http断点续传简单实现（java)

/* >U\P^y
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**SiteFileFetch.java x3 ( _fS  
*/ 2V; Dn$q  
package NetFox; Z-}A"n
 
import java.io.*; ql5&&e=-  
import java.net.*; ,bM):  
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public class SiteFileFetch extends Thread { 'bH~KK5  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 7;.Iat9gMf  
long[] nStartPos; //开始位置 z&#^9rM"  
long[] nEndPos; //结束位置 XLYGhM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 lOb(XH
9  
long nFileLength; //文件长度 X<W${L$G  
boolean bFirst = true; //是否第一次取文件 4%<wxrod  
boolean bStop = false; //停止标志 G[`2Nd<  
File tmpFile; //文件下载的临时信息 PD^ 6Ywn>s  
DataOutputStream output; //输出到文件的输出流 eq"Xwq*  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 8ZjRMr}  
public SiteFileFetch(SiteInfoBean bean) throws IOException `{IL.9M!f  
{ icVB?M,m  
siteInfoBean = bean; >bmdu\j5R  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3,hu3"@k  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]M"U 'Z  
if(tmpFile.exists ()) ^HuB40  
{ KT(v'KE 1  
bFirst = false; w4Hq|N1-Y  
read_nPos(); :T@}
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} )Xt#coagS  
else c%wztP;L  
{ jc!V|w^  
nStartPos = new long[bean.getNSplitter()]; LV$Ko_9eA  
nEndPos = new long[bean.getNSplitter()]; 'vq0Tw5  
} Ed-3-vJej6  
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} hVFZQJ?cv  
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public void run() Tk 'Pv  
{ 9G7Brs:  
//获得文件长度 Bz%wV-  
//分割文件 Wi\k&V
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//实例FileSplitterFetch \fvm6$ rZ^  
//启动FileSplitterFetch线程 ^rY18?XC+:  
//等待子线程返回 ,j(E>g3  
try{ n8\88d  
if(bFirst) ?-0, x|ul  
{ qrZ3`@C4k  
nFileLength = getFileSize(); d|W=_7z  
if(nFileLength == -1) Y}C|4"V  
{ @S5HMJ2=  
System.err.println("File Length is not known!"); *].qm g%  
} m' |wlI[lq  
else if(nFileLength == -2) >-3>Rjo>  
{ tU!Yg"4Q  
System.err.println("File is not access!"); f
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} MlS5/9m@^  
else @1bl<27  
{ G%!i="/9  
for(int i=0;i<nStartPos.length;i++) _2<UcC~  
{ 4Xwb`?}-  
nStartPos = (long)(i*(nFileLength/nStartPos.length));  VS7  
} U ){4W0  
for(int i=0;i<nEndPos.length-1;i++) 3=Uyt  
{ ?h|DeD!s  
nEndPos = nStartPos[i+1]; [yc7F0Aw  
} H_| re  
nEndPos[nEndPos.length-1] = nFileLength; M*Q}^<E*  
} x",ktE>9  
} +T,A^(&t  
b53s@7/mq  
Vvfd?G"  
//启动子线程 zyP/'X_~:  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _sL;E<)y(  
for(int i=0;i<nStartPos.length;i++) U(OkTJxv+  
{ 7@k3-?q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), G-:7,9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7>0/$i#'Vl  
nStartPos,nEndPos,i); n`jG[{3t&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6T_Ya)  
fileSplitterFetch.start(); cc1M9kVi  
} |]Hr"saO0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +n%8
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); sK/ymEfRv  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", N K@6U_/W  
nEndPos = " + nFileLength); TnKOr~@*  
// fileSplitterFetch[nPos.length-1].start(); c&h8Qk3  
Yu
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(4C)] RHQ  
//等待子线程结束 >@-.rkd(  
//int count = 0; Y;E'gP-J  
//是否结束while循环 t56PzT'M  
boolean breakWhile = false; {%&04yq+  

