http断点续传简单实现（java)

/* X$_pDF&\z  
**SiteFileFetch.java 8+H 0  
*/ =]1
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package NetFox; =,8nfJ+x  
import java.io.*; ,P=.x%  
import java.net.*; k]~$AaNq  
Hz%<V*\{  
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public class SiteFileFetch extends Thread {
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SiteInfoBean siteInfoBean = null; //文件信息Bean @mb'!r  
long[] nStartPos; //开始位置 N?O^
"  
long[] nEndPos; //结束位置 stiYC#bI:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 AuZISb%6  
long nFileLength; //文件长度 \i\>$'f*z  
boolean bFirst = true; //是否第一次取文件 p3e=~{v*  
boolean bStop = false; //停止标志 8Wgzca Q*  
File tmpFile; //文件下载的临时信息 NMUF)ksjN  
DataOutputStream output; //输出到文件的输出流 [3x},KM  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） U2CC#,b!(  
public SiteFileFetch(SiteInfoBean bean) throws IOException {a15s6'd  
{ 204"\mv  
siteInfoBean = bean; U>@AE  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `ZT/lB`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +O^} t  
if(tmpFile.exists ()) m#4h5_N  
{ 2*a9mi  
bFirst = false; 3*\hGt,ZP  
read_nPos(); aU_l"+5>vq  
} CeM%?fr5  
else 2/\I/QkTs  
{ Mi\- 9-  
nStartPos = new long[bean.getNSplitter()]; YFW/ Fa\7  
nEndPos = new long[bean.getNSplitter()]; j8aH*K-l{  
} h6n!"z8H  
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} q_98=fyE6  
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public void run() Zr=B8wuT  
{ ?FwHqyFVlQ  
//获得文件长度 L >)|l  
//分割文件 W8r"dK  
//实例FileSplitterFetch bZ^'_OOn  
//启动FileSplitterFetch线程 Rt5pl,Nf  
//等待子线程返回 vU(fd!V ?  
try{ v*c"SI=@M=  
if(bFirst) lJ,\^\q  
{ 8kvA^r`  
nFileLength = getFileSize(); Spin]V  
if(nFileLength == -1) 3Tp8t6*nL  
{ B I=57  
System.err.println("File Length is not known!"); !;P[Y"h@r  
} 0d1!Q!PH3  
else if(nFileLength == -2) S!b?pl  
{ p.b#RY  
System.err.println("File is not access!"); 2 /*z5  
} H!Dj.]T  
else 'Gamb+[  
{ $s-B  
for(int i=0;i<nStartPos.length;i++) H328I}7  
{ ivB,s5<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ,~DKU*A_~  
} )u4=k
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for(int i=0;i<nEndPos.length-1;i++) 2%9L'-  
{ U"oHPK3"TA  
nEndPos = nStartPos[i+1]; )rlkQ'DN  
} QpRk5NeLe  
nEndPos[nEndPos.length-1] = nFileLength; #_UP}G$  
} *ae)<l3v  
} lY2~{Y|4s  
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GG-b)64h`  
//启动子线程 [:qJ1^UU  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; f6nuh&!-  
for(int i=0;i<nStartPos.length;i++) UZmo?&y  
{ f.bwA x  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }RKsS3}   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), n_k`L(8*  
nStartPos,nEndPos,i); A (p^Q  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BPm")DMo  
fileSplitterFetch.start(); ~wOMT  
} Zsmv{p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N9s.nu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); qk>SM|{  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", yeBfzKI{b  
nEndPos = " + nFileLength); XsDZ<j%x89  
// fileSplitterFetch[nPos.length-1].start(); Ts
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//等待子线程结束 Bjj=UtI  
//int count = 0; f8V )nM+v"  
//是否结束while循环 2J%L%6z8~  
boolean breakWhile = false; IXlk1tHN4I  
BE],PCpPr  
uI&0/  
while(!bStop) l!W!Gz0to  
{ (I(U23A~  
write_nPos(); /m,i,NX07  
Utility.sleep(500); ^)a:DKL  
breakWhile = true; -B! a O65^  
;' |CSjco  
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for(int i=0;i<nStartPos.length;i++) <|]i3_Z  
{ cIC/3g}]  
if(!fileSplitterFetch.bDownOver) Cbl
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{ Z;BEUtR c  
breakWhile = false; jTZi< Y:bB  
break; @<X[,Mj  
} a/H5Y,b>  
} qFLt/ >  
if(breakWhile) _qpIdQBo  
break; >{-rl@^H:  
fe"w--v  
>Z
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//count++; 7GG`9!l]D  
//if(count>4) UH;bg}=8  
// siteStop(); a`]ZyG*P  
} -[pfLo  
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System.err.println("文件下载结束！"); o4@d,uIw^  
} iTs"RW  
catch(Exception e){e.printStackTrace ();} :#_k`{WG  
} #7]>ozKm  
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//获得文件长度 u$aN~6HG  
public long getFileSize() SG&H^V8  
{ f)gV2f0t  
int nFileLength = -1; Eza^Tbq%j?  
