http断点续传简单实现（java)

/* MJ7Y#<u  
**SiteFileFetch.java (2$( ?-M  
*/ EzDk}uKY0R  
package NetFox; r9X?PA0f  
import java.io.*; Ae mDJ8Y  
import java.net.*; JQ}$Aqk  
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public class SiteFileFetch extends Thread { Z= jr-)kK  
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SiteInfoBean siteInfoBean = null; //文件信息Bean q/4YS0CqE  
long[] nStartPos; //开始位置 I*LknU@  
long[] nEndPos; //结束位置 Rz(QC\(  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -9"['-WH,  
long nFileLength; //文件长度 'I_Qb$  
boolean bFirst = true; //是否第一次取文件 eL^.,H0  
boolean bStop = false; //停止标志 NxjB/N  
File tmpFile; //文件下载的临时信息 Lk~ho?^`  
DataOutputStream output; //输出到文件的输出流 OTC!wI g  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） kspTp>~  
public SiteFileFetch(SiteInfoBean bean) throws IOException !g Z67  
{ thV>j9'  
siteInfoBean = bean; RMX:9aQ3F  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Sczc5FG  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); UQ'\7OS  
if(tmpFile.exists ()) #~SP)Ukp  
{ 8dV=[+  
bFirst = false; /<E5"Mm%  
read_nPos(); Ge,;8N88  
} Xua+cVc\y  
else lCAIK  
{ QF{4/y^j{  
nStartPos = new long[bean.getNSplitter()]; %{YN
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nEndPos = new long[bean.getNSplitter()]; ;w'D4p= P  
} [`p=(/I&L  
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} M(jgd  
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public void run() i7ISX>%  
{ kjEEuEv  
//获得文件长度 5nv<^>[J  
//分割文件 |_o=^?z'  
//实例FileSplitterFetch R>,:A%?^b5  
//启动FileSplitterFetch线程 &n6$rBr%  
//等待子线程返回 i-bJS6  
try{ wB.Nn/p  
if(bFirst) 1c<=A!"{  
{ ZX5xF<os8  
nFileLength = getFileSize(); cs T2B[f9D  
if(nFileLength == -1) /GIxR6i  
{ ^\\Tx*#i  
System.err.println("File Length is not known!"); GKvN* SU=  
} @kk4]:,w  
else if(nFileLength == -2) ojQI7 Uhw  
{ H,+I2tEs  
System.err.println("File is not access!"); Mu2  
} Sl-v W  
else G"X8}:}  
{ #[zI5)Meh  
for(int i=0;i<nStartPos.length;i++) t'BLVCu  
{ (7XCA,KTGI  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); W5?yy>S6N  
} Vy*:ne  
for(int i=0;i<nEndPos.length-1;i++) Xv<B1  
{ a["2VY6Eq@  
nEndPos = nStartPos[i+1]; &krwf ]|  
} 0@G")L Ue0  
nEndPos[nEndPos.length-1] = nFileLength; b7
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} r`AuvwHPs[  
} GDu~d<RH  
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//启动子线程 *.\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; vz^<YZMu  
for(int i=0;i<nStartPos.length;i++) q-]`CW]n  
{ *H?!;u=8  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Gp4A.\7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), N5]0/,I
}  
nStartPos,nEndPos,i); }b=}uiR#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :T]o)  
fileSplitterFetch.start(); xEf'Bmebk  
} VYt!U
  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9Xl`pEhC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); y]J89  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", WcHgBbNe  
nEndPos = " + nFileLength); 0{dz5gUde  
// fileSplitterFetch[nPos.length-1].start(); #ggf' QIHp  
N@O8\oQG  
p"l3e9&'j  
//等待子线程结束 w"SoeU  
//int count = 0; YyTSyP4  
//是否结束while循环 9uRFnzJVx  
boolean breakWhile = false; BT)X8>ct  
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while(!bStop) \[gReaI  
{ slg ]#Dy  
write_nPos(); HPb]Zj  
Utility.sleep(500); Q3|T':l4  
breakWhile = true; GP&vLt51  
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for(int i=0;i<nStartPos.length;i++) Pcu#lWC$  
{ $aN-Y?U%  
if(!fileSplitterFetch.bDownOver) N@Y ljz|  
{ TF 
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breakWhile = false; <$F\Nk|x  
break; yY[<0|o u  
} fv`O4  
} taFn![}/!g  
if(breakWhile) 87:!C5e}  
break; 5B&;uY   
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//count++; v^zu:Z*  
//if(count>4) oP!;\a( SL  
// siteStop(); bYi`R)  
} 2RN)<\P  
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System.err.println("文件下载结束！"); :6zG7qES3  
} %{/%mJoX  
catch(Exception e){e.printStackTrace ();}
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}
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qf=1?=l291  
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//获得文件长度 ,
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public long getFileSize() Ma8_:7`>O  
