http断点续传简单实现（java)

/* 9>4#I3  
**SiteFileFetch.java i975)_X(  
*/ &j:e<{@  
package NetFox; zd5=W"Y;]  
import java.io.*; i!2k f  
import java.net.*; +\Vw:
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1|{s8[;8  
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public class SiteFileFetch extends Thread { b[:,p?:@  
4tm%F\Izy  
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SiteInfoBean siteInfoBean = null; //文件信息Bean _]5UuIMl  
long[] nStartPos; //开始位置 )f$4:Pq  
long[] nEndPos; //结束位置 /!
0&b?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 i@+m<YS:2>  
long nFileLength; //文件长度 @ovaOX  
boolean bFirst = true; //是否第一次取文件 ,+df=>$W  
boolean bStop = false; //停止标志 9xbT?$^  
File tmpFile; //文件下载的临时信息 n>pJ/l%`  
DataOutputStream output; //输出到文件的输出流 QD0x^v8  
{v
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） /%;J1{O  
public SiteFileFetch(SiteInfoBean bean) throws IOException G%HG6  
{ B{=DnB6  
siteInfoBean = bean; *jhgCm  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));  jfK&CA  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~E6sY  
if(tmpFile.exists ()) rSv,;v  
{ )&T 5/+  
bFirst = false; 4AEw[(t  
read_nPos(); |kh{EUE ;  
} JYWoQ[ZO#>  
else T/ECW  
{ 9]+zZP_#  
nStartPos = new long[bean.getNSplitter()]; }IWt\a<d  
nEndPos = new long[bean.getNSplitter()]; BEvt{q4  
} Zq
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[_%u5sc-y  
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564L.^$@|  
} Jvc<j:{^w  
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+pgHCzwJE  
public void run() uxn+.fA  
{ 6IRRRtO(  
//获得文件长度 =c\(]xX  
//分割文件 A-1KTD  
//实例FileSplitterFetch MOh&1]2j5  
//启动FileSplitterFetch线程 {HY3E}YJL  
//等待子线程返回 >{{ds--  
try{ muXP5MO  
if(bFirst) 7WH'GoBh  
{ d#+Nef5  
nFileLength = getFileSize(); dH5*%  
if(nFileLength == -1) 5uG^`H@X  
{ _R(ZvsOZ  
System.err.println("File Length is not known!"); ]#4kqj}  
} <w}^Z}fpk&  
else if(nFileLength == -2) kjPf%*3  
{ ?i_
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System.err.println("File is not access!"); +a*Ic8*  
} JAKs [@:  
else d)U(XiK'  
{ HD#>K 7  
for(int i=0;i<nStartPos.length;i++)
>n/0od9  
{ jNx{*2._r  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @ NDcO,]  
} qbSI98rw  
for(int i=0;i<nEndPos.length-1;i++) e8f7*S8  
{ ;;i419  
nEndPos = nStartPos[i+1]; 075IW"p'  
} &a'mG=(K_c  
nEndPos[nEndPos.length-1] = nFileLength; lIEZ=CEmY  
} 8J&9}@y  
} ~pp< T  
du}HTrsC  
~M* UMF^  
//启动子线程 h{o,
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; L"vk ^>E6  
for(int i=0;i<nStartPos.length;i++) kuBtPZ  
{ !nL94:8U  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :RIqA/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :j3^p8]  
nStartPos,nEndPos,i); |FT.x9e-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cM9>V2:P  
fileSplitterFetch.start(); ]U~{?K'g@j  
} VJ'-"8tY&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6(?@B^S>2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); n%\\1  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", + AjV0#n  
nEndPos = " + nFileLength); ik?IC$*n3i  
// fileSplitterFetch[nPos.length-1].start(); dk1q9Tx  
]3|h6KWq  
[7x;H  
//等待子线程结束 ?$;&DoE  
//int count = 0; V6ECL6n  
//是否结束while循环 &<#1G u_  
boolean breakWhile = false; w=-{njMz6&  

\Qv:7;?  
