http断点续传简单实现（java)

/* ]oeuIRyQ  
**SiteFileFetch.java !/6\m!e|1R  
*/ K6v $#{$6  
package NetFox; $xA J9_2P  
import java.io.*; n^AP"1l8?0  
import java.net.*; xY2}Wr j,  
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public class SiteFileFetch extends Thread { 3WCqKXJ7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean W(2+z5z  
long[] nStartPos; //开始位置 @A2/@]HBm  
long[] nEndPos; //结束位置 M'umoZmW0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 z1f^p7$M?  
long nFileLength; //文件长度 .]j#y9>&w%  
boolean bFirst = true; //是否第一次取文件 _{e&@d  
boolean bStop = false; //停止标志 }dX/Y/  
File tmpFile; //文件下载的临时信息 [,<\RviI  
DataOutputStream output; //输出到文件的输出流 g\o{}Q%X  
}X
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 'Aj(i/CM  
public SiteFileFetch(SiteInfoBean bean) throws IOException l:Dn3Q  
{ -DP8NTl"  
siteInfoBean = bean; b/sOfQ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); <i}q=%W!1  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ap]4QqU  
if(tmpFile.exists ()) 4,2(nYF  
{ |*:tyP%m^  
bFirst = false; i90}Xyt  
read_nPos(); tXt:HVN  
} >;)2NrJV  
else %yp5DD}|  
{ 9#uIC7M  
nStartPos = new long[bean.getNSplitter()]; wW-Ab  
nEndPos = new long[bean.getNSplitter()]; 2\VAmPG.Zs  
} N31?9GE  
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} LfEvc2 v=g  
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9 ~~qAoD  
public void run() ~\$=w10  
{ /|GT\X4o  
//获得文件长度 \eQla8s  
//分割文件 wepwXy"  
//实例FileSplitterFetch Sk\n;mL:  
//启动FileSplitterFetch线程 r} Lb3`'  
//等待子线程返回 3cqQL!Gm  
try{ }f#_4ACaD  
if(bFirst) 3?2<WEYr  
{ 0x@A~!MoP  
nFileLength = getFileSize(); j$Nf%V 6Y  
if(nFileLength == -1) ~wOTjz  
{  `?|Rc  
System.err.println("File Length is not known!"); w$j{Hp6m  
} >GXXjAIu/  
else if(nFileLength == -2) &~ *.CQa  
{ 9_ZBV{   
System.err.println("File is not access!"); q\Rq!7(  
} jH>8bXQqZ  
else r?p[3JJ;mG  
{ BC! 6O/
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for(int i=0;i<nStartPos.length;i++) vT c7an6fy  
{ v^SsoX>WMH  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); d yh<pX/$  
} o5swH6Y.)J  
for(int i=0;i<nEndPos.length-1;i++) pY
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{ i%;"[M  
nEndPos = nStartPos[i+1]; nBz`q+V  
} I{ ryD -!  
nEndPos[nEndPos.length-1] = nFileLength; GqLq gns  
} 5Fbs WW2  
} 53Yxz3v  
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//启动子线程 raE Mm  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Qz,|mo+  
for(int i=0;i<nStartPos.length;i++) 3[d>&xk@$  
{ sw;|'N$:<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n2f6p<8A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #.._c?%4/  
nStartPos,nEndPos,i); UDEj[12S  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M`7y>Ud  
fileSplitterFetch.start(); kWhr1wR1  
} ?9mkRd}c  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3qaMO#{
M  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -Z0+oU(?YE  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Xg7|JS!  
nEndPos = " + nFileLength); 5~H#(d<oZ  
// fileSplitterFetch[nPos.length-1].start(); "m$3)7 $  
$s-Y%gc  
YKZa$@fA?  
//等待子线程结束 >Cr\y  
//int count = 0; 2`?!+")  
//是否结束while循环 y_p.Gzy(^}  
boolean breakWhile = false; u92^(|  
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while(!bStop) S
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{ x=q;O+7]  
write_nPos(); r;&>iX4B  
Utility.sleep(500); T
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breakWhile = true; 2]cRXJ7h  
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for(int i=0;i<nStartPos.length;i++) m ci/'b Xt  
{ 2`GOJ,$  
if(!fileSplitterFetch.bDownOver) a^U~0i@[S  
{ 8s{?v&p  
breakWhile = false; _)T5lEFl=  
break; ^T::-pN*  
} 'cix`l|^  
} 06q(aI^Ch@  
if(breakWhile) 6( CDNMzj  
break; BZ!v%4^9  
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//count++; !K f#@0E..  
//if(count>4) eqw0]U\pv  
// siteStop(); ?W^c4NtP  
} y*pUlts<  
!$-\;<bZw  
fC
,:{}  
System.err.println("文件下载结束！"); li~d?>  
} ia\eLzj  
catch(Exception e){e.printStackTrace ();} =U%Rvm  
} 3b'QLfU&#  
>Cw<BIF  
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//获得文件长度 QnZcBXI8  
public long getFileSize() )E@A0W  
{ ),G=s Oo  
int nFileLength = -1; b2b^1{@h;v  
try{ Tq]Sn]CSP  
URL url = new URL(siteInfoBean.getSSiteURL()); 79`AM X[b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^6_e=jIN  
httpConnection.setRequestProperty("User-Agent","NetFox"); *s9C!wYMZ  
S S2FTb-m  

