http断点续传简单实现（java)

/* ?}#Iu
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**SiteFileFetch.java sgRWjrc/  
*/ 3Hi8=*  
package NetFox; 6FY.kN\  
import java.io.*; lIPz"  
import java.net.*; \\;y W~  
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public class SiteFileFetch extends Thread { $laUkD#vz  
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SiteInfoBean siteInfoBean = null; //文件信息Bean M0$E_*  
long[] nStartPos; //开始位置 je%D&ci$  
long[] nEndPos; //结束位置 b@O{eQB  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 H4$f+  
long nFileLength; //文件长度 NryOdt tI  
boolean bFirst = true; //是否第一次取文件 jB`:(5%RO  
boolean bStop = false; //停止标志 +!ZfJZls  
File tmpFile; //文件下载的临时信息 / }*}r  
DataOutputStream output; //输出到文件的输出流 u:^sEk"Lk'  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） !t}yoN n|  
public SiteFileFetch(SiteInfoBean bean) throws IOException Z\cD98B#
 
{ ]r'D  
siteInfoBean = bean; M3r;Pdj2r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); VOIni<9y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); eD7qc1*G  
if(tmpFile.exists ()) mtdy@=?1Y  
{ rAE5.Q!u  
bFirst = false; |a%Wd  
read_nPos(); hzT)5'_  
} F|@\IVEB]  
else Tgh?=]H  
{ -hc8IS
 
nStartPos = new long[bean.getNSplitter()]; v0?SN>fZ  
nEndPos = new long[bean.getNSplitter()]; vmh>|N4a7  
} 3gnO)"$  
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} Z{gm4YV  
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public void run() I?^(j;QpS  
{ .h\Py[h<^  
//获得文件长度 |>Fz:b d  
//分割文件 V7.g,  
//实例FileSplitterFetch u:mndTpB6x  
//启动FileSplitterFetch线程 M93*"jA  
//等待子线程返回 Cc;8+Z=a?G  
try{ Sp*4Z`^je  
if(bFirst) gA
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{ .rS. >d^n  
nFileLength = getFileSize(); >|yP`m   
if(nFileLength == -1) (.X)=  
{ FBbaLqgVF{  
System.err.println("File Length is not known!"); @_7rd  
} Hp>L}5 y[  
else if(nFileLength == -2) `- (<Q;iO  
{ WIuYSt)h  
System.err.println("File is not access!"); g[bu9i  
} :Zx|=  
else `oH4"9&]k3  
{ SN]g4}K-  
for(int i=0;i<nStartPos.length;i++) Ln t 1  
{ lRNm &3:-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); iQS,@6  
} oOC&w0  
for(int i=0;i<nEndPos.length-1;i++) `( w"{8laB  
{ _ Yc"{d3S  
nEndPos = nStartPos[i+1]; 3zu6#3^  
} 5-y*]:g(  
nEndPos[nEndPos.length-1] = nFileLength; ,II3b(l  
} LrT EF j  
} /|<SD.:  
=,h'}(z_  
0{ ~2mggh  
//启动子线程 L`X5\D'X  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VBw5[  
for(int i=0;i<nStartPos.length;i++) 841y"@*BY  
{ - jCj_@n  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), e([>sAx!1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), B\e*-:pq>  
nStartPos,nEndPos,i); l#%7BGwzY  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }WaZ+Mdg\  
fileSplitterFetch.start(); "qd|!:bE  
} 9x|`XAB  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), C#^y{q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); jT}={[9b  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Y;%LwDC  
nEndPos = " + nFileLength); 8>Cf}TvErx  
// fileSplitterFetch[nPos.length-1].start(); \$*CXjh3G  
t$wbwP  
r-TrA$k  
//等待子线程结束 _U-`/r o  
//int count = 0; 9}m?E<6&  
//是否结束while循环 @!u{>!~0  
boolean breakWhile = false; +L`}(yLJ)9  
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while(!bStop) ^D
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{ Z"%.  
