http断点续传简单实现（java)

/* gIWrlIV{9  
**SiteFileFetch.java n;HHogA  
*/ X#xFFDzN  
package NetFox; 6SJ"Tni8  
import java.io.*; Hi!Jj  
import java.net.*; zxb/  
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public class SiteFileFetch extends Thread { yAT^VRbv  
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SiteInfoBean siteInfoBean = null; //文件信息Bean =*BIB
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long[] nStartPos; //开始位置 Zt -1h{7  
long[] nEndPos; //结束位置 qM4c]YIaSl  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _Jz8{` "  
long nFileLength; //文件长度 4P
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boolean bFirst = true; //是否第一次取文件 zo{/'BnU  
boolean bStop = false; //停止标志 Agh`]XQ2  
File tmpFile; //文件下载的临时信息 +1JH  
DataOutputStream output; //输出到文件的输出流 U=Y)V%  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ->z54 T  
public SiteFileFetch(SiteInfoBean bean) throws IOException BC>=B@H0  
{ L(S'6z~_9  
siteInfoBean = bean; Xy,lA4IP  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Bm$"WbOq*R  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Xm2\0=v5;  
if(tmpFile.exists ()) 2Q7R6*<N:  
{ 'XQ`g CF=  
bFirst = false; ] H~4  
read_nPos(); Kemw^48ts  
} zIC;7 5#  
else zQ?!f#f  
{ B0$:b!  
nStartPos = new long[bean.getNSplitter()]; +[@z(N-h  
nEndPos = new long[bean.getNSplitter()]; !1T\cS#1%  
} @5
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} @}_WE,r  
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public void run() j hYToMq  
{ y4Z&@,_{  
//获得文件长度 vr#+0:|  
//分割文件 dG QG!l+>  
//实例FileSplitterFetch -50HB`t  
//启动FileSplitterFetch线程 H>Q%"|  
//等待子线程返回 AWjJ{#W>9  
try{ Vt^3iX{!  
if(bFirst) h'J|K^na  
{ mS>xGtD&K  
nFileLength = getFileSize(); U<"WK"SM  
if(nFileLength == -1) ^ PI
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{ U~{du;\  
System.err.println("File Length is not known!"); "gd=J_Yw  
} qbrpP(.  
else if(nFileLength == -2) Er/bO  
{ 4v p  
System.err.println("File is not access!"); kK8itO  
} IcP)FB4  
else $,I q;*7N  
{ zX5!vaEv  
for(int i=0;i<nStartPos.length;i++) jR=s#Xz  
{ *"9><lJ-!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); a`Gx=8  
} MT(o"ltQ  
for(int i=0;i<nEndPos.length-1;i++) %0#1t 5g  
{ +% /s*EC'w  
nEndPos = nStartPos[i+1]; fQrhsuCrC  
} Z\[N!Zt|  
nEndPos[nEndPos.length-1] = nFileLength; q'pK,uNW  
} ld$i+6|   
} 1+b{}d  
k6`6Mjbc  
|AZg*T3:W  
//启动子线程 j4=(H:c~E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (}.@b|s  
for(int i=0;i<nStartPos.length;i++) sNun+xsf^  
{ A+@&"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $R<Me  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {M,,npl  
nStartPos,nEndPos,i); -}K<ni6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t|t#vcB  
fileSplitterFetch.start(); rD>*j~_+P  
} =PGs{?+&O  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;lYHQQd!,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); L(GjZAP  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", O25lLNmO  
nEndPos = " + nFileLength); tabT0  
// fileSplitterFetch[nPos.length-1].start(); ;Eu3[[V  
y qtKy  
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//等待子线程结束 8p[)MiC5W^  
//int count = 0; ){jla,[  
//是否结束while循环 x@8a''  
