http断点续传简单实现（java)

/* D#S\!>m  
**SiteFileFetch.java >yJ9U,Y  
*/ dz>;<&2Z  
package NetFox; a}SdW  
import java.io.*; PA w-6;  
import java.net.*; _7DkS}NJs  
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~ d^<_R  
public class SiteFileFetch extends Thread { ;6 +}z~  
6n1rL  
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SiteInfoBean siteInfoBean = null; //文件信息Bean {G*A.$-d  
long[] nStartPos; //开始位置 ceGa([#!\_  
long[] nEndPos; //结束位置 PCnQ_A-Q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 PM":Vd/  
long nFileLength; //文件长度 )6~1 ^tD  
boolean bFirst = true; //是否第一次取文件 ;IK[Y{W/  
boolean bStop = false; //停止标志 Jx#k,Z4  
File tmpFile; //文件下载的临时信息 v+"rZ  
DataOutputStream output; //输出到文件的输出流 H UoyLy  
!6&W,0<  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） `MP|Ovns:H  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,@z4I0cTi\  
{ 4(l?uU$  
siteInfoBean = bean; -yDs< Xl  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .k4W_9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `bKA+c,f  
if(tmpFile.exists ()) e4OeoQ@ >  
{ _ .i3,-l)  
bFirst = false; ;d$qc<2uA  
read_nPos(); xyr+_k-x&q  
} (wmBjQ]B<  
else $N2SfyX7  
{ hC_Vts[v/  
nStartPos = new long[bean.getNSplitter()]; ,%bhyww<  
nEndPos = new long[bean.getNSplitter()]; A~nf#(!^]  
} 56hA]O29O  
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} W\f9jfD  
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public void run() 0^'
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{ 0i[zup
 
//获得文件长度 R6 XuA(5  
//分割文件 =rPrPb  
//实例FileSplitterFetch Kt>X3m,  
//启动FileSplitterFetch线程 @&1Wyp  
//等待子线程返回 6pE :A@  
try{ ^0W(hA  
if(bFirst) 52zGJ I*  
{ zm9TvoC%}  
nFileLength = getFileSize(); BcA31%  
if(nFileLength == -1) +5v}q.:+  
{ #$vRJ#S}U  
System.err.println("File Length is not known!"); &@"]+33  
} ?B.~AUN  
else if(nFileLength == -2) G)>W'yxQ  
{ }2)DPP:ic  
System.err.println("File is not access!"); 5sde  
} h06ku2Q  
else =R*Gk4<Y  
{ v;y0jD
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for(int i=0;i<nStartPos.length;i++) xa( m5P  
{ V@=V5bZLs  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); %,b X/!  
} &Y@#g9G  
for(int i=0;i<nEndPos.length-1;i++) yj@tV2  
{ M4Z@O3OIE  
nEndPos = nStartPos[i+1]; !}3,B28  
} P,gdnV ^  
nEndPos[nEndPos.length-1] = nFileLength; 151tXSzLT  
} "fQRk  
} x2|6
  
c.H?4j7ga  
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//启动子线程 RK9>dk
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fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |P6EO22p  
for(int i=0;i<nStartPos.length;i++) I.}1JJF*  
{ _baYn`tFw-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s_jBu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]Gc3Ea;4  
nStartPos,nEndPos,i); g(0;[#@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P2n2Qt2  
fileSplitterFetch.start(); MrE<vw@he  
} Ni[4OR$-O  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UkR3}{i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A,~Hl
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )Du-_Z  
nEndPos = " + nFileLength); 
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// fileSplitterFetch[nPos.length-1].start(); ST1Ts5I  
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//等待子线程结束 w5]"ga>Y  
//int count = 0; QF-)^`N  
//是否结束while循环 .BTx&AqU  
boolean breakWhile = false; !jS4!2'  
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v@ONo?)  
while(!bStop) {j(4m  
{ X7aXxPCq1  
write_nPos(); 6(56,i<#/  
Utility.sleep(500); & %}/AoU  
breakWhile = true; TW`mxj_J2  
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for(int i=0;i<nStartPos.length;i++) x;$|#]+  
{ <Mgf]v.QS  
if(!fileSplitterFetch.bDownOver) ~] =?b)B  
{ yYAnwf  
breakWhile = false; s*,cF6  
break; ?)A2Kw>2  
} `]2@_wa  
} d5xxb _oE  
if(breakWhile) y[HQBv  
break; *)VAaGUX>  
;?9A(q_Z  
7#4%\f+'t  
//count++; "!&B4  
//if(count>4) ;cSGlE
|  
// siteStop(); MUof=EJg>u  
} +}!DP~y+  
ZW ye>]  
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System.err.println("文件下载结束！"); %= u/3b:o  
} Rlg#z4m  
catch(Exception e){e.printStackTrace ();} j)D-BK&+  
} okBE|g  
gn5% F5W  
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//获得文件长度 |1V2tx  
public long getFileSize() X7cWgo66T  
{ *8!w&ME+.  
int nFileLength = -1; [%.18FWI  
try{ Gj6. Iv  
URL url = new URL(siteInfoBean.getSSiteURL()); 2:J,2=%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nTZ> |R)  
httpConnection.setRequestProperty("User-Agent","NetFox"); S!j^|!  
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int responseCode=httpConnection.getResponseCode(); N^$9;CKP=  
if(responseCode>=400) !P|5#.eC  
{ 2,AaP*,  
processErrorCode(responseCode); D3?N
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return -2; //-2 represent access is error Qyj(L[KJ  
} |QYZRz  
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String sHeader; ^@_).:oX7  
_^;;i4VZ  
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for(int i=1;;i++) O_CT+Ou  
{ x}"Q8kD  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >~&(P_<b  
//Utility.log(in.readLine()); LP>UU ,Z  
sHeader=httpConnection.getHeaderFieldKey(i); EhXiv#CZ  
if(sHeader!=null) e{t=>vry  
{ nYov>x]  
if(sHeader.equals("Content-Length")) [_%,6e+  
{ T'R,vxP)\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); zUQe0Gc.b^  
break; ]C)|+`XE@  
} t-lv|%+8
 