try{ AE`UnlUSF  
URL url = new URL(siteInfoBean.getSSiteURL()); n "^rS}Y]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1vCp<D9<  
httpConnection.setRequestProperty("User-Agent","NetFox"); HZS.%+2  
Xc^(e?L4  
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int responseCode=httpConnection.getResponseCode(); C8YStT  
if(responseCode>=400) t6kLZ  
{ TDy)A2Z  
processErrorCode(responseCode); )56L`5#tS  
return -2; //-2 represent access is error Zy{hYHQ  
} _ouZd.
 
| z_av  
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String sHeader; 9&<c)sS&B  
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for(int i=1;;i++) *UJB*r  
{ 45iO2W uur  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n<HF]  
//Utility.log(in.readLine()); yp@cn(:~  
sHeader=httpConnection.getHeaderFieldKey(i);
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if(sHeader!=null) QwF.c28[  
{ p]Qe5@NT  
if(sHeader.equals("Content-Length")) a9_2b}t  
{ e8egxm  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); p)"EenUK  
break; u:J4Az^!  
} 6W7,EIf  
} :0Y.${h  
else d(9SkXr  
break; 'd;aAG  
} ;A*sub  
} .>PwbZ  
catch(IOException e){e.printStackTrace ();} jv1p'qs4  
catch(Exception e){e.printStackTrace ();} K@!hrye  
)=aqj@v  
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Utility.log(nFileLength); C:bA:O  
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return nFileLength; m9jjKu]|  
} ;i+(Q%LO  
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//保存下载信息（文件指针位置） XuZgyt"=r  
private void write_nPos() >s,*=a  
{ Pl#u,Y  
try{ L=s8em]7l  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Bxj4rC[  
output.writeInt(nStartPos.length); ?V_v=X%w  
for(int i=0;i<nStartPos.length;i++) F^TOLwix  
{ S_VzmCi  
// output.writeLong(nPos); -~lrv#5Q  
output.writeLong(fileSplitterFetch.nStartPos); !VrBoU4<d  
output.writeLong(fileSplitterFetch.nEndPos); !}1l8Y  
} y] Cx[  
output.close(); ]#q$i[Y  
} ^BI&-bR@  
catch(IOException e){e.printStackTrace ();} SL^%Zh/~  
catch(Exception e){e.printStackTrace ();} kjQI=:i=  
} AP=SCq;  
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6G-XZko~a  
//读取保存的下载信息（文件指针位置） K+yi_n L  
private void read_nPos() p{SIGpbR&  
{ Esg:  
try{ T).}~i;!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); {c&9}u$e  
int nCount = input.readInt(); gK dNgU  
nStartPos = new long[nCount]; "[Tr"nI  
nEndPos = new long[nCount]; Kj6+$l  
for(int i=0;i<nStartPos.length;i++) 6e}T zc\@(  
{ A?)(^  
nStartPos = input.readLong(); nRX<$OzTV  
nEndPos = input.readLong(); 3z8zZ1uzU  
} +yHzp   
input.close(); +,D82V7S  
} WCp[6g&%O  
catch(IOException e){e.printStackTrace ();} >S?7-2X  
catch(Exception e){e.printStackTrace ();} kaDn= ={YM  
} : R8+jO  
y92<(ziaX)  
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private void processErrorCode(int nErrorCode) u9+)jN<Yh  
{ U?(,Z$:N  
System.err.println("Error Code : " + nErrorCode); $ WWi2cI;  
} n4ti{-^4|d  
3|Ar~_]  
=)]RD%Oq  
//停止文件下载 91#n Aj%  
public void siteStop() %]O#t<D  
{ [Kbna>`  
bStop = true; O9p^P%U"  
for(int i=0;i<nStartPos.length;i++) 0upZ4eN  
fileSplitterFetch.splitterStop(); \nQEvcH  
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} z_z'3d.r7  
} 0E&XD&D  
//负责部分文件的抓取 R
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**FileSplitterFetch.java <)
@^TRS  
*/ Pp|pH|(n ,  
package NetFox; |C t Q  
<R#:K7>O  
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import java.io.*; ayA_[{j%X  
import java.net.*; :!,.c$M  
bW'Y8ok[v  
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public class FileSplitterFetch extends Thread { 'FN3r  
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^}GR!990  
String sURL; //File URL H329P*P  
long nStartPos; //File Snippet Start Position q?&JS  
long nEndPos; //File Snippet End Position [3W+h1  
int nThreadID; //Thread's ID @jD19=  
boolean bDownOver = false; //Downing is over j7HOh
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boolean bStop = false; //Stop identical ]6HnK%  
FileAccessI fileAccessI = null; //File Access interface Q $>SYvW  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y[fbmn^  
{ Lismo#  
this.sURL = sURL; 0j{K
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this.nStartPos = nStart; a3(f\MMxE  
this.nEndPos = nEnd; j;*= ^s  
nThreadID = id; aK9zw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 MK4CggoC  
} ;WL0  
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P99s  
public void run() m3_)UIJZ  
{ ^EKf_w-v  
while(nStartPos < nEndPos && !bStop) 
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{ R~BW=Dz,e  
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try{ mHC36ba  
URL url = new URL(sURL); GJuU?h#:/{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gr$H?|n l  
httpConnection.setRequestProperty("User-Agent","NetFox"); )i>T\B  
String sProperty = "bytes="+nStartPos+"-"; H*>5ne=x  
httpConnection.setRequestProperty("RANGE",sProperty); . J*2J(T,  
Utility.log(sProperty); K+c>Cj}H  
ymyk.#Z<%  
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InputStream input = httpConnection.getInputStream(); knZ<V%/e  
//logResponseHead(httpConnection); 1uhSP!b  
:y[tZ&*<_?  
