http断点续传简单实现（java)

/* F<4rn  
**SiteFileFetch.java G1:}{a5i_  
*/ %lKw+D  
package NetFox; hW7u#PY  
import java.io.*; 9O[IR)
O~  
import java.net.*; [X(m[u'%  
jzvK;*N  
{sTf4S\S  
public class SiteFileFetch extends Thread { n}p G&&;q  
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*MJm:  
SiteInfoBean siteInfoBean = null; //文件信息Bean v|?@k^Ms  
long[] nStartPos; //开始位置 'Kelq$dn#  
long[] nEndPos; //结束位置 68%aDs  
FileSplitterFetch[] fileSplitterFetch; //子线程对象
*4O=4F)x  
long nFileLength; //文件长度 Wzq W1<*`  
boolean bFirst = true; //是否第一次取文件 5C w( 4.  
boolean bStop = false; //停止标志 p^l#Wq5  
File tmpFile; //文件下载的临时信息 uH_KOiF  
DataOutputStream output; //输出到文件的输出流 '.}}k!#  
w7)pBsI  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） sA0Ho6  
public SiteFileFetch(SiteInfoBean bean) throws IOException zI88IM7/  
{ !E7gIqo  
siteInfoBean = bean; l9p  6I  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); o<g?*"TRh  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /%$Zm^8c  
if(tmpFile.exists ()) LUbhTc  
{ iUKjCq02  
bFirst = false; U#<d",I  
read_nPos(); YV>a 3  
} FT).$h~+4  
else +in)(a.  
{ ?pL|eS7  
nStartPos = new long[bean.getNSplitter()]; tX*@r  
nEndPos = new long[bean.getNSplitter()]; B=Hd:P|  
} ]&'!0'3`  
o.s'0xP]  
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} ;R$G.5h  
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public void run() &9jJ\+:7  
{ -:}vf?  
//获得文件长度 b,~'wm8:A  
//分割文件 IRW0.'Dn  
//实例FileSplitterFetch 2"0VXtv6  
//启动FileSplitterFetch线程 gI:g/ R  
//等待子线程返回 o:8ns m  
try{ L3]J8oEmU  
if(bFirst) ^&3vGu9  
{ hvt]VC]]  
nFileLength = getFileSize(); \e a*  
if(nFileLength == -1) deVd87;@7[  
{ }OkzP)(  
System.err.println("File Length is not known!"); lL}6IZ5sb  
} >=k7#av  
else if(nFileLength == -2) Q`CuZkP(  
{ 3G// _f  
System.err.println("File is not access!"); mR}8}K]L  
} Rtf<UhUn  
else u5CSx'h]  
{ I0-1
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for(int i=0;i<nStartPos.length;i++) a[ULSYEi  
{ '!>9j,BJ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <I,4Kc!  
} <3Ftq=  
for(int i=0;i<nEndPos.length-1;i++) E2hsSqsu=  
{ +Q&l}2  
nEndPos = nStartPos[i+1]; H
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} {/[@uMS_6]  
nEndPos[nEndPos.length-1] = nFileLength; +=WBH'  
} QW..=}pL  
} CKw-HgXG  
lw=kTYbq  
LcKc#)'EE  
//启动子线程 \Y xG  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; l@Lk+-[D  
for(int i=0;i<nStartPos.length;i++) +m_.?V6  
{ o HK  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), HB9"T5Pd*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &0 QUObK  
nStartPos,nEndPos,i); `(W"wC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F"Dr(V  
fileSplitterFetch.start(); RXRbW%b  
} 9FEhl~&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZfM]A)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); COi15( G2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", m?-)SA  
nEndPos = " + nFileLength); w+m7jn!$  
// fileSplitterFetch[nPos.length-1].start(); Yjg$o:M  
% :G78.  
Ehy(;n)\  
//等待子线程结束 jLFaf#G]  
//int count = 0; ;&lXgC^*  
//是否结束while循环 8YSvBy  
boolean breakWhile = false; `!8\
|/  
|\bNFnn(  
AyJl
:aN^  
while(!bStop) 5a |R  
{ 1dD%a91  
write_nPos(); MpKXC  
Utility.sleep(500); 6@aH2+4+  
breakWhile = true; CI+)0=`<1B  
x.t<@y~  
8] LF{Obz[  
for(int i=0;i<nStartPos.length;i++) ~'*23]j  
{ 5?3v;B6  
if(!fileSplitterFetch.bDownOver) E2Sj IR}  
{
[w](x  
breakWhile = false; CfOyHhhKX  
break; X8}r= K~  
} <v ub Q4  
} c|%5SA  
if(breakWhile) %>&~?zrq  
break;  H_g
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_9oKW;7f7  
6I
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//count++; ' !huU
 
