http断点续传简单实现（java)

/* .22}=z  
**SiteFileFetch.java ALi
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*/ Iy;bzHXs  
package NetFox; /4>|6l=  
import java.io.*; yD yMI  
import java.net.*; t~V?p'a0ys  
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public class SiteFileFetch extends Thread { vSv:!5*  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ?WBA:?=$58  
long[] nStartPos; //开始位置 0?w
4  
long[] nEndPos; //结束位置 @$7l  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _edT+r>+  
long nFileLength; //文件长度 2#_i_j  
boolean bFirst = true; //是否第一次取文件 7Um3myXU  
boolean bStop = false; //停止标志 g{e@I;F  
File tmpFile; //文件下载的临时信息 %df[8eX{  
DataOutputStream output; //输出到文件的输出流 #9/S2m2\YG  
#XeEpdE  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） F*_ytL  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7hAc6M$h;  
{ 1#V&'A  
siteInfoBean = bean; oTb4T=  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); f-5}`)`.+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); K!O7q~s[D  
if(tmpFile.exists ()) !{S HlS  
{ 'fka?lL  
bFirst = false; *n*po.Xr  
read_nPos(); 5 8n(fdE  
} !glGW[r/7  
else xG8z4Yu   
{ w1,6%?p(O  
nStartPos = new long[bean.getNSplitter()]; ?UBhM,;XK  
nEndPos = new long[bean.getNSplitter()]; fctVJ{?  
} _xdFQ  
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} l.%[s6  
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public void run() ]-8yZWal  
{ /rzZU}3[  
//获得文件长度 pVC;''E  
//分割文件 sSsRn*LN-:  
//实例FileSplitterFetch T?EFY}
f  
//启动FileSplitterFetch线程 9~6~[z  
//等待子线程返回 i3<ZFR  
try{ m:C|R-IL  
if(bFirst) ^ jT1q_0  
{ GU]_Z!3  
nFileLength = getFileSize(); mAuN* (  
if(nFileLength == -1) ct@i]}"`  
{ 0
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System.err.println("File Length is not known!"); Ir$:e*E>  
} a{4RG(I_  
else if(nFileLength == -2) y R_x:,|g  
{ l
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System.err.println("File is not access!"); la*c/*  
} (nt=  
else !~a1xI~s  
{ {f[X)  
for(int i=0;i<nStartPos.length;i++) S1E=EVG  
{ $LJCup,1"  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); b:YyzOqEu  
} #RVN7-x  
for(int i=0;i<nEndPos.length-1;i++) vF.Ml  
{ .Eg[[K_iD  
nEndPos = nStartPos[i+1]; "V:E BR  
} 1ZRSeh  
nEndPos[nEndPos.length-1] = nFileLength; "Rq)%o$Z  
} {U7A&e0eW  
} tN&_f==e  
&?#!%Ds  
Fa9gr/.F,@  
//启动子线程 |<w Z;d  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {+x;J4  
for(int i=0;i<nStartPos.length;i++) tjt#2i8/  
{ F'3-*>]P  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ca?;!~%zA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), x[1(cj  
nStartPos,nEndPos,i); BZs?tbf  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); PtT$#>hx]  
fileSplitterFetch.start(); )d"s6i
 
} Vv~:^6il  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @Yzc?+x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :yE7jXB  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", pb=yQ}.  
nEndPos = " + nFileLength); MP%pEUomev  
// fileSplitterFetch[nPos.length-1].start(); V8IEfU  
Q0-}!5`E1$  
sA[eKQjaD  
//等待子线程结束 e2*Fe9:  
//int count = 0; Bw8&Amxx:  
//是否结束while循环 WJ m:?,  
boolean breakWhile = false; OE_>Kw7q  
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while(!bStop) B4ky%gF4  
{ -40OS=wpA  
write_nPos(); -8D$[@y(  
Utility.sleep(500); z!/ MBM  
breakWhile = true; h;Se.{  
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for(int i=0;i<nStartPos.length;i++) ,`;D
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{ HzD=F
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if(!fileSplitterFetch.bDownOver) ~@N0$S  
{ RlnJl
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breakWhile = false; .qG*$W2f  
break; /{+77{#Qn  
} nN[gAM (  
} fk  
if(breakWhile) iJem9XXb  
break; oar`xH$C  
=EdLffU[J  
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//count++; /8tF7Mmr  
//if(count>4) `Wy8g?d;bn  
// siteStop(); Tv`-h  
} kr6^6
I.  