0)PZS>  
while(!bStop) $B>L_~cS  
{ GM;uwL#  
write_nPos(); l0yflF
Gr  
Utility.sleep(500); ~ cu+QR)  
breakWhile = true; bZK`]L[   
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 `m_fi  
for(int i=0;i<nStartPos.length;i++) Z$Ps_Ik  
{ n|=yw6aV'  
if(!fileSplitterFetch.bDownOver) {hO|{vz  
{ ?JRfhJ:j  
breakWhile = false; 26_PFHQu4  
break; {Xpjm6a7  
} R. ryy  
} 2"xhFxoD7  
if(breakWhile) Z^A(Q>{e  
break; |`wJ {-  
?~}8^~3  
-xH3}K%  
//count++;  q_;#EV  
//if(count>4) z}VCiS0  
// siteStop(); bw#\"uJ  
} 2j>C4Ck  
uWXxK"J.  
pek5P4W_  
System.err.println("文件下载结束！"); eBECY(QMQ  
} 1*@Q~f:Uk  
catch(Exception e){e.printStackTrace ();} b$Bq#vdg:  
} 5=MM^$QG  
6l>016 x  
#zd}xla0]  
//获得文件长度 Tkf4`Gxd  
public long getFileSize() ON_GD"  
{ 7.^1I7O  
int nFileLength = -1; /8(t:  
try{ oB}rd9  
URL url = new URL(siteInfoBean.getSSiteURL()); LrV4^{9(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )i.\q  
httpConnection.setRequestProperty("User-Agent","NetFox"); ORV'dr  
N;,N6&veK/  
3o__tU)B  
int responseCode=httpConnection.getResponseCode(); 2-wvL&pi)  
if(responseCode>=400) !.={p8X-x  
{ na4^RPtN\e  
processErrorCode(responseCode); %eqL)pC]  
return -2; //-2 represent access is error OEN'c0;5  
} p7
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n)teX.ck)  
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String sHeader; VrRBwvp-K  

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for(int i=1;;i++) gI~jf- w  
{ +4p gPv  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Os7 3u#!'  
//Utility.log(in.readLine()); HV6'0_R0  
sHeader=httpConnection.getHeaderFieldKey(i); thSo,uGlW  
if(sHeader!=null) =}AwA5G  
{ ep"54o5=d  
if(sHeader.equals("Content-Length")) ?_c*(2i&^  
{ 7^:0?Q  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); PizPsJ|&  
break; w,FOq?j^k  
} r5?qz<WW~  
} %sLij*  
else ~\m|pxcj  
break; FLekyJmw~  
} wMB<^zZmv  
} f)+fdc  
catch(IOException e){e.printStackTrace ();} =w!14@W  
catch(Exception e){e.printStackTrace ();} .<`Rq'  
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3E361?ubM  
Utility.log(nFileLength); "8"7AoE  
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uNYHEs6%T$  
return nFileLength; AcYL3  
} @GGPw9a  
r`L$[C5I  
RSY{I
Y  
//保存下载信息（文件指针位置） `_'I 9,.a  
private void write_nPos() *5#Y[c  
{ q<b;xx  
try{  3y?ig2  
output = new DataOutputStream(new FileOutputStream(tmpFile)); f&Bu_r  
output.writeInt(nStartPos.length); F3b[L^Km]  
for(int i=0;i<nStartPos.length;i++) PU^Z7T);  
{ *r+i=i8{  
// output.writeLong(nPos); xXu/CGzG  
output.writeLong(fileSplitterFetch.nStartPos); '@iS5Fni  
output.writeLong(fileSplitterFetch.nEndPos); $vdGkz@6  
} #IP<4"Hf  
output.close(); 16YJQ ue  
} )A['+s  
catch(IOException e){e.printStackTrace ();} 3D k W  
catch(Exception e){e.printStackTrace ();} cV5Lp4wY?  
