetFox; g,1\Gj%y  
import java.io.*; Gh< r_O~L3  
import java.net.*; |_A35"v  
rN*4Y  
':fVb3A[*d  
public class SiteFileFetch extends Thread { xo*a9H?@  
"kL5HD]TC  

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SiteInfoBean siteInfoBean = null; //文件信息Bean /
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long[] nStartPos; //开始位置 1,/oS&?E  
long[] nEndPos; //结束位置 4iw+3 Q|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 y
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long nFileLength; //文件长度 i\3
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boolean bFirst = true; //是否第一次取文件 lKa}Bcd  
boolean bStop = false; //停止标志 >97V2W  
File tmpFile; //文件下载的临时信息 `fL$t0"  
DataOutputStream output; //输出到文件的输出流 dtnAMa5$T  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 7y60-6r  
public SiteFileFetch(SiteInfoBean bean) throws IOException t
#d~gBe?V  
{ 6g!t1%Kb  
siteInfoBean = bean; m*(8I=]q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 9\dC8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -Z#A}h  
if(tmpFile.exists ()) }6o` in>M  
{ Bp b_y;E  
bFirst = false; jbG #__#_  
read_nPos(); FkRrW^?5G  
} m7d? SU  
else t<Og?m
}(  
{ ,H|V\\  
nStartPos = new long[bean.getNSplitter()]; ('>!dXA$  
nEndPos = new long[bean.getNSplitter()]; <8'}H`w%  
} y0z}[hZ  
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} **oN/5  
@Gl=1  
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public void run() V a<L[8  
{ k/*r2 C  
//获得文件长度 4Sw)IU~K(  
//分割文件 L-q.Q  
//实例FileSplitterFetch &t`l,]PQ=6  
//启动FileSplitterFetch线程 Id9hC<8$dq  
//等待子线程返回 `Up3p24  
try{ ':J[KWuV  
if(bFirst) -MeGJX:^I  
{ yV_aza  
nFileLength = getFileSize(); n)[{nkS6[  
if(nFileLength == -1) \]GBd~i<  
{ meE&, {  
System.err.println("File Length is not known!"); Kc0KCBd8];  
} Y
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else if(nFileLength == -2) l&[x)W  
{ 7mt;qn?n  
System.err.println("File is not access!"); s)\%%CM  
} =M>pL+#  
else }c$Zlb  
{ }5u$/c@f1  
for(int i=0;i<nStartPos.length;i++) %r?Y!=0  
{ +AO(e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]~GwZB'M  
} 3+0$=ef  
for(int i=0;i<nEndPos.length-1;i++) r 1nl!  
{ R8sj>.I9j  
nEndPos = nStartPos[i+1]; &KmVtj  
} COZ<^*=A#p  
nEndPos[nEndPos.length-1] = nFileLength; (~#{{Ja  
} I^emH+!MW  
} ,eW K~ pa  
&iORB  
+coVE^/w  
//启动子线程 jEo)#j];`<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; TY"8.vd  
for(int i=0;i<nStartPos.length;i++) i]Njn k  
{ C|*U)#3:F  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~+ Mp+gE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &gR)Y3  
nStartPos,nEndPos,i); &s-iie$"@x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Cjc>0)f&.  
fileSplitterFetch.start(); bbCH(fYbu  
} #rD0`[pz  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),
3"FvYv{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); hSr2<?yk  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Jz
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nEndPos = " + nFileLength); `tw[{Wb  
// fileSplitterFetch[nPos.length-1].start(); U[,."w]T  
XYj!nx{k,  
>pdWR1ox  
//等待子线程结束 W|'7)ph  
//int count = 0; Y7vUdCj  
//是否结束while循环 b~>kTO  
boolean breakWhile = false; `ECY:3"$KA  
&6wD  
A{NKHn>%`  
while(!bStop) /<C}v~r  
{ Y&wtF8  
write_nPos(); !>RDHu2n  
Utility.sleep(500); EdcbWf7  
breakWhile = true; KTtB!4by  
#!?jxfsFa  
3EkCM_]  
for(int i=0;i<nStartPos.length;i++) ``mnk>/  
{ (w[#h9j  
if(!fileSplitterFetch.bDownOver) &X3G;x2;  
{ w}|XSJ!  
breakWhile = false; A#7/,1h\  
break; _nwsIjsW  
} L!;"73,&(8  
} *Ri\7CqU"6  
if(breakWhile) {'#1do}{  
break; 'Dn\.x^]1  
_+7+90u  
11VtC)  
//count++; *qa.hqas  
//if(count>4) kI?+\k\V`  
// siteStop(); [x%[N)U3  
} 6;:z?Q  
t|PQ4g<  
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System.err.println("文件下载结束！"); o%yfR.M6$  
} 3#A4A0  
catch(Exception e){e.printStackTrace ();} g?.y7!m  
} _^/k  

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.
