http断点续传简单实现（java)

/* =^O84Cp 6  
**SiteFileFetch.java ^=}~  
*/ \snbU'lfP  
package NetFox; N"2P&Ho]  
import java.io.*; kS8srT /H  
import java.net.*; $Vlfg51ob  
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public class SiteFileFetch extends Thread { cJGA5m/{I  
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SiteInfoBean siteInfoBean = null; //文件信息Bean h,\^Sb5AP  
long[] nStartPos; //开始位置 \#lh b  
long[] nEndPos; //结束位置 xEOR\(Z^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 acRPKTs H  
long nFileLength; //文件长度 ?k<wI)JR  
boolean bFirst = true; //是否第一次取文件 f]0kG  
boolean bStop = false; //停止标志 .KIAeCvl\  
File tmpFile; //文件下载的临时信息 !3-mPG< ]  
DataOutputStream output; //输出到文件的输出流 J3}^\k=p"  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） t
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public SiteFileFetch(SiteInfoBean bean) throws IOException u> %r(  
{ aGr(djD  
siteInfoBean = bean; ~bWqoJ;Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); +7|Oy3s  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); X6N^<Z$  
if(tmpFile.exists ()) MVe5j+8  
{ FJ!
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bFirst = false; VVYQIR]!yk  
read_nPos(); +)qPUKb?  
} i6h:%n]Io  
else M#=woj&[  
{ ahhVl=9/ao  
nStartPos = new long[bean.getNSplitter()]; ) Z0  
nEndPos = new long[bean.getNSplitter()]; <T+Pw7X   
} \$yI'q  
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9 /t}S6b{  
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} nR!qolh  
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public void run() Q^Y>T&Q  
{ h}g _;k5R  
//获得文件长度 _0oZgt)  
//分割文件 $*G]6s
  
//实例FileSplitterFetch {>5z~OV  
//启动FileSplitterFetch线程 $kZ,uvKN  
//等待子线程返回 R 7xV{o  
try{ S;Lqx5Cd  
if(bFirst) kFw3'OZ,  
{ "P&|e|7  
nFileLength = getFileSize(); IE|x+RBD  
if(nFileLength == -1) Gvtd )9^<  
{ mu=u!by.E  
System.err.println("File Length is not known!"); j8hb  
} HqcXP2  
else if(nFileLength == -2) gG*O&gQY  
{ :1hp_XfJb  
System.err.println("File is not access!"); DS=kSkW^&5  
} ky#<\
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else FK }x*d  
{ QbV)+7II=  
for(int i=0;i<nStartPos.length;i++) j<"0ym)A  
{ qVZ=:D{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); F
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} `axNeqM  
for(int i=0;i<nEndPos.length-1;i++) 'gI58#v  
{ >^+Q`"SN  
nEndPos = nStartPos[i+1]; 3|/ ;`KfQ  
} 1YAy\F~`.  
nEndPos[nEndPos.length-1] = nFileLength; !yojZG MB  
} 0=t_a]+  
} 5NJ@mm{0  
yc_(L-'n  
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//启动子线程 X H{5E4P  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; s ~(qO|d  
for(int i=0;i<nStartPos.length;i++) {Y`0}  
{ _^#PV}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), e%wbUr]c2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), R?Iv<(I  
nStartPos,nEndPos,i); S4~^HvMG[Y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Wq&TbWR  
fileSplitterFetch.start(); ]L}<Y9)t  
}
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |n01T_Z)P  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); V0wK.^]+}/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l*B;/ >nR  
nEndPos = " + nFileLength);  by>,h4  
// fileSplitterFetch[nPos.length-1].start(); m4>v S  
OWtN=Gk  
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//等待子线程结束 ~4XJ" d3L  
//int count = 0; FRs5 Pb1  
//是否结束while循环 "%,zB_ng\<  
boolean breakWhile = false; n;v8Vc'  
8QFY:.h&  
YH
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while(!bStop) sAnStS=>  
{ tnRq?  
write_nPos(); mfeyR  
Utility.sleep(500); w`F}3zm  
breakWhile = true; Qnr' KbK  
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for(int i=0;i<nStartPos.length;i++) u^!-Z)W  
{
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if(!fileSplitterFetch.bDownOver) dYfVox;  
{ ]7h&ZF  
breakWhile = false; z4UeUVfZ}  
break; Pg*ZQE[ME8  
} AD*+?%hj  
} sx`C<c~u  
if(breakWhile) WXO@oZ!  
