http断点续传简单实现（java)

/* ~;TV74~rr  
**SiteFileFetch.java ADTU{6UPS  
*/ W;5N04ko  
package NetFox; TjT](?'o  
import java.io.*; Yo>%s4_,  
import java.net.*; DCz\TwzU  
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public class SiteFileFetch extends Thread { z/pDOP Ku  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ;.L!%$0i#  
long[] nStartPos; //开始位置 `Uu^I   
long[] nEndPos; //结束位置 69N1 mP  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )0'Y et}  
long nFileLength; //文件长度 >h|UCJ1 `  
boolean bFirst = true; //是否第一次取文件 HE9. k.sS  
boolean bStop = false; //停止标志 "MW55OWYU  
File tmpFile; //文件下载的临时信息 kVy"+ZebK  
DataOutputStream output; //输出到文件的输出流 >>/nuWdpO  
1a \=0=[  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） M_yZR^;^-  
public SiteFileFetch(SiteInfoBean bean) throws IOException oC5gME"2  
{ N45s'rF  
siteInfoBean = bean; OX'/?B((  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); hU |LFjc  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }o~Tw?z-|  
if(tmpFile.exists ()) ,^Ex}Z  
{ ))c*_n  
bFirst = false; bBd*}"v^"  
read_nPos(); RJQ/y3  
} >:="?'N5l!  
else g]:..W7  
{ o,iS&U"TC  
nStartPos = new long[bean.getNSplitter()]; 4&#vU(-H  
nEndPos = new long[bean.getNSplitter()]; r7zf+a]  
} $[WN[J  
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} }S Y`KoC1  
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public void run() e,PQ)1  
{ %w;1*~bH  
//获得文件长度 ch%Q'DR_I)  
//分割文件 0:~gW#lD  
//实例FileSplitterFetch J+-,^8)  
//启动FileSplitterFetch线程 #u!y`lek  
//等待子线程返回 @Z"QA!OK~c  
try{ w;yar=n  
if(bFirst) :/n ?4K^  
{ 0tn7Rkiw  
nFileLength = getFileSize(); :FEd:0TS  
if(nFileLength == -1) Lqy|DJ%  
{ 1',+&2)oj  
System.err.println("File Length is not known!"); k i~Raa/e  
} FZ;YvdX6  
else if(nFileLength == -2) uOy\{5s8  
{ }s8*QfK>  
System.err.println("File is not access!"); EfMG(oI  
} H{p[Ghp  
else U`},)$  
{ ',v0vyO8  
for(int i=0;i<nStartPos.length;i++) h9@gs,'   
{ s2,`eV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Py(wT%w
 
