http断点续传简单实现（java)

/*  !AFii:#  
**SiteFileFetch.java GL'zNQP-  
*/ *Fz#x{zt  
package NetFox; f$]ttU U  
import java.io.*; </33>Fu)  
import java.net.*; ( Y)a`[B  
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public class SiteFileFetch extends Thread { _T(MMc  
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SiteInfoBean siteInfoBean = null; //文件信息Bean #u$Z/,  
long[] nStartPos; //开始位置 A
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long[] nEndPos; //结束位置 kf2e-)uUs  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 x(bM   
long nFileLength; //文件长度 8I%N^G  
boolean bFirst = true; //是否第一次取文件 Xr$hQbl5D  
boolean bStop = false; //停止标志 d{~Qd|<rr  
File tmpFile; //文件下载的临时信息 
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DataOutputStream output; //输出到文件的输出流  :IX_}|  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） .Af H>)E  
public SiteFileFetch(SiteInfoBean bean) throws IOException uW^W/S%'  
{ | sZu1K  
siteInfoBean = bean; ,7*-%05[\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )kK" 1\m  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); vp..>BMJ  
if(tmpFile.exists ()) Wkc^?0p  
{ 5 @61=Au  
bFirst = false; hSfLNvK  
read_nPos(); jS'hs>Ot  
} hv8j$2m  
else P<s:dH"  
{ (h>+ivf|  
nStartPos = new long[bean.getNSplitter()]; (]*!`(_b  
nEndPos = new long[bean.getNSplitter()]; 2Wq/_:  
} 4&'_~qU  
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} "i/3m'<2  
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public void run() 7T@"2WYat  
{ ~n`G>Oe3  
//获得文件长度 \|q.M0  
//分割文件 2Ik@L,  
//实例FileSplitterFetch X^ZUm  
//启动FileSplitterFetch线程 ffE&=eh)  
//等待子线程返回 uq_h8JH$  
try{ |4u?Q+k%%  
if(bFirst) /dt'iai~l  
{ e \ rb  
nFileLength = getFileSize(); |q*s)8  
if(nFileLength == -1) )uIHonXU  
{ 8et.A  
System.err.println("File Length is not known!"); TLiA>`r=  
} B#9T6|2  
else if(nFileLength == -2) ky98Bz%  
{ {;j@-=pV  
System.err.println("File is not access!"); >"z&KZKI  
} >Gyg`L\  
else 4E.K6=k|=a  
{ Il,^/qvIY  
for(int i=0;i<nStartPos.length;i++) C*fSPdg?  
{ b6~MRfx`7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |? l6S
 
} n*U+jc  
for(int i=0;i<nEndPos.length-1;i++) +i.b&PF'H  
{ >!|(n@  
nEndPos = nStartPos[i+1]; ?{M!syD<  
} 9dXtugp|  
nEndPos[nEndPos.length-1] = nFileLength; /"%QIy'{  
} Il9pL~u  
} O`W&`B(*k  
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//启动子线程 &.t|&8-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ;Z(~;D  
for(int i=0;i<nStartPos.length;i++) hSyA;*)U  
{ U?:<clh  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IRW%*W#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), J((
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nStartPos,nEndPos,i); 8{Id+Q>Vo,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Sk 10"DB/  
fileSplitterFetch.start(); Z/@%MEU[zl  
} =#c?g Wb56  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7,N>u8cTh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #Zy-X_r  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", DG $._  
nEndPos = " + nFileLength); d^<a)>5h  
// fileSplitterFetch[nPos.length-1].start(); "x$RTuWA9  
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1@Zjv>jy[  
//等待子线程结束 wh
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//int count = 0; >@o}l:*  
//是否结束while循环 (W l5F  
boolean breakWhile = false; 32*FISH^  
%wp#vO-$  
#815h,nP+  
while(!bStop) @|^2 +K/  
{ \Ow-o0  
write_nPos(); : *Nvy={c  
Utility.sleep(500); hA81(JWG  
breakWhile = true; ToHCS/J59  
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"jUr[X2J  
for(int i=0;i<nStartPos.length;i++) K$..#]\TM  
{ vZns,K#4H\  
if(!fileSplitterFetch.bDownOver) uUczD 8y  
{ R.EA5X|_  
breakWhile = false;
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break; D~xUr)E  
} M7(vI4V  
} 0Up@+R
2  
if(breakWhile) %q@eCN  
break; 2\z
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//count++; .bYDj&]P{  
//if(count>4) M_2[Wypw  
// siteStop(); ~OXC6z  
} PIuk]&L^  
>_biiW~x:  
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System.err.println("文件下载结束！"); .wD>0Ig  
} #(53YoV_8  
catch(Exception e){e.printStackTrace ();} "kKIVlC  
} t/bDDV"  
^#R-_I  