//if(count>4) hLfWDf*T|  
// siteStop();  2  
} _Q:ot'(~0-  
P]"@3Z&w  
=Vh]{y~$  
System.err.println("文件下载结束！"); OL
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} d{TcjZ  
catch(Exception e){e.printStackTrace ();} +@$VJM%^7b  
} hl[<o<`Q  

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/{({f?k<\/  
//获得文件长度 %n]jsdE^|  
public long getFileSize() J^t0M\  
{ Qfeu3AT  
int nFileLength = -1; [,&g46x22  
try{ t:dvgRJt*  
URL url = new URL(siteInfoBean.getSSiteURL()); QAI=nrlp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [voc_o7AI  
httpConnection.setRequestProperty("User-Agent","NetFox"); S|d /?}C|e  
g=KK PSK  
hW~% :v  
int responseCode=httpConnection.getResponseCode(); '+_-r'2  
if(responseCode>=400) Z9mI%sC[(  
{ j gV^{8qG  
processErrorCode(responseCode); 02 FLe*zQ  
return -2; //-2 represent access is error 06NiH-0O  
} )fXxkOd  
5hqXMs  
ko.%@Y(=  
String sHeader; `B?+1Gv  
@MQfeM-@  
:~s"]*y  
for(int i=1;;i++) y**L^uvr  
{ '>OEQU5-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )1 @v<I  
//Utility.log(in.readLine()); $_%  
sHeader=httpConnection.getHeaderFieldKey(i); +VIEDV+   
if(sHeader!=null) [p\xk{7Y  
{ p;[.&oJ  
if(sHeader.equals("Content-Length")) H/f}tw  
{ ,>g(%
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K[SzE{5=P  
break; ldG8hK  
}
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} G>Bgw>#_  
else B'Nvl#  
break; FpttH?^  
} @#"K6  
} :A#'8xE/  
catch(IOException e){e.printStackTrace ();} b5p;)
#  
catch(Exception e){e.printStackTrace ();} }+ W5Snx  
Jbima>  
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Utility.log(nFileLength); +vFqHfmP  
-vT$UP  
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return nFileLength; +=`w  
} aSm</@tO&  
yokZ>+jb  
\#h=pz+jb  
//保存下载信息（文件指针位置） r
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private void write_nPos() hAi'|;g  
{ fk#Ggp<  
try{ Ty 6XU!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); aF=;v*  
output.writeInt(nStartPos.length); O[ans_8  
for(int i=0;i<nStartPos.length;i++) PC=s:`Y}R  
{ PVKq&Q?  
// output.writeLong(nPos); N}|1oQkjf  
output.writeLong(fileSplitterFetch.nStartPos); PHsM)V+  
output.writeLong(fileSplitterFetch.nEndPos); NFU=PS$  
} G4F~V't  
output.close(); D-e^b'l  
} 4!glgE
E*  
catch(IOException e){e.printStackTrace ();} k \t6b1.M  
catch(Exception e){e.printStackTrace ();} d76C]R5L  
} Y5>'(A>  
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Xp^>SSt:4  
//读取保存的下载信息（文件指针位置） B]D51R\}VE  
private void read_nPos() X bV?=  
{ -r_Pp}s  
try{ XF4NRs  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); RvW>kATb_F  
int nCount = input.readInt(); m[5ed1+  
nStartPos = new long[nCount]; lKirc2  
nEndPos = new long[nCount]; Qe<c@i"  
for(int i=0;i<nStartPos.length;i++) Q
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{ IetV]Ff6  
nStartPos = input.readLong(); KueI*\ p  
nEndPos = input.readLong(); iow8H' F  
} ,g)9ZP.F  
input.close(); w68VOymD/  
} is-{U?-  
catch(IOException e){e.printStackTrace ();} v2#qs*sW8  
catch(Exception e){e.printStackTrace ();} Zfr?(y+3  
} la!rg#)-X  
vCR\lR+  
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private void processErrorCode(int nErrorCode) nYY'hjZ  
{ aG1[85:,\i  
System.err.println("Error Code : " + nErrorCode); c_2kHT  
} H%c{ }F  
DB1
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;UjP0z
  
