http断点续传简单实现（java)

/* U3>G9g>^B  
**SiteFileFetch.java :v+39  
*/ o_S8fHqjt  
package NetFox; b^1!_1c  
import java.io.*; _?8T'?-1  
import java.net.*; o{/D:B  
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public class SiteFileFetch extends Thread { %NuS!v>  
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SiteInfoBean siteInfoBean = null; //文件信息Bean +Z+]Tqo  
long[] nStartPos; //开始位置 2
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long[] nEndPos; //结束位置 S&yCclM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :(Gg]Z9^8  
long nFileLength; //文件长度 QAr1U7{(.  
boolean bFirst = true; //是否第一次取文件 2KU[Yd  
boolean bStop = false; //停止标志 nX~sVG{Q  
File tmpFile; //文件下载的临时信息 g]S.u8K8m  
DataOutputStream output; //输出到文件的输出流 DY%E&Vd:h  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） -7u4f y{T  
public SiteFileFetch(SiteInfoBean bean) throws IOException -Rmz`yOq}  
{ MCvjdc3:  
siteInfoBean = bean; h c"n?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3OTSLF/  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #'8E%4  
if(tmpFile.exists ()) \;~>AL*  
{ -LF^u;s8&S  
bFirst = false; Tg[+K+b  
read_nPos(); 0YKG`W  
} G
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else m$3&r2vgi  
{ m]85F^R0  
nStartPos = new long[bean.getNSplitter()]; aX~7
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nEndPos = new long[bean.getNSplitter()]; ^ `!6Yax?  
} 5 gE  
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} VE!h!`<k  
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public void run() 3.Y/ZWON  
{ 0HE@L_$;2  
//获得文件长度 Al!P=h  
//分割文件 3AWg43L7  
//实例FileSplitterFetch &
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//启动FileSplitterFetch线程 M!,WU
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//等待子线程返回 \'shnzs  
try{ wzF"^CJ  
if(bFirst) B>Mk "WjQ  
{ Y.ic=<0H  
nFileLength = getFileSize(); +Oo>V~  
if(nFileLength == -1) A@GyKx%x$  
{ `6'fX[j5  
System.err.println("File Length is not known!"); ~%'M[3Rb  
} 0^4Tem@  
else if(nFileLength == -2) )
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{ mIt=r_
  
