http断点续传简单实现（java)

/* M MAA
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**SiteFileFetch.java PM~bM3Ei  
*/ $Hp.{jw  
package NetFox; j';n8|Y9  
import java.io.*; $42Au2Jg  
import java.net.*; E7rX1YdR  
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public class SiteFileFetch extends Thread { H9%l?r5  
*I:mw8t  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 13ipaz  
long[] nStartPos; //开始位置 4dW3'"R"L  
long[] nEndPos; //结束位置 yDd=& T   
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4JGE2ArR  
long nFileLength; //文件长度 xJvLuzUD  
boolean bFirst = true; //是否第一次取文件 u=vh Z%A]  
boolean bStop = false; //停止标志 8W-]t1O%!  
File tmpFile; //文件下载的临时信息 }US7Nw  
DataOutputStream output; //输出到文件的输出流 uyL72($  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =MMCf0  
public SiteFileFetch(SiteInfoBean bean) throws IOException HS{P?~:=U  
{ M'^(3#ZU  
siteInfoBean = bean; 54=}GnZN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -"F0eV+y  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8dc538:q}  
if(tmpFile.exists ()) _kh>Z  
{ BiA>QQ  
bFirst = false; Ru)(dvk
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read_nPos(); e@[9C(5E"  
} >RM 0=bO  
else [/?c@N,  
{ v-ThdE$G#  
nStartPos = new long[bean.getNSplitter()]; ^[en3aQ  
nEndPos = new long[bean.getNSplitter()]; 6/|U  
} Y.E?;iS
  
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} bKYY{V55  
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public void run() KZECo1  
{ 5QR}IxQ  
//获得文件长度 GXO4x|08F  
//分割文件 *0O<bm  
//实例FileSplitterFetch
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//启动FileSplitterFetch线程 'w}p[(  
//等待子线程返回 JdtPY~k0  
try{ <R>Q4&we(  
if(bFirst) NvcHv7,  
{ 9KXym
}  
nFileLength = getFileSize(); QS\Uq(Ja\  
if(nFileLength == -1)
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{ SAP;9*f1\  
System.err.println("File Length is not known!"); 8AryIgy>@  
} D^nxtuT*  
else if(nFileLength == -2) >Z}@7$(7!~  
{ ja?s@Y}-9s  
System.err.println("File is not access!"); VW{,:Ya  
} }bp.OV-+  
else 3a%xn4P  
{ 5|CzX X#U  
for(int i=0;i<nStartPos.length;i++) U>oW~Z  
{ 0k%hY{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 'X54dXS?l  
} }0Y`|H\v  
for(int i=0;i<nEndPos.length-1;i++) NJ<N%hcjK  
{ `y'aH 'EEd  
nEndPos = nStartPos[i+1]; ?<E0zM+  
} :aH%bk  
nEndPos[nEndPos.length-1] = nFileLength; MZ)T0|S_  
} AhR0zg  
} ~,T+JX  
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//启动子线程 goB;EWz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; gd K*"U  
for(int i=0;i<nStartPos.length;i++) F,zG;_  
{ _1P`]+K\D$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PzLJ/QER  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), YN/u9[=`  
nStartPos,nEndPos,i); C*a,<`
  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `T=1<Twc  
fileSplitterFetch.start(); $}db /hY*  
} 9T$u+GX'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V#NtBreN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  ER_ 3'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ",
 b)Tl*  
nEndPos = " + nFileLength); >zFD$  
// fileSplitterFetch[nPos.length-1].start(); B_cgWJ*4  
:Z[(A"dA  
~U9q-/(J/  
//等待子线程结束 4Ppop  
//int count = 0; &;s<dDQK  
//是否结束while循环 SAy{YOLtl  
boolean breakWhile = false; s047"Q  
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while(!bStop) i$["aP~G  
{ D!S8oKW  
write_nPos(); ^@K WYAAW5  
Utility.sleep(500); rEmwKZF'  
breakWhile = true; Si]X rub  
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for(int i=0;i<nStartPos.length;i++) p=vV4C:  
{ 'aZASPn[  
if(!fileSplitterFetch.bDownOver) S_$nCyaH2  
{ eKyqU9  
breakWhile = false; SetX#e?q~  
break; p.5e: i^LJ  
} 2Y$  
} :kt/$S^-  
if(breakWhile) a>w~FUm*  
break; 9
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//count++; j$mz3Yk  
//if(count>4) 0X#+#[W  
// siteStop(); !U
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} \OT6L'l],  
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System.err.println("文件下载结束！"); k/@Tr
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} NZP7r;u  
catch(Exception e){e.printStackTrace ();} =-5[Hn%  
} @i{]4rk lv  
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//获得文件长度 &Q~)]|t  
public long getFileSize() UhdqY]  
{
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int nFileLength = -1; Fo(y7$33*  
try{ uRpBeH]Z"  
URL url = new URL(siteInfoBean.getSSiteURL()); S2Vxe@b)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F)7j@h^
 
