http断点续传简单实现（java)

/* /;TD n>lq  
**SiteFileFetch.java
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*/ ,9:v2=C_  
package NetFox; YS9)%F=X  
import java.io.*; ciH
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import java.net.*; cw BiT  
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public class SiteFileFetch extends Thread { q<g!bW%  
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SiteInfoBean siteInfoBean = null; //文件信息Bean '~6l 6wi  
long[] nStartPos; //开始位置 +I~U8v-  
long[] nEndPos; //结束位置 7z&^i-l.  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 G~lnX^46"  
long nFileLength; //文件长度 [/cJc%{N  
boolean bFirst = true; //是否第一次取文件 {6*UtG  
boolean bStop = false; //停止标志 G|$n,X1O(  
File tmpFile; //文件下载的临时信息 \ ]h$8JwV  
DataOutputStream output; //输出到文件的输出流 (n{!~'3  
^
6,}*@  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^[ >  
public SiteFileFetch(SiteInfoBean bean) throws IOException wrt^0n'r)c  
{ BnLE+
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siteInfoBean = bean; @8GW?R  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); n*fsdo~  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); CpF&Vy K  
if(tmpFile.exists ()) `]:&h'  
{ }fKpih  
bFirst = false; %]i("21  
read_nPos(); ,t_Fo-i7vI  
} |F#L{=B  
else X>y6-%@  
{ O(QJiS  
nStartPos = new long[bean.getNSplitter()];  =:-x;  
nEndPos = new long[bean.getNSplitter()]; @z)_m!yV1  
} GT"gB$Mh  
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h .$3jNU  
} B}y-zj;T  
%,M(-G5j;  
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public void run() "Q~-C|x  
{ #E( n  
//获得文件长度 bJE$>  
//分割文件 y$e'-v  
//实例FileSplitterFetch <2a7>\74E0  
//启动FileSplitterFetch线程 3%W R  
//等待子线程返回 }~RH!Q1  
try{ -IB~lw
 
if(bFirst) "K8<X  
{ YbrsXp"  
nFileLength = getFileSize(); v&EHp{8Qd  
if(nFileLength == -1) Nz&J&\X)tD  
{ P:")Qb2  
System.err.println("File Length is not known!"); MyOdWD&7  
} @"m? #  
else if(nFileLength == -2) AdtAc$@xK  
{ 7='M&Za  
System.err.println("File is not access!"); In)#`E` g.  
} 7 C5m#e3  
else av1*i3  
{ ;q&>cnLDR  
for(int i=0;i<nStartPos.length;i++) $siiG|)C1  
{ ,OLN%2Sq  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u=I>DEe@c  
} X}yEMe{T  
for(int i=0;i<nEndPos.length-1;i++) 3`&2-  
{ R4"g? e  
nEndPos = nStartPos[i+1]; u8*Uia*vwH  
} :_tsS)Q2m  
nEndPos[nEndPos.length-1] = nFileLength; EY(@R2~#J  
} ?<Dinq  
} &Q^M[X  
\HDRr*KO  
aT#R#7<Eg  
//启动子线程 ,c6ID|\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; p3*}!ez4  
for(int i=0;i<nStartPos.length;i++) 74%

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{ 3_IuK6K2  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }`yIO"{8n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), un[Z$moN"  
nStartPos,nEndPos,i); )L`0VTw'M  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z@cL<.0CE  
fileSplitterFetch.start(); OFCOMM  
} "7RQrz  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Fk>
/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (?&X<=|"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", z
48,{H6h  
nEndPos = " + nFileLength); LZyUlz  
// fileSplitterFetch[nPos.length-1].start(); 0vUX^<  
-ny[Lh^b  
)k3zOKZ;  
//等待子线程结束 {y'c*NS  