+oe%bk|A  
_ ZC[h~9H  
System.err.println("文件下载结束！"); a~"<lzu|$  
} P1Chmg  
catch(Exception e){e.printStackTrace ();} SVc5mS|up  
} {ehAF=C  
TWk1`1|  
^VAvQ(b!:i  
//获得文件长度 gyAKjLqqpi  
public long getFileSize() FQGh+.U  
{ ]eD5It\  
int nFileLength = -1; L#X!.  
try{ Ij}k>qO/2  
URL url = new URL(siteInfoBean.getSSiteURL()); +/Q?<*[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1E|~;wo\  
httpConnection.setRequestProperty("User-Agent","NetFox"); rP7~R  
! fSM6Vo  
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int responseCode=httpConnection.getResponseCode(); {'R\C5:D7  
if(responseCode>=400) OJ Y_u[  
{ Lr}>Md  
processErrorCode(responseCode); xBW{Wy
h  
return -2; //-2 represent access is error [!CIBK99  
} ZJeTx.Gi6  
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.P>-Fh,_p  
String sHeader; 1xF<c<  
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for(int i=1;;i++) q*B(ZG  
{ GVt}\e~"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); g4fe(.?c,  
//Utility.log(in.readLine()); Z_Z; g]|!  
sHeader=httpConnection.getHeaderFieldKey(i); T6=q[LpsKN  
if(sHeader!=null) %HK\  
{ eFiUB  
if(sHeader.equals("Content-Length")) &@anv.D  
{ ?E88y  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _6,Tb]  
break; gNoQ[xFx32  
} F"*.Qq  
} i9%cpPrg8  
else fR6.:7&  
break; %juR6zB%8  
} XK7$Xbd  
} j/+e5.EX/  
catch(IOException e){e.printStackTrace ();} @g~hYc  
catch(Exception e){e.printStackTrace ();} c5e wG  
;[>g(W+  
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Utility.log(nFileLength); J&bhR9sF  
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return nFileLength; d#*n@@V4  
} = rLL5<  
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//保存下载信息（文件指针位置） 4`Z8EV  
private void write_nPos() _RcFV  
{ C
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try{ bn8`$FA^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); '&#YaD=""  
output.writeInt(nStartPos.length); |#6))Dh  
for(int i=0;i<nStartPos.length;i++) g.re`m|Aj  
{ w2/3\3p  
// output.writeLong(nPos); ^&mJDR
e  
output.writeLong(fileSplitterFetch.nStartPos); 0Zq jq0O#  
output.writeLong(fileSplitterFetch.nEndPos); #^FDFl  
} ILQB%0!  
output.close(); ozr82  
} |`50Tf\J  
catch(IOException e){e.printStackTrace ();} u^!c:RfE?  
catch(Exception e){e.printStackTrace ();} ZC\&n4~7  
} k-uwK-B}v+  
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o :tz_5  
//读取保存的下载信息（文件指针位置） M((]> *g  
private void read_nPos() }#h>*+Q  
{ h*JzJ0X  
try{ NLLLt  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O5:2B\B  
int nCount = input.readInt(); 2UF ,W]  
nStartPos = new long[nCount]; }j. [h;C6  
nEndPos = new long[nCount]; #~Z55D_  
for(int i=0;i<nStartPos.length;i++) !y{t}|U/d  
{ =gjq@N]lAW  
nStartPos = input.readLong(); aN/0'V|&ym  
nEndPos = input.readLong(); z:_o3W.E  
} U=a'(fX  
input.close(); g;Lk 'Ky6  
} j$z<
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catch(IOException e){e.printStackTrace ();} '.mHx#?7  
catch(Exception e){e.printStackTrace ();} 0;bi*2U  
} RTgR>qI&)  
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[  
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private void processErrorCode(int nErrorCode) =h<LlI^v  
{ ?pAO?5Z:}  
System.err.println("Error Code : " + nErrorCode); Vif0z*\e{  
} !k= ~5)x  
TL?(0]Hfe  
2unaK<1s  
//停止文件下载 #
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public void siteStop() dD Zds k+!  
{ z+Cw*v\Y  
bStop = true;  d Xiv8B1  
for(int i=0;i<nStartPos.length;i++) xp4w9.X5(  
fileSplitterFetch.splitterStop(); >O:31Uk  
}95;qyQ$  
\ M_}V[1+  
} F;Lg w^1!  
} 1gTW*vLM\  
//负责部分文件的抓取 ,>^6ztM  
**FileSplitterFetch.java aNLkkkJg<;  
*/ >pVrY; P[  
package NetFox; opKk#40  
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import java.io.*; &3nbmkM  
import java.net.*; 6Wm`Vj(s  
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public class FileSplitterFetch extends Thread { },d`<^~  
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.5;Xd?  
