http断点续传简单实现（java)

/* :lp V  
**SiteFileFetch.java
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*/ ?9:~d#p  
package NetFox; 2D'$  
import java.io.*; bt0Q6v5  
import java.net.*; ,];QzENw  
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5HW'nhE  
public class SiteFileFetch extends Thread { <g{d>j  
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SiteInfoBean siteInfoBean = null; //文件信息Bean n
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long[] nStartPos; //开始位置 NrWgaPO)i  
long[] nEndPos; //结束位置 #;F*rJ[XY  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )o_Pnq9_  
long nFileLength; //文件长度 !ZzDSQ;  
boolean bFirst = true; //是否第一次取文件 K7}]pk,AG  
boolean bStop = false; //停止标志 uN9J?j*ir  
File tmpFile; //文件下载的临时信息 TX$4x~:  
DataOutputStream output; //输出到文件的输出流 3s$vaV~(a  
9<-7AN}Z  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） nn{PhyK  
public SiteFileFetch(SiteInfoBean bean) throws IOException _?c7{  
{ 4-~S"T8<u  
siteInfoBean = bean; roHJ$~q?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); oS#PBql4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {6gY6X-R  
if(tmpFile.exists ()) Ql{:H5  
{ "aJfW  
bFirst = false; Q;0g  
read_nPos(); 3\0,>L9ET@  
} }BJR/r  
else D> EN:_v  
{ P8n |MN  
nStartPos = new long[bean.getNSplitter()]; ,]_<8@R  
nEndPos = new long[bean.getNSplitter()]; p\ _&  
} T!Z).PA#  
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} 9UE)4*5  
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public void run() %>!$eCX  
{ ) S,f I  
//获得文件长度 I7Xm~w!{qk  
//分割文件 =R
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//实例FileSplitterFetch K%WG[p\Eu  
//启动FileSplitterFetch线程 7L$\S[E  
//等待子线程返回 \,-e>  
try{ pMLTXqL  
if(bFirst) .1A/hAdU  
{ =a!_H=+4  
nFileLength = getFileSize(); \<W/Z.}/  
if(nFileLength == -1) cE+Y#jB  
{ vMeB2r<  
System.err.println("File Length is not known!"); ZFNg+H
/k  
} u{%dm5  
else if(nFileLength == -2) ;U]Ym48  
{ D/bF  
System.err.println("File is not access!"); ,qT+Vqpr{  
} f yhBfA:u  
else K2!GpGZu  
{ qw6i|JM%  
for(int i=0;i<nStartPos.length;i++) 't3&,:Y  
{ [K""6D  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); );=0cnr3  
} s|!lw  
for(int i=0;i<nEndPos.length-1;i++) lAJP X  
{ jAak,[~;  
nEndPos = nStartPos[i+1]; e)*-<AGwC  
} Y4{/P1F  
nEndPos[nEndPos.length-1] = nFileLength; }}u16x}*n  
} k\KI#.>  
} >.&E-1[+:  
XNQPyZ2@|b  
AfvIzsT0  
//启动子线程 \%|%C  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G|.6%-  
for(int i=0;i<nStartPos.length;i++) #&K?N  
{ DLD5>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PpezWo)9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), vC!B}~RG  
nStartPos,nEndPos,i); ^5rB/y,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _t?#
 
fileSplitterFetch.start(); ~'w]%rh!  