> ;/l)qk,  
int responseCode=httpConnection.getResponseCode(); rM'=_nmi  
if(responseCode>=400) _%5Ro6  
{ ~//fN}~R  
processErrorCode(responseCode);  IiY/(N+J  
return -2; //-2 represent access is error C(
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} b0lq\9  
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String sHeader; .Fdgb4>BXX  
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for(int i=1;;i++) {NHdyc$  
{ spt6]"Ni  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); XUz3*rfs  
//Utility.log(in.readLine()); <YdE1{fm  
sHeader=httpConnection.getHeaderFieldKey(i); 9I6
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if(sHeader!=null) !\7!3$w'8,  
{ _d5QbTe  
if(sHeader.equals("Content-Length")) \ExMk<y_&  
{ wK?vPS  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u6AA4(  
break; U4d:] z  
} L7dd(^  
} wne,e's}   
else gt@m?w(  
break; wOU_*uY@6'  
} RW<D<5C  
} A
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catch(IOException e){e.printStackTrace ();} sS*3=Yh  
catch(Exception e){e.printStackTrace ();} |olA9mp|]  
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Utility.log(nFileLength); 4y|BOVl  
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return nFileLength; ;ub;lh3  
} ZrpU <   
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//保存下载信息（文件指针位置） |-:()yxs  
private void write_nPos() -|$@-
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{ 8\+uec]k  
try{ Lt64JH^lz  
output = new DataOutputStream(new FileOutputStream(tmpFile)); rNXQf'*I  
output.writeInt(nStartPos.length); xF!,IKlBBp  
for(int i=0;i<nStartPos.length;i++) "\:`/k3  
{ 9X}10u:  
// output.writeLong(nPos); +$ 'Zf0U  
output.writeLong(fileSplitterFetch.nStartPos); p`olCp'  
output.writeLong(fileSplitterFetch.nEndPos); .*OdqLz  
} ]L5@,E4.  
output.close(); 3lrT3a3vV  
} <cps2*'  
catch(IOException e){e.printStackTrace ();} (KjoSN( K  
catch(Exception e){e.printStackTrace ();} 9+Np4i@  
} n(1l}TJy  
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//读取保存的下载信息（文件指针位置） "q3ZWNS'w  
private void read_nPos()
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{ *& BQTZ6  
try{ ?1~`*LE  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Vh|*p&  
int nCount = input.readInt(); f z'@_4hg  
nStartPos = new long[nCount]; |mZxfI  
nEndPos = new long[nCount]; p$S*dr  
for(int i=0;i<nStartPos.length;i++) `KZm0d{H  
{ zfJ
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nStartPos = input.readLong();
x]}^v#  
nEndPos = input.readLong(); zVViLUwG  
} x[ SDl(<@;  
input.close(); w'>pY  
} Zu*F#s!tUI  
catch(IOException e){e.printStackTrace ();} ">\?&0  
catch(Exception e){e.printStackTrace ();} S,88*F(<^q  
} (>LF(ll  
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private void processErrorCode(int nErrorCode) \[;0KV_  
{ k$n|*kCh  
System.err.println("Error Code : " + nErrorCode); )*u8/U  
} &h}#HS>l  
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//停止文件下载 akmkyrz'&  
public void siteStop() =O~_Q-  
{ f[]dfLS"W  
bStop = true; x`mG<Yt
 
