http断点续传简单实现（java)

/* MCT'Nw@A  
**SiteFileFetch.java @o-B{EH8  
*/ /l{&iLz[  
package NetFox; ?]rPRV
  
import java.io.*; YOrrkbJ(  
import java.net.*; N |1>ooU[  
#
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public class SiteFileFetch extends Thread { )NO<s0?&  

@
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SiteInfoBean siteInfoBean = null; //文件信息Bean !gLk
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long[] nStartPos; //开始位置 6&
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long[] nEndPos; //结束位置 8`b`QtGf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 0[F:'_  
long nFileLength; //文件长度 rS0DSGDq  
boolean bFirst = true; //是否第一次取文件 zh$}~RG[  
boolean bStop = false; //停止标志 :d8W+|1u  
File tmpFile; //文件下载的临时信息 :iiw3#]  
DataOutputStream output; //输出到文件的输出流 =E&OuX-R  
](B@5-^  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） }@+NN ?P  
public SiteFileFetch(SiteInfoBean bean) throws IOException @Eb2k!T  
{ N-g8}03  
siteInfoBean = bean; zd_HxYrN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5*\\J&H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {ls+dx/  
if(tmpFile.exists ()) SSBg?H'T  
{ yIb,,!y9{  
bFirst = false;
KvQ,;A  
read_nPos(); t |W)  
} cE iu)2*e  
else &/A8-:m  
{ JjXobNQf  
nStartPos = new long[bean.getNSplitter()]; |+U<S~  
nEndPos = new long[bean.getNSplitter()]; rtQHWRUn  
} CU:o*;jP  
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} #&8}<8V  
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public void run() K1?Gmue#I  
{ OTB$V k  
//获得文件长度 )R_E|@"  
//分割文件 K~RoUE<3[  
//实例FileSplitterFetch /?/#B `  
//启动FileSplitterFetch线程 qW_u  
//等待子线程返回 Q>qFM9Z  
try{ CJaKnz  
if(bFirst) % p?brc  
{ r$wZt  
nFileLength = getFileSize(); +]:2\TTGI  
if(nFileLength == -1) xKOq[d/8  
{ CY?G*nS?iK  
System.err.println("File Length is not known!"); RQW6N??C  
} 5~XN>>hp  
else if(nFileLength == -2) ":Edu,6O  
{ gLE7Edcp6V  
System.err.println("File is not access!");  \4ghYQ:  
} Xj+q~4{|vt  
else wyxGe<1  
{ KyP)Qzp  
for(int i=0;i<nStartPos.length;i++) K3GSOD>  
{ ~9Cz6yF  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); i;PL\Er:tX  
} I/x iT  
for(int i=0;i<nEndPos.length-1;i++) jx_4B%kzq  
{ jY!ZkQsVe  
nEndPos = nStartPos[i+1]; $mA5@O~C5\  
} IB9%QW"0  
nEndPos[nEndPos.length-1] = nFileLength; T:asm1BC[  
} 17g^ALs  
} {}>n{_  
pN[0YmY#  
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//启动子线程 ps:f=6m2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; P`1EPF  
for(int i=0;i<nStartPos.length;i++) _DPOyR2  
{  PWgDFL?  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), smAC,-6]~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ^a9 oKI9n  
nStartPos,nEndPos,i); ^ons:$0h  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w8~K/>!f  
fileSplitterFetch.start(); j%Y\A~DV  
} ;SKh  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s]B"qFA  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *j)M]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -dTLunv  
nEndPos = " + nFileLength); ET^|z  
// fileSplitterFetch[nPos.length-1].start(); _q>SE1j+W=  
Y^v
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K%KZO`gO  
//等待子线程结束 10sK]XI  
//int count = 0; }ZZ5].-a<D  
//是否结束while循环 
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boolean breakWhile = false; "u')g&   
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while(!bStop) &$fbP5uAZ  
{ Sj 3oV  
write_nPos(); Ln#a<Rx.E7  
Utility.sleep(500); =)<3pGO  
breakWhile = true; #'o7x'n^  
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for(int i=0;i<nStartPos.length;i++) ('o&Q_  
{ @O3/3vi1  
if(!fileSplitterFetch.bDownOver) M7y|EB))  
{ )xl6,bq3  
breakWhile = false; <ZPZk'53<f  
break; +S{  
} "4}wnu6/  
} T.?k>Ak  
if(breakWhile) ( 76{2  
break; uOk%AL>  
Mn^zYW|(  
@6xGJ,s  
//count++; +QqH}= M  
//if(count>4) Zy]s`aa  
// siteStop(); 0my9l;X   
} ML!
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System.err.println("文件下载结束！"); j64 4V|z  
} $@[)nvV\  
catch(Exception e){e.printStackTrace ();} }~enEZ  
} %JoxYy-  
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//获得文件长度 jqoPLbxT
 