write_nPos(); euVDrJ^  
Utility.sleep(500); 2[HPU M2>  
breakWhile = true; GK!@|Kk8q7  
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for(int i=0;i<nStartPos.length;i++) x\(#  
{ p:5NMo  
if(!fileSplitterFetch.bDownOver) q4&! mDU  
{ A[ncwJ  
breakWhile = false; MP)Prl>  
break; kfZ`|w@q  
} u~i
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} aHmg!s}&  
if(breakWhile) $ P5K  
break;  Pd\4hy  
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//count++; Z,e|L4&  
//if(count>4) *DC/O( 0  
// siteStop(); ]& ckq  
} 8.n#@%  
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_:=\h5}8  
System.err.println("文件下载结束！"); HbI{Xf[6LP  
} 6V%}2YE?X  
catch(Exception e){e.printStackTrace ();} vt2. i$u  
} G<D8a2q  
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\<*F#3U1  
//获得文件长度 cWZITT{A  
public long getFileSize() tWTHyL  
{ 'z AvQm  
int nFileLength = -1; =eUKpYI  
try{ GdI,&|/  
URL url = new URL(siteInfoBean.getSSiteURL()); {?0'(D7.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t;6<k7h  
httpConnection.setRequestProperty("User-Agent","NetFox"); q+9->D(6  
Q=Mv"~2>B  
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int responseCode=httpConnection.getResponseCode(); ^tGAJ_b79  
if(responseCode>=400) o>C,Db~L/  
{ L6PgWc;m  
processErrorCode(responseCode); oI/_
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return -2; //-2 represent access is error ][jwy-Uy;  
} 5\C(2naf  
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String sHeader; |ymW0gh7o$  
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for(int i=1;;i++) :_6o|9J\t  
{ ,"is%O.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); k
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//Utility.log(in.readLine()); wGNEb  
sHeader=httpConnection.getHeaderFieldKey(i); :rQDA=Ps  
if(sHeader!=null) eN.6l2-  
{ XYuX+&XW/  
if(sHeader.equals("Content-Length")) *6` ^8Y\  
{ 1>rQ).eT  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); !DFTg4xb  
break; P"^Yx8L#  
} <q!HY~"V  
} j0}wv
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else R9R~$@~G  
break; mMwV5\(  
} syW[uXNLZ  
} x5uz$g  
catch(IOException e){e.printStackTrace ();} X^N6s"2  
catch(Exception e){e.printStackTrace ();} J Fn
E
{  
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Utility.log(nFileLength); >IrQhSF  
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return nFileLength; IC'+{3.m8  
} Ft11?D B  
d9:I.SA)E  
dY&v(~&;]  
//保存下载信息（文件指针位置） #~nXAs]Q  
private void write_nPos() y/Y}C.IWp)  
{ \Hrcf+`  
try{ hGY-d}npAJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /)J]ItJlz  
output.writeInt(nStartPos.length); W7WHDL^  
for(int i=0;i<nStartPos.length;i++) \99'#]\_/E  
{ ]NTQF/   
// output.writeLong(nPos); G<-KwGy,D  
output.writeLong(fileSplitterFetch.nStartPos); 4AJT)I.  
output.writeLong(fileSplitterFetch.nEndPos); %<nGm\  
} 8iaMr278W  
output.close(); &?bsBqpN  
} ~/K&=xE  
catch(IOException e){e.printStackTrace ();} NzyEsZ]$  
catch(Exception e){e.printStackTrace ();} ai$l7]7  
} pP":,8Q{  
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//读取保存的下载信息（文件指针位置） `oikSx$vB.  
private void read_nPos() =t-Ud^3  
{ !9 kNL  
try{ |OF3O,5z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #oTVfY#  
int nCount = input.readInt(); g]L8Jli  
nStartPos = new long[nCount]; ,H"}Rw
 
nEndPos = new long[nCount]; 1q!k#Cliu  
for(int i=0;i<nStartPos.length;i++) 1
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{ J' P:SC1  
nStartPos = input.readLong(); ^2$b8]q  
nEndPos = input.readLong(); YU-wE';H6  
} TxK v!-1  
input.close(); \A\  
} oCOv 6(  
catch(IOException e){e.printStackTrace ();} [>?|wQy>=  
catch(Exception e){e.printStackTrace ();} h SS9mQ  
} =<HekiYM  
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private void processErrorCode(int nErrorCode) )J@[8 x`  
{ J[?oV;O  
System.err.println("Error Code : " + nErrorCode); jRC{8^
98  
} \Qah*1  
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//停止文件下载 *(yw6(9%  
public void siteStop() c{1)-&W  
{ A}9^,C$#  
bStop = true; 3l~7  
for(int i=0;i<nStartPos.length;i++) 1YMi4.  
fileSplitterFetch.splitterStop(); =p[Sd*d  
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} b*h:e.q  
} o'$-  
//负责部分文件的抓取 .jP|b~  
**FileSplitterFetch.java P??P"^hU  
*/ Vbp
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package NetFox; .$cX:"_Mk  
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import java.io.*; 2 oL$I(83  
import java.net.*; C<a&]dN/  
&?QKWxN  
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public class FileSplitterFetch extends Thread { Gq1C"s$4'  
<ndY6n3  
J)Yz@0#T(;  
String sURL; //File URL uaP5(hUI  
long nStartPos; //File Snippet Start Position nX7F<k4G2  
long nEndPos; //File Snippet End Position -2}ons(  
int nThreadID; //Thread's ID y{(Dv} 
 
boolean bDownOver = false; //Downing is over j07A>G-=  
boolean bStop = false; //Stop identical Cd^1E]O0{  
FileAccessI fileAccessI = null; //File Access interface !U4YA1>>  
g/$RuT2U  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \bF<f02P  
{ R$u1\r1I  
this.sURL = sURL; F7C+uGTs  
this.nStartPos = nStart; 4Hf'/%kW  
this.nEndPos = nEnd; XLiwE$:t%  
nThreadID = id; ~5|R`%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 fGeie m  
} s~(`~Y4  
)Az0.}  
b(@GKH"W  
public void run() ^"lEa-g&  
{ Xl<*Fn?  
