http断点续传简单实现（java)

/* UFL0K  
**SiteFileFetch.java \wFhTJY  
*/ ze ?CoDx2  
package NetFox; $M-NR||k  
import java.io.*; *n,UOHlO  
import java.net.*; $CM4&{B"i  
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public class SiteFileFetch extends Thread { Ae.]F)w_\  
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SiteInfoBean siteInfoBean = null; //文件信息Bean }\U0[x#q  
long[] nStartPos; //开始位置 4sI3(z)9H  
long[] nEndPos; //结束位置 )S#j.8P'B  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 c_t7RWV}  
long nFileLength; //文件长度 5vYsA1Z
 
boolean bFirst = true; //是否第一次取文件 aK!xRnY  
boolean bStop = false; //停止标志 +B](5z4  
File tmpFile; //文件下载的临时信息 "\}21B~{7'  
DataOutputStream output; //输出到文件的输出流 ]gEu.Nth`  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） T4l-sJ'|  
public SiteFileFetch(SiteInfoBean bean) throws IOException k-io$  
{ $,g 3*A  
siteInfoBean = bean; |HNQ|r_5S  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); B{^`8Htrn  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); < rv1IJ  
if(tmpFile.exists ()) GCZu<,  
{ P"2Q&M_/  
bFirst = false; AUu5g  
read_nPos(); 4{g:^?1=  
} N"&$b_u[  
else 8xc8L1;  
{ Wn2Ny jX  
nStartPos = new long[bean.getNSplitter()]; ]j72P  
nEndPos = new long[bean.getNSplitter()]; ,.J<.#D3J  
} R%qX_m\0  
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A>H*`{}  
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} S.qk%NTTD  
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public void run() UUZ6N ZQI  
{ e=0l<Rj  
//获得文件长度 :v|r=#OI  
//分割文件 C#ZmgR  
//实例FileSplitterFetch $:xF)E  
//启动FileSplitterFetch线程 u XaL  
//等待子线程返回 3-4Nad  
try{ &@-1"-H  
if(bFirst) ,<`|-oa  
{ pg5@lC]J  
nFileLength = getFileSize(); *Pa2bY3:  
if(nFileLength == -1) &n}8Uw0440  
{ vcaBL<io  
System.err.println("File Length is not known!"); {yGZc3e1j  
} Kc%tnVyGh:  
else if(nFileLength == -2) {vf+sf^^q  
{ )6PJ*;p-  
System.err.println("File is not access!"); ,?P8m"  
} Lw!?T(SK  
else K<Yn_G  
{ mrhsKmH  
for(int i=0;i<nStartPos.length;i++) 2<p5_4"-U*  
{ Wm];pqN  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); d#X&Fi  
} <\qY" .`  
for(int i=0;i<nEndPos.length-1;i++) 3s88#_eT  
{ 5q0BG!A%T  
nEndPos = nStartPos[i+1]; xc:`}4  
} olUqBQ&ol  
nEndPos[nEndPos.length-1] = nFileLength; #fJ/KY
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} uzat."`d'  
} _|Y.!ZRYP  
!7kAJG g  
<=B1"'\  
//启动子线程 IMl9\U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b(+w.R(+Ti  
for(int i=0;i<nStartPos.length;i++) ,%"
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{ 2@"0}po#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), BH.:_Qrbh[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), I,?Fqg'sq  
nStartPos,nEndPos,i); 9n06n$F  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P wt ?9I  
fileSplitterFetch.start(); <k!mdj)  
} 8=ukS_?Vy  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), k)<~nc-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); b/a?\0^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", WHhR)$zC  
nEndPos = " + nFileLength); gxBl1  
// fileSplitterFetch[nPos.length-1].start(); o|b[(t$;O  
"@UU[o  
(ffOu#RQ3  
//等待子线程结束 9RCB$Ka6X  
//int count = 0; ~Q.8 U3"  
//是否结束while循环 /j=DC9_  
boolean breakWhile = false; ,}xpYq_/  
f4 Sw,A  
1FXzAc(c!  
