http断点续传简单实现（java)

/* v#a`*^ ^  
**SiteFileFetch.java WSn^P~vC  
*/ %h g=@7,|  
package NetFox; ~1`.iA  
import java.io.*; SOE#@{IXBa  
import java.net.*; <_uLf9ja  
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public class SiteFileFetch extends Thread { mG7Wu{~=U  
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SiteInfoBean siteInfoBean = null; //文件信息Bean |rH;}t|un  
long[] nStartPos; //开始位置 :t?9$ dL  
long[] nEndPos; //结束位置 -. L)-%wIV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 chQt8Ar3  
long nFileLength; //文件长度 S6h=} V)  
boolean bFirst = true; //是否第一次取文件
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boolean bStop = false; //停止标志 xM9EO(u  
File tmpFile; //文件下载的临时信息 "Fy34T0N  
DataOutputStream output; //输出到文件的输出流 >J[g)$,  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） BXO(B'1)]  
public SiteFileFetch(SiteInfoBean bean) throws IOException VE& ?Zd~  
{ Oq(_I b)9  
siteInfoBean = bean; /4YXx|V  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 24:;vcb  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [
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if(tmpFile.exists ()) =8X`QUmT  
{ v/c8P\  
bFirst = false; iH#~eg  
read_nPos(); P1vr}J  
} Vpt)?];P  
else R<Ojaj=V  
{ H;k
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nStartPos = new long[bean.getNSplitter()]; QN9$n%Z  
nEndPos = new long[bean.getNSplitter()]; l:a+o gm3  
}  LS,/EGJ  
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} 7B_;YT  
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public void run() ZO2u[HSO>  
{ *!,+%0  
//获得文件长度 i5?)E7-  
//分割文件 }pbyC  
//实例FileSplitterFetch o*:VG\#Z6  
//启动FileSplitterFetch线程 (?J6vK}S  
//等待子线程返回 ZD6rD(l9  
try{ 9U>ID{  
if(bFirst) =$}P'[V  
{ ?1xBhKq  
nFileLength = getFileSize(); N;>>HN[bBP  
if(nFileLength == -1) xrA(#\}f$  
{ q]0a8[]3  
System.err.println("File Length is not known!"); j?jEWreq]~  
} jZ7/p^c5R  
else if(nFileLength == -2) Y$--Hp4  
{ JS
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System.err.println("File is not access!"); ]cc4+}L~  
} W:aAe%S  
else BcX}[?c  
{ (s %T18  
for(int i=0;i<nStartPos.length;i++) :bE ^
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{ QBR
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); oB-&ma[ZS  
}
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for(int i=0;i<nEndPos.length-1;i++) iVd*62$@$  
{ t^Aios~F  
nEndPos = nStartPos[i+1]; U_ V0  
} #KXazZu"  
nEndPos[nEndPos.length-1] = nFileLength; mbsdiab#N  
} ^v}Z5,aN  
} j$Vv'on  
{v+i!a'+  
V3$!`T}g4  
//启动子线程 UY5ia4_D  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "}\2zub9  
for(int i=0;i<nStartPos.length;i++) DGC-`z  
{ H#E   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _R1
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H'<9;bD -  
nStartPos,nEndPos,i); Nn ?BD4i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q5BJsw  
fileSplitterFetch.start(); $.QnM  
} kNI m90,g  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 6NO=NL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ~1S7\e7{  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l'W?X '  
nEndPos = " + nFileLength); .!U `,)I  
// fileSplitterFetch[nPos.length-1].start(); BXa1[7Z  
x-nwo:OA  
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//等待子线程结束 DA]!ndJD  
//int count = 0; a,d\<mx  
//是否结束while循环 [=Np.:Y%  
boolean breakWhile = false; ,'Y*e[  
u,PrEmy-  
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while(!bStop) 8!3+Obj  
{ [dk|lkj@u\  
write_nPos(); h"l{cDk  
Utility.sleep(500); ).9-=P HlX  
breakWhile = true; 5`^"<wNI  
pP{b!1  
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for(int i=0;i<nStartPos.length;i++) *B#OLx  
{ ,PJl32  
if(!fileSplitterFetch.bDownOver) 0w< iz;30  
{ klT6?'S  
breakWhile = false; &4O"Xs`ka  
break; s<E_74q1  
} ;y=w :r\A  
} xW/JItF  
if(breakWhile) p&Nw:S  
break; ,{J2i#g<  
sFSrMI#R  
x[WT)  
//count++; |8`}yRsQ  
//if(count>4) Z'S>i*Ts  
// siteStop(); zFP}=K:o)  
} tDy1Gh/c  
x~Se-#$  
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System.err.println("文件下载结束！"); 9tl Fbu  
} BAX])~_  
catch(Exception e){e.printStackTrace ();} /RX7AXXB  
} *'d5~dz=  
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//获得文件长度 !RiPr(m@y  
public long getFileSize() 3AWB Y.  
