http断点续传简单实现（java)

/* xe:' 8J6L  
**SiteFileFetch.java UOI^c  
*/ H:}}t]E  
package NetFox; ^"6f\  
import java.io.*; ~ l )t|'6  
import java.net.*; $+VgDe5{S  
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public class SiteFileFetch extends Thread { mY2:m(9"5  
b :\D\X  
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SiteInfoBean siteInfoBean = null; //文件信息Bean g^lFML| %  
long[] nStartPos; //开始位置 =y;@?=T  
long[] nEndPos; //结束位置 v&0d$@6/U  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )mD\d|7f  
long nFileLength; //文件长度 pDDG_4E>  
boolean bFirst = true; //是否第一次取文件 t[O+B6  
boolean bStop = false; //停止标志 <c%n?QK{  
File tmpFile; //文件下载的临时信息 V9jFjc?  
DataOutputStream output; //输出到文件的输出流 pcpxe&S  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `!Ln|_,d  
public SiteFileFetch(SiteInfoBean bean) throws IOException Y^eX@dEFR  
{ u~Lu<3v  
siteInfoBean = bean; x`2p
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); x70N8TQ_gK  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -uR{X G. D  
if(tmpFile.exists ()) mTd<2Hy  
{ #eEvF  
bFirst = false; y9 uVCR
 
read_nPos(); i7v/A&Rc  
} ~= 9Vv  
else 02M7gBS  
{ &t[|%c*D&  
nStartPos = new long[bean.getNSplitter()]; &wGg6$  
nEndPos = new long[bean.getNSplitter()]; rt;gC[3\  
} vl~%o@*_  
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} # ITLz!gE  
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public void run() Oy'0I,  
{ _W+Q3Jx-(  
//获得文件长度 $~o3}&az  
//分割文件 
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//实例FileSplitterFetch R<j<.h  
//启动FileSplitterFetch线程 N l|^o{#  
//等待子线程返回 z|%Bh  
try{ o}!&y?mp  
if(bFirst) e[p^p!a  
{ W9jNUZVXE#  
nFileLength = getFileSize(); :~r#LRgc  
if(nFileLength == -1) Ph"iX'J  
{ 3:O+GQ*  
System.err.println("File Length is not known!"); W:>J864!  
} mS7E_A8  
else if(nFileLength == -2)  uE"2kn  
{ ]-rczl|o  
System.err.println("File is not access!"); EFNdiv$wF  
} wLSjXpP8  
else Ei~]iZ}  
{ #mTMt;x  
for(int i=0;i<nStartPos.length;i++) Ctj8tK
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{ '}fel5YV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 5Q;dnC  
} [wIKK/O  
for(int i=0;i<nEndPos.length-1;i++) AG=9b  
{ s#`cX0L)  
nEndPos = nStartPos[i+1]; yHtGp%j  
} QS%,7'EG  
nEndPos[nEndPos.length-1] = nFileLength; wK ][qZ ]  
} {V=vnL--  
} o] S`+ZcV  
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B,:23[v  
//启动子线程 M3PVixli3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; }kv)IJ  
for(int i=0;i<nStartPos.length;i++) Tu'E{Hw  
{ +E)e1:8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `^`9{@~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 2}>go^#O/w  
nStartPos,nEndPos,i); }o{!}g9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L:Ed-=|Uw  
fileSplitterFetch.start(); ?^eJ:  
} f5N<3m=  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w[M5M2CF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Hq79/wKj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", QZ:v  
nEndPos = " + nFileLength); myffYK,  
// fileSplitterFetch[nPos.length-1].start(); T+3k$G[e/  
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bL#sn_(m  
//等待子线程结束 J;7s/YH^  
//int count = 0; @b8X%0B7  
//是否结束while循环 ScsWnZ  
boolean breakWhile = false; u`nt\OF  
'|J)ds  
,%.:g65%  
while(!bStop) a?l_-Fi  
{ !HbqbS22  
write_nPos();
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Utility.sleep(500); .;cxhgU  
breakWhile = true; <&*#famX  
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for(int i=0;i<nStartPos.length;i++) fWqv3nY^  
{
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if(!fileSplitterFetch.bDownOver) ;cnnqT6  
{ ,q/tyGj  
breakWhile = false; \;'_|bu3.  
