http断点续传简单实现（java)

/* W>
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**SiteFileFetch.java T5S4,.o9W  
*/ Yj%]|E-  
package NetFox; a.Ho>(V/4  
import java.io.*; ^*K=wE}AG  
import java.net.*; ]&cnc8tC  
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public class SiteFileFetch extends Thread { 1Kg0y71"  
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SiteInfoBean siteInfoBean = null; //文件信息Bean L, JQ\!c  
long[] nStartPos; //开始位置 ?'
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long[] nEndPos; //结束位置 JMb_00r  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 dftBD  
long nFileLength; //文件长度 s]arNaaA  
boolean bFirst = true; //是否第一次取文件 x:Y9z_)O  
boolean bStop = false; //停止标志 ;G[V:.o-  
File tmpFile; //文件下载的临时信息 22g
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DataOutputStream output; //输出到文件的输出流 j[>cv;h ;  
{/'T:n
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） y0zMK4b  
public SiteFileFetch(SiteInfoBean bean) throws IOException +P/kfY"  
{ wP!X)p\  
siteInfoBean = bean; p3Sh%=HE'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); A#{63_H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); bsIG1&n'T  
if(tmpFile.exists ()) IhnBp 6p9  
{ p_FM 2K7!  
bFirst = false; nhV"V`|d  
read_nPos(); wQ}r/2n|^  
} RBX<>*  
else #[93$)Gd!  
{ IGlR,tw_/  
nStartPos = new long[bean.getNSplitter()]; i5,iJe0cA  
nEndPos = new long[bean.getNSplitter()]; ).T&fa"  
} >=~\b  
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} S@qp_!  
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public void run() 0RUk^  
{ 6Rc=!_v^  
//获得文件长度 Knq9"k  
//分割文件 i?00!t  
//实例FileSplitterFetch / f%mYL  
//启动FileSplitterFetch线程 yI0bSu<j-  
//等待子线程返回 K
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try{ _(W@FS  
if(bFirst) Dg&84,bv^  
{ #6`5-5Ks;  
nFileLength = getFileSize(); P3M$&::D-  
if(nFileLength == -1) Fn4v/)*H  
{ 04a ^jjc  
System.err.println("File Length is not known!"); f5jl$H.  
} JF~i.+{h  
else if(nFileLength == -2) u-_r2U  
{ Gp"GTPT{  
System.err.println("File is not access!"); ?J}Q&p.  
} c_lHj#A(l  
else )>volP  
{
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for(int i=0;i<nStartPos.length;i++) v4$/LUJZp  
{ UKS5{"=T[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #c"eff  
} l
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for(int i=0;i<nEndPos.length-1;i++) mU'<:gL+  
{ m[hL GD'Fi  
nEndPos = nStartPos[i+1]; %!aU{E|@_  
} lu8G$EQI  
nEndPos[nEndPos.length-1] = nFileLength; rfXxg^  
} 12$0-@U  
} >)><u4}  
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1{}p_"s>  
//启动子线程 JA^o/%a^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^X#y'odtbS  
for(int i=0;i<nStartPos.length;i++) ] V D  
{ +v~xgUs  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ! 'zd(kv<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), T$Z9F^w  
nStartPos,nEndPos,i); TpjiKM  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); y^.66
BH  
fileSplitterFetch.start(); *}[\%u$ T  
} }Zhe%M=}G  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RLF&-[mr3  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); x4_
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", qJey&_  
nEndPos = " + nFileLength); }@DCcf$<  
// fileSplitterFetch[nPos.length-1].start(); v.0qE}' |  
MKK ^-T  
((y|?Z$  
//等待子线程结束 kA:Y^2X'  
//int count = 0; Fs+tcr/\[  
//是否结束while循环 O zAIz+`  
boolean breakWhile = false; @W,jy$U  
/l$x}  
BK$y>= `  
while(!bStop) yR}.Xq/  
{ {U4!sJSl1  
write_nPos(); /dnwN7Gf  
Utility.sleep(500); `e[S Zj\  
breakWhile = true; Q>niJ'7WF  
i'tMpS3  
!MbzFs~  
for(int i=0;i<nStartPos.length;i++) [%W'd9`>  
{ Ufr@j` *  
if(!fileSplitterFetch.bDownOver) ^r}c&@  
{ ?R`S-  
breakWhile = false; ggso9ZlLu+  
break; WBe0^=x  
} FO{=^I5YA  
} 1 ZdB6U0  
if(breakWhile) PKm|?kn{0(  
break; $l.*;h*  
r )|3MUj  
l#)X/(?;  
//count++; cNll??j  
//if(count>4) `oRyw6Sko  
// siteStop(); h~dQ5%  
} )p&g!qA  
{Jr1K,  
`Rq=:6U;3  
System.err.println("文件下载结束！"); 8|&,JdT  
} qGk+4 yC  
catch(Exception e){e.printStackTrace ();} R2bqhSlF  
} Im]@#X  
]8G 'R-8}  
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//获得文件长度 K#"=*p,  
public long getFileSize() u@a){A(P  
{ _H]\  
int nFileLength = -1; @T1G#[C~t  
try{ "Ih3  
URL url = new URL(siteInfoBean.getSSiteURL()); UpoSC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -@Ap;,=  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y,]Lk<Hm3  
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int responseCode=httpConnection.getResponseCode(); ?0qVyK_
1  
if(responseCode>=400) xC76jE4  
{ 0TN28:hcD  
processErrorCode(responseCode); (P>nA3:UXB  
return -2; //-2 represent access is error *,u3Wm|7  
} cXweg;  
,05PYBc3  
"1o{mvCkR  
String sHeader; 7lC$UQx8  
