http断点续传简单实现（java)

/* Jvysvi{8  
**SiteFileFetch.java pNY+E5  
*/ !{
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package NetFox; d|UK=B^x  
import java.io.*; Za+26#g  
import java.net.*; -"u9s[L{  
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public class SiteFileFetch extends Thread { .Rq|F  
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SiteInfoBean siteInfoBean = null; //文件信息Bean -]1
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long[] nStartPos; //开始位置 X{SD3j=G#  
long[] nEndPos; //结束位置 /b*VFA/75  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 6qsT/  
long nFileLength; //文件长度 JJL#Y  
boolean bFirst = true; //是否第一次取文件 h=uv4&  
boolean bStop = false; //停止标志 OidF{I*O  
File tmpFile; //文件下载的临时信息 wyqXD.of  
DataOutputStream output; //输出到文件的输出流 l1X&Nw1W  
<mE)&7C  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -V Rby  
public SiteFileFetch(SiteInfoBean bean) throws IOException t/?x#X  
{ %M+ID['K9/  
siteInfoBean = bean; YG<7Zv  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7r=BGoA2E  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); >_ji`/d{  
if(tmpFile.exists ()) Y{]RhRR  
{ GT|=Kx$;  
bFirst = false; f_}FYeg  
read_nPos(); 9p ;)s  
} S^}@X?v  
else $<jI<vD+:  
{ @+LZSd+I  
nStartPos = new long[bean.getNSplitter()]; k@qn'Zi  
nEndPos = new long[bean.getNSplitter()]; L&td4`2y  
} ]|cL+|':y  
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vas   
} Xj:?V;  
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public void run() PxENLQ3a=  
{ ^cO^3=  
//获得文件长度 Q`#Y_N-h+  
//分割文件 D]nVhOg|  
//实例FileSplitterFetch !|P>%bi
 
//启动FileSplitterFetch线程 \wY? 6#;  
//等待子线程返回 2+pLDIIT  
try{ Xz`?
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if(bFirst) =y" lX{}G  
{ g0-hN%=6  
nFileLength = getFileSize(); _1w?nN'  
if(nFileLength == -1) 2J;h}/!H  
{ Q>y2C8rnJ/  
System.err.println("File Length is not known!"); 9;3f`DK@2k  
} [([?+Ouy  
else if(nFileLength == -2) :(A5,$  
{ S?.2V@Ic  
System.err.println("File is not access!"); ZRYs7 4<  
} uVJ;1H!  
else $Bd{Y"P@6  
{ ]kC/b^~+m  
for(int i=0;i<nStartPos.length;i++) ^hOnLy2  
{ j'lfH6_')e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); PfTjC"`,  
} D0(QZrVa  
for(int i=0;i<nEndPos.length-1;i++) q|)
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{ &f1dCL%z7  
nEndPos = nStartPos[i+1]; E7E>w#T5  
} Jt6~L5[_s  
nEndPos[nEndPos.length-1] = nFileLength; $0rSb0[  
} /M>8
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} 7<&
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|n-NK&Y(o  
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//启动子线程 S[!-M\b  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; w]w>yD>$  
for(int i=0;i<nStartPos.length;i++) Lc;4 Hg  
{ mVGQyX  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =VkbymIZ4y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), OZdiM&Zss  
nStartPos,nEndPos,i); gf6<`+
/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); D6!`p6r+  
fileSplitterFetch.start(); HpI[Af}l  
} x6A*vP0nm)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7B GMG|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @$ E&H`da  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <F!On5=W*  
nEndPos = " + nFileLength); qG.HJD  
// fileSplitterFetch[nPos.length-1].start(); <TmMUA)`}  
WlnmW(uahW  
3P C'P2  
//等待子线程结束 {<7!=@j  
//int count = 0; r (Ab+1b  
//是否结束while循环 +o)o4l%3  
boolean breakWhile = false; j["b*X`8G  
d[ql7  
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while(!bStop) !K;\{/8  
{ +5(
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write_nPos(); QjMH1S  
Utility.sleep(500); !%n3_tZC  
breakWhile = true; xMI4*4y(  
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for(int i=0;i<nStartPos.length;i++) hR"j[  
{ CSx V^  
if(!fileSplitterFetch.bDownOver) F8S -H"  
{ Gz;.?=&iF  
breakWhile = false; d0YN:lJc  
break;  ~0 <?^  
} `(A>7;]:  
} bY:A7.p7#  
if(breakWhile) omQaN#!,  
break; r(./00a  
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ikf6Y$nWfF  
//count++; >h>X/a(=~  
//if(count>4) !kZ9Ox9^  
// siteStop(); 3# G;uWN-  
} a[iuE`
  