System.err.println("File is not access!"); Rc @p!Xi  
} rZ<@MV|d  
else lbMb  
{ 4]B(2FR[8  
for(int i=0;i<nStartPos.length;i++) ?me0J3u_  
{ &GX pRo  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); P)4SrqW_  
} b:oB $E  
for(int i=0;i<nEndPos.length-1;i++)  ,_HVPE  
{ WEZ)7H  
nEndPos = nStartPos[i+1]; M1^pf<!s  
} cl[rgj  
nEndPos[nEndPos.length-1] = nFileLength; yy@g=<okt\  
} I;9>$?t[  
} c<|;<8ew  
f
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//启动子线程 Ft'?43J  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D >$9(  
for(int i=0;i<nStartPos.length;i++) jCkYzQUPz  
{ rF'q\tJDz  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3nMXfh/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), n1X7T0'  
nStartPos,nEndPos,i); }<m9w\pA  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w\!aKeP'  
fileSplitterFetch.start(); XI@;;>D1=U  
} )V7bi^r  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SRyAW\*LWU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); r1f##  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !c
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nEndPos = " + nFileLength); s:CsUl|  
// fileSplitterFetch[nPos.length-1].start(); C0J/FFBQ^  
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//等待子线程结束 %8s$l'Q;  
//int count = 0; Xi$2MyRd  
//是否结束while循环 sk6C/ '0:  
boolean breakWhile = false; :@mb.'%*!  
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while(!bStop) O8qA2@,  
{ {wVj-w=<W  
write_nPos(); [_
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Utility.sleep(500); F[5[@y  
breakWhile = true; X|++K;rtfE  
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for(int i=0;i<nStartPos.length;i++) UU~S{!*+L  
{ MF69n,(o  
if(!fileSplitterFetch.bDownOver) i|2CZ  
{ =f4>vo}@k  
breakWhile = false; teIUSB[  
break; VXX7Y?!  
} ei%L[>N  
} Pv@Lx+k  
if(breakWhile) WKek^TW4HE  
break; XnR9/t  
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//count++; SHWD@WLE4  
//if(count>4) g$+ $@~  
// siteStop(); |1!RvW:[!  
} [TRHcz n  
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System.err.println("文件下载结束！"); W!6&T [j>  
} SA!P:Q?h  
catch(Exception e){e.printStackTrace ();} Qu]F<H*Y|  
} ;&=c@>!xP#  
@M=xdZNyJ  
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//获得文件长度 xO3-I@  
public long getFileSize() l7vU{Fd-h^  
{ F)XO5CBK  
int nFileLength = -1; @~1}n/  
try{ },#@q_E  
URL url = new URL(siteInfoBean.getSSiteURL()); J?DJA2o  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4TX~]tEyky  
httpConnection.setRequestProperty("User-Agent","NetFox"); "0Ca;hSLM2  
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int responseCode=httpConnection.getResponseCode(); rW),xfo0  
if(responseCode>=400) LlbRr.wL  
{ HX}9;O  
processErrorCode(responseCode); f i#p('8  
return -2; //-2 represent access is error qGivR
DR$  
} O S?S$y  
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String sHeader; tg5G`P5PJ  
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% XvJJ  
for(int i=1;;i++) ;fiH=_{us  
{ 2":{3=oW~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %OT}r  
//Utility.log(in.readLine()); {&3{_Ml  
sHeader=httpConnection.getHeaderFieldKey(i); S1SsJo2\  
if(sHeader!=null) 5|:t$  
{ }:SWgPfc  
if(sHeader.equals("Content-Length")) JA!?vs  
{ h_*!cuH  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <e)u8+(  
break; 7:Cq[u fl  
} mqrV:3}  
} 7j,u&%om  
else 7^bde<0  
break; aI^Z0[P+  
} mssCnr;  
} u"hv _ml  
catch(IOException e){e.printStackTrace ();} V;@kWE>3  
catch(Exception e){e.printStackTrace ();} 'jnR<>N  
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Utility.log(nFileLength); $-4 Zi  
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return nFileLength; OUM^u*  
} b_v{QE<  
|g)/6jG<-  
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//保存下载信息（文件指针位置） mto=_|gn  
private void write_nPos() T>P[0`*)  
{ lX)ZQY:=:  
try{ SOg>0VH)  
output = new DataOutputStream(new FileOutputStream(tmpFile)); aWg*f*2f  
output.writeInt(nStartPos.length); JnodDH ?  
for(int i=0;i<nStartPos.length;i++) )y#~eYn  
{ )\3 RR.p  
// output.writeLong(nPos); J>w3>8!>7  
output.writeLong(fileSplitterFetch.nStartPos); <<vT"2Q]  
output.writeLong(fileSplitterFetch.nEndPos); sQl`0|VH  
} %Eq4>o?D  
output.close(); P&$ m2^K  
} }}s.0Q  
catch(IOException e){e.printStackTrace ();} AhA4IOG`.  
catch(Exception e){e.printStackTrace ();} hH.X_X?d%  
}
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//读取保存的下载信息（文件指针位置） +-$Hx5  
private void read_nPos() ~[*\YN);  
{ $C.;GUEQ  
try{ 6R=dg2tKT  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); GeydVT-  
int nCount = input.readInt(); MGbl-,]  
nStartPos = new long[nCount]; T*3>LY+bb  
nEndPos = new long[nCount]; #Y>os3]  
for(int i=0;i<nStartPos.length;i++) I7C*P~32{n  
{ N"k IQe*}1  
nStartPos = input.readLong(); I
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nEndPos = input.readLong(); %pd-{KR  
} hW Va4  
input.close(); t
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} !Zi_4 .(4  
catch(IOException e){e.printStackTrace ();} HAca'!p  
catch(Exception e){e.printStackTrace ();} UB9n7L(@c  
} _$vAitUe4S  
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private void processErrorCode(int nErrorCode) KEfx2{k b  
{ rEfo)jod  
System.err.println("Error Code : " + nErrorCode); 3v?R"2\qS  
} aePLP  
|,)=-21&;  
9V/:1I0?&0  
//停止文件下载 \2U FJ  
public void siteStop() _*1{fvv0{  
{ >0c4C<_  
bStop = true; @b]?Gg  
for(int i=0;i<nStartPos.length;i++) N*$L#L$*  
fileSplitterFetch.splitterStop(); V/,@hv`+  
"tX=^4
 
