http断点续传简单实现（java)

/* rIWN!@.J  
**SiteFileFetch.java ;7`um  
*/ [qD<U%Hi  
package NetFox; FQ~ead36C  
import java.io.*; iN/!k.ybW}  
import java.net.*; [BR}4(7  
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f, j(uP  
public class SiteFileFetch extends Thread { u-M$45vct  
)E~\H+FP6  
;3?J#e6;  
SiteInfoBean siteInfoBean = null; //文件信息Bean "JLhOTPaHf  
long[] nStartPos; //开始位置 |VR5Q(d  
long[] nEndPos; //结束位置 5<BV\'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 E4aCGg  
long nFileLength; //文件长度 'W2$wN+P  
boolean bFirst = true; //是否第一次取文件 TNT"2FoBd  
boolean bStop = false; //停止标志 GKx,6E#JM  
File tmpFile; //文件下载的临时信息 @P5@&G  
DataOutputStream output; //输出到文件的输出流 VJtTbt;>  
<9.7gwzE  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） +:Q/<^Z  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1;~1U9V  
{ M j%|'dZz  
siteInfoBean = bean; 1z@# 8_@  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); U1!2nJ]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 78inh
%  
if(tmpFile.exists ()) QRh4f\fY  
{ nMdN$E  
bFirst = false; ^5 =E`q".  
read_nPos(); Qufv@.'AY  
} Y{|~A  
else -j=&J8Za  
{ $`dNl#G,  
nStartPos = new long[bean.getNSplitter()]; BRzWZq%r3  
nEndPos = new long[bean.getNSplitter()]; ggsi`Z{j?  
} rxI&;F#  
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s=Q*|  
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} B|$13dHfa  
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public void run() XoiYtx53  
{ /F}\V ^  
//获得文件长度 ?CZD^>6  
//分割文件 8]MzOGB8  
//实例FileSplitterFetch NITx;iC  
//启动FileSplitterFetch线程 z'D{:q  
//等待子线程返回 q]%bd[zkz  
try{ Fsj&/: q  
if(bFirst) vA-p}]%  
{ .%b_3s".  
nFileLength = getFileSize(); ^JVP2L>o*  
if(nFileLength == -1) Vd>.fb\U2  
{ s@[t5R  
System.err.println("File Length is not known!"); U7%pOpO!  
} 4S EC4yO  
else if(nFileLength == -2) GaqG8%.  
{ v]SE?xF{U  
System.err.println("File is not access!"); :;Rt#!  
} FY}*Z=D%  
else yB{o_1tc  
{ tskODM0Zf  
for(int i=0;i<nStartPos.length;i++) 2
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{ VEKITBs  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :k/U7 2  
} "g1;TT:1~  
for(int i=0;i<nEndPos.length-1;i++)  CF92AY
 
{ ^&/&I9z  
nEndPos = nStartPos[i+1]; .eXA.9|jm  
} 'J0s%m|j  
nEndPos[nEndPos.length-1] = nFileLength; hg=G//
 
} 0F'UFn>{  
} =usDI<3r  
_`
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#$B,8LFz,$  
//启动子线程 yzR=:0J  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; U`_vF~el~  
for(int i=0;i<nStartPos.length;i++) )&!@O$RS8(  
{ E!l1a5qB  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5GL+j%7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), G-?9;w'@  
nStartPos,nEndPos,i); b<78K5'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gO!h<1!  
fileSplitterFetch.start(); je3n'^m  
} <7] Y\{+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ioCkPj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); R+hS;F nh%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", q$'&RG  
nEndPos = " + nFileLength); oxXW`C<  
// fileSplitterFetch[nPos.length-1].start(); 0BE^
qe  
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Y[?Wt/O;  
//等待子线程结束 z9O/MHT[w  
//int count = 0; |Z|xM  
//是否结束while循环 8%f! X51  
boolean breakWhile = false; U(LR('-h  
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=e{KtX.  
while(!bStop) &'\+Z  
{ gt(nZ
  