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byte[] b = new byte[1024]; Ad`jV_z  
int nRead; \R<OT%8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 8f|+045E@  
{ MT@Uu  
nStartPos += fileAccessI.write(b,0,nRead); SkA"MhX  
//if(nThreadID == 1) '~'3x4B
o  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &Lgi  
} %|3UWN  
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b~FmX  
Utility.log("Thread " + nThreadID + " is over!"); aD3Q-a[  
bDownOver = true; 5($ '@u  
//nPos = fileAccessI.write (b,0,nRead); N DV_/BI  
} u@zBE? g  
catch(Exception e){e.printStackTrace ();} -^7n+ QX  
} uc;QSVWGy8  
} 9Uh nr]J.  
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//打印回应的头信息 S b3@7^  
public void logResponseHead(HttpURLConnection con) uw@|Y{(K r  
{ jDc5p3D&[]  
for(int i=1;;i++) x;R9Gc[5  
{ <$ Ar*<,6  
String header=con.getHeaderFieldKey(i); Z?-l-sK  
if(header!=null) T/C1x9=?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); W1J7$  
Utility.log(header+" : "+con.getHeaderField(header)); (wIpq<%  
else ouUU(jj02  
break; \6${Na'\  
} c =i6  
} NASRr   
)Hy|K1  
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public void splitterStop() 1{V*(=Tp  
{ 5ERycC y  
bStop = true; C zvi'
:  
} WChJ <[]W  
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} r yO\$m  
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/* @YTZnGG*  
**FileAccess.java Io&F0~Z;;(  
*//文件访问(定位，写) j7 D\O  
package NetFox; zW^@\kB0D  
import java.io.*; NUH#  
,9p 4(jjX  
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public class FileAccessI implements Serializable{ jM90 gPX>,  
R{hKl#j;>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 f+huhJS5e  
RandomAccessFile oSavedFile; gI^*O@Q4{b  
long nPos; .gWYKZM  
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public FileAccessI() throws IOException 6l>$N?
a  
{ ?J~(qaa;  
this("",0); 7m=tu?@  
} puz~Rfn#*  
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public FileAccessI(String sName,long nPos) throws IOException d1#;>MiU  
{ ~8Z0{^  
oSavedFile = new RandomAccessFile(sName,"rw"); :_Y@,CpIEg  
this.nPos = nPos; GKwm %A  
oSavedFile.seek(nPos); PDo%ob\Ym  
} X&6p_Lo  
i1?H*:]  
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public synchronized int write(byte[] b,int nStart,int nLen) x,z+l-y  
{ ?8n`4yO0  
int n = -1; n
rMm](Y45  
try{ DEL#MD!  
oSavedFile.write(b,nStart,nLen); *#,wV  
n = nLen; Jx@3zl  
} Nq)=E[$  
catch(IOException e) n||/3-HDj  
{ _}7N,Cx   
e.printStackTrace (); =x~HcsJ8!R  
} +)FB[/pXk  
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nj~1y')  
return n; C_Y^
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} 8|w_PP1oE  
iP;X8'< BC  
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} /4]M*ls  
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l=ZhHON  
/* Dm[4`p@IY\  
**SiteInfoBean.java ]w(i,iJ  
*/ A -G?@U  
package NetFox; .Kr?vD^nG  
t+5JIQY>  
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public class SiteInfoBean { -1~bWRYq  
Mjrl KI}f/  
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private String sSiteURL; //Site's URL Cw`v\ 9  
private String sFilePath; //Saved File's Path E3y"  
private String sFileName; //Saved File's Name g&H6~ +\
 
private int nSplitter; //Count of Splited Downloading File `6b!W0$ -  
T"XP`gk  
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public SiteInfoBean() J A ]s  
{//nSplitter的缺省值为5 a
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//default value of nSplitter is 5 ao<@a{G  
this("","","",5); BM#cosV7%h  
} ";cWK29\f  
nW3`Z1kq})  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]n0kO&  
{ GmB7@-[QA%  
sSiteURL= sURL; b,8W |  
sFilePath = sPath; a1Qg&s<  
sFileName = sName; Tz
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this.nSplitter = nSpiltter; =u(. Y  
^S'}RZ*>  
;GO>#yg4Eh  
} $6T*\(;T@A  
,YJ\ $?  
