http断点续传简单实现（java)

/* v?h#Ym3e<  
**SiteFileFetch.java Q:kpaMA1P  
*/ Vv=d*  
package NetFox; n2Ycq&O  
import java.io.*; qdj,Qz9ly  
import java.net.*; K$' J:{yY  
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public class SiteFileFetch extends Thread { )n
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SiteInfoBean siteInfoBean = null; //文件信息Bean {v]A`u)  
long[] nStartPos; //开始位置 c+|,2e 0T  
long[] nEndPos; //结束位置 %qfEFhRC  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >48zRi\N  
long nFileLength; //文件长度 I#S6k%-'  
boolean bFirst = true; //是否第一次取文件 0Km{fZYq7;  
boolean bStop = false; //停止标志 {?BxVDD07  
File tmpFile; //文件下载的临时信息 |'=R`@w~0  
DataOutputStream output; //输出到文件的输出流 2lHJ&fck<  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） O&\;BF5:R  
public SiteFileFetch(SiteInfoBean bean) throws IOException W/{HZ<:.  
{ +l&ZN\@0X  
siteInfoBean = bean; WZ"x\K-;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [al$7R&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 4( ^Ht  
if(tmpFile.exists ()) ,n~H]66n  
{ A*
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bFirst = false; &gcKv1a\  
read_nPos(); x8gUP  
} zj`!ZY?fv  
else ]X4A)%i  
{ oe4Fy}Y_;  
nStartPos = new long[bean.getNSplitter()]; UG48g}  
nEndPos = new long[bean.getNSplitter()]; ,p>=WX  
} .azdAq'r&\  
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} )UZ 's>O  
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public void run() ],&WA?>G  
{ hq$:62NYg  
//获得文件长度 2Wq)y1R<T  
//分割文件 qeSxE`E"  
//实例FileSplitterFetch Uq0RJ<n  
//启动FileSplitterFetch线程 JyYg)f  
//等待子线程返回 8KT|ixs  
try{ m[Px|A5{  
if(bFirst) x"5/1b3aq  
{ XrtB&h|C  
nFileLength = getFileSize(); }N*6xr*X+  
if(nFileLength == -1) tX&
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{ {&"rv<p  
System.err.println("File Length is not known!"); +'hcFZn(T  
} p@NE^aMn  
else if(nFileLength == -2) W9{6?,]  
{ *#+XfOtF  
System.err.println("File is not access!"); |AuN5|obI  
} ?fc({zb  
else a` 95eL}  
{ .0cm mpUNq  
for(int i=0;i<nStartPos.length;i++) wp-*S}TT  
{ B.;/N220P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !ZD[ $lt+  
} eB<R@a|?S  
for(int i=0;i<nEndPos.length-1;i++) /)MzF6  
{ J/M1#sE  
nEndPos = nStartPos[i+1]; kiZA$:V8  
} AAxY{Z-4  
nEndPos[nEndPos.length-1] = nFileLength; t!AHTtI  
} `8KWZi4 ]  
} )#9/vIQ  
b,$H!V*  
#ZRQVC;b;  
//启动子线程 ul>$vUbyf  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G?8LYg!-  
for(int i=0;i<nStartPos.length;i++) 8@|+-)t  
{ [&j!g  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), j#9p0[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), | ?~-k[|  
nStartPos,nEndPos,i); |Ah26<&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); tB'F`HM:mq  
fileSplitterFetch.start(); ~aNK)<Fznd  
} [l:3F<M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), uqnoE;57^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); IFH%R>={  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", |k{?\(h;  
nEndPos = " + nFileLength); q4|TwRx
~  
// fileSplitterFetch[nPos.length-1].start(); mfIY7DP  
Nf%jLK~  
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//等待子线程结束 i_)j K  
//int count = 0; NELQo#kjZ  
//是否结束while循环 1K"``EvNB  
boolean breakWhile = false; KFkKr>S:  
"$;=8O5O  
5qGRz"\p~  
while(!bStop) W> s@fN9  
{ Y<#WC#3=  
write_nPos(); s3W35S0Q3  
Utility.sleep(500); PBTGN;y  
breakWhile = true; h$_Wh(  
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for(int i=0;i<nStartPos.length;i++) l=`)yc.  
