http断点续传简单实现（java)

/* piIZ*@'  
**SiteFileFetch.java Q}#4Qz~n  
*/ 8%4;'[UV  
package NetFox; Y58H.P  
import java.io.*; ZfM]A)  
import java.net.*; e.\>GwM  
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public class SiteFileFetch extends Thread { 5N9Cd[4  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Hc/7x).  
long[] nStartPos; //开始位置 e`Yj}i*bx]  
long[] nEndPos; //结束位置 su0K#*P&I  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 za>%hZf\  
long nFileLength; //文件长度 ~HY)$Yp;  
boolean bFirst = true; //是否第一次取文件 e_-g|ukC  
boolean bStop = false; //停止标志 ]W3u~T*  
File tmpFile; //文件下载的临时信息 #jbC@A9Pe  
DataOutputStream output; //输出到文件的输出流 l@4pZkdq  
e"@r[pq-{u  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） G-CL \G\n  
public SiteFileFetch(SiteInfoBean bean) throws IOException D(z
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{ U& GPe
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siteInfoBean = bean; (~@.9&cBD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Q_T,=y  
if(tmpFile.exists ()) |@d(2f8  
{ %<~EwnoT  
bFirst = false; [,bJKz)a  
read_nPos(); fD%/]`y  
} J5b3r1~D"[  
else /@"mQx~[q  
{ kr$)nf  
nStartPos = new long[bean.getNSplitter()];
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nEndPos = new long[bean.getNSplitter()]; "'BDVxp'w  
} r6j[C"@  
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} JP!e'oWxi  
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public void run() /A5=L<T6F  
{ cz
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//获得文件长度 (,"%fc7<i  
//分割文件 padV|hF3(e  
//实例FileSplitterFetch ]:ca=&>  
//启动FileSplitterFetch线程 6cg,L:j#  
//等待子线程返回 9u~C?w  
try{ L^u|=9  
if(bFirst) ?23J(;)s  
{ )^UqB0C6^  
nFileLength = getFileSize(); -0uGzd+m*  
if(nFileLength == -1) A?tCa*b^  
{ "eoPG#]&  
System.err.println("File Length is not known!"); 0MT?}D&TL  
} uWGp>;meO  
else if(nFileLength == -2) '>[ZfT  
{ TaF*ZT2  
System.err.println("File is not access!"); i K@RQi  
} +;H=_~b  
else 4FnePi~i  
{ DKo6lP`  
for(int i=0;i<nStartPos.length;i++) |yNy
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{
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); q2k}bb +  
} -X*.scw  
for(int i=0;i<nEndPos.length-1;i++) !}A`6z  
{ 4PC'7V=S  
nEndPos = nStartPos[i+1]; y2k's  
} %AV3eqghCg  
nEndPos[nEndPos.length-1] = nFileLength; UB] tKn  
} ,>g(%
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} PazWMmI  
:z?T/9,C  
HJr*\%D}1  
//启动子线程 MPp:EH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; //G&=i$  
for(int i=0;i<nStartPos.length;i++) **AJFc  
{ vU/sQt8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h*4wi.-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "% i1zQo&  
nStartPos,nEndPos,i); ;8F6a:\v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <)cmI .J3  
fileSplitterFetch.start(); ,:.8s>+i  
} KW0KXO06a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c5CxR#O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 7F~Jz*,B*W  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b6g9!  