//停止文件下载 `^E(P1oJ3  
public void siteStop() PI")
^`  
{ 4gm(gY>[  
bStop = true; #KSB%  
for(int i=0;i<nStartPos.length;i++) In4T`c?kQ  
fileSplitterFetch.splitterStop(); "_&HM4%!  
=7("xz%  
@}N;C..Y$  
} [C~{g#  
} jr5x!@rb  
//负责部分文件的抓取 _nnl+S>K  
**FileSplitterFetch.java LYiz:cQh  
*/ zPoIs@  
package NetFox; ~oBSf+N  
KWV{wW=-  
[[u&=.Au  
import java.io.*; 8<ri"m,  
import java.net.*; Ib4 8`  
$VJ=A<  
>
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public class FileSplitterFetch extends Thread { 8>jd2'v{  
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0r\hX6 k  
String sURL; //File URL Ol@ YSkd  
long nStartPos; //File Snippet Start Position \+w -{"u$  
long nEndPos; //File Snippet End Position K31rt-IIt  
int nThreadID; //Thread's ID aKCXV[PO  
boolean bDownOver = false; //Downing is over A&0sD}I\K  
boolean bStop = false; //Stop identical Uz!cVs?-  
FileAccessI fileAccessI = null; //File Access interface 8:A6Ew&\]O  
mY1$N}8fm  
-r82'3]  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ~#~Kxh  
{ l>9ZAI\^  
this.sURL = sURL; m;LeaD}0  
this.nStartPos = nStart; HPj7i;?O  
this.nEndPos = nEnd; f&>Q6 {*]  
nThreadID = id; B6Tn8@O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (iiyptJ  
} tL4xHa6v]  
'x10\Q65[  
\bb,gRfP  
public void run() !$+J7\&7p  
{ dDk<J;~jGJ  
while(nStartPos < nEndPos && !bStop) Lp/]iZ@  
{ 7QRtNYo#\  
(sn|`k3I  
7[V'3  
try{ Z)(C7,Xu  
URL url = new URL(sURL); /T*]RO4%>]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *Mqg_} 0Y  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;z7iUke0%  
String sProperty = "bytes="+nStartPos+"-"; 'bg%9}  
httpConnection.setRequestProperty("RANGE",sProperty); 9W7H",
wR  
Utility.log(sProperty); B)
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InputStream input = httpConnection.getInputStream(); o*QhoDjc  
//logResponseHead(httpConnection); ^f1}:g  
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byte[] b = new byte[1024]; e:
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int nRead; _W*
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,[^P
 