boolean breakWhile = false; h gJ[LU|>  
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while(!bStop) g^zs,4pPU<  
{ G:g69=x y  
write_nPos(); $XoQ]}"O  
Utility.sleep(500); |Ph3#^rM?  
breakWhile = true; !?Wp+e6  
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for(int i=0;i<nStartPos.length;i++) W`^@)|9^)  
{ eYx Kp!f  
if(!fileSplitterFetch.bDownOver) s(W|f|R  
{ F2X0%te  
breakWhile = false; # W"=ry3{  
break; fFQ|T:vm  
} #c2ymQm  
} 4`,j=3  
if(breakWhile) 47J5oPT2'  
break; qP<Lr)nUH  
']+Uu'a  
$ `7^+8vHV  
//count++; zXRlo]  
//if(count>4) W^"AU;^V56  
// siteStop(); 4>J   
} H/}]FmjN  
 W%\C_  
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System.err.println("文件下载结束！"); IsR!'%Pu  
} TsTPj8GAl[  
catch(Exception e){e.printStackTrace ();} _o8?E&d  
} <I;2{*QI2  
)m. 4i=X  
0V?F'<qy  
//获得文件长度 V*~Zs'L'E  
public long getFileSize() j)q\9#sI/(  
{ W6Y@U$P#G  
int nFileLength = -1; jmeRrnC}  
try{ }}<z/zN&^  
URL url = new URL(siteInfoBean.getSSiteURL()); l}qE 46EL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Sf8{h|71  
httpConnection.setRequestProperty("User-Agent","NetFox"); M'/aZ# b  
i7ly[6{^pr  
n93=8;&  
int responseCode=httpConnection.getResponseCode(); #^]n0!  
if(responseCode>=400) 1UQHq@aM  
{ yxc=Z0~1  
processErrorCode(responseCode); LCQE_}Mh  
return -2; //-2 represent access is error [pM V?a[  
} 4 uQT5  
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String sHeader; (IPY
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for(int i=1;;i++) ZIF49`Y4TF  
{ +}a ]GTBgA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !*OJ.W&  
//Utility.log(in.readLine()); Y5j]Z
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sHeader=httpConnection.getHeaderFieldKey(i); *<!oHEwkN  
if(sHeader!=null) )Dz+X9;g+  
{ fYW6b[
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if(sHeader.equals("Content-Length")) |ely|U. Tf  
{ F_4n^@M  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); y TDNNK  
break; :Q@&5!]>d  
} 9WR6!.y#f  
} ~_!F0
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else u#@Q:tnN_  
break; yR\btx|e5~  
} SZXY/~=h  
} 2j&AiD  
catch(IOException e){e.printStackTrace ();} R`~z0d.  
catch(Exception e){e.printStackTrace ();} fX|Y;S-@+  
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Utility.log(nFileLength); ,11H.E Z  
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return nFileLength; TU 1I} ,  
} (/j); oSK  
o+$7'+y1n-  
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//保存下载信息（文件指针位置） = MOj|NR [  
private void write_nPos() (#E.`e1#6  
{  ({=gw9f  
try{ 5EfS^MRf\n  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^!by3Elqqk  
output.writeInt(nStartPos.length); BV[5}  
for(int i=0;i<nStartPos.length;i++) GHeVp/u  
{ w:<W.7y?0  
// output.writeLong(nPos); aqc?pqM  
output.writeLong(fileSplitterFetch.nStartPos); UQI]>#_/v  
output.writeLong(fileSplitterFetch.nEndPos); )6J9J+%bi  
} ZKckAz\#  
output.close(); y7i*s^ys{  
} !!? Mw  
catch(IOException e){e.printStackTrace ();} 1cD! :[  
catch(Exception e){e.printStackTrace ();} vt9)pMs  
} wD]/{
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//读取保存的下载信息（文件指针位置） H?X|(r|+  
private void read_nPos() Ch3jxgQY  
{ 7!JQB
 
