http断点续传简单实现（java)

/* |-vn,zpe  
**SiteFileFetch.java SBG.t:  
*/ Lq5Eu$;r  
package NetFox; zT _[pa)O`  
import java.io.*; 77zDHq=  
import java.net.*; )Yw m_f-N  
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public class SiteFileFetch extends Thread { 8$6^S{M3  
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SiteInfoBean siteInfoBean = null; //文件信息Bean EY.Z.gMZI(  
long[] nStartPos; //开始位置 P&8QKX3 j^  
long[] nEndPos; //结束位置 #,\qjY  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 c_.4~>qw  
long nFileLength; //文件长度 vsCy?  
boolean bFirst = true; //是否第一次取文件 &UoQ8&  
boolean bStop = false; //停止标志 L]Dl}z  
File tmpFile; //文件下载的临时信息 7T9Mo .  
DataOutputStream output; //输出到文件的输出流 9uA2M!~i2  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )?,X\/5  
public SiteFileFetch(SiteInfoBean bean) throws IOException WH0$v#8`v  
{ .^JsnP  
siteInfoBean = bean; *bTR0U  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `1U?^9Nf  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); rtgu{m02  
if(tmpFile.exists ()) CXhE+oS5z'  
{ 4qLH3I[Y  
bFirst = false; pksF|VS  
read_nPos(); )\Ay4d  
} c=\H&x3X  
else .VfBwTh7q8  
{ gye'_AR?k  
nStartPos = new long[bean.getNSplitter()]; \y0uGnmCj  
nEndPos = new long[bean.getNSplitter()]; ]tDuCZA  
} ?Y#x`DMh  
@m(ja@YC  
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} YA4;gH+  
*
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public void run() A@k`$xevVj  
{ aMycvYzH  
//获得文件长度 wT+b|K  
//分割文件 |c5r&oM&m  
//实例FileSplitterFetch dd@-9?6M  
//启动FileSplitterFetch线程 8X2
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//等待子线程返回 _^"0"<,  
try{ -H(\[{3{V  
if(bFirst) x$ oId{;  
{ d
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nFileLength = getFileSize(); 9Fv VM9  
if(nFileLength == -1) lDm0O)Dh!  
{ SLMnEtyTS  
System.err.println("File Length is not known!"); Z4'8x h)-  
} O&De!Gx  
else if(nFileLength == -2) @ wJ|vW_.  
{ j_2yTz"G-  
System.err.println("File is not access!"); 2n8spLZYGY  
} ley:=(  
else auV<=1<zJ  
{ pSlosv(6  
for(int i=0;i<nStartPos.length;i++) g4 G?hv`R  
{ C N
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); @u}1
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} h TY7`m">  
for(int i=0;i<nEndPos.length-1;i++) aR}L- -m  
{ 1'>wrGr  
nEndPos = nStartPos[i+1]; 
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} [N4#R  
nEndPos[nEndPos.length-1] = nFileLength; ^;]Q,*Q  
} vfZ.js/  
} )"Vd8*e  
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//启动子线程 Pn[R.u(l  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; lYt|C^  
for(int i=0;i<nStartPos.length;i++) <; (pol|  
{ AqHH^adzA:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), kX)Xo`^Ys  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), pAd 8-a  
nStartPos,nEndPos,i); &6
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M@b:~mI[sw  
fileSplitterFetch.start(); J$X
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} _9Zwg+oO[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +vh 4I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :_y}8am;H~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", bW9a_myE  
nEndPos = " + nFileLength); vw/L|b7G  
// fileSplitterFetch[nPos.length-1].start(); > R5<D'cEN  
:6r)HJ5sg  
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//等待子线程结束 AvS<b3EoN  
//int count = 0; #nOS7Q#uW  
//是否结束while循环 }pzUHl>  
boolean breakWhile = false; Fs,#d%4@%  
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while(!bStop) VS{po:]A  
{ +jPs0?}s  
write_nPos(); Z*Fxr;)d  
Utility.sleep(500); zJ2dPp~u  
breakWhile = true; sAG#M\A6  
9
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for(int i=0;i<nStartPos.length;i++) AQH\ ;L  
{ .0b$mSV[  
if(!fileSplitterFetch.bDownOver) dq&N;kk |  
{ d?uN6JH9  
breakWhile = false; 2MapB*  
break; n%J{Tcn6  
} !b0ANIp  