break; zcIZJVYA  
mR8&9]g&  
# ?}WQP!  
//count++; 3o"~_l$z  
//if(count>4) ~[k2(  
// siteStop(); IF5+&O  
} @B+  
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System.err.println("文件下载结束！"); |M9x&(H;Hw  
} :t\PYDp1  
catch(Exception e){e.printStackTrace ();} ]C5JP~#z  
} O23f\pm&  
I#uJdV|x  
Ji%T|KR_  
//获得文件长度 &qr
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public long getFileSize() ~q-|cl<  
{ W9a H]9b  
int nFileLength = -1; &W".fRH_O  
try{ ~[ve?51  
URL url = new URL(siteInfoBean.getSSiteURL()); cJi5\<b  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); //V?rs  
httpConnection.setRequestProperty("User-Agent","NetFox"); {U-VInu  
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int responseCode=httpConnection.getResponseCode(); hj0uv6t.c  
if(responseCode>=400) "xnek8F  
{ .i[Tp6'%,  
processErrorCode(responseCode); L7a+ #mGE  
return -2; //-2 represent access is error s{$c8  
} P9X/yZ42  
i1|-  
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String sHeader; N @]*E  
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for(int i=1;;i++) l3l[jDa,2  
{ Ao?H.=#y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %<I0-o  
//Utility.log(in.readLine()); <t]i'D(K  
sHeader=httpConnection.getHeaderFieldKey(i); r&Za*TD^  
if(sHeader!=null) b>
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{ w7w$z_P  
if(sHeader.equals("Content-Length")) <J
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{ s)xfTr_$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); BD,~M*%z  
break; NTgk0cq  
} Y @pkfH  
} D
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else T5W r;a  
break; cs~ }k7><  
} R
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} %oC]Rpdu  
catch(IOException e){e.printStackTrace ();} 4?72TBl]  
catch(Exception e){e.printStackTrace ();} M*aE)D '  
9OXrz}8C  
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Utility.log(nFileLength); 'fawpU|h  
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return nFileLength; }6m5MH$7q  
} P#rwYPww\  
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od?Q&'A  
//保存下载信息（文件指针位置） *w> /vu  
private void write_nPos() N|7<*\o  
{ J>XaQfzwU  
try{ /KlA7MH6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *.voN[$~  
output.writeInt(nStartPos.length); G}D?+MWY  
for(int i=0;i<nStartPos.length;i++) dpE\eXoa,  
{ >G/>:wwSP.  
// output.writeLong(nPos); O&d
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output.writeLong(fileSplitterFetch.nStartPos); XD%?'uUQ_  
output.writeLong(fileSplitterFetch.nEndPos); l_^>spF  
} 7fnKe2MM  
output.close(); K2:r
7f  
} ]p+t>'s  
catch(IOException e){e.printStackTrace ();} ^b>E_u  
catch(Exception e){e.printStackTrace ();} ?uQ|?rk  
} VJHHC.Kz  
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//读取保存的下载信息（文件指针位置） #8nF8J<4  
private void read_nPos() T7cT4PAW  
{ Ldir'FW  
try{ Z4hP  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); b39;Sv|#  
int nCount = input.readInt(); fp12-Hk ~  
nStartPos = new long[nCount]; CAcnH  
nEndPos = new long[nCount]; R&PQ[Xc  
for(int i=0;i<nStartPos.length;i++) Ds L]o  
{ :
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nStartPos = input.readLong(); PMXnupt  
nEndPos = input.readLong(); uz'beE  
} FopD/D{  
input.close(); 5:n&G[Md  
} mpr["C"l  
catch(IOException e){e.printStackTrace ();} Z][?'^`^!  