try{ |]X  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O|M{-)  
int nCount = input.readInt(); UaB @  
nStartPos = new long[nCount]; q*7VqB  
nEndPos = new long[nCount]; -#HA"7XOE  
for(int i=0;i<nStartPos.length;i++) [+DW >Et  
{ t?'!$6  
nStartPos = input.readLong(); j?x>_#tIY  
nEndPos = input.readLong(); ?}U(3  
} ub\MlSr  
input.close(); /q`xCS  
} Gf<'WQ[  
catch(IOException e){e.printStackTrace ();} @3C>BLI8+  
catch(Exception e){e.printStackTrace ();} ]X ?7ZI^  
} rcC<Zat,|  
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private void processErrorCode(int nErrorCode) 75/(??2  
{ %~E ?Z!_W  
System.err.println("Error Code : " + nErrorCode); Pn>Xbe  
} qfMo7e@6*  
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j;-1J_e5  
//停止文件下载 a@UZb  
public void siteStop() :lPb.UCY  
{ to DG7XN}  
bStop = true; G(G{RAk>  
for(int i=0;i<nStartPos.length;i++) 6MT1$7|P&x  
fileSplitterFetch.splitterStop(); y+c|vdW%  
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} vnM@QfN  
} b2OQtSr a  
//负责部分文件的抓取 KmA;HiH%J  
**FileSplitterFetch.java 6sx'S?Qa*  
*/ 0+kH:dP{  
package NetFox;
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import java.io.*; !`,Sfqij  
import java.net.*; Rld!,t  
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public class FileSplitterFetch extends Thread { ;7E7!t^  
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String sURL; //File URL @,cowar*  
long nStartPos; //File Snippet Start Position V@cM|(  
long nEndPos; //File Snippet End Position 4{rZppm  
int nThreadID; //Thread's ID 0 yuW*z  
boolean bDownOver = false; //Downing is over kt["m.  
boolean bStop = false; //Stop identical 2\jPv`Ia  
FileAccessI fileAccessI = null; //File Access interface g1W.mAA3B  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qB0E_y)a  
{ aTqd@},?  
this.sURL = sURL; ER5gmmVP@p  
this.nStartPos = nStart; &]v4@%<J  
this.nEndPos = nEnd; #Ssx!+q?  
nThreadID = id; |"/8XA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 MGR!Z@1y  
} )4gJd? 8R  
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public void run() ZniB]k1  
{ Li/O  
while(nStartPos < nEndPos && !bStop) zF8dKFE~  
{ s:#V(<J  
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try{ *W0y: 3dB3  
URL url = new URL(sURL); E*V`":efS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #fM#p+v  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8S mCpg  
String sProperty = "bytes="+nStartPos+"-"; ~sl{|E  
httpConnection.setRequestProperty("RANGE",sProperty); OjJXysslXO  
Utility.log(sProperty); -@yh>8v  
7\$qFF-y  
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InputStream input = httpConnection.getInputStream(); ?Z Rs\+{vG  
//logResponseHead(httpConnection); 8/i!' 0r\  
4zev^FR  
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byte[] b = new byte[1024]; *1p|5!4c  
int nRead; NdtB1b  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ej4W{IN~:  
{ =vQcYa  
nStartPos += fileAccessI.write(b,0,nRead); U3T#6Rptl  
//if(nThreadID == 1) zVXC1u9B  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %W%9j#!aN  
} 1|kvPo#  
*)ardZV${  
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Utility.log("Thread " + nThreadID + " is over!"); .y_/Uwu  
bDownOver = true;  tBq nfv  
//nPos = fileAccessI.write (b,0,nRead); iVp,e  
} MBt9SXM  
catch(Exception e){e.printStackTrace ();} clNkph  
} ^r*r w=  
} kPVO?u
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//打印回应的头信息 OY:
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public void logResponseHead(HttpURLConnection con)  ~ ip,Nl  
{ T(t+ iv  
for(int i=1;;i++) 'R c,Mq'  
{ QlJ)F{R8il  
String header=con.getHeaderFieldKey(i); b]x4o#t  
if(header!=null) +n#V[~~8AI  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); _~piZmkG$  
Utility.log(header+" : "+con.getHeaderField(header)); AS\F{ !O  
else Cq'KoN%nQ  
break; rd9e \%A  
} jg.QRny^  
} f ` R/ i  
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public void splitterStop() 4"(<X  
{ -F<Wd/Xse  
bStop = true; fZ*+2T>  
} }[4r4 1[  
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} . koYHq  
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/* 6f\Lf?vF  
**FileAccess.java fpFhn  
*//文件访问(定位，写) T3k#VNH  
package NetFox; SV2M+5#;  
import java.io.*;
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YgUvOyaQXf  
public class FileAccessI implements Serializable{ YbTxn="_  
px}|Mu7z~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 WJ4li@T7V  
RandomAccessFile oSavedFile; [%77bv85.G  
long nPos; cd$m25CxC  
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public FileAccessI() throws IOException tE]
= cTSV  
{ :}@g6   
this("",0); FW/W%^  
} \}p6v}  
/.Ww6a~  
;|vpwB@B
 