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//获得文件长度 Lj$yGdK<  
public long getFileSize() q)ygSOtj  
{ WRJ+l_81  
int nFileLength = -1; 0O>8DX  
try{ gnoV>ON0  
URL url = new URL(siteInfoBean.getSSiteURL()); W.ud<OKP90  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b\%=mN
 
httpConnection.setRequestProperty("User-Agent","NetFox"); zJ#e3o.  
7"r7F#D=G  
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int responseCode=httpConnection.getResponseCode(); A`7uw|uO$  
if(responseCode>=400) 'r%`(Z{~  
{ N1KYV&'o  
processErrorCode(responseCode); SPIYB/C  
return -2; //-2 represent access is error Lrr^ob
c  
} 2k[i7Rl \c  
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String sHeader; '?5=j1  
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for(int i=1;;i++) Ho?+?YJ#P  
{ Fz16m7.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8=7u,t  
//Utility.log(in.readLine()); XQ<2(}]4  
sHeader=httpConnection.getHeaderFieldKey(i); `OnN12`  
if(sHeader!=null) xyx.1o e!  
{ | zj$p~  
if(sHeader.equals("Content-Length")) YizJT0$  
{ 9oP8| <+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); J?-"]s`J  
break; F]W'spF,  
} YF@'t~_Z  
} !>/U6
h,_  
else HB\y [:E  
break; !cLX1S  
} :>'^l?b'WX  
} w&v_#\T  
catch(IOException e){e.printStackTrace ();} 3skq%;%Wsk  
catch(Exception e){e.printStackTrace ();} TeQWrms  
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Utility.log(nFileLength); O!sZMGF$p  
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return nFileLength; T"t3e=xA  
} +J$[RxQ#  
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hg  
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//保存下载信息（文件指针位置） [e ;K$  
private void write_nPos() SMgf(N3]  
{ XN]kNJX  
try{ :SSe0ZZ_6b  
output = new DataOutputStream(new FileOutputStream(tmpFile)); K|Std)6  
output.writeInt(nStartPos.length); /wI$}X5o~  
for(int i=0;i<nStartPos.length;i++) HPpKti7g  
{ Aa.bE,W  
// output.writeLong(nPos); @6ZQkX/  
output.writeLong(fileSplitterFetch.nStartPos); }Fyf?TZ$T  
output.writeLong(fileSplitterFetch.nEndPos); hkv&Od,  
} R3&W.?C T  
output.close(); a`GoNh,  
} -U"(CGb5  
catch(IOException e){e.printStackTrace ();} -sGfpLy<6  
catch(Exception e){e.printStackTrace ();} R#Id"O  
} sxl29y^*  
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+|Xx=1_?BK  
//读取保存的下载信息（文件指针位置） %`HAg MgP  
private void read_nPos() h5x FP  
{ pF#nj`L  
try{ 3Zdkf]Gh  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >va#PFHA  
int nCount = input.readInt(); w^NE`4 -  
nStartPos = new long[nCount]; `>'E4z]-_  
nEndPos = new long[nCount]; -GCGxC2u  
for(int i=0;i<nStartPos.length;i++) N(]6pG=  
{ LwkZ(Tt  
nStartPos = input.readLong(); ^{-J Y  
nEndPos = input.readLong(); #=5/D@  
} Am!$\T%2  
input.close(); ~0|Hw.OK  
} ,#UaWq@7  
catch(IOException e){e.printStackTrace ();} Tw`^  
catch(Exception e){e.printStackTrace ();} UbJ_'>hK6  
} }!(cm;XA"  
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private void processErrorCode(int nErrorCode) 5X nA.?F^  
{ {G/4#r 2>  
System.err.println("Error Code : " + nErrorCode); ?H0 #{!s  
} OYgD9T.8^  
3F[z]B  
tV@!jaj\  
//停止文件下载 7 \!t/<  
public void siteStop() 7:R8QS9  
{ yiS
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bStop = true; :u