//int count = 0; y1/$dn  
//是否结束while循环 p,@_A'  
boolean breakWhile = false; (eN\s98)/  
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while(!bStop) w:&m_z#M  
{ cxrUk$f  
write_nPos(); cgm]{[
f  
Utility.sleep(500); d)(61  
breakWhile = true; nvxftbfE^D  
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for(int i=0;i<nStartPos.length;i++) 4)-LlYS_d<  
{ Sq}hx  
if(!fileSplitterFetch.bDownOver) *8fnxWR  
{ #5N#^#r"  
breakWhile = false; WtFv"$V  
break; FlRbGg^  
} a84^"GH7  
} "N"9PTX  
if(breakWhile) n!&DLB1z  
break; P6zy<w  
7<oLe3fbM  
 Jt.dR6,  
//count++; oJUVW"X6  
//if(count>4) *;(
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// siteStop(); hJ>{`Tw  
} jtV{Lf3<  
0~H(GG$VH  
jnYFA[Ab  
System.err.println("文件下载结束！"); OOGqtA;  
} ]YQlCx`  
catch(Exception e){e.printStackTrace ();} kV(}45i]s  
} ~#&bDot  
vX]\Jqy  
zJOjc/\  
//获得文件长度 ZTW
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public long getFileSize() * 'WzIk
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{ 5u MP31  
int nFileLength = -1; _y#t[|}w  
try{ ><viJ$i  
URL url = new URL(siteInfoBean.getSSiteURL()); "@RLS~Ej  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); su
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httpConnection.setRequestProperty("User-Agent","NetFox"); {v}f/cu  
)
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int responseCode=httpConnection.getResponseCode(); Y'&A~/Adf  
if(responseCode>=400) Qa~o'  
{ _|bIl%W;\'  
processErrorCode(responseCode); M%7{g"J*  
return -2; //-2 represent access is error -~~"}u  
} ykH?;Xu  
^]3Y11sI  
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String sHeader; w?d~c*4+  
,o& &d.  
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for(int i=1;;i++) !jL|HwlA  
{ w,cfSF;=tC  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Q<3=s6@T  
//Utility.log(in.readLine()); +VkhM;'"C  
sHeader=httpConnection.getHeaderFieldKey(i); $NC1>83  
if(sHeader!=null) XZYpU\K  
{ ;|6kFBGC"+  
if(sHeader.equals("Content-Length")) BoE;,s>]NW  
{ o7)<pfif  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^E*W B~  
break; G.OAzA13!t  
} v=
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} R5c Ya  
else /L\
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break; D::$YR ~R  
} kRo dC(f @  
} [`nY/g:  
catch(IOException e){e.printStackTrace ();} o^hI\9  
catch(Exception e){e.printStackTrace ();} ! /;@kXN
 
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Utility.log(nFileLength); e6f:@ O?  
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return nFileLength; 47>IT  
} kY*3)KCp  
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<3C~<  
//保存下载信息（文件指针位置） $zS0]@Dj  
private void write_nPos() #va|&QBZxM  
{ ^j&'2n@9a  
try{ :9un6A9JS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |g<
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output.writeInt(nStartPos.length); Jlw%t!Kx  
for(int i=0;i<nStartPos.length;i++) [ fvip_Pt  
{ KdY3  
// output.writeLong(nPos); i
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output.writeLong(fileSplitterFetch.nStartPos); "D0:Y(\  
output.writeLong(fileSplitterFetch.nEndPos); qOy3D~  
} !T;*F%G9  
output.close(); gM_z`H5[!  