while(!bStop) XcJ'm{=
 
{ ,6cbD  
write_nPos(); -KJ}.q>upq  
Utility.sleep(500); ` $QzTv   
breakWhile = true; ~/]\iOL  
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9.MGH2^L?  
for(int i=0;i<nStartPos.length;i++) Y_|K,T6Zj@  
{ b3CspBgC  
if(!fileSplitterFetch.bDownOver) A~yw8v5UF  
{ ?%8})^Dd>4  
breakWhile = false; Q(!}t"u  
break; Kq@m?h  
} [Ls2k&)0  
} )Rm 'YmO  
if(breakWhile) `E4!u=%  
break; g:uaI  
ctwhfS|Y0  
+ !E{L  
//count++; ((hJmaq  
//if(count>4) f:JYG]E&  
// siteStop(); Fw_bY/WN{  
} )ZQ9a4%  
4cVs(`g^  
R~x;X
3  
System.err.println("文件下载结束！"); s[{:>~{iq  
} -x3tx7%  
catch(Exception e){e.printStackTrace ();} "p6:ekw  
} #qiGOpTF.  
[][:/~q!  
(c*7VO;  
//获得文件长度 TS~Y\Cp  
public long getFileSize() cfy/*|  
{ Xdp`Z'g  
int nFileLength = -1; ]Gi+Z1q  
try{ E&T'U2  
URL url = new URL(siteInfoBean.getSSiteURL()); h
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j 44bF/  
httpConnection.setRequestProperty("User-Agent","NetFox"); nIN%<3U2  
YiQeI|{oN  
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int responseCode=httpConnection.getResponseCode(); #%=vy\r  
if(responseCode>=400) e{rHO,#A>  
{ 3ZJagJ\O  
processErrorCode(responseCode); y9re17{ X  
return -2; //-2 represent access is error k_|v)\4B  
} wr;|\<c  
8n."
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String sHeader; 5LhJ
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for(int i=1;;i++) Zc' >}X[G  
{ O>"r. sR  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ,N@Icl  
//Utility.log(in.readLine()); v[3hnLN%  
sHeader=httpConnection.getHeaderFieldKey(i); e$xv[9  
if(sHeader!=null) 0z'={6,  
{ wEHrer  
if(sHeader.equals("Content-Length")) 9'/|?I  
{ #QyK?i*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); G~iYF(:&  
break; q3pN/f;kr,  
} ja,L)b:  
} p#8LQP~0$  
else P20]>Hg  
break; 0F0(]7g^  
} AN:RY/ %Wo  
} <DlanczziF  
catch(IOException e){e.printStackTrace ();} (k)gZD9~{?  
catch(Exception e){e.printStackTrace ();} Pu\DYP:(  
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i&s=!`  
Utility.log(nFileLength); $M3A+6["H  
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return nFileLength; ph&H*Mc  
} by:xD25  
(a)@<RF`Q}  
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//保存下载信息（文件指针位置） C[<\ufclD  
private void write_nPos() w2C!>fJ]1  
{ Mpl,}Q!c  
try{ ]JCB^)tM  
output = new DataOutputStream(new FileOutputStream(tmpFile)); c7TWAG_+  
output.writeInt(nStartPos.length);
5P t}  
for(int i=0;i<nStartPos.length;i++) [,szx1  
{ :7PSZc:xE  
// output.writeLong(nPos); XL&
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output.writeLong(fileSplitterFetch.nStartPos); ka9v2tE\  
output.writeLong(fileSplitterFetch.nEndPos); U=cWvr65  
} )}9}"jrDlx  
output.close(); '/qe#S  
} U%PMV?L{  
catch(IOException e){e.printStackTrace ();} *,XJN_DKj  
catch(Exception e){e.printStackTrace ();} s:Ql](/B#  
} r1[T:B'  
MzW$Sl&:  
n
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//读取保存的下载信息（文件指针位置） bHH}x"d[x  
private void read_nPos() !.GY~f<d$  
{ Q,qylL  
try{ O/r<VTOp  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); A)p!w aG  
int nCount = input.readInt(); "ZPbK$+=yU  
nStartPos = new long[nCount]; t T/*ZzMq#  
nEndPos = new long[nCount]; ^~1@HcJo  
for(int i=0;i<nStartPos.length;i++) c$SxDYG  
{ Fe2
