http断点续传简单实现（java)

/* iz"3\{aN  
**SiteFileFetch.java 1MA@JA:T  
*/ G.U5)4_^  
package NetFox; AN9[G  
import java.io.*; 5c-N0@\  
import java.net.*; (S^ck%]]a!  
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public class SiteFileFetch extends Thread { 2)/NFZ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean XT@Mzo49z\  
long[] nStartPos; //开始位置 '7Ig.K&  
long[] nEndPos; //结束位置 DHfB@/q#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 v+1i=s2$  
long nFileLength; //文件长度 PQj<[rY
 
boolean bFirst = true; //是否第一次取文件 %kU'hzLg  
boolean bStop = false; //停止标志 J^3H7 ]  
File tmpFile; //文件下载的临时信息 vH?9\3  
DataOutputStream output; //输出到文件的输出流 CP` XUpX`&  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 8TZENRzx-|  
public SiteFileFetch(SiteInfoBean bean) throws IOException =7ydk"xM*  
{ 0-2"FdeQU  
siteInfoBean = bean; h
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); yFpySvj}  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q^bO*bv  
if(tmpFile.exists ()) );}t&}  
{ SQ#7PKH  
bFirst = false; +2T!
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read_nPos(); WtX>Qu|  
} oO=o|w|T  
else 7!2 HNg  
{ BgRZ<B`  
nStartPos = new long[bean.getNSplitter()]; 3x5!a5$Y  
nEndPos = new long[bean.getNSplitter()]; %AR^+*Nu  
} %%g-GyP 1  
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_ 6:ww/  
} %cW;}Y[?P  
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public void run() %<}=xJf>1  
{ ; Zq/eiB  
//获得文件长度 }e=e",
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//分割文件 5()Fvae{k  
//实例FileSplitterFetch yr4ou  
//启动FileSplitterFetch线程
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//等待子线程返回 J_
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try{ zLek&s&-  
if(bFirst) FDLd&4Ex  
{ V-vlTgemwc  
nFileLength = getFileSize(); <TjBd1  
if(nFileLength == -1) zk>h u<_  
{ |< N frz  
System.err.println("File Length is not known!"); NfF~dK|  
} koH4~m{  
else if(nFileLength == -2) %D^bahf  
{ &`@M8-m#F  
System.err.println("File is not access!"); /4C`k=>  
} eF1.VLI  
else yDtOpM8<{  
{ $pFk"]=  
for(int i=0;i<nStartPos.length;i++) f9'] jJ+  
{ 6q%ed UED  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); oBw}hH,hp  
} n>llSK  
for(int i=0;i<nEndPos.length-1;i++) +"L$ed(=nJ  
{ "=A|K~b  
nEndPos = nStartPos[i+1]; B| Q6!  
} rl|Q)A{  
nEndPos[nEndPos.length-1] = nFileLength; ~t9Mh^gij  
}  ? ICDIn  
} /J;]u3e|  
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fq Y1ggL  
//启动子线程 3'@&c?Fye  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $Q4=37H+  
for(int i=0;i<nStartPos.length;i++) nW&$
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{ #`j][F@N  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]<X2AO1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), vPsq<l}  
nStartPos,nEndPos,i); X,Zd=
 
