http断点续传简单实现（java)

/* Ud(`V:d  
**SiteFileFetch.java b[ w;i]2  
*/ &#
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package NetFox; E-2eOT  
import java.io.*; KY9n2u&4  
import java.net.*; =:I+6PlF@  
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public class SiteFileFetch extends Thread { Yl^mAS[w&  
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SiteInfoBean siteInfoBean = null; //文件信息Bean Gh( A%x)  
long[] nStartPos; //开始位置 t?eH
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long[] nEndPos; //结束位置 @%ECj)u`O  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 f'Mop= .  
long nFileLength; //文件长度 ,_ 2x{0w:>  
boolean bFirst = true; //是否第一次取文件
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boolean bStop = false; //停止标志 Bi%x`4Lf  
File tmpFile; //文件下载的临时信息 1NLg _UBOK  
DataOutputStream output; //输出到文件的输出流 `ldz`yu6++  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 2DDsWJ;  
public SiteFileFetch(SiteInfoBean bean) throws IOException \?fIt?  
{ } p:%[  
siteInfoBean = bean;
%&<LNEiUN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (P|pRVO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !nf-}ze{  
if(tmpFile.exists ()) t+Bf#:  
{ 8?FueAM'  
bFirst = false; GZ#aj|  
read_nPos(); ]$iqa"{  
} ?h8{xa5b  
else 8{ c!).  
{ 2f:^S/.A  
nStartPos = new long[bean.getNSplitter()]; ]ZoPQUS?  
nEndPos = new long[bean.getNSplitter()];  $)~   
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} cntco@  
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public void run() s][24)99  
{ Tny>D0Z#  
//获得文件长度 
&:#h$`4  
//分割文件 =6nD sibf  
//实例FileSplitterFetch 5jcte< 5I_  
//启动FileSplitterFetch线程 $7Jo8^RE  
//等待子线程返回 L@Nu/(pB=  
try{ LRb,VD:/Y  
if(bFirst) 4_?7&G0(  
{ 'fd1Pj9~$  
nFileLength = getFileSize(); ib6^x:HGU  
if(nFileLength == -1) AONDx3[   
{ 2'0K WYM  
System.err.println("File Length is not known!"); a:STQk V  
} |AZ
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else if(nFileLength == -2) mh/n.*E7  
{ 4Ft1@  
System.err.println("File is not access!");  Ukz;0q  
} V4w=/e_  
else Rd*[%)  
{ oA-:zz>wL  
for(int i=0;i<nStartPos.length;i++) #\rwLpC1u  
{ X@2-*so<
 
nStartPos = (long)(i*(nFileLength/nStartPos.length));
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} Zo-$z8  
for(int i=0;i<nEndPos.length-1;i++) },$0&/>ft  
{ g{k1&|  
nEndPos = nStartPos[i+1]; ]3{0J  
} :3h{ A`u  
nEndPos[nEndPos.length-1] = nFileLength; v6(E3)J7  
} 256LHY|6  
} y2L#:[8  
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//启动子线程 m` AK~O2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; D=f7NVc>Q  
for(int i=0;i<nStartPos.length;i++) : esg(  
{ z,SYw &S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Aj>[z8!,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }GwVKAjP  
nStartPos,nEndPos,i); Ka!I`Yf  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I<oL}f  
fileSplitterFetch.start(); >`RRP}u=u  
} Ut@RGg+f8  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >H][.@LyR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \*T"M*;  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", OR6ML-|  
nEndPos = " + nFileLength); jyS=!ydn+  
// fileSplitterFetch[nPos.length-1].start(); fK}h"iH+K  
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)Q;978:  
//等待子线程结束 M)-6T{[IT  
//int count = 0; \ gwXH  
//是否结束while循环 J97R
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boolean breakWhile = false; &n2e  
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while(!bStop) (46 {r}_O  
{ :;;E<74e i  
write_nPos(); DPgm%Xq9(!  
Utility.sleep(500); 6c4&VW
  