{ X;p,Wq#D'  
nStartPos += fileAccessI.write(b,0,nRead); 4//Ww6W:  
//if(nThreadID == 1) s4}}MV3X  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I)O-i_}L&K  
} cEw/F0  
]0dp^%  
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Utility.log("Thread " + nThreadID + " is over!"); GYv2^IB:  
bDownOver = true; !=0N38wA  
//nPos = fileAccessI.write (b,0,nRead); x<=+RYz#^:  
} eA_1?j]E3  
catch(Exception e){e.printStackTrace ();} <  v_?}  
} 3!CI=(^IY  
} GI7CZ  
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M>_S%V4a  
//打印回应的头信息 t/S~CIA  
public void logResponseHead(HttpURLConnection con) mnXaf)"  
{ H,=??wN  
for(int i=1;;i++) "$:nz}  
{ ^ tm,gh  
String header=con.getHeaderFieldKey(i); e v?Hz8Q;(  
if(header!=null) ">voi$Kzey  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :ZU  
Utility.log(header+" : "+con.getHeaderField(header)); OH*[
  
else m.EWYO0XQ  
break; 
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} })bTQj7  
} 0 x"3  
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public void splitterStop() c6dL S  
{ it>FG9hVo  
bStop = true; K )1K ]  
} KS1Z&~4  
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} nXk<DlTws  
^ ,U9N  
VL&E2^*E  
/* B {f&'1pp/  
**FileAccess.java xhj A!\DS  
*//文件访问(定位，写) >Ex\j?  
package NetFox; N6EH  
import java.io.*; 2|kx:^D p  
qA#!3<  
XNf%
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public class FileAccessI implements Serializable{ k P>G4$e_v  
X@5!I+u\L  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 XQ%*U=)s  
RandomAccessFile oSavedFile; P
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long nPos; C8DZ:3E$c  
4)*8&  
PDzVXLpC  
public FileAccessI() throws IOException s==gjA e:  
{ [9~Bau  
this("",0); }*hY#jo1  
} @T|mHfQ8  
<<@$0R
W  
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public FileAccessI(String sName,long nPos) throws IOException g(>;Z@Y  
{ 8BhLO.(<O  
oSavedFile = new RandomAccessFile(sName,"rw"); 8 POrD8B  
this.nPos = nPos; 7y&Fb  
oSavedFile.seek(nPos); BPIp3i  
} 8AOJ'~$  
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P'KaWu9z  
public synchronized int write(byte[] b,int nStart,int nLen) KaZ*HPe(  
{ O+@"l$;N  
int n = -1; {Fta4D_1N  
try{ 8h78Zb&[  
oSavedFile.write(b,nStart,nLen); ^EN_C<V;"d  
n = nLen; 5 b( [1*  
} q<>LK  
catch(IOException e) 6K5KZZG  
{ 1%G<gbHpI  
e.printStackTrace (); /KO!s,Nk  
} s{2BG9s
 

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#^"\WG7{  
return n; yrs![u  
} :\NqGS=<  
(?72 vCc  
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} sT?Qlj'Zd  
sf2_x>U1  

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/* :G?"BL5vP  
**SiteInfoBean.java C=t:0.:PJ  
*/ -P]J:7*0?\  
package NetFox; M3Q#=yy$D$  
!t3)j>h:  
403%~  
public class SiteInfoBean { - (VV  
`Yn^ -W  
vHZw{'5y  
private String sSiteURL; //Site's URL K8$Hg:Ky-/  
private String sFilePath; //Saved File's Path @sO*O4os>  
private String sFileName; //Saved File's Name \5BI!<  
private int nSplitter; //Count of Splited Downloading File
U{q6_z|c  
aEW Z*y  
2[}^ zTtA  
public SiteInfoBean() 9TjAEeU  
{//nSplitter的缺省值为5 .Kv>*_
_-Q  
//default value of nSplitter is 5 ?>N82#9Q  
this("","","",5); ?"$W=*P\o  
} 4d)w2t?H%  
;``*]tY$  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) xAMj16ZF  
{ iNZ'qMH22  
sSiteURL= sURL; @tdX=\[~  
sFilePath = sPath; g^26Gb.  
sFileName = sName; ?D/r1%Z  
this.nSplitter = nSpiltter; iOm~
 
