http断点续传简单实现（java)

/* -u8@ .  
**SiteFileFetch.java v $pARt  
*/ 2\s-4H| q  
package NetFox; *[vf47)r!  
import java.io.*; '{7A1yJnY%  
import java.net.*; mTs[3opg  
]B5\S  
)<3WVvB  
public class SiteFileFetch extends Thread { 5_`.9@eh.  
5[Q44$a{  
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SiteInfoBean siteInfoBean = null; //文件信息Bean F htf4  
long[] nStartPos; //开始位置 @${!C\([1  
long[] nEndPos; //结束位置 e7hPIG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 | C2k(  
long nFileLength; //文件长度 -iJ[9O  
boolean bFirst = true; //是否第一次取文件 pq4+n'uO  
boolean bStop = false; //停止标志 [&Qrk8EN  
File tmpFile; //文件下载的临时信息 _ H@pYMNH  
DataOutputStream output; //输出到文件的输出流 Dnd  
3$y]#
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） #z5'5|3  
public SiteFileFetch(SiteInfoBean bean) throws IOException my04>6j0  
{  c<4pu  
siteInfoBean = bean; =B?uNoe  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); K IqF"5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >\>HRyt%  
if(tmpFile.exists ()) H5qa7JMZ  
{ >iG`  
bFirst = false; p*dez!  
read_nPos(); IAtc^'l#  
} ^ qE4:|e  
else 'x!q*|zF2  
{ b"f4}b  
nStartPos = new long[bean.getNSplitter()]; Q2Q`g`*O:  
nEndPos = new long[bean.getNSplitter()]; 
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} qed; UyN  
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} S:oZ&   
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public void run() 0"<gg5  
{ op"Cc  
//获得文件长度 <xc"y|7X  
//分割文件 MiR
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//实例FileSplitterFetch sG^b_3o)A  
//启动FileSplitterFetch线程 d/* [t!  
//等待子线程返回 FiIN\  
try{ >~ne(n4qy  
if(bFirst) ~v<r\8`OI2  
{ h~F uuL  
nFileLength = getFileSize(); BD9` +
9
 
if(nFileLength == -1) P=S)V  
{ 43 |zjE  
System.err.println("File Length is not known!"); RtF_p {s  
} \DfvNeF  
else if(nFileLength == -2) V{a7@_y  
{ VS 8|lgQ  
System.err.println("File is not access!"); -;Hd_ ~O>j  
} Q&n|tQ*4  
else }3vB_0[r  
{
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for(int i=0;i<nStartPos.length;i++) /e\} qq  
{ LkNfcBa_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); xu_Tocvop  
} k*^.-v  
for(int i=0;i<nEndPos.length-1;i++) @++ X H}  
{ ;/e!!P]jP  
nEndPos = nStartPos[i+1]; *A8CJ  
} s7&%_!4  
nEndPos[nEndPos.length-1] = nFileLength; (o e;pa  
} )Oa"B;\j  
} DhB:8/J  
|!&,etu  
~1}NQa(  
//启动子线程 xb1)ZJH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &_!BMzp4  
for(int i=0;i<nStartPos.length;i++) a@m>S$S  
{ >Z>*Iz,LP  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t}TtWI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), cZ o]*Gv.  
nStartPos,nEndPos,i); 1R,n[`}h  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YB)1dzU  
fileSplitterFetch.start(); ] niWRl
 
} +IJpqFH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZXr]V'Q?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `[Lap=.'.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ry/NfF=  
nEndPos = " + nFileLength); y ?Q"-o (  
// fileSplitterFetch[nPos.length-1].start(); xG<S2R2VQh  
(-"A5(X:/  
W%Um:C\I  
//等待子线程结束 !.p!  
//int count = 0; IO,kP`Wcx  
//是否结束while循环 ZZlR:D  
boolean breakWhile = false; )Cx8?\/c=x  
AV%Q5Mi}  
\ fwf\&  
while(!bStop) J"[OH,/_  
{ >)5rOU  
write_nPos(); :G}tvFcOAF  
Utility.sleep(500); z*x6V0'yt  
breakWhile = true; 7N'F]x  
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for(int i=0;i<nStartPos.length;i++) f+/^1~^  
{ 8t6h^uQ  
if(!fileSplitterFetch.bDownOver) SxQ|1:i%  
{ #|$7. e  
breakWhile = false; _NZ) n)  
break; E$Ge# M@dM  
} eKu&_q  
} Oq!u `g9  
if(breakWhile) /$q;-/DnTZ  
break; Ppx*
  