} "Y0:Y?Vz"  
catch(IOException e){e.printStackTrace ();} QWVH4rg  
catch(Exception e){e.printStackTrace ();} V#8]io  
} v Yt-Nx  
E +\?|q !T  
F[PIo7?K  
//读取保存的下载信息（文件指针位置） \`?#V xz  
private void read_nPos() ~XAtt\WS  
{ jO xH'1I  
try{ ^.bYLF  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); [P,YW|:n  
int nCount = input.readInt(); z d 9Gi5&  
nStartPos = new long[nCount]; %gj's-!!  
nEndPos = new long[nCount]; G8xM]'y  
for(int i=0;i<nStartPos.length;i++) [pMJ9 d$  
{ ?DPNa  
nStartPos = input.readLong(); 9>~UqP9  
nEndPos = input.readLong(); dm3cQ<
0  
} H
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input.close(); V[D[MZ  
} _Eq*  
catch(IOException e){e.printStackTrace ();} |k5uVhN  
catch(Exception e){e.printStackTrace ();} ]{0R0Gr94  
} O8BxXa@5  
&sbA:xZBA  
?DP]#9/4  
private void processErrorCode(int nErrorCode) $ijWwrh  
{ B ;Zsp  
System.err.println("Error Code : " + nErrorCode); ^bpxhf x  
} )@DT^#zR  
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3md yY\+&  
//停止文件下载 F 7+Gt Ed  
public void siteStop() .<JD'%?"  
{ uS :3Yo  
bStop = true; 1M&n=s _  
for(int i=0;i<nStartPos.length;i++) }>:v  
fileSplitterFetch.splitterStop(); =IBdnEz:M  
,=KJ7zIK?  
[~$Ji&Dd  
} "kyy>H9)  
} 1G/bqIMg63  
//负责部分文件的抓取 %XGwQB$zk8  
**FileSplitterFetch.java n y6-_mA]  
*/ (bH*i\W  
package NetFox; U(5(0r  
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:w_J/k5Zd  
import java.io.*; hNXP-s  
import java.net.*; e"en ma\_  
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public class FileSplitterFetch extends Thread { `T $lTP  
qe!`LeT#  
rC~hjViG.  
String sURL; //File URL ~X;r}l=k<  
long nStartPos; //File Snippet Start Position fx|$(D@9  
long nEndPos; //File Snippet End Position SZJ~ktXC-V  
int nThreadID; //Thread's ID u>:sXm
 
boolean bDownOver = false; //Downing is over Ni IX^&N1  
boolean bStop = false; //Stop identical vW6Pf^yJ  
FileAccessI fileAccessI = null; //File Access interface Y}(#kqh>  
(PU0\bGA  
|;{^Mci%  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException
%tM]|!yw  
{ /Kb7#uq  
this.sURL = sURL; En3Q%  
this.nStartPos = nStart; PIP2(-{ai  
this.nEndPos = nEnd; %,%s09tO  
nThreadID = id; &k(t_~m>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ch,<4E/c[R  
} 1R9hA7y&,/  
" M8j?  
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public void run() 9ZUG~d7_  
{ tDFN *#(  
while(nStartPos < nEndPos && !bStop) X4*{CM  
{ oH!sJ&"#_  
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try{ a^i`DrX  
URL url = new URL(sURL); ZN5\lon|Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); OM{-^  
httpConnection.setRequestProperty("User-Agent","NetFox"); F6Zl#eL  
String sProperty = "bytes="+nStartPos+"-"; 3JEH sYxs  
httpConnection.setRequestProperty("RANGE",sProperty); y.5mYQA4=[  
Utility.log(sProperty); <=n$oMO  
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ULMG"."IH  
InputStream input = httpConnection.getInputStream(); +pc_KR  
//logResponseHead(httpConnection); G+AD &EHV  
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byte[] b = new byte[1024]; r Y|'<$wvg  
int nRead; R+8+L|\wHv  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |f'U_nE#R/  
{ }qT @.  
nStartPos += fileAccessI.write(b,0,nRead); $4'I3{$  
//if(nThreadID == 1) 3SVI|A5(d  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =A9>Ej/  
} e{U`^ao`F8  
9c8zH{T_{  
|M`B  
Utility.log("Thread " + nThreadID + " is over!"); PHi'&)|  
bDownOver = true; wKe^5|Rr  
//nPos = fileAccessI.write (b,0,nRead); #nX0xV5=  
} 3X*;.'#Z  
catch(Exception e){e.printStackTrace ();} r^_8y8&l  
} G{}E~jDi?  