} fxknfgbg  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Q)2i{\GPVn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =buarxk  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", '9@AhiNV  
nEndPos = " + nFileLength); QzVoU |  
// fileSplitterFetch[nPos.length-1].start(); YT'olk  
U<I
]_]  
U88gJ[$  
//等待子线程结束 6 l7iX]  
//int count = 0; ToM1#]4  
//是否结束while循环 g9@H4y6fe=  
boolean breakWhile = false; BKKW3PT  
dF$&fo%  
/p$+oA+  
while(!bStop) `wKd##v'@  
{ Af Y]i  
write_nPos(); `APeS=< &  
Utility.sleep(500); cy0j>-z  
breakWhile = true; Hq#q4Y  
zx7A}rs3oX  
`PZcL2~E  
for(int i=0;i<nStartPos.length;i++) 6k`O  
{ \hI|I!sDWy  
if(!fileSplitterFetch.bDownOver) 6G7+&g`  
{ ng:B;; m  
breakWhile = false; PFjh]/=  
break; =HjC.h  
} Tly*i"[&  
} SvQ!n4 $  
if(breakWhile) 17#t7Yk  
break; Jk;dtLL}4  
&Gs/#2XQ  
$},_O8R  
//count++; N"s"^}M\  
//if(count>4) mC} b>\  
// siteStop(); wizLA0W  
} r6vI6|1  
$bl<mG%#9  
p %hv
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System.err.println("文件下载结束！"); ?-JW2 E"uT  
} m=rMx]k  
catch(Exception e){e.printStackTrace ();} q\xsXM  
} v^aI+p6  
zMh`Uqid  
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//获得文件长度 :+f6:3  
public long getFileSize() yVWt%o/  
{ cCs@[D#O1  
int nFileLength = -1; d)GR]^=r  
try{ o_a'<7\#i  
URL url = new URL(siteInfoBean.getSSiteURL()); eW;c 3<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r4Xaa<  
httpConnection.setRequestProperty("User-Agent","NetFox"); o)+C4f[G4  
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int responseCode=httpConnection.getResponseCode(); Kx02 2rgDU  
if(responseCode>=400) cN`P5xP'  
{ L@.Trso  
processErrorCode(responseCode); baGV]=j  
return -2; //-2 represent access is error w|f@sB>j  
} ^%O$7*  
<Ok7-:OxA  
}U?:al/m  
String sHeader; =^z*p9ZB  
*onVG5<  
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for(int i=1;;i++) 9Zr6 KA{  
{ +xQj-r)-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); R)-~5"}~  
//Utility.log(in.readLine()); @(IA:6GN  
sHeader=httpConnection.getHeaderFieldKey(i); 4lI&y<F  
if(sHeader!=null) n.Y45(@E  
{ `
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if(sHeader.equals("Content-Length")) -$I$zo  
{ EAHdt=8W{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9Y?``QBN  
break; 5%+epzy  
} E {UhM q7  
} .  LeS-  
else F^&@[k7WW  
break; DABV}@K"  
} uK0L>
  
} 9{0%M  
catch(IOException e){e.printStackTrace ();} c3WF!~1r  
catch(Exception e){e.printStackTrace ();} zXk^ugFy  
/ 2MhP=
,  
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Utility.log(nFileLength); #<G:&  
`5
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return nFileLength; %Vfr#j$
=  
} 58R.`5B  
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"
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//保存下载信息（文件指针位置） PmQeO*f+  
private void write_nPos() >^SQrB  
{ BZIU@^Q_Y[  
try{ GC|V>| tz#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); iFZ.a.NDc  
output.writeInt(nStartPos.length); OS1f}<  
for(int i=0;i<nStartPos.length;i++) _-2;!L#/  
{ !wC( ]Y  
// output.writeLong(nPos); /T2 v`Li  
output.writeLong(fileSplitterFetch.nStartPos); 5Rp mR  
output.writeLong(fileSplitterFetch.nEndPos); 8:2Vib$  
} uX6p^KNm5  
output.close(); ?v`24p3PC  
} JW"`i   
catch(IOException e){e.printStackTrace ();} C3~O6<,Jh  
catch(Exception e){e.printStackTrace ();} &UO/p/a
 
} b5?kgY  
V9cj  
h-
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//读取保存的下载信息（文件指针位置） x4,[5N"}YK  
private void read_nPos() 9P*f  
{ Pa"Kk9!o36  
try{ Yp\Y]pym  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =CO'LyG  
int nCount = input.readInt(); j%}9tM6[  
nStartPos = new long[nCount]; c4zGQoeH:  
nEndPos = new long[nCount]; olKM0K  
for(int i=0;i<nStartPos.length;i++) *;Cpz[N  
{ 3J8M0W  
nStartPos = input.readLong(); /. H(&  
nEndPos = input.readLong(); Ucz=\dO1  
} }PM7CZSq  
input.close(); 40z1Qkmaey  
} yCkX+{ki  
catch(IOException e){e.printStackTrace ();} Bn.5ivF3  
catch(Exception e){e.printStackTrace ();} \jZ)r>US"  
} 24wr=5p]Q  
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KOoV'YSC[(  
private void processErrorCode(int nErrorCode) 7Sh1QDYZ  
{ tKds|0,j|  
System.err.println("Error Code : " + nErrorCode); '&$zgK9T?  