write_nPos(); A8(PI)Ic.  
Utility.sleep(500); qk1D#1vl  
breakWhile = true; 6mpUk.M"  
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for(int i=0;i<nStartPos.length;i++) yP]W\W'  
{ R3`W#`  
if(!fileSplitterFetch.bDownOver) x#mk[SV  
{ IjAity.Xrq  
breakWhile = false; zNJyF;3  
break; ulo7d1OVkJ  
} =PM
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} l%~zj,ew  
if(breakWhile) _'p;V[(+M  
break; !$#4D&T  
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JjML!;  
//count++; 3h4"Rv=,  
//if(count>4) )!-'SH  
// siteStop(); o}Np}PE6  
} FWTl:LqFO  
.tsB$,/  
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System.err.println("文件下载结束！"); RUh{^3;~  
} y36aoKH  
catch(Exception e){e.printStackTrace ();} \>7-<7+I6  
} q0Pu6"^  
(OJ9@_fgG[  
V@-GQP1  
//获得文件长度 :''0z  
public long getFileSize() KL~sEli  
{ P~Owvs/=  
int nFileLength = -1; kcUt!PL  
try{ Te#[+B?  
URL url = new URL(siteInfoBean.getSSiteURL()); _>64XUZ<n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q3Lqj2r  
httpConnection.setRequestProperty("User-Agent","NetFox"); XX6)(  
5]%kWV>  
%&(\dt&R1h  
int responseCode=httpConnection.getResponseCode(); 0M-AIQ5  
if(responseCode>=400) kA`qExw%  
{ J<@]7)|U  
processErrorCode(responseCode); -v@^6bQVp  
return -2; //-2 represent access is error - [j0B|cwG  
} {v(|_j&:o  
kICYPy  
S3cQC`^  
String sHeader; ~zRd||qv  
I =pdjD  
8!Kfe  
for(int i=1;;i++) N6'Y N10  
{ uGWk(qn  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =&GV\ju  
//Utility.log(in.readLine()); i+3b)xtW7  
sHeader=httpConnection.getHeaderFieldKey(i); 3I(H.u  
if(sHeader!=null)  sOmYQ{R  
{ xw Qkk  
if(sHeader.equals("Content-Length")) ~'iuh>O)  
{ 0AenDm@9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); XWV~6"  
break; &LYZQ?|  
} VEm[F/'  
} PeaD]  
else ~<LI p%5(  
break; b\mN^P~>A  
} |lY8u~%  
} -tZb\4kh  
catch(IOException e){e.printStackTrace ();} K)ib{V(50  
catch(Exception e){e.printStackTrace ();} k2;yl_7  
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Utility.log(nFileLength); <o}t-Bgg  
*L_wRhhk  
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return nFileLength; '/?&Gol-  
} u"ow?[E  
3kg+*]tLx  
Uz_{jAhW]  
//保存下载信息（文件指针位置） L^}kwu#  
private void write_nPos() QKxuvW  
{ #a|5A:g%  
try{ ~8K~@e$./  
output = new DataOutputStream(new FileOutputStream(tmpFile)); cvt
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output.writeInt(nStartPos.length); _G`aI*rKsy  
for(int i=0;i<nStartPos.length;i++) (?(ahtT4T  
{ UQy+&;#5  
// output.writeLong(nPos); `SWK(='  
output.writeLong(fileSplitterFetch.nStartPos); w
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output.writeLong(fileSplitterFetch.nEndPos); -v] 0@jNe  
} K\PS
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output.close(); V-57BKeDz  
} ( ;q$cKy  
catch(IOException e){e.printStackTrace ();} Ff30%  
catch(Exception e){e.printStackTrace ();} IU/*YI%W  
} NDi@x"];  
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//读取保存的下载信息（文件指针位置） Sw~<W%! ?  
private void read_nPos() h 9/68Gc?6  
{ )erPp@  
try{ DpAuI w7|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 5k@k  
int nCount = input.readInt(); }T6jQ:?@  
nStartPos = new long[nCount]; .KV?;{~q@  
nEndPos = new long[nCount]; mz''-1YY$  
for(int i=0;i<nStartPos.length;i++) [z?XVl<  
{ 4Q.70  
nStartPos = input.readLong(); O<5bsKw'r  
nEndPos = input.readLong(); Cv3H%g+as  
} SU^/qF%8  
input.close(); &E~7ty'  
} m-K6y7t  
catch(IOException e){e.printStackTrace ();} _IGQ<U<z  
catch(Exception e){e.printStackTrace ();} aG!!z>  
} ^?,/_3  
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private void processErrorCode(int nErrorCode) ax$0J|}7  
{ cuHs`{u@P  
System.err.println("Error Code : " + nErrorCode); y}|zH  
} +VfJ:[q  
7~ 2X/  
%PQC9{hUy$  
//停止文件下载 N4r`czoj  
public void siteStop() lVtgg?  
{ 8K$:9+OY  
bStop = true; Sx}h$E:  
for(int i=0;i<nStartPos.length;i++) `8Gwf;P1  
fileSplitterFetch.splitterStop(); LY"/ Q  
[}Nfs3IlBw  
(jXgJ" m  
} ?tOzhrv  
} ;2$^=:8  
//负责部分文件的抓取 ky*-_  
**FileSplitterFetch.java F4@h}T5)  
*/ ][9M_.  
package NetFox; nt4>9;  
+IU]=qS  
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import java.io.*; RNPqW,B!0  
import java.net.*; R8axdV9(  
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public class FileSplitterFetch extends Thread { <I}k%q'  
mu*wX'.'  
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String sURL; //File URL 5(,
WN  
long nStartPos; //File Snippet Start Position tFRWxy[5  
long nEndPos; //File Snippet End Position V'_^g7}l&  
int nThreadID; //Thread's ID 4aGHks8Z,\  
boolean bDownOver = false; //Downing is over #fwG~Q(  
boolean bStop = false; //Stop identical Ts^IA67&<  
FileAccessI fileAccessI = null; //File Access interface H|Eu,eq-E  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1=s%.0  
{ ]+oPwp;il  
this.sURL = sURL; p%n}a%%I  
this.nStartPos = nStart; HYtkSsXLN  
this.nEndPos = nEnd; 0 {w?u%'  
nThreadID = id; t4nAy)I)P  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %_5B"on  
} %H:!/'45  
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public void run() gB?#T  
{ o zv><e#  
while(nStartPos < nEndPos && !bStop) Lq yY??\@  
{ XI pXP,Yy  
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try{ z}Xn>-N-  
URL url = new URL(sURL); ?g!py[CrE  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l(
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httpConnection.setRequestProperty("User-Agent","NetFox"); h!$W^Tm2g  
String sProperty = "bytes="+nStartPos+"-"; :?&N/7  
httpConnection.setRequestProperty("RANGE",sProperty); 7D4P=$UJp  
Utility.log(sProperty); }F-WOQ  
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InputStream input = httpConnection.getInputStream(); m(?M]CH(A  
//logResponseHead(httpConnection); A|jaWZM-  
"=HCP,  
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byte[] b = new byte[1024]; <V9L AWeS  
int nRead; 9Y~A2C  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <s  $~h  
{ d!8`}L:=M  
nStartPos += fileAccessI.write(b,0,nRead); ]XU?Wg  
//if(nThreadID == 1) +DksWbD  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }9jy)gF*e  
} qbmy~\ZY  
C";F's)  
Qu!Lc:oM?  
Utility.log("Thread " + nThreadID + " is over!"); nKch_Jb
 