} AtA}OY]D/  
?/~7\ '|Z  
}9Z?UtS  
//读取保存的下载信息（文件指针位置） 928szUo:  
private void read_nPos() b#.hw2?a`  
{ 8KW}XG  
try{ 8lt P)K4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); kO\(6f2|x  
int nCount = input.readInt(); y2^r.6"O  
nStartPos = new long[nCount]; Fp06a!7<  
nEndPos = new long[nCount]; Ne.W-,X^cL  
for(int i=0;i<nStartPos.length;i++) #T n~hnW  
{ c% 0h!zF  
nStartPos = input.readLong(); rBkf@  
nEndPos = input.readLong(); WFg'G>*  
} Hi9;i/  
input.close(); j+J)S1  
} O.1Z3~r-N  
catch(IOException e){e.printStackTrace ();} X1i6CEa<  
catch(Exception e){e.printStackTrace ();} v/Z}|dT"  
} *#frbV?;  
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private void processErrorCode(int nErrorCode) :j vx-jQ  
{ lbgnO s,  
System.err.println("Error Code : " + nErrorCode); yGH'|`  
} l0u6nGkh  
n\.K:t[:  
<0R7uH  
//停止文件下载 M{:gc7%  
public void siteStop() OsAXHjX}  
{ EUe2<G  
bStop = true; !Il>,q&F  
for(int i=0;i<nStartPos.length;i++) hX 9.%-@sR  
fileSplitterFetch.splitterStop(); 1p23&\\~  
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@|%t<{y^I  
} \%EZg  
} o]}b#U8S  
//负责部分文件的抓取 4G@vO{$  
**FileSplitterFetch.java %7O`]ik:  
*/ =1^Ru*G  
package NetFox; -t?S:9[w  
p2!x8`IB*  
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import java.io.*; /+sn-$/"i  
import java.net.*; <jw`"L[D
 
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public class FileSplitterFetch extends Thread { 9 o-T#~i  
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Uv[:Aj  
String sURL; //File URL E`XUK,b  
long nStartPos; //File Snippet Start Position A]BG*  
long nEndPos; //File Snippet End Position vV#Jl)
A  
int nThreadID; //Thread's ID idPkJf/  
boolean bDownOver = false; //Downing is over =35EG{W(  
boolean bStop = false; //Stop identical QCa$<~c  
FileAccessI fileAccessI = null; //File Access interface N^
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)`-9WCd&  
KTBsH;6  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException *ta|,  
{ (LTm!"Q  
this.sURL = sURL; 6rt.ec(  
this.nStartPos = nStart; bW3e*O$V  
this.nEndPos = nEnd; HHWB_QaL  
nThreadID = id; x~j
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 wRnt$1  
} 8T
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_ 97F  
public void run() Z\(+a
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{ Q++lgVh)E  
while(nStartPos < nEndPos && !bStop) jp=^$rS6[  
{ h+,zfVJu  
rbO9NRg>  
]#j]yGV  
try{ tE3!;  
URL url = new URL(sURL); s7(mNpo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); NLoJmOi;L7  
httpConnection.setRequestProperty("User-Agent","NetFox"); ="d}:Jl  
String sProperty = "bytes="+nStartPos+"-"; _;v4]MU  
httpConnection.setRequestProperty("RANGE",sProperty); L:XnW1(Or  
Utility.log(sProperty); ,D+pGxbr   
|M)'@s:  
(t>BO`,  
InputStream input = httpConnection.getInputStream(); +QtK "5M  
//logResponseHead(httpConnection); \uQ(-ji  
9{'GrL  
,Tvk&<!0  
byte[] b = new byte[1024]; vtCt6M  
int nRead; TW{.qed8^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) flVQG@  
{ ]6GdB3?UVM  
nStartPos += fileAccessI.write(b,0,nRead); (05/}PhB`  
//if(nThreadID == 1) 8}XtVF;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); QyJ}zwD  
} ^UEI`_HO0  
^0pd- n@pn  
-3_-n*k!  