{ p7.@ez ;  
int nFileLength = -1; ;1(OC-2>d  
try{ fQOaTsyA  
URL url = new URL(siteInfoBean.getSSiteURL()); Bw{@YDO{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); XKks j!'B  
httpConnection.setRequestProperty("User-Agent","NetFox"); H#w?$?nIWu  
f8[2
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int responseCode=httpConnection.getResponseCode(); "_?^uymw  
if(responseCode>=400) 
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{ ,wRrx&  
processErrorCode(responseCode); I62Yg p$K  
return -2; //-2 represent access is error uA}asm  
} I]I5!\\&[  
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String sHeader; v7&$(HJ>]L  
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HA  
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for(int i=1;;i++) 1$xt=*.u|  
{ jj.]R+.G  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K.X%
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//Utility.log(in.readLine()); b[*di{?-  
sHeader=httpConnection.getHeaderFieldKey(i); }jIb ^|#CD  
if(sHeader!=null) \7og&j-h  
{ (MxLw:AV  
if(sHeader.equals("Content-Length")) 7[u&%  
{ -P.) 0d(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); g2iSc  
break; (AwbZn*  
} yM\1n  
} 8,B9y
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else Nc;7KMOIA  
break; ](Sp0t  
} P!]DV$
o  
} 8,['q~z  
catch(IOException e){e.printStackTrace ();} @|d|orMC  
catch(Exception e){e.printStackTrace ();} -Tz9J4xU&  
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Utility.log(nFileLength); DOR
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return nFileLength; wz:wR+  
} =(hEr=f>7  
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kB :")$  
//保存下载信息（文件指针位置） VBd.5YW  
private void write_nPos()  ;xry  
{ (# ?~^ut  
try{ X59~)rH,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); wk-ziw  
output.writeInt(nStartPos.length); T?%F  
for(int i=0;i<nStartPos.length;i++) +  1v@L  
{ K}a[~  
// output.writeLong(nPos); .|o7YTcR
:  
output.writeLong(fileSplitterFetch.nStartPos); Y> 7/>x6  
output.writeLong(fileSplitterFetch.nEndPos); 2I#fwsb  
} 98V9AOgk  
output.close(); %tpt+N?  
} ob0clJX  
catch(IOException e){e.printStackTrace ();} f PDn
kr  
catch(Exception e){e.printStackTrace ();} *;4r|#LG  
} ZA:YoiaC#  
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67J=#%\  
//读取保存的下载信息（文件指针位置） rJg!2  
private void read_nPos() Ai/ay# E  
{ fe&K2C%bm  
try{ lRentNg0b  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >Y[{m $-  
int nCount = input.readInt(); 1UmV&  
nStartPos = new long[nCount]; o&X!75^G>  
nEndPos = new long[nCount]; kw1PIuz4&  
for(int i=0;i<nStartPos.length;i++) < FN[{YsA  
{ ! .!qJ%  
nStartPos = input.readLong(); C96|T>bk  
nEndPos = input.readLong();
<.=  
} Q=>@:1=  
input.close(); s%p(_pB  
} bBg?x 4bu  
catch(IOException e){e.printStackTrace ();} YK_a37E{F  
catch(Exception e){e.printStackTrace ();} Bz]64/  
} F"9qBl~  
:%;K`w  
*6=[Hmygi  
private void processErrorCode(int nErrorCode) cMtkdIO  
{ W;,Jte<'Nm  
System.err.println("Error Code : " + nErrorCode); KcY 2lTvx  
} jaNkWTm:  
))
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j!jZJD  
//停止文件下载 xe%+Yb]  
public void siteStop() L,\ Yj  
{ 9 ?h)U|J?G  
bStop = true; ?p6+?\H  
for(int i=0;i<nStartPos.length;i++) 8Zwq:lV Q  
fileSplitterFetch.splitterStop(); dG6Mo76  
Mi:$<fEX  
[NH[n#  
} ZW*"Kok  
} W;u~}k<  
//负责部分文件的抓取 *I>1O*  
**FileSplitterFetch.java R]L7?=  
*/ >Rx^@yQ!+z  
package NetFox; 6%O"  
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import java.io.*; ZJI|762,  
import java.net.*; V.:imj  
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public class FileSplitterFetch extends Thread { v{&cgod  
!3d+"tL S  
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String sURL; //File URL Ql#:Rx>b  
long nStartPos; //File Snippet Start Position 6 {5*9!v63  
long nEndPos; //File Snippet End Position HJoPk'p%  