} ^+m6lsuA  
if(breakWhile) 1>BY:xZr  
break; -N3fhW#)  
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L93&.d@m9  
//count++; MvLmEmKb}\  
//if(count>4) 6pHn%yE*  
// siteStop(); ~RRp5x _  
} g]hTz)8fF  
Xj^Hy"HC^~  
'8$*gIQ8  
System.err.println("文件下载结束！"); Y%B:IeF}  
} W".: 1ov#B  
catch(Exception e){e.printStackTrace ();} [Pnk@jIk4  
} _4]GP3`  
?Thh7#7LM  
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//获得文件长度 TNHkHR[&  
public long getFileSize() #:yh2y7a%  
{ X?'v FC  
int nFileLength = -1; wInJ!1  
try{ MY[QYBkn}  
URL url = new URL(siteInfoBean.getSSiteURL()); ,'E+f%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Sl?@c/Ng  
httpConnection.setRequestProperty("User-Agent","NetFox"); m1mA:R\zM  
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7vRFF@eq}  
int responseCode=httpConnection.getResponseCode(); $Z!$E,@c  
if(responseCode>=400) {O4y Y=G  
{ g=T !fF=  
processErrorCode(responseCode); gW[(gf.oo  
return -2; //-2 represent access is error k{?Pgf27  
} aOj(=s  
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String sHeader; h*2NFL~#  
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for(int i=1;;i++) 3j]P\T  
{ }52]  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); a=m7pe^  
//Utility.log(in.readLine()); xTy[X"sJ  
sHeader=httpConnection.getHeaderFieldKey(i); yMQZulCWE  
if(sHeader!=null) xzqgem`[\  
{ U=<d
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if(sHeader.equals("Content-Length")) X~`<ik{q  
{ *Z+8L*k97  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); b xU13ESv  
break; PW[NW-S`c  
} Y0f"}A1  
} ?-y!FD}m&  
else Ax9a5;5WM  
break; ] X9
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} Fjc4[ C  
} Hkc
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catch(IOException e){e.printStackTrace ();} <K$X>&Ts  
catch(Exception e){e.printStackTrace ();} ?x*Ve2+]  
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Utility.log(nFileLength); b?p_mQKtZ  
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return nFileLength; V8aLPJ0_  
} eC9nOwp]xH  
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//保存下载信息（文件指针位置） M7\; Y  
private void write_nPos() 1nt VM+  
{ cVg!"  
try{ _*xjG \!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); tKnvNOhn  
output.writeInt(nStartPos.length); ,}("es\b  
for(int i=0;i<nStartPos.length;i++) (#dwIBBFt  
{ F|eKt/>e  
// output.writeLong(nPos); kiW|h)w_,v  
output.writeLong(fileSplitterFetch.nStartPos); ]/o0p  
output.writeLong(fileSplitterFetch.nEndPos); tP?pN]Q$,  
} t3~ZGOn  
output.close(); <`B4+:;w6  
} |Ew~3-u!  
catch(IOException e){e.printStackTrace ();} %[x oA)0!  
catch(Exception e){e.printStackTrace ();} d:U2b"k=/u  
} V!sT2  
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//读取保存的下载信息（文件指针位置） 9^;)~ G  
private void read_nPos() ^[7ZBmS  
{ ^x! N]  
try{ iK#5nY].  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q\P?[i]  
int nCount = input.readInt(); ^`W8>czi  
nStartPos = new long[nCount]; 5$v,%~$Xds  
nEndPos = new long[nCount]; '^TQ Ubw  
for(int i=0;i<nStartPos.length;i++) peA}/Jc  
{ OZ/P@`kN.f  
nStartPos = input.readLong(); Pl@3=s!~>~  
nEndPos = input.readLong(); :GXD-6}^|  
} \m>mE/N  
input.close(); QbF!V%+a's  
} h83;
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catch(IOException e){e.printStackTrace ();} 'u
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catch(Exception e){e.printStackTrace ();} Y7|R vLWoP  
} O#}'QZd'  
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private void processErrorCode(int nErrorCode) ileqI/40f  
{ .,)C^hs@  
System.err.println("Error Code : " + nErrorCode); .pP{;:Avpn  
} mSw$? >  
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//停止文件下载 }b//oe
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public void siteStop() M![aty@  
{ (QO8_  
bStop = true; X3z$f(lF%)  