} :Y.e[@!1x  
else vXubY@k2  
break; 1l]C5P}E  
} A9n41,h  
} 4Iq5+Q  
catch(IOException e){e.printStackTrace ();} VG\
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catch(Exception e){e.printStackTrace ();} " Z;uu)NE  
" dT>KQ  
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Utility.log(nFileLength); 5DSuUEvWcL  
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&|z|SY]DL  
return nFileLength; _?Ckq
 
} )OUU]MUH  
c
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//保存下载信息（文件指针位置） b]K>vhQV  
private void write_nPos() WY.
5K =}  
{ #7C6
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try{ V2QW\2@$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); JX&~y.F  
output.writeInt(nStartPos.length); CXa Ld7nMX  
for(int i=0;i<nStartPos.length;i++) Oo/8Y E
@  
{ cKpQr7]ur  
// output.writeLong(nPos); AY@k-4  
output.writeLong(fileSplitterFetch.nStartPos); 5Jd` ^U  
output.writeLong(fileSplitterFetch.nEndPos); kd`YSkZ  
} EP0a1.C  
output.close(); OequU'j  
} C M^r|4K  
catch(IOException e){e.printStackTrace ();} >Qk97we'9  
catch(Exception e){e.printStackTrace ();} ER2V*,n@  
} ~,G]glu8  
?
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9F)W19i.  
//读取保存的下载信息（文件指针位置） h/9Sg*k  
private void read_nPos() zi_[V@Es/  
{ }JGq
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try{ %Y 2G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); C,3T!\  
int nCount = input.readInt();
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nStartPos = new long[nCount]; Hi7G/2t@`  
nEndPos = new long[nCount];
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for(int i=0;i<nStartPos.length;i++) lux9o$ %  
{ ]]3Q*bq4  
nStartPos = input.readLong(); q!@c_o  
nEndPos = input.readLong(); DzE E:&*=  
} sOC| B  
input.close(); p Mh++H]"  
} )=Y-f?o!  
catch(IOException e){e.printStackTrace ();} G "c/a8  
catch(Exception e){e.printStackTrace ();} R{ 4u|A?9  
} T#/11M$uQ  
g!\QIv1D  
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private void processErrorCode(int nErrorCode) $4:~*IQ  
{
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System.err.println("Error Code : " + nErrorCode); ]Qc: Zy3  
} ',%5mF3j  
b2W;|  
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//停止文件下载 G*=H;Upi  
public void siteStop() 4(;20(q]  
{ 8m \;P  
bStop = true; #-A5Z;TD.  
for(int i=0;i<nStartPos.length;i++) E8 \\X  
fileSplitterFetch.splitterStop(); Yr:>icz|  
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%K`4k.gN  
} 'oT|cmlc  
} 8@Q"YA3d+  
//负责部分文件的抓取 7V |"~%  
**FileSplitterFetch.java o`25  
*/ np= J:v4  
package NetFox; %"{?[!C ?  
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import java.io.*; }el,^~  
import java.net.*; ?!rU |D  
z[%[bs2{  
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public class FileSplitterFetch extends Thread { EyzY2>"^  
}
&=uZ:  
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String sURL; //File URL &KLvr|  
long nStartPos; //File Snippet Start Position W0+u)gDDz  
long nEndPos; //File Snippet End Position +I?Qg  
int nThreadID; //Thread's ID \?[O,A  
boolean bDownOver = false; //Downing is over Jr|K>  
boolean bStop = false; //Stop identical YALyZ.d  
FileAccessI fileAccessI = null; //File Access interface +)% ,G@-`  
_%XbxP6rH  
&C\=!r0j^  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;%M2x5  
{ [+yGDMLs  
this.sURL = sURL; ,C
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this.nStartPos = nStart; x!Y(Y=i>  
this.nEndPos = nEnd; wbo{JQ  
nThreadID = id; F1zT )wW  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 % 1OC#&  
} hwc:@'  
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]Pz|Oi+]  
public void run() 5Gc_LI&v7  
{ oXvdR(Sb^  
while(nStartPos < nEndPos && !bStop) ik8|9m4/  
{ 3{6ps : w  
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try{ Au~+Zz|mQ  
URL url = new URL(sURL); A3m{jbh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wA{*W>i  
httpConnection.setRequestProperty("User-Agent","NetFox"); LNWqgIq  
String sProperty = "bytes="+nStartPos+"-"; {H/8#y4qp&  
httpConnection.setRequestProperty("RANGE",sProperty); I=Gr^\x=  
Utility.log(sProperty); "tEj`eR  
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InputStream input = httpConnection.getInputStream(); ':5Trx  
//logResponseHead(httpConnection); xn0s`I[  
't||F1X~J  
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byte[] b = new byte[1024]; ,ZsYXW  
int nRead; 7g{g}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &h98.A*&  
{ MHC.k=  
nStartPos += fileAccessI.write(b,0,nRead); |k/`WC6As.  
//if(nThreadID == 1) }x{rTEq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); GG@iKLV  
} Cb4d|yiS8  
L{4),65  
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Utility.log("Thread " + nThreadID + " is over!"); {ILp[&sL  
bDownOver = true; V.O<|tl.  
//nPos = fileAccessI.write (b,0,nRead); "it`X B.  
} UwvGr h  
catch(Exception e){e.printStackTrace ();} *##QXyyg  
} *C[4 (DmB  
} ez{P-
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#RCZA4>  
//打印回应的头信息 gPF}aaB
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public void logResponseHead(HttpURLConnection con) U^vUdM"  
{ tg4LE?nv
 