break; ;}$Z 80  
} VoWA
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} m]Hb+Y=;h  
if(breakWhile)
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break; r=xTs,xx  
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//count++; )Fw @afE~  
//if(count>4) AfuXu@UZ_/  
// siteStop(); nmTm(?yE  
} zK[ 7:<  
5/zf x  
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System.err.println("文件下载结束！"); ;*n_N!v  
} pE~9o 9  
catch(Exception e){e.printStackTrace ();} [BJ$|[11  
} rDK;6H:u{  
$:T<IU[E  
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//获得文件长度 XPGL3[w\V  
public long getFileSize() 0EcC  
{ |Gf1^8:C9  
int nFileLength = -1; tCd{G c  
try{ UZ[/aq  
URL url = new URL(siteInfoBean.getSSiteURL()); !5yRWMO9X~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); bEoB;]  
httpConnection.setRequestProperty("User-Agent","NetFox"); +e&m#d  
~W]#9&yQ  
:<'i-Ur8  
int responseCode=httpConnection.getResponseCode(); A73V6"  
if(responseCode>=400) GMVC&^  
{ h[Ndtq>3{  
processErrorCode(responseCode); 2V#c[%vI  
return -2; //-2 represent access is error V=G b>_d  
} pil0,r $D  
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String sHeader; 7yc9`j}]  
*%P>x}6w3  
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for(int i=1;;i++) pCB 5wB  
{ u=_b
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5bu[}mJ  
//Utility.log(in.readLine()); .5jnKU8NF  
sHeader=httpConnection.getHeaderFieldKey(i); i}v}K'`  
if(sHeader!=null) *u:;:W&5y  
{ ;:#?~%7>  
if(sHeader.equals("Content-Length")) e;&{50VY  
{ CVyx lc>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <M5{.`o  
break; jsZiARTZRl  
} /Bg6z m  
} l(3'Re  
else se^NQ=  
break; 2)HxW
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} 1NE!=;VOl  
} q\\8b{~  
catch(IOException e){e.printStackTrace ();} E|F!S(.:,M  
catch(Exception e){e.printStackTrace ();} N'lGA;}i  
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Utility.log(nFileLength); WI*^+E&=*  
-dc"N|.  
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return nFileLength; 9^#zxmH)  
} b@{%qh,C  
2|T|K?R^  
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//保存下载信息（文件指针位置） +
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private void write_nPos() }"g21-T^  
{ l`~a}y"n  
try{ 4U LJtM3  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?9wFV
/  
output.writeInt(nStartPos.length); SG(%d^x
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for(int i=0;i<nStartPos.length;i++) C{d8~6  
{ `g4Ekp'Rp[  
// output.writeLong(nPos); }(f.uN_v  
output.writeLong(fileSplitterFetch.nStartPos); gLXvw]  
output.writeLong(fileSplitterFetch.nEndPos); V8KTNt%  
} h=iA
;B^>  
output.close(); Xa@ _^oL  
} kb>Vw<NtE  
catch(IOException e){e.printStackTrace ();} a`[?,W:q  
catch(Exception e){e.printStackTrace ();} |2t7G9[n  
} o1p$9PL\:  
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//读取保存的下载信息（文件指针位置） #G[ *2h~99  
private void read_nPos() s&_
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{ (d5vH)+A  
try{ pR@GvweA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )$lSG}WD  
int nCount = input.readInt(); @Le ^-v4  
nStartPos = new long[nCount]; ~q'w),bE"Q  
nEndPos = new long[nCount]; Sug~FV?k$e  
for(int i=0;i<nStartPos.length;i++) 8zWBXV  
{ (:j+[3Ht  
nStartPos = input.readLong(); `/gEKrhL-  
nEndPos = input.readLong(); u$Pf.#  
} Gct&}]3pm  
input.close(); ;*j6d3E  
} P&-D0T_  
catch(IOException e){e.printStackTrace ();} @]y{M;  
catch(Exception e){e.printStackTrace ();} )"i>R ~*  
} mhJOR'2  
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k #,Gfs  
private void processErrorCode(int nErrorCode) w ufKb.4`  
{ 9Ww=hfb5UW  
System.err.println("Error Code : " + nErrorCode); *'`3]!A  
} ~'Qpf 8)  
a\[fC=]r:  
mNBpb}  
//停止文件下载 p)[BB6E  
public void siteStop() pT_e;,KW U  
{ :(S/$^U  
bStop = true; ]X"i~$T1S  
for(int i=0;i<nStartPos.length;i++) [6/%V>EM  
fileSplitterFetch.splitterStop(); 'wT./&Z  
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} S8W_$=4  
} DoCQFSL  
//负责部分文件的抓取 ?O.6r"  
**FileSplitterFetch.java 2Xj-A\Oh~  
*/ qu#@F\gX  
package NetFox; q*<J$PI  
q=E}#[EgY  
[V#&sAe  
import java.io.*; (X`t"*y"  
import java.net.*; *`pec3"  
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public class FileSplitterFetch extends Thread { $.3CiM}~  
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v^lm8/}NO  
String sURL; //File URL ''\cBM!  