} X&Sah}0V&  
8"p rWAN  
|:,`dQfw  
//停止文件下载 1H-~+lf  
public void siteStop() N#@v`S  
{ Sggl*V/q  
bStop = true;  ?$y/b}8  
for(int i=0;i<nStartPos.length;i++) mHa~c(x  
fileSplitterFetch.splitterStop(); -$49l  
"<f?.l\+  
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} ~Q5]?ZNX  
} b5ul|p  
//负责部分文件的抓取 J*m7 d4^  
**FileSplitterFetch.java &wN}<Ge6  
*/ Fc=6*.hy  
package NetFox; 4n1 g@A=y  
t;u)_C,bmP  
b `bg`}x  
import java.io.*; @ZrNV*&<  
import java.net.*; Hs{x Z:  
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public class FileSplitterFetch extends Thread { j`K0D65  
,?`kYPZ  
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String sURL; //File URL :_`Yrx5  
long nStartPos; //File Snippet Start Position (:h&c6'S)b  
long nEndPos; //File Snippet End Position =W>a~e]/  
int nThreadID; //Thread's ID T0.sL9  
boolean bDownOver = false; //Downing is over e E(+  
boolean bStop = false; //Stop identical "z=~7g  
FileAccessI fileAccessI = null; //File Access interface t:xTmK&vt  
8 qZbsZi4  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException OMd:#cWsQ  
{ ^(@]5
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this.sURL = sURL; MBnxF^c&P  
this.nStartPos = nStart; c#>:U,j
 
this.nEndPos = nEnd; C5jt(!pi  
nThreadID = id; 4W<[& )7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 A PrrUo  
} M 9NT%7Il  
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public void run() 66$hdT$  
{ B\% Gp}  
while(nStartPos < nEndPos && !bStop) G*~CB\K_  
{ Xq"Es  
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try{ 9[DlJ@T}  
URL url = new URL(sURL); J3B+WD]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z&=
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httpConnection.setRequestProperty("User-Agent","NetFox"); ?_v_*+b_  
String sProperty = "bytes="+nStartPos+"-"; gvL*]U7  
httpConnection.setRequestProperty("RANGE",sProperty); S,f#g?V  
Utility.log(sProperty); woF{O)~X  
)J2UNIgN  
~=<uYv?0s  
InputStream input = httpConnection.getInputStream(); Cv4nl7A'  
//logResponseHead(httpConnection); $iA:3DM07  
/CbiYm  
_lRIS_^;eE  
byte[] b = new byte[1024]; hzpl;Mj  
int nRead; (]10Z8"fJ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) '(ZT}N  
{ OYb:);o,iE  
nStartPos += fileAccessI.write(b,0,nRead); Y"nz l]T  
//if(nThreadID == 1) I]3!M`IMG  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); CkNh3'<wg  
} @W~aoq6  
3II*NANeg  
I :b
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Utility.log("Thread " + nThreadID + " is over!"); ^upd:q  
bDownOver = true; fN:FD`  
//nPos = fileAccessI.write (b,0,nRead); S@y?E}  
} {A5$8)nl|  
catch(Exception e){e.printStackTrace ();} ;lt8~ea  
} uD[T l  
} 77wod}h!:  
,DEcCHr,  
^g"p}zf L"  
//打印回应的头信息 Vi