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} {37v.4d;  
} 9]]isE8r  
//负责部分文件的抓取 CtO;_;eD'  
**FileSplitterFetch.java B\mRHV!  
*/ h
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package NetFox; [OU[i(,{  
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import java.io.*; =ICakh!TO  
import java.net.*; A@81wv  
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public class FileSplitterFetch extends Thread { @b@# o  
:`X!no; {  
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String sURL; //File URL lXnzomU  
long nStartPos; //File Snippet Start Position m2esVvP  
long nEndPos; //File Snippet End Position ^V;h>X|  
int nThreadID; //Thread's ID b,r{wrLe)  
boolean bDownOver = false; //Downing is over XUK!1}  
boolean bStop = false; //Stop identical knb 9s`wR  
FileAccessI fileAccessI = null; //File Access interface UD6:X&Un  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException </B<=tc  
{ duT'$}2@>  
this.sURL = sURL; HA#9y;\  
this.nStartPos = nStart; kS)azV  
this.nEndPos = nEnd; yZc_PC`  
nThreadID = id; 0*{2
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 *rH#k?  
} ;GF+0~5>  
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public void run() _Gb O>'kE  
{ X={Z5Xxr"  
while(nStartPos < nEndPos && !bStop) "'@>cJ=  
{ [,?5}
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try{ +ebmve \+  
URL url = new URL(sURL); appWq}db  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^0T DaZDLp  
httpConnection.setRequestProperty("User-Agent","NetFox"); )/mBq#ZS  
String sProperty = "bytes="+nStartPos+"-"; d")TH3pG  
httpConnection.setRequestProperty("RANGE",sProperty); A.wuB  
Utility.log(sProperty); yc:y}"  
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InputStream input = httpConnection.getInputStream(); mLb>*xt$b@  
//logResponseHead(httpConnection); >Y8\I  
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byte[] b = new byte[1024]; 6(=>!+xpRr  
int nRead; -?}Z0e(w
 
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &cuDGo.  
{ k,GAHM"'  
nStartPos += fileAccessI.write(b,0,nRead); Q*K31Ln  
//if(nThreadID == 1) !U[/P6 +0  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "xxt_  
} S|pf.l  
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Utility.log("Thread " + nThreadID + " is over!"); '5; /V  
bDownOver = true;  U rL|r.  
//nPos = fileAccessI.write (b,0,nRead); LZ-&qh  
} LAjreC<W  
catch(Exception e){e.printStackTrace ();} RIV + _}R  
} n5s2\(  
} bg/a5$t  
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//打印回应的头信息 t;/s^-}  
public void logResponseHead(HttpURLConnection con) ic=tVs  
{ H9+[T3b  
for(int i=1;;i++) /]>8V'e\  
{ $ts1XIK%  
String header=con.getHeaderFieldKey(i); ,(y6XUV~  
if(header!=null) pr.+r?la]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0hv}*NY
d  
Utility.log(header+" : "+con.getHeaderField(header)); 45aFH}w:  
else ApSzkPv*  
break; 4qvE2W}&  
} ZgI?#e  
} efXiZ  
#BhDC.CcW  
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public void splitterStop() lNbAt4]}f(  
{ Rn9e#_Az  
bStop = true; H7?Sd(U  
} q<Z`<e  
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} DNu-
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/{%p%Q[X  
/* A(}D76o_  
**FileAccess.java IlfH  
*//文件访问(定位，写) k^Qd%;bdF  
package NetFox; Z3q
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import java.io.*; AQm#a;  
>hv8zHOO:  
E x)fXQ+  
public class FileAccessI implements Serializable{ FXG,DJ:  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 o>75s#= b=  
RandomAccessFile oSavedFile; M.u1SB0  
long nPos; b-
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public FileAccessI() throws IOException a%*W( 4=Y  
{ vf0 fa46  
this("",0); |*>s%nF|  
} #I}w$j i  
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public FileAccessI(String sName,long nPos) throws IOException <TEDqQ  
{ 9][A1+"  
oSavedFile = new RandomAccessFile(sName,"rw"); d A>6  
this.nPos = nPos; D $&6 8  
oSavedFile.seek(nPos); .
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} XE($t2x,M  
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public synchronized int write(byte[] b,int nStart,int nLen) Vi<6i0  
{ ,u S)N6'b6  
int n = -1; FM,o&0HSd  
try{ '4)4*3
z,  
oSavedFile.write(b,nStart,nLen); ,Q,3^v-  
n = nLen; e!N%  
} Y,M2D  
catch(IOException e) b NR@d'U  
{ 2Kz407|'  
e.printStackTrace (); /RemLJP F  
} ^KUM4. 6  
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return n; auHP^O>4L  
} 0w!:YB,}  
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} siz:YRur  
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/* Jix;!("  
**SiteInfoBean.java ODCv^4}9  
*/ b&P2VqYgl  
package NetFox; @m+FAdA 0  
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public class SiteInfoBean { TXbnK"XQ  
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private String sSiteURL; //Site's URL
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private String sFilePath; //Saved File's Path 9E2OCLWrE  
private String sFileName; //Saved File's Name /NUu^ N  
private int nSplitter; //Count of Splited Downloading File %9b TfX"  