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System.err.println("文件下载结束！"); qh;ahX~  
} _y{z%-  
catch(Exception e){e.printStackTrace ();} w[@>k@=  
} hmJ{'D1"  
&U:bRzD  
0,*clvH\;  
//获得文件长度 p$dVGvM(  
public long getFileSize() Hm@+(j(N96  
{ k4iu`m@^H  
int nFileLength = -1; WT$m*I  
try{ i8A{DMc,U  
URL url = new URL(siteInfoBean.getSSiteURL()); MJS4^*B\1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p$^}g:  
httpConnection.setRequestProperty("User-Agent","NetFox"); `HXP*Bp#  
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int responseCode=httpConnection.getResponseCode(); =pQA!u]QE  
if(responseCode>=400) *x3";
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{ CYA#:  
processErrorCode(responseCode); 4G;FpWQm  
return -2; //-2 represent access is error kyl
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} 7:x%^J+  
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String sHeader; )2T1g~8  
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for(int i=1;;i++) c%-s_8zvi  
{ y\L$8BSL  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Srw ciF  
//Utility.log(in.readLine()); N=hr%{}c  
sHeader=httpConnection.getHeaderFieldKey(i); j&n][=PL  
if(sHeader!=null) ' O1X+  
{ <I .p{Z  
if(sHeader.equals("Content-Length")) rJi;"xF8  
{ 2*:lFvwP  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); WJvD,VMz  
break; jT/S
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} VXEA.Mko  
} iR j/Tm*T'  
else 3In` !@EJ  
break; O<nJbsl_w  
} EacqQFErl  
} i-oi?x<u&(  
catch(IOException e){e.printStackTrace ();} KfpDPwP@  
catch(Exception e){e.printStackTrace ();} OU+oS,  
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Utility.log(nFileLength); u=B_cA}:  
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return nFileLength; 5HP6o  
} ?d`?Ss;v  
@@$=MSN  
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//保存下载信息（文件指针位置） ]Cd1&  
private void write_nPos() /VB n  
{ yU"lW{H@  
try{ IxC/X5Mp^q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (,$ H!qKy  
output.writeInt(nStartPos.length); DueQ1+ P  
for(int i=0;i<nStartPos.length;i++) c`~aiC`l  
{ x]umh{H~  
// output.writeLong(nPos); O8+e: K[D  
output.writeLong(fileSplitterFetch.nStartPos); 3vTX2e.w  
output.writeLong(fileSplitterFetch.nEndPos); IE*GF27n  
} oL0Q%_9hW  
output.close(); \z!*)v/{-  
} is&A_C7yg  
catch(IOException e){e.printStackTrace ();} )yp+!\  
catch(Exception e){e.printStackTrace ();} ]|g{{PWH  
} Kl.xe&t@j  
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//读取保存的下载信息（文件指针位置） ]Cy1yAv={  
private void read_nPos() [AE-~+m)^  
{ ypEcjVPD  
try{ >Ya+#j~CZ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); hU=n>g>nx  
int nCount = input.readInt(); /C"dwh"``  
nStartPos = new long[nCount]; T)Z2=5V  
nEndPos = new long[nCount]; 9u<4Q_I`  
for(int i=0;i<nStartPos.length;i++) =)5eui>{  
{ rqk1 F~j|  
nStartPos = input.readLong(); ^yDCX  
nEndPos = input.readLong(); >QRpRHtb  
} H?tonG.^(  
input.close(); Kd}cf0  
} J
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catch(IOException e){e.printStackTrace ();} S N_!o2F2  
catch(Exception e){e.printStackTrace ();} ^S!^$d*  
} 3XY;g{`=q  
n,sl|hv2U  
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private void processErrorCode(int nErrorCode) @2Xw17[f35  
{ tj 6 #lM9  
System.err.println("Error Code : " + nErrorCode); ^G'8!!ys  
} (!kOM% 3{  
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[B3qZ"  
//停止文件下载 $7~k#_#PC  
public void siteStop() D*3\4=6x  
{ *44^M{ti<  
bStop = true; l]RO'  
for(int i=0;i<nStartPos.length;i++) 3Gi#WV4$  
fileSplitterFetch.splitterStop(); q:N"mp<%  
vtw{ A}  
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} [.;$6C/?  
} FEgM4m.(G<  
//负责部分文件的抓取 IT& U%hw  
**FileSplitterFetch.java n1K"VjZk  
*/ g(xuA^~J  
package NetFox; cl4`FU  
5]cmDk  
n[4F\I>  
import java.io.*; }R5>ja0  
import java.net.*; g2L^cP>2  
bnBnE[y<'  
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public class FileSplitterFetch extends Thread { +r[u4?  
bTB/M=M  
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String sURL; //File URL @? 4-  
long nStartPos; //File Snippet Start Position K~"uZa^s  
long nEndPos; //File Snippet End Position O~yPe.  
int nThreadID; //Thread's ID +=#sam*i  
boolean bDownOver = false; //Downing is over W6f?/{Oo8  
boolean bStop = false; //Stop identical [*zB vj}G
 