{ rg{9UV
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int nFileLength = -1; {dL?rQ>5L  
try{ 94 e): jS  
URL url = new URL(siteInfoBean.getSSiteURL()); ;x:rZV/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %H]lGN)  
httpConnection.setRequestProperty("User-Agent","NetFox"); X=Ys<TM,  
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p=C%Hmd5E  
int responseCode=httpConnection.getResponseCode(); m;D- u>o  
if(responseCode>=400) wKi^C8Z2  
{ 
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processErrorCode(responseCode); mwY IJy[  
return -2; //-2 represent access is error d3W0-INL  
} K]j0_~3
s  
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String sHeader; )ZBY* lk9  
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for(int i=1;;i++) ^=:9)CNw(  
{ *;m5'}jsy  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); x5QaM.+=J  
//Utility.log(in.readLine()); '0\@McU]  
sHeader=httpConnection.getHeaderFieldKey(i); t=u Qb=  
if(sHeader!=null) 4'6`Ll|iq  
{ o99pHW(E  
if(sHeader.equals("Content-Length")) ^)?d6nI  
{ >0dv+8Mn  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); M/q E2L[y  
break; CBDG./  
} m8SA6Y\  
} $&"V^@  
else C=s1R;"H  
break; !A>z(eIsv`  
} ?UK|>9y}Z  
} 7C$ 5  
catch(IOException e){e.printStackTrace ();} cZ(elZ0~  
catch(Exception e){e.printStackTrace ();} 0b/WpP  
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Utility.log(nFileLength); t\RF=BbJJ  
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return nFileLength; H)aQ3T4N5  
} etoo #h"]1  
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//保存下载信息（文件指针位置） @JvPx0  
private void write_nPos() @h*fFiY&{  
{ gqR)IVk>%  
try{ >@YtDl8R  
output = new DataOutputStream(new FileOutputStream(tmpFile)); WWL4`s  
output.writeInt(nStartPos.length); UjOB98Du  
for(int i=0;i<nStartPos.length;i++) }?&k a$rI  
{ e#,~,W.H  
// output.writeLong(nPos); ]$p{I)d&  
output.writeLong(fileSplitterFetch.nStartPos); P
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output.writeLong(fileSplitterFetch.nEndPos); OiAJ[L  
} ?-tVSRKQ  
output.close(); ?KITC;\\  
} R(-<BtM!-  
catch(IOException e){e.printStackTrace ();} }BiiE%a  
catch(Exception e){e.printStackTrace ();} $2<d<Um~z  
} ^/5XZ} *  
#/NS&_Ge0s  
,
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//读取保存的下载信息（文件指针位置） <BO)E(  
private void read_nPos() ? tfT8$
  
{
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try{ 7HVZZ!>~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); kGL1!=>  
int nCount = input.readInt(); l^d[EL+  
nStartPos = new long[nCount]; 7@6g<"I  
nEndPos = new long[nCount]; 'kYwz;gp  
for(int i=0;i<nStartPos.length;i++) .i^7|o:  
{ (mtoA#X1:h  
nStartPos = input.readLong(); s;1]tD  
nEndPos = input.readLong(); S,U Pl}KF  
} `fNG$ODL   
input.close(); t6BHGX{o  
} Hg9CZMko  
catch(IOException e){e.printStackTrace ();} _BFOc>0  
catch(Exception e){e.printStackTrace ();} Dw7vv]+ S  
} lc_E!"1  
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private void processErrorCode(int nErrorCode) /t6X(*xoy  
{ {QbvR*gv  
System.err.println("Error Code : " + nErrorCode); 4CQ"8k(S"  
} AW#<i_Ybf  
Z4){ 7|~a  
x!_<z''  
//停止文件下载 4lqH8l.  
public void siteStop()  6l$L~>  
{ QZX~T|Ckv  
bStop = true; 
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for(int i=0;i<nStartPos.length;i++) Cda!
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fileSplitterFetch.splitterStop(); \uME+NF  
+[J/Zw0{  
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} BYY RoE[P  
} :L_BG)dM  
//负责部分文件的抓取 aF|d^  
**FileSplitterFetch.java `z0{S!  
*/ XE3'`D!  
package NetFox; ,Rx{yf]k  
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import java.io.*; V:/7f*n7  
import java.net.*; _SACqamo5s  
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public class FileSplitterFetch extends Thread { ubu?S%`  
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String sURL; //File URL W23]Bx  
long nStartPos; //File Snippet Start Position BZb]SoA
L  
long nEndPos; //File Snippet End Position n,~;x@=5  
int nThreadID; //Thread's ID f'q 28lVf  
boolean bDownOver = false; //Downing is over [+w3J#K  
boolean bStop = false; //Stop identical [ BT)l]  
FileAccessI fileAccessI = null; //File Access interface PY3ps2^K.  