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #{w5)|S#JD  
fileSplitterFetch.start(); g8Aj `O  
} D-iUN  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), lJj&kVHb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); MOLO3?H(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ji##$xC  
nEndPos = " + nFileLength); A`C-sD>  
// fileSplitterFetch[nPos.length-1].start(); r|bPR!0  
)KE_t^$  
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//等待子线程结束 )l{A{f6O  
//int count = 0; YOKR//|3  
//是否结束while循环 N ^f}ui i  
boolean breakWhile = false; > Z++^YVE  
.Qk{5=l6P  
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while(!bStop) ZvyjM
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{ ;o%:7&  
write_nPos(); IQoH@l&Xk  
Utility.sleep(500); sU*3\  
breakWhile = true; UKYupLu5  
Zsk?QS FE  
s*+ZYPk  
for(int i=0;i<nStartPos.length;i++) Z~R
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{ Mz}i[|U\  
if(!fileSplitterFetch.bDownOver) +_-Y`O!Q  
{ b_mWu@$  
breakWhile = false; 2*YP"R
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break; zP|*(*  
} y&3TQ]f\  
} %/md"
S  
if(breakWhile) kdd7Xbw-  
break; kDg{>mf  
wXcMt>3  
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//count++; H8<m9zDvl  
//if(count>4) !?n50  
// siteStop(); 7BK46x  
} 776 nWw)  
!*8#jy  
J5-rp|  
System.err.println("文件下载结束！"); 3z$HKG  
} /evaTQPz  
catch(Exception e){e.printStackTrace ();} FSVS4mtiX\  
} ^ `E@/<w8  
aulaX/'-_  
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//获得文件长度 _&K\D p&@  
public long getFileSize() Lv^a+'  
{ tNYJQ  
int nFileLength = -1; &R0OeRToUb  
try{ +&?'KZ+Z_v  
URL url = new URL(siteInfoBean.getSSiteURL()); 1=i
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tgK x4  
httpConnection.setRequestProperty("User-Agent","NetFox"); EuLXtq  
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int responseCode=httpConnection.getResponseCode(); &1oaZY w  
if(responseCode>=400) ujow?$&  
{ v<%]XHN  
processErrorCode(responseCode); z?I+u*rF6  
return -2; //-2 represent access is error Plb}dID"  
} TJE% U0Ln  
::0aY;D2  
5a8JVDLX^  
String sHeader; 'G52<sF  
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for(int i=1;;i++) B,w:
DX  
{ }FHw" {my  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); uSH>$;a  
//Utility.log(in.readLine()); CGCQa0  
sHeader=httpConnection.getHeaderFieldKey(i); i1tVdbC]  
if(sHeader!=null) S!u6dz^[$X  
{ `:V}1ioX5  
if(sHeader.equals("Content-Length")) Ri9Kr  
{ 7&=-a|k~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); p| Vmdnb  
break; Lf[G>0t&n  
} !-F^VGD(8  
} 7 kEx48  
else Oi6f8*,  
break; P=&'wblm?  
} 2%`^(\y  
} D!c1;IHZ  
catch(IOException e){e.printStackTrace ();} wwo(n$!\  
catch(Exception e){e.printStackTrace ();} j!6elzg
 
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Utility.log(nFileLength); 'y'T'2N3  
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return nFileLength; xi;/^)r  
} U? {'n#n 5  
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'.=Wk^,Ua  
//保存下载信息（文件指针位置） I93 ~8wQ  
private void write_nPos() q-A`/9  
{ @47[vhE  
try{ )>-77\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); J'I1,5(  
output.writeInt(nStartPos.length); }Q47_]5  
for(int i=0;i<nStartPos.length;i++) e$ThSh\+(  
{ av'd%LZP  
// output.writeLong(nPos); [`y:M&@  
output.writeLong(fileSplitterFetch.nStartPos); C}n[?R  
output.writeLong(fileSplitterFetch.nEndPos); MMd0O X)P  
} TS\9<L9S  
output.close(); Uc_'3|
e  
} LDT'FwMjy  
catch(IOException e){e.printStackTrace ();} $
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catch(Exception e){e.printStackTrace ();} GS$ZvO  
} c1pq]mz|z  
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//读取保存的下载信息（文件指针位置） ,Wz[tYL*  
private void read_nPos() 6U;Jg
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{ 9@$tiDV  
try{ #H'sZv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "Cz
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int nCount = input.readInt(); fR+Ov8PCq  
nStartPos = new long[nCount]; X_vI0YX9  
nEndPos = new long[nCount]; 3*CzXK>`M&  
for(int i=0;i<nStartPos.length;i++) +A]&AkTw  
{ Z
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nStartPos = input.readLong(); d9`3EP)n  
nEndPos = input.readLong(); 1mT|o_K{ T  
} ~C}
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input.close(); ?2JS&i  
} 3g?MEM~  
catch(IOException e){e.printStackTrace ();} 9\AEyaJFZ  
catch(Exception e){e.printStackTrace ();}  1m&!l6Jk  
} fo/ D3  
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private void processErrorCode(int nErrorCode) zF[3%qZE:T  
{ 4]Un=?)I  
System.err.println("Error Code : " + nErrorCode); Paae-EmC  
} U@o2gjGN  
OVDMC4K2z!  
_7-"VoX  
//停止文件下载 QVnO
  