FileAccessI fileAccessI = null; //File Access interface HFYN(nz}[  
:3WrRT,'L  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException KK"uSC  
{ nxH=Ut7{  
this.sURL = sURL; TJ9JIxnS  
this.nStartPos = nStart; I3uS?c  
this.nEndPos = nEnd; dr3
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nThreadID = id; :-HVK^$%  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 i-Ck:-J  
} 4Z>KrFO  
nQ>?{"  
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public void run() T7vilfO5G  
{ u50 o1^<X  
while(nStartPos < nEndPos && !bStop) yVd}1bX  
{ 27q9zi!Q  
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try{ Dd8*1,  
URL url = new URL(sURL); (xw)pR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6|gC##T  
httpConnection.setRequestProperty("User-Agent","NetFox"); @,0W(  
String sProperty = "bytes="+nStartPos+"-"; Pe[~kog,TP  
httpConnection.setRequestProperty("RANGE",sProperty); LwIl2u*  
Utility.log(sProperty); ?)<DEu:Y  
^(7<L<H  
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InputStream input = httpConnection.getInputStream(); 5X>b(`  
//logResponseHead(httpConnection); Gs]m; "o|  
t.|b285e  
M.|O+K z  
byte[] b = new byte[1024]; K?0f)@\nx  
int nRead; "<6X=|C  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {xb8H  
{ p^PAbCP'|3  
nStartPos += fileAccessI.write(b,0,nRead); lA}(63j+b  
//if(nThreadID == 1) e]-bB#-A  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LAqmM3{fA  
} @Bs7kjuX  
A?[06R5E#  
x*GGO)r  
Utility.log("Thread " + nThreadID + " is over!"); nxH+XHv  
bDownOver = true; TZ8:3ti  
//nPos = fileAccessI.write (b,0,nRead); Y?G9d6]Lk6  
} "&(
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catch(Exception e){e.printStackTrace ();} S*,DX~vig  
} ST'M<G%4E  
} `j+aAxJ=\  
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WK;X6`  
//打印回应的头信息 ?v8.3EE1\o  
public void logResponseHead(HttpURLConnection con) $g? ]9}p  
{
:D(4HXHK%  
for(int i=1;;i++) le1  
{ e<wA["^  
String header=con.getHeaderFieldKey(i); C-Y~T;53  
if(header!=null) @H%)!f]zWt  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); `)e5pK  
Utility.log(header+" : "+con.getHeaderField(header));  hUy"XXpr  
else 82ay("ZY  
break; HD^Ou5YB  
} f5p>oXo4b  
} Pi|WOE2  
;"/[gFD5u  
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public void splitterStop() K,f*}1$qM  
{ M*ZR+pq,  
bStop = true; )`;Q]?D   
} c^$_epc*  
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} ;!H<W[  
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/* N]gJ(g  
**FileAccess.java T](N ^P  
*//文件访问(定位，写) }6zo1"  
package NetFox; G Y??q8  
import java.io.*; hRK&  
>fG=(1"  
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public class FileAccessI implements Serializable{ \*] l'>x1  
FvX<(8'#a  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 HLMcOuj  
RandomAccessFile oSavedFile; 5P=3.Mk  
long nPos; OU2.d7  
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public FileAccessI() throws IOException ?\|QDJXY  
{ -J7BEx  
this("",0); ?#N: a  
} >uHU3<2&  
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bs_>!H1  
public FileAccessI(String sName,long nPos) throws IOException Da.eVU;  
{ z$#q'+$  
oSavedFile = new RandomAccessFile(sName,"rw"); 5q<cZ)v#&  
this.nPos = nPos; NXwthc3  
oSavedFile.seek(nPos); \YXzq<7  
} tOUpK20q.@  
i_/
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public synchronized int write(byte[] b,int nStart,int nLen) S5o\joc  
{ 1!N|a< #  
int n = -1; !e>+O^  
try{ )Z4i

