http断点续传简单实现（java)

/* )(h<vo)-zX  
**SiteFileFetch.java +a|u,'u  
*/ asL!@YE  
package NetFox; >a)6GZ@  
import java.io.*; F>U*
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import java.net.*; 0IxHB|^$  
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public class SiteFileFetch extends Thread { K_}81|=  
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SiteInfoBean siteInfoBean = null; //文件信息Bean /rnP/X)T  
long[] nStartPos; //开始位置 Q5c13g2
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long[] nEndPos; //结束位置 X=[`+=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 k8w:8*y'.  
long nFileLength; //文件长度 4`p[t;q  
boolean bFirst = true; //是否第一次取文件 {PkPKp  
boolean bStop = false; //停止标志 ]//Dd/L6  
File tmpFile; //文件下载的临时信息 oRHWb_$"  
DataOutputStream output; //输出到文件的输出流 [(iJj3s!  
U(\ ^!S1  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 7!q.MOYm  
public SiteFileFetch(SiteInfoBean bean) throws IOException ka<rlh<h  
{ }qN   
siteInfoBean = bean; vqRW^>~-B  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); e$4l[&kH_  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g.x]x#BC  
if(tmpFile.exists ()) eXCH*vZY  
{ bdyIt)tK+  
bFirst = false; K~14;  
read_nPos(); V3[>^ZCA  
} x<>In"QV
 
else q&@q/9kz  
{ e[%g'}D:-  
nStartPos = new long[bean.getNSplitter()]; Ew2ksZ>B]&  
nEndPos = new long[bean.getNSplitter()]; J72YZrc  
} _j?/O)M c  
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} p} i5z_tS  
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public void run() A{ Ejk|  
{ \"Aw ATQ  
//获得文件长度 jHpFl4VPz  
//分割文件 *h2)$^P%  
//实例FileSplitterFetch #6za  
//启动FileSplitterFetch线程 (\ Gs7  
//等待子线程返回 ^vr`t9EE  
try{ -MItZ  
if(bFirst) N}7tjk  
{ 22"/|S  
nFileLength = getFileSize(); YojYb]y+j  
if(nFileLength == -1) S@vLh=65  
{ Ng1uJa[k!d  
System.err.println("File Length is not known!"); XkuZ2(  
} yWZ%|K~$  
else if(nFileLength == -2) >@StKj  
{ X]v.Yk=wu  
System.err.println("File is not access!"); k?ksv+e\
 
} MUqV$#4@I  
else @(s"5
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{ P[a\Q`}L  
for(int i=0;i<nStartPos.length;i++) {9YNv<3  
{ C]DvoJmBs  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @G0j/@v  
} uNG?`>4>  
for(int i=0;i<nEndPos.length-1;i++) \&5t@sC  
{ CD
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nEndPos = nStartPos[i+1]; %)G]rta#  
} MYF6tZ*  
nEndPos[nEndPos.length-1] = nFileLength; 9UeK}Rl^n  
} |\S p IFH1  
} b+ J)  
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kc-v(WIC  
//启动子线程 1U;p+k5c  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; pm}!?TL  
for(int i=0;i<nStartPos.length;i++) ,MdK "Qa>  
{ ET}Dh3A  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Irnfr\l.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), i-_ * 5%A  
nStartPos,nEndPos,i); ,1&</R_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d}RR!i`<N  
fileSplitterFetch.start(); 4]3(Vyh`  
} 0s8w)%4$  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), J,j!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); l-RwCw4f  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "1Oe bo2  
nEndPos = " + nFileLength); #jNN?,ZK  
// fileSplitterFetch[nPos.length-1].start(); 3erGTa[|q  
&ZUV=q%g9n  
&
 !I$  
//等待子线程结束 o$-!E(p  
//int count = 0; ds"q1  
//是否结束while循环 sZ9VXnz24  
boolean breakWhile = false; V_Oj?MMpn  
>gFEA0-  
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while(!bStop) "iY=1F"\R  
{ .#ASo!O5q  
write_nPos(); hIv8A_>@`  
Utility.sleep(500); 1O,<JrE+-  
breakWhile = true; V,qc[*_3  
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for(int i=0;i<nStartPos.length;i++) D!d1%hac  
{ 2[qlEtvQ  
if(!fileSplitterFetch.bDownOver) Xv'5%o^i*  
{ *eonXJYD  
breakWhile = false; -r!sY+Z>  
break; 8Cw+<A*  
} U
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} }{.0mu9  
if(breakWhile) oyeJ"E2  
break; 4]18=?r>  
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//count++; fNnemn@>  
//if(count>4) @XL5$k[Y  
// siteStop(); d`+@ _)ea  
} O^,%V{]6\  
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System.err.println("文件下载结束！"); %}=:gF  
} QFtf.")[.  