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//count++; O4-UVxv}  
//if(count>4) sCnZ\C@u  
// siteStop(); hO(HwG?8t  
} sIELkF?.  
|,yS>kjp  
KY_qK)H  
System.err.println("文件下载结束！"); 9jvg[H  
} SX FF  
catch(Exception e){e.printStackTrace ();} Ufo-AeQo  
} OTV)#,occ  
h]'fX  
^?juY}rZ=|  
//获得文件长度 TyK; q{  
public long getFileSize() sI^1c$sBN  
{ j*6!7u.,K  
int nFileLength = -1; r&TxRsg{  
try{ gi"v${R  
URL url = new URL(siteInfoBean.getSSiteURL()); T;FzKfT|
  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C
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httpConnection.setRequestProperty("User-Agent","NetFox"); VD=$:

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int responseCode=httpConnection.getResponseCode(); ob*2V!"  
if(responseCode>=400) -(1e!5_-@  
{ f0hi70\(X  
processErrorCode(responseCode); X^@d
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return -2; //-2 represent access is error DPe`C%Oc1  
} .{8lG^0U<  
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String sHeader; TZHqn6  
{'X"9@  
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for(int i=1;;i++) O&X-)g=  
{ 95(VY)_6#A  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %%DK?{jo`  
//Utility.log(in.readLine()); bqLv81V  
sHeader=httpConnection.getHeaderFieldKey(i); j#~4JGZt  
if(sHeader!=null) &V2G<gm0  
{ LpF6e9V\Wp  
if(sHeader.equals("Content-Length")) (/N`Wu  
{ =]Ek12.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &E9%8Q)r(  
break; 'dht5iI;Yw  
} 9PR&/Q F5  
} s ^}V  
else ?Ts Z_  
break; eM~i (]PY  
} 82w<q(  
} 979L]H#  
catch(IOException e){e.printStackTrace ();} mV'd9(s?  
catch(Exception e){e.printStackTrace ();} SD697L9  
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Utility.log(nFileLength); 2<J82(4j  
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return nFileLength; ) .]Z}g&  
} ?s_q
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//保存下载信息（文件指针位置） oF3#]6`;/  
private void write_nPos() m\k$
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{ lca.(3u  
try{ @%jzVF7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &0o&!P8CB  
output.writeInt(nStartPos.length); D/giM#"  
for(int i=0;i<nStartPos.length;i++) 0Ifd!  
{ *qR tk  
// output.writeLong(nPos); '~a!~F~>  
output.writeLong(fileSplitterFetch.nStartPos); iE&`Fhf?  
output.writeLong(fileSplitterFetch.nEndPos); `bxgg'V  
} T8RQM1D_s  
output.close(); zU}0AVlIL:  
} XCt}>/"s\h  
catch(IOException e){e.printStackTrace ();} h<QXr'4+  
catch(Exception e){e.printStackTrace ();} LAvAjvRc  
} AU7c = H:?  
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//读取保存的下载信息（文件指针位置） 00$W>G
r  
private void read_nPos() $U6)km4  
{ vu*08<M~i|  
try{ T[7-3[w<)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Aimgfxag  
int nCount = input.readInt(); g;*~
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nStartPos = new long[nCount]; 4f/8APA  
nEndPos = new long[nCount]; Jl4zj>8~  
for(int i=0;i<nStartPos.length;i++) +^%F8GB  
{ LS \4y&J40  
nStartPos = input.readLong(); M9iu#6P  
nEndPos = input.readLong(); Oc"2|X  
} B,A/ -B\  
input.close(); :|d3BuY  
} / AW]12_  
catch(IOException e){e.printStackTrace ();} .]jKuTC\<  
catch(Exception e){e.printStackTrace ();} }t-{,0  
} "q%Q[^
b  
]~|zY5i!  
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private void processErrorCode(int nErrorCode) w1.KRe{M  
{ ++FMkeHZ  
System.err.println("Error Code : " + nErrorCode); 6T)D6;@L  
} 8S)k]$wf%  
L>xN7N3&m  
J \G8g,@  
//停止文件下载 BG=h1ybz  
public void siteStop() |}#Rn`*2y  
{ sbG3,'i)  
bStop = true; q3 9RD  
for(int i=0;i<nStartPos.length;i++) *V
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fileSplitterFetch.splitterStop(); 2.CI^.5&  
A}W&=m8!  
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} m'a3}vRV(  
} rH & ^SNc  
//负责部分文件的抓取 p>!`JU`{?  
**FileSplitterFetch.java
tcmG>^YM  
*/ E5Z,4B  
package NetFox; ?-Oy/Y K  
<b{ApsRJf  
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import java.io.*; BE:GB?XBH  
import java.net.*; MQLa+I,S4  
<@JK;qm>S  
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public class FileSplitterFetch extends Thread { |r6<DEg
 