String sURL; //File URL nS53mLU)  
long nStartPos; //File Snippet Start Position *,UD&N_)*6  
long nEndPos; //File Snippet End Position i"h '^6M1  
int nThreadID; //Thread's ID ,1s,G]%M  
boolean bDownOver = false; //Downing is over Gxtb@`f  
boolean bStop = false; //Stop identical 4a&*?=GG  
FileAccessI fileAccessI = null; //File Access interface TaZw_)4c  
XYOPX>$T  
|9;6Cp  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,EAf/2C  
{ /-.i=o]b  
this.sURL = sURL; &@c?5Ie5  
this.nStartPos = nStart; 4r&S&^  
this.nEndPos = nEnd; KVvzVQ1  
nThreadID = id; cNX0.7Ls  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [^cflmV  
} d=TZaVL$$  
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7.r}98V  
public void run() ]$StbBP  
{ cPemrNxydN  
while(nStartPos < nEndPos && !bStop) <HLe,  
{ *6-fvqCv  
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try{ abHW[VP9  
URL url = new URL(sURL); Vu%XoI)<KY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vBMuVpzO  
httpConnection.setRequestProperty("User-Agent","NetFox"); $ylQ \Y'  
String sProperty = "bytes="+nStartPos+"-"; \G3P[
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httpConnection.setRequestProperty("RANGE",sProperty); *q?-M"K  
Utility.log(sProperty); HywT  
n>_EEw2/  
<*g!R!  
InputStream input = httpConnection.getInputStream(); b;N[_2  
//logResponseHead(httpConnection); 3c"$@W:>  
g=*`6@_=  
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byte[] b = new byte[1024]; =?*6lS}gy  
int nRead; A?Dg
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &nc0stuL  
{ urlwn*!^s  
nStartPos += fileAccessI.write(b,0,nRead); (|6Y1``  
//if(nThreadID == 1) p m4g),s  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v{N4*P.0T  
} $Vi[195]2  
T,Bu5:@#  
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Utility.log("Thread " + nThreadID + " is over!"); [|=#~(yYQ  
bDownOver = true;
-`iXAyr)m  
//nPos = fileAccessI.write (b,0,nRead); Y7vTs
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}  Nn"[GB  
catch(Exception e){e.printStackTrace ();} ,~R`@5+  
} BVKr
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} "5KJ /7q!  
>y2;sJ4]D%  
wH=L+bA>a  
//打印回应的头信息 CO
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public void logResponseHead(HttpURLConnection con) +s*OZ6i [  
{ D^?jLfW8  
for(int i=1;;i++) M  `QYrH  
{ cB;:}Q08#  
String header=con.getHeaderFieldKey(i); D# $Fj  
if(header!=null) +h64idM{U  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 14[+PoF^A  
Utility.log(header+" : "+con.getHeaderField(header)); h6*&1r  
else `A]CdgA  
break; fZ9EE3  
} yj^LX2x"  
} -xJ_5  
19Cs 3B\4  
(RDY-~#~  
public void splitterStop() B8jSdlvz  
{ |Ef\B]Ns  
bStop = true; n21Pfig  
} s`j QX\{  
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4Y):d!'b  
} W"m\|x  
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;XJK*QDN  
/* r'kUU]j9  
**FileAccess.java cTA8F"UGD  
*//文件访问(定位，写) n{>Ge,enP0  
package NetFox; D 8nt%vy  
import java.io.*; .6,+q2tyk,  
(xp<@-  
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public class FileAccessI implements Serializable{ b`NXe7A  
kOe%w-_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >&@hm4  
RandomAccessFile oSavedFile; `1cGb*b/  
long nPos; z (N3oBW  
QT1(= wK3  

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public FileAccessI() throws IOException 1v)X]nW  
{ !]%M  
this("",0); tSST.o3  
} C~do*rnM^  
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public FileAccessI(String sName,long nPos) throws IOException e&Z\hZBb  
{ $/\b`ID  
oSavedFile = new RandomAccessFile(sName,"rw"); T ;Ga G  
this.nPos = nPos; NDw+bR-  
oSavedFile.seek(nPos); 59?@55  
} 4?#0fK  
u!k]Q#2ZR  
<b-BJ2],k  
public synchronized int write(byte[] b,int nStart,int nLen) ;2o+|U@  
{ pK)*{fC$`  
int n = -1; p^2"g~  
try{ i\P?Y(-{  
oSavedFile.write(b,nStart,nLen); -
nWs@\  
n = nLen; :NB,Dz+i  
} 8+m[ %5lu  
catch(IOException e) Qfhhceb6#J  
{ U=?hT&w\S  
e.printStackTrace (); UbBo#(TZ)  
} R&z)  
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)+^1QL  
return n; omxBd#;F$  
} T&?0hSYt  
z|Z<S+=f  
#n=b*.  
