http断点续传简单实现（java)

/* 42Z:J 0  
**SiteFileFetch.java jBLTEb  
*/ 22l'kvo4"  
package NetFox; !dqC6a  
import java.io.*; Kr
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import java.net.*; BIx*t9wA  
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public class SiteFileFetch extends Thread { m eF7[>!U  
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SiteInfoBean siteInfoBean = null; //文件信息Bean k6tCfq;  
long[] nStartPos; //开始位置 =M\yh,s!  
long[] nEndPos; //结束位置 bxXpw&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 GkAd"<B  
long nFileLength; //文件长度 0Wr<l%M)+  
boolean bFirst = true; //是否第一次取文件 14,)JZN  
boolean bStop = false; //停止标志 UTA|Ps$  
File tmpFile; //文件下载的临时信息 k[Em~>m  
DataOutputStream output; //输出到文件的输出流 uyj!$}4  
'@n"'vks(\  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） &h5Vhzq(<  
public SiteFileFetch(SiteInfoBean bean) throws IOException 6{2y$'m8  
{ x ytrd.  
siteInfoBean = bean; FnGKt\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); b_x!m{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1iT_mtXK$  
if(tmpFile.exists ()) TegdB|y7O  
{ j*%#~UFw  
bFirst = false; R`j"iC2  
read_nPos(); Pf;OYWST  
} nW=6nCyvo  
else x;mw?B[  
{ 9{pT)(Wnb  
nStartPos = new long[bean.getNSplitter()]; z g7Q`  
nEndPos = new long[bean.getNSplitter()]; YD4I2'E  
} $Itmm/M  
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} }e7Rpgu  
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public void run() Y>$5j}K  
{ *l7 `
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//获得文件长度 P]+B}))  
//分割文件 `,O7
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//实例FileSplitterFetch {z oGwB  
//启动FileSplitterFetch线程 %Wtf24'o;v  
//等待子线程返回 =ejcP&-V/  
try{ F8%^Ed~@  
if(bFirst) xF_u:}7`  
{ I
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nFileLength = getFileSize(); O"\4[HE^  
if(nFileLength == -1) ?q!4REM  
{ \`k=
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System.err.println("File Length is not known!"); qnP4wRpr  
} $QiMA,  
else if(nFileLength == -2) p{E(RsA  
{ eF3NyL(A  
System.err.println("File is not access!"); ?V`-z#y7  
} 3W'fEh5  
else ;MfqI/B{  
{ Y{dSQ|xz^  
for(int i=0;i<nStartPos.length;i++) uQdeKp4(  
{ f1NHW|_j  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); e1[ReZW  
} -Mo4`bN  
for(int i=0;i<nEndPos.length-1;i++) |q4=*Xq  
{ dv. 77q  
nEndPos = nStartPos[i+1]; TOiLv.Dor  
} qO@vXuul,  
nEndPos[nEndPos.length-1] = nFileLength; u6C_*i{2  
} fw%p_Cm  
} fRNj *bIV  
BB}WfA  
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//启动子线程 ivo3pibk%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2I:P}!  
for(int i=0;i<nStartPos.length;i++) sI\NX$M  
{ 6jpzyf=~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +[}y` -t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @<K<"`~H  
nStartPos,nEndPos,i); yz [pF  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aG1Fj[,  
fileSplitterFetch.start(); q}i#XQU  
} T4x%3-4;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .XgY&5Qk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); wPU5L*/*i  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Y
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nEndPos = " + nFileLength); $mxG-'x%K  
// fileSplitterFetch[nPos.length-1].start(); :{<|,3oNdR  
WvU[9ME^)  
X -1r$.
  
//等待子线程结束 LR&MhG7  
//int count = 0; 2IJniS=[>  
//是否结束while循环 Xau%v5r  
boolean breakWhile = false; o?]Q&,tO  
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while(!bStop) 9>{ml&$  
{ wQW`Er3w  
write_nPos(); .i\FK@2  
Utility.sleep(500); ;)ay uS sQ  
breakWhile = true; H[w';u[%  
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for(int i=0;i<nStartPos.length;i++) '&Ur(axs  
{ (bm> )U=  
if(!fileSplitterFetch.bDownOver) Dp['U
  
{ /'oo;e  
breakWhile = false; 9ad`q+kY  
break; xkf2;  
} f)vnm*&-  
} xS,F DPA  
if(breakWhile) B\D)21Ik}%  
break; XK~HfA?  
