http断点续传简单实现（java)

/* (SW6?5  
**SiteFileFetch.java #3_g8ni5X  
*/ 9VTAs:0D=  
package NetFox; EQ^]W-gN  
import java.io.*; R$l- 7YSt  
import java.net.*; bFN/{^SB  
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public class SiteFileFetch extends Thread { )N- '~<N  
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!?ZR_=Y%  
SiteInfoBean siteInfoBean = null; //文件信息Bean ?+d{Rh)y  
long[] nStartPos; //开始位置 >i  
long[] nEndPos; //结束位置 3]kM&lK5\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 deYv&=SPl  
long nFileLength; //文件长度 AC <2.i_  
boolean bFirst = true; //是否第一次取文件 7NT} Zwf  
boolean bStop = false; //停止标志 9jf9u0  
File tmpFile; //文件下载的临时信息 _PPC?k{z!  
DataOutputStream output; //输出到文件的输出流 I^f|U
 
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &S+*1<|`K  
public SiteFileFetch(SiteInfoBean bean) throws IOException D1-w>Y#  
{ pm=O.)g4`  
siteInfoBean = bean; R2~y<^.V`Y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5>%^"f  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); U`3?bhzua  
if(tmpFile.exists ()) 6|q"lS*$S  
{ 6p)&}m9!  
bFirst = false; Peph..8Z  
read_nPos(); y>t:flD*  
} `T+>E0H(f  
else ;rT/gwg!  
{ >H;m[  
nStartPos = new long[bean.getNSplitter()]; tx[;& ;  
nEndPos = new long[bean.getNSplitter()]; 7Dssr [  
} bf.+Ewb(  
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} (@*|[wN  
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public void run() <Ez@cZ"  
{ 0$`pYW]  
//获得文件长度 ku*k+4rz  
//分割文件 qk'&:A  
//实例FileSplitterFetch {ST8'hY  
//启动FileSplitterFetch线程 ZMMx)}hS  
//等待子线程返回 A3 TR'BFw-  
try{ 0B9FPpx?:  
if(bFirst) Ji,;ri2
i  
{ nT=%3_.
 