} kzA%.bP|  
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< q6z$c)K  
/*  b>N)H  
**SiteInfoBean.java o8!gV/oy  
*/ QN%w\JXS  
package NetFox; ?/mkFDN  
*.
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public class SiteInfoBean { O1/U3/2/d  
DVu_KT[Hd  
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private String sSiteURL; //Site's URL !B=Oc!e=K  
private String sFilePath; //Saved File's Path ;WQ@dC  
private String sFileName; //Saved File's Name O|#N$a&_N  
private int nSplitter; //Count of Splited Downloading File t@GPB]3[  
A#s`!SNv  
8\-Q(9q(  
public SiteInfoBean() IAr  
{//nSplitter的缺省值为5 HaP0;9q  
//default value of nSplitter is 5 eqt+EiH   
this("","","",5); :n3)vK   
} 8S&Kf>D  
KRS_6G],{  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >*xa\ve  
{ }*!7 Vrep  
sSiteURL= sURL;
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sFilePath = sPath; b8V]/  
sFileName = sName; 2.I'`A  
this.nSplitter = nSpiltter; -+1it  
^*7~ Wxk5  
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} ;T0Y=yC  
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1a#oJU  
public String getSSiteURL()
={9G.%W  
{ K)2ZH@  
return sSiteURL; <B]\&  
} ^}XKhn.S'  
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_VU/j9<+  
public void setSSiteURL(String value) {~g(W
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{ ;!<WL@C~  
sSiteURL = value; im&E\`L7  
} 8uyUvSB  
&tFVW[(  
{mPaloA  
public String getSFilePath() C24[brf  
{ -GkNA"2M[  
return sFilePath; 7@g8nv(p  
} ^/K\a ,  
t&UPU&tY  
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public void setSFilePath(String value) NiU}A$U  
{ e";r_J3w  
sFilePath = value; _W41
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} 0N3 cC4!  
s8| =1{  
6JWCB9$4  
public String getSFileName() ;dl>  
{ ZF :e6em  
return sFileName; @;}bBHQz{p  
} hd~X c  
YmM+x=G:  

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public void setSFileName(String value) )rv5QH`i  
{ 7<[p1C*B  
sFileName = value; o+W5xHe^1  
} ]=p@1  
'iO?M'0gE#  
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public int getNSplitter() G#/}
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{ $ WAFr  
return nSplitter; 8P r H"pI  
} @NGK2J  
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public void setNSplitter(int nCount) q10gKVJum  
{ W=M`Bkw{  
nSplitter = nCount; THirh6  
} b:.aZ7+4  
} P0J3ci}^  
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l  
/* I0 a,mO;m  
**Utility.java v8"plx=3  
*/ \P]w^  
package NetFox; >ir'v5  
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public class Utility { @'U9*:}U  
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)  
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public Utility() vCT5do"C&  
{ fk)ts,p?  
?Y2ZqI  
~vnG^y>%  
} e2Sm.H '  
5k.NZ  
//线程睡眠 eRQ}`DjTk  
public static void sleep(int nSecond) 7 Xe|P1@)  
{ z]ZhvH7-  
try{ vlth\[  
Thread.sleep(nSecond); x\r7q  
} 9^h\vR|]S  
catch(Exception e) mD-qJ6AM  
{ <`*}$Zh  
e.printStackTrace (); Pk[:+. f(  
} vJDK]p<}  
} obRR))  
U>6MT@\  
//日志 !)RND 6.  
public static void log(String sMsg) 2yR*<yj  
{ +8 5]]}I  
System.err.println(sMsg); X-9>;Mb~y  
} N-|E^XIV  
Et
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*@=in7*c  
public static void log(int sMsg) Mk"+*G  
{ Z`nHpmNM  
System.err.println(sMsg); 5R}Qp<D[^  
} -4`Wkkhu  
} LY2oBX@fC  
|;_NCy8i3X  
%se4aeOrX  
/* 1VK?Svnd  
**TestMethod.java <qN0Q7  
*/ T!5m'Q.  
package NetFox; /kE3V`es  
9@ [R>C  
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public class TestMethod { Ql a'vcT  
j*>+^g\Q6  
3}=r.\]U  
public TestMethod() :S}!i?n  
{ ///xx/weblogic60b2_win.exe ~C=I{qzF+  
try{ 1C\OL!@L  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); .MkHB0 2N  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M3@Wb@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \UM9cAX`  
fileFetch.start(); ^]w!ow41  
} y:(OZ%g  
catch(Exception e){e.printStackTrace ();} IY6DZP  
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,80qwN,  
} \"B?'Ep;  
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D].!u{##  
public static void main(String[] args) u Jy1vI  
{ YO7Y1(`  
new TestMethod(); Wr Ht  
} Nq1la8oQ3  
} }#'wy  
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