http断点续传简单实现（java)

/* [z5pqd-  
**SiteFileFetch.java [z'PdYQR/{  
*/ wi|'pKG  
package NetFox; ]N!8U_U3  
import java.io.*; G0Eqo$W)S  
import java.net.*; W]}y:_t4
 
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public class SiteFileFetch extends Thread { \_bk+}WJ]s  
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SiteInfoBean siteInfoBean = null; //文件信息Bean vR[XbsNM  
long[] nStartPos; //开始位置 'avzESe~'  
long[] nEndPos; //结束位置 |:7O  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 IlJ!jq  
long nFileLength; //文件长度 nYhI0q  
boolean bFirst = true; //是否第一次取文件 W|XW2`3p  
boolean bStop = false; //停止标志 7O',X Y  
File tmpFile; //文件下载的临时信息 V^sZXdDNL  
DataOutputStream output; //输出到文件的输出流 e`27 ?  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） j*B,b4  
public SiteFileFetch(SiteInfoBean bean) throws IOException gY9HEfB  
{ &FHzd/  
siteInfoBean = bean;
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /@h)IuW  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `@!4#3H  
if(tmpFile.exists ()) I?<5 %  
{ GTgG0Ifeh  
bFirst = false; 8vpB(VxV+  
read_nPos(); JVy-Y  
} ~\B1\ G  
else I.As{0cc  
{ Tk\?$n  
nStartPos = new long[bean.getNSplitter()]; C^oj/}^  
nEndPos = new long[bean.getNSplitter()]; v50w}w'  
} BC.~wNz6  
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} uJhB>/Og  
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public void run() @#m@ .   
{ )nE=H,U?y  
//获得文件长度 vo<'7,  
//分割文件 ;:nx6wi  
//实例FileSplitterFetch T rK-XTev  
//启动FileSplitterFetch线程 wyWe2d  
//等待子线程返回 /&1FgSARK  
try{ moz*=a  
if(bFirst) !(2rU@.  
{ sa6/$  
nFileLength = getFileSize(); 4
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if(nFileLength == -1) 7-S?\:J  
{ b{4@~>i  
System.err.println("File Length is not known!"); %QYW0lE  
} 2E7vuFH4c  
else if(nFileLength == -2) gkkT<hEV=  
{ -|_#6-9  
System.err.println("File is not access!"); "]H_;:{f  
} xb8S)zO]Q  
else ]c/k%]o~  
{ 1j4tR#L  
for(int i=0;i<nStartPos.length;i++) ^phgNzD  
{ qrdA4S  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); my|]:(_0d  
} DD$YMM  
for(int i=0;i<nEndPos.length-1;i++) -(~OzRfYi  
{ %)'# d  
nEndPos = nStartPos[i+1]; dZMf5=tb  
} `hpX97v  
nEndPos[nEndPos.length-1] = nFileLength; <cig^B{nX  
} _TLB1T^/4  
} $>if@}u  
KNvvYwFH]  
Kd,8PV*_  
//启动子线程 K9G1>*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :[P)t %  
for(int i=0;i<nStartPos.length;i++) A?)nLp&Y  
{ WK$d<:"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), g+v
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siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), '\g-z  
nStartPos,nEndPos,i); OQ*BPmS-   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Yf&P|I
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fileSplitterFetch.start(); kz30! L  
} ' v)@K0P  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -/)>DOgUq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4{zz-4=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", kfc5ra>&  
nEndPos = " + nFileLength); v^A4%e<8^r  
// fileSplitterFetch[nPos.length-1].start(); Sao4MkSz[]  
(Mzv"FN]  
E!Ljq3iT`  
//等待子线程结束 @}{lp'8FYi  
//int count = 0; l4O&*,}l##  
//是否结束while循环  U=ek_FO  
boolean breakWhile = false; z.vERP56  
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while(!bStop) =(aA`:Nl  
{ qz_'v{uAj  
write_nPos(); _dQg5CmlG  
Utility.sleep(500); "O (N=|b  
breakWhile = true; ),!1B%  
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A.YXK%A%  
for(int i=0;i<nStartPos.length;i++) E&z`BPd  
{ /8Wfs5N  
if(!fileSplitterFetch.bDownOver) `W=3_  
{ 6<hE]B)  
breakWhile = false; 5 *R{N ~>  
break; 6,~Y(#  
} MrU0Jrk4+  
} VY1&YR}Y  
if(breakWhile) ,h<xL-  
break; :z-UnC||j  
#Ch*a.tI@  
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//count++; .D8|_B  
//if(count>4) [C-4*qOaa2  
// siteStop(); KHO@"+  
} q}xYme4  