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2-ev7:  
} c@1C|  
8c\mm 0n  
L01R.3Z+  
public String getSSiteURL() `<zaxO  
{ K2$mz  
return sSiteURL; @I2m4Q{O  
} LyhLPU0^q  
-@b&qi7&S  
MeW8aLr  
public void setSSiteURL(String value) >|KfO>  
{ wb2N$Ew=  
sSiteURL = value; o^wj_#ai$  
} 1!/cd;{B  
CsS0(n(x  
A0#
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public String getSFilePath() WM}:%T-  
{ )zlksF  
return sFilePath;
d~tG#<^`  
} k[R/RhHQ,  
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"Nj(0&  
public void setSFilePath(String value) ~O?Gi 4^Yg  
{ 81V,yq]  
sFilePath = value; J)Dw`=O0n  
} >^ 0JlL`XG  
cBb!7?6(  
fz31di9$  
public String getSFileName() B9KY$^J  
{ 5F+5J)h  
return sFileName; q]=.Aik  
} )5_GJm&R9  
t*5d'aE`/  
Na=9ju  
public void setSFileName(String value) VG*BAFs  
{ -v8Jn#f  
sFileName = value; (P~Jzp9u  
} Gy.<gyK9  
k{Vc5F  
`0uKJFg  
public int getNSplitter() z{bMW^F  
{ ]|<PV5SY3.  
return nSplitter; V:9|9$G  
} daE/v.a4|  
1GN>,Lb:o  
PvBx<i}A  
public void setNSplitter(int nCount) +2O('}t  
{ m<IPi <  
nSplitter = nCount; l<<0:
~+q  
} 
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} w-FZ`OA`D  
9*GwW&M%1_  
AT}}RE@vq  
/* 5Qd |R  
**Utility.java 5)' _3r  
*/ yBE1mA:x7:  
package NetFox; f)H6 nl7r  
~mOGNf?f  
.3?'+KZ,  
public class Utility { 0aQtJ0e16  
_s><>LH~  
D@uw[;Xb5  
public Utility() `Gx"3ZUn  
{ j|FGb:  
+P/"bwv0  
M$ep.<Z1|  
} .{k(4_Q?I  
TP{lt6wws(  
//线程睡眠 a3?Dtoy'  
public static void sleep(int nSecond) -b~MQ/,2  
{ ih.UzPg  
try{ z{d],M  
Thread.sleep(nSecond); /O|!Sg{  
} r(yJE1Wz  
catch(Exception e) QtJe){(z+  
{ <89@k(\ /  
e.printStackTrace (); (aVsp*E  
} $5GvF1  
} E}lU?U5i  
a({qc0+UK  
//日志 _DMj)enH"  
public static void log(String sMsg) c=I!?a"  
{ cBmo#:>'  
System.err.println(sMsg); 0!9vGs  
} g-pDk*|I,Q  
,r{*o6  
4U<'3~RN  
public static void log(int sMsg) <]/`#Xgh  
{ m}:";>?#  
System.err.println(sMsg); 2n?\tOm(V  
} &~pj)\_  
} IE$x2==)  
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@
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/* HQ7-,!XO  
**TestMethod.java vF;6Y(h>  
*/ tirw{[X0n  
package NetFox; [T"oqO4%]  
^8.R 'Yq  
Tr)a6Cf  
public class TestMethod { (6u<w#u  
W0tBF&E"  
9r+`j  
public TestMethod() e~$MIHBY]  
{ ///xx/weblogic60b2_win.exe $^IuE0.  
try{ H|0B*i@81  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); JnhHV(H  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); o%h\55S  
SiteFileFetch fileFetch = new SiteFileFetch(bean); B5#a 4G.  
fileFetch.start(); uQ&&?j  
} -}{\C]%  
catch(Exception e){e.printStackTrace ();} cmt3ceCb  
.Y_RI&B!L  
tH5f;mY,  
} \@pl:Os  
$LAaG65V  
2c5>0f  
public static void main(String[] args) TMKemci  
{ 'gUHy1p  
new TestMethod(); vnk"0d.  
} p!' "hx  
} I-kM~q_  
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