catch(Exception e){e.printStackTrace ();} _;LH
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} &\!-d%||)  
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private void processErrorCode(int nErrorCode) ]*zF#Voc  
{ V!FzVl=G  
System.err.println("Error Code : " + nErrorCode); `4;<\VYCr  
} QW6k!ms$  
GIZNHG  
~xvQ?c?-  
//停止文件下载 }$AC0  
public void siteStop() *bv Iqa  
{ rM>&!?y+  
bStop = true; tQ2*kE  
for(int i=0;i<nStartPos.length;i++) hb? |fi  
fileSplitterFetch.splitterStop(); @}fnR(fS  
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} VT'$lB%IK  
} WQ"ZQ  
//负责部分文件的抓取 zh50
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**FileSplitterFetch.java o_\b{<^I  
*/ A]=?fyPh{'  
package NetFox; MgtyO3GUAD  
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import java.io.*; 09x
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import java.net.*; w_|WberU  
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public class FileSplitterFetch extends Thread { oMMU5sm  
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String sURL; //File URL WtlIrdc  
long nStartPos; //File Snippet Start Position G.oaDGy  
long nEndPos; //File Snippet End Position AHZ6  
int nThreadID; //Thread's ID KE5f`h  
boolean bDownOver = false; //Downing is over |AWu0h\keO  
boolean bStop = false; //Stop identical Ke'bH  
FileAccessI fileAccessI = null; //File Access interface d3n TJX  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1/#N{rZ  
{ DI$zyj~3  
this.sURL = sURL; c\;}ov+  
this.nStartPos = nStart; 9qqEr
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this.nEndPos = nEnd; IndNR:"g  
nThreadID = id; _$=xa6YA  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "[#jq5> :  
} z1V0WDVm  
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public void run() I1}{7-_t  
{ ::M/s#-@  
while(nStartPos < nEndPos && !bStop)  |u$AzI  
{ 7q67_u?@  
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try{ `*N0 Lbl]  
URL url = new URL(sURL); kYR&t}jlCg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~F' $p  
httpConnection.setRequestProperty("User-Agent","NetFox"); }wv$ #H[  
String sProperty = "bytes="+nStartPos+"-"; {) .=G  
httpConnection.setRequestProperty("RANGE",sProperty); RcHyePuF)R  
Utility.log(sProperty); 1C|j<w=i  
3cfkJ|fuwe  
8KAyif@1::  
InputStream input = httpConnection.getInputStream(); m' aakq  
//logResponseHead(httpConnection); $*@mxwMQ}  
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byte[] b = new byte[1024]; :V_$?
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int nRead; YTGup]d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4wBCs0NIm  
{ =1esUO[nx  
nStartPos += fileAccessI.write(b,0,nRead); Q5jP`<zWU  
//if(nThreadID == 1) h]zx7zt-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); TvQAy/Y0  
} 6dinC <[}  
fIBLJ53  
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Utility.log("Thread " + nThreadID + " is over!"); 7'&Xg_  
bDownOver = true; Ne#nSx5,  
//nPos = fileAccessI.write (b,0,nRead); Ia(A&Za  
} 2'x_zMV  
catch(Exception e){e.printStackTrace ();} z.jGVF4  
} opIcSm&  
} 95H`-A  
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//打印回应的头信息 -bj1y2)n  
public void logResponseHead(HttpURLConnection con) / _cOg? o  
{ 8F@6^9C  
for(int i=1;;i++) 2`Pk@,:_  
{ k?";$C}#  
String header=con.getHeaderFieldKey(i); w6cPd'  
if(header!=null) '@:;oe@]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); f/=0  
Utility.log(header+" : "+con.getHeaderField(header)); Bf-&[ 5N}  
else Q2NS>[  
break; 4,aBNuxWd  
} #h&?wE>  
} vAVoFL  

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public void splitterStop() b#]in0MT?@  
{ KS|$_-7u  
bStop = true; 9u)h$VC  
} -\I0*L'$|\  
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:4Y|%7[  
} ML'R[~|  
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S\ li<xl  
/* ooD/QZUE  
**FileAccess.java xp39TiXJ*  
*//文件访问(定位，写) dB/Epc&   
package NetFox; NT-du$!u  
import java.io.*; r>G$u  
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/!
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public class FileAccessI implements Serializable{ "RG.vo7b  
LCdc7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `"bm Hs7  
RandomAccessFile oSavedFile; rLVAI#ci=  
long nPos; Im Tq`  
JhD8.@} b~  
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public FileAccessI() throws IOException ZWr\v!4  
{ JLeV@NO  
this("",0); !^N/n5eoz  
} jK{CjfCNz  
({8Q=Gh  
$Qm;F% >  
public FileAccessI(String sName,long nPos) throws IOException &,#VhT![  
{ g$:2c7uL  
oSavedFile = new RandomAccessFile(sName,"rw"); -Rf|p(SJ,E  
this.nPos = nPos; bc 0|tJc  
oSavedFile.seek(nPos); kg-%:;y.  
} SC!IQ80H#D  
!.F\v.  
