http断点续传简单实现（java)

/* )y7SkH|  
**SiteFileFetch.java H>-?/H  
*/ {V!Jj6n  
package NetFox; =#i#IF42?  
import java.io.*; j${:Y$V
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import java.net.*; UC^Bn1  
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public class SiteFileFetch extends Thread { {Y9m;b,X  
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SiteInfoBean siteInfoBean = null; //文件信息Bean }0#cdw#gH  
long[] nStartPos; //开始位置 N b(f  
long[] nEndPos; //结束位置 &/J[PdSb$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 mmXLGLMd  
long nFileLength; //文件长度 =*q:R9V  
boolean bFirst = true; //是否第一次取文件 eB:obz  
boolean bStop = false; //停止标志 -K`0`n}  
File tmpFile; //文件下载的临时信息 .~a)  
DataOutputStream output; //输出到文件的输出流 |67j__XC  
U/M(4H3>H  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） x7J|  
public SiteFileFetch(SiteInfoBean bean) throws IOException q4$R?q:^  
{ ^yKP 99(  
siteInfoBean = bean; /h0<0b?i  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %HuQc^  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _[V.%k  
if(tmpFile.exists ()) #](k,% 2  
{ 4];Qpln  
bFirst = false; }[PbA4l.g  
read_nPos(); Y9m'RFZr  
} {=7W;uL  
else V|{ )P@Q  
{ #kX=$Bzk  
nStartPos = new long[bean.getNSplitter()]; I0O)MR<  
nEndPos = new long[bean.getNSplitter()]; Zg7~&vs$  
} x
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} bK%go  
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public void run() +*g[hRw[  
{ :*1Gs,  
//获得文件长度 `4Z#/g  
//分割文件 8&VwAo  
//实例FileSplitterFetch muo7KUT  
//启动FileSplitterFetch线程 1uv"5`%s  
//等待子线程返回 5JI+42S \  
try{ BoP%f'0N  
if(bFirst) `NV =2T  
{ <P( K,L?r  
nFileLength = getFileSize(); LaJc;Jt$  
if(nFileLength == -1) 6(oGU4  
{ h GS";
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System.err.println("File Length is not known!"); y]?%2ud/=  
} 9L?EhDcDV  
else if(nFileLength == -2) <l5{!g  
{ Yh:*.@  
System.err.println("File is not access!"); p&_a kQj  
} quf,ZK5  
else 2Z,;#t  
{ ekP=/;T#S  
for(int i=0;i<nStartPos.length;i++) ~MO'%
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{ 9XS+W w7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); '[5tc fG#z  
} F& H~JJ  
for(int i=0;i<nEndPos.length-1;i++) h|%d=`P,  
{ %M9^QHyo@  
nEndPos = nStartPos[i+1]; 2=!/)hw}  
} n=t%,[Op  
nEndPos[nEndPos.length-1] = nFileLength; *NDLGdQqz  
} *ARro Ndr  
} U*k$pp6\b~  
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//启动子线程 UNYU2ze'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; RGLwtN  
for(int i=0;i<nStartPos.length;i++) KEYM@,'  
{ pWps-e  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), e7/J:n$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), GG;M/}E9  
nStartPos,nEndPos,i); b]RnCu"  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9A3Q&@,  
fileSplitterFetch.start(); &)fPz-s  
} X~G"TT$)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?Dm!;Z+7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m^T$H_*;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", FL/y{;  
nEndPos = " + nFileLength); % C6 H(  
// fileSplitterFetch[nPos.length-1].start(); #)>>f  
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RLulz|jC  
//等待子线程结束 A1%V<im@Z  
//int count = 0; kf-ZE$S4  
//是否结束while循环 N4fuV?E`  
boolean breakWhile = false; ENJ]  
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while(!bStop) )CdglPK  
{ O:lD>A4{  
write_nPos(); f 21w`Uk48  
Utility.sleep(500); 1 ,D2][  
breakWhile = true; "!Mu5Ga  
uaJ5'*  
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for(int i=0;i<nStartPos.length;i++) #wM0p:<  
{ s o~p+]  
if(!fileSplitterFetch.bDownOver) ^5,ASU  
{ 'Q(A5zfN]Y  
breakWhile = false; fhfdNmtR)I  
break; fU)hn  
} Cn28&$:J  
} L<8y5B~W  
if(breakWhile) [.<vISRir  
break; zy$hDy0  
Z/beROW)  
wM!QU{Lz  
//count++; sSD(mO<(  
//if(count>4) IUc!nxF#  
// siteStop(); 3\mFK$#sr  
} gs'bv#4yd  
@4$F%[g h  
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System.err.println("文件下载结束！"); z+-k4  
} Z[({; WtF  
catch(Exception e){e.printStackTrace ();} Uut,cQ". d  
} v S%+  
2N)Ywqvj  
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//获得文件长度 sL&u%7>Re  
public long getFileSize() 8<.KWr  
{ #v(+3Hp  
int nFileLength = -1; iNQk{n  
try{ $(zJ  
URL url = new URL(siteInfoBean.getSSiteURL()); ZibHT:n  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qM1$?U  
httpConnection.setRequestProperty("User-Agent","NetFox"); zo\XuoZ  
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int responseCode=httpConnection.getResponseCode(); 4F:RLj9P!  
if(responseCode>=400) L</"m[  
{ gXw\_ue<  
processErrorCode(responseCode); AQ0L9