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public void logResponseHead(HttpURLConnection con) QjYw^[o  
{ v yt|x5  
for(int i=1;;i++) <'BsQHI  
{ .CNwuN\  
String header=con.getHeaderFieldKey(i); FPPl^  
if(header!=null) rEbH<|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); .'h^  
Utility.log(header+" : "+con.getHeaderField(header)); oiD{Z  
else ml!c0<  
break; G|||.B8  
} (uC@cVkP  
} 6z:/ma^  
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public void splitterStop() ^+k= ;nl  
{ `tXd?E/e  
bStop = true; %|>D{q6C  
} ]Zc\si3i&  
"5?1S-Vl  
/}iBrMD{[  
} fr$6&HDZ9  
;vbMC74J#  
6Ypc]ym=J  
/* ] ;CJ6gM~  
**FileAccess.java 8!@}\6qM  
*//文件访问(定位，写) <:mK&quf  
package NetFox; <(yAat$H  
import java.io.*; Q("4R  
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t~44ub6GN`  
public class FileAccessI implements Serializable{
/-WmOn*  
4gUx#_AaG  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 "/2kf)l{4  
RandomAccessFile oSavedFile; 2iO{*cB
 
long nPos; kg,\l9AM  
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&] xtx>qg<  
public FileAccessI() throws IOException )r)ZmS5O  
{ 8#o2qQ2+  
this("",0); \w(0k^<7  
} Cb.M  
*/K]sQZa  
og&h$<uOZt  
public FileAccessI(String sName,long nPos) throws IOException LnsYtkbr  
{ N.ZuSkR
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oSavedFile = new RandomAccessFile(sName,"rw"); 2"%f:?xV{  
this.nPos = nPos; ` K0PLxSv  
oSavedFile.seek(nPos); ]&`
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} ]mgpd}Y  
ASr@5uFR  
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public synchronized int write(byte[] b,int nStart,int nLen) >.G#\w  
{ 7u5H o`  
int n = -1; 3f~znO  
try{ 2iOYC0`!  
oSavedFile.write(b,nStart,nLen); '#.D
`9YI<  
n = nLen; WN#2<XjG  
} ya,-Lt  
catch(IOException e) T=@Ygjk  
{
/WLZyT2  
e.printStackTrace (); \=&Z_6Mu  
} Gi2Fjq/Y  
*Tr{a_{~C  
8F's9c,  
return n; G-;EB  
} ?du*ITi
m  
' ~fP#y  
v\?l+-A?y  
} ;cp||uO  
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82?LZ?!PD  
/* @L0)k^:  
**SiteInfoBean.java >g@@ yR,  
*/ 8s-X H  
package NetFox; `0!%jz=  
4T v=sP  
rq}xuSFI  
public class SiteInfoBean { oEj$xm_}  
aVr=7PeF  
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private String sSiteURL; //Site's URL jc#gn&4C  
private String sFilePath; //Saved File's Path 9RkNRB)8  
private String sFileName; //Saved File's Name t)~$p#NS  
private int nSplitter; //Count of Splited Downloading File V{x[^+w7X~  
tYSfeU  
GZY:EHuz[  
public SiteInfoBean() .f>7a;V?}  
{//nSplitter的缺省值为5 {eQijW2Z3  
//default value of nSplitter is 5 lQm7`+  
this("","","",5); 8LXK3D}?3  
} )V*`(dn'zm  
?U1Nm~'UZ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) CJs ~!ww  
{ {G<1.  
sSiteURL= sURL; [qkc6sqo  
sFilePath = sPath; (XFF}~>B.  