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2#/sIu-L  
while(!bStop) X(8LhsP  
{ ^q%f~m,O<  
write_nPos(); nYvkeT  
Utility.sleep(500); Lm1JiPs d  
breakWhile = true; eIf-7S]m  
,[dvs&-*  
[a~@6*=  
for(int i=0;i<nStartPos.length;i++) 3Q7PY46  
{ q@wX=  
if(!fileSplitterFetch.bDownOver) kK:Wr&X0H  
{ &t!f dti  
breakWhile = false; tuY=)?  
break; 9JILK9mVO  
} 8|L5nQ  
} & \"cV0  
if(breakWhile) WYcZD_  
break; (hKjr1s  
jzWgyI1b  
#~qzaETv,  
//count++; fwUF5Y  
//if(count>4) Zz'g&ewo  
// siteStop(); `/i/AZ{  
} ^AXH}g  
_c:th{*  
,KPrUM}  
System.err.println("文件下载结束！");  Yg2P(  
} #8BI`.t)j  
catch(Exception e){e.printStackTrace ();} X_Pbbx_j  
} z-sq9Qp&x  
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//获得文件长度 e~R_bBQ0  
public long getFileSize() a6It1%a+  
{ YZ<5-C  
int nFileLength = -1; k!WeE#"(  
try{ 2$o\`^dy  
URL url = new URL(siteInfoBean.getSSiteURL()); #P!M"_z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xsS;<uCD  
httpConnection.setRequestProperty("User-Agent","NetFox"); Of9 gS-m  
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{Dy,u%W?  
int responseCode=httpConnection.getResponseCode(); BmYX8j]  
if(responseCode>=400) }
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{ *#?9@0b@  
processErrorCode(responseCode); EW`WFBjj  
return -2; //-2 represent access is error -0NkAQrg  
} [I<J6=  
wCj)@3F  
hwi_=-SL  
String sHeader; pm[i#V<v  
66_=bd(9  
|X6R2
I  
for(int i=1;;i++) Rz*GRe
 
{ 6 lEv<)cC  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vuJEPn%
 
//Utility.log(in.readLine()); AOV{@b(  
sHeader=httpConnection.getHeaderFieldKey(i); _?I*:: I  
if(sHeader!=null) 34_ V&8  
{ <R_)[{ 7  
if(sHeader.equals("Content-Length")) "%_T7A ![  
{ U5?QneK  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); t23W=U  
break; ^L.'At  
} cveQ6 -`K  
} *Aug7 HlS  
else p^ OHLT  
break; N'pYz0_H  
} +4[9Eb'k=  
} ]-;JHB5A_:  
catch(IOException e){e.printStackTrace ();} - _%~b  
catch(Exception e){e.printStackTrace ();} 'jy
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Utility.log(nFileLength); l$R9c+L=  
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return nFileLength; 'Ddzlip  
} hyhm{RC?[  
6 Pdao{P  
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//保存下载信息（文件指针位置） rD !GEU
 
private void write_nPos() 2{oQ  
{ Np$ue }yr  
try{ l2Rnyb<;;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); it-2]N
w  
output.writeInt(nStartPos.length); E!L_"GW  
for(int i=0;i<nStartPos.length;i++) J5xZLv  
{ T~g`;Q%i  
// output.writeLong(nPos); -"#jRP]#  
output.writeLong(fileSplitterFetch.nStartPos); _U^G*EqL*  
output.writeLong(fileSplitterFetch.nEndPos); vCOtED*<  
} 2gEF$?+q?  
output.close(); K&T.~2'>  
} ,,ML^ey  
catch(IOException e){e.printStackTrace ();} _C|j"f/}  
catch(Exception e){e.printStackTrace ();} L2%D$!9  
} ]bstkf}~u  
/`y^z"!  
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//读取保存的下载信息（文件指针位置） LIyb+rH#yg  
private void read_nPos() wk1/&  
{ W
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try{ zp``e;gY  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); vM:c70=  
int nCount = input.readInt(); t=jG$
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nStartPos = new long[nCount]; ^U,Dx  
nEndPos = new long[nCount]; gplrJaH@  
for(int i=0;i<nStartPos.length;i++) i#*lK7  
{ 7[0CVWs,  
nStartPos = input.readLong(); 4jjo%N  
nEndPos = input.readLong(); }I18|=TB  
} J(P'!#z^  
input.close(); :" JEC'  
} \H1t<B,  
catch(IOException e){e.printStackTrace ();} Tiimb[|  
catch(Exception e){e.printStackTrace ();} #GUD^#Jh  
} ##Qy6Dc  
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private void processErrorCode(int nErrorCode) \+x#aN\  
{ 6X!jNh$oF  
System.err.println("Error Code : " + nErrorCode); ]c6h'}  
} 10N0?K"  
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//停止文件下载 - "{hP  
public void siteStop() OgHqF,0MN  
{ ]M~7L[  
bStop = true; u0qTP]  
for(int i=0;i<nStartPos.length;i++)
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fileSplitterFetch.splitterStop(); X `F>kp1  