catch(Exception e){e.printStackTrace ();} <4|/AF*>  
} mWPA]g(  
l@OY8z-_  
- .EH?{i  
//获得文件长度 <yHa[c`L  
public long getFileSize() 3/i_?G  
{ )IH|S5mG?  
int nFileLength = -1; `oq][|  
try{ b,Vg3BS  
URL url = new URL(siteInfoBean.getSSiteURL()); }[gk9uM_7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H${5pY_M  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ghb Jty`  
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int responseCode=httpConnection.getResponseCode(); %2jRJ  
if(responseCode>=400) M)JKe!0ad1  
{ ,s9gGCA  
processErrorCode(responseCode); :|tWKA  
return -2; //-2 represent access is error yHk}'YP  
} @jxAU7!  
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String sHeader; muJR~
4  
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}pMd/|A,  
for(int i=1;;i++) [,)G\  
{ V|n}v?f_q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |r%NMw #y  
//Utility.log(in.readLine()); t0*,%ge:<  
sHeader=httpConnection.getHeaderFieldKey(i); Oe["4C  
if(sHeader!=null) +-*Ww5Zti  
{ Jb (CH4|7  
if(sHeader.equals("Content-Length")) >{HQ"{Q  
{ PV\aQO.mo  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); UTL
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break; 5u89?-UD  
} #NZ#G~oeO  
} ^.|P&f~  
else p?v.42R:z  
break; _P{f+HxU  
} 'fIoN%  
} f~0CpB*X  
catch(IOException e){e.printStackTrace ();} s9)U",  
catch(Exception e){e.printStackTrace ();} ODO'!T-  
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Utility.log(nFileLength); lIUaGz|  
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return nFileLength; T{:~v+I=  
} S[ln||{  
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//保存下载信息（文件指针位置） * ",/7(  
private void write_nPos() HPz3"3n!  
{ :yi?<  
try{ Id}/(Pkq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {gkzo3  
output.writeInt(nStartPos.length); bQlvb  
for(int i=0;i<nStartPos.length;i++) g]Jt (aYK  
{ /L yoTBG  
// output.writeLong(nPos); BtA_1RO  
output.writeLong(fileSplitterFetch.nStartPos); 
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output.writeLong(fileSplitterFetch.nEndPos); )p^" J|  
} h%%ryQQ&<  
output.close(); J6[V7R[\  
} pv[Gg^  
catch(IOException e){e.printStackTrace ();} !Soz??~o/  
catch(Exception e){e.printStackTrace ();} Q_r}cL
/A  
} JJZu%9~[  
>2t.7UhDI  
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//读取保存的下载信息（文件指针位置） j"F?^0aR,Q  
private void read_nPos() _@5|r|P>  
{ vk0b b3){D  
try{ 'w z6Zt  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1]A$  
int nCount = input.readInt(); !*1$j7`tP  
nStartPos = new long[nCount]; .C*mDi)wZ  
nEndPos = new long[nCount]; %;eD.If}  
for(int i=0;i<nStartPos.length;i++) -^aJ}[uaI  
{ [o"<DP6w  
nStartPos = input.readLong(); ?:$\ t?e^  
nEndPos = input.readLong(); D 0 O^=v|  
} Fd86P.Df  
input.close(); ]?6Pt:N2  
} cE;n>ta"F  
catch(IOException e){e.printStackTrace ();} bQ3txuha  
catch(Exception e){e.printStackTrace ();} (yb$h0HN  
} kz\Ss|jl  
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private void processErrorCode(int nErrorCode) Gl"|t't(  
{ xwF mY'o  
System.err.println("Error Code : " + nErrorCode); 3Cw}y55_y  
} %vil~NU  
@9tzk [  
<I#nwoHN  
//停止文件下载 sg8[TFX@Z  
public void siteStop() hm*cGYV/  
{ b} 0G~oLP  
bStop = true; ZuFcJ?8i  
for(int i=0;i<nStartPos.length;i++) Vak\N)=u  
fileSplitterFetch.splitterStop(); ?KtF!:_C  
=(]Z%Q-V  
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} AP:Q]A6}  
} (^NYC$ZxM=  
//负责部分文件的抓取 SK*z4p  
**FileSplitterFetch.java Fq$r>tmV  
*/ GEK7q<  
package NetFox; rJ)j./c  
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import java.io.*; vSu dT  
import java.net.*; u4h0s1iI  
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public class FileSplitterFetch extends Thread { *4ido?  