nFileLength = getFileSize(); X4:84  
if(nFileLength == -1) jbe:"Stw  
{ P]^8Enp
 
System.err.println("File Length is not known!"); B0yGr\KJ  
} 1t/c@YUTy  
else if(nFileLength == -2) XN t` 4$L  
{ y_[VhZ%  
System.err.println("File is not access!"); ={cM6F}a@  
} cu5}(  
else (T2HUmkQ6  
{ '=+N )O  
for(int i=0;i<nStartPos.length;i++) fFbJE]jW  
{ P]}:E+E<.I  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 11QZ- ^  
} S9l po_!z  
for(int i=0;i<nEndPos.length-1;i++) oq|o"n)~  
{ \2El>>  
nEndPos = nStartPos[i+1]; rC|nE=i  
} Ag:/iB]  
nEndPos[nEndPos.length-1] = nFileLength; AX+]Z$  
} _Fj\0S"  
} AX{<d@z`j  
rT;l#<#VE  
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//启动子线程 V]Ccj\Oi  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; w-)JCdS6Tb  
for(int i=0;i<nStartPos.length;i++) {-7ovH?  
{
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), VWdTnu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Tg@G-6u0c  
nStartPos,nEndPos,i); d=+zOF  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YSB> WBS-<  
fileSplitterFetch.start(); 9({ 9r[U  
} t4;gY298  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ={o4lFe3v(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); KMb
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;dZZOocV1  
nEndPos = " + nFileLength); )2W7>
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// fileSplitterFetch[nPos.length-1].start(); z<A8S=s6n  
8%4v6No&*  
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//等待子线程结束 aW|=|K  
//int count = 0; |uFb(kL[U  
//是否结束while循环 l#ct;KZ  
boolean breakWhile = false; J Z@sk2  
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SLkgIb~'X  
while(!bStop) bSI*`Dc"!  
{ ueW/i  
write_nPos(); e]!`94f  
Utility.sleep(500); wDiq~!  
breakWhile = true; obbg#,  
SI6?b1;-:F  
m|?1HCRXRI  
for(int i=0;i<nStartPos.length;i++) h8M}}   
{ yP-$@Ry  
if(!fileSplitterFetch.bDownOver) .aWwJZ=[  
{ &u"mFweS  
breakWhile = false; $@{d\@U  
break; &?@U_emLi  
} fRk'\jzT  
} Wkb>JnPo  
if(breakWhile) ~9!@BL\  
break; DD7D&@As  
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//count++; e5FF'~A%]  
//if(count>4) s;Zi   
// siteStop(); ):=8w.yC  
} fK@UlMC]7  
2WKIO|'  
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System.err.println("文件下载结束！"); rwwyYIlEg  
} 'R$/Qt;uA  
catch(Exception e){e.printStackTrace ();} [UdJ(cGf  
} A;/,</  
H,/=<Th;i  
rWM5&M  
//获得文件长度 *6_>/!ywI  
public long getFileSize() {RsdI=%  
{ rf^IJY[  
int nFileLength = -1; Bq4@I_b  
try{ #cD$ DA  
URL url = new URL(siteInfoBean.getSSiteURL()); IA=\c  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =y?Aeqq\fl  
httpConnection.setRequestProperty("User-Agent","NetFox"); p*zTuB~e<  
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int responseCode=httpConnection.getResponseCode(); NQ '|M  
if(responseCode>=400) 
}D
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{ |t$%kpp  
processErrorCode(responseCode); [8DPZU@  
return -2; //-2 represent access is error 0"sZP\<p  
} 54]UfmT%I  
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[e|9%[.V  
String sHeader; %&'[? LXD  
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for(int i=1;;i++) 0|\A5 eG  
{ nGJ+.z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); c; 1f$$>b  
//Utility.log(in.readLine()); 'vZWkeo  
sHeader=httpConnection.getHeaderFieldKey(i); [w FK!?  
if(sHeader!=null) !a%_A^t7  
{ ZS&+<kGD  
if(sHeader.equals("Content-Length")) .q 4FGPWz  
{ (G>g0(;D-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); j->5%y  
break; (r.y   
} -ebyW#  
} O+DYh=m*p  
else T}'*Gry  
break; d<cQYI4V  
} `apC
u  
} i|!R*"  
catch(IOException e){e.printStackTrace ();} BQgK<_  
catch(Exception e){e.printStackTrace ();} M;.:YkrUH  
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Utility.log(nFileLength); |t58n{V.O  
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(x[z=_I%`  
return nFileLength; )4GCL(&  
} QcdAg%"yy  
)\izL]=!t  
eN TKX  
//保存下载信息（文件指针位置） _^0UK|[  
private void write_nPos() }f6_7W%5  
{ *@ S+J$  
try{
P>]*pD  
output = new DataOutputStream(new FileOutputStream(tmpFile)); I<&)P#"  
output.writeInt(nStartPos.length); @Rqn&tA8  
for(int i=0;i<nStartPos.length;i++) =#I/x=
L:  
{ &x[V<
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// output.writeLong(nPos); :{#w-oC>6P  
output.writeLong(fileSplitterFetch.nStartPos); 9$R}GK  
output.writeLong(fileSplitterFetch.nEndPos); )*BG-nM u  
} Uo:=-NNI  
output.close(); CY@#_z  
} -zm-|6[Wi  
catch(IOException e){e.printStackTrace ();} \-Q
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catch(Exception e){e.printStackTrace ();} NF*Z<$'%  
} 40;4=  
<q4<3A  
baR*4{]  
//读取保存的下载信息（文件指针位置） ?*f2P T?`  
private void read_nPos() ,V+,3TT  
{ j;&su=p"  
try{ RDu{U(!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |198A,^  
int nCount = input.readInt(); bqZ5GKUo  
nStartPos = new long[nCount]; [_tBv" z  
nEndPos = new long[nCount]; mw${3j
~&  
for(int i=0;i<nStartPos.length;i++) N*}g+IS  
{ H7Ee0T(`  
nStartPos = input.readLong(); Yc>.P  
nEndPos = input.readLong(); `Y<FR  
} 5&Le?-/\  
input.close(); >Cglhsb:N  
} #<R6!"TNoz  
catch(IOException e){e.printStackTrace ();} @aWd0e]  
catch(Exception e){e.printStackTrace ();} HUGhz  
} h}GzQry1  
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private void processErrorCode(int nErrorCode) I^gLiLUN*6  
{ 2Ni
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System.err.println("Error Code : " + nErrorCode); gp]T.ol  
} &>Nw>V  
|#O>DdKHT
 
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//停止文件下载 zhC5%R &n/  
public void siteStop() K!|J/W  
{ =D^R,Q  
bStop = true; _VLA2#V>  
for(int i=0;i<nStartPos.length;i++) !='L`.  
fileSplitterFetch.splitterStop(); ^" UZ.@sq'  
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} 5}'W8gV?  
} Nb/Z+  
//负责部分文件的抓取 vqJq=\ .m  
**FileSplitterFetch.java ~|8-Mo1ce  
*/ .arWbTR)~U  
package NetFox; sK|+&BC
 