public long getFileSize() H*!5e0~rR  
{ N7.  @FK  
int nFileLength = -1; X
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try{ /#q")4Mf  
URL url = new URL(siteInfoBean.getSSiteURL()); /(6zsq'v|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }ymvC  
httpConnection.setRequestProperty("User-Agent","NetFox"); #Q6w+"  
]if;A)'  
{/UhUG  
int responseCode=httpConnection.getResponseCode(); I"Q<n[g0'  
if(responseCode>=400) LF=c^9t  
{ IKm&xzV-  
processErrorCode(responseCode); %jKH?%Ih  
return -2; //-2 represent access is error u(vw|nj`  
} C6k4g75U2  
?n*fy  
i!~>\r\6\  
String sHeader; lCFU1 GHH  
_nX%#/{  
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for(int i=1;;i++) 4]BJ0+|mT  
{  nP_=GI  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); x0x $  9  
//Utility.log(in.readLine()); kEAhTh&g*  
sHeader=httpConnection.getHeaderFieldKey(i); zA{8C];~  
if(sHeader!=null) 3q~Fl=|.
o  
{ @InJ_
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if(sHeader.equals("Content-Length")) KS! iL=i  
{ (|0b7|'T  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); r@$B'CsLj  
break; 8tZ};="F  
} 46ChMTt  
} KM5 JZZP  
else ec'tFL#u{  
break; <d!6[,W;  
} aJ-}  
} M.k|bh8  
catch(IOException e){e.printStackTrace ();} wznn #j  
catch(Exception e){e.printStackTrace ();} =HPu{K$  
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Utility.log(nFileLength); qc-C>Ra  
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return nFileLength; #<}kISV0  
} Y(z}[`2  
33M}>$ZH  
q%.bnF/Yd  
//保存下载信息（文件指针位置） 4<yK7x  
private void write_nPos() '
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{ %gTVW!q  
try{ $[QcEk  
output = new DataOutputStream(new FileOutputStream(tmpFile)); sX~45u \  
output.writeInt(nStartPos.length); 51/sTx<Z}  
for(int i=0;i<nStartPos.length;i++) Vj7Hgc-,  
{ ohTd'+Lm  
// output.writeLong(nPos);
9RcM$[~  
output.writeLong(fileSplitterFetch.nStartPos); p,s&61]  
output.writeLong(fileSplitterFetch.nEndPos); 4 m$sJ  
} u9@
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output.close(); P'FKk<  
} -7
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catch(IOException e){e.printStackTrace ();} !&0a<~Wi  
catch(Exception e){e.printStackTrace ();} +/Z0  
} 4(sttd_  
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//读取保存的下载信息（文件指针位置） /fC\K_<N  
private void read_nPos() MBv/  
{ LO}z)j~W  
try{ 4]u,x`6C  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); w=$'Lt!  
int nCount = input.readInt(); UGf6i"F  
nStartPos = new long[nCount]; N4+g("  
nEndPos = new long[nCount]; L`pY27|  
for(int i=0;i<nStartPos.length;i++) M%;"c?g  
{ .J:;_4x  
nStartPos = input.readLong(); #}j]XWy  
nEndPos = input.readLong(); Avd *~  
} X=#It&m%s  
input.close(); AA_@\:w^  
} T8mY#^sW_  
catch(IOException e){e.printStackTrace ();} 'W+i[Ep5Q  
catch(Exception e){e.printStackTrace ();} G)4SWu0<t  
} m/" J s  
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private void processErrorCode(int nErrorCode) BUV/twU)  
{ \
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System.err.println("Error Code : " + nErrorCode); U~hCn+0  
} pNSst_!>  
.CvFE~  
+|M{I= 8  
//停止文件下载 8LeKwb  
public void siteStop() u<C$'V  
{ h/{8bC@bi  
bStop = true; p*!q}%U  
for(int i=0;i<nStartPos.length;i++) <YSg~T  
fileSplitterFetch.splitterStop(); ,.q8Xf  
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} .c|9..Cq=  
} OU6^+Ta  
//负责部分文件的抓取 ]p}#NPe5  
**FileSplitterFetch.java AO^]>/7ed  
*/ oM2|]ew)  
package NetFox; c0SX]4} G  
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import java.io.*; oN4G1U Kc  
import java.net.*; "TUPYFK9  
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public class FileSplitterFetch extends Thread { +{'lZa  
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String sURL; //File URL {DSyV:  
long nStartPos; //File Snippet Start Position !4_!J (q%  
long nEndPos; //File Snippet End Position ;i/"$K  
int nThreadID; //Thread's ID /jvOXS\M  
boolean bDownOver = false; //Downing is over c'xUJhEL  
boolean bStop = false; //Stop identical QW,cn7  
FileAccessI fileAccessI = null; //File Access interface >b3@>W  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException qih6me8C  
{ Z%KL[R}^w;  
this.sURL = sURL; 4YBf ~Pp  
this.nStartPos = nStart;
~.FnpMDY  
this.nEndPos = nEnd; )4Bwt`VX  
nThreadID = id; S'|lU@PCl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 <Ak:8&$O  
} 6(,ItMbI  
/%-o.hT  
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public void run() bd.j,4^  
{  Ls lM$  
while(nStartPos < nEndPos && !bStop) }Z^FEd"y  
{ l'W3=,G[?  
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try{ LPb]mC6
#  
URL url = new URL(sURL); #&}%70R)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >s44  
httpConnection.setRequestProperty("User-Agent","NetFox"); Io2,% !D  
String sProperty = "bytes="+nStartPos+"-"; 8TUF w@H%  
httpConnection.setRequestProperty("RANGE",sProperty); t`) 'LT  
Utility.log(sProperty); YmZC?x_{M2  
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InputStream input = httpConnection.getInputStream(); FYxUOO  
//logResponseHead(httpConnection); b8eDD+ulk  
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byte[] b = new byte[1024]; o`oRG)QC  
int nRead; )hePN4edj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }<E sS  
{ [5x+aW%ql  
nStartPos += fileAccessI.write(b,0,nRead); o-L|"3P  
//if(nThreadID == 1) ^ b=5 6~[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EPQ&?[6  
} M4R%Gr,La  
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Utility.log("Thread " + nThreadID + " is over!"); Ar\IZ_Q  
bDownOver = true; >+zAWK9  
//nPos = fileAccessI.write (b,0,nRead); `MN&(!&C*  
} u!hq
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catch(Exception e){e.printStackTrace ();} Bidqf7v  
} 6(\q< fx  
} q]2}UuM|U  
Sr4dY`V*:z  
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//打印回应的头信息 R~U2/6V  
public void logResponseHead(HttpURLConnection con) ]|H]9mys98  
{ &z7N\n  
for(int i=1;;i++) 
.;]YJy  
{ 9OE_?R0c!  
String header=con.getHeaderFieldKey(i); ]H@v  
if(header!=null) r0rJ.}!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &f (sfM_n  
Utility.log(header+" : "+con.getHeaderField(header)); x0}<n99qE  
else .%-6&%1  
break; Tb>IHoil  
} 8:;u v7p  
} k#{lt-a/  
9\\@I =;  
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public void splitterStop() T2c_vY  
{ J"m%q\'  
bStop = true; qg) Af  
} 6$xo# }8  
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} }TXp<E"\  
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`
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/* a!s.850@  
**FileAccess.java ymzPJ??
!  
*//文件访问(定位，写) 3j[w -Lfp  
package NetFox; #n6FQ$l8m  
import java.io.*; *y":@T  
%[+a[/  
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public class FileAccessI implements Serializable{ .j'@K+<45  
Z<$E.##  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8`R +y  
RandomAccessFile oSavedFile; D}k-2RM2k  
long nPos; ,_wm,  
E@\d<c.  
h^.tomg8  
public FileAccessI() throws IOException //`cwnjp  
{ RE(=! 8lGR  
this("",0); f4A4  
} ,?7xb]h  
{="Su{i}}  
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public FileAccessI(String sName,long nPos) throws IOException dA_V:HP  
{ \E ? iw.}  
oSavedFile = new RandomAccessFile(sName,"rw"); C7XS6Nqu  
this.nPos = nPos; {7
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oSavedFile.seek(nPos); K%aPl~e  
} #w%a m`+  
=+SVzK,+3  
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public synchronized int write(byte[] b,int nStart,int nLen) Nv*E .|G  
{ S4aHce5PXA  
int n = -1; a V+o\fId  
try{ 2f}K#i8  
oSavedFile.write(b,nStart,nLen); )Yy#`t
 