Utility.log("Thread " + nThreadID + " is over!"); QPg QM6  
bDownOver = true; ,gUSW  
//nPos = fileAccessI.write (b,0,nRead); 4~P{H/]  
} [_G_Wl'#8  
catch(Exception e){e.printStackTrace ();} brl(7_2  
} Xg^`fRg =T  
} ]p\7
s  
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3yszfWr  
//打印回应的头信息 *l)_&p  
public void logResponseHead(HttpURLConnection con) WJ<nc+/
v:  
{ _<6
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for(int i=1;;i++) |cEJRs@B  
{ n!2"pRIi  
String header=con.getHeaderFieldKey(i); s{(aW5$!s  
if(header!=null) V:fz  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Aq yR+  
Utility.log(header+" : "+con.getHeaderField(header)); A5S9F8Q/]  
else $]2srRA^A  
break; :1^ R$0d  
} LBq~?Q.e  
} 4w
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v8Vw.Ce`f  
!_ZknZTT  
public void splitterStop() cfBq/2I  
{ |`+kZ-M*  
bStop = true; m2F2  
} {;4Y5kj  
[fx1H~T<  
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} 4wjy)VD_  
5\gL+qM0  
R4"*<%1  
/* Xb?:dlu3  
**FileAccess.java {; #u~e(W  
*//文件访问(定位，写) $\M<
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package NetFox; qB6@OS  
import java.io.*; }(k#,&Fv`  
Yv<'QC  
3*)<Y}Tc  
public class FileAccessI implements Serializable{ *j5>2-C &  
,5!&}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 p4mi\~Q  
RandomAccessFile oSavedFile; uu ahR  
long nPos; Ne<={u%  
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public FileAccessI() throws IOException p7et>;WRx  
{ G"k.sRKu  
this("",0); 8Na.H::cZ  
} V`P8oIOh]  
^*sDJ #  
YnM&t ;TX  
public FileAccessI(String sName,long nPos) throws IOException X$*MxMNs  
{ {1?94rz  
oSavedFile = new RandomAccessFile(sName,"rw"); UWU(6J|Fk  
this.nPos = nPos; d*qb^C{'"  
oSavedFile.seek(nPos); R[_Q}W'HG  
} C,;T/9  
k;5$]^x  
ga?:k,xv  
public synchronized int write(byte[] b,int nStart,int nLen) $Lj~ge3#  
{ 6HroKu  
int n = -1; rA+UftC:p6  
try{ 1Vf?Rw  
oSavedFile.write(b,nStart,nLen); V52>K$j  
n = nLen; q+iG:B/Z  
} JJ:pA_uX  
catch(IOException e) -VZn`6%s  
{ Zv]'9,cbk  
e.printStackTrace (); 1`hmD1d  
} J`6
IH#54  
* 'eE[/K  
6ZO6O=KD  
return n; 6a*?m{  
} rn$G.SMgz  
G2$<Q+UYs?  
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} #B!|sXC  
l4s*+H$vd?  
SFu]*II;
{  
/* Vu`5/QDq  
**SiteInfoBean.java ?^whK<"]  
*/ (]E0fjk  
package NetFox; H(hE;|q/  
-Oi8]Xw^@y  
~dO+kD  
public class SiteInfoBean { `uKsFXM  
XE
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0OXl`V`w  
private String sSiteURL; //Site's URL 57fl<IM  
private String sFilePath; //Saved File's Path p4F%FS:`  
private String sFileName; //Saved File's Name tk)JE^'  
private int nSplitter; //Count of Splited Downloading File l k sNy  
}qw->+nD  
E^
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public SiteInfoBean() 2tb+3K1  
{//nSplitter的缺省值为5 o)bKs>` U  
//default value of nSplitter is 5 yV~TfTJ  
this("","","",5); cP",szcY  
} upLjkQ)_  
BTzBT%mP  
*@{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) NXk~o!D  
{ {Rdh4ZKh  
sSiteURL= sURL; fN1b+d~*6  
sFilePath = sPath; 1CO
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sFileName = sName; y|0!sNg  
this.nSplitter = nSpiltter;
=H`yz

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abAw#XQ8  
eslv
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} r$1b=m,0d  
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public String getSSiteURL() [_KV;qS%/  
{ S0Ur{!9\#^  
return sSiteURL; +1a3^A\  
} `g_r<EY8/  
*8J0yv  
(j~T7og  
public void setSSiteURL(String value) FWB *=.A9  
{ k*u6'IKi.4  
sSiteURL = value; [7Q%c!e$*  
} jJaMkF;f  
#K`0b$
  
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public String getSFilePath() kS35X)-  
{ t 9t '9  
return sFilePath; bEB2q\|Je  
} J0 dY%pH#  
}VRl L>HAC  
|VzXcV-"8)  
public void setSFilePath(String value) z`YC3_d  
{ Yo1]HG(kXB  
sFilePath = value; A|,qjiEJCc  
} Fg 8lX9L  
)Fp$ *]|  
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public String getSFileName() /\_n5XI1  
{ BG8/  
return sFileName; :\I*_00!  
