http断点续传简单实现（java)

/* uv!/DX#  
**SiteFileFetch.java k@'.d)y0`  
*/ huIr*)r&p  
package NetFox; ~5b %~:  
import java.io.*; 7 &Aakl  
import java.net.*; gK'MUZ()  
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public class SiteFileFetch extends Thread { Xs/hqIXB  
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SiteInfoBean siteInfoBean = null; //文件信息Bean \8!HZei  
long[] nStartPos; //开始位置 xAflcY>Ozs  
long[] nEndPos; //结束位置 'I2)-=ZL6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 IcZ'KV  
long nFileLength; //文件长度 NR5A"
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boolean bFirst = true; //是否第一次取文件 [(mq8Nb  
boolean bStop = false; //停止标志 $nW>]S\|  
File tmpFile; //文件下载的临时信息 A 3l1$t#w  
DataOutputStream output; //输出到文件的输出流 4w,}1uNEf  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） !p$V7pFu6  
public SiteFileFetch(SiteInfoBean bean) throws IOException Yu=^`I  
{ {ig@Iy~DT  
siteInfoBean = bean; |j<'[gB\p  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Gmb57z&:  
if(tmpFile.exists ()) t +_G%tv  
{ 6~s,j({^  
bFirst = false; iu .{L(m  
read_nPos(); {mDaK&]Oh  
} 5V0=-K  
else V4>P8cE  
{ 6`i'  
nStartPos = new long[bean.getNSplitter()]; g7pFOcV  
nEndPos = new long[bean.getNSplitter()]; }|d:(*  
} v|xlI4  
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} Smp+}-3O  
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public void run() 19EU[eb  
{ #3S/TBy,  
//获得文件长度 yRtFUlm`  
//分割文件 ]8#{rQ(  
//实例FileSplitterFetch 5^k#
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//启动FileSplitterFetch线程 9fiZ5\  
//等待子线程返回 DEB
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try{ &P;x<7h$t?  
if(bFirst) =YBJ7.Y  
{ I6\3wU~).  
nFileLength = getFileSize(); <j>@Fg#q  
if(nFileLength == -1) ,-Na'n  
{ wcOAyo5(n  
System.err.println("File Length is not known!"); z(xvt>  
} Z6=!}a%  
else if(nFileLength == -2) /H)g<YA  
{ iw{n|&Y#`  
System.err.println("File is not access!"); cA*%K[9  
} /c7j@=0  
else E*%{Nn  
{ k}/: xN"  
for(int i=0;i<nStartPos.length;i++) P/_XDP./U  
{ kU /?#s  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1ysA~2  
} UaBR;v-.B3  
for(int i=0;i<nEndPos.length-1;i++) kBTuM"  
{ b7
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nEndPos = nStartPos[i+1]; `XnFc*L 1  
} }8svd#S+  
nEndPos[nEndPos.length-1] = nFileLength; ns3k{l#  
} oTL "]3`'  
} ,uw&)A  
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//启动子线程 L=$P  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fkYQ3d,`  
for(int i=0;i<nStartPos.length;i++) OV[-m;h|  
{ Zwcb5\Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ovl@[>OB  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), l20q(lb  
nStartPos,nEndPos,i); I}:/v$btM  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OhTO*C8  
fileSplitterFetch.start(); s[g1ei9  
} iPIA&)x}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), wK3}K  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); IoX(Pa  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", L/ZZe5I  
nEndPos = " + nFileLength); #Ky0` n  
// fileSplitterFetch[nPos.length-1].start(); |oM6(px  
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//等待子线程结束 _k}b  
//int count = 0; ("aYjKk  
//是否结束while循环 * n[6H  
boolean breakWhile = false; =:b/z1-v  
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o 2DnkzpJ  
while(!bStop) 1ID!rxE  
{ `8Om*{xg  
write_nPos(); ~$cw]R58,9  
Utility.sleep(500); /oI''O%M  
breakWhile = true; (T^aZuuS  
[7B&<zY/?  