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for(int i=0;i<nStartPos.length;i++) \$V~kgQ0  
fileSplitterFetch.splitterStop(); YT
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} &2Q4{i  
} tV9nC  
//负责部分文件的抓取 I/<aY*R4  
**FileSplitterFetch.java 55Y BO
$  
*/ dMQtW3stY  
package NetFox; ((N<2G)  
?^Q!=W<7  
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import java.io.*; xYRN~nr  
import java.net.*; yK_$6EtNKj  
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public class FileSplitterFetch extends Thread { V"#ie Yn  
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String sURL; //File URL vkOCyi?c  
long nStartPos; //File Snippet Start Position x}i:nLhL  
long nEndPos; //File Snippet End Position H@qA X  
int nThreadID; //Thread's ID b/Z=FS2T  
boolean bDownOver = false; //Downing is over =m:xf&r#  
boolean bStop = false; //Stop identical B5~S&HQ?B6  
FileAccessI fileAccessI = null; //File Access interface ^9%G7J:vGO  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException p}.L]Y  
{ ow!utAF  
this.sURL = sURL; xJa  
this.nStartPos = nStart; -[|R\'i  
this.nEndPos = nEnd; Nj5Mc>_   
nThreadID = id; (q59cAw~X  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 93$'PwWgiF  
} 1\=)b< y  
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public void run() s%2w&Us*  
{ IKMkpX!]  
while(nStartPos < nEndPos && !bStop) y$Sn3_9 V  
{ 3~;LNi  
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try{ $d3al%Uo  
URL url = new URL(sURL); lRF04  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]wMd!.lm-  
httpConnection.setRequestProperty("User-Agent","NetFox"); )gYsg  
String sProperty = "bytes="+nStartPos+"-"; SpU+y|\[0  
httpConnection.setRequestProperty("RANGE",sProperty); O; 7`*}m  
Utility.log(sProperty); ?{NP3  
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InputStream input = httpConnection.getInputStream(); Ly"u }e  
//logResponseHead(httpConnection); eY)ugq>'  
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byte[] b = new byte[1024]; 26.),a  
int nRead; \1cay#X  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) NGcd  
{ SU~t7Ta!G  
nStartPos += fileAccessI.write(b,0,nRead); P$ZIKkf  
//if(nThreadID == 1) l=ehoyER  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~[l6;bn  
} u9ObFm$7  
6c,]N@,Zw  
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Utility.log("Thread " + nThreadID + " is over!");  S<#>g s4  
bDownOver = true; {4J:t_<nKO  
//nPos = fileAccessI.write (b,0,nRead); Anr''J&9`H  
} 1O]'iS"  
catch(Exception e){e.printStackTrace ();} SR)G!9z_/  
} >?aPXC  
} {AUhF}
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//打印回应的头信息 0tyoH3o/d  
public void logResponseHead(HttpURLConnection con) ?f
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{ 4r&DW'  
for(int i=1;;i++) e&sZ]{uD  
{ r6S-G{o  
String header=con.getHeaderFieldKey(i); XVr>\T4  
if(header!=null) QVLv}w`O  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 
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Utility.log(header+" : "+con.getHeaderField(header)); Yef=HSzo  
else (8T36pt~  
break; `Sgj!/!F  
} "Zm**h.t  
} & mwQj<Z  
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public void splitterStop() nwuH:6~"  
{ HHVCw7r0  
bStop = true; )r2$!(NQ  
} 8T<LNC  
;w>Dqem  