} eX>*}pI  
zRa2iCi  
.P`QCH;Ih  
public void setSFileName(String value) >_xuXEslUz  
{ 8MI8~
 
sFileName = value; )#8g<]q  
} P;@j  
?;_>BX|Zjl  
$qr6LIKGw  
public int getNSplitter() Ssuz
%*  
{ j#2E
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return nSplitter; t1U+7nM  
} _~MX~M3MB  
83I 5n&)  
dCS f$5  
public void setNSplitter(int nCount) ez!W0  
{ VH~YwO!x  
nSplitter = nCount; tk*-Cx?_  
} {l5fKVb\C  
} r#2Fk&Z9  
xpO;V}M|  
0}qlZFB  
/* In?#?:Q@&  
**Utility.java b=1E
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*/ ^9Cu?!xu0  
package NetFox; ,c^nW  
wBwTJCX  
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public class Utility { &Jb\}c}  
qbeUc5`1  
K)wWqC.  
public Utility() 8{/.1:  
{ ~gW^9nWYU  
t"YsIOT:O"  
A]5];c  
} MjQju@  
xlJWCA*>  
//线程睡眠 ;s{'cN[.  
public static void sleep(int nSecond) prN+{N8YC  
{ )MK$E,W  
try{ DE/SIy?  
Thread.sleep(nSecond); z8awND  
} [SC6{|  
catch(Exception e) ^7gKs2M  
{ ?.%dQ0  
e.printStackTrace (); eBnx$  
} &=jPt%7#M  
} ^ex\S8j  
1J/'R37lP  
//日志 Z;81"
  
public static void log(String sMsg)
?@,EGY<  
{ Vez8~r3  
System.err.println(sMsg); WIf.;B)L  
} -wiQd@X  
"%Y=+  
o4WQA"VxM  
public static void log(int sMsg) jL^@;"/XhC  
{ 5kTs7zJ^  
System.err.println(sMsg); ;Go^)bN ;  
} G@`F{l  
} HS{Vohy>  
M
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rN}
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/* 2wY|E<E  
**TestMethod.java MVzuE}  
*/ 196a~xNV  
package NetFox; MmjZq  
dz([GP'-*  
H)D|lt5xy  
public class TestMethod { "UMaZgI  
:IS?si5|  
f_S$CFa@  
public TestMethod() 6[A\cs  
{ ///xx/weblogic60b2_win.exe b`#YJpA  
try{ W34xrm  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .<`)`:n+B  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); B-C$>H^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); K/ On|C  
fileFetch.start(); KM?4J6jH  
} ?/3wO/
7[  
catch(Exception e){e.printStackTrace ();} CXuD%H]tx  
bzNnEH`^]  
"?3=FB
p&  
} Z?'CS|ud  
CwX?%$S   
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public static void main(String[] args) 0#J~@1Gf  
{ kzRvLs4xM  
new TestMethod(); _Rii19k  
} PF`uwx@zH  
} c6xr[tc%  
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