} 9fMg?  
>},O_qx  
HnUM:-6  
//打印回应的头信息 )FT~gl%  
public void logResponseHead(HttpURLConnection con) 6g29!F`y  
{ +cheLc  
for(int i=1;;i++) qi`*4cas*A  
{ 71 hv~Nk/x  
String header=con.getHeaderFieldKey(i); ,AGK O,
w  
if(header!=null) !;pmql  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9~ajEs  
Utility.log(header+" : "+con.getHeaderField(header)); jIv+=b#oT  
else 'SYjEhvw  
break; BR
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} hz<kR@k}  
} rl'YyO}2  
;H_yNrwA  
,[,+ _A  
public void splitterStop() g~h`wv'  
{ VhT4c+Zs  
bStop = true; y^Oj4Y:  
} =bded(3Z  
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} 0@C`QW%m  
uZz^>*b  
cInzwdh7  
/*  ?Vbe  
**FileAccess.java ]d_Id]Qa+  
*//文件访问(定位，写) !lm^(SSv  
package NetFox; 7`6n]4e  
import java.io.*; OQ 5{#  
;EW]R9HCH  
@za?<G>!'e  
public class FileAccessI implements Serializable{ YgQ_P4B;  
92]>"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 {{ R/:-6?@  
RandomAccessFile oSavedFile; o(]kI?
`  
long nPos; ~/!Zh  
64#~p)  
L

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public FileAccessI() throws IOException $bF.6  
{ IxYuJpi  
this("",0); Z=z'j8z3  
} ~4=4Ks0  
Q6_!I42Y`  
HO41)m+&  
public FileAccessI(String sName,long nPos) throws IOException "@ Zy+zLU  
{ U.crRrN  
oSavedFile = new RandomAccessFile(sName,"rw"); (toGU  
this.nPos = nPos; Iu2RK  
oSavedFile.seek(nPos); $T^O38$  
} 7xVI,\qV  
Z]1~9:7ap  
Um9!<G=;  
public synchronized int write(byte[] b,int nStart,int nLen) pb{'t2kk  
{ hnvn&{|  
int n = -1; ?T$i  
try{ n~8-+$6OR  
oSavedFile.write(b,nStart,nLen); |C=^:@}ri?  
n = nLen; ORv[Gkq_N)  
} X z2IAiAs'  
catch(IOException e) 1#(,Bq4  
{ ^gw_Up<e6  
e.printStackTrace (); wI #_r_  
} 6.Ef
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L G,XhN  
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return n; >>(2ZJ  
} ^KF  
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} {Ylj]  
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(FH4\'t)  
/* L;,Nh  
**SiteInfoBean.java l"IBt:  
*/ MZn7gT0  
package NetFox; 7xwS .|
 
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]o6yU#zn~e  
public class SiteInfoBean { wjq f u /  
Q7"KgqpQ3  
2i |wQU5w  
private String sSiteURL; //Site's URL QMy;?,  
private String sFilePath; //Saved File's Path WYRTt2(+%  
private String sFileName; //Saved File's Name S'Yg!KwX  
private int nSplitter; //Count of Splited Downloading File g}ciG!0  
[53@'@26  
_#f/VE  
public SiteInfoBean() Arir=q^2  
{//nSplitter的缺省值为5 duXv [1  
//default value of nSplitter is 5 F8_pwJUpf-  
this("","","",5); B V+"uF  
} eJ'2CM6  
cX7xG U  
gWy2$)  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) C([;JO 11[  
{ $aE%W? \  
sSiteURL= sURL; F=iz\O!6  
sFilePath = sPath; *N\U{)b\  
sFileName = sName; .}SW`RPk  
this.nSplitter = nSpiltter; P8DJv-f`  
dMeDQ`
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E|6X.Ny]   
} / DeIs  
pA(@gisg  
hP3I_I[qF}  
public String getSSiteURL()
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{ g@MTKqs  
return sSiteURL; egx(N <  
} E^A9u
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wbd>By(T1  
9y.C])(2  
public void setSSiteURL(String value) .Ks&r  
{ -$dnUXFsj[  
sSiteURL = value; ?*[t'D9f-  
} 3|9)A+,#  
Uk|Xs~@#E  
%9{4g->  
public String getSFilePath() [g&Q_+,j  
{ Wj.)wr!  