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} O2U}jHsd  
} [EK^0g
 
//负责部分文件的抓取 X|}Q4T`  
**FileSplitterFetch.java =p:~sn#  
*/ 5Y@Hb!5D  
package NetFox; O]@s`w  
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import java.io.*; 'Axe:8LA'  
import java.net.*; t5P8?q\  
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public class FileSplitterFetch extends Thread { KJs`[,;<  
tC.etoh  
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String sURL; //File URL }U%T6~_wR  
long nStartPos; //File Snippet Start Position c}H}fyu%n  
long nEndPos; //File Snippet End Position QC6QqcOX  
int nThreadID; //Thread's ID  D@]/%;  
boolean bDownOver = false; //Downing is over u('`.dwkc  
boolean bStop = false; //Stop identical {z
9z#8`C;  
FileAccessI fileAccessI = null; //File Access interface RPjw12Ly  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *Y!RU{w+Z  
{ b~<:k\EE  
this.sURL = sURL; @3~Wukc  
this.nStartPos = nStart; 6^2='y~e  
this.nEndPos = nEnd; %:sP#BQM  
nThreadID = id; X0]$Ovq(l  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]
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} ,?+uQXfX
R  
#5iwDAw:|r  
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public void run() xl,6O!aR  
{ jzwHb'4B3  
while(nStartPos < nEndPos && !bStop) aN!,\D  
{ ,kl``w|1M  
*)vy%\  
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try{ ;hh.w??  
URL url = new URL(sURL); -M4VC^_  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $if(n||  
httpConnection.setRequestProperty("User-Agent","NetFox"); rX)_!mR  
String sProperty = "bytes="+nStartPos+"-"; ]u:Ij|.'y0  
httpConnection.setRequestProperty("RANGE",sProperty); _94R8?\_V7  
Utility.log(sProperty); w$""])o,  