breakWhile = true; 'fV%Z  
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for(int i=0;i<nStartPos.length;i++) imB#Eo4eY  
{ 5v.DX`"  
if(!fileSplitterFetch.bDownOver) <~U4*  
{ M5L{*>4|6  
breakWhile = false; R{Z-m2La  
break; 66&EBX}  
} >zvY\{WY  
} IV16d  
if(breakWhile) RSfM]w}Hq#  
break; +ZsX*/TOn  
Z$KLl((  
-!M,75nU  
//count++; g:ErZ;[  
//if(count>4) 6SM:x]`##,  
// siteStop(); Nt`b;X&  
} ;#+0L$<t  
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W  
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System.err.println("文件下载结束！"); b}9[s  
} }l0&a!C  
catch(Exception e){e.printStackTrace ();} | $^;wP  
} U 5w:"x  
z$lF)r:Bc  
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//获得文件长度 5MTgK=c  
public long getFileSize() Lm*VN~2  
{ CJknJn3m&  
int nFileLength = -1; I+ l%Sn#\  
try{ ^>&k]T`  
URL url = new URL(siteInfoBean.getSSiteURL()); `g''rfk}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9<Eg}Ic  
httpConnection.setRequestProperty("User-Agent","NetFox"); rZ1Hf11C  
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int responseCode=httpConnection.getResponseCode(); ?8@>6IXn  
if(responseCode>=400) LE^G&<!  
{ FyL_xu\e  
processErrorCode(responseCode); -4#2/GXNO  
return -2; //-2 represent access is error kYwb -;  
} 1$lh"fHU  
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String sHeader; )ukpJ z""  
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for(int i=1;;i++) ~ AQp|  
{ 3:/'n  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9%)=`W  
//Utility.log(in.readLine()); O09ke-lC  
sHeader=httpConnection.getHeaderFieldKey(i); ,1{Ep`
 
if(sHeader!=null) hqSJ(gs{  
{ !/{+WHxIr|  
if(sHeader.equals("Content-Length")) C_fY %O  
{
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); f7de'^t9  
break; zzGYiF?  
} I8Vb-YeS  
} <3X7T6_:@  
else Rhzn/\
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break; T5Eseesp  
} iX{G]< n  
} 1t[j"CG(o  
catch(IOException e){e.printStackTrace ();} :VmHfOO  
catch(Exception e){e.printStackTrace ();} {NM+Oj,~'  
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Utility.log(nFileLength); 0o&MB Dp  
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return nFileLength; 1r)kR@!LNG  
} YA(@5CZ  
+A_J1iJ<  
H(^bC5'  
//保存下载信息（文件指针位置） $3+PbYY  
private void write_nPos() m(OvD!  
{  r}_c  
try{ *~$~yM/~3U  
output = new DataOutputStream(new FileOutputStream(tmpFile)); { >{B`e`$  
output.writeInt(nStartPos.length); ) iQ   
for(int i=0;i<nStartPos.length;i++) _>o-UBb4]T  
{ w2(guL($  
// output.writeLong(nPos); 6$Q,Y}j  
output.writeLong(fileSplitterFetch.nStartPos); h( QYxI,|  
output.writeLong(fileSplitterFetch.nEndPos); 3*S{;p  
} uZKP"Oy  
output.close(); ?ne
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} 2LY=DL7  
catch(IOException e){e.printStackTrace ();} R! s6% :Yg  
catch(Exception e){e.printStackTrace ();} oSb, :^Wl  
} >n5:1.g  
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{1J&xoV"  
//读取保存的下载信息（文件指针位置） a)-FGP^  
private void read_nPos() w>?Un,K  
{ _cDF{E+;  
try{ u8zbYd3  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }}{!u0N},V  
int nCount = input.readInt(); 6"j_iB  
nStartPos = new long[nCount]; {.e=qQ%P5)  
nEndPos = new long[nCount]; :q##fG'm/  
for(int i=0;i<nStartPos.length;i++) iP~,n8W  
{ *y[PNqyd  
nStartPos = input.readLong(); wYsZM/lw  
nEndPos = input.readLong(); jMBiaX`
F  
} t6N*6ld2b  
input.close(); 0Rxe~n1o  
} em@EDMvI  
catch(IOException e){e.printStackTrace ();} XdEPbD-  
catch(Exception e){e.printStackTrace ();} Ft{[ae?4  
} zRl~^~sY  
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private void processErrorCode(int nErrorCode) p 5u_1U0  
{ )n7l'}o?+  
System.err.println("Error Code : " + nErrorCode); Tn-C>=tR~%  
} ]bCq=6ZKR  
L7Dh(y=;7  
P%pp )BS  
//停止文件下载 ]J1S#Q5'  
public void siteStop() Hq&"+1F  
{ 3Q}$fQ&S  
bStop = true; PnT)LqEF  
for(int i=0;i<nStartPos.length;i++) `<\}FS`'  
fileSplitterFetch.splitterStop(); f}%D"gz  
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} <{(/E0~V/<  
} pI`?(5iK6|  
//负责部分文件的抓取 }H:F< z*  
**FileSplitterFetch.java D?jk$^p~m#  
*/ UO`;&e-DB  
package NetFox; JD>d\z2QC  
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import java.io.*; |8_JY2 R  
import java.net.*; =?0lA_ 0  
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public class FileSplitterFetch extends Thread { 8Chj w wB  
W~T}@T:EN  
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String sURL; //File URL EC&@I+'8Q  
long nStartPos; //File Snippet Start Position !H][LXB~H  
long nEndPos; //File Snippet End Position
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int nThreadID; //Thread's ID 2Tav;LKX  
boolean bDownOver = false; //Downing is over Myat{OF  
boolean bStop = false; //Stop identical .@ C{3$,VG  
FileAccessI fileAccessI = null; //File Access interface ]36sZ *  
+#@"*yj3  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Q~D`cc|]  
{ +eX)48
 