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nStartPos = input.readLong(); ve]95w9J  
nEndPos = input.readLong(); pS)X\Xyw  
} {ZYCnS&?CL  
input.close(); B>nd9Z '  
} H&Lbdu~E  
catch(IOException e){e.printStackTrace ();} 7X3l&J2C4l  
catch(Exception e){e.printStackTrace ();} McI4oD~"  
} 8lb `   
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private void processErrorCode(int nErrorCode) X1~A "sW[  
{ c+M@{EbuN  
System.err.println("Error Code : " + nErrorCode); !-o||rt  
} (C[S?@S  
qpH-P8V   
v+2qR0,LM  
//停止文件下载 'eXw`kw(  
public void siteStop() SmEd'YD!J  
{ \z
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bStop = true; ~SUl,Cs  
for(int i=0;i<nStartPos.length;i++) 2F(\}%UT~  
fileSplitterFetch.splitterStop(); "_}D{ws1  
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} n>+W]I&E  
} PvCE}bY{}  
//负责部分文件的抓取 c{P
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**FileSplitterFetch.java ;rdLYmmx^  
*/ m1Z8SM+  
package NetFox; *Bz&  
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import java.io.*; LBi>D`]  
import java.net.*; 7ZnQ] ?  
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public class FileSplitterFetch extends Thread { by[(9+/z$  
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u^[v{hv'H  
String sURL; //File URL >k-poBw  
long nStartPos; //File Snippet Start Position ) O^08]Y g  
long nEndPos; //File Snippet End Position n
-.k&B{a  
int nThreadID; //Thread's ID C#
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boolean bDownOver = false; //Downing is over $ wB  
boolean bStop = false; //Stop identical =h!m/f^x  
FileAccessI fileAccessI = null; //File Access interface Sw)ftC~d  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y{@[)M{<  
{ tB7aHZ|  
this.sURL = sURL; R6Lr]H  
this.nStartPos = nStart; y}`%I&]n  
this.nEndPos = nEnd; 0w]?yqn
E  
nThreadID = id; ,#haai(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 =)bc/309  
} :b-(@a7>  
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public void run()
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{ `,"Jc<R7Z  
while(nStartPos < nEndPos && !bStop) 56dl;Z)  
{ Z;:-8 HPDY  
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try{ 2S/7f:  
URL url = new URL(sURL); ZC-
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F6/
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httpConnection.setRequestProperty("User-Agent","NetFox"); z{x -Vfd  
String sProperty = "bytes="+nStartPos+"-"; EK^2 2vi$  
httpConnection.setRequestProperty("RANGE",sProperty); us+adS.l&  
Utility.log(sProperty); ,-Gw#!0  
L|?tcic  
x.RZ!V-  
InputStream input = httpConnection.getInputStream(); yAe}O#dy  
//logResponseHead(httpConnection); 'l;|t"R12  
@pz2}Hd|  
*UC^&5:  
byte[] b = new byte[1024]; @ XMC$s  
int nRead; oJy/PR3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) z_)$g=9$  
{ +L6$Xm5DAv  
nStartPos += fileAccessI.write(b,0,nRead); "'L SLp  
//if(nThreadID == 1) zx*f*L,6F  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?1sY S  
} [R$4n-$  
;Wdo*ysW  
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Utility.log("Thread " + nThreadID + " is over!"); XRkqMq%  
bDownOver = true; Jt"Wtr  
//nPos = fileAccessI.write (b,0,nRead); V96BtVsB  
} W0k_"uI  
catch(Exception e){e.printStackTrace ();} 9q?gmAn.  