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InputStream input = httpConnection.getInputStream(); "{c@}~  
//logResponseHead(httpConnection); CioS}K  
-"XHN=H  
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byte[] b = new byte[1024]; %zhSSB=BJ  
int nRead; 3T[zieX  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) czB),vooz  
{ zz8NBO  
nStartPos += fileAccessI.write(b,0,nRead); z(#dL>d$'  
//if(nThreadID == 1) n;~'W*Ln0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Qo*OC 9E`  
} s{42_O?,c  
>gl.ILo  
o>&-B.zq  
Utility.log("Thread " + nThreadID + " is over!"); y I[kaH"J  
bDownOver = true; 9! yDZ<s  
//nPos = fileAccessI.write (b,0,nRead); BL-7r=Z  
} 6_:KFqc W  
catch(Exception e){e.printStackTrace ();} w{4#Q[  
} iRM ?_
|  
} Digx#'#jf  
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v+( P4fS  
//打印回应的头信息 p4$4;)  
public void logResponseHead(HttpURLConnection con) `7.$ A U  
{ ij.NSyk9  
for(int i=1;;i++) Z2-"NB  
{ Fc|N6I'o  
String header=con.getHeaderFieldKey(i); #eF k  
if(header!=null) #T8PgmR  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `3z6y&dmx  
Utility.log(header+" : "+con.getHeaderField(header)); ]?NiY:v  
else tg9{(_t/W  
break; G'wyH[ d/  
} $J0o%9K   
} !LsIHDs
4  
;{0%Vp{  
_T;Kn'Gz(&  
public void splitterStop() 6LqF*$+$`  
{ Hr \vu`p$  
bStop = true; :!FGvR6  
} @ *5+ZAF  
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} R{6M(!x  
} V"A;5j`  
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/* /4upw`35]  
**FileAccess.java c@KNyBy2  
*//文件访问(定位，写) >GmO8dK  
package NetFox; &4*f28 s  
import java.io.*; <y#@v  G  
N37CAbw0  
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public class FileAccessI implements Serializable{ Fu[GQ6{f  
*zdUCX  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 n-1  
RandomAccessFile oSavedFile; P!{J28dj  
long nPos; |\)Y,~;P  
a|k*A&5u2  
}{[JS=A^  
public FileAccessI() throws IOException Yqv!ZJ6  
{ FS*J8)  
this("",0);
" ^!=e72  
} F3x*dq2  
cb/$P!j7  
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public FileAccessI(String sName,long nPos) throws IOException uX6rCokr  
{ & sXMB  
oSavedFile = new RandomAccessFile(sName,"rw"); :z\||f  
this.nPos = nPos; kZfj"+p_S  
oSavedFile.seek(nPos); wBEBj7(y  
} FMitIM*]   
.Vs|&c2im  
7324#HwS  
public synchronized int write(byte[] b,int nStart,int nLen) 5JG`FRW!  
{ -<tTT  
int n = -1; 3w/z$bj  
try{ b$tf9$f  
oSavedFile.write(b,nStart,nLen); GKG:iR)  
n = nLen; +Q"XwxL<6  
} qVvnl  
catch(IOException e) -WGlOpg0;  
{ h|<;:o?yh  
e.printStackTrace (); "kKIv|`  
} tv;?W=&P  
2/x~w~3U  
Z`n "}{  
return n; ^}<]sjmk  
} C\0,D9  
>}d6)s|   
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} @[Wf!8_  
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GbvbGEG  
/* hK3Twzte  
**SiteInfoBean.java 8L`wib2  
*/ YI]/gWeu  
package NetFox; %2beoH'  
|{rhks~  
9MbF:  
public class SiteInfoBean { fS%B/h=  
"Q{7X[$$^  
^C}f|{J  
private String sSiteURL; //Site's URL U?Vik  
private String sFilePath; //Saved File's Path ]UZP dw1D  
private String sFileName; //Saved File's Name ghk"XJ|  
private int nSplitter; //Count of Splited Downloading File cu#r#0U-  
6HH:K0j3'  
u5`b")a  
public SiteInfoBean() T ^/\Rr  
{//nSplitter的缺省值为5 "J`#  
//default value of nSplitter is 5 BiZYGq  
this("","","",5); tw] l  
} dd4^4X`j  
Z'd]
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .4y44: T  
{ JYLAu4s6  
sSiteURL= sURL; vpdT2/F  
sFilePath = sPath; I~-sBMm(w  
sFileName = sName; 6~6 vwp  
this.nSplitter = nSpiltter; X#X/P  
J~N!. i  
MI`<U:-lP  
} 1b@]^Ue  
xg;F};}5$  
6f+@@=Xc  
public String getSSiteURL() rgEN~e'  
{ -JclEp  
return sSiteURL; )?(_vrc<  
} SN$3cg]z  
Q0L1!}w   
R,-DP/ (im  
public void setSSiteURL(String value) <4I`|D3@  
{ E:P_CDSd]  
sSiteURL = value; "a<:fEsSE  
} C~M,N|m+^  
6hHMxS^o  
^vI`#}?  
public String getSFilePath() w=~X6[+3  
{ /5Yl, P  
return sFilePath; 5K=>x<  
} #zc$cr  
]hbrzvo  
&b]_#c  
public void setSFilePath(String value) j(c;r>  
{ p`'3
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sFilePath = value; )0=H)k0  
} ]zI*}(adu  
;NGSJfn  
66po SZR@  
public String getSFileName() m
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{ l_ LH!Tu  
return sFileName; ZtpbKy!\$B  
} "}0)~,{xB  
Ls&-8  
-R`nitf  
public void setSFileName(String value) Y{8}z ZD  
{ $$'[%  
sFileName = value; FyV $`c$  
} GvL\%0Ibx  
] B>.}  
~hT(uxU/  
public int getNSplitter() 4v`;D,dI
u  
{ 6L-3cxqf\  
return nSplitter; U \F ?{/  
}
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}50s\H._C  
\{o<-S;h  
public void setNSplitter(int nCount) 1Q$/L+uJ5  
{ ^fbzlu?G4-  
nSplitter = nCount; 6Zv-kG  
} e`?o`@vO,  
} {G=|fgz  
?%
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+rKV*XX@  
/* zOis}$GR  
**Utility.java )OFf nKh  
*/ fD2 N}  
package NetFox; Na+3aM%%  
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5zF$Q{3  
public class Utility { ,F=FM>o  
X6r3$2!  
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public Utility() 2rM/kF >g  
{ H
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y`pgJO  
{7EpljH@  
} w%%*3[--X  
,/dW*B  
//线程睡眠 es\Fn#?O  
public static void sleep(int nSecond) @$;I%  
{ 0fN; L;v  
try{ 26=G%F6  
Thread.sleep(nSecond); VD+v\X_  
} |[$TT$
Fb  
catch(Exception e) OS=~<ba  
{ +]e) :J  
e.printStackTrace (); -CTLQyj)  
} a*nCvZ  
}  wKbU}29c  
8,)<,g-/=  
//日志 b\UE+\a&  
public static void log(String sMsg) )vGxF}I3  
{ O*>`md?MH  
System.err.println(sMsg); perhR!#J  
} 9e;:(jl^  
pR!m  
 $kxu-  
public static void log(int sMsg) j$P`/-N  
{ $@~sO0q  
System.err.println(sMsg); L$@qEsO  
} c7]0>nU;  
} m-Qy6"eW  
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=TA8]7S~U  
/* }|],UXk{xB  
**TestMethod.java CxrsP.  
*/  H@sM$8  
package NetFox; MwaRwk;  
FW3uq^  
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public class TestMethod { mJsU7bD`  
12l1u[TlS  

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public TestMethod() 
R?#.z#  
{ ///xx/weblogic60b2_win.exe UTO$L|K  
try{ r<DPh5ReY  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `6v24?z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -v9x tNg  
SiteFileFetch fileFetch = new SiteFileFetch(bean); H?;@r1ZAn  
fileFetch.start(); E*L5D4Kw  
} Wp^A.  
catch(Exception e){e.printStackTrace ();} af&P;#U  
O]t)`+%q  
 }D!o=Mg^  
} VL$?vI'  
U[hokwZ  
k|cP]p4,  
public static void main(String[] args) -2Dgr\M  
{ N({-&A.N  
new TestMethod(); _RWH$
L9  
} 6Z;D`X,5  
} "||' -(0  
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