http断点续传简单实现（java)

/* HFo-4"  
**SiteFileFetch.java OQ4c#V?  
*/ Gzt=u"FV  
package NetFox; f+Dn9t  
import java.io.*; w7-
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import java.net.*; XD-^w_  
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public class SiteFileFetch extends Thread { N;HIsOT}t  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %do1i W  
long[] nStartPos; //开始位置 h4fLl3%H  
long[] nEndPos; //结束位置 \k.vN@K#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 LD(C\  
long nFileLength; //文件长度 V/"}ku  
boolean bFirst = true; //是否第一次取文件 TSL9ax4j  
boolean bStop = false; //停止标志 7\/5r.  
File tmpFile; //文件下载的临时信息 znZ7*S >6\  
DataOutputStream output; //输出到文件的输出流 ~# 7wdP  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） UQd6/mD`e  
public SiteFileFetch(SiteInfoBean bean) throws IOException O.k\]'  
{ q]<xMg#nu  
siteInfoBean = bean; 0y%L-:/c|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); N dR ]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); r$nkU4N'  
if(tmpFile.exists ()) h3Fo-]0  
{ FA>1x*;c  
bFirst = false; 6J%iZ  
read_nPos(); u/AT-er;  
} V!|e#}1/  
else SFjU0*B$  
{ ]UNZd/hIL  
nStartPos = new long[bean.getNSplitter()]; Fa3gJ[ZAqf  
nEndPos = new long[bean.getNSplitter()]; aW{L7N%  
} EZ#gp^$  
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} }X$l\pm  
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public void run() Q e1oT)  
{ #Ws53mT  
//获得文件长度 5n:71$6[  
//分割文件 ,EhVSrh)_4  
//实例FileSplitterFetch r(uP!n1+  
//启动FileSplitterFetch线程 (;6s)z  
//等待子线程返回 ,9ml>ji`=  
try{ sms1%%~  
if(bFirst) 8?jxDW a  
{ oL *n>dH  
nFileLength = getFileSize(); a0d ,

 
if(nFileLength == -1) \3{3ly~L  
{ x3p9GAd#  
System.err.println("File Length is not known!"); q#1X[A()  
} aqQ o,5U>  
else if(nFileLength == -2) /jrY%C  
{ Etmo78e  
System.err.println("File is not access!"); %"7WXOv&z  
} n@B{vyy  
else boQ)fV"  
{ rB]W,8~%  
for(int i=0;i<nStartPos.length;i++) R "E<8w  
{ sQk|
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nStartPos = (long)(i*(nFileLength/nStartPos.length)); yMIT(  
} P"4Mm
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for(int i=0;i<nEndPos.length-1;i++) ~8Sqa%F>  
{ mC(u2  
nEndPos = nStartPos[i+1]; hhq$g{+[  
} kMe@+ysL  
nEndPos[nEndPos.length-1] = nFileLength; QTh0SL  
} ;?im(9h"v!  
} #)i&DJ^Y  
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//启动子线程 4%bTj,H#  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I#l;~a<9z  
for(int i=0;i<nStartPos.length;i++) >_#)3K1y8  
{ GAJ~$AiwHH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P06.1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), (Nt[v;BnO  
nStartPos,nEndPos,i); mq`5w)S)\o  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T0L+z/N_m.  
fileSplitterFetch.start(); A#:8X1w  
} 8xo;E=`   
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $,`VUe{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); YeIe\3x!N  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]N\6h(**wy  
nEndPos = " + nFileLength); $
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// fileSplitterFetch[nPos.length-1].start(); cHn;}l!I  
_[$# b]V  
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//等待子线程结束 U2&HSE|2J  
//int count = 0; T#e4":A&x  
//是否结束while循环 pYGYy'%A'  
boolean breakWhile = false; FH -p!4+]  
~j}J<4&OvC  
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while(!bStop) q6)p*}-  
{ s*{mT6s+T  
write_nPos(); }B*,mn2N  
Utility.sleep(500); LY1KQuY  
breakWhile = true; ftW{C1,U7  
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for(int i=0;i<nStartPos.length;i++) (+$ol'i  
{ ;z
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if(!fileSplitterFetch.bDownOver) ):}Fu  
{ w&+\Wo;([b  
breakWhile = false; j/`Up  
break; US]"4=Zm
 