} sIP6GWK$  
for(int i=0;i<nEndPos.length-1;i++) D| 3AjzW  
{ ?
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nEndPos = nStartPos[i+1]; $\=6."R5<  
} w+:+r/!g  
nEndPos[nEndPos.length-1] = nFileLength; #)IdJ]  
} YB(#]H|8S  
} L>|A6S#y8/  
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//启动子线程 4jI*Y6Wkz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |qFN~!  
for(int i=0;i<nStartPos.length;i++) 476M` gA  
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pJ<)intcbE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), KV3+}k  
nStartPos,nEndPos,i); 2l;ge>DJ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >xk:pL*o`  
fileSplitterFetch.start(); oQE_?">w  
} 3M5=@Fwkr  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  Wl}G[>P  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `pn-fk  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ixUiXP  
nEndPos = " + nFileLength); QQ2OZy>W  
// fileSplitterFetch[nPos.length-1].start(); #EwRb<'Em  
l-JKcsM  
6r?cpJV{  
//等待子线程结束 ?j ;,q  
//int count = 0; OmQuAG ^\x  
//是否结束while循环 [K^q:3R  
boolean breakWhile = false; B@:XC&R^  
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while(!bStop) xfZ9&g  
{ J^e|"0d  
write_nPos(); S a#d?:L  
Utility.sleep(500); /-cX(z 7  
breakWhile = true; A*?/F:E  
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for(int i=0;i<nStartPos.length;i++) wHDFTIDI  
{ vFkyfX(   
if(!fileSplitterFetch.bDownOver) mSqk[Ig\  
{ _@}MGWlAPt  
breakWhile = false; <CdG[Ih  
break; RaJ}>e  
} L>K39z~,  
} n$Oky-P"  
if(breakWhile) ^~hhdwu3a  
break; {yl/T:Bh&  
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//count++; 7xa@wa?!L  
//if(count>4) >H]|A<9u(  
// siteStop(); Q{)F$]w  
} CuGOjQ-k~  
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System.err.println("文件下载结束！"); ps4Wwk(  
} B[k+#YYY  
catch(Exception e){e.printStackTrace ();} LxYM"_1A;  
} /R+]}Lt~%*  
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//获得文件长度 _yXeX  
public long getFileSize() &t@6qi`d  
{ 8aIq#v  
int nFileLength = -1; t,as{.H{h  
try{ M,dzf   
URL url = new URL(siteInfoBean.getSSiteURL()); d1LTyzLr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r5$?4t  
httpConnection.setRequestProperty("User-Agent","NetFox"); /A`zy  
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int responseCode=httpConnection.getResponseCode(); APOU&Wd  
if(responseCode>=400) \Q BpgMi(  
{ g{f>jd  
processErrorCode(responseCode); 6d?2{_},  
return -2; //-2 represent access is error Z6 |'k:R8  
} ]9l%  
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String sHeader; PX>\j&  
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for(int i=1;;i++) R<YYf^y  
{ '%r@D&*vp  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8 H"f9S=K  
//Utility.log(in.readLine()); "/]tFY%Y  
sHeader=httpConnection.getHeaderFieldKey(i); \(v
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if(sHeader!=null) ucm.~1G(  
{ s%?p%2&RA  
if(sHeader.equals("Content-Length")) jnLo[Cf,H8  
{ Bjrv;)XH  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); l
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break; oVZ8p-  
} @nW(KF  
} ~k<31 ez  
else E)Epr&9S  
break; )-:f;#xJ  
} g5YsVp  
} *
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catch(IOException e){e.printStackTrace ();} q\Io6=39x  
catch(Exception e){e.printStackTrace ();} d+| !6  
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Utility.log(nFileLength); b.u8w2(  
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return nFileLength; k=/|?%  
} 4I[FE;^  
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 `:  
//保存下载信息（文件指针位置） g"AfI  
private void write_nPos() blkJm9]v  
{ ^+l\YB7pD  
try{ m.g@S30  
output = new DataOutputStream(new FileOutputStream(tmpFile)); vpw&"?T
 
output.writeInt(nStartPos.length); +W3>Yg%)X  
for(int i=0;i<nStartPos.length;i++) 5x'y{S<  
{ 9%k.GE  
// output.writeLong(nPos); v\tbf  
output.writeLong(fileSplitterFetch.nStartPos); 7 QJcRZ[lU  
output.writeLong(fileSplitterFetch.nEndPos); :^L]Da3  
} SG o:FG  
output.close(); @tp7tB ;  
} 8`?j*FV7kq  
catch(IOException e){e.printStackTrace ();} u! FSXX<  
catch(Exception e){e.printStackTrace ();} )h!l%7
2  
} Yt<PKs#E  
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//读取保存的下载信息（文件指针位置） 9@a;1Wr/f  
private void read_nPos() ~O7(0RsCN  
{ ]6[d-$#^ko  
try{ w+(wvNmNEK  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); NjyIwo0  
int nCount = input.readInt(); <;Z3 5{  
nStartPos = new long[nCount]; (#"s!!b  
nEndPos = new long[nCount]; m8A_P:MQq  
for(int i=0;i<nStartPos.length;i++) aw~EK0yU   
{ ZvKMRW  
nStartPos = input.readLong(); /'_ RI  
nEndPos = input.readLong(); /6*.%M>r  
}
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input.close(); ^<Tp-,J$EN  
} s;M*5|-  
catch(IOException e){e.printStackTrace ();} {mitF  
catch(Exception e){e.printStackTrace ();} BfLZ  
} qiryC7.E  
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private void processErrorCode(int nErrorCode) =8D4:Ds  
{ k0uwG'(z9  
System.err.println("Error Code : " + nErrorCode); N9|.D.#MF  
} ABDUp:  
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//停止文件下载 BT#g?=n#`  
public void siteStop() }f'1x%RS^  
{ j}*+-.YF  
bStop = true; <~*Ol+/  
for(int i=0;i<nStartPos.length;i++) j7+t@DqQ  
fileSplitterFetch.splitterStop(); dkp[?f)x  
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} p>
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} X1dG'PQ  
//负责部分文件的抓取 GP'Y!cl  
**FileSplitterFetch.java kweTK]mT  
*/ 6x{IY  
package NetFox; Y\|J1I,Z4  
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import java.io.*; -y.AJ~T  
import java.net.*; ~{Bi{aK2  
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public class FileSplitterFetch extends Thread { wO%:WL$5  
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String sURL; //File URL R!qrb26k  
long nStartPos; //File Snippet Start Position (W!$6+GT  
long nEndPos; //File Snippet End Position [0#hgGO]P  
int nThreadID; //Thread's ID mhuaXbr  
boolean bDownOver = false; //Downing is over ;VRR=p%,  
boolean bStop = false; //Stop identical 5^/[]*  
FileAccessI fileAccessI = null; //File Access interface mIo7 K5z{  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0z#kV}wE  
{ 9-6_:N>
 