{B*W\[ns  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]O{u tm  
{ .Hc(y7HV  
this.sURL = sURL; okq[ o90  
this.nStartPos = nStart; N~pIC2Woo  
this.nEndPos = nEnd; r}u%#G+K,  
nThreadID = id; I _i6-<c.Q  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 MHL("v(@B  
} pPVRsXy  
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public void run() +Z!;P Z6  
{ =2y8CgLj  
while(nStartPos < nEndPos && !bStop) _ nP;Fx  
{ #'OaKt?Z)  
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try{ w62=06`@  
URL url = new URL(sURL); 2X-l{n;>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fqs]<qi  
httpConnection.setRequestProperty("User-Agent","NetFox"); 91of~ffh  
String sProperty = "bytes="+nStartPos+"-"; ==/n(LBD  
httpConnection.setRequestProperty("RANGE",sProperty); ha;l(U>  
Utility.log(sProperty); "Lh  
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InputStream input = httpConnection.getInputStream(); BpO9As 1um  
//logResponseHead(httpConnection); ZyR_6n>L$  
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6AN)vs}  
byte[] b = new byte[1024]; yBLUNIr  
int nRead; R7~Yw*#,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) V 'X;jC  
{ :L0/V~D  
nStartPos += fileAccessI.write(b,0,nRead); Lc<eRVNd,  
//if(nThreadID == 1) %lr|xX  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -{|`H[nmD  
} %;z((3F  
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Utility.log("Thread " + nThreadID + " is over!"); #$\fh;!W  
bDownOver = true; Y{f7 f'_  
//nPos = fileAccessI.write (b,0,nRead); '#O_}|ZN  
} kE;O7sN   
catch(Exception e){e.printStackTrace ();} ID1?PM  
} !c<wSQ,  
} =He.fEy  
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LT+3q%W.UC  
//打印回应的头信息 'ul\Q`N3  
public void logResponseHead(HttpURLConnection con)
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{ Qq0l*)mX  
for(int i=1;;i++) b'x$2K;E  
{ |'HLz=5\  
String header=con.getHeaderFieldKey(i);
AB.(CS=i  
if(header!=null) .g\6g~n  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); TTI81:fku  
Utility.log(header+" : "+con.getHeaderField(header)); =OTm2:j#yQ  
else XeUC0K[D  
break; daZQz"PP  
} )_jSG5k  
} =Pe><k  
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public void splitterStop() w#G2-?aj  
{ V7=SV:+1or  
bStop = true; kpfwqHT  
} "oc$  
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} 0vs0*;F;  
(7$$;  
}dSFAKI2dM  
/* j!#OG  
**FileAccess.java 7CvD'QW /  
*//文件访问(定位，写) UWG+#,1J.\  
package NetFox; Kf7WcJ4b  
import java.io.*; =N.!k Vkl  
!ZtSbOC'  
;Fl<v@9  
public class FileAccessI implements Serializable{ cep$_Ja  
~waNPjPRG  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 M<8ML!N0;t  
RandomAccessFile oSavedFile; Ef7:y|?  
long nPos; `U`#I,Ln[  
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public FileAccessI() throws IOException whc[@Tyx  
{ ysXx%k  
this("",0); B0mLI%B  
} gb-{2p>}  
-
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public FileAccessI(String sName,long nPos) throws IOException M^SuV  
{ 2M6dMvS  
oSavedFile = new RandomAccessFile(sName,"rw"); sy<iKCM\  
this.nPos = nPos; ahIE;Y\j'  
oSavedFile.seek(nPos); mVH,HqsXa  
} H:oQ  
SX+RBVZU  
#n})X,ip2  
public synchronized int write(byte[] b,int nStart,int nLen) Sgj/s~j~1  
{ )r!e2zc=Q  
int n = -1; V7<eQ0;m  
try{ Px4/O~bLk  
oSavedFile.write(b,nStart,nLen); oNRG25  
n = nLen; z-u?s`k**  
} v|+5:jFOqb  
catch(IOException e) z:G}>fk5  
{ sk X]8  
e.printStackTrace (); BnEdv8\,&s  
} m/${8  
6}&^=^-  
f~\Xg7<  
return n; 6M><(1fT  
} $-G`&oT  
Lar r}o=  
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} fD6GQ*  
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/* c4]u&tvjJ  
**SiteInfoBean.java pieT'mA  
*/ E <@\>y.[  
package NetFox; .hz2&9Ow  
!Cb=B  
j@P5(3r  
public class SiteInfoBean { Di.;<v#FL  
o~~9!\  
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private String sSiteURL; //Site's URL
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private String sFilePath; //Saved File's Path t.=Oj  
private String sFileName; //Saved File's Name 5+L8\V9;  
private int nSplitter; //Count of Splited Downloading File :('I)C  
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public SiteInfoBean() s-6:N9-  
{//nSplitter的缺省值为5 V*qY"[  
//default value of nSplitter is 5 {8m1dEC^@Q  
this("","","",5); _Y#Bm/*  
} {%7<"  
~I$}#  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8-A|C< "  
{ SfDQ;1?  