{ ;l[/<
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if(!fileSplitterFetch.bDownOver) K@Twiw~rB  
{ KCGs*kp>  
breakWhile = false; /iQ}DbtRb  
break; &G@(f=  
} Y [0S  
} BBm.;=8@ ^  
if(breakWhile) <fCgU&  
break; $h`?l$jC(@  
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{l-,Jbfi`  
//count++; jX$TiG  
//if(count>4) `^-?yu@  
// siteStop(); |qE"60&"}  
} WOZf4X`[  
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System.err.println("文件下载结束！"); _Z~wpO}/  
} f9cS^v_:  
catch(Exception e){e.printStackTrace ();} R|Z$aHQ  
} E<1^i;F  
!:,d^L!bh  
is}o5\JEL  
//获得文件长度 NDm@\<MIzB  
public long getFileSize() 5H1SC8+B,  
{ IpXg2QbN  
int nFileLength = -1; %qcBM~efT  
try{ OY*BVJ^  
URL url = new URL(siteInfoBean.getSSiteURL());  L,!Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a\$PqOB!  
httpConnection.setRequestProperty("User-Agent","NetFox"); +[V[{n  
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int responseCode=httpConnection.getResponseCode(); L[)+J2_<  
if(responseCode>=400) 2T<QG>;)j  
{ URck#5  
processErrorCode(responseCode); "!i7U2M'  
return -2; //-2 represent access is error :c"J$wT/  
} c2Ua!p(c  
I1=YSi;A  
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String sHeader; 6A7UW7/  
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for(int i=1;;i++) 2mP| hp?  
{ /7De.O~H  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ?d-(M' v.  
//Utility.log(in.readLine()); dGAthbWJ  
sHeader=httpConnection.getHeaderFieldKey(i); l7Y^C1hM
 
if(sHeader!=null) !!E_WDZ#9  
{ [-bL>8  
if(sHeader.equals("Content-Length")) W1$B6+}Z0V  
{ w:I^iI.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); sTU]ntoQqR  
break; 6cp x1y]~6  
} ={ c=8G8T  
} XL_X0(AKf  
else "5BgajrB  
break; eC%.xu^  
} Zk$AAjC&  
} ZalG/PFy  
catch(IOException e){e.printStackTrace ();} 1wmS?  
catch(Exception e){e.printStackTrace ();} .Ej `!  
}r3, fH  
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Utility.log(nFileLength); ~j" aJ /  
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return nFileLength; m1a0uEA G  
} AGQCk*dm  
,Ej2]iO\7  
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//保存下载信息（文件指针位置） di]z  
private void write_nPos() zNuiBLxDs  
{ E)o/C(g  
try{ HuBG?4Qd  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &NZN_%  
output.writeInt(nStartPos.length); r
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for(int i=0;i<nStartPos.length;i++) s$YKdtR  
{ 3}= .7qm  
// output.writeLong(nPos); 1eZ">,F6<  
output.writeLong(fileSplitterFetch.nStartPos); ?^mgK9^v@  
output.writeLong(fileSplitterFetch.nEndPos); T5)Xl'Q  
}  V7%G?  
output.close(); C(b"0>  
} qEX2K^y'4"  
catch(IOException e){e.printStackTrace ();} GeWB"(t  
catch(Exception e){e.printStackTrace ();} 1GN>,Lb:o  
} [bUM x  
LN ]ks)  
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//读取保存的下载信息（文件指针位置） ag]b]K  
private void read_nPos() \v44Vmfz  
{ "B*a| 'n!  
try{ 'Sppm;?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F\Q)l+c  
int nCount = input.readInt(); @/l
{  
nStartPos = new long[nCount]; fc._*y#AS  
nEndPos = new long[nCount]; #`RYKQwB  
for(int i=0;i<nStartPos.length;i++) \xkLI:*\  
{ ~mOGNf?f  
nStartPos = input.readLong(); 8 Mp2MZ*p  
nEndPos = input.readLong(); -Cd4yWkO  
} 8[Cp  
input.close(); 25BW/23}e  
} Q2cF++Q1  
catch(IOException e){e.printStackTrace ();} &{9'ylv-B)  
catch(Exception e){e.printStackTrace ();} LG'JQGl5  
} U8]L3&~  
n{d}]V@  
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private void processErrorCode(int nErrorCode) !;{@O`j?b  
{ QIQB  
System.err.println("Error Code : " + nErrorCode); >&
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} wXPNfV<(2  
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3H%R`ha
  
//停止文件下载 jWLZ!a3+  
public void siteStop() .{`+bT^b<2  
{ *yKsgH  
bStop = true; R?qVFMQ  
for(int i=0;i<nStartPos.length;i++) jFM8dl n  
fileSplitterFetch.splitterStop(); 0aQtJ0e16  
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} #pBAGm3  
} @g9j+DcU  
//负责部分文件的抓取 ;38W41d{  
**FileSplitterFetch.java 7Ro7/PT(  
*/ H$KE*Wwq  
package NetFox; Fx4
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import java.io.*; z{d],M  
import java.net.*; 1iS9f~  
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public class FileSplitterFetch extends Thread { auAST;"Z8  
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String sURL; //File URL +cvz  
long nStartPos; //File Snippet Start Position GsqR8n=  
long nEndPos; //File Snippet End Position x,E#+ m  
int nThreadID; //Thread's ID cBmo#:>'  
boolean bDownOver = false; //Downing is over (6A>:_)  