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String sURL; //File URL z$S)|6Q  
long nStartPos; //File Snippet Start Position F~&bg
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long nEndPos; //File Snippet End Position v=@Z,-  
int nThreadID; //Thread's ID !,|yrB&`S  
boolean bDownOver = false; //Downing is over -2bu`oD `  
boolean bStop = false; //Stop identical \_0nH`  
FileAccessI fileAccessI = null; //File Access interface >u~ l_?  
U^:+J-z{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException b,~6cDU  
{ S9U`-\L0  
this.sURL = sURL; \M<C6m5  
this.nStartPos = nStart; Uz[#t1*  
this.nEndPos = nEnd; 3)p#}_u{  
nThreadID = id; 0c /xE<h  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 z-ra]  
} ):kDWc  
K-Y;[+#g1o  

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public void run() yC(xi"!  
{ DTH;d-Z  
while(nStartPos < nEndPos && !bStop) +?DP r  
{ #px74EeI\  
!^:b?M  
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try{ 9jBP|I{xI  
URL url = new URL(sURL); sZx
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); au1uFu-  
httpConnection.setRequestProperty("User-Agent","NetFox"); U\s.fIr  
String sProperty = "bytes="+nStartPos+"-"; lpvZ[^G  
httpConnection.setRequestProperty("RANGE",sProperty); Gx,<|v  
Utility.log(sProperty); *S%~0=  
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InputStream input = httpConnection.getInputStream(); U9[QdC  
//logResponseHead(httpConnection); z.P<)[LUc  
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byte[] b = new byte[1024]; CC"}aV5  
int nRead; KxhMPvN'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Kg4\:A7Sa.  
{ |KY6IGcqV  
nStartPos += fileAccessI.write(b,0,nRead); o"wvP~H  
//if(nThreadID == 1) !8~A
`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EX@wenR  
} ~}Xd{afo  
wIeF(}VM  
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Utility.log("Thread " + nThreadID + " is over!"); ||yx?q6\h  
bDownOver = true; !p #m?|Km  
//nPos = fileAccessI.write (b,0,nRead); .6C9N{?Tqf  
} )d(F]uV:y  
catch(Exception e){e.printStackTrace ();} lZ gX{  
} q#D-}R_RN  
} 6Uh_&?\%  
[L(qrAQ2|z  
#w]UP#^io  
//打印回应的头信息 )IBvm1  
public void logResponseHead(HttpURLConnection con) KJ (|skO  
{ Q%>6u@'  
for(int i=1;;i++) }ZqnsLu[)  
{ l;7T.2J'Z  
String header=con.getHeaderFieldKey(i); FT8<a }o  
if(header!=null) 7up~8e$_  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <DR$WsDG  
Utility.log(header+" : "+con.getHeaderField(header)); Z; 6N7U  
else U\y:\+e l  
break; s$g3_
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} S/
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} E|_J  
t4d^DZDh!  
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public void splitterStop() SL[EOz#  
{ eL" +_lW  
bStop = true; z&wJ"[nOC  
} D/)E[Fv+  
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(l+0*o,(  
} n:"0mWnL$y  
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/* g|Tkl  
**FileAccess.java u u$Jwn!S  
*//文件访问(定位，写) O>y*u8  
package NetFox; [Smqe>U1  
import java.io.*; +v+Dkyf:V  
oL U!x
 
}IRD!  
public class FileAccessI implements Serializable{ ]P*H,&I`#  
lJ Jn@A  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |mQC-=6t;Y  
RandomAccessFile oSavedFile; ntxaFVD  
long nPos; P"{yV?CNg  
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public FileAccessI() throws IOException bfq%.<W  
{ Q_6v3no1  
this("",0); }SFmv},Ij  
} o&$Of  
,7Dm p7  
#Xk/<It  
public FileAccessI(String sName,long nPos) throws IOException f5z*AeI  
{ soOfk!b  
oSavedFile = new RandomAccessFile(sName,"rw"); 2WS Wfh  
this.nPos = nPos; G0u H6x?  
oSavedFile.seek(nPos); 5mX"0a_Q  
} QL\3|'a  
p4uN+D`.U  
CG ,H  
public synchronized int write(byte[] b,int nStart,int nLen) A;TNR  
{ uHuL9Q^  
int n = -1; Am<){&XT ]  
try{ W[LQ$uj  
oSavedFile.write(b,nStart,nLen); 'soll[J  
n = nLen; 19bqz )  
} _xM}*_<VP  
catch(IOException e) !KtP> `8  
{ YRu/KUT$ 7  
e.printStackTrace (); zG7y$\A  
} WM0-F@_  
je74As[  
sWq@E6,I  
return n; /tJ%gF  
} G%dzJpC(  
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} V8G.KA "  
c3)6{  
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/* w x,gth*p  
**SiteInfoBean.java M y!;N1  
*/ =.IAd<C  
package NetFox; au+a7~0~  
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public class SiteInfoBean {
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?:7.3{|Aq  
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private String sSiteURL; //Site's URL yG<Q t+D  
private String sFilePath; //Saved File's Path RaA7 U   
private String sFileName; //Saved File's Name <%"CQT6g%  
private int nSplitter; //Count of Splited Downloading File FXbalQ?^  
h@{CMe
 
