http断点续传简单实现（java)

/* !Qjpj KRy  
**SiteFileFetch.java e'(n ^_$nl  
*/ f[.RAHjk  
package NetFox; pZ+zm6\$  
import java.io.*; %>Z=#1h/a  
import java.net.*; NS-u,5Jt  
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public class SiteFileFetch extends Thread { 2W|4
 
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SiteInfoBean siteInfoBean = null; //文件信息Bean s2_j@k?%  
long[] nStartPos; //开始位置 /#20`;~F)  
long[] nEndPos; //结束位置 5|NM]8^^0[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 l Vo](#W  
long nFileLength; //文件长度 ]o$Kh$~5  
boolean bFirst = true; //是否第一次取文件 5dT-{c%w4  
boolean bStop = false; //停止标志 LTS3[=AB  
File tmpFile; //文件下载的临时信息 ] $$ciFM  
DataOutputStream output; //输出到文件的输出流 -WE pBt7*  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） #l2wF>0  
public SiteFileFetch(SiteInfoBean bean) throws IOException x
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{ [ hm/B`t*e  
siteInfoBean = bean; `(H]aTLt ,  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); VaJX,
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); s) u{A  
if(tmpFile.exists ()) k<ku5U1|
 
{ s!nFc{  
bFirst = false; /$\yAOA'y  
read_nPos(); I|m fr{  
} %<O'\&!,  
else 7.CzS  
{ {3yzC  
nStartPos = new long[bean.getNSplitter()]; pwT|T;j*  
nEndPos = new long[bean.getNSplitter()]; >wej1#\3  
} k`Ab*M$@Xs  
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} YTL [z:k}  
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public void run() {G&K_~Vj  
{ Tcz67&c |W  
//获得文件长度 uZz^>*b  
//分割文件 Z$X2*k6PK  
//实例FileSplitterFetch 37?%xQ!  
//启动FileSplitterFetch线程 ?T7`E q  
//等待子线程返回 Lx8^V7X  
try{ L:%ek3SOz  
if(bFirst) PQWo<Uet  
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nFileLength = getFileSize(); &sR{3pC}  
if(nFileLength == -1) 7`6n]4e  
{ J^hj R%H  
System.err.println("File Length is not known!"); S-gL]r3G8  
} ?#ndMv!$  
else if(nFileLength == -2) ZL#4X*zT  
{ \s`'3y  
System.err.println("File is not access!"); G2ZF`WQ  
} %N|7<n<S  
else }%| (G[  
{ yb*SD!  
for(int i=0;i<nStartPos.length;i++) 7 '2E-#^  
{ 0h^upB#p  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); w?Nvm?_]  
} W>wIcUP<<  
for(int i=0;i<nEndPos.length-1;i++) cm%QV?  
{ t&mw@bj  
nEndPos = nStartPos[i+1]; Z7JI4"  
} +NxEx/{  
nEndPos[nEndPos.length-1] = nFileLength; ?%{bMqYJD{  
} igOjlg_Q  
} L

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//启动子线程 .oO_x>  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; =9i:R!,W  
for(int i=0;i<nStartPos.length;i++) x/~V ZO  
{ 1oFU4+{ 4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B*zb0hdo:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), IJD'0/R'c  
nStartPos,nEndPos,i); Axk p  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nrUrMnlg  
fileSplitterFetch.start(); 9^4^EY#  
} 58mzh
82+  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KG'4;Z5J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .Ig`v  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", zY(w`Hm2  
nEndPos = " + nFileLength); t.j q]L  
// fileSplitterFetch[nPos.length-1].start(); )Y\},O  
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J}i$ny_3OB  
//等待子线程结束 rxI?|}4  
//int count = 0; ;pU9ov4)  
//是否结束while循环 x(hUQu 6  
boolean breakWhile = false; Wgq*|teW  
"}\z7^.W>  
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while(!bStop) pA!+;Y!ZB<  
{ |5F]y"Nb  
write_nPos(); []1VD#  
Utility.sleep(500); rD%(*|Y"c  
breakWhile = true; CP7Zin1S/w  
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for(int i=0;i<nStartPos.length;i++) 5[al^'y  
{ /6gqpzum4  
if(!fileSplitterFetch.bDownOver) )KaQ\WJ:  
{ Zu$f-_"  
breakWhile = false; /!eC;qp;[  
break; {3$ge  
} C&NoEtL>s  
} ?)",}XL6  
if(breakWhile) R{8nR00|1  
break; 3`n5[RV  
3+{hO@O  
WWrDr   
//count++; !!o69  
//if(count>4) 5A7!Xd  
// siteStop(); |42E'zH&  
} u&STGc[  
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6@wnF>'/\  
System.err.println("文件下载结束！"); 6.Ef
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} )UI T'*ow  
catch(Exception e){e.printStackTrace ();} UrH^T;#  
} *B)>5r  
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//获得文件长度 w/d9S(  
public long getFileSize() X~P0Q  
{ [k@D}p x  
int nFileLength = -1; @gE +T37x2  
try{ ok-sm~bp  
URL url = new URL(siteInfoBean.getSSiteURL()); n4>
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >`5iq.v  
httpConnection.setRequestProperty("User-Agent","NetFox"); n2Dnpe:  
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int responseCode=httpConnection.getResponseCode(); }}cVPB7  
if(responseCode>=400) BtBy.bR  
{ fk*JoR.o  
processErrorCode(responseCode); >f'nl  
return -2; //-2 represent access is error ^-~.L: }q  
} .Ky<9h.K  
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String sHeader; qnrf%rS  
O*H:CW  
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for(int i=1;;i++) }UXj|SY  
{ x@v,qF$K  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); WB6g i2  
//Utility.log(in.readLine()); KT{<iz_  
sHeader=httpConnection.getHeaderFieldKey(i); RNRMw;cT  
if(sHeader!=null) E0ud<'3<  
{ /B|#GJ\\3  
if(sHeader.equals("Content-Length")) #
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{ QMy;?,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *ErTDy(   
break; aZ*b"3  
} ~<Gs<c}z  
} 9s73mu`Twg  
else 6M"J3\ x  
break; dvyE._/v  
} u\^<V)  
} Iy8gQdI  
catch(IOException e){e.printStackTrace ();} K?-K<3]9f  
catch(Exception e){e.printStackTrace ();} 45/f}kvy
 