nEndPos = " + nFileLength); 9~,!+#  
// fileSplitterFetch[nPos.length-1].start(); i(u zb<  
: Q,O:  
Z(E.F,k  
//等待子线程结束 bz&9]%S<  
//int count = 0; H
VC|0}  
//是否结束while循环 :U1V 2f'l3  
boolean breakWhile = false; R^E-9S\@  
(1,4egMpR  
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while(!bStop) Ux,dj8=o  
{ F&/}x15  
write_nPos(); p<VW;1bt5  
Utility.sleep(500); 4J[bh  
breakWhile = true; Z\-Gr 2k  
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for(int i=0;i<nStartPos.length;i++) */]1?M@P)  
{ =0@o(#gM  
if(!fileSplitterFetch.bDownOver) Mi!ak  
{ OOsd*nX/  
breakWhile = false; 3e[k9`  
break; (_
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} d{^K8T3  
} d[(%5pw~zL  
if(breakWhile) -mZ{.\9  
break; 5o|u!#6  
or`"{wop  
L'BzefU;04  
//count++; :Ea]baM"  
//if(count>4) {-IRX)m*  
// siteStop();  `Q^Vm3h  
} k/xNqN(  
BW)t2kR&  
zHj_q%A  
System.err.println("文件下载结束！"); KrECAc  
} `O=LQ m`  
catch(Exception e){e.printStackTrace ();} -}JRsQ+rgM  
} atFu KYI  
!hPe*pPVV)  
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//获得文件长度 (7aE!r\Ab  
public long getFileSize() Bq:: 5,v  
{ [h :FJ  
int nFileLength = -1; I'cM\^/h  
try{ BgG+  
URL url = new URL(siteInfoBean.getSSiteURL()); HQ|{!P\/?U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); TLzcQ|  
httpConnection.setRequestProperty("User-Agent","NetFox"); m+'X8}GC#O  
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int responseCode=httpConnection.getResponseCode(); wa9{Q}wSa  
if(responseCode>=400) )&elr,b/y  
{ B
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processErrorCode(responseCode); 20uR?/|@  
return -2; //-2 represent access is error *r3u=oWb  
} -aMwC5iR@  
[C~{g#  
jr5x!@rb  
String sHeader; _nnl+S>K  
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for(int i=1;;i++) @*LESN>T@t  
{ YI?y_S  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y6@A@VJ  
//Utility.log(in.readLine()); ].w$b)G  
sHeader=httpConnection.getHeaderFieldKey(i);
}oTac
 
if(sHeader!=null) ~&IL>2-B  
{ (3G]
-  
if(sHeader.equals("Content-Length")) k@R)_,2HH  
{ 80M4
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); KK*"s^L  
break; ?+#E&F  
} >7V&pH'  
} M*c`@\  
else CD0SXNi"zH  
break; .!t'&eV  
} h:+>=~\  
} ZjJEjw  
catch(IOException e){e.printStackTrace ();} WS0RvBvb  
catch(Exception e){e.printStackTrace ();} Wm ?R
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, v6[#NU_Z  
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Utility.log(nFileLength); Ih95&HsdC  
}FRyG%  
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return nFileLength; 9X{aU)"omQ  
} t UW'E  
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tL4xHa6v]  
//保存下载信息（文件指针位置） 'x10\Q65[  
private void write_nPos() \bb,gRfP  
{ MhB kr{8  
try{ p.1|bXY`  
output = new DataOutputStream(new FileOutputStream(tmpFile)); f;%4
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output.writeInt(nStartPos.length); m[u 6<C  
for(int i=0;i<nStartPos.length;i++) 1<qq69x  
{ ^Q_0Zq^H  
// output.writeLong(nPos); *%cI,}%   
output.writeLong(fileSplitterFetch.nStartPos); jKu"Vi|j>  
output.writeLong(fileSplitterFetch.nEndPos); A|@d4+  
} L*VGdZ
 
output.close(); ;z7iUke0%  
} DI!l.w5P_  
catch(IOException e){e.printStackTrace ();} nyPA
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catch(Exception e){e.printStackTrace ();} D058=}^HE  
} : C;=<$  
P>kS$U)  
r jL%M';  
//读取保存的下载信息（文件指针位置） U07n7`2w  
private void read_nPos() Nr7MSFiL  
{ p<6pmW3  
try{ 15gI-Qb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); JWrvAM$O  
int nCount = input.readInt(); +B'9!t4 2  
nStartPos = new long[nCount]; p2
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nEndPos = new long[nCount]; gzHjD-g-<  
for(int i=0;i<nStartPos.length;i++) s\Cl3  
{ {N;XjV1x  
nStartPos = input.readLong(); 5kJ>pb$/  
nEndPos = input.readLong(); Md[nlz  
} U]ouBG8/  
input.close(); x<=+RYz#^:  
} Xf9VW}`*8  
catch(IOException e){e.printStackTrace ();} 8c3X9;a  
catch(Exception e){e.printStackTrace ();} )mZ`j.  
} A0WQZt!FEN  
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private void processErrorCode(int nErrorCode) jvm "7)h  
{ ipKk
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System.err.println("Error Code : " + nErrorCode); ;mo}$^49*  
} L1"X`Pz[}  
!cE)LG  
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//停止文件下载 T cSj`-  
public void siteStop() -D.6@@%Kc}  
{ JT<Ia  
bStop = true; >1mCjP  
for(int i=0;i<nStartPos.length;i++) TiF$',WMv  
fileSplitterFetch.splitterStop(); }kXF*cVg  
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} ;Z.}~d6>!  