n = nLen; ,_5YaX:<4  
} priT7!  
catch(IOException e)  01UR  
{ 
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e.printStackTrace (); ib""Fv7{  
} q|Pt>4c5?  
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8f6;y1!;  
return n; R|Q_W X  
} GWA!Ab'<U  
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} N.Wdi  
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/* qk+{S[2j  
**SiteInfoBean.java 95gsv\2  
*/ wn A%Nh7  
package NetFox; ftI+#0?[!  
0F0Q=dZ  
Aa\=7  
public class SiteInfoBean { $<>EwW  
bVAgul=__  
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private String sSiteURL; //Site's URL ;
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private String sFilePath; //Saved File's Path 8#d1}Y  
private String sFileName; //Saved File's Name vwqN;|F  
private int nSplitter; //Count of Splited Downloading File kUaGok?  
mC[U)` ey  
9Qs"X7iH  
public SiteInfoBean() w?$u!X  
{//nSplitter的缺省值为5 kT }'"  
//default value of nSplitter is 5 jhEg#Q$  
this("","","",5); Jq+$_Uqd  
} l3Bxi1k[C  
[
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $bi_i|?  
{ D@4&@>  
sSiteURL= sURL; ~b6<uRnM.  
sFilePath = sPath; kvgs $  
sFileName = sName; Y+_5"LV  
this.nSplitter = nSpiltter; 7N59B z  
dD.d?rnZq7  
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} U)I `:J+A  
C +?@iMh  
D8D!16_  
public String getSSiteURL() +^&v5[$R  
{ T m@1q!G  
return sSiteURL; 3}#XA+Z  
} b[[6X  
;iC'{S  
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public void setSSiteURL(String value) PqJ*   
{ =[)N6XV3  
sSiteURL = value; y!6:  
} b\0Q:  
.dKRIFo  
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w|  
public String getSFilePath() 7U[L\1zS  
{ | 8L`osg  
return sFilePath; %d[xr h  
} rX>y>{w~  
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L]}RSE2  
public void setSFilePath(String value) 2bn@:71`  
{ ">vYEkZ3  
sFilePath = value; 4wj|  
} hpz*jyh8  
^3)2]>pW  
(~pEro]?+)  
public String getSFileName() ~~:8Yv[(  
{ ;Y|~!%2~  
return sFileName; 5fx,rtY2sQ  
} > v!c\  
\Af|$9boHz  
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public void setSFileName(String value) =W
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{ ! 7*_
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sFileName = value; F/od,w9_  
} ~q T1<k  
yDyeP{  
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public int getNSplitter() zI:5I@ X  
{ d,rEEc Y  
return nSplitter; *J
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} C.B}Py+   
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 6[|<  
public void setNSplitter(int nCount) ,8o*!(uO2  
{ :6k DUFj}
 