return sFilePath; -a&wOn-W  
} y ?4|jN  
-Zocu<Rs  
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public void setSFilePath(String value) 'PV,c|f>  
{ 1ww|km  
sFilePath = value; Rp}6}4=d  
} @iC
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qi7dcn@d  
'e;*V$+  
public String getSFileName() Gxm+5q  
{ N7+K$)3  
return sFileName; 4?jhZLBU  
} _f^q!tP&d  
r;upJbSX  
L_)?5IOJ$  
public void setSFileName(String value) N4)&K[  
{ jqb,^T|j;m  
sFileName = value; kJJQcjAP:  
} G\jr^d\  
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;PG
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public int getNSplitter() PJO;[: .I  
{ N|1J@"H  
return nSplitter; c7wza/r>  
} u`E_Q8  
^h^j:!76j  
6K?+adKlc  
public void setNSplitter(int nCount) 5>h2WL  
{ -lb}}z+/  
nSplitter = nCount; c{||l+B  
} YwB5Zqr  
} Srol0D I  
{D`F$=Dlw  
(:-DuUt  
/* O}#*U+j  
**Utility.java 6D0uLh  
*/ RR`?o\  
package NetFox; r'xa'6&  
->8n
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#cjB <APY  
public class Utility { LoBKR c2t  
L d#  
G@,qO#5&  
public Utility() F!zZIaB]  
{ Ix1ec^?f  
Z [68ji]  
x6:$lZ(  
} (_<ruwV]`  
]Ms~;MXlx5  
//线程睡眠 3 5|5|ma  
public static void sleep(int nSecond) <`6-J `.  
{ G V0q?  
try{ m#%5H  
Thread.sleep(nSecond); =_ -@1 1a  
} :hxfd b-  
catch(Exception e) .>CqZN,^  
{ .lTGFeJqZ4  
e.printStackTrace (); hr]NW>;  
} dzbzZ@y  
} @iWIgL  
XPWK"t01  
//日志 ~^Vt)/}Q  
public static void log(String sMsg) v,p/r)E  
{ ,YH^jc  
System.err.println(sMsg); 7F+w o  
} >@ge[MuS  
yKfRwO[j  
O-  r"G  
public static void log(int sMsg) %li'j|  
{ u!{P{C  
System.err.println(sMsg); |? r,W~9`  
} ;[dcbyu@  
} V=E9*$b]  
|y;+xEl6  
eeB^c/k(P  
/* ,h>0k`J:a  
**TestMethod.java ChmPO|2F  
*/ 7i6-Hq  
package NetFox; JrCm >0g  
;QgJw2G  
gX6'!}G
8]  
public class TestMethod { _W?}%;  
,|T   
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public TestMethod() 3G5i+9Nt.L  
{ ///xx/weblogic60b2_win.exe 0v',+-  
try{ f4X?\eGT  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r 97 VX>  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }$iH3#E8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Hh54&YKZ  
fileFetch.start(); *"1]NAz+  
} Eiz\Nb  
catch(Exception e){e.printStackTrace ();} Pme`UcE3H  
1 ht4LRFi  
>JC.qjA  
} s u![ST(  
37M7bB0  
<\Y>y+$3  
public static void main(String[] args) ;:"~utL7  
{ f9OVylm  
new TestMethod(); O
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} T<p>:$vo  
} "o[\Aec:  
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