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//获得文件长度 ='vD4}"j  
public long getFileSize() _jb'HP  
{ y'5`Uo?\",  
int nFileLength = -1; ty8>(N(~  
try{ e

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URL url = new URL(siteInfoBean.getSSiteURL()); PZ>(cvX&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v!`:{)2C  
httpConnection.setRequestProperty("User-Agent","NetFox"); l|81_BC"  
q4#$ca[_ak  
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int responseCode=httpConnection.getResponseCode(); f\;w(_  
if(responseCode>=400) i/.#`  
{ v,'k2H  
processErrorCode(responseCode); g#k@R'7E  
return -2; //-2 represent access is error 8NkyT_\  
} u`CHM:<<?  
5e3p9K`5  
#iKPp0`K*  
String sHeader; Z9G4in8  
{'Y()p3kl  
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for(int i=1;;i++) Gb
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{ h`
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); /X]gm\x7s  
//Utility.log(in.readLine()); hg%iv%1B'  
sHeader=httpConnection.getHeaderFieldKey(i); -{}(U  
if(sHeader!=null) 9Af nMD  
{ fH@cC`  
if(sHeader.equals("Content-Length")) 4.Q[Tu  
{ ,.kmUd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +DG-MM%\  
break; 1M.#7;#B3  
} Sp6==(:.  
} [+d~He  
else x<`^4|<  
break; 2 OV$M~  
} :t9
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} o|u4C{j  
catch(IOException e){e.printStackTrace ();} .sc80i4  
catch(Exception e){e.printStackTrace ();} kh@O_Q`j  
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Utility.log(nFileLength); nrA 4N1  
|)v}\-\#  
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return nFileLength; 5t-d+vB  
} ,{\Ae"{6  
^I|i9MH  
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//保存下载信息（文件指针位置） M)ao}m>  
private void write_nPos() ;jaugKf  
{ "uP*pR^  
try{ HY eCq9S  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *P5\T4!+d  
output.writeInt(nStartPos.length); J5{  
for(int i=0;i<nStartPos.length;i++) .%dGSDru  
{ S,C c0)j>  
// output.writeLong(nPos); ;w+  
output.writeLong(fileSplitterFetch.nStartPos); FZ}^)u}o  
output.writeLong(fileSplitterFetch.nEndPos); 4DDBf j  
} <7>1Z 82)  
output.close();  zR'EQ  
} YM#MfL#  
catch(IOException e){e.printStackTrace ();} tBfmjxv  
catch(Exception e){e.printStackTrace ();} z.\r7  
} 7QnWw0  
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-9.lFuI  
//读取保存的下载信息（文件指针位置） (
]\p'%A)  
private void read_nPos() $
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{ TBrwir  
try{ j24DL+  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !'rdHSy
 
int nCount = input.readInt(); xo?'L&%  
nStartPos = new long[nCount]; !;mn]wR>a  
nEndPos = new long[nCount]; KAD2_@l  
for(int i=0;i<nStartPos.length;i++) - AgD  
{ ;-JFb$m  
nStartPos = input.readLong(); J=78p#XUg  
nEndPos = input.readLong(); ?H,f|nc  
} tY]?2u%)  
input.close(); ~]RfOpq^w  
} N?-ZvE\C  
catch(IOException e){e.printStackTrace ();} i ]8bj5j{  
catch(Exception e){e.printStackTrace ();} AZ4?N.X?  
} 1\UU"  
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private void processErrorCode(int nErrorCode) ZzgzeT+bv  
{ Cw(ypu  
System.err.println("Error Code : " + nErrorCode); qD\9h`a  
} a%U#PF6   
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:<B_V<  
//停止文件下载 1U.X[}e  
public void siteStop() =b
ja\r{  
{ J ;z
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bStop = true; k7rg:P  
for(int i=0;i<nStartPos.length;i++) lEwQj[ k  
fileSplitterFetch.splitterStop(); E9I08AODS  
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n{MTh_C4n  
}  XD8I.q  
} csLbzDg  
//负责部分文件的抓取 wG7>2
*(  
**FileSplitterFetch.java RD)Vb$.B:  
*/ e21J9e6z  
package NetFox; y;fF|t<y  
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import java.io.*; :ChXzZ  
import java.net.*; \WTKw x  
r9N?z2X  
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public class FileSplitterFetch extends Thread { kO*\JaD  
Or?c21un  
_+aR|AEC  
String sURL; //File URL bcy  
long nStartPos; //File Snippet Start Position 6pS}\aD  
long nEndPos; //File Snippet End Position Q<D_QJ  
int nThreadID; //Thread's ID v@GhwL  
boolean bDownOver = false; //Downing is over )h 6w@TF  
boolean bStop = false; //Stop identical L)\<7  
FileAccessI fileAccessI = null; //File Access interface !idVF!xG  
3b0|7@
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c-(dm:  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 65O 8?