sFileName = sName; }nO%q6|\V  
this.nSplitter = nSpiltter; 2+g'ul`  
}jdmeD:  
Cn5;h(r  
} r)Ml-r=  
_u6MSRX[6$  
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public String getSSiteURL() =ReSlt  
{ u|D L?c>W  
return sSiteURL; E]r<t#  
} ,^eOw
WV  
U%;E:|  
A* Pz-z>z  
public void setSSiteURL(String value) 0W+RVp=TL1  
{ [8oX[oP  
sSiteURL = value; wL6G&6]</W  
} ;ZP!:,  
Z/4bxO=m  
"s(|pQh;  
public String getSFilePath() ~lqNWL^l  
{ j7NOYm5N  
return sFilePath; N3oa!PE  
} av:%wJUl,$  
ld 1[Usaq  
<JvYCWX`  
public void setSFilePath(String value) cjd-B:l  
{ X;#Ni}af  
sFilePath = value; 7-\wr^ll3  
} y>d`cRy  
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public String getSFileName() :lm
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{ ?@MWV  
return sFileName; Y@T$O<*  
} '0&HkM{ D  
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%kgT=<E'  
public void setSFileName(String value) ;M\Cw.%![  
{ 5Kk}sxol  
sFileName = value;
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} +"~*L,ken0  
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1(%6X*z  
public int getNSplitter() Ub4)x  
{ vu*9(t)EC  
return nSplitter; [lK`~MlQ  
} K2V?[O#  
t?=V<Yd1  
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public void setNSplitter(int nCount) $~?)E;S  
{ ^v:XON<  
nSplitter = nCount; Ay%]l| Gm  
} lTtc#  
} C+mPl+}w  
D}-HWJQA3  
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/* !FB2\hiM  
**Utility.java 1CV?  
*/ 9[`\ZGWD  
package NetFox; f2v~
: u  

{>TAnb?n  
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public class Utility { A.r.tf}:  
m2ph8KC  
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public Utility() fWF!%|L  
{ F*NHy.Y  
(/t{z=  
vy>(?[  
} h96<9L  
r]wy-GT  
//线程睡眠 y S<&d#:"  
public static void sleep(int nSecond) q 1u_r  
{ >N}+O<Fc  
try{ Kf)$/W4  
Thread.sleep(nSecond); 3Gw*K-.  
} C/ ]Bx  
catch(Exception e) ;$qc@)Uwp  
{ ?}u][akM  
e.printStackTrace (); [d>2F  
} H$ :BJ$x@  
} !thFayq  
Z0wH%
o\  
//日志 T/J1 b-  
public static void log(String sMsg) oDGBC  
{  Lu[Hz8  
System.err.println(sMsg); v^[!NygShs  
} l SuNZYaO  
DLe>EU;vS  
th0>u.hJ  
public static void log(int sMsg) >km$zfM2-  
{ pNu?DF{ 3  
System.err.println(sMsg); ,I,Zl.5  
} aFh'KPhe  
} G,(Xz"`,  
i"E_nN"V  
"ZmxHMf  
/* UCo<ie\V  
**TestMethod.java C?6q]k]r  
*/ -:b<~S[  
package NetFox; 2t=&h|6EW  
2{g&9  
{WeRFiQ?-  
public class TestMethod { : >$v@d  
X3ZKN
;  
?b(DDQMf  
public TestMethod() " ;\EU4R  
{ ///xx/weblogic60b2_win.exe +hH7|:JQ  
try{ &@PAv5iNf  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); iA'p!l|P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 'p%w_VbI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =H}}dC<)  
fileFetch.start(); YC*`n3D|'  
} !Uhcjfq`e  
catch(Exception e){e.printStackTrace ();} X-j<fX_  
y35e3  
1d&Q E\2}  
} qs9r$o.\l  
~BBh4t&  
%fh-x(4v  
public static void main(String[] args) Cth<xn(Q  
{ NpGz y`&b  
new TestMethod(); |m$]I4Jr  
} PK_2  
} s:tWEgZk?  
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