while(nStartPos < nEndPos && !bStop) GBS+ 4xL|  
{ 7R5ebMW V  
*\:sHVyG(  
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try{ `j
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URL url = new URL(sURL); |AExaO"jk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k fY;  
httpConnection.setRequestProperty("User-Agent","NetFox"); Xajt][  
String sProperty = "bytes="+nStartPos+"-"; |ul{d|  
httpConnection.setRequestProperty("RANGE",sProperty); % mPv1$FH  
Utility.log(sProperty); 'e<8j  
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InputStream input = httpConnection.getInputStream(); AwuhFPG  
//logResponseHead(httpConnection); w#BT/6
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2H8\P+  
byte[] b = new byte[1024]; -0`
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int nRead; er BerbEEH  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Yevd h<  
{ 8.wtv5eZ  
nStartPos += fileAccessI.write(b,0,nRead); 4!ZT_q  
//if(nThreadID == 1) >@G"*le*)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y~OP9T
g  
} mIrN~)C4\  
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>U\P^y
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Utility.log("Thread " + nThreadID + " is over!"); 1\lZ&KX$i  
bDownOver = true; <i
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//nPos = fileAccessI.write (b,0,nRead); By[M|4a  
} 5(1c?biP&  
catch(Exception e){e.printStackTrace ();} :>ca).cjac  
} ^u90N>Dvq  
} q3v5gz^t  
ntPX?/  
N2j^fZd_  
//打印回应的头信息 WCqa[=v)t  
public void logResponseHead(HttpURLConnection con) _ A{F2M  
{ !%(kMN  
for(int i=1;;i++) W%&s$b(  
{ ?%ltoezf  
String header=con.getHeaderFieldKey(i); -+2A@kmEJ  
if(header!=null) 4%<wxrod  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); G[`2Nd<  
Utility.log(header+" : "+con.getHeaderField(header)); PD^ 6Ywn>s  
else /={N^8^=x  
break; u^'X>n)oL#  
} +o,f:Ih  
} icVB?M,m  
;U a48pSv  
q!><:"#[G  
public void splitterStop() :YX5%6  
{ [\fwn
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bStop = true; e`JWY9%  
} 2*gB~Jn4  
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} x{G 'IEf  
f4 +P2j  
XXwo(trs~=  
/* g&.OJ  
**FileAccess.java NTCFmdbs 6  
*//文件访问(定位，写) ZcHIk{|  
package NetFox; [T[]U  
import java.io.*; 5V/]7>b1  
,|#biT-<T  
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public class FileAccessI implements Serializable{ $Dv5TUKw  
9`H4"H>yG  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 tblduiN   
RandomAccessFile oSavedFile; # eFdu  
long nPos; f\RTO63|O  
_T805<aUW\  
%'X7T^uE  
public FileAccessI() throws IOException k7sD"xR3  
{ dxS5-aWy9w  
this("",0); Cd6t
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} 33~8@]b  
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public FileAccessI(String sName,long nPos) throws IOException 5vS[{;<&  
{ tU!Yg"4Q  
oSavedFile = new RandomAccessFile(sName,"rw"); f
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this.nPos = nPos; Zrgv*  
oSavedFile.seek(nPos); UbIUc}ge  
} =jxy4`oF  
"|,KXv')  
~GJ;;v1b2  
public synchronized int write(byte[] b,int nStart,int nLen) /Q89y[  
{ QTN24 q4  
int n = -1; #_IuB) qy  
try{ {+Wknm%  
oSavedFile.write(b,nStart,nLen); oxI?7dy5  
n = nLen; 7GErh,  
} Q$k#q<+0  
catch(IOException e) B o%Sl  
{ SY@;u<Pd  
e.printStackTrace (); jlqSw4_  
} MIiBNNURX  
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return n; 7@k3-?q  
} G-:7,9  
7>0/$i#'Vl  
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} ]!jfrj  
 #3RElI  
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/* v:w^$]4  
**SiteInfoBean.java
NMC0y|G  
*/ V_ntS&2o  