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for(int i=1;;i++) Ku5||u.F4*  
{ X'A`"}=_  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Bwg(f_[1  
//Utility.log(in.readLine()); uHbg&eW  
sHeader=httpConnection.getHeaderFieldKey(i); ixTjXl2g  
if(sHeader!=null) jCd]ENl+_  
{ VFE@qX|  
if(sHeader.equals("Content-Length")) |3$Ew.  
{ J+D|/^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); "O$bq::(]e  
break; l5z//E}W  
} _{|a<Keq|  
} W]4Z4&  
else zDFNx:h  
break; +%5L2/n7  
} rzY)vC+ZT  
} aIgexi,  
catch(IOException e){e.printStackTrace ();} KpN]9d   
catch(Exception e){e.printStackTrace ();} XG#?fr}L  
+'F;\E  
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Utility.log(nFileLength); Lg4|6.Ez|P  
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5:PS74/  
return nFileLength; ?XKX&ws  
} p.:651b  
g{&5a(W&`  
*qpFtBg  
//保存下载信息（文件指针位置） SQMl5d1d:  
private void write_nPos() rgy I:
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{  bPsvoG  
try{ <ZT C^=3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); eP~bl   
output.writeInt(nStartPos.length); wd:Yy  
for(int i=0;i<nStartPos.length;i++)  9qX$  
{ h!tpi`8\z  
// output.writeLong(nPos); 2EgvS!"  
output.writeLong(fileSplitterFetch.nStartPos); @@R Mm$  
output.writeLong(fileSplitterFetch.nEndPos); 4U2{1aN`  
} lpT&v;$`  
output.close(); Y9BQLu4F  
} 8W3zrnc  
catch(IOException e){e.printStackTrace ();} k(H&Af+  
catch(Exception e){e.printStackTrace ();} AKk=XAGW  
} b'wy{~l@  
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"{<X! ^u>  
//读取保存的下载信息（文件指针位置） Mi]^wCF  
private void read_nPos() $(}rTm  
{ K6{wM  
try{ #1dVp!?3T  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); bvD}N<>3N  
int nCount = input.readInt(); Z+B*V)a=  
nStartPos = new long[nCount]; |s3;`Nxu7  
nEndPos = new long[nCount]; m|NZ093d  
for(int i=0;i<nStartPos.length;i++) coCT]<  
{ Kp7DI0~  
nStartPos = input.readLong(); Jp jHbG  
nEndPos = input.readLong(); L|1,/h 8p  
} [aSuEu?mC  
input.close(); @x `X|>&  
} y;o - @]  
catch(IOException e){e.printStackTrace ();} 2ZxhV4\  
catch(Exception e){e.printStackTrace ();} ^%!{qAp}Z  
} l]G iz&  
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#WjQ'c:  
private void processErrorCode(int nErrorCode) 5V 2ZAYV  
{ T]wC?gQG  
System.err.println("Error Code : " + nErrorCode); l/k-`LeW  
}
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DE.].FD
'  
//停止文件下载 R;HE{q[ f  
public void siteStop() v4e4,Nt  
{ 3$hIc)  
bStop = true; s.4+5
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for(int i=0;i<nStartPos.length;i++) E6 oC^,ZRy  
fileSplitterFetch.splitterStop(); `E|i
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} Kyx9_2  
} fXWy9 #M  
//负责部分文件的抓取 %NQ mV_1  
**FileSplitterFetch.java k'r}@-X  
*/ yeyDB>#Va.  
package NetFox; {.Qv1oOa  
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import java.io.*; `h'+4  
import java.net.*; 0n:cmML)D  
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public class FileSplitterFetch extends Thread { YPx+9^)  
4AN8Sx(  
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String sURL; //File URL KBM*7raA  
long nStartPos; //File Snippet Start Position N3$1f$`  
long nEndPos; //File Snippet End Position 3li$)S1z  
int nThreadID; //Thread's ID CUJq [  
boolean bDownOver = false; //Downing is over % PzkVs  
boolean bStop = false; //Stop identical Z*M
{  
FileAccessI fileAccessI = null; //File Access interface Jqb~RP~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException A6[FH\f  
{ gcnX^[`S  
this.sURL = sURL; * WV=Xp  
this.nStartPos = nStart; .xqi7vVHZ  
this.nEndPos = nEnd; nA0%M1a  
nThreadID = id; .@fA_8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 mrr]{K  
} %|JiFDjp  
W,EIBgR(R5  
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public void run() ?j8!3NCl}  
{ 7j)ky2r#  
while(nStartPos < nEndPos && !bStop) GXxI=,L8F  
{ ~~Bks{"BS  
cFc(HADM`r  
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try{  <O7!(  
URL url = new URL(sURL); S'5)K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /e"iYF  
httpConnection.setRequestProperty("User-Agent","NetFox"); WzstO}?P(  
String sProperty = "bytes="+nStartPos+"-"; inh:b .,B  
httpConnection.setRequestProperty("RANGE",sProperty); TC-Vzk G|  
Utility.log(sProperty); qkKl;Z?Y:  
;N#}3lpLqg  
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InputStream input = httpConnection.getInputStream(); |\dv$`_T  
//logResponseHead(httpConnection); -$"$r ~ad  
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byte[] b = new byte[1024]; _cvX$(Sg  
int nRead; /?r A|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <Q(E {c3"  
{ Q>D//_TF  
nStartPos += fileAccessI.write(b,0,nRead);  >SQzE
 