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public SiteInfoBean() +2m\Sv V  
{//nSplitter的缺省值为5 N#^o,/  
//default value of nSplitter is 5 O/ZyWT  
this("","","",5); 960rbxKy3  
} 2*Mu"v,  
(y?`|=G-xT  
|EFbT>  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *KPNWY9!W  
{ eSSv8[u  
sSiteURL= sURL; {&h=  
sFilePath = sPath; Tl*FK?)MC^  
sFileName = sName; $u{ 8wF/)  
this.nSplitter = nSpiltter; "0{t~?ol  
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} lLZ?&z$  
`BY&&Bv#?  
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public String getSSiteURL() xJ)vfo  
{ ,IG?(CK|  
return sSiteURL; fYgX|#Me  
} 1{bsh?zd  
/ Hexv#3  
#VM-\02o  
public void setSSiteURL(String value) xkkW?[&  
{ /qO?)p3gk  
sSiteURL = value; g}
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} fQ~YBFhlr  
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public String getSFilePath() -W XZOdUjs  
{ 2bt2h.a  
return sFilePath; RLX?3u&  
} u6BLhyS  
X&({`Uw<K  
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public void setSFilePath(String value) "K-2y^Dl  
{ ue#Yh  
sFilePath = value; $5a%hK  
} [lX3":)  
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gDjs:]/YR  
public String getSFileName() 9% AL f 9  
{ ^ql+l~  
return sFileName; b<mxf\b  
} o%\p
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OA3* "d*  
public void setSFileName(String value) Xm}~u?$3  
{ 9K5[a^q|My  
sFileName = value; v(2|n}qY  
} DEkFmmw   
f*^)
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, *A',  
public int getNSplitter() *eo<5YUHt  
{ %8lF%uu!x  
return nSplitter; Y l1sAf/  
} -O-qEQd  
xl~%hw
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public void setNSplitter(int nCount) PME ?{%&  
{ .OC{,f+  
nSplitter = nCount; ^#VyIF3q  
} uZ(j"y  
} __,1;=  
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/* #}rv)  
**Utility.java Q@-7{3  
*/ c~+;P(>  
package NetFox; U,4:yc,)s  
a}+7MEUmZ/  
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public class Utility { Cq,ox'kGl  
YdK]%%  
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public Utility() zi*2>5g  
{ `2@t) :  
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} [fU2$(mT+  
)MKzAAt~  
//线程睡眠 tGs=08`  
public static void sleep(int nSecond) \=yx~c_$L  
{ \HB4ikl  
try{ ;O2r
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Thread.sleep(nSecond); |?!Ew# w  
} Q-!a;/  
catch(Exception e) 4u zyU_  
{ uwl;(zwh_  
e.printStackTrace (); G2%%$7Jj  
} rI5)w_E?  
} DM*mOT  
I4Ys,n  
//日志 j6~#_t[  
public static void log(String sMsg) ]&3UF?  
{ x-5XOqD{'  
System.err.println(sMsg); f-?00*T  
} M<,E[2op  
D 5qCn^R  
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public static void log(int sMsg) s wdW70  
{ ,?+rM ;  
System.err.println(sMsg); "mnWqRpX  
} F(8>"(C  
} dE+xU(\,w  
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8}0W_CU,  
/* l("Dw8H  
**TestMethod.java )j40hrR  
*/ r`|/qP:T[  
package NetFox; vnXa4\Vdy  
JBCcR,\kM*  
.VVY]>bJg@  
public class TestMethod { {ZH9W
 
Y" s1z<?  
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public TestMethod() -i@1sNx&'  
{ ///xx/weblogic60b2_win.exe 0)V<)"i  
try{ `?Yh`P0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ldo7}<s  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); iNR6BP W  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5uK:f\y)l  
fileFetch.start(); vMXS%Q  
} %v\0Dm+A  
catch(Exception e){e.printStackTrace ();} ;%Jw9G\h  
|\j'Z0  
j(!M  
} 2B7X~t>8a  
w<*tbq  
>_1*/o JO  
public static void main(String[] args) zxtx~XO  
{ 2;G^>BP<  
new TestMethod(); \+E{8&TH'  
} bIP{DxKS  
} 8?4j-  
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