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for(int i=0;i<nStartPos.length;i++) `SVR_  
{ /v8qT'$^  
if(!fileSplitterFetch.bDownOver) 6e*JCf>  
{ Y,a.9AWw)  
breakWhile = false; @.5Ybgn  
break; C/E3NL8  
} H1w;Wb1se  
} +V) (,f1  
if(breakWhile) 4b#YpK$7U  
break; }A#FGH+  
>?kt3.IQ!X  
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//count++; ^8 z*f&g  
//if(count>4) |k)u..k{>  
// siteStop(); CkP!4^J qQ  
} xS.0u"[  
u/MIB`@,  
* T-XslI  
System.err.println("文件下载结束！"); *8Lym,]  
} kTzZj|l^\  
catch(Exception e){e.printStackTrace ();} PvM<#zq_  
} @<YZa$`  
d ][E;$  
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//获得文件长度 iD\joh-C  
public long getFileSize() +EFurdX\  
{ zJ\I%7h*  
int nFileLength = -1; {S}/LSNB  
try{ F[+sc Mx!G  
URL url = new URL(siteInfoBean.getSSiteURL()); )TWf/Lcp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c>
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httpConnection.setRequestProperty("User-Agent","NetFox"); c{E-4PYbah  
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int responseCode=httpConnection.getResponseCode(); aw,8'N)  
if(responseCode>=400) B1GSZUd^?0  
{ )~J/,\  
processErrorCode(responseCode); &K7g8x"x.  
return -2; //-2 represent access is error *Vc}W  
} <sPB|5Ak  
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String sHeader; a{HvrWs?Q  
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)I*V('R6|  
for(int i=1;;i++) 86I".R$d  
{ I[R?j?$}>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); j;'NJ~NZ$  
//Utility.log(in.readLine()); ~
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sHeader=httpConnection.getHeaderFieldKey(i); 6L4B$'&KQZ  
if(sHeader!=null) R&-bA3w$  
{ s0\X%U("  
if(sHeader.equals("Content-Length")) R)H@'X  
{ ~"LOw_BRh  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); dx~F [  
break; 4(Mt6{q  
} |GMK@Q'0:  
} l@^RbF['  
else 2Gj&7A3b  
break; F|"NJ*o}  
} m1frN#3  
} X`22Hf4ct  
catch(IOException e){e.printStackTrace ();} k<St:X%.O  
catch(Exception e){e.printStackTrace ();} 5$y<nMP  
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Utility.log(nFileLength); HezCRtxRcc  
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return nFileLength; `T mIrc  
} wp@c;gK7  
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//保存下载信息（文件指针位置） ?1[go+56X  
private void write_nPos() Wy|=F~N  
{ rm2TWM|  
try{ KLoHjBq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BtjsN22  
output.writeInt(nStartPos.length); pE=wP/#  
for(int i=0;i<nStartPos.length;i++) 8*|
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{ 2Ay2 G-  
// output.writeLong(nPos); q k!Q2W  
output.writeLong(fileSplitterFetch.nStartPos); 7%0PsF _  
output.writeLong(fileSplitterFetch.nEndPos); N!P* B$d  
} ^+}<Q#y-  
output.close(); 8sL7p4  
} F35e/YfG  
catch(IOException e){e.printStackTrace ();} JiRW|+`pe  
catch(Exception e){e.printStackTrace ();} 'vh:(-  
} v!W,h2:J  
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//读取保存的下载信息（文件指针位置）
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private void read_nPos() /at#[Pw~01  
{ }U8H4B~UtY  
try{ +pDuRr  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); XX/cJp  
int nCount = input.readInt(); {gJOc,U4b  
nStartPos = new long[nCount]; d`2VbZC`  
nEndPos = new long[nCount]; %T88K}?=  
for(int i=0;i<nStartPos.length;i++) C=.  
{ bd%/dr  
nStartPos = input.readLong(); h883pe
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nEndPos = input.readLong(); Qx {/izc  
} ptUnV3h  
input.close(); W/+|dN{O+g  
} ql],Wplg  
catch(IOException e){e.printStackTrace ();} !QYqRH~5  
catch(Exception e){e.printStackTrace ();} or(Z-8a_  
} Q~`]0R159e  
(}}BZS&.  
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private void processErrorCode(int nErrorCode) G66vzwO  
{ 6W~F nJI  
System.err.println("Error Code : " + nErrorCode); FzW(An&x2  
} aLP2p
]  
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//停止文件下载 ;zs4>>^>  
public void siteStop() u
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{ Vj`9j. 5  
bStop = true; Z>o20uA  
for(int i=0;i<nStartPos.length;i++) TlM ]d;9G  
fileSplitterFetch.splitterStop(); uYJ6"j  
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} <~f/T]E,  
} 2<<,a
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//负责部分文件的抓取 GT*\gZ  
**FileSplitterFetch.java *-gS u  
*/ 8_W<BXW  
package NetFox; {L3lQ8Z  
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import java.io.*; xUj[d(q  
import java.net.*; x"*u98&3  
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public class FileSplitterFetch extends Thread { 17J|g.]m-&  
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String sURL; //File URL s
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long nStartPos; //File Snippet Start Position 670g|&v.  