int nThreadID; //Thread's ID .:$%3#N$(Y  
boolean bDownOver = false; //Downing is over /__we[$E  
boolean bStop = false; //Stop identical Q9?/)&3Bu  
FileAccessI fileAccessI = null; //File Access interface wcB-)Ra  
uFG]8pj2V1  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Hza{"I*^  
{ ZZ?=^g  
this.sURL = sURL; )2u=U9  
this.nStartPos = nStart; n16,u$|  
this.nEndPos = nEnd; z8jQaI]j  
nThreadID = id; R\1#)3e0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 f; >DM  
}
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 fW|1AUD,  
public void run() vsHY;[  
{ gmy_ZVU'  
while(nStartPos < nEndPos && !bStop) >\3=h8zw  
{ WX]kez{<uP  
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try{ gx@b|rj;  
URL url = new URL(sURL); jA<v<oV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ZrXvR`bsw  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ah)_mxK  
String sProperty = "bytes="+nStartPos+"-"; .B_)w:oF  
httpConnection.setRequestProperty("RANGE",sProperty); 3($%AGKJ  
Utility.log(sProperty); :Y~fPke  
IHMZE42  
Z/6B[,V  
InputStream input = httpConnection.getInputStream(); ;' YM@n  
//logResponseHead(httpConnection); ZGe+w](  
4E&URl0Bh  
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byte[] b = new byte[1024]; b78'yM&  
int nRead; L:%; Fx2  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) $kvF]|<bu  
{ _~| j~QE]  
nStartPos += fileAccessI.write(b,0,nRead); q2Ax-#  
//if(nThreadID == 1) a~DR$^m  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N-4LdC  
} P ;PS+S9  
0;}
 9XZ  
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Utility.log("Thread " + nThreadID + " is over!"); nW!rM($q  
bDownOver = true; |:L<Ko  
//nPos = fileAccessI.write (b,0,nRead); (,[m}Qb?!  
} v
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catch(Exception e){e.printStackTrace ();} wQlK[F]!>  
} JrQ*.lJj  
} G*3O5m  
?)'j;1_=E3  
#ZeZs31  
//打印回应的头信息 DNq=|?qn]  
public void logResponseHead(HttpURLConnection con) w<.{(1:v  
{ `oXUVr  
for(int i=1;;i++) G@BF<
e{  
{ +\?#8U
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String header=con.getHeaderFieldKey(i); .~4%TsBaY  
if(header!=null) wJ/k\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); n*{e0,gp`  
Utility.log(header+" : "+con.getHeaderField(header)); M)!8`]  
else C
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break; ,a~- (@  
} FzXVNUMP  
} ? D2:'gg  
90Jxn'>^  
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public void splitterStop() wk<QYLEk  
{ *ukE"Aj  
bStop = true; q{[}*%  
} w*eO9k  
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[Z`q7ddd^  
} *+vS f7  
/9/=]  
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/* G sm5L<rx  
**FileAccess.java =iB0ak  
*//文件访问(定位，写) f5IO<(:E^  
package NetFox; q%]0%S?  
import java.io.*; u0^GB9q  
xwW[6Ah  
N5Eb.a9S  
public class FileAccessI implements Serializable{ =P!SN]nFeP  
MW=2GhD=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vZ\~+qV,A  
RandomAccessFile oSavedFile; \SkCsE#H  
long nPos; #*:y2W%H  
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public FileAccessI() throws IOException Y.Na9&-(  
{ 9s5gi+l_O  
this("",0); L5Rj;qhi  
} X!2/cgU7  
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J GnL[9P_  
public FileAccessI(String sName,long nPos) throws IOException pP;GDW4  
{ {aqceg  
oSavedFile = new RandomAccessFile(sName,"rw"); r3<yG"J86  
this.nPos = nPos; D0/ \  
oSavedFile.seek(nPos); \/I@&$"F  
} Dtl381F J  
5 5>^H1M  
ZMQSy7  
public synchronized int write(byte[] b,int nStart,int nLen) BaIH7JLZ8  
{ :PuJF`k  
int n = -1; 'Pk ( 1:  
try{ /!rH DcR  
oSavedFile.write(b,nStart,nLen); BY.'0,H=k  
n = nLen; \b?z\bC56  
} b/5  
catch(IOException e) OWT5Bjl  
{ @{\q1J>  
e.printStackTrace (); fn>MOD!l  
} pi[:"}m]/P  
N'w;1,c+  
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return n; vG`R.  