//if(nThreadID == 1) "a].v 8l!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N ;=zo-8  
} Y_Fn)(  
%SB4_ r*<  
/pjl6dJ t  
Utility.log("Thread " + nThreadID + " is over!"); "LTw;& y  
bDownOver = true; A:ts_*  
//nPos = fileAccessI.write (b,0,nRead); =s!0EwDH3  
} Mv%Qze,\V^  
catch(Exception e){e.printStackTrace ();} zc8^#D2y&  
} vY
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} 9HO9>^
 
{[#)Q.2  
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//打印回应的头信息 ;U>nj],uv  
public void logResponseHead(HttpURLConnection con) IQU1 JVkZ  
{ @]q^OMLY  
for(int i=1;;i++) Bc.de&Bxz_  
{ K?J_cnJ`  
String header=con.getHeaderFieldKey(i); ,z.l#hj,{  
if(header!=null) 2Snb+,o2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); KO=$Hr?f;  
Utility.log(header+" : "+con.getHeaderField(header)); G+N1#0,q  
else 1iY4|j;ahV  
break; )1!<<;@0  
} lS9S7`  
} @=l6zd@  
~(v5p"]dj  
a%.W9=h=M(  
public void splitterStop() 0e<>2AL   
{ %d];h  
bStop = true; <[\I`kzq  
} keLeD1  
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}?,YE5~  
} #M|lBYdW}  
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/* iS,l  
**FileAccess.java 0F-{YQr>  
*//文件访问(定位，写) =s":Mx,o  
package NetFox; rlR!Tc>  
import java.io.*; Fc@R,9  
5c3-?u!  
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public class FileAccessI implements Serializable{ 3as=EYm  
d eT<)'"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 "\EX)u9ze  
RandomAccessFile oSavedFile; Xi%Og
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long nPos; i*/i"W<  
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[-*&ZYp  
public FileAccessI() throws IOException d^A]]Xg  
{ T='uqKW\  
this("",0); 4*qBu}(  
} ]O@iT= *3  
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}},0#Ap
 
public FileAccessI(String sName,long nPos) throws IOException _M/N_Fm  
{ #?w07/~L  
oSavedFile = new RandomAccessFile(sName,"rw"); I+H~ 5zq.  
this.nPos = nPos; %4m Nk}tyH  
oSavedFile.seek(nPos); g8uqW1E^  
} =oI[E~1<  
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0]bt}rh  
public synchronized int write(byte[] b,int nStart,int nLen) fY9+m}$S$  
{ SPE)db3  
int n = -1; v^@)&,  
try{
H9)n<r  
oSavedFile.write(b,nStart,nLen); Is4,QnY_[  
n = nLen; 86)2\uan  
} `;Tf_6c  
catch(IOException e) ywJ [WfCY  
{ #epbc K  
e.printStackTrace (); g6%]uCFB  
} Mu>
  