httpConnection.setRequestProperty("User-Agent","NetFox"); 9$wAm89  
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int responseCode=httpConnection.getResponseCode(); c})wD+1  
if(responseCode>=400) u-:MVEm  
{ LZa% x  
processErrorCode(responseCode); xj7vI&u.  
return -2; //-2 represent access is error n$xszuNJ`  
} MOeoU1Hn  
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String sHeader; 5VZjDg?  
7DZTQUb"  
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for(int i=1;;i++) ntZ~m  
{ "[.ne)/MC  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +KP_yUq[  
//Utility.log(in.readLine()); fK"iF@=Z`  
sHeader=httpConnection.getHeaderFieldKey(i); qX?[mdCHZ  
if(sHeader!=null) 7O$ &  
{ >4c`UW  
if(sHeader.equals("Content-Length")) &oEyixe  
{ fbV@=(y?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));
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break; OJ>iq@>  
} WN\PX!K9  
} 6+e4<sy[E  
else {Zl4C;c  
break; h7*O.Opm=  
} zofx+g\(W  
} UKj`_a6  
catch(IOException e){e.printStackTrace ();} =Epq%,4nG  
catch(Exception e){e.printStackTrace ();} hkF^?AJ  
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Utility.log(nFileLength); QF&6?e06p0  
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return nFileLength; _#vGs:-x&  
} ^)<w*iqBD  
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//保存下载信息（文件指针位置） {=iyK/Uf  
private void write_nPos() O2lIlCL  
{ }lO }x  
try{ 4 4`WYK l  
output = new DataOutputStream(new FileOutputStream(tmpFile)); |]tZ hI"3<  
output.writeInt(nStartPos.length); XWXr0>!,?  
for(int i=0;i<nStartPos.length;i++) I=odMw7Hj  
{ 7>&1nBh. f  
// output.writeLong(nPos); }LQ\a8]<
 
output.writeLong(fileSplitterFetch.nStartPos); WUY,. 8  
output.writeLong(fileSplitterFetch.nEndPos); RY<%'\A`~  
} [xf$VkjuF  
output.close(); IM]h*YV'  
} O8y9dX-2  
catch(IOException e){e.printStackTrace ();} C=[A
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catch(Exception e){e.printStackTrace ();} ~1ps7[  
} >f%,`r  
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//读取保存的下载信息（文件指针位置） u#3)p  
private void read_nPos() ,5w]\z  
{ :q;R6-|.  
try{ Q1]Wo9j  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); *{nunb>WO  
int nCount = input.readInt(); O4!9{  
nStartPos = new long[nCount]; X Ny Y$  
nEndPos = new long[nCount]; ZRPy~wy>  
for(int i=0;i<nStartPos.length;i++) j.B>v\b_3  
{ f~R[&q+  
nStartPos = input.readLong(); A_i zSzC1  
nEndPos = input.readLong(); bBG/gQ  
} N6q5`Ry  
input.close(); {#9,j]<  
} qy&\Xgn;GA  
catch(IOException e){e.printStackTrace ();} J'Gm7h{   
catch(Exception e){e.printStackTrace ();} gi1j/j7  
} Oq}ip  
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private void processErrorCode(int nErrorCode) om>VQ3  
{ Ko+al{2  
System.err.println("Error Code : " + nErrorCode); Q0WY$w1<  
} x G^f  
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//停止文件下载 "
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public void siteStop() 3(o7co-f  
{ fB7ljg  
bStop = true; <5k&)EoT  
for(int i=0;i<nStartPos.length;i++) F^miq^K=  
fileSplitterFetch.splitterStop(); DyIV/  
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} 3>M.]w6{  
} }7Jp :.qk  
//负责部分文件的抓取 >>j+LRf*  
**FileSplitterFetch.java qw2)v*Fn  
*/ C/  
package NetFox; )vQNiik#  
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import java.io.*; {KsVK4\r  
import java.net.*; F:_F
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public class FileSplitterFetch extends Thread { L&QtHSzy  
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String sURL; //File URL #<UuI9  
long nStartPos; //File Snippet Start Position AoIc9ElEX  
long nEndPos; //File Snippet End Position u]0!|Jd0  
int nThreadID; //Thread's ID zu<>"5}]  
boolean bDownOver = false; //Downing is over :v#8O~
  