for(int i=0;i<nStartPos.length;i++) p'Y^X  
fileSplitterFetch.splitterStop(); ]}V<*f  
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} ko!)s  
} !hm]fh_j  
//负责部分文件的抓取 T~-ycVc  
**FileSplitterFetch.java irZ]
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*/ ez7A4>
/  
package NetFox; aEB_#1  
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import java.io.*; sWhZby7  
import java.net.*; o
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public class FileSplitterFetch extends Thread { W"scV@HKu  
<NMEGit  
_T60;ZI+^  
String sURL; //File URL ;[ZEDF5H  
long nStartPos; //File Snippet Start Position IW5,
7.  
long nEndPos; //File Snippet End Position ,CJWO bn3  
int nThreadID; //Thread's ID Zpt\p7WQ  
boolean bDownOver = false; //Downing is over 6bg ;q(*7  
boolean bStop = false; //Stop identical b1I]>\  
FileAccessI fileAccessI = null; //File Access interface aj='b.2)  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException L;z?aZ7n  
{ iqsCB%;5  
this.sURL = sURL; A`%k:@  
this.nStartPos = nStart; MpT8" /.]A  
this.nEndPos = nEnd; h4gXvPS&r  
nThreadID = id; iI T;K@&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ScOK)nL"  
} H*n-_{h"t  
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9cbd~mM{  
public void run() :U|1xgB  
{ kt#fMd$  
while(nStartPos < nEndPos && !bStop) K-)] 1BG  
{ J3V= 46Yc  
;?Tbnn Wn  
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try{ 5Pc;5 o0C  
URL url = new URL(sURL); Qp5VP@t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); C}j"Qi`  
httpConnection.setRequestProperty("User-Agent","NetFox"); K!%+0)A  
String sProperty = "bytes="+nStartPos+"-"; o'aEY<mZ7  
httpConnection.setRequestProperty("RANGE",sProperty); 2QcOR4_V  
Utility.log(sProperty); !qQl@jO  
/{J4:N'B>  
) w5SUb  
InputStream input = httpConnection.getInputStream(); eb\K "ec"  
//logResponseHead(httpConnection); L[fiU0^o  
!
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byte[] b = new byte[1024]; O/(`S<iip  
int nRead; t>RY7C;PuS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3pROf#M  
{ xIW3={b3  
nStartPos += fileAccessI.write(b,0,nRead); sE<V5`Z=  
//if(nThreadID == 1) H2 {+)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Et_bH%0  
} |^I0dR/w:  
76Cl\r
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2zA4vZkbcw  
Utility.log("Thread " + nThreadID + " is over!"); ,-LwtePJ0  
bDownOver = true; Rok7n1gW  
//nPos = fileAccessI.write (b,0,nRead); B]wk+8SMY.  
} qr^3R&z!}  
catch(Exception e){e.printStackTrace ();}

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} x+:UN'
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} <al(7  
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^mDe08. %b  
//打印回应的头信息 Zn+.
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public void logResponseHead(HttpURLConnection con) u%KTNa0  
{ 5lmHotj#  
for(int i=1;;i++) =:Fc;n>c<K  
{ AT
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String header=con.getHeaderFieldKey(i); %lhEM}Sm  
if(header!=null) CyFrb`%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); jD]~ AwRJ  
Utility.log(header+" : "+con.getHeaderField(header)); .V/Rfq  
else #U4F0BdA  
break; iN\4gQ!  
} rQs)O<jl  
} #4%]o%.  
%P/Jq#FE.  
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public void splitterStop() ]i)c{y  
{ BwGfTua  
bStop = true; #aJ(m&  
} . B9iLI  
drP=A~?&:  
~9]hV7y5C  
} |Nn)m  
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/* 0
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**FileAccess.java $E~`\o%Ev  
*//文件访问(定位，写) X,_2FJv  
package NetFox; *[Tz![|  
import java.io.*; Egp/f|y  
H>IMf/%5N-  
c /HHy,  
public class FileAccessI implements Serializable{
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g`' !HGY  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C.yQ=\U2  
RandomAccessFile oSavedFile; b\kdKVh&  
long nPos; DDP/DD;n}r  
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public FileAccessI() throws IOException x(6SG+Kr  
{ gnOt+W8  
this("",0); Nho>f  
} /<=u\e'rE  
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public FileAccessI(String sName,long nPos) throws IOException JN-y)L/>  
{ %KlrSo  
oSavedFile = new RandomAccessFile(sName,"rw"); uK"=i8rs4  
this.nPos = nPos; Z, Yb&b  
oSavedFile.seek(nPos); s4y73-J^.v  
} |`2RShu  
1~Y<//5E  
{9&;Q|D z  
public synchronized int write(byte[] b,int nStart,int nLen) M
#4pE_G  
{ .\ULbN3Z  
int n = -1; Eex~xiiV  
try{ nLZTK&7}  
oSavedFile.write(b,nStart,nLen); )Xz,j9GzJS  
n = nLen; O>bC2;+s  
} #4Rx]zW^%  
catch(IOException e) Ar
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{ a od-3"7[  
e.printStackTrace (); )hn6sXo+  
} X"|['t  
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return n; <sGVR5NR  
} ]b:Lo  
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} P:K5",)  
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pSH
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/* ;s= l52  
**SiteInfoBean.java i4Q@K,$  
*/ b5dD/-Vj  
package NetFox; $kdB |4C  
7?!d^$B  
93
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public class SiteInfoBean { >-RQ]?^  
lBLARz&c#  
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private String sSiteURL; //Site's URL UawyDs  
private String sFilePath; //Saved File's Path
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private String sFileName; //Saved File's Name Wq D4YGN  
private int nSplitter; //Count of Splited Downloading File R6<X%*&%  
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@|Cz-J;D  
public SiteInfoBean() 6m/r+?'  
{//nSplitter的缺省值为5 1Z/(G1  
//default value of nSplitter is 5 u OmtyX  
this("","","",5); gS!:+G%  
} a_^\=&?'  
kr^P6}'  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) kUL'1!j7  
{ 8rAg\H3E  
sSiteURL= sURL; ?um;s-x)  
sFilePath = sPath; 