this.sURL = sURL; -"H4brj;G  
this.nStartPos = nStart; D:EF@il  
this.nEndPos = nEnd; N|S xAg  
nThreadID = id; L|w-s4L  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 _AbEQ\P{  
} ! fc)  
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public void run() ii9/ UtIQ  
{ ,+9r/}K]/  
while(nStartPos < nEndPos && !bStop)  gVkI=J  
{ uJ[Vv4N%9  
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try{ 0&@pX~h:  
URL url = new URL(sURL); c<e\JJY5?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $twF93u$  
httpConnection.setRequestProperty("User-Agent","NetFox"); I!D*(>  
String sProperty = "bytes="+nStartPos+"-"; J7vpCw2ni  
httpConnection.setRequestProperty("RANGE",sProperty); ,ua1xsZl&  
Utility.log(sProperty); 7`!( 8  
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InputStream input = httpConnection.getInputStream(); ,[L$  
//logResponseHead(httpConnection); 1}*;  
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byte[] b = new byte[1024]; q(Q9FonU  
int nRead; 1bkUT_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) T@.D5[q0:  
{ "mK (?U!A  
nStartPos += fileAccessI.write(b,0,nRead); SI5QdX  
//if(nThreadID == 1) 7!;/w;C  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^i\1c-/  
} 09s}@C  
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/vu!5?S  
Utility.log("Thread " + nThreadID + " is over!"); RiG!TTa b  
bDownOver = true; p]=;t
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//nPos = fileAccessI.write (b,0,nRead); w}q"y+=Z:  
} =:eE!  
catch(Exception e){e.printStackTrace ();} z?[DW*  
} k)Wz b  
} F DX+  
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Iq\oB  
//打印回应的头信息 >~~\==".  
public void logResponseHead(HttpURLConnection con) mM>|fHGA  
{ 4V8wB}y7e  
for(int i=1;;i++) pr(\?\a  
{ taaAwTtk?A  
String header=con.getHeaderFieldKey(i); DU8LU*q'  
if(header!=null) S '+"+%^tj  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |pSoBA9U  
Utility.log(header+" : "+con.getHeaderField(header)); IoOnS)  
else GJPZ[bo  
break; qCN7i&k,  
} BxYA[#fd}  
} Xm'K6JH'  
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public void splitterStop() IxBO$2  
{ n4y6Ua9m{  
bStop = true; U:hC!t:  
} " SqKS,J  
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} zAJ
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/* `wd*&vl  
**FileAccess.java W[<":NX2  
*//文件访问(定位，写) C
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package NetFox; o1+]6s+j}  
import java.io.*; ~1sl.8tF  
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public class FileAccessI implements Serializable{ q.{/{9  
'fFdqsXr  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +Q0-jS#d  
RandomAccessFile oSavedFile; S'p`ECfVMA  
long nPos; KB
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public FileAccessI() throws IOException @$Kq<P  
{ o{W]mr3D  
this("",0); ,s&~U<Z  
} FH`&C*/F0Y  
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public FileAccessI(String sName,long nPos) throws IOException j)6B^!  
{ '$-,;vnP0  
oSavedFile = new RandomAccessFile(sName,"rw"); pY#EXZ#   
this.nPos = nPos; % ul{nL:  
oSavedFile.seek(nPos); z}&C(m:al  
} BM~niW;k  
^T6!z^g1h  
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public synchronized int write(byte[] b,int nStart,int nLen) chzR4"WZFt  
{ D-:<]D:  
int n = -1; 0.+eF }'H  
try{ 5THS5'
  
oSavedFile.write(b,nStart,nLen); Am0C|(#Xm  
n = nLen; q*TKs#3  
} Ab<Ok\e5  
catch(IOException e) [j U  
{ lILtxVBO2o  
e.printStackTrace (); F>(#Af9  
} BG0Mj2  
v/.h%6n?  
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return n; bMOM`At>z  
} |hQ|'VCN  
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} ^6y4!='ci  
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/* ai  _fN  
**SiteInfoBean.java 15o *r  
*/ ,Ysl$^\  
package NetFox; ,T*_mDVY  
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public class SiteInfoBean { @EOR]^?!]  
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private String sSiteURL; //Site's URL -<JBKPtA  
private String sFilePath; //Saved File's Path b\j&!_   
private String sFileName; //Saved File's Name L(2P|{C  
private int nSplitter; //Count of Splited Downloading File VN-#R=D  
aevG<|qP  
3]OP9!\6  
public SiteInfoBean() bNpIC/#0K  
{//nSplitter的缺省值为5 'L|GClc6)
 