boolean bStop = false; //Stop identical RyE_|]I62u  
FileAccessI fileAccessI = null; //File Access interface 77tZp @>hn  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException WSS(Bm|B  
{ sSV^5  
this.sURL = sURL; 4rm87/u*0  
this.nStartPos = nStart; )%BT*)x  
this.nEndPos = nEnd; X
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nThreadID = id; w0aHEvH/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7> )l{7  
} jOtzx"/)rE  
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public void run() PK8V2Ttv  
{ Rd0?zEKV  
while(nStartPos < nEndPos && !bStop) B]i+,u  
{ h~ZNHSP:  
"~Us#4>  
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try{ 7F~xq#Wi#  
URL url = new URL(sURL); j~.u>4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); jWh
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httpConnection.setRequestProperty("User-Agent","NetFox"); yG4MUf6  
String sProperty = "bytes="+nStartPos+"-"; sE}sE=\  
httpConnection.setRequestProperty("RANGE",sProperty); ^&HI+M  
Utility.log(sProperty); X!m;uJZp  
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InputStream input = httpConnection.getInputStream(); ~O8]3+U  
//logResponseHead(httpConnection); y^3,X_0  
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byte[] b = new byte[1024]; %$^$'6\77  
int nRead; 95VqaR,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  r^e-.,+  
{ RBPYGu'6B  
nStartPos += fileAccessI.write(b,0,nRead); ga,
A'Z  
//if(nThreadID == 1) #i6[4X?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R+C+$?4NG  
} %uF:)  
 POkXd^pI  
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Utility.log("Thread " + nThreadID + " is over!"); ;>sq_4_  
bDownOver = true; []!tT-Gzy  
//nPos = fileAccessI.write (b,0,nRead); cz$c)It  
} jjNxatAN  
catch(Exception e){e.printStackTrace ();} H9/XW6W,"w  
} EccFx7h  
} g}^4^88=a  
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//打印回应的头信息 /]P%b K6B  
public void logResponseHead(HttpURLConnection con) 3KbUHSx  
{ ~rp.jd 0l  
for(int i=1;;i++) 'w:tq  
{ hl=oiUf[s  
String header=con.getHeaderFieldKey(i); DM+sjn  
if(header!=null) 65 NWX8f}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); J*/$ywI  
Utility.log(header+" : "+con.getHeaderField(header)); ;I[.  
else zjzqKdy}F  
break; @:I\\S@bN  
} 4+ykE:  
} [<,0A]m   
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public void splitterStop() }x>}:"P;W  
{ bwv/{3G,Ys  
bStop = true; K%o6hBlk_  
} T "ZQPLg  
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} %jYQ  
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/* yN%3w0v  
**FileAccess.java }mkA Hmu4  
*//文件访问(定位，写) q=(M!9cE  
package NetFox; t"jIfU>'a/  
import java.io.*; EY=\C$3J:  
y=y/d>=w  
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public class FileAccessI implements Serializable{ ;F" kD  
}?\#_BCjx(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 30wYc &H  
RandomAccessFile oSavedFile; o;HdW  
long nPos; h'z+8X_t  
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public FileAccessI() throws IOException /TR"\xQF  
{ qJe&jLZa  
this("",0); i'[n`|c<  
} A?%XO %  
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public FileAccessI(String sName,long nPos) throws IOException S}XB |  
{ 1t} (+NNjH  
oSavedFile = new RandomAccessFile(sName,"rw"); o+PQ;Dl  
this.nPos = nPos; HY@kw>I  
oSavedFile.seek(nPos); R]V~IDs   
} Xuz8"b5^Zx  
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public synchronized int write(byte[] b,int nStart,int nLen) 98"z0nI%  
{ sYW1T @  
int n = -1; 4okHAv8;  
try{ LrmtPnL  
oSavedFile.write(b,nStart,nLen); dT*
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n = nLen; (9'G  
} o}j_eHl{  
catch(IOException e) 'Kt4O9=p  
{ ePIly)=X  
e.printStackTrace (); $A5B{2  
} soFvrl^Ql+  
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return n; 7k[`]:*o  
} d6Q :{!Sd"  
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} vh:UXE lm  
^HOwN<}`#  
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/* ePu2t3E  
**SiteInfoBean.java ps{&WT3a  
*/ j|VlHDqR  
package NetFox; eX]9mQ]E  
,&O:/|c E  
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public class SiteInfoBean { *n$m;yI  
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private String sSiteURL; //Site's URL (pRy1DH~  
private String sFilePath; //Saved File's Path Rzn0-cG  
private String sFileName; //Saved File's Name D{Jc+Q$  
private int nSplitter; //Count of Splited Downloading File t"!8
 
