http断点续传简单实现（java)

/* q;co53.+P)  
**SiteFileFetch.java UUb n7&  
*/ K"~Tk`[0Q  
package NetFox; VA4>!t)  
import java.io.*; J[E_n;d1  
import java.net.*; {z)&=v@  
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public class SiteFileFetch extends Thread { O^fg~g X  
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SiteInfoBean siteInfoBean = null; //文件信息Bean *Z0Y:"  
long[] nStartPos; //开始位置 6{h+(|.(  
long[] nEndPos; //结束位置 &0B<iO<f  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 d&S4`\g?
8  
long nFileLength; //文件长度 /*g9drwaa  
boolean bFirst = true; //是否第一次取文件 ~"\qX+  
boolean bStop = false; //停止标志 08)X:@ w?  
File tmpFile; //文件下载的临时信息 mmk]Doy?#  
DataOutputStream output; //输出到文件的输出流 [Xp{ztGE  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [$; \1P/  
public SiteFileFetch(SiteInfoBean bean) throws IOException z{h#l!Edh  
{ `J*~B  
siteInfoBean = bean; L<'8#J[_5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); OO%<~H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Hx;ij?  
if(tmpFile.exists ()) gucd]VH  
{ Lg[v-b=?I  
bFirst = false; QF^_4Yn  
read_nPos(); qk}(E#.>F\  
} 'qD5  
else ogN/zIU+VA  
{ zqEMR>px  
nStartPos = new long[bean.getNSplitter()]; Uh.XL=wY  
nEndPos = new long[bean.getNSplitter()]; +<p?i]3CHe  
} -QH[gi{%`  
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} *"rgK|CM$  
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public void run() @V$,H/v:
 
{ C+{du^c$  
//获得文件长度 *We.?"X'].  
//分割文件 ?O1:-vpZ  
//实例FileSplitterFetch qGndh  
//启动FileSplitterFetch线程 g8+w?Zn}  
//等待子线程返回 p#vZYwe=L  
try{ F8*e  
if(bFirst) Eyw)f>  
{ HVb9YU+  
nFileLength = getFileSize(); i!zh9,i>M  
if(nFileLength == -1) L||_
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{ 5+
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System.err.println("File Length is not known!"); (nP 6Xq  
} SB5DL_q  
else if(nFileLength == -2) BoZG^  
{ ]7WBoC8  
System.err.println("File is not access!"); ?3:OPP`s  
} |&ISZFSv  
else F|._'i+B!  
{ gcImk0NIY  
for(int i=0;i<nStartPos.length;i++) p/V  
{ +3VDapfin  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `Pj7O/!)#!  
} p%304oP6  
for(int i=0;i<nEndPos.length-1;i++) zGz^T  
{ :SxOQ(n  
nEndPos = nStartPos[i+1]; a/@<KnT  
} Sz0M8fYT]  
nEndPos[nEndPos.length-1] = nFileLength; e2#"o{+@  
} wv,,#P  
} (]'Q!MjGa  
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//启动子线程 \ iL&Aq}BO  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Qy ; M:q  
for(int i=0;i<nStartPos.length;i++) ?D
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{ f_1#>]  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L2ePWctq}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !Ju?REH  
nStartPos,nEndPos,i); 2A3;#v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \Cx) ~bq<  
fileSplitterFetch.start(); <YbOO{  
} $)| l#'r  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W(*:8}m,p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); e_J_rx  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]pLQ;7f7D  
nEndPos = " + nFileLength); cmDskQ:  
// fileSplitterFetch[nPos.length-1].start(); E-,74B&H  
A.9,p  
W>b(hVBE  
//等待子线程结束 &]~z-0`$!  
//int count = 0; @+",f]  
//是否结束while循环 G'XlsyaWrb  
boolean breakWhile = false; bw#z
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9H*$3  
while(!bStop) &fYx0JT  
{ b5YjhRimS  
write_nPos(); S~
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Utility.sleep(500); UTQ$sg|7p  
breakWhile = true; ~p~8T  
+3e(psdg  
]B>Y +  
for(int i=0;i<nStartPos.length;i++) b?-%Uzp<  
{ 5YIiO7@4  
if(!fileSplitterFetch.bDownOver) +MC>?rr_u  
{ K5(?6hr;  
breakWhile = false; e,Xvt5  
break; uR"srn;^  
} puS'9Lpp  
} 7Z>u|L($m  
if(breakWhile) GCrh4rxgg  
break; |0(Z)s,  
b:7;zOtF  
i;^ e6A>  
//count++; 64}Oa+*s  
//if(count>4) M;W{A)0i1  
// siteStop(); 9\*xK%T+  
} CogLo&.  