long nStartPos; //File Snippet Start Position 7,&]1+n  
long nEndPos; //File Snippet End Position 8HH.P`Vk#  
int nThreadID; //Thread's ID g:HbmXOBpj  
boolean bDownOver = false; //Downing is over \A~I>x  
boolean bStop = false; //Stop identical E{k%d39>  
FileAccessI fileAccessI = null; //File Access interface L[[H&#\  
)l!&i?h%  
9T0wdK]  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException J1y2Qw$G  
{ P".qL5  
this.sURL = sURL; $nD k mKl  
this.nStartPos = nStart; ~]_jKe4W  
this.nEndPos = nEnd; (EF$^FYPK  
nThreadID = id; I;":O"ij\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 omUl2C  
} ;ZqD60%\  
\<MTY:  
a\.OL}"   
public void run() E<m"en&v  
{ Dk{nOvZu<  
while(nStartPos < nEndPos && !bStop) EBn:[2  
{ Vo9)KxR  
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try{ @l6dJ  
URL url = new URL(sURL); <
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3Ns:O2|  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2QuypVC ]  
String sProperty = "bytes="+nStartPos+"-"; u!Eu
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httpConnection.setRequestProperty("RANGE",sProperty); )mo|.L0  
Utility.log(sProperty); MgK(gL/&[  
[#@p{[?r  
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InputStream input = httpConnection.getInputStream(); NYV0<z@M2M  
//logResponseHead(httpConnection); gu.))3D9  
&MGgO
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byte[] b = new byte[1024]; A`8}J4  
int nRead; ~zOU/8n ,F  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) V:"\(Y  
{ va*>q-QCr  
nStartPos += fileAccessI.write(b,0,nRead); cF<DUr)Ve  
//if(nThreadID == 1) pcxl2I  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7QL) }b.H  
} >5@ 0lYhH  
b!tZbX#  
fO}1(%}d  
Utility.log("Thread " + nThreadID + " is over!"); W,oV$ s^  
bDownOver = true; wCEfR!i  
//nPos = fileAccessI.write (b,0,nRead); N@`9 ~JS  
} v_F?x!  
catch(Exception e){e.printStackTrace ();} Z(`K6`KM  
} Z_ *ZUN?B  
} w7ABnX  
"@'9+$i6  
=VI`CBQ/Um  
//打印回应的头信息 1ZH8/1gWI  
public void logResponseHead(HttpURLConnection con) x:wq"X  
{
1XKIK(l  
for(int i=1;;i++) YwTtI ID%  
{ $HnD|
_*  
String header=con.getHeaderFieldKey(i); UtW3KvJ#=  
if(header!=null) +wgUs*(W  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6 VJj(9%  
Utility.log(header+" : "+con.getHeaderField(header)); ,4I6RwB.  
else l[j0(T  
break; Y?SJQhN6W  
} oTa+E'q  
} C&K(({5O  
=|t1eSzc  
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public void splitterStop() )t 7HioQ  
{ a{YVz\?d}  
bStop = true; R$'nWzX#  
} sBG(CpQ  
#[rFep  
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} j:<T<8.o  
sU3V)7"  
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/* "Q!{8 9Y  
**FileAccess.java +?eAaC7s  
*//文件访问(定位，写) s5|)4Zac  
package NetFox; 8{^GC(W{]  
import java.io.*; Yy;1N{dbT  
Z`h_oK#y15  
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public class FileAccessI implements Serializable{ O*"wQ50Ou  
%[F;TZt  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6*oTT(0<p  
RandomAccessFile oSavedFile; |"&4"nwa  
long nPos; N@ tb^M  
~9 nrS9)  
t#Yh!L6>  
public FileAccessI() throws IOException S^_yiV S  
{ E*]L]vR  
this("",0); :EAfD(D{)  
} B ~bU7.Cd  
3gXUfv2ID  
#3jZ7RqzQ  
public FileAccessI(String sName,long nPos) throws IOException A)0m~+?{J  
{ 'n`$c{N<tM  
oSavedFile = new RandomAccessFile(sName,"rw"); , Vr6  
this.nPos = nPos; ,tc]E45  
oSavedFile.seek(nPos); obkv ]~  
} (.t:sn"P  
}{PtQc6RL!  
~oyPmIcb  
public synchronized int write(byte[] b,int nStart,int nLen) *J-jr8&  
{ N^j''siB  
int n = -1; h v+i{Z9!]  
try{ PltPIu)F  
oSavedFile.write(b,nStart,nLen); C'"6@-~  
n = nLen; eNKdub  
} x?$Y<=vT  
catch(IOException e) #rC+13  
{ P=i |{vv(  
e.printStackTrace (); :~(^b;yhZ  
} 3Q6
#m3AWY  
_dY}86{  
 Hh/#pGf2  
return n; KWkT 9[H  
} ~#xRoB
y3  
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} $:P~21,  
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/* P,], N)  
**SiteInfoBean.java D{}\7qe  
*/ &Vm[5X
W  
package NetFox; .5zJ bZ9  
3<SC`6'?  