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String sURL; //File URL e }Mf  
long nStartPos; //File Snippet Start Position g<N;31:c\  
long nEndPos; //File Snippet End Position ^)(-7H  
int nThreadID; //Thread's ID |h?2~D!+d  
boolean bDownOver = false; //Downing is over +CM>]Ze  
boolean bStop = false; //Stop identical Fw S>V2R  
FileAccessI fileAccessI = null; //File Access interface \xlG3nz  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException A;<w
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{ gYCr,-_i  
this.sURL = sURL; ?<`oKBn  
this.nStartPos = nStart; z2>LjM) #  
this.nEndPos = nEnd; [l3ys  
nThreadID = id; 57~y
7/0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ptc+ypTu  
} D4b-Y[/"  
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public void run() /5<=m:  
{ P6&%`$  
while(nStartPos < nEndPos && !bStop) egvb#:zW?  
{ ua)jGif  
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ftG3!}  
try{ o]Xt2E  
URL url = new URL(sURL); 41x"Q?.bY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a'-u(Bw  
httpConnection.setRequestProperty("User-Agent","NetFox"); d:kn%L6k_  
String sProperty = "bytes="+nStartPos+"-"; ae2Q^yLA  
httpConnection.setRequestProperty("RANGE",sProperty); lYTQg~aPm  
Utility.log(sProperty); X$;&Mdo.  
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*s,[Uy![  
InputStream input = httpConnection.getInputStream(); lLp,sNAj  
//logResponseHead(httpConnection); :r@
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byte[] b = new byte[1024]; _1NK9dp:  
int nRead; {l)$9!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) EJ>&\Iq  
{ fZezDm(Q  
nStartPos += fileAccessI.write(b,0,nRead); +J|H~`  
//if(nThreadID == 1) pB4Uc<e  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @)BO`;*$fF  
} r\d(*q3B  
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Utility.log("Thread " + nThreadID + " is over!"); lH;V9D^  
bDownOver = true; }DXG;L  
//nPos = fileAccessI.write (b,0,nRead); =gs-#\%  
} 'f!U[Qatg  
catch(Exception e){e.printStackTrace ();} NJ)Dw`|%|)  
} ~ney~Pz_  
} xZP*%yM  
+Q[uq!<VJk  
L;* s-j6y  
//打印回应的头信息 #R{>@]x`  
public void logResponseHead(HttpURLConnection con) 3*& Y'/!  
{ 0:`|T jf_  
for(int i=1;;i++) KW(a@X  
{ ~N/r;omVc  
String header=con.getHeaderFieldKey(i); mUbm3JIjJ  
if(header!=null) 4;I\%qes  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |DV?5>>  
Utility.log(header+" : "+con.getHeaderField(header)); 0_eqO'"  
else mwo:+^v(  
break; !(rAI  
} #n'.a1R  
}
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public void splitterStop() X+C*+k,z  
{ ~%8P0AP  
bStop = true; SfnQW}RGI  
} "~5cz0 H3v  
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} R7/S SuG6\  
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/* G;3%k.{  
**FileAccess.java ?id) 2V0s  
*//文件访问(定位，写) VD$5 Djq  
package NetFox; 1>OlBp  
import java.io.*; Ln4]uqMG.  
Z^:_,aJ?  
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public class FileAccessI implements Serializable{ PqV F}  
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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 BS*79heY  
RandomAccessFile oSavedFile; $ ]s^M=8  
long nPos; N<9 c/V  
y)fMVD"(  
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public FileAccessI() throws IOException lN#j%0MaUo  
{ 1EXT^2!D  
this("",0); F(yR\)!C  
} 68XJ`/d  
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8L  
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public FileAccessI(String sName,long nPos) throws IOException k1<^Ept  
{ `Pvi+:6\Y  
oSavedFile = new RandomAccessFile(sName,"rw"); 8f9wUPr  
this.nPos = nPos; Hw o _;fV  
oSavedFile.seek(nPos); LUbj^iQ9  
} DjM*U52Yfj  
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public synchronized int write(byte[] b,int nStart,int nLen) He(65ciT<O  
{ Jy)=TJ!y  
int n = -1; Nv
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try{ i%-yR DIX  
oSavedFile.write(b,nStart,nLen); Q>,&@  
n = nLen; z2i
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} (oGYnN,2  
catch(IOException e) xoKK{&J  
{ Byc;r-Q5V  
e.printStackTrace (); J'}+0mln  
} m$p}cok#+S  
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return n; A|\A|8=b  
} ,`}yJ*7  
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} ,VS\mG/}s  
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/* /oT~CB..  