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import java.io.*; ^qNr<Ye  
import java.net.*; c[4I> "w  
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public class FileSplitterFetch extends Thread {  D
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WKONK;U+7  
}Gh95HwE  
String sURL; //File URL -h,?_d>  
long nStartPos; //File Snippet Start Position Y/,Cy0!  
long nEndPos; //File Snippet End Position !TPKD  
int nThreadID; //Thread's ID ee .,D  
boolean bDownOver = false; //Downing is over 2$yNryd  
boolean bStop = false; //Stop identical LCemM;o  
FileAccessI fileAccessI = null; //File Access interface y3@5~4+  
_ v3VUm#  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =$F<Ac;&  
{ 8@d@T V!n&  
this.sURL = sURL; 2X@"#wIg  
this.nStartPos = nStart; Hie  
this.nEndPos = nEnd; R2f^dt^  
nThreadID = id; sH+ 90|?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (cm8x  
} EVDcj,b"^  
lWk/vj<5  
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public void run() !4(QeV-=  
{ %@Nu{?I  
while(nStartPos < nEndPos && !bStop) <4%vl+qW  
{ .%+y_.l  
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try{  ]YKxJ''u  
URL url = new URL(sURL); FZ=xy[q]~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `E8D5'tt  
httpConnection.setRequestProperty("User-Agent","NetFox"); e3]v *<bj  
String sProperty = "bytes="+nStartPos+"-"; d2X?^  
httpConnection.setRequestProperty("RANGE",sProperty); `]wk)50BVp  
Utility.log(sProperty); tk!5"`9N  
J)="Im)  
}5lC8{wZ  
InputStream input = httpConnection.getInputStream(); p?'&P!  
//logResponseHead(httpConnection); x5eSPF1  
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byte[] b = new byte[1024]; ~Nn}FNe  
int nRead; O#x=iZI  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) OzUo}QN  
{ ;><m[l6  
nStartPos += fileAccessI.write(b,0,nRead); aQglA  
//if(nThreadID == 1) s-JS[  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); WSOz^]  
} jAy0k   
X v$"B-j  
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Utility.log("Thread " + nThreadID + " is over!"); ZFRKzPc {V  
bDownOver = true; X \qG WpN%  
//nPos = fileAccessI.write (b,0,nRead); g,s^qW0vds  
} <j:@ iP  
catch(Exception e){e.printStackTrace ();} Z^_gS&nDa~  
} Y
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} 40HhMTZ0-  
].Xh=7&2{  
1EA#c>I$  
//打印回应的头信息 d
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public void logResponseHead(HttpURLConnection con) 3U%kf<m=  
{ U}DLzn|w  
for(int i=1;;i++) J(w 3A)(  
{ :r9<wbr)k0  
String header=con.getHeaderFieldKey(i); t"jiLO
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if(header!=null) D4$2'h  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /o9 0O&  
Utility.log(header+" : "+con.getHeaderField(header)); [Z;ei1l  
else O9_SVX
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break; 7R$O~R3p  
} sq;3qbz  
} -mLS\TFS  
#M@~8dAH}M  
5Kw?#  
public void splitterStop() ~{-9qOGw;  
{ U;t1 K  
bStop = true; w$"^)EG,7  
} nB6 $*'  
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} "D'"uMS`H  
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8yk4#CZ  
/* L5r02VzbD
 
**FileAccess.java XvVi)`8!u  
*//文件访问(定位，写) +`uNO<$~f  
package NetFox; =:'\wx X  
import java.io.*; k{D0
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public class FileAccessI implements Serializable{ 06]"{2  