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System.err.println("文件下载结束！"); QKB*N)%6  
} cfZ$V^xM  
catch(Exception e){e.printStackTrace ();} tEam6xNf,  
} ATG;*nIP  
93[&'  
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//获得文件长度 =:"wU  
public long getFileSize() gVscdg5  
{ h<0&|s*a)  
int nFileLength = -1; ZZ*+Tl\ s  
try{ eJ ;a}{ 4%  
URL url = new URL(siteInfoBean.getSSiteURL()); b0|;v-v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ASU.VY  
httpConnection.setRequestProperty("User-Agent","NetFox"); BB9+d"Sq  

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int responseCode=httpConnection.getResponseCode(); QW
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if(responseCode>=400) YZdV0-S  
{ (~IoRhp^  
processErrorCode(responseCode); ,L&d\M"f  
return -2; //-2 represent access is error $o%:ST4  
} CK=
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String sHeader; 'c/S$_r
 
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for(int i=1;;i++) Q8Fqf ;4  
{ <zWMTVaC  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); W/@-i|v  
//Utility.log(in.readLine()); T0e- X  
sHeader=httpConnection.getHeaderFieldKey(i); f`vu+nw  
if(sHeader!=null) sS{!z@\Lf  
{ M 8NWQ^Y  
if(sHeader.equals("Content-Length")) E' _6v  
{ `i5\(cdl  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =nff;Xu  
break; ss0`9:z  
} E (.~[-K4  
} `k.0d`3(  
else )&{<gyS1  
break; ,_M  
} HD_
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} : *8t,f~s^  
catch(IOException e){e.printStackTrace ();} Y/<`C  
catch(Exception e){e.printStackTrace ();} (Go1@;5I  
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8= "
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Utility.log(nFileLength); S Rb-eDk'  
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return nFileLength; "&%Lhyt  
} 7U1^=Y@t}  
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//保存下载信息（文件指针位置） *!r"+?0gN  
private void write_nPos() wx*03(|j;  
{ !O 0{ .k  
try{ V\nj7Gr:sF  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8pXqgIbmb  
output.writeInt(nStartPos.length); >&YUV.mLY  
for(int i=0;i<nStartPos.length;i++) %?X6TAtH  
{ mW=9WV  
// output.writeLong(nPos); Ws/\lD  
output.writeLong(fileSplitterFetch.nStartPos); {!&^VXZIT  
output.writeLong(fileSplitterFetch.nEndPos); !~Ptnr`;  
} z'01V8e  
output.close(); Y !%2vOt  
} :|%1i>O  
catch(IOException e){e.printStackTrace ();} 8J)Kn4jq  
catch(Exception e){e.printStackTrace ();} 7 -S?U~s  
} +z|@K=d#|  
e'A1%g)  
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//读取保存的下载信息（文件指针位置） ;_S DW  
private void read_nPos() yu}yON  
{ =p2: qSV  
try{ n
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,L=lg,lH^  
int nCount = input.readInt(); Yb\d(k$h  
nStartPos = new long[nCount]; :/R>0n,  
nEndPos = new long[nCount]; t{-*@8Ke  
for(int i=0;i<nStartPos.length;i++) : G'a
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{ l:+$Ks  
nStartPos = input.readLong(); <Rfx`mn  
nEndPos = input.readLong(); k&9[}a*  
} 0at['zw  
input.close(); Q9Vj8JO"{  
} 4Opf[3]  
catch(IOException e){e.printStackTrace ();} 4I8QM&7  
catch(Exception e){e.printStackTrace ();} /'a\$G"%6  
} 0TaN#  
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private void processErrorCode(int nErrorCode) b!<)x}-t>  
{ qVW3oj<2  
System.err.println("Error Code : " + nErrorCode); WK5B8u*<  
} lhX4MB"  
>dJ[1s]  
4_
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//停止文件下载 LP'~7FG  
public void siteStop() RiZ)#0  
{ 22/"
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bStop = true; c_T+T
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for(int i=0;i<nStartPos.length;i++) DQ@M?~1hp  
fileSplitterFetch.splitterStop(); EXsVZg"#  
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} &2nICAN[  
} L[^.pO  
//负责部分文件的抓取 sI6I5  
**FileSplitterFetch.java 7+;.Q  
*/ M8R/a[ -A  
package NetFox; i&q_h>ZTg  
8g {;o7  
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import java.io.*; z.|[g$F  
import java.net.*; Bbtc[@"X  
3^iVDbAW{  
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public class FileSplitterFetch extends Thread { @RZbo@{~  
~ike&k{  
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String sURL; //File URL hC4 M}(XM  
long nStartPos; //File Snippet Start Position `>GXJ~:D["  
long nEndPos; //File Snippet End Position JS/~6'uB  
int nThreadID; //Thread's ID ,Jx.Kj.,  
boolean bDownOver = false; //Downing is over Pk;1q?tGw  
boolean bStop = false; //Stop identical .X5A7 m  
FileAccessI fileAccessI = null; //File Access interface F:sUGM,  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {55f{5y3 c  
{ H<tU[U=G  
this.sURL = sURL;
"xNP"S  
this.nStartPos = nStart; KGGnypx`  
this.nEndPos = nEnd;
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nThreadID = id; 0p+36g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 kjDmwa+91T  
} Nza@6nI"  
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X|yVRQ?F`  
public void run() 2%|n}V[  
{ 4+89 M  
while(nStartPos < nEndPos && !bStop) *zMt/d*<&  
{ uPC(|U%  
}:Y)DH%u  
yMD3h$w3a  
try{ CM6! 1 7  
URL url = new URL(sURL); [{>3"XJ'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;U3K@_  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1p$*N  
String sProperty = "bytes="+nStartPos+"-"; /l+"aKW 2  
httpConnection.setRequestProperty("RANGE",sProperty); :2V|(:^'  
Utility.log(sProperty); 1,7 }ah_  
<rvM)EJv|  
hkRqtpYK  
InputStream input = httpConnection.getInputStream(); OdOn wY  
//logResponseHead(httpConnection); /([a%,DI  
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3.9/mztS  
byte[] b = new byte[1024]; m.<or?l'y>  
int nRead; j{johV+`8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) A]1dR\p  
{ BSy{"K*M  
nStartPos += fileAccessI.write(b,0,nRead); O0s,)8+z5D  
//if(nThreadID == 1) A%X=yqY  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h(^c5#.  
} F'"-aB ~  
S;u.Ds&  
49
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Utility.log("Thread " + nThreadID + " is over!"); 8Zy*#[-  
bDownOver = true; hgbf"J6V8  
//nPos = fileAccessI.write (b,0,nRead); _pzYmQ  
} Igw2n{})w  
catch(Exception e){e.printStackTrace ();} ^*+j7A.n  
} EPA 2_  
} mwMu1
#  
4`ZoAr-5|  
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//打印回应的头信息 %zo 6A1Q;  
public void logResponseHead(HttpURLConnection con) t1~k+  
{ ,tDLpnB@;  
for(int i=1;;i++) pMY7{z  
{ DliDBArxZ  
String header=con.getHeaderFieldKey(i); aHb&+/HZ  
if(header!=null) IwOL1\'T4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (N/-blto  
Utility.log(header+" : "+con.getHeaderField(header)); x iz+R9p  
else BS?i!Bm7  
break; 6pt|Crvu
 