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#4mRMsW5"  
return n; 3h:~NL  
} jzV"(p!  
73rme,  
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} lo>9 \ Po  
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/* b_RO%L:"yL  
**SiteInfoBean.java `B@eeXa;u  
*/ 5NZuaN  
package NetFox; ]0*aE  
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public class SiteInfoBean { `hO%(9V9  
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l  
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private String sSiteURL; //Site's URL A#cFO)"  
private String sFilePath; //Saved File's Path i'li;xUhZ  
private String sFileName; //Saved File's Name k)-+ZmMOh  
private int nSplitter; //Count of Splited Downloading File %TQ4ZFD3  
|p[Mp:^^  
&Tt7VYJfIV  
public SiteInfoBean() -+@N/d5  
{//nSplitter的缺省值为5 n#x_da-m]  
//default value of nSplitter is 5 ]%D!-[C%1  
this("","","",5); Pv5S k8  
} F%-@_IsG#  
`f}s<At  
z)hK2JD  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8%CznAO"?W  
{ 68,j~e3-i  
sSiteURL= sURL; ,WWd%DF)  
sFilePath = sPath; }{N#JTmjB#  
sFileName = sName; tcj"rV{G  
this.nSplitter = nSpiltter; =h4uN,  
IW
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"<0!S~]  
} +h"i6`g  
"qq$i35x  
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public String getSSiteURL() &D M3/^70  
{ +:@^nPfHy  
return sSiteURL; P?
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} =F_uK7W  
s?}qi
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5z0Sns  
public void setSSiteURL(String value) A^,ul>!  
{ ,JdBVt  
sSiteURL = value; XA#qBxp/h  
} Xw9]WJc  
]2m=lt1  
NW6;7nWb  
public String getSFilePath() gS<p~LPf  
{ tRU/[?!  
return sFilePath; >97YK =  
} CbM~\6R  
NOs00H  
?MFC(Wsh  
public void setSFilePath(String value) C'[4jz0xF  
{ {2q"9Ox"  
sFilePath = value; [!%5(Ro_  
} t`Bk2Cc)+  
} 9zi5o8  
o=Z:0Ukl]  
public String getSFileName() *Hn=)q  
{ zqj|$YNC  
return sFileName; Fxa{ 9
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} ,|RKM  
i}8OaX3x  
(.N n|lY<i  
public void setSFileName(String value) 12#yHsk  
{ @lDnD%vZ`  
sFileName = value; n>u_>2Ikkj  
} 9<rs3 84  
]vf_4QW=  
OSO
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public int getNSplitter() m&=Dy5  
{ Rp2h[_>
 
return nSplitter; GjwH C{  
} $MDmY4\  
GCYXDovh  
|e#W;q$v  
public void setNSplitter(int nCount) eMdP4<u  
{ Os[z>H?  
nSplitter = nCount; m<j;f  
} ^E/6vG  
} OH>Gc-V  
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.^A4w;jPU  
/* D,..gsg  
**Utility.java [gUD +  
*/ rOLZiET  
package NetFox; r(wf>w3  
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4
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public class Utility { )kjQ W&)g  
bJPKe]spJ=  
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public Utility() kO`!!M[Oo  
{ x_O:IK.>  
92Gfxld\  
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} -,*m\Fe}  
a=ZVKb  
//线程睡眠 =k d
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public static void sleep(int nSecond) pFd{Tdh  
{ 91R7Rrne  
try{ .7 j#F  
Thread.sleep(nSecond); ABoB=0.l  
} nt_Cb*K<  
catch(Exception e) K+/wJ9^B  
{ Ge=6l0  
e.printStackTrace (); U4dfO=  
} *?Wz/OJ0  
} ~h<T0Zc  
p/0dtnXa(  
//日志 sE]z.Po=  
public static void log(String sMsg) N68]r3/K  
{ V1Ft3Msq  
System.err.println(sMsg); hy#nK:B  
} MA9E??p3\  
+(Hp ".gU  
JO]?u(m01  
public static void log(int sMsg) vt"bB  
{ bO$KV"*!  
System.err.println(sMsg); xH28\]F5n  
} <J~6Q  
} XjzGtZ#6  
g3'dkS!  
PfYeV/M|  
/* ]4c*Nh%8  
**TestMethod.java "MzBy)4Q  
*/ H;a) `R3  
package NetFox; D dwFKc&  
*>aVU'  
@ukL!AV?Y  
public class TestMethod { IV1O/lGp
 
'%e@7Cs  
g}6M+QNj  
public TestMethod() |2TH[J_a  
{ ///xx/weblogic60b2_win.exe N49{J~  
try{ KJ&I4CU]^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); j-aTpN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,*V%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >G?*rg4  
fileFetch.start(); .0/"~5  
}  \v:Z;EbX  
catch(Exception e){e.printStackTrace ();} k=d_{2 ~  
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/w6'tut  
} $&, KZ>  
<a
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, DuyPBAms  
public static void main(String[] args) W4qT]m  
{ F{ 4k2Izr  
new TestMethod(); `\z )EoI  
} ~|~2B$JeV  
} lGT[6S\as  
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