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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 z! :0%qu  
RandomAccessFile oSavedFile; WV}HN  
long nPos; Sg*+!  
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CV)K=Br5&_  
public FileAccessI() throws IOException a9NIK/9  
{ "EwzuM8f  
this("",0); 8J:=@X^}  
} R5&<\RI0  
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Hb0_QT~  
public FileAccessI(String sName,long nPos) throws IOException aNP\Q23D  
{ d|>/eb.R  
oSavedFile = new RandomAccessFile(sName,"rw"); 2}15FXgN  
this.nPos = nPos; '3?-o|v@D  
oSavedFile.seek(nPos); nf1O8FwRb  
} wV-9T*QrM  
<!F".9c@A  
#n]K$k>  
public synchronized int write(byte[] b,int nStart,int nLen) oxL)Jx\c9A  
{ [}yPy))A  
int n = -1; }46Zfg\T6n  
try{ }{)Rnb@ >  
oSavedFile.write(b,nStart,nLen); {.ypZ8JU  
n = nLen; (__$YQ-  
} {vdY(  
catch(IOException e) \&47u1B  
{ $gZiW8  
e.printStackTrace (); =\G`g#  
} )!~,xl^j{}  
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WyRSy-{U(}  
return n; H!'4A&  
} mZO-^ct4  
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} rdCs  
>Y(JC#M;  
NF
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/* z/fSstN  
**SiteInfoBean.java }B_?7+  
*/ 70 Ph^e)  
package NetFox; r6GXmr  
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public class SiteInfoBean { Lp/'-Y_  
!{fu(E  
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private String sSiteURL; //Site's URL T}
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private String sFilePath; //Saved File's Path q"EW*k+ )  
private String sFileName; //Saved File's Name e N v\ZR1  
private int nSplitter; //Count of Splited Downloading File O p1TsRm5L  
Uz~B`  
Kwi+}B!  
public SiteInfoBean() <@[;IX`YN  
{//nSplitter的缺省值为5 (V1;`sI8  
//default value of nSplitter is 5 w 62m}5eA  
this("","","",5); [XttT  
} 8!YQ9T[  
'n=bQ"bQu  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }ice*3'3  
{ B!&y>Z^$  
sSiteURL= sURL; K1o>>388G  
sFilePath = sPath; r+h%a~A#>  
sFileName = sName; `NsQ&G  
this.nSplitter = nSpiltter; !&:
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?8/r=  
;K~=? k  
} }zxf~41  
P&=YLL<W  
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public String getSSiteURL() Zb2PFwcy  
{ Bex;!1  
return sSiteURL; 0U:X[2|)  
} %|ClYr  
pL!,1D!  
<$K=3&:s8q  
public void setSSiteURL(String value) !3iZa*  
{ #d*0 )w  
sSiteURL = value; RyU8{-q  
} 5*+DN U@  
'J3yJ{  
7VG*Wu  
public String getSFilePath() -agB ]j  
{ _>n)HG  
return sFilePath; yf!7 Q>_G^  
} A FBH(ms't  
P3-O)m]jv  
mZc;n.$U  
public void setSFilePath(String value) _|W&tB*  
{ ?iV}U  
sFilePath = value; m mZP;  
} 'wtb"0 }  
{&XTa`C  
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public String getSFileName() )+|wrK:*v  
{ M$.bC0}T  
return sFileName; S>r}3,]S  
} YtKT3u:x  
]f?r@U'AS|  
7)[2Ud8  
public void setSFileName(String value) uF1 4;  
{ UJQTArf  
sFileName = value; 6rj iZ%  
} }st~$JsV1  
.AOc$Nt  
mtkZF{3Jx  
public int getNSplitter() M$Ui=GGq  
{ ]kx<aQ^  
return nSplitter; ']fyD3N  
} S.Kcb=;"L  
j,;f#+O`g  
J%|;  
public void setNSplitter(int nCount) )/JVp>  
{ 8t=O=l\  
nSplitter = nCount; /4O
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}  B9y5NX  
} FyWf`XTO  
}yn%_KQ0  
gK;dfrU.8Y  
/* qoH:_o8ClO  
**Utility.java kTfRm^  
*/ X@}7 #Vt  
package NetFox; -?:8sv*X  
1Az&BZU[  
qTRP2rH,L&  
public class Utility { Pv,PS.,-  
j>?nL~{  
:RukW.MR  
public Utility() lK7:qo  
{ pfIK9>i  
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A'7Y{oPHX  
} $H.U ~  
{fDRVnI?  
//线程睡眠 \p(
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public static void sleep(int nSecond) BeQ'\#q,  
{ -zMvpe-am&  
try{ $*$4DG1gaR  
Thread.sleep(nSecond); &Ep$<kx8  
} 1 oKY7i$  
catch(Exception e) H7P}=YW".  
{ )quQI)Ym  
e.printStackTrace (); HJJ)DE7;  
} :UH*Wft1  
} m<z?6VC  
^GrSvl}v'  
//日志 K$D+TI)  
public static void log(String sMsg) >T
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{ ROfV Y:,M  
System.err.println(sMsg);
.#Z'CZO|  
} ZL0k  
^_3$f  
0YL*)=pD,  
public static void log(int sMsg) yx&}bu\  
{ 87
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System.err.println(sMsg); Q.7X3A8  
} z1,#ma}.  
} m(:R(K(je  
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~N| aCi-X  
/* bA Yp }  
**TestMethod.java CdCY#$Z  
*/ +}(]7du  
package NetFox; |x1Ttr,  
R+He6c!?9  
@oj_E0i3  
public class TestMethod { F?MVQ!K*  
%La/E#  
`|"o\Bg<  
public TestMethod() SJO*g&duQ  
{ ///xx/weblogic60b2_win.exe z=>PjIW  
try{ >k@{N
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C"`\[F`.k  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); il{x?#Wrb  
SiteFileFetch fileFetch = new SiteFileFetch(bean); /8`9SS  
fileFetch.start(); @>~S$nw/  
} UHi^7jQ  
catch(Exception e){e.printStackTrace ();} P|?nx"c  
E=S_1  
sA: /!9  
} i=>`=. ~  
tRc3<>  
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public static void main(String[] args) u 1}dHMoX~  
{ ZJGIib  
new TestMethod(); S\sy^Kt~4:  
} y|*4XF<b  
} ho~WD'i  
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