sSiteURL= sURL; #O|lfl>}  
sFilePath = sPath; 8
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sFileName = sName; TG]}X\c+V|  
this.nSplitter = nSpiltter; nEVbfNo0  
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#: hVF/  
} &7][@v  
/co%:}ln  
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public String getSSiteURL() BTs0o&}e  
{ "_)|8|gN  
return sSiteURL; #JS`e_3Rr  
} b`]M|C [5  
*<dHq
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u+DX$#-n!]  
public void setSSiteURL(String value) j |td,82.  
{ 5B|,S1b  
sSiteURL = value; 2FT-}w0;  
} AfE%a-;:  
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public String getSFilePath() n_;S2KM  
{ 'z](xG<  
return sFilePath; DPeVKyjU  
} {rfte'4;=  
Y
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?Ccw4]YO,=  
public void setSFilePath(String value) bX&e_Pd  
{ T/Q==Q{W:  
sFilePath = value; "G kI5!  
} w`Xg%*]}  
||fvKyKW>  
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public String getSFileName() q\_DJ)qpn  
{ <i7agEdZD  
return sFileName; qZ?{-Vw  
} TK %<a/  
%^U"S
pv;  
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public void setSFileName(String value) EqQ3=XMUL@  
{ 3.~h6r5-  
sFileName = value; 9 P~d:'Ib  
} xH@'H?  
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#{~7G%GPY5  
public int getNSplitter() |Cq8%  
{ DUo0w f#D^  
return nSplitter; N*':U^/t4J  
} wO!% q[  
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d/4ubf+$k  
public void setNSplitter(int nCount) Ff&R0v  
{ F7V6-V{_  
nSplitter = nCount; 8.-S$^hj~6  
} nHVPMi>  
} j`hNZ%a  
? KF=W  
;,v.(Z ic  
/* ^f6 {0  
**Utility.java H.9yT\f.  
*/ -O /T?H  
package NetFox; "Whwc   
~R$[n.Vpk  
XK3!V|y`  
public class Utility {
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IR  
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+/(|?7i@  
public Utility() A{M+vsL  
{ IuDT=A  
&p)@8HY  
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} IY03"  
j7,13,t1-  
//线程睡眠 eL_^: -   
public static void sleep(int nSecond) U(P:Je  
{ Z$1.^H.Db  
try{ )ph30B  
Thread.sleep(nSecond); C~{xL>I  
} 7^&lbzVbm(  
catch(Exception e) R~!\-6%_  
{ / Z1Wy-Z  
e.printStackTrace (); '%);%y@v  
} dA|Lufy#  
} !2#\| NJk  
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//日志 4p?+LdL  
public static void log(String sMsg) ,T/GW,?  
{ &+,:u*%  
System.err.println(sMsg); P:>'   
} iF8@9m  
#gF2(iK6  
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public static void log(int sMsg) Imke/ =h  
{ k"5`:qL  
System.err.println(sMsg); \ hrBq^I  
} I7A7X*  
} Kq8(d`g}  
sC!1B6:  
>,kL p|gA  
/* 4v0dd p  
**TestMethod.java KUlB2Fqi  
*/ Ko4)0&  
package NetFox; {qY3L8b  
`S5>0r5[  
g%+ql[(4  
public class TestMethod { ,eyp$^2  
V/@[%w=  
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public TestMethod() >).@Nb;e  
{ ///xx/weblogic60b2_win.exe $^] 9  
try{ VtD@&N  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); D7EXqo  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); (_s;aK  
SiteFileFetch fileFetch = new SiteFileFetch(bean); o*?[_{xW  
fileFetch.start(); }Q,(u  
} rf)PAdj|~  
catch(Exception e){e.printStackTrace ();} BN_!Y)Fl  
9qnuR'BDu  
A>4l/  
} +GRxHuW,  
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public static void main(String[] args) UIO6|*ka  
{ ^xzE^"G6  
new TestMethod(); an-\k*w  
} [t {vYo  
} d]^\
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