} ;x RjQR
 
} Z]e4pR6!  
if(breakWhile) 9C1
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break; *?b@>_1K  
{*nEKPq(_*  
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//count++; qV?sg  
//if(count>4) 67ZYtA|t  
// siteStop(); Z_jn27AC  
} .='3bQ(UZ4  
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System.err.println("文件下载结束！"); P[1m0!,B  
} 8+L7E-  
catch(Exception e){e.printStackTrace ();} J2Y 3er  
} xK=J.>h3  
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//获得文件长度 rkP4<E-M  
public long getFileSize() q'fPNQ

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{ Kd TE{].d  
int nFileLength = -1; S].Ft/+H  
try{ &Ky3Jb<:Gt  
URL url = new URL(siteInfoBean.getSSiteURL()); be_C>v  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); CElPU`J,\[  
httpConnection.setRequestProperty("User-Agent","NetFox"); /W?z0tk`  
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int responseCode=httpConnection.getResponseCode(); bA0uGLc  
if(responseCode>=400) xan/ay>  
{ Yo@m50s$  
processErrorCode(responseCode); ]zy~@,\  
return -2; //-2 represent access is error U"/yB8!W  
} widI s[ )  
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String sHeader; A&;EV#]ge  
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for(int i=1;;i++) S]5VEn;pV  
{ N!.kq4$.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); rS
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//Utility.log(in.readLine()); L;4[ k;5  
sHeader=httpConnection.getHeaderFieldKey(i); @\S]]oLn  
if(sHeader!=null) 1Q0%7zRirI  
{ ;7wwY$PBH  
if(sHeader.equals("Content-Length")) $:PF9pY(  
{ nq),VPJi  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9PUa?Bc`=  
break; v hR twi  
} fuQ4rt[i  
} (q~R5)D  
else X9DM^tt  
break; ?'TA!MR  
} 3^j~~"2,w  
} 3"f)*w7d  
catch(IOException e){e.printStackTrace ();} V^9$t/c&  
catch(Exception e){e.printStackTrace ();} 'MSEki67  
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Utility.log(nFileLength); d?Ia#K93G  
.jLMl*6%:  
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return nFileLength; D$Kz9GVZq  
} y*y`t6D  
x:=0.l#  
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//保存下载信息（文件指针位置） AB/,S  
private void write_nPos() FGV}5L  
{ 782[yLyv  
try{ s$
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output = new DataOutputStream(new FileOutputStream(tmpFile)); HKq2Js  
output.writeInt(nStartPos.length); 97['VOh0  
for(int i=0;i<nStartPos.length;i++) 6#OL ;Y]_  
{ k'6<jEbk  
// output.writeLong(nPos); YJ&lB&xH  
output.writeLong(fileSplitterFetch.nStartPos); 2]?w~qjWm  
output.writeLong(fileSplitterFetch.nEndPos); W?SP .-I  
} HVtr,jg  
output.close(); iMP*]K-O  
} |LXrGyk^  
catch(IOException e){e.printStackTrace ();} Ufm(2`FQ  
catch(Exception e){e.printStackTrace ();} 7KvXTrN!9  
} CsJ)Z%4_  
-d$8WSI8  
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//读取保存的下载信息（文件指针位置） e{^:/WcYB  
private void read_nPos() P-/XYZ]`  
{ stf,<W  
try{ +a7EsR  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); U:s}/to  
int nCount = input.readInt(); 5KL9$J9k  
nStartPos = new long[nCount]; <^H1)=tlF  
nEndPos = new long[nCount]; BfD,z  
for(int i=0;i<nStartPos.length;i++) [[";1l  
{ OqEg{o5 a&  
nStartPos = input.readLong(); < fojX\}3  
nEndPos = input.readLong(); Fw(b1d>E  
} ZXF
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input.close(); ~rVKQ-+4&  
} &4w\6IR  
catch(IOException e){e.printStackTrace ();} #i`A4D  
catch(Exception e){e.printStackTrace ();} d,GtH)(s  
} GInZ53cQ  
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private void processErrorCode(int nErrorCode) hqhu^.}]  
{ f:x9Y{Y  
System.err.println("Error Code : " + nErrorCode); T% /xti5$!  
} I_"Hgx<  
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WHpUjyBP  
//停止文件下载 iBGS
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public void siteStop() 3p?<iVE  
{ Sleu#]-  
bStop = true; `:-@E2  
for(int i=0;i<nStartPos.length;i++) 3/A!_Uc(  
fileSplitterFetch.splitterStop(); 1Pw(.8P  
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} 7yqSt)/U  
} rL!_&|  
//负责部分文件的抓取 78^UgO/  
**FileSplitterFetch.java % K9;
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*/ \-$bo=s.  
package NetFox; 4Vb}i[</  
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import java.io.*; /ZIJ<#o[
 