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public synchronized int write(byte[] b,int nStart,int nLen) ~
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{ fZGKVxo"  
int n = -1; * T~sR'K+|  
try{ CsE|pXVG  
oSavedFile.write(b,nStart,nLen); vWgh?h/ot  
n = nLen; Rc6Rk!^  
} D@3|n
S  
catch(IOException e) q2SkkY$_]y  
{ +wio:==  
e.printStackTrace (); 0m@S+$v  
} ~ PPGU1  
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return n; >,9t<p=Q  
} `C=p7%  
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} T xN5K`q  
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/* ]-q:Z4rb  
**SiteInfoBean.java Z-~^)lo  
*/ aRV!0?fS  
package NetFox; \k* ]w_m-  
.)o5o7H  
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public class SiteInfoBean { sO*6F`eiZ  
tF'67,~W  
j^k{~]+_^]  
private String sSiteURL; //Site's URL mEqV&M1;7l  
private String sFilePath; //Saved File's Path I?:V EN:  
private String sFileName; //Saved File's Name FJD*A`a  
private int nSplitter; //Count of Splited Downloading File l%)XPb2$J  
d*G$qUiX  
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public SiteInfoBean() 0q3:"X  
{//nSplitter的缺省值为5 B[*i}k%i  
//default value of nSplitter is 5 7Jqp2\  
this("","","",5); }%}eyLm(  
} (thzWr6;  
b!N`@m=  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) d,>l;
l  
{ ^=@%@mR/[C  
sSiteURL= sURL; 
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sFilePath = sPath; '3xSzsDn  
sFileName = sName; 1|`9Hp6  
this.nSplitter = nSpiltter; %AJdtJ@0H  
i7p3GBXh[  
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} O 8fh'
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public String getSSiteURL() abF_i#  
{ L2:C6Sc  
return sSiteURL; %URyGS]*  
} <;Xj4 J  
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public void setSSiteURL(String value) f&,.h"b
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{ [m4<j  
sSiteURL = value; ':fVb3A[*d  
}  [g/g(RL  
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public String getSFilePath() J0x)m2  
{ Lh0<A%  
return sFilePath; 5=$D~>-#  
} /
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public void setSFilePath(String value) p'R}z|d)  
{ 6Y=$7%z  
sFilePath = value; y
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} y@(U6ZOyx  
+yYz;, \  
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public String getSFileName() s5[ Cr"q7B  
{ AKHi$Bk  
return sFileName; s*Fmu7o43  
} %8v?dB;>x`  
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/1^%32c  
public void setSFileName(String value) [k.<x'#  
{ v3[ 2!UXq  
sFileName = value; 7N:,F9V<  
} #-{4 Jx  
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t
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public int getNSplitter() )UxF lp;\  
{ oZIoY*7IrQ  
return nSplitter; 9
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} .qHgQ_%  
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q  
public void setNSplitter(int nCount) 8'f:7KF  
{ %II |;<  
nSplitter = nCount; l
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} /6f$%:q  
} {!<zk+h$  
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}(  
/* h-6kf:XP%  
**Utility.java ;Neld #%J  
*/ PsTwJLY   
package NetFox; qEywExdiu  
J0{0B=d;  
l.&6|   
public class Utility { 0uj3kr?cv  
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public Utility() k6$.pCH6  
{ v_b%2;<1  
OpiN,>;  
**oN/5  
} "EA%!P:d,  
a*o=,!  
//线程睡眠 UD.$C  
public static void sleep(int nSecond) b2ZKhS8  
{ p-;*K(#X  
try{ "zYlddh  
Thread.sleep(nSecond); %SIbpk%  
} WJl&Vyl2FL  
catch(Exception e) ZX'/[wAN)  
{ 1YQ|KJ*K  
e.printStackTrace (); >8QLo8)3C  
} t.3b\RV[  
} k|&@xEbS  
uNLA/hL+n  
//日志 0b4QcfB1[  
public static void log(String sMsg) X\uN:;?#W{  
{ _O)~<Sk-*z  
System.err.println(sMsg); QKe=/;  
} qL]!/}  
2x t 8F  
zsWYV n]  
public static void log(int sMsg) \|Us/_h  
{ CGPPo;RjK  
System.err.println(sMsg); Z?dz@d%C  
} 7hQ
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} kWF, *@.B  
T
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J](AJkGzK  
/* 3g)pLW  
**TestMethod.java 7mt;qn?n  
*/ #5=Yg5   
package NetFox; V)C4 sG  
 \&"gCv#  
M"1}"ex#  
public class TestMethod { YiB^m  
Q.@9"&)t  
YG$Y4h" @"  
public TestMethod() jq%Qc9y  
{ ///xx/weblogic60b2_win.exe /0@'8f\I  
try{ 0]fzjiaGt  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 3+0$=ef  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); R>yoMk/u  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E&/#Ov  
fileFetch.start(); T5Yu+>3  
} KHI-m9(  
catch(Exception e){e.printStackTrace ();} 4uwI=
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EH=[!iW;  
} X6kCYTJYF  
4Un(}P'  
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public static void main(String[] args) ,eW K~ pa  
{ JN,4#,  
new TestMethod(); ^cn%]X#.  
} Il`35~a  
} =# <!s!  
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