for(int i=0;i<nStartPos.length;i++) 7O_@b$Q  
fileSplitterFetch.splitterStop(); qjK'sge/  
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} %R18  
} E3pnu.;U:_  
//负责部分文件的抓取 mfYY?]A*+  
**FileSplitterFetch.java (<= &#e?  
*/ .RI{\i`  
package NetFox; >)/,5VSE  
/rKdxsI*  

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import java.io.*; 9WXJz;  
import java.net.*; 5h"moh9tG  
: ryE`EhB  
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public class FileSplitterFetch extends Thread { iIOA54!o  
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String sURL; //File URL  aOS:rC  
long nStartPos; //File Snippet Start Position + _=&7  
long nEndPos; //File Snippet End Position a(+.rf;  
int nThreadID; //Thread's ID ?2Q9z-$  
boolean bDownOver = false; //Downing is over tBtG- X2  
boolean bStop = false; //Stop identical j@JhxCe1+R  
FileAccessI fileAccessI = null; //File Access interface uR|?5DK  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException y7K&@Y  
{ hAPWEh^  
this.sURL = sURL; 8\z5*IPGs  
this.nStartPos = nStart; K$S:V=y%r7  
this.nEndPos = nEnd; 4LO U[D  
nThreadID = id; 5t`:=@u  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 '6^20rj  
} *Q?
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public void run() N5 BC<pu  
{ K~j&Q{yws@  
while(nStartPos < nEndPos && !bStop) 5dH}cXs  
{ 0KW@j>=jK  
zJp}
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try{ QZcdfJck=+  
URL url = new URL(sURL); ]9xuLJ)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '@Zau\xC  
httpConnection.setRequestProperty("User-Agent","NetFox"); RUJkfi=$  
String sProperty = "bytes="+nStartPos+"-"; /Iwnl   
httpConnection.setRequestProperty("RANGE",sProperty); >900I4]I  
Utility.log(sProperty); Cu5fp.OS7  
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InputStream input = httpConnection.getInputStream(); w"s;R8  
//logResponseHead(httpConnection); Y{6vW-z_<  
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byte[] b = new byte[1024]; -WDU~VSU  
int nRead; ]7qn&(]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Uu~7+oaQ  
{ <h(KIY9T  
nStartPos += fileAccessI.write(b,0,nRead); ^/|agQ7D2  
//if(nThreadID == 1) P8tpbdZE-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OH`| c  
} %9,:  
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Utility.log("Thread " + nThreadID + " is over!"); 08J[9a0[  
bDownOver = true; #) e
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//nPos = fileAccessI.write (b,0,nRead); 8]@)0q {r  
} k lLhi<*  
catch(Exception e){e.printStackTrace ();} ` ZO#n  
} Z(fXN$  
} ^[K3]*!@  
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 U 6((  
//打印回应的头信息 k)Y}X)\36  
public void logResponseHead(HttpURLConnection con) t')47k\  
{ i$~2pr  
for(int i=1;;i++) N=1zhI:VaQ  
{ 'H"wu /#  
String header=con.getHeaderFieldKey(i); P5u Y1(  
if(header!=null) dGxk ql  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); r)ni;aP  
Utility.log(header+" : "+con.getHeaderField(header)); mR3)$!  
else l@ +lUx8  
break; %4F Q~  
} 8(yZX4OH>  
} hu?Q,[+o  
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public void splitterStop() +D[

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{ ~vqVASUc,  
bStop = true; 5a$Q}!6E.Y  
} X9W'.s.[Q  
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} \!!qzrq  
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/* L-B"P&  
**FileAccess.java $;kFuJF  
*//文件访问(定位，写) fkLI$Cl  
package NetFox; qOA+ao  
import java.io.*; K U 2LJ_~Y  
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public class FileAccessI implements Serializable{ ;E Z5/"T  
9YpgzCx Z  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 N$\'X<{  
RandomAccessFile oSavedFile; eWKFs)C]  
long nPos; 2nNBX2o&_  
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public FileAccessI() throws IOException o!R.QI^2VT  
{ ,g69?w  
this("",0); r[doN{%  
} 75@!j[QL<  
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public FileAccessI(String sName,long nPos) throws IOException ]><K8N3Z  
{ oRf.34  
oSavedFile = new RandomAccessFile(sName,"rw"); cyM9[X4rC  
this.nPos = nPos; zD#$]?@ b  
oSavedFile.seek(nPos); k|C~q
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} icO$9c  
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public synchronized int write(byte[] b,int nStart,int nLen) <x Q
vS^|[  
{ zKh^BwhO|X  
int n = -1; i-.]on
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try{ myq@X(K  
oSavedFile.write(b,nStart,nLen); s$%t*T2J>  
n = nLen; Ro}7ERA  
} ~]sj.>P  
catch(IOException e) +8<|P&fH  
{ )b%t4~7  
e.printStackTrace (); Lud[.>i  
} f ZEyXb  
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return n;  lu_kir~  
} 2 m"2>gX  
;mT|0&o>#  
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} Z\lJE>1  
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/* -_*ux!  