Q_xE:#!;  
public String getSSiteURL() EUU9JnQhBJ  
{ C+$dm)M/q  
return sSiteURL; PBb@J'b  
} >n)N=Zyu  
J.mEOo!>  
&""~Pn
8  
public void setSSiteURL(String value) K.n #;|  
{ K>9]I97g'  
sSiteURL = value; 7M<Ae D%  
} xCD|UC46?X  
s"<k)Xi  
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public String getSFilePath() el39HB$  
{ dy;Ue5  
return sFilePath; C".&m  
} IM}T2\tZ}  
p mcy(<  
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public void setSFilePath(String value)
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{ iV[g.sP-  
sFilePath = value; s(J,TS#I]  
} !9DqW&8  
' D+h_*H  
d>eVR  
public String getSFileName() .HF+JHIUu  
{ f*7/O |Gp  
return sFileName; F_U3+J>  
} `UL#g![J  
gR"'|c   
bWo-( qxq  
public void setSFileName(String value) 2c@R!*  
{ ~sshhuF  
sFileName = value; /cUcfe#X  
} (X@JlAfB  
={-\)j  
0F6^[osqtl  
public int getNSplitter() h #Od tc1)  
{ 7-.YVM~R  
return nSplitter; ?N<* ATCL  
} 6]rIYc[,  
k!b\qS~Q  
e'mm42  
public void setNSplitter(int nCount) ! R?r)G5E  
{ (EGsw o  
nSplitter = nCount; mnu4XE#|  
} So\(]S  
} 9%j_"+<c  
N&U=5c`Q'  
i)g=Lew  
/* 2@@OjeANsX  
**Utility.java LX'.up11X5  
*/ pI|Lt  
package NetFox; uuHR!  
X90
VJb]  
)uiYu3 I  
public class Utility { j{SRE1tqh  
VG^*?62  
r5> FU>7'  
public Utility() ?Ko)AP  
{ FA<|V!a  
R<@s]xX_  
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} j|TcmZGO  
N}b/;Y  
//线程睡眠 kB{  
public static void sleep(int nSecond) \:-#,( .V  
{ P7O$*  
try{ xV[X#.3  
Thread.sleep(nSecond); OF&{mJH"g'  
} RiqYC3Ka  
catch(Exception e) 9&fS<Hk  
{ A(2_hl-  
e.printStackTrace (); '8K5=|!J  
} i,1=5@rw5  
} 2W:R{dHE  
3 HOJCgit  
//日志 Fxdu)F,~u  
public static void log(String sMsg) z %{Z  
{ e`zx#v  
System.err.println(sMsg); oa$-o/DhB  
} {m~.'DU  
|1wfLJ4--l  
(+q#kKR  
public static void log(int sMsg) >=BH$4Ce  
{ ggtGecKm  
System.err.println(sMsg); b<>GF-`w  
} :kz*.1  
} _^;+_6&[  
QPB@qx#@  
5[}3j1  
/* Osncl5PD)  
**TestMethod.java 9W88_rE'e}  
*/ ".A+'pJ
  
package NetFox; yoiKt; S  
0YK`wuZGS  
nXPl\|pXt  
public class TestMethod { IV*@}~BJ  
nf=*KS\v  
a3D''Ra  
public TestMethod() %Z9&zmO  
{ ///xx/weblogic60b2_win.exe .'N:]G@!  
try{ ([SrIG>X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \^a(B{   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); t&}Z~Zp  
SiteFileFetch fileFetch = new SiteFileFetch(bean); gsFyZ  
fileFetch.start(); Tlc3l}B*Z  
} CZ*#FY  
catch(Exception e){e.printStackTrace ();} ap;?[B~Ga  
n+1!/H=d  
HYm |  
} [mwJ*GJ-  
5p!X}u]  
^'>kZ^w0  
public static void main(String[] args) 4g<F."  
{ h!.#r*vV  
new TestMethod(); u"eO&Vc  
} :j_OO5b!  
} &N4Jpa}w/%  
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