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c*~/[:}  
Utility.log(nFileLength); 7R7g$  
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return nFileLength; lH:TE=|4  
} Z:O24{ro
5  
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//保存下载信息（文件指针位置） 6}C4 SZ  
private void write_nPos() U+@yx>!  
{ 8Dhq_R'r  
try{ eJ'2CM6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Jc`LUJT  
output.writeInt(nStartPos.length); Ip.5I!h[Xb  
for(int i=0;i<nStartPos.length;i++) Q`5jEtu#,  
{ *: e^yi  
// output.writeLong(nPos); |oSyyDYWP  
output.writeLong(fileSplitterFetch.nStartPos); FLEf(  
output.writeLong(fileSplitterFetch.nEndPos); :/~`"`#1  
} Haj`mc!<D0  
output.close(); >bz}IcZP  
} IJS9%m#  
catch(IOException e){e.printStackTrace ();} }`5%2iG  
catch(Exception e){e.printStackTrace ();} fAUtqkB  
} "uTzmm$  
.}SW`RPk  
fhMtnh:  
//读取保存的下载信息（文件指针位置） Bq79Ev .-  
private void read_nPos() p
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{ %?X~,  
try{ zJ|Ek"R.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1kb?y4xeJ  
int nCount = input.readInt(); nHD4J;l  
nStartPos = new long[nCount]; F
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nEndPos = new long[nCount]; pA(@gisg  
for(int i=0;i<nStartPos.length;i++) *Z|!%C  
{ <G2;nvRr  
nStartPos = input.readLong(); 3t68cdFlz  
nEndPos = input.readLong(); 2~R"3c+^  
} Z(/jQ=ozQ  
input.close(); vB/MnEKR  
} R/ l1$}  
catch(IOException e){e.printStackTrace ();} ouVR[w>V  
catch(Exception e){e.printStackTrace ();} kn+`2-0  
} jl3RE|M\<  
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private void processErrorCode(int nErrorCode) 9y.C])(2  
{ C<qJnB:B9  
System.err.println("Error Code : " + nErrorCode); h(GgkTj4+  
} ],qG!,V  
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//停止文件下载 j\@s pbE@  
public void siteStop() iknBc-TLD  
{ )3h=V^rm  
bStop = true; Q&`$:h.~  
for(int i=0;i<nStartPos.length;i++) LtejLCf/  
fileSplitterFetch.splitterStop(); f IQ$a>  
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} p*#SSR9<  
} [7|}h/  
//负责部分文件的抓取 =]-!  
**FileSplitterFetch.java c!{.BgGN  
*/ pR`.8MMc8  
package NetFox; F~W*"i+EZ  
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2#T|+mKxZM  
import java.io.*; Zp- Av8  
import java.net.*; r{>tTJFD(:  
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public class FileSplitterFetch extends Thread { &Vnet7LfU  
k5g\s9n]  
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String sURL; //File URL `j_R ?mY  
long nStartPos; //File Snippet Start Position <| Xf4.  
long nEndPos; //File Snippet End Position $'?CY)h{  
int nThreadID; //Thread's ID jpm}EOq<%  
boolean bDownOver = false; //Downing is over VaVKWJg$  
boolean bStop = false; //Stop identical L!mQP  
FileAccessI fileAccessI = null; //File Access interface akJ{-   
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1m}'Y@I  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException F4kU) i  
{ &rcr])jg[  
this.sURL = sURL; W 86S)+h  
this.nStartPos = nStart; 'qQDM_+  
this.nEndPos = nEnd; !
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nThreadID = id; ?D57HCd`n  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 \m5:~,p=  
} <C# s0UX  
1PLKcU  
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public void run() jqb,^T|j;m  
{ Zu&trxnNf[  
while(nStartPos < nEndPos && !bStop) xhg{!w  
{ d@,q6R}!MP  
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9dqD(S#C;"  
try{ 2=F_<Jh|+  
URL url = new URL(sURL); I?bL4u$\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %b@>riR(y  
httpConnection.setRequestProperty("User-Agent","NetFox"); LO#{  
String sProperty = "bytes="+nStartPos+"-"; rLh490
@  
httpConnection.setRequestProperty("RANGE",sProperty); ,_\h)R_  
Utility.log(sProperty); <0v'IHlZ8  
.N/4+[2p(  
/~gM,*  
InputStream input = httpConnection.getInputStream(); R;I}#b cJ  
//logResponseHead(httpConnection); 6<rc]T'|  
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iLv"ZqGrw  
byte[] b = new byte[1024]; ^4 es  
int nRead; 5>h2WL  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) pA+Qb.z5z  
{ -lb}}z+/  
nStartPos += fileAccessI.write(b,0,nRead); X903;&Cim  
//if(nThreadID == 1) _I5p 7X  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ' nf"u  
} .(1=iL_3e  
<C${1FO7If  
?G!
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Utility.log("Thread " + nThreadID + " is over!"); nez5z:7F  
bDownOver = true; g.F{yX]  
//nPos = fileAccessI.write (b,0,nRead); F^A1'J  
} +/x|P-  
catch(Exception e){e.printStackTrace ();} ~X`vRSrH  
} f4!
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} #'$CC<*vy  
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r)U9u 0  
//打印回应的头信息 pxDZ}4mOh  
public void logResponseHead(HttpURLConnection con) &(Xp_3PO  
{ \Cx3^ iX  
for(int i=1;;i++) ->8n
.!F}  
{ Jv7
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String header=con.getHeaderFieldKey(i); El"XF?OgpP  
if(header!=null) DU}q4u@)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !X[lNtO  
Utility.log(header+" : "+con.getHeaderField(header)); IO v4Zx<)  
else p)TH^87  
break; 'y'>0'et  
} Eptsxyz{  
} ,aawtdt/  
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public void splitterStop() 3bE^[V8/  
{ VMHiuBz:  
bStop = true;  $JX_e  
} %,6@Uu#%6  
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} QbOmJQ  
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/* 3 5|5|ma  
**FileAccess.java *dUnP{6g  
*//文件访问(定位，写) DrMcE31  
package NetFox; w :^b3@gd  
import java.io.*; [DjdR_9*I  
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{ 
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public class FileAccessI implements Serializable{ Kpj0IfC,10  
d*q_DV  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 y6:=2(]w<p  
RandomAccessFile oSavedFile; `@Kh>K  
long nPos; {/#?n["  
atl0#FBd  
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public FileAccessI() throws IOException ;'=!Fv  
{ K}
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this("",0); {yspNyOx  
} /\#
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public FileAccessI(String sName,long nPos) throws IOException S1`+r0Fk~n  
{ 2"V?+Hhz  
oSavedFile = new RandomAccessFile(sName,"rw"); yDy3;*lE  
this.nPos = nPos; /xf%Rp4}  
oSavedFile.seek(nPos); QM;L>e-ZY  
} vQBfT% &Q-  
WdIr3  
sVh!5fby&  
public synchronized int write(byte[] b,int nStart,int nLen) kFuaLEJi  
{ gI\J sN  
int n = -1; 3+n&Ya1  
try{ 3R4-MK  
oSavedFile.write(b,nStart,nLen); n%"s_W'E  
n = nLen; ,`-6!|:  
} ~rn82an@G  
catch(IOException e) )G*Hl^Z;4  
{ eJ7A.O  
e.printStackTrace (); 3n6_
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} *h-nI=  
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return n; UN,@K9  
} !7 *X{D v  
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} `<\AnhNW]I  
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eeB^c/k(P  
/* .&}}ro48
  