=mCUuY#  
j'-akXo<  
System.err.println("文件下载结束！"); JnCY O^Qj  
} .LafP}%  
catch(Exception e){e.printStackTrace ();} f+0dwlIlC$  
} iR4CY-  
9>psQ0IRvr  
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//获得文件长度 GFvZdP`s4  
public long getFileSize() , j,[4^  
{ '6{q;Bxo  
int nFileLength = -1; 1rC8]M.N  
try{ Ig1cf9 :  
URL url = new URL(siteInfoBean.getSSiteURL()); H;,cUb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5(>m=ef"  
httpConnection.setRequestProperty("User-Agent","NetFox"); lfu1PCe5  
^BjwPh4Z#  
DVD}  
int responseCode=httpConnection.getResponseCode(); ~!]FF}6  
if(responseCode>=400) :<%K6?'@^  
{ !.L%kw7z  
processErrorCode(responseCode); [7]p\'j  
return -2; //-2 represent access is error |LKhT4rE  
} .CI]8O"3y  
~=%eOoZP;c  
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String sHeader; D>c%5h  
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for(int i=1;;i++) 2Iz@lrO6  
{ T~Jl{(s9)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =b,$jCv<,5  
//Utility.log(in.readLine()); [?W3XUJ,Y  
sHeader=httpConnection.getHeaderFieldKey(i); x{~-YzWho  
if(sHeader!=null) 5gI@~h S  
{ xpFu$2T6P.  
if(sHeader.equals("Content-Length")) e}/c`7M  
{ UuT>qWxQ8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .EH^1.|v  
break; i[d-n/)  
} KBzEEvx/$  
} 6luCi$bL  
else )QaJYC^+  
break; qChS} Q  
} J~ v<Z/gm  
} ]G&?e9OA  
catch(IOException e){e.printStackTrace ();} jb)z[!FbM  
catch(Exception e){e.printStackTrace ();} P>L-,R(7e  
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Utility.log(nFileLength); "rc}mq  
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return nFileLength; (5-"5<-@R  
} `;*=2M<c  
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]9zc[_ !  
//保存下载信息（文件指针位置） a>sUq["  
private void write_nPos() `Lm ArW:  
{ B_`A[0H  
try{ 4OCz:t  
output = new DataOutputStream(new FileOutputStream(tmpFile)); LLgN%!&  
output.writeInt(nStartPos.length); ,0<|&D  
for(int i=0;i<nStartPos.length;i++) QEUg=*3W=  
{ }5OlX  
// output.writeLong(nPos); Podm 3b  
output.writeLong(fileSplitterFetch.nStartPos); +qpD>5#  
output.writeLong(fileSplitterFetch.nEndPos); ~ ;)@a  
} #k)G1Y[c  
output.close(); .eZ4?|at.F  
} jc;&g)Rv  
catch(IOException e){e.printStackTrace ();} !SiZA"  
catch(Exception e){e.printStackTrace ();} <6p{eGAQV  
} QwOQS %  
6J
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/CKkT.Le  
//读取保存的下载信息（文件指针位置） xkUsZ*X8B  
private void read_nPos() Ofqe+C  
{ '.WYs!  
try{ ?]kIztH  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4,H}'@Db}  
int nCount = input.readInt(); q7 Uu 8JXF  
nStartPos = new long[nCount]; ?Dd2k%o  
nEndPos = new long[nCount]; hpWAQ#%oHm  
for(int i=0;i<nStartPos.length;i++) ]N1$ioC#  
{ +t.T+` EG  
nStartPos = input.readLong(); 56?U4wj7{  
nEndPos = input.readLong(); a;*&q/{o  
} 8Mws?]\/q  
input.close(); \jq1F9,  
} *I'O_D  
catch(IOException e){e.printStackTrace ();} .vQ2w  
catch(Exception e){e.printStackTrace ();} Yz-b~D/=}  
} J9poqp@`MG  
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private void processErrorCode(int nErrorCode) Kh<v2  
{ ;1{S"UY  
System.err.println("Error Code : " + nErrorCode); N@Slc 0  
} 2Y 6/,W  
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//停止文件下载 #J2856bzS  
public void siteStop() j?w7X?1(  
{ D ?,P\cp  
bStop = true; |r0j>F
 
for(int i=0;i<nStartPos.length;i++) /^/'9}7  
fileSplitterFetch.splitterStop(); webT
 
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 PJkMn  
} |C>Yd*E,C  
} H7qda'%>  
//负责部分文件的抓取 VJ_E]}H  
**FileSplitterFetch.java 9Eg'=YJ  
*/ Wt8;S$!=R  
package NetFox; LfgR[!  