m)2U-3*iX  
public class SiteInfoBean { -M9 4
F  
4df1)<}U-  
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private String sSiteURL; //Site's URL 4WnxJ]5`  
private String sFilePath; //Saved File's Path g9Ll>d)tE3  
private String sFileName; //Saved File's Name L32ki}2  
private int nSplitter; //Count of Splited Downloading File OuH]Y70(  
[! o-F;  
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public SiteInfoBean() 'f!Jh<i  
{//nSplitter的缺省值为5 ;bbEd'  
//default value of nSplitter is 5 Mqy`j9FbL  
this("","","",5); Ku# _   
} ;W"[,#2TM  
a+Nd%hoe  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "*WXr$  
{ 1Sr}2@>  
sSiteURL= sURL; IVKE dwA  
sFilePath = sPath; #,pL
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sFileName = sName;  )BB a  
this.nSplitter = nSpiltter; we?#)9Q<  
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vO  
O*7~t17  
} ;RYKqUE  
[HfFC3U  
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public String getSSiteURL() LdL\B0^l  
{ djp(s$:{4  
return sSiteURL;  O@$i
 
} C\[UAxZ3X  
&kE|~i:=,9  
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public void setSSiteURL(String value) hkxZ=l  
{ bL%)k61G_v  
sSiteURL = value; %(6WrE5F6  
} ]vrs?  
z@j&vW  
D.}b<kDD  
public String getSFilePath() <k1gc
,*  
{ %mJ)pMV  
return sFilePath; 03y<'
n  
} CaMG$X&O  
5
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public void setSFilePath(String value) .BvV[`P  
{ 8a{gEZT,  
sFilePath = value; 6P8X)3CE<T  
} o\#e7Hqbh  
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N3)EG6vE*  
public String getSFileName() "M]]H^r5  
{ `pr,lL  
return sFileName; Z$@Nzza-  
} I`l<}M  
hGLBFe#3  
.#}R$}e+  
public void setSFileName(String value) )1ciO+_  
{ ~Gza$ K  
sFileName = value; %,BJkNV  
} t/w>t! q  
^EZoP:x(oE  
e$Ej7_.#;  
public int getNSplitter() W:G*t4i  
{ R<U<Y'Y  
return nSplitter; +X%yF{^m(  
} Vow+,,oh  
c2QC`h(Wb  
C;|Ru*  
public void setNSplitter(int nCount) tee%E=P  
{ uU0'y4=  
nSplitter = nCount; KAGq\7  
} ~?FKww|_*J  
} 9,IGZ55C  
FqySnrJQ  
`B~%TEvMh  
/* cD]t%`*  
**Utility.java P=.W.oS  
*/ Pt$7U[N  
package NetFox; hO8B]4=&*  
a,.9eHf  
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public class Utility { 9j/B3CjW  
C|+5F,D  
4I$#R  
public Utility() _#I0m(  
{ 8oK30?  
e5dwq  
w$_ooQ(_;Q  
} BTB,a$P/  
JkTL+obu  
//线程睡眠 rz(DZV  
public static void sleep(int nSecond) gg=z.`}  
{ 98l#+4+  
try{ '`n\YO.N  
Thread.sleep(nSecond); ufmFeeg  
} lxbZM9A2  
catch(Exception e) q;+qIV&.:  
{ Z=ho7i  
e.printStackTrace (); Z(#a-_g  
} sy~mcH:%+  
} oPi)#|jcb  
Ty>`rn  
//日志 Wjp<(aY[  
public static void log(String sMsg) Mw<1  
{ CR<*<=rI  
System.err.println(sMsg); 5}f$O  
} 1K!7FiqY  
(5SI!1N  
%tpjy,
 
public static void log(int sMsg)
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{ =6>mlI>i  
System.err.println(sMsg); )s M}BY  
} xf|=n  
} 3oj30L.  
HG3jmI+u>  
>%{h_5  
/* +IMP<  
**TestMethod.java ,ua]h8  
*/ :t(}h!7  
package NetFox; 'O CVUF,  
U^.$k-|k  
Fik*7!XQ8  
public class TestMethod { *fl1 =Rfr  
!JJY(o  
"p<f#s}  
public TestMethod() wI)W:mUZZ  
{ ///xx/weblogic60b2_win.exe ]RV6(|U4_  
try{ ^#;2 Pd>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); zZkwfF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !5ppA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >LLFe~9`g  
fileFetch.start(); h)sc-e
 
} H}A67J9x  
catch(Exception e){e.printStackTrace ();} Oa{M9d,l  
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?(F~9V  
} Ltc>@  
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${e{#  
public static void main(String[] args) ?;\YiOTda  
{ z`{x1*w_  
new TestMethod(); =*t)@bn  
} iYFM@ta  
} VPK)HzPG,  
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