**SiteInfoBean.java sfVtYIu  
*/ 8 wC3}U  
package NetFox; pN%L3?2  
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]u2!)vZh'  
public class SiteInfoBean { (A(d]l  
 D&N5)   
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private String sSiteURL; //Site's URL nC[L"%E|se  
private String sFilePath; //Saved File's Path zL)m!
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private String sFileName; //Saved File's Name trgj]|?M  
private int nSplitter; //Count of Splited Downloading File DSET!F;PG  
Kw-E%7gh4c  
^5"s3Qn  
public SiteInfoBean() W@pVP4F0xM  
{//nSplitter的缺省值为5 2/>AmVM  
//default value of nSplitter is 5 ,v)@&1Wh:  
this("","","",5); .sjM$#V=  
} 4[+n;OI  
]S%qfna e1  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) CS6,mX  
{ =b !f  
sSiteURL= sURL; 5:56l>0  
sFilePath = sPath; #
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sFileName = sName; ]j_S2lt  
this.nSplitter = nSpiltter; hc~--[1c:  
Hh54&YKZ  
m0un=>{  
} 6!b96bV  
6,s@>8n  
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public String getSSiteURL() gpE5ua&  
{ xN2{Vi{ad  
return sSiteURL; $IB@|n  
} f]o DZO%^  
9e8@0?0  
oa;[[2c  
public void setSSiteURL(String value) wf8vKl#Kfw  
{ -+ $u  
sSiteURL = value; w 7=Y_  
} 37M7bB0  
QGLfZvTT  
&o:ZOD.  
public String getSFilePath() / ^!(rHf  
{ 4[bw/[
  