} }$ der  
} 7=9jXNk Y  
]g :ZokU  
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//打印回应的头信息 1+'3{m \5T  
public void logResponseHead(HttpURLConnection con) +zvK/Fj2q  
{ z,WrLZC  
for(int i=1;;i++) paY%pU  
{ @z.!Dby  
String header=con.getHeaderFieldKey(i); t{9Ph]e  
if(header!=null)
r%4:,{HF  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "P~>AXcq  
Utility.log(header+" : "+con.getHeaderField(header)); CAO$Zt  
else % |V:F.f  
break; :gXj($  
}
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} bmLNR  
<Bwu N,}  
81&!!qhfS  
public void splitterStop() :([,vO:  
{ _19k@a  
bStop = true; A}8U;<\Ig  
} IftPN6(Z  
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} EifY
K  
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^H'#*b0u  
/* K^+B"  
**FileAccess.java Q5ux**(Wr  
*//文件访问(定位，写) (@ Bw@9  
package NetFox; 9Bn dbSi  
import java.io.*; 7">.{ @S  
x=k$^V~  
v-o/zud]]  
public class FileAccessI implements Serializable{ m(Oup=\%b}  
o?>)CAo  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 N{'k ]&  
RandomAccessFile oSavedFile; zI(Pti  
long nPos; Z'E@sc 9  
9
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public FileAccessI() throws IOException `&o|=  
{ GC~::m~  
this("",0); h W-[omr0  
} P VPwYmte  
;Zw28!#Rt  
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public FileAccessI(String sName,long nPos) throws IOException |R4](  
{ x/ez=yd*l  
oSavedFile = new RandomAccessFile(sName,"rw"); /Wa+mp  
this.nPos = nPos; V
:lDR20*\  
oSavedFile.seek(nPos); >v(Xc/oI
 
} ^0 t`EZ$  
m$kmoY/  
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public synchronized int write(byte[] b,int nStart,int nLen) q+ .=f.+Z  
{ <rkF2-K,  
int n = -1; >U17BGJ.  
try{ (HEjmQjE  
oSavedFile.write(b,nStart,nLen); >[#4Pb7_Y  
n = nLen; ?FLjvmE9  
} =y<Fz*aA  
catch(IOException e) (mzyA%;W  
{ ~DSle 3  
e.printStackTrace (); ,{%[/#~6  
} `hbM2cM  
N7[~Y2i  
&CS=*)>$  
return n; \"Np'$4eu  
} P?I"y,_p  
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- na]P3 s  
} f~53:;L/  
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E yNCky  
/* /<n_X:[)  
**SiteInfoBean.java Fax73vl|^a  
*/ u`ZnxD>  
package NetFox; =Vi+wH{xM  
, vR4x:W  
}\9qN!ol  
public class SiteInfoBean { Q5Wb)  
]UNmhF!W>u  
2Bx\nLf/ K  
private String sSiteURL; //Site's URL Q<M>+U;t  
private String sFilePath; //Saved File's Path u}pLO9V"`  
private String sFileName; //Saved File's Name D=
3NI  
private int nSplitter; //Count of Splited Downloading File R_-.:n%.z  
%rf<YZ.\  
C 9DRVkjj  
public SiteInfoBean() O)hNHIF  
{//nSplitter的缺省值为5 iM\W"OUl[  
//default value of nSplitter is 5 RW3&]l=  
this("","","",5); s}5;)>3~@  
} B${Q Y)t  
RSp=If+4  
 M;V2O;  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) m49)cK?  