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public SiteInfoBean() xYzcV%-Pm  
{//nSplitter的缺省值为5 \e5,`  
//default value of nSplitter is 5 JVIcNK)  
this("","","",5); "8C(_z+]K`  
} k*UR#z(I  
:BrnRW64  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )oz-<zW  
{ e
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sSiteURL= sURL; j_YZ(: =  
sFilePath = sPath; 5D02%U2N)G  
sFileName = sName; G3^n_]Jb  
this.nSplitter = nSpiltter; 2=UTH%1D  
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} H?zCI
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public String getSSiteURL() )eedfb1
  
{ %]= 'Uv^x  
return sSiteURL; 2Yg[8Tm#  
} bQ:3G;  
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1PT_1[eAR  
public void setSSiteURL(String value) A?{aUQB~|  
{ t9-\x  
sSiteURL = value; Fy+7{=?^F  
} 3!L<=X  
-^nQ^Td=j  
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public String getSFilePath() JD\-X(O  
{ ;]`NR  
return sFilePath; JXa%TpI: E  
} N6 }i>";_;  
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public void setSFilePath(String value) #.t$A9'  
{ u3?Pp[tM<  
sFilePath = value; Wn9Mr2r!*,  
} )*QTxN  
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+ 1%^c(3  
public String getSFileName() =jd=Qs IL
 
{ pa> 2JF*  
return sFileName; 1_E3DXe  
} :92a34  
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public void setSFileName(String value) #L*@~M^]  
{ %cjGeS6}  
sFileName = value; KL_}:O68  
} /n3&e  
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public int getNSplitter() f`";
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{ moM&2rgdrQ  
return nSplitter; _/w-gL{  
} b+#~N>|  
@^4M~F%  
}T*xT>p^3  
public void setNSplitter(int nCount) W;@ae,^  
{ R8W44I*R:  
nSplitter = nCount; 1Qe!  
} u2x=YUWb]  
} !{ )AV/\D  
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,8 NEnB  
/* l$~bk
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**Utility.java 7|eSvC  
*/ +Q#Qu0_   
package NetFox; _w,0wn9N$  
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public class Utility { s/&]gj"  
#3[b|cL  
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public Utility() %_=R&m'n`  
{ U=#ylQ   
-/{}^QWB  
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} Jt, 4@  
s=@CeV@4W  
//线程睡眠 Ewsg&CCN  
public static void sleep(int nSecond) I\6<)2j/L  
{ DT]p14@t9  
try{ \osQwGPV  
Thread.sleep(nSecond); :T
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} +&8Ud8Q  
catch(Exception e) :\;uJ5  
{ ->9xw  
e.printStackTrace (); g~D6.OZU  
} Gv3Fg[MA@c  
} /g7?,/vnZ  
6zZR:ej  
//日志 (eE}W~Z  
public static void log(String sMsg) ' 1]bjW*!  
{ #]/T9:  
System.err.println(sMsg); }? '9L:  
} =v=!x  
yQ&%* ?J  
1b%7FrPkd  
public static void log(int sMsg) R'HA>?D  
{ \ OINzfbr  
System.err.println(sMsg); i1Sc/  
} O7*i;$!R  
} 3s$.l}  
To? bp4  
yC*BOJS  
/* 1)r_h(  
**TestMethod.java ^TuEp$Z=  
*/ ]+7c1MB(5  
package NetFox; O +}EE^*a  
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public class TestMethod { oT{yttSNo  
9yAu<a  
;!sGfrs0$  
public TestMethod() r@UY$z  
{ ///xx/weblogic60b2_win.exe 0! %}  
try{ `bF;Ew;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =_6h{f&Q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <s3(
  
SiteFileFetch fileFetch = new SiteFileFetch(bean); n{WJ.Y*  
fileFetch.start(); 9?,.zc
^  
} *9wHH-#  
catch(Exception e){e.printStackTrace ();} U {!{5l:  
^}\R]})w"  
]arskmB]  
} s4k%ty}  
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public static void main(String[] args) $zi\ /Yw  
{ SnU{ZGR>sP  
new TestMethod(); c)fp;^  
} 8{t&8Ql n  
} 6^u(PzlA|~  
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