bDownOver = true; :v=Yo  
//nPos = fileAccessI.write (b,0,nRead); <kt,aMw[*  
} (eSa{C\  
catch(Exception e){e.printStackTrace ();} R
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} F.K7w  
} m@)K]0g<f  
5
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//打印回应的头信息 5|";L&`  
public void logResponseHead(HttpURLConnection con) q*,];j/>k  
{ YcT!`B  
for(int i=1;;i++) &ciU`//`  
{ ]k5l]JB  
String header=con.getHeaderFieldKey(i); /wVrr%SN  
if(header!=null) ?$v#;n?@I  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); h`,dg%J*B  
Utility.log(header+" : "+con.getHeaderField(header)); [<7Hy,xr_  
else cOq^}Ohan  
break; _da>=^hFJ  
} Kr!8H/Z
  
} Xh;Pbm|K  
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public void splitterStop() y#o ,Vg*V  
{ 6*le(^y`  
bStop = true; )k{zRq:d  
} (pNA8i%=G  
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} eo4;?z  
9=89)TrY  
/w$<0hH#'8  
/* ]G#og)z4  
**FileAccess.java t?iCq1  
*//文件访问(定位，写) v=$v*W  
package NetFox; ]z;%%'gW6  
import java.io.*; p=V (_  
vE
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public class FileAccessI implements Serializable{ Tn8Z2iC  
FT!|YJz<K  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 KFvNsqd  
RandomAccessFile oSavedFile; I6ffp!^}Y  
long nPos; 2'$p(  
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<sE0426
{  
public FileAccessI() throws IOException @.6l^"L  
{ c%n[v3]  
this("",0); <H::
{  
} !7]4sXL{  
80U07tJ  
hlWTsi4N  
public FileAccessI(String sName,long nPos) throws IOException Xkk m~sM6  
{ eYLeytF]Uy  
oSavedFile = new RandomAccessFile(sName,"rw"); |t5K!?{i  
this.nPos = nPos; E`}KVi57
 