} |f;u5r!^=  
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} q|0Lu  
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6 6WAD$8$  
/* V6
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**SiteInfoBean.java WQv%57+  
*/ &$ZJfHD@  
package NetFox; 7'uuc]\5>  
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4|\  
public class SiteInfoBean { >xb}AY;  
me"}1REa  
.I_Mmaq;i  
private String sSiteURL; //Site's URL ^3C8GzOsO  
private String sFilePath; //Saved File's Path CqOvVv  
private String sFileName; //Saved File's Name 4Ynv=G Qz  
private int nSplitter; //Count of Splited Downloading File \tH^w@j47  
musZCg$  
kBg,U8|S  
public SiteInfoBean() YMx]i,u'+  
{//nSplitter的缺省值为5 b:VCr^vp  
//default value of nSplitter is 5 w6(E$:#d  
this("","","",5); ;5QdT{$H  
} |tF:]jnIt  
#m[R1G#  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |#G.2hMFr  
{ o|FjNL  
sSiteURL= sURL; FY1 >{Bn  
sFilePath = sPath; OOJg%y*H  
sFileName = sName; ahQdB
oj  
this.nSplitter = nSpiltter; [xW;5j<87  
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} KCEBJ{jM  
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public String getSSiteURL() i
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{ RN2^=$'.  
return sSiteURL; tbMf_-g  
} zpi Q;P  
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public void setSSiteURL(String value) <!@*2/Q]J]  
{ 39Nz>Nu:
 
sSiteURL = value; oY)xXx  
} c:? tn  
rLP:kP'b  

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public String getSFilePath() `p qj~s  
{ S)`%clN}J  
return sFilePath; Y 1v9sMN,  
} haTmfh_|  
,v
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l 1C'<+2j!  
public void setSFilePath(String value)  S(*u_  
{ sn>2dRW{  
sFilePath = value; R -#40  
} ]Q8[,HTG  
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0[\sz>@  
public String getSFileName() p"l GR&b  
{ #Jx6DQGa  
return sFileName; Z|t`}lK  
} Vv|%;5(  
dUvgFOy|P  
/w|!SZB  
public void setSFileName(String value) O%Hc%EfG  
{ FqWW[Bgd  
sFileName = value; Ka4KsJN  
} s:O8dL /  
^pc?oDPSg  
'?gF9:  
public int getNSplitter() VoG_'P  
{ RA_gj lJi  
return nSplitter; #B$r|rqamq  
} ;L`NF"  
\3bT0^7B  
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public void setNSplitter(int nCount) )/:j$aq  
{ uUIjntSF(  
nSplitter = nCount; /l%+l@  
} p~A6:"8s`=  
} ~9We)FvU4  
U,g)N[|  
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/* 6Cpn::WW}  
**Utility.java "AuU5G 9'I  
*/ LlF|VR&P.  
package NetFox; j6&q6C X  
n/ CP2A  
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public class Utility { IW>\\&pJ  
XS_Ib\-50  
.-mlV ^  
public Utility() ETQL,t9m  
{ )e?6 Ncy  
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 QUb#84  
} H1or,>GoO  
+\GuZ5`  
//线程睡眠 _|C T|q  
public static void sleep(int nSecond) [ApAd  
{ EJm*L6>@R&  
try{ VthM`~3  
Thread.sleep(nSecond); f1wwx|b%.  
} J,_IHzO~Z  
catch(Exception e) )uK Tf=;  
{ btDPP k'  
e.printStackTrace (); 'iikcf*)C  
} F!MxC  
} (@3?JJ]1  
Dy|DQ>?}  
//日志 Uv|^k8(  
public static void log(String sMsg) 'Im&&uSkr  
{ mKZ^FgG  
System.err.println(sMsg); p}MH LM  
} qYbPF|Y=Z  
|W;EPQ+<  
NB.&J7v  
public static void log(int sMsg) IEQ6J}L  
{ n1@ Or=5  
System.err.println(sMsg); kT,2eel  
} 1g1gu=|Q  
} 9 :FzSD   
uTIl} N  
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/* nTH!_S>b(Y  
**TestMethod.java tRzo}_+N
 
*/ 5imqZw  
package NetFox; ghVxcK  
,}HnS)+  
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public class TestMethod { X0zE-h6P  
nk+*M9r|I  
xyaU!E*  
public TestMethod() SO}en[()O  
{ ///xx/weblogic60b2_win.exe m9li%p  
try{ HHae
rc  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #7dM %  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); JrVBd hLr  
SiteFileFetch fileFetch = new SiteFileFetch(bean); fH[:S9@  
fileFetch.start(); 0ZpWfL  
} Jm{~H%  
catch(Exception e){e.printStackTrace ();} R:FyCT_,  
*l\vqgv.Z  
liG3   
} '<KzWxuC  
K)n0?Q_>  
]J6+nA6)  
public static void main(String[] args) bmu<V1[W  
{ ,';+
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new TestMethod(); 5jBBk*/\  
} _=oNQ  
} \`:
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