nSplitter = nCount; u r.T YKF  
} y" 6~9j  
} =O'%)Y&  
]|LaMMD  
hCvLwZ?LF  
/* Ce'2lo  
**Utility.java +ZA\M:^b  
*/ 6BN(^y#-X  
package NetFox; vgW1hWmHJ  
Cz);mOb%M%  
4Z~Dxo  
public class Utility { ^21f^>k(  
5F sj_wFk  
|Sv#f2`  
public Utility() :+^$?[6]  
{ `L*;58
MA  
iN4'jD^oP  
Qp{-!*  
} 6ym)F!t8l  
|wb(rua  
//线程睡眠 ?| LB:8  
public static void sleep(int nSecond) <d&)|W  
{ W>wi;Gf#  
try{ 2-c0/?_4  
Thread.sleep(nSecond); VrE5^\k<a  
} ^?]H$e  
catch(Exception e) LP-Q'vb<=  
{ <.(/#=2  
e.printStackTrace (); z slEUTj)  
} u&_U CJ
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} @OY-(cW  
0\ w[_H  
//日志 *#^1rKGWK  
public static void log(String sMsg) qq_,"~  
{ ^`
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System.err.println(sMsg); ~d `4W<1a  
} }<h. chz,  
/P"\+Qp  
:QL p`s  
public static void log(int sMsg) pvUoed\  
{ :Sn3|`HDm  
System.err.println(sMsg); 4"(zi5`e  
} OLup`~  
} G(\1{"!  
}~'Wz*Gm  
"}+/0$F  
/* d@f2Vxe7  
**TestMethod.java ;OJ0}\*iP8  
*/ swq!Sp  
package NetFox; fToI,FA
 
5t?2B]  
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public class TestMethod { Rs[]
i;  
. \0=1P:  
*9(1:N;#  
public TestMethod() jyH_/X5i7  
{ ///xx/weblogic60b2_win.exe K/+C6Y?  
try{ 10IPq#Jj  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ",V5*1w  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TPFmSDq  
SiteFileFetch fileFetch = new SiteFileFetch(bean); f:&OOD o  
fileFetch.start(); "]V|bz o0a  
}
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catch(Exception e){e.printStackTrace ();} ~RAH -]  
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} iX6jvnJ:/  
k\%v;3nBK  
<uwCP4E  
public static void main(String[] args) O9)}:++T  
{ FNEmGz/4  
new TestMethod(); ymX,k|lh  
} wR$8drn]Rq  
} vnC&1  
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