boolean bStop = false; //Stop identical  twz  
FileAccessI fileAccessI = null; //File Access interface l~Kn-S{  
&UP@Sr0D7  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException AJ2Xq*
fk  
{ B h@R9O<  
this.sURL = sURL; HB{-^9{E  
this.nStartPos = nStart; |}^[f]  
this.nEndPos = nEnd; 6R%c+ok8i  
nThreadID = id; EAF<PMb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 I|RN/RVN  
} !s.G$ JS<  
$JqdI/
s  
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public void run() [T"oqO4%]  
{ Vm'ReH  
while(nStartPos < nEndPos && !bStop) >ly= O  
{ j:"+/5rV8  
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try{ [4 g5{eX  
URL url = new URL(sURL); .2Q`. o)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `PSr64h
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httpConnection.setRequestProperty("User-Agent","NetFox"); Y((z9-`  
String sProperty = "bytes="+nStartPos+"-"; *u>2"!+Ob  
httpConnection.setRequestProperty("RANGE",sProperty); E?y0UD[8J  
Utility.log(sProperty); NhCO C  
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InputStream input = httpConnection.getInputStream(); K).X=2gjY  
//logResponseHead(httpConnection); 6'(5pt  
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byte[] b = new byte[1024]; :|<D(YA  
int nRead; lcJ`OLG  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ll1?I8}5|  
{ J4j?rLR3p  
nStartPos += fileAccessI.write(b,0,nRead); ;&
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//if(nThreadID == 1) }tft@,dIC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [H0jDbN  
} tFwQ /  
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"M7ry9dDH  
Utility.log("Thread " + nThreadID + " is over!"); Lr)h>j6\  
bDownOver = true; hz Vpv,|G  
//nPos = fileAccessI.write (b,0,nRead); PHDKx+$  
} s[n
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catch(Exception e){e.printStackTrace ();} $7TY
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} uP|AP  
} Vt n$*ML  
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~#I1!y~`  
//打印回应的头信息 g.DgJX&i  
public void logResponseHead(HttpURLConnection con) Xe=@I*  
{ U~Ni2|}\C9  
for(int i=1;;i++) L$ ]D&f8:  
{ uAzVa!)  
String header=con.getHeaderFieldKey(i); t1Hd-]28V  
if(header!=null) J9/9
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); s]L`&fY]O  
Utility.log(header+" : "+con.getHeaderField(header)); ?U|~h1   
else Se"\PxBR  
break; IZJV6c
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} rM[Ps=5  
} *Ei~2O}  
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public void splitterStop() n9bX[+#d  
{ ji A$6dZU  
bStop = true; 3WPMS/  
} F`Q,pBl1p6  
b ";#qVv C  
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} "kP.Kx!  
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/* M*t@Q|$:  
**FileAccess.java E'XFn'  
*//文件访问(定位，写) 2(\>PN-  
package NetFox; T:;e73  
import java.io.*; htM5Nm[g  
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public class FileAccessI implements Serializable{ 7dPA>5"XD  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 =C`v+NPM)|  
RandomAccessFile oSavedFile; &[3y_,  
long nPos; ]d$)G4X1  
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public FileAccessI() throws IOException %3xH<$Gq5  
{ yc%AkhX*  
this("",0); gP/]05$e  
} IFG`  
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public FileAccessI(String sName,long nPos) throws IOException 7t@jj%F  
{ mXhr: e  
oSavedFile = new RandomAccessFile(sName,"rw"); d:A+s>`$M  
this.nPos = nPos; +"'h?7'C  
oSavedFile.seek(nPos); ,j&o H$mW  
} #7Qn\C2  
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/&kZ)XOi  
public synchronized int write(byte[] b,int nStart,int nLen) YnJ=&21  
{ ?_HTOOa  
int n = -1; !o*oT}6n  
try{ j:<E=[Kl  
oSavedFile.write(b,nStart,nLen); i]Kq  
n = nLen; [W^6=7EO  
} 1ed#nB%  
catch(IOException e) j1/J9F'  
{ F!fxA#  
e.printStackTrace (); HO' ELiZ_q  
} b?w4Nx#  
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return n; ge[\%  
} D;Az>]>q  
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} ^GRd;v=-@  
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/* X^aujK^@  
**SiteInfoBean.java QF%@MK0zC  
*/ &mY<e4  
package NetFox; _II;$_N  
f, ;sEV  
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public class SiteInfoBean { |W#^L`!G  
{?5EOp~  
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private String sSiteURL; //Site's URL T \0e8"iZ  
private String sFilePath; //Saved File's Path ENqJ9%sk7  
private String sFileName; //Saved File's Name f3yZx!K_Br  
private int nSplitter; //Count of Splited Downloading File yP-.8[;  
$]Fe9E?   