return sFilePath; m6'YFpf)V  
} "L{;=-e  
oPre$YT}h  
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public void setSFilePath(String value) "kf7??Z  
{ m,*t}j0 7  
sFilePath = value; 1Pn!{ bU3@  
} ;~/  
o+6Y/6Xp@  
1VJE+3  
public String getSFileName() ,n&Dg58K  
{ G7zfyw}W  
return sFileName; C"hc.A&4  
} gKS^
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tTQ>pg1{qh  
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public void setSFileName(String value) 3tOnALv  
{ QE-t v00  
sFileName = value; l2n>Wce9  
} I>ofSaN  
8
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b4,yLVi<T  
public int getNSplitter() tEf-BV;\y  
{ 2R|2yAh  
return nSplitter; 0/-[k  
} R,6?1Z:J  
EeL~`$f  
!~>u\h  
public void setNSplitter(int nCount) :Wb+&|dU  
{ EY> %#0  
nSplitter = nCount; kiqq_`66  
} .F%RW8=Q  
} :@YZ6?hf  
i,b>&V/Y$  
#(XP=PUj  
/* 3MkF  
**Utility.java ?i9LqHL  
*/ zb:p,T@5  
package NetFox; @GjWeOj]  
p/SJt0  
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public class Utility { Yckl,g_  
srg#<oH|{c  
~#(bX]+A  
public Utility() 5n?fZ?6(  
{ 6;5}% B:#h  
xr.fZMOh4  
}bjTb!  
} .5_w^4`b  
7\5 [lM  
//线程睡眠 Pu}r` E_  
public static void sleep(int nSecond) #!Kg?BR2  
{ b
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try{ Uv5E$Y"e10  
Thread.sleep(nSecond); O:k@'&  
} ]6}|X#_  
catch(Exception e) F<G.!Y8!&  
{ z[CCgs&vqe  
e.printStackTrace (); `[CXxp  
} /UM9g+Bb  
} W}JJaZR*X  
njvmf*A?S  
//日志 wGb{O  
public static void log(String sMsg) %Z.>)R4  
{ udW, P  
System.err.println(sMsg); ?XW+&!ar  
} 3}Uae#oy  
HLTz|P0JZ  
2Ni2Gkf@  
public static void log(int sMsg) =}_c=z?UY  
{ *i)GoQoB  
System.err.println(sMsg); &bA;>Lu#|o  
} [(UQQa=+  
} uw;s](~E  
H^'EY:|  
tAYu|\]  
/* fZXd<Fg+  
**TestMethod.java [=..#y!U  
*/ N[
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package NetFox; ygT,I+7\  
/m9t2,KB  
PvKe|In(  
public class TestMethod { TC J\@|yw  
.6  
,!bOzth2>K  
public TestMethod() iTxn  
{ ///xx/weblogic60b2_win.exe =:9n+7~$  
try{ ;jI\MZ~l\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); M.H4ud  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,>"1'i&@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); *4=Fy:R]O  
fileFetch.start(); Vv6xVX  
} 4}#*M2wb  
catch(Exception e){e.printStackTrace ();} J& yDX>  
}]tSWVb*  
{s_0[>  
} b!_l(2  
dp_J*8  
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public static void main(String[] args) WMl_$Fd6  
{ $c  f?`k  
new TestMethod(); ^3AJYu  
} -/7[_,  
} Tcr&{S&o  
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