!~`aEF3  
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public SiteInfoBean() `P jS  
{//nSplitter的缺省值为5 T854}RX[{  
//default value of nSplitter is 5 IeAUVRS)  
this("","","",5); Xu& v3Y~k  
} qJK-HF:#  
N**"u"CX  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ^~W s4[Guo  
{ GB{Q)L  
sSiteURL= sURL; , %A2wV  
sFilePath = sPath; )F m'i&F_  
sFileName = sName; } QpyU%  
this.nSplitter = nSpiltter; 3Gt@Fo=  
#C+7~ns'  
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} V PI_pK  
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I_  
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public String getSSiteURL() qbKcI+)47  
{ YJ{_%z|U  
return sSiteURL; q],/%W  
} # 66vkf*  
j1K?QH=e#{  
>=YQxm}GJ  
public void setSSiteURL(String value) b X4]/4%  
{ lB(P+yY,/'  
sSiteURL = value; ~`<_xIvrq  
} 23'Ac,{  
}u.1$Y  

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public String getSFilePath() %:Y'+!bX  
{ W<M\b#  
return sFilePath; UQ~gjnb[c  
} [t"#4[  
G&#l3bkQ  
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public void setSFilePath(String value) ^K[[:7Aem  
{ 4_w{
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sFilePath = value; |VmQ  
} J-W8wCq`  
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public String getSFileName() Z(hRwIOF  
{ I ka V g L  
return sFileName; >:P-3#e*  
} 6B@{X^6y  
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public void setSFileName(String value) +A<7:`sO  
{ p"QV| `  
sFileName = value; '/@i} digf  
} `W{y  
M~-jPY,+  

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public int getNSplitter() C[nacAi  
{ A#CGD0T  
return nSplitter; xcC^9BAj  
} 7jYW3  
:+UahwiRD"  
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public void setNSplitter(int nCount) <%=@Ue  
{ zN>tSdNkI-  
nSplitter = nCount; H)NT2@%{P  
} T@j@IEGH  
}
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qWw{c&{Q],  
/* O],]\M{GL  
**Utility.java 7-[^0qS  
*/ U&L?IT=x  
package NetFox; UE 
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v v]rXJu1  
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public class Utility { ItwJL`  
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public Utility() z+X DN:  
{ )}4xmf@gl  
cfUG)-]P~  
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} i`EG80\[Z  
qh/}/Sl;  
//线程睡眠 H6i;MQ  
public static void sleep(int nSecond) ZvkBF9d  
{ {WN??eys,  
try{ wj|[a,(r  
Thread.sleep(nSecond); CYN")J8V  
} _rfGn,@BH  
catch(Exception e) 2qDVAq^@  
{ ( 2i{8  
e.printStackTrace (); Y1L7sH 9  
} 0 A6%!h  
} 7A4_b8  
K5:>  
//日志 z#t;n  
public static void log(String sMsg) IGcYPL\&  
{ Un{9reX5  
System.err.println(sMsg); @M8vPH  
} [h~#5x  
T|ZJ
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public static void log(int sMsg) U$AV"F&!&}  
{ ^3w >:4m  
System.err.println(sMsg); |f<-lB[k  
} HbQ+:B]  
} Hy#<f
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m>LC2S; f  
/* [qQ~\]  
**TestMethod.java <wO8=bem  
*/ F
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package NetFox; c_)lTI4  
w$z]Z-  
L(\o66a-rV  
public class TestMethod { bs\7 juHt  
OjBg$f~0F  
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public TestMethod() Afo qCF  
{ ///xx/weblogic60b2_win.exe z*O
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try{ 4: S-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); A<P rsk!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); v="2p8@F  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Nk&$b  
fileFetch.start(); ul[+vpH9  
} Q*
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catch(Exception e){e.printStackTrace ();} +
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} +
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`=VN\W^&  
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public static void main(String[] args) Y+ea  
{ FvV:$V|  
new TestMethod(); rT{+ h}vO  
} Z{spo=  
} [{cMEV&  
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