} F+Lq  
//负责部分文件的抓取 g >-iBxml  
**FileSplitterFetch.java K#F~$k|
1B  
*/ z6FG^  
package NetFox; o~^hsm[44J  
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import java.io.*; P
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import java.net.*; <6n(a)L1  
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public class FileSplitterFetch extends Thread { 6z=:x+m  
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String sURL; //File URL ";",r^vr\  
long nStartPos; //File Snippet Start Position Fz)z&WT  
long nEndPos; //File Snippet End Position t_@%4Wn!1L  
int nThreadID; //Thread's ID {v]A`u)  
boolean bDownOver = false; //Downing is over c+|,2e 0T  
boolean bStop = false; //Stop identical a50{gb#  
FileAccessI fileAccessI = null; //File Access interface zc,fJM  
&sWqSS  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException XF{}St~(  
{ 31YzTbl[H  
this.sURL = sURL; )Cyrs~  
this.nStartPos = nStart; d%4!d_I<  
this.nEndPos = nEnd; U4zyhj  
nThreadID = id; tq>QZE
g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 eyl+D sK  
} m[ txKj.=_  
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public void run() yZA}WTGe  
{ "o}3
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while(nStartPos < nEndPos && !bStop)
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{ tX Z5oG7  
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try{ /o![%&-l  
URL url = new URL(sURL); =?T'@C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @;d(>_n  
httpConnection.setRequestProperty("User-Agent","NetFox"); aLuxCobV  
String sProperty = "bytes="+nStartPos+"-"; LYavth`@h  
httpConnection.setRequestProperty("RANGE",sProperty); Eh0R0;l5>  
Utility.log(sProperty); OES+BXGX  
i>q]U:U  
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InputStream input = httpConnection.getInputStream(); {o5E#<)  
//logResponseHead(httpConnection); Ck(D: % ~s  
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byte[] b = new byte[1024]; 6#.z:_  
int nRead; qeSxE`E"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >K;p+( <6  
{ 8KT|ixs  
nStartPos += fileAccessI.write(b,0,nRead); SAc}5.  
//if(nThreadID == 1) m_Z%[@L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); XrtB&h|C  
} ~0t]`<y=  
tX&
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Utility.log("Thread " + nThreadID + " is over!"); +;pdG[N  
bDownOver = true; [|xHXcW  
//nPos = fileAccessI.write (b,0,nRead); UFm E`|le  
} ~%k<N/B  
catch(Exception e){e.printStackTrace ();} VGA?B@  
} q9yY%  
} "+r8izB  
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 ]6W#P7  
//打印回应的头信息 B.;/N220P  
public void logResponseHead(HttpURLConnection con) -`FTWH  
{ >j_,3{eJ  
for(int i=1;;i++) TR5"K{WDx  
{ :_i1)4[!  
String header=con.getHeaderFieldKey(i); GmPNzHDb  
if(header!=null) +KrV!Taf  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); rM<c;iQ  
Utility.log(header+" : "+con.getHeaderField(header)); S;a{wYF6v  
else \O^b|0zc  
break; D%Hz'G0|  
} -?&wD["y  
} UP 75}h9  
73rr"> 9#0  
S3`zB?7,  
public void splitterStop() ke
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{ 0^5SL/2  
bStop = true; `\(Fax  
} 7?qRY9Qu  
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} P+wV.pF|  
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/* uK="#1z cC  
**FileAccess.java +k
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*//文件访问(定位，写) e$45OL  
package NetFox; Ma:xxsH.  
import java.io.*; "+[
:\  
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public class FileAccessI implements Serializable{ i_)j K  
NELQo#kjZ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 1K"``EvNB  
RandomAccessFile oSavedFile; KFkKr>S:  
long nPos; "$;=8O5O  
"/[-U;ck  
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public FileAccessI() throws IOException KtA0 8?B  
{ w6'o<=  
this("",0); nMNAn}~*M  
} sFC&DTb?  
Bi]`e_(}  
#'mb9GWD3  
public FileAccessI(String sName,long nPos) throws IOException M6jP>fbV*  
{  2(YZTaY  
oSavedFile = new RandomAccessFile(sName,"rw"); uB>NwCL
;  
this.nPos = nPos; P)XkqOGpT9  
oSavedFile.seek(nPos); C=t:0.:PJ  
} -P]J:7*0?\  
M3Q#=yy$D$  
G9<pYt{:  
public synchronized int write(byte[] b,int nStart,int nLen) tYC`?HT  
{ - (VV  
int n = -1; `Yn^ -W  
try{ [#fXmW>N/  
oSavedFile.write(b,nStart,nLen); KM*sLC#  
n = nLen; 4r\Sbh  
} KwlN  
catch(IOException e) ]0GOSh  
{ aEW Z*y  
e.printStackTrace (); U\&kT/6vh  
} ? }|;ai  
:+|b7fF  
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return n; mR,p?[P  
} z1aApS  
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} a\$PqOB!  