I  
{ vdgK3I  
this.sURL = sURL; xFThs,w  
this.nStartPos = nStart; 8N"WKBj|_d  
this.nEndPos = nEnd; UcB&pt&  
nThreadID = id; `W+-0F@Y?@  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "62g!e}!c  
} GT]>  
_6h.<BR  
3V^5 4_  
public void run() }AB_i'C0  
{ BxV>s+o&]  
while(nStartPos < nEndPos && !bStop) )7+z/y+[n  
{ 6XZjZ*)W  
YRBJ(v"9  
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try{ #T>?g5I  
URL url = new URL(sURL); O:rfDO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); dr&G>  
httpConnection.setRequestProperty("User-Agent","NetFox"); P`Now7! GW  
String sProperty = "bytes="+nStartPos+"-"; cU ?F D  
httpConnection.setRequestProperty("RANGE",sProperty); <N~9=g3  
Utility.log(sProperty); y5aPs z  
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InputStream input = httpConnection.getInputStream(); #*y.C[^5{  
//logResponseHead(httpConnection); _e>N3fT  
=ca[*0^Z7  
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byte[] b = new byte[1024]; |X XO0  
int nRead;  *$DD+]2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) wM7Iu86  
{ LdO
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nStartPos += fileAccessI.write(b,0,nRead); b|Ge#o  
//if(nThreadID == 1) 8:S+*J[gSn  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q&9]4j  
} SKNHLE}  
d&|5Rk ~  
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Utility.log("Thread " + nThreadID + " is over!"); pYAKA1F  
bDownOver = true; '4#NVXVQm  
//nPos = fileAccessI.write (b,0,nRead); DxN\ H"  
} M,ybj5:6  
catch(Exception e){e.printStackTrace ();} _](y<O^9yO  
} c C) <Y#1  
} 8|\ -(:v  
|k]]dP|:'  
@@\px66  
//打印回应的头信息 kxEq_FX  
public void logResponseHead(HttpURLConnection con) 9SA%'  
{ `DSFaBj,  
for(int i=1;;i++) XI$W  
{ U
ea2WJpX  
String header=con.getHeaderFieldKey(i); H<ovIMd  
if(header!=null) z!b:|*m]w  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Y?K?*`Pkc1  
Utility.log(header+" : "+con.getHeaderField(header)); ALO/{:l(  
else NPO!J^^  
break; *w^!\  
} 0(u}z  
} o2$A2L9P  
wi.E$RckD  
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public void splitterStop() RZq_}-P,.c  
{ <Tbl|9  
bStop = true; ZR)M<*$  
} ~Hg*vCd ?  
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}
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/* lF46W  
**FileAccess.java g co;8e_  
*//文件访问(定位，写) In:V.'D/>t  
package NetFox; Cl&)#  
import java.io.*; o,J8n;"l  
OU]"uV<(  
%Rr_fSoV  
public class FileAccessI implements Serializable{ 9|@5eN:N  
&E!m(|6?+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ih75C"  
RandomAccessFile oSavedFile; ]JmE(Y1(1  
long nPos; N 5
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&"Cy&[  
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public FileAccessI() throws IOException E/1:4?1 S  
{ Y37qjV  
this("",0); ,|zwY~lt5  
} pxyFM@Z](  
l;aO"_E1m  
T(cpU,Q  
public FileAccessI(String sName,long nPos) throws IOException ?wIEXKI  
{ wJgGw5  
oSavedFile = new RandomAccessFile(sName,"rw"); #X{lV]Z  
this.nPos = nPos; *U8,Q]gS  
oSavedFile.seek(nPos); &!'R'{/?X  
} ,%V%g!6{  
w'xPKO$bzR  
23bTCp.d  
public synchronized int write(byte[] b,int nStart,int nLen) u-.nR}DM_  
{ lPA}06
hU  
int n = -1; "18cD5-#  
try{ JV!F<  
oSavedFile.write(b,nStart,nLen); w#L`|cYCm  
n = nLen; PCc{0Rp\vk  
} _a`/{M|  
catch(IOException e) %(\et%[]  
{ brqmi<*9"[  
e.printStackTrace (); Eh9{n,5-  
} E(*CEW.V*  
-"2
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return n; @lh]?|*[  
} {e[~1]j3  
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} BGu<1$G  
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}tH_Y
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/* y;.5AvfD  
**SiteInfoBean.java bK!uR&i^l  
*/ S\k(0Sv9D  
package NetFox; m'ZxmsFo  
=C^4nP-  
zmFKd5  
public class SiteInfoBean {
)fke;Y0  
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private String sSiteURL; //Site's URL {q);1Nnf  
private String sFilePath; //Saved File's Path ExOSHKU,e  
private String sFileName; //Saved File's Name Vg"vC  
private int nSplitter; //Count of Splited Downloading File +KP&D.wIo  
M=5hp&=  
%w3tzE1Hq  
public SiteInfoBean() +\cG{n*  
{//nSplitter的缺省值为5 {]7lh#M  
//default value of nSplitter is 5 G98fBw  
this("","","",5); 5^2P\y(?  