public void siteStop() |#DC.Ga!  
{ 7bgnZ]r8t  
bStop = true; .Ws iOJU  
for(int i=0;i<nStartPos.length;i++) &Iv\jhq  
fileSplitterFetch.splitterStop(); n;-x!Gs  
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} x:f|3"\s  
} OvyB<r  
//负责部分文件的抓取 GCf._8;%  
**FileSplitterFetch.java 
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*/ t-v^-#  
package NetFox; 9s;!iDFn  
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|%M{kA-  
import java.io.*; sYAG,r>h  
import java.net.*; '0'"k2"vC  
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public class FileSplitterFetch extends Thread { adRNrt*!  
r6O7&Me<  
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String sURL; //File URL V\iIvBpWg  
long nStartPos; //File Snippet Start Position ,xAM[h&  
long nEndPos; //File Snippet End Position Y(#d8o}}#  
int nThreadID; //Thread's ID ]>VJ--fH  
boolean bDownOver = false; //Downing is over RT.wTJS;  
boolean bStop = false; //Stop identical |x _-I#H  
FileAccessI fileAccessI = null; //File Access interface _|^&eT-u  
d&[M8(  
*pcbwd!/  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ZaukMEq  
{ oW yN:Qh  
this.sURL = sURL; b6LC$"t0  
this.nStartPos = nStart; C:tSCNH[  
this.nEndPos = nEnd; [I+)Ak5  
nThreadID = id; +WV_`Rx#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 e5WdK  
} >6.[i@RmWU  
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)+jK0E1  
public void run() g9FVb7In_  
{ Ov~S2?E8  
while(nStartPos < nEndPos && !bStop) 5CH-:|(;=  
{
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try{ .J<qfQ  
URL url = new URL(sURL); w]o:c(x@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^|FVc48{  
httpConnection.setRequestProperty("User-Agent","NetFox"); s60:0>  
String sProperty = "bytes="+nStartPos+"-"; NE=#5?6%g7  
httpConnection.setRequestProperty("RANGE",sProperty); _Cv[`e.  
Utility.log(sProperty); *uI hxMX  
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InputStream input = httpConnection.getInputStream(); V<~_OF  
//logResponseHead(httpConnection); B>
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byte[] b = new byte[1024]; W[1f]w3  
int nRead; PtPGi^
 
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Dj,+t+|  
{ &G7)s%q  
nStartPos += fileAccessI.write(b,0,nRead); w{:Oa7_A  
//if(nThreadID == 1) XoH[MJC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *Lb(urf  
} 0?5%  
Fl#VKU3h  
ERX|cc  
Utility.log("Thread " + nThreadID + " is over!"); !5E%W[  
bDownOver = true; XW&8T"q
7  
//nPos = fileAccessI.write (b,0,nRead); Q[ 9rA  
} ,/w852|ub  
catch(Exception e){e.printStackTrace ();} [FAOp@7W  
} lE2wkY9^/  
} Oc"'ay(g  
:~0^ib<v;  
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//打印回应的头信息 |`94Wj<  
public void logResponseHead(HttpURLConnection con) .Kh(F6 s  
{ ok\/5oz  
for(int i=1;;i++) oQ-|\?{;A  
{ hD6ur=G8u  
String header=con.getHeaderFieldKey(i); Jc"$p\ $-  
if(header!=null) 11@2;vw  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); LjH&f 4mY  
Utility.log(header+" : "+con.getHeaderField(header)); q~g&hR}K  
else [!dnm1  
break; +SuUI-.  
} ku[=QsMv  
} X>@.-{6T  
\\R*V'e!  
0oi5]f6g?8  
public void splitterStop() }ygb
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{ zfr(dQ  
bStop = true; P^_d$  
} Ng_rb KXC#  
\}4#**]  
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} qK6 uU9z  
ev;5?9\E  
[Tb3z:UUvf  
/* u>Axq3F  
**FileAccess.java dl7p1Cr  
*//文件访问(定位，写) *F8uu.  
package NetFox; &h4Z|h[01  
import java.io.*; l=-dK_I?  
\")YKN=W  
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public class FileAccessI implements Serializable{ ZAo)_za&mH  
0JZq:hUd  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 W-]yKSob  
RandomAccessFile oSavedFile; ]N(zom_0d  
long nPos; Dpp52UnTE  
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public FileAccessI() throws IOException p3A-WK|NX  
{ [vjkU7;7A  
this("",0); >gi{x|/  
} _9O }d  
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public FileAccessI(String sName,long nPos) throws IOException 4Tzu"y  
{ 9 K /  
oSavedFile = new RandomAccessFile(sName,"rw"); %wjU^Urya  
this.nPos = nPos; TNPGw!  
oSavedFile.seek(nPos); FO'. a  
} #u=O 5%.  
]kplb0`  
ubCJZ"!  
public synchronized int write(byte[] b,int nStart,int nLen) aXK
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{ EPd.atA  
int n = -1; E?q'|f  
try{ 1'U%7#;E  
oSavedFile.write(b,nStart,nLen); -ZoOX"N}  
n = nLen; (B/F6 X;o.  
} IO&#)Ft  
catch(IOException e) k2tX$\E  
{ (zLIv9$  
e.printStackTrace (); q!oZ; $  
} z#E,96R
 