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} }p,#rOX:A  
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9<0TF+}>  
/* 0<tce  
**FileAccess.java ^{Wx\+*!  
*//文件访问(定位，写) hWc`4xdl  
package NetFox; zwJB.4@  
import java.io.*; (=&z:-52V  
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public class FileAccessI implements Serializable{ F{*{f =E!B  
"#}
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 DBTeV-G9~R  
RandomAccessFile oSavedFile; OM,Dy&Y  
long nPos; h0**[LDH  
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public FileAccessI() throws IOException 5rp,xk!  
{ oKyl2jg+,  
this("",0); (h{"/sR  
}
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public FileAccessI(String sName,long nPos) throws IOException yM,.{m@F<  
{ '`s\_Q)hG_  
oSavedFile = new RandomAccessFile(sName,"rw"); *<
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this.nPos = nPos; )<ig6b%  
oSavedFile.seek(nPos); CgT5sk}
 
} _*iy *:(o  
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public synchronized int write(byte[] b,int nStart,int nLen) ,4W~CkLD  
{ pW4O[v`  
int n = -1; xWRkg$A  
try{ T-MC|>pv  
oSavedFile.write(b,nStart,nLen); FYBW3y+AF&  
n = nLen; % 9Jx|  
} >wSrllmj@  
catch(IOException e) !2=m |,  
{ GN1Q\8)o  
e.printStackTrace (); %Z
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} &VPfI  
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return n; Mo'6<"x  
} M{GT$
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} . E8Gj'yO  
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shkyN  
/* g9~QNA  
**SiteInfoBean.java >DM^/EAG{  
*/ "udA-;!@&  
package NetFox; t,w'w_C  
bU$f4J  
e^=b#!}-5:  
public class SiteInfoBean { 3g79/w  
m=[3"X3W1V  
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private String sSiteURL; //Site's URL _^ZBSx09)  
private String sFilePath; //Saved File's Path 5ho!}K  
private String sFileName; //Saved File's Name c)`=wDi  
private int nSplitter; //Count of Splited Downloading File ,7:?Du}  
ee2k..Tq#  
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public SiteInfoBean() BbIg]E/G  
{//nSplitter的缺省值为5 `; +UWdAR  
//default value of nSplitter is 5 "?AJ(>wP  
this("","","",5); fphi['X  
} 4s@oj  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 4`Ib wg6"B  
{ o? LJ,Z  
sSiteURL= sURL; `G'Z,P-a  
sFilePath = sPath; A)9F_;BY  
sFileName = sName; `g+Kv&546  
this.nSplitter = nSpiltter; rtxG-a56Q  
2F&VG|"  
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} jp+s[rRc\{  
4k_y;$4WN  
% <1&\5f<5  
public String getSSiteURL() g0-~%A,  
{ <Z j>}
 
return sSiteURL; w# R0QF  
} Oh=
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*<ILSZ  
230ijq3YG  
public void setSSiteURL(String value) i'YM9*yN  
{ +/>XOY|Ie  
sSiteURL = value; 7`J= PG$A  
} !sVW0JSh  
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public String getSFilePath() wiP )"g.t  
{ "'3QKeM1  
return sFilePath;
' e:rL.  
} $!goM~pZ  
,a34=,  
[R0E4A?M  
public void setSFilePath(String value) <4:%M  
{ q[TGEgG  
sFilePath = value; D KRF#*[=d  
} i%GNmD  
qFE(H1hy  
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public String getSFileName() 06]%$-j  
{ exxH0^  
return sFileName; F-=Xbyr3@  
} o`M.v[O  
-uei nd]  
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public void setSFileName(String value) x/L(0z  
{ Yn5a4  
sFileName = value; ;; ?OS  
} %~I%*=o[  
2l}H=DZV  
8 3Tv-X  
public int getNSplitter() r
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{ G%MdZg&i  
return nSplitter; Z8I0v$LjR  
} =rN_8&  
ih=O#f|  
3H`r|R  
public void setNSplitter(int nCount) gxc8O).5vY  
{ "ph[)/u;  
nSplitter = nCount; Ksff]##H  
} rqTsKrLe  
} IFbN ]N0  
x31Jl{x8\?  
.23Yqr'zT  
/* ?wVq5^ e  
**Utility.java YP`/dX"4  
*/ iE#I^`^V  
package NetFox; ;m~%57.;\  
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public class Utility { ~COd(,ul  
=gAn;~  
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public Utility() L=&dJpyfT  
{ 5}4>vEn  
85rjM#~
  
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} \ZtF,`Z  
?t [C?{'  
//线程睡眠 i:2eJ.  
public static void sleep(int nSecond) @r
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{ cuQAXqXC@  
try{ lnnT_[ni.  
Thread.sleep(nSecond); zU2Mno  
} M)G|K a  
catch(Exception e) &~"e["gF=  
{ RA*W Ys&xb  
e.printStackTrace (); ei!Yxw8d  
} !h70<Q^  
} ozkmZ;  
3M"eAK([  
//日志 j/, I)Za  
public static void log(String sMsg) h|N!U/(U  
{ y eWB.M~X  
System.err.println(sMsg);  zt2#6v  
} H{g&yo  
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lbm ,#  
public static void log(int sMsg) J0UF(  
{ O^r,H,3S  
System.err.println(sMsg); <K
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} b,lIndj#  
} 8F/JOtkGMt  
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2`pg0ciX (  
/* MX
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**TestMethod.java I`q"  
*/ 6]fz;\DgP  
package NetFox; .&rL>A2U  
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DS^`:^hv  
public class TestMethod { ~y>NJM>1  
mI,!8#  
:xZ^Jq91  
public TestMethod() 0[R7HX-@  
{ ///xx/weblogic60b2_win.exe w0,rFWS  
try{ ~ekV*,R"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); eVRjU  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Jj7he(!_1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Rz"
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fileFetch.start(); .Lp\Jyegs  
} Pk^W+M_)~  
catch(Exception e){e.printStackTrace ();} +&.wc;mi  
C/YjMYwKgv  
kmM->v  
} Cn.x:I@r  
:ywm4)  
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public static void main(String[] args) '\R/-.
 
{ i|CAN,'  
new TestMethod(); o,_R;'\E[a  
} fvr|<3ojo  
} sJ7ZE-v]h  
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