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return -2; //-2 represent access is error &S|laqH  
} JHO9d:{-  
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" *Ni/p$I  
String sHeader; 9m6w.:S  
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for(int i=1;;i++) "lmiGR*u  
{ 6#{= E@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); gWWy!H  
//Utility.log(in.readLine()); z6{0\#'K  
sHeader=httpConnection.getHeaderFieldKey(i); &F.lo9JJ  
if(sHeader!=null) >eUAHmXQ|  
{ xc*ys-Nv  
if(sHeader.equals("Content-Length")) i:[B#|%  
{ d1E~H]X4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9d2$F9]:o  
break; ORHC bw9  
} d!wd,Xj}  
} m]DjIs*@%h  
else Rwy:.)7B$q  
break; HE(U0<9c  
} CWDo_g$  
} %5z88-\  
catch(IOException e){e.printStackTrace ();} {'r*Jb0  
catch(Exception e){e.printStackTrace ();} ?2=c'%w7  
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Utility.log(nFileLength); ;w6\r!O,  
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return nFileLength;
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} b?y1cxTT  
{'}Ofj  
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//保存下载信息（文件指针位置） :YV!;dKJ  
private void write_nPos() xHL{3^  
{ < )?&Jf>_  
try{ J J3vC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i&bttSRNV  
output.writeInt(nStartPos.length); Nm^q.)dO  
for(int i=0;i<nStartPos.length;i++) {_ 1q`5o  
{ sY#K=5R  
// output.writeLong(nPos); hnY^Z_v!  
output.writeLong(fileSplitterFetch.nStartPos); (8
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output.writeLong(fileSplitterFetch.nEndPos); E=
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} H+: $ 7;  
output.close(); T[;{AXLeI  
} $==hr^H  
catch(IOException e){e.printStackTrace ();} hi ]+D= S  
catch(Exception e){e.printStackTrace ();} =oHJ_  
} $u"K1Q3  
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6>vj({,1Y*  
//读取保存的下载信息（文件指针位置） 0<Pe~i_=  
private void read_nPos() @?%"nK  
{ i
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try{ :8)4:4$^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); K8RloDjk_A  
int nCount = input.readInt(); uV\=EDno  
nStartPos = new long[nCount]; 43VuH  
nEndPos = new long[nCount]; +V7p?iEY  
for(int i=0;i<nStartPos.length;i++) BF@VgozW  
{ Cy2X>Tl"<E  
nStartPos = input.readLong(); \o3i9Q9C  
nEndPos = input.readLong(); Mz{
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} My1E@<  
input.close(); ah
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} woR)E0'qx  
catch(IOException e){e.printStackTrace ();} 4%]{46YnK  
catch(Exception e){e.printStackTrace ();} J$P]>By5:  
} -0Q!:5EC  
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;x7SY;0*  
private void processErrorCode(int nErrorCode) >AfJxdd1  
{ +0a',`yc  
System.err.println("Error Code : " + nErrorCode); p1D-Q7F  
} Ri3m438  
Z?@07Y[|K  
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//停止文件下载 UU !I@  
public void siteStop() !#?tA/t@  
{ +tA rH C]  
bStop = true; 9wwvh'T&NK  
for(int i=0;i<nStartPos.length;i++) 0FW=8hFp,  
fileSplitterFetch.splitterStop(); JBg>E3*N  
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} [n^___7  
} (;M"'.C  
//负责部分文件的抓取 cCeD3CuRA%  
**FileSplitterFetch.java WFdS#XfV  
*/ F 4hEfO3  
package NetFox; IaJ(T>"+  
un/R7"  
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import java.io.*; z/TZOFaM  
import java.net.*; M6I1`Lpf  
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public class FileSplitterFetch extends Thread { _Yhpj}KZ  
un\^Wmbw  
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String sURL; //File URL ~Ch`A@=5  
long nStartPos; //File Snippet Start Position JxWHrsh[  
long nEndPos; //File Snippet End Position bH.">IV  
int nThreadID; //Thread's ID 4EELaP|%  
boolean bDownOver = false; //Downing is over HWd,1  
boolean bStop = false; //Stop identical  D"Xm9 (  
FileAccessI fileAccessI = null; //File Access interface #}gc6T~0  
ox*Ka]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 6`s[PKP.  
{ r*$"]{m}  
this.sURL = sURL; +`4|,K7'  
this.nStartPos = nStart; 1ERz:\  
this.nEndPos = nEnd; +g;G*EP
7*  
nThreadID = id; vB,N6~r>  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6SmSu\lgV  
} :[rx|9M6  
'X?`+2wK   
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public void run() YnMph0\Y^  
{ bw[!f4~  
while(nStartPos < nEndPos && !bStop) 3! +5MsR+  
{ (5I]umtge  
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);6zV_^!  
try{ 3646.i[D  
URL url = new URL(sURL); (>jME  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |#sP1w'l]  
httpConnection.setRequestProperty("User-Agent","NetFox"); Vr^wesT\Hx  
String sProperty = "bytes="+nStartPos+"-"; N8vWwN[3  
httpConnection.setRequestProperty("RANGE",sProperty); 9UwDa`^  
Utility.log(sProperty); V- vVb  
3Q#VD)  
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InputStream input = httpConnection.getInputStream(); JrQN-e!  
//logResponseHead(httpConnection); s)N1@RBR  
x;SrJVDN  
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byte[] b = new byte[1024]; 3)xV-Y9  
int nRead; dV5$L e#y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)
/yOd]N;$  
{ pUPb+:^R  
nStartPos += fileAccessI.write(b,0,nRead); J3zb_
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//if(nThreadID == 1) =y4g. J\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J+;.t&5R  
} F3qi$3HM  
+
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Utility.log("Thread " + nThreadID + " is over!"); JvUKfsnu{  
bDownOver = true; &x;nP6mV  
//nPos = fileAccessI.write (b,0,nRead); [W2p}4(  
} 1{~9:U Q  
catch(Exception e){e.printStackTrace ();} o+nU{  
} s9
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} &3JbAJ|;X  
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//打印回应的头信息 ?;*mSQA`J  
public void logResponseHead(HttpURLConnection con) z!1j8o2  
{ V`%m~#Me  
for(int i=1;;i++) 7e40
}n
 