**SiteInfoBean.java 0W_olnZ  
*/ 2XX-  
package NetFox; ]\~s83?X  
(vR9vOpJ  
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public class SiteInfoBean { ZVelKI8>  
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private String sSiteURL; //Site's URL n-"(lWcp  
private String sFilePath; //Saved File's Path Arr(rM  
private String sFileName; //Saved File's Name ?|i C-7{8L  
private int nSplitter; //Count of Splited Downloading File qjBF]3%t%  
?l><?i  
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public SiteInfoBean() ?[Sac]h ys  
{//nSplitter的缺省值为5 0~a9gBG  
//default value of nSplitter is 5 1Yk!R9.  
this("","","",5); {6I)
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} r,43 gg  
0hNgr'  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /` ;rlH*  
{ ;L*Ku'6Mt  
sSiteURL= sURL; ]>9[}'u  
sFilePath = sPath; .4[\%r\i  
sFileName = sName; _J,lF-,  
this.nSplitter = nSpiltter; #\zC|%2+z  
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htuYctu`  
} :5'8MU
 
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public String getSSiteURL() .5^7Jwh  
{ 5i0vli/L  
return sSiteURL; ]/#3 P  
} yI{4h $c  
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public void setSSiteURL(String value) DqJzsk'd3  
{ ;hgRMkmz4<  
sSiteURL = value; c]/X >8;  
} B*@0
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public String getSFilePath() NiSybyR$  
{ _x`oab0@  
return sFilePath; 20,}T)}Tm  
} \H4$9lPk  
V;LV),R?  
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public void setSFilePath(String value) F"^/R  
{ f-BPT2U+  
sFilePath = value; T;M4NGmvd  
} TFZxk  
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public String getSFileName() :!QT ,  
{ 5M&<tj/[a0  
return sFileName; 6no&2a|D  
} iw{rns  
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public void setSFileName(String value) ~]Weyb[N  
{ ["H2H rI2  
sFileName = value; cK1 Fv6V#  
} 4n0Iw  I  
Krd0Gc~\|  
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public int getNSplitter() 5v[2R.eT-  
{ Tr.u'b(  
return nSplitter; mhgvN-? "h  
} WB.w3w[f  
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7
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public void setNSplitter(int nCount) TtWWq5X|  
{ $/kZKoF{f  
nSplitter = nCount; fyF8RTm{  
} xyrlR;Sk  
} "=Cjm`9~j  
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/* T0X+\&W  
**Utility.java O%1uBc  
*/ T(=Z0M  
package NetFox; EX/{W$ &K  
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public class Utility { 'j\~> a3\  
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public Utility() `hDH7u!U.  
{ #2dH2k\F  
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,: Ij@u>)  
} 6Zx)L|B  
97pfMk1_  
//线程睡眠 QT4&Ix,4T1  
public static void sleep(int nSecond) sdBB(  
{ 
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try{ 2f5YkmGc";  
Thread.sleep(nSecond); KjK-#F,@  
} iBk1QRdn  
catch(Exception e) #'5{ ?Cb  
{ ODxCD%L  
e.printStackTrace (); eyuQ}
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} 7 &iav2q  
} J
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1oI2  
//日志 Z4dl'v)9  
public static void log(String sMsg) pwVaSnre`  
{ 39bw,lRPV  
System.err.println(sMsg); @2~;)*  
} I&f!>y?,Z  
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PU-L,]K  
public static void log(int sMsg) '3=@UBs  
{ LaYd7Oyf]  
System.err.println(sMsg); d^Rea8  
} 9z+ZFIf7d  
} +t8#rT ^B  
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/* O jH"qi  
**TestMethod.java dN@C)5pm5`  
*/ UHS"{%  
package NetFox; K$wxiGg8P  
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@CS%=tE}U  
public class TestMethod { #kgLdd"  
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\s6VOR/  
public TestMethod() *-&+;|mM  
{ ///xx/weblogic60b2_win.exe ~!P&LZ  
try{ F{E`MK~f_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); j9R+;u/!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 24k;.o  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Bo;{ QoB  
fileFetch.start(); E-deXY  
} \F14]`i  
catch(Exception e){e.printStackTrace ();} -d[Gy- J  
825 QS`  
jd.w7.8  
} X2`n&JE  

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public static void main(String[] args) Ap> H-/C  
{ l6N"{iXU  
new TestMethod(); BD [<>Wm  
} s8;*Wt  
} A$rCo~E
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