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return n; K{w=qJBM  
} k;:u| s8NS  
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} VQNH@g^gqr  
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/* .HyiPx3^  
**SiteInfoBean.java K~ /V  
*/ xo_k"'f+  
package NetFox; UCj#t!Mw  
Dp6"I!L<|  
5~R{,]52  
public class SiteInfoBean { S| -{wC%  
n_Hnk4  
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private String sSiteURL; //Site's URL +VW]
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private String sFilePath; //Saved File's Path 2Ku#j ('  
private String sFileName; //Saved File's Name y`@4n.Q  
private int nSplitter; //Count of Splited Downloading File vls> 6h  
[c!vsh]^  
 iIEIGQx  
public SiteInfoBean() ~V- o{IA  
{//nSplitter的缺省值为5 }]GK@nn7  
//default value of nSplitter is 5 5sCky)N  
this("","","",5); b!
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} ;WAu]C|  
_ktSTzH0  
?d#(ian  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?'#;Y"RT  
{ n|,Vm@zV  
sSiteURL= sURL; MGC0^voe  
sFilePath = sPath; -bu. *=  
sFileName = sName; [3NV #  
this.nSplitter = nSpiltter; ~t3?er& R  
,H(vD,54g  
0|Ft0y`+  
} !9cPNIi  
+
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public String getSSiteURL() )ZU#19vr7  
{ lz0]p  
return sSiteURL; KIY_EE$?  
} 8=Y|B5  
qq%_ksQ  
^[z\KmUqt  
public void setSSiteURL(String value) )3\rp$]1  
{ ZU@jtqq  
sSiteURL = value; ~9;mZi1-  
} *7V{yK$O|  
{Om3fSk:  
^g){)rz|  
public String getSFilePath() ghQsS|)p.  
{ M6Z`Pwv];  
return sFilePath; acZ|H  
} J;Xz'0
 
:*%\i' $!/  
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public void setSFilePath(String value) ,ZW.P`  
{ ][qA@3^Tw  
sFilePath = value; Ip\g^ia  
}
;ypO'  
54_m{&hb  
*YOnX7*Km  
public String getSFileName() 8-6{MJ?F  
{ vKLG9ovlY  
return sFileName; H$iMP.AK  
} \/%Q PE8  
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N5]68Fu'({  
public void setSFileName(String value) HY#("=9< h  
{ 8(K~QvE~  
sFileName = value; ]@]"bF!Dn  
} t$D[,$G9  
2YEn)A@8  
L| qY  
public int getNSplitter() [beuDZA  
{ ,\RCgc  
return nSplitter; mM~Q!`Nf.  
} n!orM5=:O  
Y(mwJud|  
UM^hF%  
public void setNSplitter(int nCount) 5S?Xl|8E  
{ Ek\Zi#f<  
nSplitter = nCount; ViONG]F  
} 
;yoq/  
} r2`?Ta  
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/* 5Z0x2jV  
**Utility.java w8zQDPVB%  
*/ JsdEA  
package NetFox; imuHSxcaV  
8[XNFFUZs  
"K]4j]yU
 
public class Utility { wOSNlbQ5jl  
bJvRQrj*3  
_J`M>W)8  
public Utility() t*$@QO  
{ &$ 9bC't6  
a#@opUn-  
N* QI>kzU  
} !b Km}1T  
yw^,@'  
//线程睡眠 iE{SqX  
public static void sleep(int nSecond) aUQq<H'R  
{ Oms`i&}"}  
try{ B!lw>rUMQ  
Thread.sleep(nSecond); fe,CY5B{  
} 7X"cu6%\  
catch(Exception e) !o7.L%S  
{ (yVI<Os{a  
e.printStackTrace (); VzNH%  
} dWEx55>,1  
} b ;b1V  
ZGBcy}U(k  
//日志 9)`wd&!  
public static void log(String sMsg) :I8t}Wg  
{ O\z%6:'M  
System.err.println(sMsg); fNumY|%3  
} -8:@xG2  
5VS<
I\o}  
xC]/i(+bA  
public static void log(int sMsg) g>{=R|uO5  
{ [o "@*kf  
System.err.println(sMsg); 6{ Eh={:b  
} mD:!"h/
 
} 4D5)<3N=d'  
scmbDaOn  
#';r 0?|  
/* /nNHI34  
**TestMethod.java 01b0;|  
*/ K} @q+  
package NetFox; 7Udr~0_)  
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lH8?IkK,g  
public class TestMethod { nN:i{t4f  
3zkq'lZ  
n/-I7Q!;u  
public TestMethod() @,hvXl-G*  
{ ///xx/weblogic60b2_win.exe BRT2=}A  
try{ u=5^xpI<D
 
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P]G2gDO  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -3C~}~$>`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }j QwP3eY  
fileFetch.start(); 3UEh%Ho  
}  zcc]5>  
catch(Exception e){e.printStackTrace ();} &F)lvtt|  
:v+39  
V*)gJg  
} #gP\q?5Ov  
i=+ "[h^  
#Uo 9BM  
public static void main(String[] args) vU_#(jZ  
{ }6\p7n  
new TestMethod(); :(Gg]Z9^8  
} SExd-=G  
} @d)6LA9Ec  
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