{ `)%eU~  
String header=con.getHeaderFieldKey(i); )rXP2Z  
if(header!=null) kxdLJ_  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ve=0_GR0  
Utility.log(header+" : "+con.getHeaderField(header)); (zhmZm  
else 2"mO"2d%  
break; /0r2v/0  
}  RFZrcM  
} H"-p^liw  
9+/<[w7  
Hp,r @  
public void splitterStop() 2M;{|U  
{ x=H*"L=  
bStop = true; jeW0;Cz J~  
} Mpj3<vj   
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} L*5&hPU  
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u'N'<(\k  
/* 9 ROKueP  
**FileAccess.java ~MXPiZG?  
*//文件访问(定位，写) H7{ 6t(0j  
package NetFox; -aO3/Ik[q  
import java.io.*; O,bj_CWx  
jf})"fz-*  
@^P=jXi<  
public class FileAccessI implements Serializable{ Z^h4%o-l{  

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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 J>+Dv?Ni$  
RandomAccessFile oSavedFile; gy>2=d  
long nPos; fkx 9I m4  
2L,e\]2Z  

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public FileAccessI() throws IOException "+rX*~  
{ H,uOshR  
this("",0); O@ "6)/  
} jeJGxfii  
O<+C$J|  
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public FileAccessI(String sName,long nPos) throws IOException B4{A(-Tc  
{ O|OPdD  
oSavedFile = new RandomAccessFile(sName,"rw"); & XrV[d[>  
this.nPos = nPos; KDY~9?}TM  
oSavedFile.seek(nPos); #<?j784  
} 7{b|+0W  
:Z/ig%  
pY:xxnE  
public synchronized int write(byte[] b,int nStart,int nLen) bG5c~  
{ .t["kaA  
int n = -1; Gd'^vqo<  
try{ T? =jKLPC  
oSavedFile.write(b,nStart,nLen); 6L*y$e"Qc  
n = nLen; xR%CS`0R  
} +\{!jB*g  
catch(IOException e) 1ltoLd\{  
{ =XYfzR  
e.printStackTrace (); eDy}_By^  
} v=/V<3  
4BCZ~_  
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return n; D}_\oE/n  
} bhg"<I  
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} +C+3DwN  
"#p)Z{v"!  
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/* jOe %_R  
**SiteInfoBean.java d$>1 2>>  
*/ "r|O /  
package NetFox; Et7AAV*8g  
r_o2d8  
5:AAqMa  
public class SiteInfoBean { aoC
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t=U[ ;?  
AU >d1S.  
private String sSiteURL; //Site's URL i1scoxX3\  
private String sFilePath; //Saved File's Path O,DA{> *m  
private String sFileName; //Saved File's Name 6bU/IVP  
private int nSplitter; //Count of Splited Downloading File )"q2DjfX*  
:1AOund  
v[~ U*#i  
public SiteInfoBean() wlkS+$<  
{//nSplitter的缺省值为5 ]P 2M  
//default value of nSplitter is 5 yhTe*I=Gk  
this("","","",5); $YW z~^f  
} &18} u~M  
PAqziq.  
Z&PwNr/  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 578Dl(I#)  
{ jIEK[vJ`  
sSiteURL= sURL; aeg5ij-]u@  
sFilePath = sPath; ;xs?^N|  
sFileName = sName; |_2O:
7qe  
this.nSplitter = nSpiltter; 1 iE  
lv{Qn~\y&  
n2TvPt\  
} 8rw;Yo<
k  
^D6JckW  
BV7GzJ2([{  
public String getSSiteURL() <Q%o}m4Kt  
{ y/Nvts2!C  
return sSiteURL; cU*7E39
 