USART}Us4  
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//count++; /%&5Iq\:vA  
//if(count>4) G{?`4=K  
// siteStop(); 0%xb):Ctw  
} ")ys!V9  
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System.err.println("文件下载结束！"); bV:<%l]  
} Jd `Qa+  
catch(Exception e){e.printStackTrace ();} RH,x);
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} -[!t=qi  
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9qa/f[G  
//获得文件长度 &y0GdzfQd  
public long getFileSize() a2?@OJ  
{ ['>ZC3?"h  
int nFileLength = -1; !0pK8k&MG  
try{ Bor_(eL^
 
URL url = new URL(siteInfoBean.getSSiteURL()); RaLV@>jPm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z<<=2Xl(  
httpConnection.setRequestProperty("User-Agent","NetFox"); uPho|hDp  
it{Jd\/hR  
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int responseCode=httpConnection.getResponseCode(); ftmPdha%+  
if(responseCode>=400) nh7_ jEX  
{ UvMkL  
processErrorCode(responseCode); _zbIS&4  
return -2; //-2 represent access is error /IcGJ&;  
} Q~.t8g/  
~(*tcs]hY  
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String sHeader; '<,Dz=
 
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XD8Cf!  
for(int i=1;;i++) Qu<6X@+5  
{ |L*=\%t8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $+2QbEk&-  
//Utility.log(in.readLine()); >/RFff]Fh0  
sHeader=httpConnection.getHeaderFieldKey(i); E el*P M  
if(sHeader!=null) ZweAY.]e  
{ Ij
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if(sHeader.equals("Content-Length"))  &I-T  
{ kE6/
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); RU#}!Kq  
break; &b>&XMIK  
} Slo^tqbG  
} )AEtW[~D  
else bGB$a0  
break; 3ouy-SQ  
} k)z>9z%D  
} ;jx[ +  
catch(IOException e){e.printStackTrace ();} )Vy0V=  
catch(Exception e){e.printStackTrace ();} ,_$J-F
?  
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Utility.log(nFileLength); ?zP 2   
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return nFileLength; vaQsG6q[  
} yX*$PNL5w  
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}; 7I   
//保存下载信息（文件指针位置） mc`Z;D/mt  
private void write_nPos() '+l"zK]L-  
{ L1+s0g>  
try{ k$5l kP.  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q)XH5C2X  
output.writeInt(nStartPos.length); cjhwJ"`H  
for(int i=0;i<nStartPos.length;i++) k:V9_EI=  
{ hl0X,G+@  
// output.writeLong(nPos); X'\h^\yOo  
output.writeLong(fileSplitterFetch.nStartPos); R<I#. KD  
output.writeLong(fileSplitterFetch.nEndPos); z.(DDj  
} lq.]@zlSO  
output.close(); G2y1S/  
} rS!@AgPLE  
catch(IOException e){e.printStackTrace ();} *MlEfmB(  
catch(Exception e){e.printStackTrace ();} /? d)01  
} pdFO!A_t  
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//读取保存的下载信息（文件指针位置） WqM
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private void read_nPos() i/C% 1<  
{ K:XP;#OsP  
try{ E_'H=QN c  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7jxx,#I:  
int nCount = input.readInt(); yMyvX_UNI  
nStartPos = new long[nCount]; 8kcMgCO  
nEndPos = new long[nCount]; vP#*if[V5  
for(int i=0;i<nStartPos.length;i++) a6xo U;T  
{ +-),E.  
nStartPos = input.readLong(); :J@3:+sr  
nEndPos = input.readLong(); `#W+pO  
} IYtiX  
input.close(); [\eVX`it  
} Tc"J(GWG  
catch(IOException e){e.printStackTrace ();} ,)dlL tUm  
catch(Exception e){e.printStackTrace ();} /zXOtaG  
} nC[aEZ7  
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private void processErrorCode(int nErrorCode) \}4*}Lr  
{ b{aB^a:f=L  
System.err.println("Error Code : " + nErrorCode); 04}8x[t  
} CV=qcD  
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//停止文件下载 2
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public void siteStop() u23_*W\  
{ x'\C'zeF  
bStop = true; g yV>k=B  
for(int i=0;i<nStartPos.length;i++) S:i#|T."  