2vj)3%:7#E  
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import java.io.*; xu+wi>Y^  
import java.net.*; NSHlo*)}  
iy$]9Wf6=@  
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public class FileSplitterFetch extends Thread { ;'gzRC  
q%>L/KJ#  
!7%L%~z^  
String sURL; //File URL 4,$x~m`N  
long nStartPos; //File Snippet Start Position C?hw$^w7T  
long nEndPos; //File Snippet End Position Q~-gtEv+&  
int nThreadID; //Thread's ID 7;|6g8=  
boolean bDownOver = false; //Downing is over ;PS[VdV  
boolean bStop = false; //Stop identical dC,F?^  
FileAccessI fileAccessI = null; //File Access interface uu#ALB Jm  
zKiKda%)  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException |dX#4Mq^,  
{ d6hWmZVC  
this.sURL = sURL; P\N`E?lJL  
this.nStartPos = nStart; g-*@I`k[  
this.nEndPos = nEnd; 3QV|@5L`[  
nThreadID = id; .'.|s?s  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 sF|<m)Kt{W  
} zhN'@Wj'_  
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public void run() OSkZW  
{ sBRw#xyS  
while(nStartPos < nEndPos && !bStop) ,HMB
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{ 4qyL' \d[  
@9vz%1B<l  
e
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try{ ]^Q`CiKd  
URL url = new URL(sURL); x5PQ9Bw,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "F%cn@l  
httpConnection.setRequestProperty("User-Agent","NetFox"); vRT1tOQ$  
String sProperty = "bytes="+nStartPos+"-"; e?Cbl'
 
httpConnection.setRequestProperty("RANGE",sProperty); (V e[FhA  
Utility.log(sProperty); =BX<;vU  
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7J>n;8{%?  
InputStream input = httpConnection.getInputStream(); lZ_i~;u4@v  
//logResponseHead(httpConnection); 37lmB '~  
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byte[] b = new byte[1024]; YToRG7X#  
int nRead; vZXyc*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) VnIJ$5Y  
{ q~l&EH0  
nStartPos += fileAccessI.write(b,0,nRead); .}CPZ3y  
//if(nThreadID == 1) IS'=%qhC`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #;^.&2Lt  
} PeE'#&wn  
~D
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\".3x PkE  
Utility.log("Thread " + nThreadID + " is over!"); a_x|PbD  
bDownOver = true; RqcX_x(p  
//nPos = fileAccessI.write (b,0,nRead); gCwg ;c-  
} 9*,5R,#  
catch(Exception e){e.printStackTrace ();} ld2\/9+n  
} Gm>8= =c  
} Bxm^Arc>  
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y4shW|>5_  
//打印回应的头信息 %AW  
public void logResponseHead(HttpURLConnection con) #j;&g1  
{ |0-5-.  
for(int i=1;;i++) O[`n{Vl/  
{ y f+/Kj< a  
String header=con.getHeaderFieldKey(i); ]Fjz+CGg  
if(header!=null) 9"<)DS  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <'B`b  
Utility.log(header+" : "+con.getHeaderField(header)); S)Ld^0w  
else V?5_J%  
break; J-I7K!B  
} L'['7  
} dmE-WS  
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public void splitterStop() M{z+=c&w  
{ GbNVcP.ocP  
bStop = true; Re.fS6y$>  
} T8qG9)~3  
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} Lw!@[;2  
1>|p1YZ"  
8vaqj/  
/* MK=:L  
**FileAccess.java v3@)q0@  
*//文件访问(定位，写) k,q` ^E8k  
package NetFox; O gycP4z[  
import java.io.*; ~8|$KD4I  
][qZOIk@  
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public class FileAccessI implements Serializable{ {OQ sGyR?  
q .?D{[2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 #UGbSOoCtn  
RandomAccessFile oSavedFile; oA42?I ^  
long nPos; 8SKDL[rN  
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zHx?-Q&3  
public FileAccessI() throws IOException Bpqq-_@  
{ xp,H5 m%  
this("",0); j[Et+V?  