} R+!oPWfb  
} m2/S(f  
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public void splitterStop() CEBu[TT/9  
{ ]1eZ<le`6  
bStop = true; hTWZIW@  
} 0!RP7Sx  
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"kC
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} &ld<fa(w+2  
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/* nf[KD,f  
**FileAccess.java gI9nxy  
*//文件访问(定位，写) 8k)*f+1o  
package NetFox; ,1cpV|mAr  
import java.io.*; s];0-65)  
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public class FileAccessI implements Serializable{ >rSCf=  
C1(RgY|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 bxO[y<|XL  
RandomAccessFile oSavedFile; :'xZF2  
long nPos; {<a)+S.6U  
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public FileAccessI() throws IOException )2q r^)  
{ 4F6I7lu  
this("",0); P: L6Zo-J  
} ,7Ejb++/M,  
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public FileAccessI(String sName,long nPos) throws IOException W$Xr:RU  
{ X\w["!B  
oSavedFile = new RandomAccessFile(sName,"rw"); cvf?ID84  
this.nPos = nPos; j?T>S]xOX  
oSavedFile.seek(nPos); BHS@whj  
} vl6|i)D  
}}u`*&,g  
&;WK=#  
public synchronized int write(byte[] b,int nStart,int nLen) lxbC 7?O
 
{ M+^ NF\  
int n = -1; 8zcSh/
 
try{ ^CM@VmPp  
oSavedFile.write(b,nStart,nLen); M,yxPHlN  
n = nLen; I,05'edCQ  
} +uj;00 D  
catch(IOException e) IP-M)_I
  