for(int i=1;;i++) V'Sd[*  
{ t?pIE cl  
String header=con.getHeaderFieldKey(i); B<vvsp\X  
if(header!=null) !Qj)tS#Az  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &;SwLDF"1  
Utility.log(header+" : "+con.getHeaderField(header)); ]<&
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else s{x*~M$vt  
break; cij]&$;Q  
} K|P9uHD  
} uK+9gTv  
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public void splitterStop() \}]=?}(  
{ 9&|12x$  
bStop = true; wdN>KS2!  
}
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} SXT@& @E  
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^VM"!O;h{  
/* Mm:a+T  
**FileAccess.java TsFV ;Sl3  
*//文件访问(定位，写) kx;xO>dC  
package NetFox; B` t6H  
import java.io.*; 8gu'dG=  
02]8|B(E90  
bv:0EdVr  
public class FileAccessI implements Serializable{ n',9#I(!L  
jWO&SWso  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 )D6'k{6M  
RandomAccessFile oSavedFile; sp=7Kh?|>  
long nPos; u`L!za7fi  
V{a}#J  
!.tL"U~4  
public FileAccessI() throws IOException &"~,V6,q  
{ [FeJ8P>z  
this("",0); mlsvP%[f.  
} vkNZ -`+I  
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public FileAccessI(String sName,long nPos) throws IOException 6I5[^fv45G  
{ )Ta]6  
oSavedFile = new RandomAccessFile(sName,"rw"); YKs^%GO+  
this.nPos = nPos; \pBYWf  
oSavedFile.seek(nPos); @@&@}IQcR1  
} j:de}!wc  
&\WkJ}&PnA  
n{qa]3  
public synchronized int write(byte[] b,int nStart,int nLen) "R\\\I7u  
{ ^Yf)lV&[  
int n = -1; dctA`W@:-  
try{ ~,M;+T}[r  
oSavedFile.write(b,nStart,nLen); Kc-A-P &Ry  
n = nLen; o%N0K  
} 
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catch(IOException e) R"8})a gw  
{ ^,ZvKA"}+/  
e.printStackTrace (); ya*q;D  
} btB(n<G2#  
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return n; >g
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} VQG /g\  
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} 4/mj"PBKL  
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/* Xx9~  
**SiteInfoBean.java C7fi1~  
*/ !kHyLEV  
package NetFox; ,pGCgOG#}c  
u1pYlu9IW  
VW<"c 5|  
public class SiteInfoBean { NZw[.s>n  
J~yd]L>  
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private String sSiteURL; //Site's URL HpjIp.  
private String sFilePath; //Saved File's Path 40l#'< y;  
private String sFileName; //Saved File's Name [jtj~]&mO  
private int nSplitter; //Count of Splited Downloading File 5 a*'N~  
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public SiteInfoBean() Jj^<:t5{rN  
{//nSplitter的缺省值为5 4{;8 ]/.a  
//default value of nSplitter is 5 H$qdU!c  
this("","","",5); _>:=<xyOq  
} }mT%N eS  
:BZx)HxQ  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (1r>50Ge  
{ ,[K)E  
sSiteURL= sURL; n9-q5X^e>  
sFilePath = sPath; 2YP"nj#  
sFileName = sName; @T~#Gwv  
this.nSplitter = nSpiltter; 7gR;  
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o._#=7|(  
} qeO6}A"^|  
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public String getSSiteURL() h+'eFAZ  
{ $xn%i\  
return sSiteURL; (=&bo p  
} J/P@m_Yx  
+EB,7<5<  
1-Wnc'(OK  
public void setSSiteURL(String value) DGuUI}|)  
{ EA@$^e[  
sSiteURL = value; GzZ|T7fm  
} (Ss77~W7  
f!R^;'a  
f6_|dvY3  
public String getSFilePath() bEXHB  
{ I>4Tbwy.-  
return sFilePath; F+m4  
} Xy8ie:D  
@v-)|8GdY  
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public void setSFilePath(String value) m=y,_Pz>U  
{ $^+K
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sFilePath = value; z?) RF[  
} *$Wx*Jo  
&u`rE""  
#?|1~HC  
public String getSFileName() @aPu}Hi  
{ n~>CE"q  
return sFileName; ~aq?Kk  
} 2] wf`9ZH  
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g}og@UY7#  
public void setSFileName(String value)  IOES3  
{ g#<?OFl  
sFileName = value; = ]HJa
 