} )ns;S  
6|9];)  
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public FileAccessI(String sName,long nPos) throws IOException 1hRC Bwx  
{ \3Xt\1qN4  
oSavedFile = new RandomAccessFile(sName,"rw"); 3btciR!N]  
this.nPos = nPos; lz# inC|  
oSavedFile.seek(nPos); Dcp,9"yt%  
} 0jg-]  
A)VOv`U@2  
oM< &4F  
public synchronized int write(byte[] b,int nStart,int nLen) x&8?/BR  
{ ~%sDQt\S  
int n = -1; OGae]O<  
try{ ^(6.P)$  
oSavedFile.write(b,nStart,nLen); 4I2ppz   
n = nLen; zM)o^Fn2  
} UB(8N7_/  
catch(IOException e) r4_ c~\jH  
{ ~%GUc ~  
e.printStackTrace (); 5a_K|(~3I  
} _39b8s{  
1M<'^(t3d  
@Yt[%tOF+  
return n; Lp{l&-uQ  
} ,',fO?Qv'  
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.>H7i`1D`  
} 4$y|z{[< 5  
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/* /j.V0%  
**SiteInfoBean.java ?{^T&<18t  
*/ ."=Bx2  
package NetFox; BfhOe~+i  
1FY^_dvH  
Fv(zql  
public class SiteInfoBean { 7eu7ie6  
EI/_=.d  
2#|Q=rWB  
private String sSiteURL; //Site's URL LR`/pet  
private String sFilePath; //Saved File's Path aP4r6lLv+  
private String sFileName; //Saved File's Name N(F9vZOs  
private int nSplitter; //Count of Splited Downloading File VpJ
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GL (YC-{  
II[qWs>RG[  
public SiteInfoBean() YJr@4!j*  
{//nSplitter的缺省值为5 TrHBbyqk  
//default value of nSplitter is 5 PRf2@0
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this("","","",5); \d v9:X$  
} 4?d2#Xhs8  
G =lC[i  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (\SxG\`  
{ <4Ujk8Zj  
sSiteURL= sURL; |ukEnjI`u  
sFilePath = sPath; )8P<ZtEU  
sFileName = sName; V_Y SYG9f  
this.nSplitter = nSpiltter; !QC->  
N!H
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'm-s8]-W  
} Vwl`A3Y  
bC"#.e  
u QCQ$  
public String getSSiteURL() ;:'A{&0N  
{ PBkKn3P3  
return sSiteURL; Fet>KacTht  
} o2Z# 5-  
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public void setSSiteURL(String value) fq\E$'o$  
{ $g#%  
sSiteURL = value; Soq 'B?>  
} oSTGs@EK  
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~0ZP%1.B3  
public String getSFilePath() 6i>xCb  
{ wYS
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return sFilePath; n?:s/6tP  
} e'g-mRh  
z`{Ld9W  
@YV-8;hO  
public void setSFilePath(String value) 7FfzMs[\e  
{ /z~;.jRg  
sFilePath = value; <BT}Tv9  
} N{oD1%  
b+3{ bE  
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public String getSFileName()
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{ 6Pd;I,k  
return sFileName; Hz+edMUL  
} 7pr@aA"vgj  
* 4
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public void setSFileName(String value) kg9ZSkJr  
{ |P~TZ  
sFileName = value; XCQ=`3f  
} LLV:E{`p  
<C]s\"o-`  
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public int getNSplitter() 6fQQKM@a|  
{ vvdC.4O  
return nSplitter; W aks*^|  
} :'a |cjq  
>L5[dkg%  
lHr?sMt
 
public void setNSplitter(int nCount) /ey}#SHm,  
{ 8 w^i  
nSplitter = nCount; \*a7DuVw  
} @k~Xem%<  
}  :\gdQG  
;h3c+7u1  
&P,8)YA  
/* wVV'9pw}  
**Utility.java If2f7{b  
*/ _ jF, k>F  
package NetFox; YDdmT7Ow  
m[(2  
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public class Utility { <5?.
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m03;'Nj'7#  
AfFFu\  
public Utility() _Su$oOy(Ea  
{ 8^^Xr  
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} )0~zL} )?  
gz Qc  
//线程睡眠 ,7z.%g3+z  
public static void sleep(int nSecond) Kcl>uAgU  
{ ( *UMpdj  
try{ 6# ,2  
Thread.sleep(nSecond); UC\CCDV#^  
} Gpo(Zf?  
catch(Exception e) $hn#T#J3  
{ 4*G#fW-  
e.printStackTrace (); Mp}aJzmkB;  
} j^mAJ5  
} g]N!_Ib/!  
Z2j M.[hq  
//日志 *Xn{{  
public static void log(String sMsg) *oKc4S+  
{ b~WiE?  
System.err.println(sMsg); bK<'J=#1  
} Mb"i}Yt{  
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m ['UV2  
public static void log(int sMsg) \Om.pOz  
{ N
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System.err.println(sMsg); nV@k}IJg:?  
} @y2{LUJe  
} 9)];l?l  
Myg &H(~  
n2Q~fx<6%  
/* CcG{+-=H)  
**TestMethod.java "+~La{POc  
*/ mi`!'If0)  
package NetFox; :Bz*vH  
~K&ko8  
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public class TestMethod { -}AAA*P  
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&k+jVymH  
public TestMethod() BRi\&&<4  
{ ///xx/weblogic60b2_win.exe 0P3^#j  
try{ s["8QCd"r  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); x4r\cL1!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,73J#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); s9>-Q"(y  
fileFetch.start(); &$
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} jO&sS?  
catch(Exception e){e.printStackTrace ();} I'Ui` :A  
-iLp3m<ai  
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} fb0i6RC~&  
2/
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V\5ZRLawP  
public static void main(String[] args) >TK:&V  
{ BGh1hyJ8d  
new TestMethod(); \vjIw{   
} iO4Yfj#?  
} h8iic  
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