public FileAccessI(String sName,long nPos) throws IOException ?e,pN,4  
{ "a8j"lPJ  
oSavedFile = new RandomAccessFile(sName,"rw"); L]a|vp  
this.nPos = nPos; :!hk~#yvJ9  
oSavedFile.seek(nPos); zPA>af~Ej  
} t3M0La&  
_BCT.ual  
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public synchronized int write(byte[] b,int nStart,int nLen) `ITDTZ J  
{ G)K9la<p  
int n = -1; np&HEh 6  
try{ f3\w99\o  
oSavedFile.write(b,nStart,nLen); ?~]>H A:  
n = nLen;
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} rufRaar  
catch(IOException e) cRPr9LfD@  
{ ud
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e.printStackTrace (); CVi<~7Am\  
} rHR5,N:  
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return n; :r[W'h_%  
} Lp~c  
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} )vxVg*.Ee  
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?m`R%>X"  
/* (d1V1t2r6  
**SiteInfoBean.java g
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*/ I]s:Ev[~  
package NetFox; !<JG&9ODP  
AJdlqbd'+  
<$Xn:B<H  
public class SiteInfoBean { u_$6LEp-  
mOgx&ns;j  

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private String sSiteURL; //Site's URL Yf%[6Y{  
private String sFilePath; //Saved File's Path u9da]*\7y  
private String sFileName; //Saved File's Name (2&K(1.Y  
private int nSplitter; //Count of Splited Downloading File uBV^nUjS"m  
:z}~U3,JE  
fte!Ll'  
public SiteInfoBean() %DHP
 
{//nSplitter的缺省值为5 rl_1),J\qG  
//default value of nSplitter is 5 E9 :|8#b  
this("","","",5); u^;sx/  
} xNkwTDN5  
`3H?*\<(
 
,DW0A//  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9'1;-^U1  
{ ~%::r_hQ  
sSiteURL= sURL; JRcuw'8+q  
sFilePath = sPath; f^>lObvd  
sFileName = sName; :$u{  
this.nSplitter = nSpiltter; =[43y%   
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} *+zy\AhkP  
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public String getSSiteURL() {jCu9 ]c!  
{ WL*W=(  
return sSiteURL; KD<; ?oN<O  
} J,&`iL-  
}(hYG"5  
)x5$io   
public void setSSiteURL(String value) tS*^}e*  
{ d(dw]6I6  
sSiteURL = value; -;DE&~p  
} S|Ij q3  
QL|:(QM  
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public String getSFilePath() :@z5& h  
{ R*c0NJF
 
return sFilePath; kAKqW7,q"  
} It,n +
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:[ZC-hc\  
public void setSFilePath(String value) Wy0a2Ve  
{ uk>/Il  
sFilePath = value; D2wgSr
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} \c@qtIc  
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public String getSFileName() e&]`X HC9  
{ R4J>M@-0v  
return sFileName; ."#jN><t  
} m@ 'I|!^  
]FnrbQ|  
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public void setSFileName(String value) 1Qc(<gM  
{ [HZCnO|N  
sFileName = value; Qak@~b  
} :e9jK[)h0  
< c4RmnA  
Wx\"wlJ7.3  
public int getNSplitter() 1Mhc1MU  
{ NByN}e  
return nSplitter; RU ,N_GV
 
} cX]{RVZo-/  
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'9F{.]  
public void setNSplitter(int nCount)
&oEq&  
{ .$x[!fuuR&  
nSplitter = nCount; D8Waf  
} y:``|*+  
} ;[\2/$-  
;<GTtt#D  
.g`*cDW^=  
/* }oxaB9r  
**Utility.java 9P>S[=  
*/  $.]t1e7s  
package NetFox; s&_O2
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public class Utility { 8gKR<X.G  
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public Utility() KI QBY!N+  
{ :XY3TI  
(p
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} '\mZ7.Jj  
$aI MQ[(  
//线程睡眠 vo<#sa^,j  
public static void sleep(int nSecond) fQA)r  
{ : MmXH&yR  
try{ A,[m=9V  
Thread.sleep(nSecond); P FFw$\j  
} ;p"XCLHl  
catch(Exception e) (_5+`YsV  
{ =F-^RnO%\  
e.printStackTrace (); tU2;Wb!Y  
} @Lv_\^2/}  
} ;xH'%W9z  
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//日志 "J:NW_U  
public static void log(String sMsg) &rWJg6/  
{ nhhJUN?8  
System.err.println(sMsg); SF=|++b1f  
} #zD+DBTAu  
* rANf&y  
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public static void log(int sMsg) ul&7hHp_u%  
{ R~(.uV`#j  
System.err.println(sMsg); K'/x9.'%  
} 5|t&qUV  
} #,{v Js~  
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M_)T=s *  
/* r+Cha%&D  
**TestMethod.java DNO%J^  
*/ sb5kexGxkc  
package NetFox; [B<{3*R_  
XArLL5_L  
}}2hI`   
public class TestMethod { 8rNxd=!  
TrAUu`?#  
w2V E_  
public TestMethod() u)MA#p {  
{ ///xx/weblogic60b2_win.exe #!@ ]%4  
try{ 4Lb<#e13R?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &!MKqJ@t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Q:|E  
SiteFileFetch fileFetch = new SiteFileFetch(bean);  >S/>2e:  
fileFetch.start(); '|r!yAO6  
} 5toNEDN  
catch(Exception e){e.printStackTrace ();} KJSy7F  
IrM3Uh  
fE}}>  
} Bqj*{m  
PxY"{-iAM  
5?"ZM'4  
public static void main(String[] args) ^PszZ10T  
{ !4fL|0  
new TestMethod(); b,`N;*  
} LYv2ll`XP  
} CeemR>\t  
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