{ 7{p,<Uz<"U  
sSiteURL= sURL; ec{pWzAe  
sFilePath = sPath; 5y.kOe4vH  
sFileName = sName; |kjk{  
this.nSplitter = nSpiltter; Tfj%Sb,zM  

d hh`o\$  
qLcs)&}/A  
} F&ux9zP  
-ohqw+D  
<FP&1Eg!|  
public String getSSiteURL() I
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{ -?j'<g0  
return sSiteURL; tF
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} >1W)J3  
,}J(&  
q>,i `*  
public void setSSiteURL(String value) 1B2>8N  
{ #HqXC\~n  
sSiteURL = value; 9Y0w SOSW  
} DRal{?CH  
gVb;sk^  
P#iBwmwN+.  
public String getSFilePath() yAaMYF@  
{ U1I2+;"#A  
return sFilePath; mzDbw-#  
} @<h@d_8^k  
H>2)R7h  
 \\6/"  
public void setSFilePath(String value) PKm
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{ mkgDg y  
sFilePath = value; 6?r}bs6Msx  
} '};pu;GA7  
2WqjNqx)6  
^`ny]3JA
 
public String getSFileName() ?8pRRzV$  
{ c1c8):o+V  
return sFileName; )A,MTi  
} 7V?TLGgd$  
\#L}KW  
(r.[b  
public void setSFileName(String value) bIR7g(PJ.b  
{ ZPRkk?M}.  
sFileName = value; [$$i1%c%Z<  
} %A%^;3@  
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~~z}yCl  
public int getNSplitter() `i;f  
{ <8~bb-U$  
return nSplitter; M/T ll]\|  
} BVU>M*k  
q9|'!m5K  
`5:b=^'D/  
public void setNSplitter(int nCount) RAPR-I;{  
{ x= X"4Mj0)  
nSplitter = nCount; (/JiOg^cw  
} uS;N&6;:  
} M$ CnaH  
F@UbUm2o  
jhg0H2C8  
/* #L ffmS  
**Utility.java bu$YW'  
*/ o-c.D=~  
package NetFox; "=@X>jUc  
O!#r2Y"?K1  
'| WY 2>/(  
public class Utility { ,#m:U5#h  
{W,&jC  
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public Utility() ].w~FUa  
{ },+ &y^  
o!bV;]  
j"1#n? 0  
} DxoW,GW  
GKIO@!@[  
//线程睡眠 OlI|.~  
public static void sleep(int nSecond) 4SlEc|'7@  
{ j`7q
7}  
try{ Bq@_/*'*Y  
Thread.sleep(nSecond); bi~1d"j  
} }hRw{#*8  
catch(Exception e) ozB2L\D7  
{ 9vZ:oO  
e.printStackTrace (); =#0f4z  
} F=EG#<@u  
} juIi-*R!  
OXp(rJ*bK  
//日志 #q?'<''d,
 
public static void log(String sMsg) wwaw|$  
{ h9RL(Kq{  
System.err.println(sMsg); :J6 xYy$  
} $raq,SP  
%^Zu^uu  
$\Oc]%  
public static void log(int sMsg) #83`T&Xw*  
{ 7x#QkImQ  
System.err.println(sMsg); []OmztB  
} ^pwT8Bp  
} 2fN2!OT  
P8[rp  
Sq:,6bcG  
/* *be"$Q  
**TestMethod.java Opavno%&  
*/ ?`hA:X<  
package NetFox; M47t(9krV  
uHeKttR-  
]sLdz^E3D  
public class TestMethod { w#}[=jy  
aGBUFCCa  
x4bmV@b  
public TestMethod() ]
}4JT  
{ ///xx/weblogic60b2_win.exe HQ:Y:  
try{ 4g+Dp&U  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =aBc.PJ^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \?tE,\Ln  
SiteFileFetch fileFetch = new SiteFileFetch(bean); uo9FLm  
fileFetch.start(); {;5\#VFg  
} Ahkq  
catch(Exception e){e.printStackTrace ();} Ua%;hI)j$  
-kzp>=  
}i._&x`):  
} _$+BYK@  
 gx9=L&=d  
g286 P_a`*  
public static void main(String[] args) U'@#n2p:k  
{ +N}yqgE  
new TestMethod(); ;"B@QPX  
} []:&WA9N  
} (h"-#q8$  
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