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oSavedFile.write(b,nStart,nLen); c*>8VW>  
n = nLen; }STTDq4  
} >4n\  
catch(IOException e) ^,W;d
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{ 5UWj#|t  
e.printStackTrace (); -"Mq<XO&51  
} ].AAHu5  
<Wd#HKIG>l  
h2k"iO}  
return n; 6}z-X*  
} aCxF{>n  
,"6Bw|s  
& OO0v*@{  
} g=G>4Ua3  
@aQ};~  
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/* a^{"E8j  
**SiteInfoBean.java YK xkO  
*/ Ry47Fze  
package NetFox; 
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public class SiteInfoBean { 6&8uLM(z  
~&}e8ah2  
CG[2  
private String sSiteURL; //Site's URL {C>E*qp}f  
private String sFilePath; //Saved File's Path u
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private String sFileName; //Saved File's Name #)3luf3G  
private int nSplitter; //Count of Splited Downloading File HB|R1<t;HB  
7~zd % o  
|B{@noGX  
public SiteInfoBean() fBj-R~;0  
{//nSplitter的缺省值为5 MUQj7.rNa  
//default value of nSplitter is 5 + *xi&|%  
this("","","",5); 
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} e]9Z]a2  
P/!W']OO  
\ 8v^ hb  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qV$\E=%fhM  
{ [SKN}:D  
sSiteURL= sURL; 0Dt-!Q7  
sFilePath = sPath; Ji#eA[  
sFileName = sName; o;[?b'\[d  
this.nSplitter = nSpiltter; u~pBMg ,  
MpNgp)%>  
8-||Nh  
} uM"_3je{W2  
DXI{ jalL  
&~Hx!]uc  
public String getSSiteURL() pie8 3Wy>  
{ Y5fz_ [("  
return sSiteURL; i)!2DXn  
} z=FOymvC  
[_B
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I4"(4u@P  
public void setSSiteURL(String value)  `1`Qu!  
{ 969Y[XQ  
sSiteURL = value; {P{h|+;  
} Tr@|QNu  
GQH15_  
.&i_~?1[N  
public String getSFilePath() @sdHB./  
{ +0l-zd\  
return sFilePath; Q\W?qB_  
} ''Y'ZsQ;  
`R!%k]$  
L*#W?WMM v  
public void setSFilePath(String value) *)Us   
{ 8a8CY,n{  
sFilePath = value; 31GqWN`>$  
} M!Ua/g=u  
_LSp \{Z  
1w!O&kn  
public String getSFileName() jct|}U  
{ Ur9L8EdC  
return sFileName; w/f?KN
  
} ,,c+R?D  
?E}9TQ  
V(5*Dn84  
public void setSFileName(String value) }?)U`zF)7}  
{ kXroFLrY  
sFileName = value; L$z(&%Nx  
} OLZs}N+;]  
h(K}N5`  
ucYweXsO3  
public int getNSplitter() 5W!#,jz  
{ &[z<p  
return nSplitter; WYN0,rv1:+  
} iLt2L;v>h  
j  Gp&P  
 3GL,=q  
public void setNSplitter(int nCount) 3y%,f|ju  
{ LC,6hpmh  
nSplitter = nCount; Bra}HjHO  
} tbXl5x0  
} _)S['[  
()Q#@?c~  
%"Ia]0  
/* 6z5wFzJv?q  
**Utility.java F};T
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*/ P84=.*>  
package NetFox; %-KgR  
w `nm}4M  
T'ei>]y]  
public class Utility { TD sjNFe3  
IhHKRb[  
RT. %\)))  
public Utility() Alk+MwjR  
{ `t"7[Zk  
f>iDqC4  

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} Vq599M:)V  
l* z"wA-  
//线程睡眠 nR=!S5>S  
public static void sleep(int nSecond) USg,=YM  
{ Pj
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try{ 9H/C(Vo  
Thread.sleep(nSecond); GOsOFs"I  
} #p<(2wN  
catch(Exception e) _fdD4-2U  
{ jmG)p|6  
e.printStackTrace (); 9tWpxrig%  
}  (l-l Y  
} ZPG~@lU  
kni{1Gr  
//日志 Iqci}G%r  
public static void log(String sMsg) :*ZijN*{)$  
{ VHi'
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System.err.println(sMsg); *P/DDRq(2  
} S.Q:O{]  
Q?bCQZ{-Lh  
%ol\ sO|  
public static void log(int sMsg) [Z2{S-)UM  
{ mM r$~^P:  
System.err.println(sMsg); ^-Rqlr,F;  
} ^3ai}Ei3  
} 'YJ~~o  
CXBFR>"  
h[;DRD!Z  
/* )KY4BBc  
**TestMethod.java t`Rbn{  
*/ `GSl}A  
package NetFox; qu\U^F  
h$#PboLd  
1En:QQ4/  
public class TestMethod { UIkO_/}  
*a^wYWa  
,9M2'6=  
public TestMethod() :Q,~Nw>  
{ ///xx/weblogic60b2_win.exe @?jbah
#  
try{ ;Y,zlq2  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /BN=Kl]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }G "EdhSl  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5IA
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fileFetch.start(); =w3cF)&  
} e)y+]  
catch(Exception e){e.printStackTrace ();} /#z"c]#  
=te4p@
 
di(H-=9G62  
} r0@s3/  
xSqr=^  
*&tTiv{^  
public static void main(String[] args) a)*(**e$*i  
{ iaJLIrl  
new TestMethod(); E5#ff5  
} \<hHZS  
} l_4^TYF  
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