oSavedFile.seek(nPos); #XE`8$  
} E=+v1\t)]  
a=>PGriL  
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public synchronized int write(byte[] b,int nStart,int nLen) bsO7
8a~=P  
{ Ii_X^)IL(  
int n = -1; fH-V!QY
GF  
try{ TL lR"L5  
oSavedFile.write(b,nStart,nLen); #8H  
n = nLen; Ze[ezu  
} (sSMH6iCif  
catch(IOException e) { AdPC?R`  
{ gpB3\  
e.printStackTrace (); Q&S\?cKe  
} $yS7
u  
~_OtbNj#  
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return n; R/&Bze  
} ,{!~rSq-l  
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} #Y6'Q8gf  
#0V$KC*>  
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/* M}MXR=X,  
**SiteInfoBean.java O:3LA-vA  
*/ ve;#o<  
package NetFox; zBg>I=hiG  
fS+Ga1CsH  
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public class SiteInfoBean { bq{":[a  
U2l7@uDr;  
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private String sSiteURL; //Site's URL ('BFy>@  
private String sFilePath; //Saved File's Path OLp;eb1g  
private String sFileName; //Saved File's Name J-yj&2  
private int nSplitter; //Count of Splited Downloading File {U/a h2*  
hDTiXc  
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public SiteInfoBean() 7/%{7q3G>  
{//nSplitter的缺省值为5 oju)8
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//default value of nSplitter is 5 bAS('R;4  
this("","","",5); oVk*G  
} '_!j9A]g  
#
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!.9pV.~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }#va#Nb(,  
{ #-?C{$2I  
sSiteURL= sURL; 0]%0wbY1  
sFilePath = sPath; jSNUU.lur  
sFileName = sName; szW_cjS  
this.nSplitter = nSpiltter; b/65Q&g'  
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KKpO<TO  
} @=4K%
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public String getSSiteURL() [gI;;GW  
{ ClZ:#uMbN  
return sSiteURL; owHV&(Go(B  
} 5=]q+&y\H  
r;m_@*]  
V8AF;1c?-'  
public void setSSiteURL(String value) CZaUrr  
{ evOyTvc  
sSiteURL = value; qOOF]L9r%u  
} "BSSA%u?c  
i Lr*W#E  
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public String getSFilePath() ZuF"GNUC  
{ g%z'#E97  
return sFilePath; }@Rq'VPZd  
} P5 fp!YF  
?M?S+@(  
"A\.`*6  
public void setSFilePath(String value) Q(Q.(  
{ K6"#&0  
sFilePath = value; ::bK{yZm  
} rz/^_dV  
A0Z<1|6r*  
&+F|v(|r  
public String getSFileName() . !gkJ  
{ LS1r}cl  
return sFileName; 022nn-~  
} mY[s2t  
g+shz{3zvz  
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public void setSFileName(String value) #m 2Ss  
{ AL*P2\8  
sFileName = value; %J)n#\  
} P%HvL4R  
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4?Mb>\n%<^  
public int getNSplitter() w D|p'N  
{ pbg[\UJyd  
return nSplitter; ch2Qk8  
} H(f~B<7q  
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(pY'v/a-  
public void setNSplitter(int nCount) w#V{'{DKp  
{ zQY|=4NP  
nSplitter = nCount; N~I2~f  
} Qn`$xY9mT  
} iaShxoIV  
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}Ej^M~Vv  
/* 00s&<EM  
**Utility.java ="%nW3e@  
*/ mDJF5I  
package NetFox; 0XwDk$l<  
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public class Utility { m$glRs @  
E+XpgR
5  
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public Utility() (`V  
{ f n]rMH4>  
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@ s   
} h4@v.GI  
CE :x;!}cd  
//线程睡眠 WH`E=p^x4  
public static void sleep(int nSecond) pUs:r0B  
{ {a>a?fVU  
try{ (dSf>p r2  
Thread.sleep(nSecond); H
8^U!"~E  
} IYtM'!u  
catch(Exception e) 4=]CAO=O  
{ CH |A^!Zm  
e.printStackTrace (); OGmOk>_  
} Z7 \gj`  
} zk)9tm;i{  
Q_p!;3  
//日志 7D5;lM[_  
public static void log(String sMsg) v0pyyUqS  
{ 5_4Y/2_|  
System.err.println(sMsg); \etuIFQ#U  
} hD OEJ  
I%dFVt@  
S;0,UgB
1  
public static void log(int sMsg) Q)"L8v v  
{ e;LJdd  
System.err.println(sMsg); WJH)>4M#  
} U}
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} A0L&p(i  
q2qbbQ6H  
K \?b6;ea  
/* uXxc2}  
**TestMethod.java ^G5BD_  
*/ o_un=ygU  
package NetFox; ,`<w#  
3hzI6otKS  
Ave{ `YD  
public class TestMethod { 7|~j=,HU+Z  
3:q\]]]S  
%m8;Lh-X  
public TestMethod() XS!mtd<q  
{ ///xx/weblogic60b2_win.exe 5o2W[<%v  
try{ B?}ZAw>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &?.k-:iN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); E_VLI'Hn?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .gmNE$d  
fileFetch.start(); JN5<=x5r  
} _ZgIm3p0A  
catch(Exception e){e.printStackTrace ();} GWs[a$|  
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.(!> *ka|  
} U p1&(
 
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f< A@D"m/  
public static void main(String[] args) A0x"Etbw)  
{ |T53m;D  
new TestMethod(); ],rtSUO  
} d',OQ,~{  
} zE"ME*ou  
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