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public SiteInfoBean() ={zYcVI  
{//nSplitter的缺省值为5 -sc@S
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//default value of nSplitter is 5 hKX-]+6"  
this("","","",5); D}3E1`)W  
} Kx<bVK4"  
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hP9+|am%  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :UScbPG  
{ *B3` #t  
sSiteURL= sURL; JNMZn/  
sFilePath = sPath; 2OK%eVba  
sFileName = sName; @8/-^Rh*  
this.nSplitter = nSpiltter; 0|4XV{\qT$  
66z1_lA  
%PkJ7-/b|^  
} Rjh/M`|  
t%8*$"~X  
N'[^n,\(:  
public String getSSiteURL() `D?vmSQ  
{ ,&l>^w/  
return sSiteURL; }1(F~6RH  
} bNc=}^  
\&W~nYXq"  
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public void setSSiteURL(String value) S{ *RF)  
{ u1>|
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sSiteURL = value; \W*ouH  
} *4r;H2%c  
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V1"+4&R^T_  
public String getSFilePath() ux-Fvwoh  
{ &|gn%<^  
return sFilePath; T.&^1qWWA  
} r0S"}<8O  
0!!pNK%(  
!xa,[$w(^  
public void setSFilePath(String value) QEtZ]p1H@  
{ <4(rY9  
sFilePath = value; vw+ @'+  
} JY%c<  
c: #1Aym  
!&19%C4  
public String getSFileName() qY0GeE>N  
{ :Fm+X[n  
return sFileName; L!/USh:IP  
} v\f 41M7D  
 H\)on"  
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public void setSFileName(String value) WO_cT26Y  
{ PVV\@  
sFileName = value; >mh:OJH45  
} OGh bHa  
| F:?  
tS`fG;  
public int getNSplitter() xB 4A"|  
{ rXfQ_  
return nSplitter; ywCE2N<-V?  
} %:((S]vAi  
qb "H&)aHw  
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public void setNSplitter(int nCount) v#D9yttO{  
{ SAXjB;VH6  
nSplitter = nCount; f'R^MX2  
} ~@L$}Eu  
} P
Z
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[)9bR1wh  
1kTJMtZG~  
/* {w{|y[[d~  
**Utility.java v)J
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*/ UAH} ])U  
package NetFox; `@=}5 9+|  
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public class Utility { 1 !OQxY}f  
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public Utility() j3z&0sc2(0  
{ a<c %Xy/  
`^(6{p ?  
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} Fi(_A  
rN}{v}n  
//线程睡眠 RR^I*kRH  
public static void sleep(int nSecond) 0B1*N_.L@  
{ >iWl-hI-  
try{ <@5#  
Thread.sleep(nSecond); r~TiJ?8I  
} }=7tGqfw  
catch(Exception e) ){R_o
5  
{ ?$F:S%eH  
e.printStackTrace (); 0XL x@FYn  
} PS(9?rX#+  
} :uhvDYp(-  
In=3#u ,M  
//日志 ZXHG2@E)  
public static void log(String sMsg) I+8m1*  
{ QTK\"  
System.err.println(sMsg); >RE&>T^8  
} <k}>eGn  
D OPOzh  
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public static void log(int sMsg) <hQ@]2w$  
{ <}N0y*m  
System.err.println(sMsg); '-gk))u>)  
} "t`r_Aw  
} j08|zUe  
%|oY8;0|A>  
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/* 9= \bS6w*  
**TestMethod.java a5z.c_7r  
*/ m7^a4  
package NetFox; g|e^}voRM  
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:#
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public class TestMethod { 2%1g%  
:h*20iP  
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public TestMethod() 9j$ OU@N 8  
{ ///xx/weblogic60b2_win.exe H>;km$b +  
try{ 9v0.]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); / D#vs9S  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]n\WCU]0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Fov/?:f$  
fileFetch.start(); t*e+[  
} 1:q55!b  
catch(Exception e){e.printStackTrace ();} !z58,hv  
=EsKFt"  
"`C|;\w  
} 8Tv;,a  
76$19  
Rb\=\  
public static void main(String[] args) f+%J=Am  
{ $vlgiJ&f  
new TestMethod(); uSM4:!8  
} SECL(@0(^  
} {foF[M  
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