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/* L[)+J2_<  
**SiteInfoBean.java 2T<QG>;)j  
*/ URck#5  
package NetFox; "!i7U2M'  
:c"J$wT/  
nchhNU  
public class SiteInfoBean { xG 7;Ps4L  
>G92k76G  
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private String sSiteURL; //Site's URL WW2VW-Hk  
private String sFilePath; //Saved File's Path E1_FK1*V;  
private String sFileName; //Saved File's Name !T@>Ld:  
private int nSplitter; //Count of Splited Downloading File b#FN3AsR  
=i~/.Nu&  
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public SiteInfoBean() 5m&{f>]T  
{//nSplitter的缺省值为5 v_J\yW'K  
//default value of nSplitter is 5 o^wj_#ai$  
this("","","",5); WZ&/l 65J  
} Ih!UL:Ckh  
[&k[k)  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) M.1R]x(|  
{ -N(y+~wN  
sSiteURL= sURL; {dhuvB  
sFilePath = sPath; '\H{Y[  
sFileName = sName; 6C9KT;6  
this.nSplitter = nSpiltter; Z%\9y]zs  
dt{|bQLu3  
P1]ucu_y,  
} -q[T0^eS  
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RX4O1Z0  
public String getSSiteURL() )/PvaL  
{ ^ ]SS\=7  
return sSiteURL; D"j =|4S#  
} TKvUBy  
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zNuiBLxDs  
public void setSSiteURL(String value) cRsLt/Wr  
{ %gSqc }v*  
sSiteURL = value; + 1\1Z@\M  
} 4JKB6~Y  
Vj_(55WQ  
g3 6oEz~|  
public String getSFilePath() 8Y3c,p/gS>  
{ ;Jr6  
return sFilePath; eft-]c+*0  
} {H#1wu^]O$  
YiB]}/  
Qzw~\KY:  
public void setSFilePath(String value) {6^c3R[  
{ C_dsYuQ5R  
sFilePath = value; ~;_]U[eOL  
} GeWB"(t  
E)3B)(@&P  
PvBx<i}A  
public String getSFileName() {J%Na&D  
{ N5#qox$D  
return sFileName; ZZA!Y9ia2  
} YR'?fr  
E0$UoP   
9*GwW&M%1_  
public void setSFileName(String value) B]ul~FX  
{ H"WkZX  
sFileName = value; 5)' _3r  
} x=Qy{eIe  
\xkLI:*\  
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public int getNSplitter() 8 Mp2MZ*p  
{ gZ
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return nSplitter; N(vzxx^  
} cR}}NF  
+"Ih'bb`j  
bITOA  
public void setNSplitter(int nCount) #HWz.Wb  
{ 7Gnslp?[U  
nSplitter = nCount; %eGxQDIXg  
} 0{F"b'h  
} DalQ.  
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/* fO[X<|9  
**Utility.java `J[(Dx'y=t  
*/ Bwjd/id q  
package NetFox; v]F q}I"  
o+;=C@,'  
\=Af AO@  
public class Utility { k(C?6Gfj  
'!Ps4ZTn_  
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public Utility() $^ (q0zR~l  
{ >hoIJZP,  
X
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;_amgRP7$  
} TP{lt6wws(  
a3?Dtoy'  
//线程睡眠 -b~MQ/,2  
public static void sleep(int nSecond) ih.UzPg  
{ </t_<I0{  
try{ 1iS9f~  
Thread.sleep(nSecond); `]\4yTd  
} 'G>Ejh@t  
catch(Exception e) x5v^@_: jr  
{ 2_
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e.printStackTrace (); (9';zw   
} LeO ))  
} Qc;`nck  
WLiY:X(+|  
//日志 1,`-n5@J%n  
public static void log(String sMsg) rtvuAFiH  
{ ->n<9  
System.err.println(sMsg); <Xm5re.  
} Oh6;o1UI  
daaUC  
FI.S?gy0   
public static void log(int sMsg) a[\,K4l  
{ S+ymdZ)xZ`  
System.err.println(sMsg);  4D"IAI  
} |}^[f]  
} 6R%c+ok8i  
EAF<PMb  
I|RN/RVN  
/* =}\]i*  
**TestMethod.java j$T2ff6  
*/ |(}uagfrd  
package NetFox; *0{MAm  
p
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-Hh$3Uv  
public class TestMethod { UYW%%5p?  
v!t*Ng  
9r+`j  
public TestMethod() e~$MIHBY]  
{ ///xx/weblogic60b2_win.exe $^IuE0.  
try{ Il2DZ5- )  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -kES]P?2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +6*oO|  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &_,^OE}K_:  
fileFetch.start(); rr3NY$W  
} j_&/^-;e  
catch(Exception e){e.printStackTrace ();} TcZ Ci^1F  
7$x@;%xd  
-2v|d]3qG  
}  ^wb -s  
si=/=h  
\4K8*`$  
public static void main(String[] args) 9XT6Gf56  
{ `>?\MWyu  
new TestMethod(); .}ohnnJB0  
} fTY@{t  
} KK(x)(  
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