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sFileName = sName; q<x/Hat)  
this.nSplitter = nSpiltter; #X+JHl  
IEL%!RFG  
j1Y~_  
} 6IN e@  
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public String getSSiteURL() >mbHy<<  
{ k$^UUo6  
return sSiteURL; 9R!atPz9  
} CCs%%U/=  
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{ T/[cu<  
public void setSSiteURL(String value) @o].He@L<j  
{ ueogaifvB  
sSiteURL = value; 5ORo3T%  
} ]? c B:}  
g.
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public String getSFilePath() 0Uz"^xO["  
{ C!O0xhs  
return sFilePath; LRxZcxmy  
} dohA0  
~Py`P'+  
 \{_q.;}  
public void setSFilePath(String value) ~f2z]JLr:  
{ SBu"3ym  
sFilePath = value; YsC>i`n9  
} tH@Erh|%  
l ~"^7H?4e  
olB.*#gA  
public String getSFileName() 1/B>XkCJ  
{ G<zwv3  
return sFileName; 6D;Sgc5"  
} }^WdJd]P  
d UE,U=  
3Y4?CM&0v  
public void setSFileName(String value) ](]i 'fE>  
{ R{`(c/%8  
sFileName = value; D(op)]8  
} H064BM  
>{n,L6_t  
.^33MWu6  
public int getNSplitter() |)DGkOtd  
{ |*eZD-f  
return nSplitter; !RS}NS  
} VR8-&N  
;W )Y OT  
#powub  
public void setNSplitter(int nCount) ~8Fk(E_  
{ Z9ZPr?C=  
nSplitter = nCount; =_*Zn(>t`  
} *!t/"b
  
} ;u ({\K
 
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oG?Xk%7&\  
/* 9!\B6=r y4  
**Utility.java SYJD?&C;  
*/ #$07:UJ  
package NetFox; 9d659iC  
UYJZYP%r  
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public class Utility { %3-y[f  
WIxy}3_to  
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public Utility() L|7R9+ZG  
{ `i*E~'  
n0 {i&[I~+  
&)ChQZA  
} u'DRN,h+  
}@+0/W?\.  
//线程睡眠 j{A y\n(  
public static void sleep(int nSecond) 8qTys8  
{ ^"2J]&x`G  
try{ @o _}g !9=  
Thread.sleep(nSecond); Rtl"Ub@HV  
} WX?IYQ+  
catch(Exception e) Y"aJur=`  
{ K7:)nv E  
e.printStackTrace (); )9`qG:b'  
} kJsN|
=  
} xF'EiX~  
pJ"qu,w  
//日志 aP+X}r  
public static void log(String sMsg) )~JHgl  
{ 6j]0R*B7`Q  
System.err.println(sMsg); u0c1:Uv#~e  
} K`zdc`/  
Fj3a.'  
c9u`!'g`i  
public static void log(int sMsg) {@{']Y  
{ |FZ/[9*  
System.err.println(sMsg); k9
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} ,Uqs1#r  
} `0gyr(fES  
:bq8N@P/  
A[{yCn`tM  
/* F/kWHVHU[  
**TestMethod.java 29
] G^f>  
*/ 0-Ku7<a  
package NetFox; >jLY"  
G}raA%  
|3"KK  
public class TestMethod { 8dIgjQX|  
-zeG1gr3  
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public TestMethod() Moza".fiN  
{ ///xx/weblogic60b2_win.exe J<h$ wM  
try{ rw JIx|(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); jLm ;ty2;  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); B%6)}Nl[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3bH'H*2  
fileFetch.start();
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} /7F:T[  
catch(Exception e){e.printStackTrace ();} E*K;H8}s  
7[XRd9a5(  
=-n}[Y}A  
} uHzU-FZ|B  
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public static void main(String[] args) '7@zGk##(  
{ }WXi$(@v  
new TestMethod(); `|&O*`  
} ;iL#7NG-R  
} K1yzD6[eW  
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