this.sURL = sURL; @\_x'!R  
this.nStartPos = nStart; A?Qa 4i  
this.nEndPos = nEnd; _#e&t"@GS  
nThreadID = id; FxG7Pk+=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6~:Sgt nU  
} aMARZ)V  
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public void run() Dz=k7zRg"  
{ fJ*:{48  
while(nStartPos < nEndPos && !bStop) h~U02"$  
{ \b'xt  
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try{ 38V3o`f  
URL url = new URL(sURL); /NT[ETMk+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3LR p2(A  
httpConnection.setRequestProperty("User-Agent","NetFox"); =!Vf  
String sProperty = "bytes="+nStartPos+"-"; 1xNVdI  
httpConnection.setRequestProperty("RANGE",sProperty); T`/IO.2  
Utility.log(sProperty); M/D)".;  
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InputStream input = httpConnection.getInputStream(); k@>\LR/v  
//logResponseHead(httpConnection); 1RLY $M  
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$ZPX]2D4B#  
byte[] b = new byte[1024]; AEmNHO@%q  
int nRead; I|oT0y&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &Wp8u#4L  
{ A|#`k{+1-  
nStartPos += fileAccessI.write(b,0,nRead); 3T\l]? z  
//if(nThreadID == 1) JN/UUfj  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :_<_[Y]1  
} T
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:qhpL-ER  
Utility.log("Thread " + nThreadID + " is over!"); +@9gkPQQ-@  
bDownOver = true; {>3\N0e5  
//nPos = fileAccessI.write (b,0,nRead); )'4P.>!!aQ  
} v7  
catch(Exception e){e.printStackTrace ();} 9L0GLmLk1u  
} !9*c8bL D  
} snM Z0W  
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//打印回应的头信息 [,EpN{l  
public void logResponseHead(HttpURLConnection con) }TRAw#h  
{ .D,p@4  
for(int i=1;;i++) =rA~7+}  
{
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String header=con.getHeaderFieldKey(i); V~DMtB7  
if(header!=null) SEwk
u}  
//responseHeaders.put(header,httpConnection.getHeaderField(header));
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Utility.log(header+" : "+con.getHeaderField(header)); F+ <Z<q  
else }uHrto3M  
break; {U]H;~3 ?  
} oeSN9O  
} FLal}80.o:  
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>%p{38  
public void splitterStop() \?>Hu v  
{ 1sE?YJP-  
bStop = true; 0<"k8 k@J  
} )C(>H93  
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} !?f5>Bl  
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/* +h^jC9,m~{  
**FileAccess.java }<@j'Ok}.  
*//文件访问(定位，写) .M,RFC  
package NetFox; uY_SU-v  
import java.io.*; Mwb/jTp  
"q}FPJ^l_N  
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public class FileAccessI implements Serializable{ Y^Nuz/  
Rtb :nJ8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ]A FI\$qB\  
RandomAccessFile oSavedFile; 4p%A8%/q  
long nPos; )m6M9eC  
V^y^ ;0I}[  
u$%t)2+$4  
public FileAccessI() throws IOException T +5X0 Nv  
{ A,su;Qh  
this("",0); NC&DFJo  
} (%iRaw7hp  
['z[  
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public FileAccessI(String sName,long nPos) throws IOException 6cqP2!~  
{ FYs)MO  
oSavedFile = new RandomAccessFile(sName,"rw"); !8 &=y  
this.nPos = nPos; gOgps:  
oSavedFile.seek(nPos); EM>}0V  
} 'c\iK
=fl  
&DqE{bBd!  
bo.(zAz  
public synchronized int write(byte[] b,int nStart,int nLen) r&-m
=Kk$  
{ aA7=q=  
int n = -1; '=][J_
 