} m-;u]X=a  
vL-%"*>v  
#opFUX-  
public void setSSiteURL(String value) BPC$ v\a  
{ & 8e~<  
sSiteURL = value; m,8A2;&,8  
} c?[A  
-B@jQg@ >  
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public String getSFilePath() B<_T"n'#b  
{ RJ@d_~%U  
return sFilePath; EV]exYWB  
} Kf(% aDYq  
3~M8.{ U#V  
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public void setSFilePath(String value) nfl6`)oW  
{ 3WaYeol`  
sFilePath = value; h/PWi<R i  
} 2,dGRf  
9;q@;)'5  
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public String getSFileName() 011 _(v  
{ 6nxf<1  
return sFileName; 5>/,25 99  
} Z\TH=UA  
#&&^5r-b-  
1jQz%^~  
public void setSFileName(String value) fz,8 <  
{ ]xV7)/b5G  
sFileName = value; bCc^)o/w  
} dZv-lMYBE  
q!}&<w~|  
v@< "b U  
public int getNSplitter() #2Mz.=#G  
{ >m%\SuXq  
return nSplitter; >|H=25N>;  
} 7nfQ=?XNK  
k1B7uA'h"G  
2I6c7H s  
public void setNSplitter(int nCount) BL,YJM(y  
{ Z#MPlw0B  
nSplitter = nCount; ~M,n
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} Jg|
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} 5ahAp];  
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.(nq"&u-*  
/* e)>Z&e,3  
**Utility.java LWf+H 4iZ}  
*/ aCy2.Qn  
package NetFox; rzY7f: '  
j{S\X'?   
p}O@%*p.  
public class Utility { <86upS6  
]-["sw  
q<.^DO~$L  
public Utility() d v"  
{ lOcvRF  
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e#SNN-hKsJ  
} V=\&eS4^"  
My Af~&Y+  
//线程睡眠 W!V06.  
public static void sleep(int nSecond) l'?/$?'e_Z  
{ p*n$iroy_{  
try{ .K;*uq:0  
Thread.sleep(nSecond); ]={:VsnL  
} Fl^.J<Dz  
catch(Exception e) 9akCvY#Q  
{ 5|wQeosXxI  
e.printStackTrace (); ,HYz-sK.  
} 5qR76iH)/  
} [t,grdw  
NM  
//日志 ^FF{71;
 
public static void log(String sMsg) Su6ZO'[)  
{ |4x&f!%m  
System.err.println(sMsg); xL=g(FN(6L  
} j?3J-}XC  
]oXd|[G  
ib*$3
Fn~  
public static void log(int sMsg) u,4,s[  
{ y/4 4((O  
System.err.println(sMsg); _Ev"/%  
} "?}QwtUW  
} -L</,>p  
3eFD[c%mN  
_OHz6ag  
/* 1h"0B  
**TestMethod.java _QkU,[E  
*/ x!]ZVl]  
package NetFox; wF$8#=  
,dK%[  
daY^{u3  
public class TestMethod { %ktU 51o  
^V_vpr]}P  
_av%`bb&z9  
public TestMethod() h&;\   
{ ///xx/weblogic60b2_win.exe FV!  
try{ ~$YFfv>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *.n9D  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); V?0|#=_mE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \Vr(P>  
fileFetch.start(); 1!0BE8s"@  
} eWW\m[k]}  
catch(Exception e){e.printStackTrace ();} W(a=ev2sa  
kc1 *@<L6  
X 4;+`  
} P=(\3ok  
6(<M.U_ft  
[ wr0TbtV  
public static void main(String[] args) &&Vz=6N  
{ cQS}pQyYN  
new TestMethod(); V~NS<!+q  
} +8mfq\Y1  
} .lOEQLt  
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