long nEndPos; //File Snippet End Position Pgb<;c:4  
int nThreadID; //Thread's ID 1P&c:n  
boolean bDownOver = false; //Downing is over R$NH [Tz  
boolean bStop = false; //Stop identical WCU[]A  
FileAccessI fileAccessI = null; //File Access interface Wrt3p-N"D  
HlLF<k~}  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException o9>r -  
{ ~[l2"@  
this.sURL = sURL; G^oBu^bq~  
this.nStartPos = nStart; Xv6z>z.  
this.nEndPos = nEnd; = R; 0Ed&b  
nThreadID = id; 8!E$0^)c|  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8%2*RKj  
} /1t(e._  
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public void run() 7w YSP&$  
{ q4Qm:|-  
while(nStartPos < nEndPos && !bStop) )k=8.j4  
{ [\eUCt F  
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try{ zN*/G6>A  
URL url = new URL(sURL); (lT H EiX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ME{i-E4  
httpConnection.setRequestProperty("User-Agent","NetFox"); \2pJ ]  
String sProperty = "bytes="+nStartPos+"-"; USJ4qv+-  
httpConnection.setRequestProperty("RANGE",sProperty); hAKyT~[n0  
Utility.log(sProperty); ,~%Qu~\  
-7hU1j~I  
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InputStream input = httpConnection.getInputStream(); I3p ~pt2  
//logResponseHead(httpConnection); 6D@tCmmq  
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byte[] b = new byte[1024]; cBiv=!n  
int nRead; Ond"Eq=r  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R2Lq,(@-  
{ 9kWyO:a_(  
nStartPos += fileAccessI.write(b,0,nRead); f!eC|:D  
//if(nThreadID == 1) >J|I  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {b8!YbG  
} ey@y?X=  
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Utility.log("Thread " + nThreadID + " is over!"); i%D/@$\D6  
bDownOver = true; vUY?Eb[  
//nPos = fileAccessI.write (b,0,nRead); A<QYW,:|  
} )k- 7mwkZ  
catch(Exception e){e.printStackTrace ();} VNx}ADXu]  
} e*:[#LJ]C  
} a:7"F{D91  
,`B*rCOa  
')}$v+9h  
//打印回应的头信息 0A/GWSmF  
public void logResponseHead(HttpURLConnection con) >pT92VN  
{ ` L6H2:pf  
for(int i=1;;i++) ^7vhize  
{ rmk'{"  
String header=con.getHeaderFieldKey(i); R1\cAP^0  
if(header!=null) Y:ZI9JK?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); X_
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Utility.log(header+" : "+con.getHeaderField(header)); ;xXHSxa:=W  
else b8feo'4Z   
break; #AFr@n  
} MuO7_*q'n  
} `LVXK|m+$  
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#$e~o}(r  
public void splitterStop() Z#3wMK~  
{ 76 #  
bStop = true; yAi#Y3!::  
} p$0;~1vH  
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} EAqTXB@XU  
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/* &:nWZ!D  
**FileAccess.java mAX]m1s  
*//文件访问(定位，写) )U`H7\*)  
package NetFox; fI t:eKHr  
import java.io.*; s"=e(ob  
\b1I<4(  
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public class FileAccessI implements Serializable{ 69`9!heu  
>OBuHqC  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 U3&*,xeU@H  
RandomAccessFile oSavedFile; I^qk`5w  
long nPos; /1gKc}rB2  
7=6p  
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public FileAccessI() throws IOException xEOR\(Z^  
{ A!ba_14  
this("",0); N`Zm[Sv7  
} >Czcs=(L.k  
= K"F!}  
s@'};E^]@r  
public FileAccessI(String sName,long nPos) throws IOException gOx4qxy/m|  
{ 4&R\6!*s  
oSavedFile = new RandomAccessFile(sName,"rw"); Cc1sZWvz  
this.nPos = nPos; P zzX Ds6  
oSavedFile.seek(nPos); e-]k{_wm  
} (b GiBsb  
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i/,G=yA  
public synchronized int write(byte[] b,int nStart,int nLen) VX[{X8PkS  
{ ? Ls]k  
int n = -1; 3|[:8  
try{ P(VQD>G  
oSavedFile.write(b,nStart,nLen); >6@*%LM  
n = nLen; "a?k #!E  
} 3BKW  
catch(IOException e) Ad+-/hxc
 
{ Ra;e#)7X  
e.printStackTrace (); QtW5;A-h  
} /ZvNgaH5M  
hOO)0IrIM*  
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return n; /d0LD  
} ahhVl=9/ao  
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#D .H2'_}  
} <T+Pw7X   
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X:j&+d2g0/  
/* ?P4`  
**SiteInfoBean.java jQ4Pv`  
*/ =3a`NO5!  