try{ G!4(BGx&  
oSavedFile.write(b,nStart,nLen); Pxn,Qw*  
n = nLen; AM=z`0so  
} f7Ul(D:j\  
catch(IOException e) "Ci
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{ 0G!]=  
e.printStackTrace (); zByT$P-  
} !lo/xQ<  
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return n; (EPsTox  
} "~TA SX_?  
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} +r3IN){jz  
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/* .`?@%{  
**SiteInfoBean.java Vh>Z,()>>@  
*/ 8Lw B B  
package NetFox; KZ~*Nz+H2  
(sWLhUgRX  
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public class SiteInfoBean { Ov<NsNX]  
}i!J/tJ)b  
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private String sSiteURL; //Site's URL yCCrK@{oo  
private String sFilePath; //Saved File's Path yA47"R  
private String sFileName; //Saved File's Name I%urz!CNE*  
private int nSplitter; //Count of Splited Downloading File SwZA6R&  
+SJd@y@fR  
>:lnt /N3  
public SiteInfoBean() Jmx Ko+-  
{//nSplitter的缺省值为5 S*yjee<@  
//default value of nSplitter is 5 v%Wx4v@%SE  
this("","","",5); ,@5I:X!rR  
} +{
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m.,U:>  
37}D9:#5C  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Y3Q9=u*5  
{ sH\5/'?  
sSiteURL= sURL; J=/5}u_gw  
sFilePath = sPath; :6%Z]tt  
sFileName = sName; %D *OO{  
this.nSplitter = nSpiltter; &r:7g%{n  
43=,yz2Ef  
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} 8_N]e'WUh  
2WG>, 4W2  
XVU2T5s}  
public String getSSiteURL() 3po:xMY  
{ 0Lb4'25.  
return sSiteURL; f
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} 5 (A5Y-B  
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public void setSSiteURL(String value) ~y7jCcd`  
{ $
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sSiteURL = value; @e{^`\l=<  
} Dl}$pN  
{AQ=<RDRF  
jVq(?Gc  
public String getSFilePath() %Rsp;1Z  
{ #Skv(IL  
return sFilePath; =z8f]/k*>  
} !kC*g  
Od|$Y+@6  
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public void setSFilePath(String value) .aflsUD  
{ KZeQ47|  
sFilePath = value; $cZUM}@  
} jq!tT%o*B  
N 8-oY$*  
)(@Hd  
public String getSFileName() bwl|0"f+`  
{ dh $bfAb  
return sFileName; |n] d34E  
} y8DhOlewQ  
> %KuNy{  
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public void setSFileName(String value) znHnVYll(  
{ iya"ky~H  
sFileName = value; }C|dyyr  
} \W`w` o  
5+wAzVA  
$r3i2N-I  
public int getNSplitter() uDZT_c'Y  
{ LupkrxV  
return nSplitter; 0c#/hFn  
} 5v6Eii:  
p*P
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1u9LdkhnY  
public void setNSplitter(int nCount) 4f;HQ-Iv  
{ -uy`!A  
nSplitter = nCount; k|!EDze43?  
} *H|M;G  
} 9tqF8pb7v  
&sd}ulEg`  
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/* f@c`8L@g  
**Utility.java &kpwo )  
*/ #KiRfx4G  
package NetFox; 0MdDXG-7  
1&U>,;]*
 
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public class Utility { UMcgdJB  
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public Utility() :]1TGfS  
{ 
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"l*`>5Nn9  
(/j); oSK  
} o+$7'+y1n-  
b 'pOJ
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//线程睡眠 = MOj|NR [  
public static void sleep(int nSecond) (#E.`e1#6  
{  ({=gw9f  
try{ 5EfS^MRf\n  
Thread.sleep(nSecond); ^!by3Elqqk  
} BV[5}  
catch(Exception e) #gcF"L||  
{ 1OF& *  
e.printStackTrace (); aqc?pqM  
} UQI]>#_/v  
} Os1>kwC  
1cD! :[  
//日志 vt9)pMs  
public static void log(String sMsg) \0f{S40  
{ <fFTY130:  
System.err.println(sMsg); f|tjsZxQ  
} B,=H
@[Fj  
W!>.$4Q9  
HI11Jl}{  
public static void log(int sMsg) D'Y-6W3  
{ AQiwugs  
System.err.println(sMsg); ]3l
9:|  
} N/K.%<h  
} x" L20}  
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AQ[GO6$,%H  
/* A"rf
Z`  
**TestMethod.java E`uY1B[c  
*/ z\%Ls   
package NetFox; d*%`!G  
F ;2w1S^  
R'@9]99  
public class TestMethod { AGYc |;  
%s(k_|G+4  
(j3xAA  
public TestMethod() K$E3QVa  
{ ///xx/weblogic60b2_win.exe xe` </  
try{ !*%WuyCgr4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); T"DlT/\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [.uG5%fa  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ='
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fileFetch.start(); Qh'ATo  
} m~-K[+ya`D  
catch(Exception e){e.printStackTrace ();} +w{*Xk)4  
5?F__Hx*2  
PC-"gi=h  
} ~2QR{; XQ  
!~rY1T~  
P<a)25be/  
public static void main(String[] args) UZJCvfi  
{ J2xw) +  
new TestMethod(); V#S9H!hm$  
} e3nYbWBy]  
} h1B16)  
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