fileSplitterFetch.splitterStop(); CLmo%"\s  
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} -l_B;Sb:e  
} PW5)") z  
//负责部分文件的抓取 : qK-Rku  
**FileSplitterFetch.java e T;@pc  
*/ EqtL&UHe  
package NetFox; $mAC8a_Zu  
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import java.io.*; RR:%"4M  
import java.net.*; }[lP^Qs  
W 2[]m>;  
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public class FileSplitterFetch extends Thread { Fx.Ly]L  
t_!p({  
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String sURL; //File URL <FU?^
*~  
long nStartPos; //File Snippet Start Position <)!,$]S  
long nEndPos; //File Snippet End Position <"K*O9nst  
int nThreadID; //Thread's ID *U%3[6hm  
boolean bDownOver = false; //Downing is over H#V&5|K%  
boolean bStop = false; //Stop identical vR!g1gI23  
FileAccessI fileAccessI = null; //File Access interface Wq+GlB*  
yZ[g2*1L  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #\=7
A  
{ eCsk\f`  
this.sURL = sURL; [mjie1j/<  
this.nStartPos = nStart; >w7KOVbN3  
this.nEndPos = nEnd; ^<-r57pz  
nThreadID = id; @q>Hl`a  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 V7nOT*N:Q  
} l"}_+5  
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?$)5NQB%  
public void run() RzL(Gnb  
{ |BZrV3;H  
while(nStartPos < nEndPos && !bStop) =+wd"Bu  
{ !dGu0wE  
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 6(-s@{  
try{ gELG/6l  
URL url = new URL(sURL); `?N0?;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^Z;zA@[wt  
httpConnection.setRequestProperty("User-Agent","NetFox"); \B84  
String sProperty = "bytes="+nStartPos+"-"; QM3DB  
httpConnection.setRequestProperty("RANGE",sProperty); z
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Utility.log(sProperty); hchG\i  
m#8[")a$"  
7XyCl&Dc:  
InputStream input = httpConnection.getInputStream(); X|Y(*$?D7  
//logResponseHead(httpConnection); Ky%lu^  
9-{=m+|b  
^s7!F.OC  
byte[] b = new byte[1024]; h ':ZF  
int nRead; 1F5KDWtE  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) e*lL.  
{ M:
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nStartPos += fileAccessI.write(b,0,nRead); ZGR5"el!  
//if(nThreadID == 1) f4Y)GO<R]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); HW~-GcU-o  
} V+lF|CZb5  
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Utility.log("Thread " + nThreadID + " is over!"); Rb0I7~Z%'d  
bDownOver = true; 0]
  
//nPos = fileAccessI.write (b,0,nRead); oS..y($TI  
} io+V4m  
catch(Exception e){e.printStackTrace ();} ]nB|8k=J  
} +Z|3[#W  
} u>:(MARsR  
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//打印回应的头信息 NvJ5[W  
public void logResponseHead(HttpURLConnection con) 1F`jptVQ\G  
{ Px=@Tw N,  
for(int i=1;;i++) 6
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{ -g2l-N{&  
String header=con.getHeaderFieldKey(i); ZzupK^5Z  
if(header!=null) i}DS+~8v  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9/(jY$Ar  
Utility.log(header+" : "+con.getHeaderField(header)); 3)W zX  
else h5@GeYda  
break; u7[}pf$}  
} sg^|dS{3D  
} w(6n  
s b;q)Rh  
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public void splitterStop() P7.b
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{ &R%'s1]o  
bStop = true; ,?|$DY+=  
} OA[e}Vn  
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} \\FT.e
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/* =otO@22Np  
**FileAccess.java /!?LBtqy  
*//文件访问(定位，写) ZKrLp8l\  
package NetFox; [^5;XD:%&l  
import java.io.*; @9B*V~ <  
\CMZ_%~wU  
aaFT   
public class FileAccessI implements Serializable{ ;Nj9,Va(t  
:h{uZ,#Gi  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ccHf+=  
RandomAccessFile oSavedFile; zOs}v{8"  
long nPos; PVo7Sy!'H  
3O/#^~\'hW  
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public FileAccessI() throws IOException y'K2#Y~1e  
{ Tf86CH=)5  
this("",0); pZ.b X  
} C}RO'_Pq  
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XnQR(r)pR2  
public FileAccessI(String sName,long nPos) throws IOException Ku75YFO,5  
{ Oo|PZ_P  
oSavedFile = new RandomAccessFile(sName,"rw"); Ur(R[*2bx  
this.nPos = nPos; (.ir"\k1(  
oSavedFile.seek(nPos); Db,"Gl  
} {rUg,y{v  
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9 %T??-  
public synchronized int write(byte[] b,int nStart,int nLen) "=djo+y  
{ pd|KIs%jl  
int n = -1; Jay"  
try{ \l~^dn}  
oSavedFile.write(b,nStart,nLen); "o&8\KSs  
n = nLen; x=oV!x  
} CF '&Yo  
catch(IOException e) >qmCjY1  
{ Qn!mS[l  
e.printStackTrace (); Q\N*)&Sd<M  
} r=H?fTY<3E  
Q
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return n; .S/5kLul  
} o.{W_k/n  
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} 8W\yM;'  
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/* X7},|cmD_  
**SiteInfoBean.java 8=`L#FkRp  
*/ ).SJ*Re*^I  
package NetFox; [IL*}M!  