package NetFox; H) m!)=\'  
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) ok_"wB  
public class SiteInfoBean { tJ&S&[}  
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Oa$ew'  
private String sSiteURL; //Site's URL IgLP=mqcWK  
private String sFilePath; //Saved File's Path gA`/t e  
private String sFileName; //Saved File's Name ?F(t`0=  
private int nSplitter; //Count of Splited Downloading File MP w@O0QS  
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public SiteInfoBean() 4Qz  
{//nSplitter的缺省值为5 [j1SX-NX  
//default value of nSplitter is 5 7`~h'(k  
this("","","",5); KG4~t=J`  
} ;k (}~_  
t1n'
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) GNZQj8  
{ shYcfLJ  
sSiteURL= sURL; N{q5E,}  
sFilePath = sPath; '"GdO;}&  
sFileName = sName; 6
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this.nSplitter = nSpiltter; 0 -=onX  
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} bpzB}nEp  
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public String getSSiteURL() -x:Wp*,  
{ f2uog$Hk  
return sSiteURL; (|(Y;%>-v  
} ;}.jRmnJ  
+ulX(u(,  
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public void setSSiteURL(String value) %vxd($Ti"  
{ 1Q#hanh_`  
sSiteURL = value; ?9Fv0-g&n  
} 9P{5bG0o8  
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public String getSFilePath() lBD{)Va  
{ yE{l Xp;  
return sFilePath; zp% MK+x  
} t=xO12Z  
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public void setSFilePath(String value) 3|/ ;`KfQ  
{ jdXkU  
sFilePath = value; /n@_Ihx  
} e}(.u1  
*q|.H9 K(  
%
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public String getSFileName() gS4K](KH |  
{ :}+U?8/"7  
return sFileName; IR5 S-vO  
} $daI++v`  
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public void setSFileName(String value) X H{5E4P  
{ &7E0H{  
sFileName = value; MCz+l0  
} 8%arA"#S  
\8ulX>]  
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public int getNSplitter() 6;*tw i  
{ @#*B|lHE  
return nSplitter; B&-;w_K  
} D 67H56[  
?#,\,  
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public void setNSplitter(int nCount) VF<{Qx*  
{ B,e@v2jO|  
nSplitter = nCount; j(va#f#  
} z<: 9,wtbP  
} [MFV:Z  
P@k ;Lg"  
*Ty>-aS1  
/* :3Ty%W&&  
**Utility.java {D1=TTr^  
*/ B 8C3LP}?  
package NetFox; {7Dc(gNS  
i
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public class Utility { IBES$[  
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public Utility() FRs5 Pb1  
{ d<`Z{"g NS  
{3_M&$jN  
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} H{p+gj^J  
x*Z"
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//线程睡眠 P1TLH2)  
public static void sleep(int nSecond) `\e@O#,^yI  
{ G]QD6b9~  
try{ ;d?4phl-.  
Thread.sleep(nSecond); khjW9Aa8t  
} T(J&v|FK  
catch(Exception e) gbXzD`WQ  
{ BCsW03sQ  
e.printStackTrace (); 90K&s#+13  
} _$i9Tk
 
} EBK\.[  
R0oP#
#]  
//日志 @>X."QbE  
public static void log(String sMsg) &EA4`p  
{ )oAK)e  
System.err.println(sMsg); pf] sL/g  
} Kc{fT^E  
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i`Lt=)@&  
public static void log(int sMsg) AHn^^'&
x[  
{ s)~Q@ze2  
System.err.println(sMsg); _F,@mQ$!  
} 7F)HAbIS  
} h %MPppCEa  
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/* Nl;rg*@o  
**TestMethod.java Nm#KHA='Z  
*/ *(D_g!a  
package NetFox; CFRo>G  
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public class TestMethod { ;9B:E"K?@1  
}6^(  
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public TestMethod() Q'$aFl'NR  
{ ///xx/weblogic60b2_win.exe zzq/%jki  
try{ ?w3f;v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ymr-kB  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); G78rpp  
SiteFileFetch fileFetch = new SiteFileFetch(bean); l}:9)nXA
{  
fileFetch.start(); ~[ve?51  
} cJi5\<b  
catch(Exception e){e.printStackTrace ();} //V?rs  
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;}^Pfm8  
} J~n{gT<L  
'T+3tGCy+  
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public static void main(String[] args) NrS1y"#d9  
{ 3YA !2  
new TestMethod(); urXM}^  
} ?\ho9nyK  
} |W\CV0L2  
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