{ NPFI^Uj#A  
e.printStackTrace (); U3-MvI,Q  
} 9i lJ  
8e ?9:VM]  
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return n; f}KV4'n  
} !KT.p2\  
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} W5e>Z&&  
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/* Oiqc]4TL  
**SiteInfoBean.java xRO9o3  
*/ Snn4RB<(  
package NetFox; 3u 7A(  
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public class SiteInfoBean { W5()A,R  
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private String sSiteURL; //Site's URL )7-mALyW  
private String sFilePath; //Saved File's Path WP Gp(Xw  
private String sFileName; //Saved File's Name E7.{SGH}  
private int nSplitter; //Count of Splited Downloading File wr(*RI"  
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public SiteInfoBean() Fi7~JZZ  
{//nSplitter的缺省值为5 *lu*h&Y  
//default value of nSplitter is 5 O*N:.|dUw  
this("","","",5); 1W-kZ(e  
} Lpnw(r9Y  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) s<:);-tL  
{ &oJ[ *pQ  
sSiteURL= sURL; a@9W'/?igk  
sFilePath = sPath; x
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sFileName = sName; Xk:3w
,  
this.nSplitter = nSpiltter; q$s)(D  
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} /xr75|-8  
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public String getSSiteURL() .
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{ ZEpu5`  
return sSiteURL; >* F#ZZv}p  
} \l# H#~  
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public void setSSiteURL(String value) -]YsiE?r  
{ Nr"GxezU+A  
sSiteURL = value; _j{)%%?r  
} 1Mx2%  
Y(ClG*6 ++  
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public String getSFilePath() ADP3Nic  
{ qC=ZH#  
return sFilePath; z,@R jaX  
} VG$%Vs  
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public void setSFilePath(String value) :9q|
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{ AT2D+Hi=E  
sFilePath = value; xa !/.  
} 1-<?EOYaE  
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jd"YaZOQ  
public String getSFileName() >>;He7  
{ >m=
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return sFileName; JuRWR0@`  
} An,TunX  
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,w
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public void setSFileName(String value) =BV_?  
{ s%m?Yh3  
sFileName = value; M?n}{0E4  
} mM+^v[=  
.\)e

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public int getNSplitter() B
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{ {n<1uh9~$8  
return nSplitter; UD5
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} |h((SreO  
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public void setNSplitter(int nCount) a+9
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{ X&@>M}  
nSplitter = nCount; wLg@BSC.  
} Y]B9*^d<  
} uhwCC  
/CbM-jf  
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/* z}*L*Sk  
**Utility.java bZ+Hu~  
*/ =}e{U&CX  
package NetFox; ws,VO*4  
/de~+I5AB~  
hs
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public class Utility { 6HpiG`  
:D !/.0  
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public Utility() FuFICF7+C  
{ Rp}Sm,w(  
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} COH>B1W@  
|4` ;G(ta  
//线程睡眠 =feVT2*  
public static void sleep(int nSecond) ,pdf$) XB  
{ RNcnE1=  
try{ f4|ir3oy  
Thread.sleep(nSecond); }|c-i.0=
 
} HLq2avs\  
catch(Exception e) F/df!I~  
{ P4s,N|bs`  
e.printStackTrace (); %6:"
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} 8ROZ]Xh,x  
} th{Ib@o  
r#6djs1  
//日志 #!4 HSBf  
public static void log(String sMsg) I5rAL\y-G  
{ -8t&&fIA  
System.err.println(sMsg); SMA' VU  
} U{9yfy  
88DMD"$B  
gy5R"_MU  
public static void log(int sMsg) &Z7NF|  
{ buMST&  
System.err.println(sMsg); bp P3#~ K  
} -{$L`{|G  
} ,mt=)Ac  
9t&m\J >8;  
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/*  ;W@  
**TestMethod.java g'.(te |  
*/ -&np/tEu&  
package NetFox; ;7m
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public class TestMethod { h)X"<a++N  
X`k#/~+0  
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public TestMethod() qu/b:P  
{ ///xx/weblogic60b2_win.exe 8fb<hq<  
try{ a0&R! E;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); b5^-qc6X  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;k,#o!>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); IvB)d}p  
fileFetch.start(); 
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} A_|X54}w&  
catch(Exception e){e.printStackTrace ();} 7KV0g1GQ  
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6"GHVFB  
} bN>|4hS  
?T8^tGD[  
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public static void main(String[] args) V<t!gT#&o!  
{ SD1M`PI  
new TestMethod(); jg(cpo d  
} +J2;6t  
} #AH<dS  
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