} I$fm"N  
kNrd=s,-]D  
-x>2Wb~%  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~(.&nysZ-  
{ v dU)
  
sSiteURL= sURL; {-)I2GJav  
sFilePath = sPath; *OY Nx4k  
sFileName = sName; [O3)s]|  
this.nSplitter = nSpiltter; ;![rwra  
[](] "r  
t"&qaG{  
} j3'SM#X  
<x:^w'V_b  
WG5)-;>q|  
public String getSSiteURL() d!4:nvKx  
{ 6[a;83  
return sSiteURL; 7<93n`byM  
} IG8I<+<o  
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@dhnpR:L  
public void setSSiteURL(String value) R& HkWe  
{ &f/"ir[8i  
sSiteURL = value; FMqes5\ 3  
} [T2!,D.  
#8B4*gAM  
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public String getSFilePath() Ap
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{ 1Zgv+
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return sFilePath; 3s,a%GOk  
} uVZX53 ,g  
Rs "#gT  
%VO>6iVn  
public void setSFilePath(String value) /}3I:aJwb  
{ +)*oPSQ5  
sFilePath = value; AXPdgo6  
} =O~Y6|  
7vB6IF  
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public String getSFileName() >d^DN;p  
{ 0@}:`OynX  
return sFileName; #UqE%g`J  
} 0$.;EGP  
_>Oc>.MB  
l }]"X@&G  
public void setSFileName(String value) E-HK=D&W/  
{ 9_J'P2e  
sFileName = value;  y7.oy"  
} 9&OhCrxW-  
Q6%Pp_$k  
&nwk]+,0W#  
public int getNSplitter() fv
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{ C9nCSbGMY{  
return nSplitter; m~8=?R+m  
} \m~Oaf;$  
ePiZHqIsv/  
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public void setNSplitter(int nCount) o(oD8Ni  
{ $NwPGy?%  
nSplitter = nCount; kFQx7m  
}  J?qikE&  
} m/ngPeZ  
HXQ }B$V  
q$jwH] .  
/* E#c9n%E\sz  
**Utility.java  lLNI5C  
*/ zKNac[:  
package NetFox; T&]IPOH9  
XiAflO  
LCok4N$o  
public class Utility { ]nm(V  
a*!9RQ  
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public Utility() 4'H)h'#C  
{ m%)S<L7 l  
]|B_3*A  
>,c'Z<TM  
} 82yfPQ&UI  
XPMvAZL  
//线程睡眠 fs8C ^Ik>~  
public static void sleep(int nSecond) Cuo"6, M  
{ !1`f84
d  
try{ C0H@  
Thread.sleep(nSecond); DN|+d{^lN  
} +Q+!#  
catch(Exception e) UW-`k1  
{ %WtF\p  
e.printStackTrace (); ro18%'RRI  
} kjO
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} X^d}eWP`I  
A}sdi4[`  
//日志 be>KG ZU0  
public static void log(String sMsg) bJFqyK:6  
{ z"V`8D  
System.err.println(sMsg); cEEnR1  
} XknbcA|  
"2`/mtMon  
Q57Z~EsF  
public static void log(int sMsg) >&)|fV&4  
{ gflO0$i  
System.err.println(sMsg); ky[^uQ>0  
} zu``F]B  
} u\=yY.   
*.+N?%sAP)  
_>G=xKA#e  
/* %wIb@km  
**TestMethod.java (^^}Ke{J  
*/ Gvc/o$_  
package NetFox; C59H| S  
^PowL:  
7:wf!\@I  
public class TestMethod { T$tO[QR/  
pYX!l:hk  
!GtCOr\'  
public TestMethod() 13/U4-%b2  
{ ///xx/weblogic60b2_win.exe r1.OLn?C  
try{ ;%O>=m'4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); BU=Ta$#BZ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 1|5TuljTd  
SiteFileFetch fileFetch = new SiteFileFetch(bean); KwhATYWQb  
fileFetch.start(); zO3}c3D~q  
} [k7 ;^A5/  
catch(Exception e){e.printStackTrace ();} 42wZy|oqp  
\7 }{\hY-  
w/Wd^+IIn  
} :bz;_DZP  
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4,:)%KB"V  
public static void main(String[] args) @;>Xy!G  
{ kj'  
new TestMethod(); =p#:v  
} .<-~k@ P  
} zA@w[.  
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