//default value of nSplitter is 5 4S0++Hp
4  
this("","","",5); ^@*zH?Rx{  
} RR"WO  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \M"^Oe{Dy?  
{ X>Xp&o  
sSiteURL= sURL;  QXxLe*  
sFilePath = sPath; jvc?hUcLKT  
sFileName = sName; '}pgUh_  
this.nSplitter = nSpiltter; 0"qim0%|DF  
G1;'nwf}  
) UDJ[pL@  
} avt>saR  
~{,vg4L  
<
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public String getSSiteURL() j_'rhEdLP  
{ @f5@0A\0  
return sSiteURL; :&0yf;>v  
} :{i$2\DH6  
bqQO E4;  
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public void setSSiteURL(String value) @Gn?8Ur%  
{ 7?!Z+r  
sSiteURL = value; -Xxu/U})%  
} <\d|=>;  
$,e?X}4  
)y/DGSd  
public String getSFilePath() f{^M.G@  
{ k#Ez  
return sFilePath; <K#'3&*$s  
} f5yux}A{  
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/#qs(! d  
public void setSFilePath(String value) <f.>jjwFE  
{ s\Pt,I@Y_  
sFilePath = value; Tc
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} `zzKD2y  
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public String getSFileName() a?,[w'7FU  
{ Y=:KM~2hv  
return sFileName; o!=lBfI  
} "0H56#eW  
^?s~Fk_V  
~C"k$;(n  
public void setSFileName(String value) N$,/Q9h^  
{ ;N$
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sFileName = value; &8Jg9#  
} 9o`7Kc/g  
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};"+ O  
public int getNSplitter() 'Uko^R)(  
{ zD)IU_GWa  
return nSplitter; 2B9i R  
} ovDJ{3L6O  
t8DL9RW'  
&>W (l.  
public void setNSplitter(int nCount) fKTDt%  
{ `*" H/Q
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nSplitter = nCount; (zs4#ja2,  
} p2Dh3)&  
} <g3du~  
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UR1JbyT  
/* B.22 DuE#  
**Utility.java 0i5y(m&7  
*/ bB:r]*_ s]  
package NetFox; 3`fJzS%O  
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public class Utility { p<=(GY-  
v@fe-T&0  
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public Utility() kqKj7L  
{ lh\ICN\O  
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} '?"t<$b
 
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//线程睡眠 (odR'#  
public static void sleep(int nSecond) r zMFof  
{ Ew %{ i(d  
try{ %XP_\lu]  
Thread.sleep(nSecond); D!bKm[T  
} k_D4'(V:b  
catch(Exception e) 4<G?  
{ 7Wwp )D  
e.printStackTrace (); }W:*aU  
} 9Fy\t{ks  
} ""1#bs{n  
bBUbw*DF)  
//日志 j+DE|Q&]I  
public static void log(String sMsg) 3h9Sz8  
{ ORGv)>C|  
System.err.println(sMsg); bQ-Gp;]  
} E`Jp(gK9F  
`fBG~NDw  
-}{%Q?rYj  
public static void log(int sMsg) qQfqlD<  
{ #XTY7,@P  
System.err.println(sMsg); Gb(C#,xbK  
} nG"tO'J6  
} 
@+'c+
  
k}-yOP{  
:/C ?
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/* ;^R A!Nj  
**TestMethod.java .:}.b"%m  
*/ #ZG3|#Q=L  
package NetFox; <y@,3DD3A9  
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public class TestMethod { T-4/d5D[  
xGYSi5}z  
EY+/.=$x  
public TestMethod() &/Eg2  
{ ///xx/weblogic60b2_win.exe Lw*;tL<,  
try{ 9[cp7
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }J
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//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A<4_DVd@@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); p"Ot5!F>  
fileFetch.start(); Jy \2I{I'  
} PX;Vo~6  
catch(Exception e){e.printStackTrace ();} 3/X-Cr+d  
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0B=[80K;8  
} aSc{Ft/O  
6!P`XTTE  
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public static void main(String[] args) Ne3R.g9;Z  
{ exfmq  
new TestMethod(); uxWFM $  
} V,V*30K5  
} QL2Nz@|k  
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