package NetFox; =@h
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Nm-E4N#'i  
0;OZ|;Z  
public class SiteInfoBean {
~Dw% d;  
n\BV*AH  
*/@I$*  
private String sSiteURL; //Site's URL XJwgh y?(  
private String sFilePath; //Saved File's Path 4L97UhLL  
private String sFileName; //Saved File's Name F~OQ'59!Pf  
private int nSplitter; //Count of Splited Downloading File @`^Z5n.4  
*mYGs )|  
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public SiteInfoBean() F|oyrG  
{//nSplitter的缺省值为5 ,K30.E  
//default value of nSplitter is 5 OJM2t`}_t  
this("","","",5); 9q[[ ,R  
} B|M@o^Tf  
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[T/S/@IT  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $ )2zz>4  
{ SD@ 0X[  
sSiteURL= sURL; ?=-/5A4K  
sFilePath = sPath; b+
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sFileName = sName; W?ghG  
this.nSplitter = nSpiltter; MhD=\Lpj\  
a^[s[j#^,  
j>.1RG  
} }6{00er  
~xws5n}F  
1L?W+zMO  
public String getSSiteURL() P"@^BQ4  
{ K_.|FEV  
return sSiteURL; N_+D#Z.g  
} WZTv  
\-[ >bsg  
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public void setSSiteURL(String value) =n@\m<  
{ i2[8^o`_  
sSiteURL = value; x~D8XN{  
} 2jkma :$'  
R4DfqX  
zQu
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public String getSFilePath() txX>zR*)  
{ ?UeV5<TewS  
return sFilePath; aJ1{9 5ea  
} Kf,AnKkn'  
A ;|P
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public void setSFilePath(String value) @2_E9{T  
{ y T&#k1  
sFilePath = value; :TV`uUE  
} T+%P+  
~9;udBfwF  
) <w`:wD  
public String getSFileName() #nZPnc:  
{ ^L.'At  
return sFileName; $ma@z0%8}  
} p^ OHLT  
3m$Qd#|  
]-;JHB5A_:  
public void setSFileName(String value) @,W5K$Ka=  
{ t/3qD7L  
sFileName = value; _[wG-W/9R  
} ^B7Ls{  
l%2 gM7WMY  
>m%7dU  
public int getNSplitter() lB#7j  
{ ^E+fmY2a  
return nSplitter; Np$ue }yr  
} {qCFd  
E!L_"GW  
}-9 c1&m  
public void setNSplitter(int nCount) O+[s4]  
{ ~K(mt0T)  
nSplitter = nCount; )YwLj&e4tf  
} .%M8
0X{5~  
} Re*~C:  
WQBV~.<Yv  
2dbn~j0  
/* q:vGGK^  
**Utility.java |nqN95'u+]  
*/ =gZA9@]W2  
package NetFox; _({wJ$aYC  
7>AMzNj  
u?'J1\z  
public class Utility { j}fSz)`i  
kD)]\  
l?Ls=J*  
public Utility() J?hs\nA  
{ gebL6oc%  
ni<\AF]`  
:H:+XIgoR  
} }2Y`Lr  
3|EAOoWnK  
//线程睡眠 4C*0MV  
public static void sleep(int nSecond) 2NB$(4/  
{ z2#k/3%o=  
try{ 53^3..E|  
Thread.sleep(nSecond); I\IDt~  
} >Qg-dJt[  
catch(Exception e) mSO7r F  
{ 1hc`s+N  
e.printStackTrace (); OXB 5W#$  
} E[BM0.#bZ  
} oE0~F|(\1  
S5YEz XG  
//日志 7=&+0@R#/d  
public static void log(String sMsg) E*s _Y  
{ =T)y(] ;M$  
System.err.println(sMsg); ]]y,FQ,r  
} 9`KFJx6D  
$-s8tc(  
}U%T6~_wR  
public static void log(int sMsg) O:imX>|u  
{ ]!s@FKC{;  
System.err.println(sMsg); /fU-0a8  
} RS@G.|  
} aadw#90  
uh>"TeOi  
[<d_#(]h'  
/* Y3-f68*(  
**TestMethod.java X0]$Ovq(l  
*/ }VHvC"  
package NetFox; KUUZN  
bkrl>Im<n  
(CAkzgTfc  
public class TestMethod { /-(OJN5F^  
C 7YS>?^]  
vJsg6oH  
public TestMethod() H.o3d/8:  
{ ///xx/weblogic60b2_win.exe IIF <Zkpb  
try{ ='-/JH~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -<e_^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Jid_&\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +"|TPKas  
fileFetch.start(); "{c@}~  
} &!FI!T -WH  
catch(Exception e){e.printStackTrace ();} Gh<#wa['}  
fwa*|y;  
@4Q/J$  
} GgE 38~A4  
=)x+f/c]  
:'[ha$  
public static void main(String[] args) ?u0qYep:  
{ ]O0u.=1k  
new TestMethod(); Cm0K-~ U  
} 6y"T;.FAo  
} o WAy[  
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