**SiteInfoBean.java ZAr6RRv ^  
*/ \>6*U r  
package NetFox; ,)1C"'  
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public class SiteInfoBean { ',r` )9o  
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private String sSiteURL; //Site's URL <D.E.^Y  
private String sFilePath; //Saved File's Path !-lI<$S:  
private String sFileName; //Saved File's Name N;3!oo4  
private int nSplitter; //Count of Splited Downloading File sfX~X/  
juR>4SH  
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public SiteInfoBean() :qdyCsn2  
{//nSplitter的缺省值为5 V
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//default value of nSplitter is 5 CtCReH03  
this("","","",5); nnyT,e%  
} C~h#pAh  
Qn$'bK2V  
\6wltTW]#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @rYZ0`E9  
{ 1Vy8eI`4  
sSiteURL= sURL; LO_Xrj  
sFilePath = sPath; uVqc:Q"  
sFileName = sName; KNeVSZT  
this.nSplitter = nSpiltter; h>`[p
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-s0SQe{!_  
} zIF1A*UH  
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public String getSSiteURL() dHY@V>D'-  
{ PA^*|^;Xh  
return sSiteURL; > SZ95@Oh  
} ;5/Se"Nd  
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public void setSSiteURL(String value) 8'Q+%{?1t  
{ nOPB*{r|  
sSiteURL = value; =78y*`L  
} .4a|^ vT  
jA,y.(mR  
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public String getSFilePath() NOTG|\{  
{ -U2Su|:\N8  
return sFilePath; K}cZK  
} &>c=/]Lop  
7**zb"#y  
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public void setSFilePath(String value) (')t>B1Z  
{ ;j T{< Y  
sFilePath = value; 12 )  
} (Iv@SiZf(  
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public String getSFileName() RhJ3>D
L  
{ ,O:4[M!$w  
return sFileName; ()|e xWW  
} aUMiRm-  
cUug}/!I  
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public void setSFileName(String value) iYLg[J"  
{ c\.)vH  
sFileName = value; F7}yt  
} 7oE:]  
j/Kul}Ml\*  
#sU>L=  
public int getNSplitter()
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{ A@3'I ;  
return nSplitter; 'cCM[P+  
} ar@,SKU'K  
~[!Tpq5  
MTwzL<@$  
public void setNSplitter(int nCount) b|87=1^m[  
{ 9+(b7L   
nSplitter = nCount; %{ U (y#  
} @^0}wk  
} !v3d:n\W8  
|$tF{\  
\/dOv

[  
/* p_xJKQS  
**Utility.java %5L~&W}^"  
*/ l%V+]skS  
package NetFox; ."Pn[$'.  
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public class Utility { tG]W!\C'h  
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un\o&0}  
public Utility() ^d>m`*px  
{ [ !~8TF  
.&u @-Vm  
^Cp;#|g,  
} <DqFfrpc  
c@lF*"4  
//线程睡眠 &xr(Kb  
public static void sleep(int nSecond) &#C|  
{ cm!vuoB~~  
try{ h
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Thread.sleep(nSecond); *k\;G?  
} L]YJ#5  
catch(Exception e) E\2f"s  
{ e<DcuF<ZS  
e.printStackTrace (); ybf,pDY#f  
} pvWNiW:~k  
} PYCG#U  
 <}^p5
|
 
//日志 W^W.* ?e`  
public static void log(String sMsg) D!,'}G#  
{ P/S,dhs(  
System.err.println(sMsg);  de8xl  
} shLMj)7!  
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public static void log(int sMsg) :MYLap&L&  
{  zW?=^bE  
System.err.println(sMsg); ~- 
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} }w=|"a|,  
} a'q&[08  
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CT\rx>[J.6  
/* RSeav  
**TestMethod.java n1x3q/~  
*/ Vf(..
8  
package NetFox; AO-~dV  
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public class TestMethod { sCf)#6mI  
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public TestMethod() >y!R}`&0^t  
{ ///xx/weblogic60b2_win.exe 'K23oQwDB  
try{ k/Urz*O  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); FrRUAoFO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); A(XX2f!i  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }Oe4wEYN)  
fileFetch.start(); -g"Wi@Qr  
} >N0L
  
catch(Exception e){e.printStackTrace ();} cI6Td*vM  
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} )*}?EI4.  
@]]\r.DG  
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public static void main(String[] args) G[d]t$f=  
{ T7Y+ WfYh  
new TestMethod();
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} V\c`O  
} IUG}Q7w5  
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