} ZzaW@6LJF  
' ^L  
hw.demD  
public int getNSplitter() E?5B>Jer#  
{
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return nSplitter; wTAEJ{p  
} xp;8p94   
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public void setNSplitter(int nCount) B46H@]d#7K  
{ =d4',[O  
nSplitter = nCount; }6{)Jv  
} 5}^08Xl  
} !rmo*-=^=  
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/* R#^pNJN  
**Utility.java $A0]v!P~i-  
*/ yT9RNo/w  
package NetFox; GN"LU
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public class Utility { Y%cA2V\#m  
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public Utility() l8Iy03H  
{ 7(iRz  
hQLx"R$  
E0%Y%PQ**{  
} jl%eO.  
?BZ`mrH^  
//线程睡眠 X1QZEl  
public static void sleep(int nSecond) k#G7`dJl  
{ (dnc7KrM  
try{ K]Cs2IpI  
Thread.sleep(nSecond); 3\~fe/z'I  
} 3T^dgWXEG  
catch(Exception e) >N"PLSY1  
{ MBrVh6z>  
e.printStackTrace (); pY5HW2TsY|  
} @uD{`@[  
} $>37PVVW  
l]=$<  
//日志 EF{'J8AQ  
public static void log(String sMsg) <g1hdF0  
{ /'^>-!8_1  
System.err.println(sMsg); tl
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} 6y!?xot  
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gx R|S  
public static void log(int sMsg) W 9MZ  
{ m&c(N  
System.err.println(sMsg); Olh-(u:9+O  
} mK&9p{4#U  
} 6HQwL\r79  
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/* J
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**TestMethod.java A{"t0Ai='0  
*/ 9 9BK/>R  
package NetFox; q)y8Bv|  
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n 9M6wS  
public class TestMethod { VQ}3r)ch  
l:}4 6%  
euC,]n.  
public TestMethod() ee[NZz  
{ ///xx/weblogic60b2_win.exe Pt;Ahmi  
try{ RIx6& 7$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); iFchD\E*o  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); '0rwNEg  
SiteFileFetch fileFetch = new SiteFileFetch(bean); -{mq\GvGn  
fileFetch.start(); nit7|T@^  
} +>({pHZ<S  
catch(Exception e){e.printStackTrace ();} !Hj)S](F  
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} ="E V@H?U  
(ZsR=:9(  
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public static void main(String[] args) a$&6a   
{ o:*i
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new TestMethod(); ixpG[8s  
} Lxrn#Z eM  
} 2 -8:qmP(  
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