0[MYQl`  
@NLcO}  
public class SiteInfoBean { gM&IV{k3  
?b;2PH"  
m\6/:~qWW  
private String sSiteURL; //Site's URL }/cReX,so  
private String sFilePath; //Saved File's Path i2,4:M)CV  
private String sFileName; //Saved File's Name 1RRE{]2v#  
private int nSplitter; //Count of Splited Downloading File VeYT[Us"  
7IX8ck[D  
V?uT5.B2  
public SiteInfoBean() @+gr/Pul
^  
{//nSplitter的缺省值为5 NKu[6J?)  
//default value of nSplitter is 5 >h\y1IrAaG  
this("","","",5); $DL}jH^S  
} q[&Kr+)j  
-s3`mc}*  
qoO`)<  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 'C1lP)S5  
{ ytZo
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sSiteURL= sURL; kxMvOB$  
sFilePath = sPath; $w0TEO!  
sFileName = sName; $DY#04Je\=  
this.nSplitter = nSpiltter; 2J7|y\N,  
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DrK]U}3fh"  
} 0!hr9Y]Lx  
vK',!1]y  
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public String getSSiteURL() o(*\MTt?  
{ *w+'I*QSt~  
return sSiteURL; +\eJxyO  
} v e&d"8+]  
uvId],dQ5  
m$T5lKn}U?  
public void setSSiteURL(String value) gHg=G+Q@  
{  %?ElC  
sSiteURL = value; \|HEe{nA  
} *~#I5s\s!  
]auvtm-[  
b] 5weS-<  
public String getSFilePath() R#T-o,m  
{ >qeDb0  
return sFilePath; (RddR{mX  
} 7%*#M#
(T  
&jE\D^>ko  
I!lDKS,b  
public void setSFilePath(String value) Cv**iW  
{ 1}(22Q;  
sFilePath = value; Q:-T'xk@  
} scg&"s  
V]7/hN-Y}  
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public String getSFileName() 4ud(5m;Rle  
{ /2tA n  
return sFileName; J"`V
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} @<\oM]jX  
bMO^}qR`  
gv*b`cl  
public void setSFileName(String value) OoB|Eh|),  
{ eZ'8JU]  
sFileName = value; L'+bVP{L  
} TM)INo^  
6/UOzV,[  
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public int getNSplitter() gRLt0&Q~  
{ qM\ 2f<)  
return nSplitter; ^^a6 (b  
} 3&hR#;,"X  
;_<~9;  
~KK} $iM  
public void setNSplitter(int nCount) sxNf"C=-.  
{ [D
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nSplitter = nCount; z|#*c5Y9w  
} 1j?P$%p  
} Y~"tL(WfJl  
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Od!)MQ*,  
/* IWv 9!lW  
**Utility.java pN9!  
*/ V(';2[)  
package NetFox; m Q2i$ 0u  
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_2fW/U54_  
public class Utility { ..N6]u  
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M':-f3aT%  
public Utility() V:\:[KcL^  
{ csP4Oq\g[  
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lc,k-}n  
} m?e/MQr  
~74Sq'j9Wt  
//线程睡眠 25X|N=}   
public static void sleep(int nSecond) 7-744wV}Z  
{ (\6E.Z#  
try{ K9N31'  
Thread.sleep(nSecond); h FU8iB`Q  
} }-3 VK%  
catch(Exception e) X=QX9Ux?^  
{ #Vk?  
e.printStackTrace (); "laf:Ty1  
} *AH`ob}  
} 4|x_C-@  
t&?jJ7 (&8  
//日志 "f91YX_)  
public static void log(String sMsg) 2S8;=x}/  
{ <cTX;&0=  
System.err.println(sMsg); HPtMp#`T  
} W@R7CQE@  
Rw+r1vW:A  
)tlj{ 7p  
public static void log(int sMsg) iv*RE9?^  
{ pwo$qs(p  
System.err.println(sMsg); ZF7n]LgSc&  
} g QBS#NY  
} T+Yv5l  
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)1At/
mr  
/* a6Vfd&  
**TestMethod.java [ja^Bhu  
*/ Oo|JIr7i  
package NetFox; b7.7@Ly y  
o/-RGLzAo  
8m0*89HEu  
public class TestMethod { j2G^sj"|  
]]|#+$ ~  
SdnnXEB7  
public TestMethod() )Jt. Z^J<  
{ ///xx/weblogic60b2_win.exe 6ALjM-t=V  
try{ B- @bU@H  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ag'hHF
V  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); klKUX/g  
SiteFileFetch fileFetch = new SiteFileFetch(bean); )Xdq+$w.  
fileFetch.start(); v!I z&M:z  
} )@!fLAT  
catch(Exception e){e.printStackTrace ();} !oH{=.w  
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sc*R:"  
} rWr'+v?  
`l45T~`]$  
c/Pql!h+  
public static void main(String[] args) []>rYZ9bv  
{ jf)cDj2  
new TestMethod(); ';R]`vWFe  
} QGN+f)  
} 7;Ze>"W>  
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