import java.net.*; Q`
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.BYKdxa  
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public class FileSplitterFetch extends Thread { Xh7~MU~X  
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String sURL; //File URL uv~qK:Nw(  
long nStartPos; //File Snippet Start Position /el["l
 
long nEndPos; //File Snippet End Position 4."o.:8x  
int nThreadID; //Thread's ID uI[-P}bSc&  
boolean bDownOver = false; //Downing is over }rj C_q  
boolean bStop = false; //Stop identical |d
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FileAccessI fileAccessI = null; //File Access interface @dWS*@  
\GbHS*\+  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1Rb XM n  
{ !yV,|)y5F  
this.sURL = sURL; ]]h:#A2  
this.nStartPos = nStart; Y^94iOk%T  
this.nEndPos = nEnd; ?'ez.a}  
nThreadID = id; }ZM*[j  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 EL 8N[]RF  
} `\RX~ $^  
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public void run() &z xBi"  
{ &0th1-OP_  
while(nStartPos < nEndPos && !bStop) 4mM2C`I  
{  s>*Q  
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try{ r:WgjjA%  
URL url = new URL(sURL); R[>;_}5">  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -hU>1ux&V  
httpConnection.setRequestProperty("User-Agent","NetFox"); {l
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String sProperty = "bytes="+nStartPos+"-"; c
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httpConnection.setRequestProperty("RANGE",sProperty); ]9KQP-p'  
Utility.log(sProperty); cAKoPU>U  
/BjGAa(  
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InputStream input = httpConnection.getInputStream(); *Sz{DE1U  
//logResponseHead(httpConnection); @ (u?=x;  
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byte[] b = new byte[1024]; t6h`WAZV  
int nRead; %!HnGwv-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) aCH:#|B  
{ "`W1yk5x  
nStartPos += fileAccessI.write(b,0,nRead); ${I@YSU  
//if(nThreadID == 1) RaM#@D7  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jL7MmR#y5"  
} S$lmEJ_  
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Utility.log("Thread " + nThreadID + " is over!"); ExOB P  
bDownOver = true; ]"7DV3_  
//nPos = fileAccessI.write (b,0,nRead); u7Y'3x,`  
} Io4:$w  
catch(Exception e){e.printStackTrace ();} ?lET4
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} }x#P<d(  
}  wc+N  
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49J+&G?)j  
//打印回应的头信息 1{Alj27  
public void logResponseHead(HttpURLConnection con) 4_m /_Z0x  
{ ]|$$:e^U9  
for(int i=1;;i++) \_I)loPc8  
{ z?t(+^  
String header=con.getHeaderFieldKey(i); O[hbu![  
if(header!=null) @DQ"vFj6<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !k>H e*M}P  
Utility.log(header+" : "+con.getHeaderField(header)); Mly z><  
else J?Ep Nie  
break; MVeQ5c(  
} J6["j  
} wx"6",M  
,^+R%7mv  
@Y&9S)xcE  
public void splitterStop() pv m'pu78  
{ P15*VPy  
bStop = true; %oCjZ"ke  
} J_wz'eIb0  
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} zIQc#F6\5  
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/* [A..<[  
**FileAccess.java |phWK
^  
*//文件访问(定位，写) N;ecT@Ug  
package NetFox; <<2b2?aS`  
import java.io.*; {!g.255+  
V\M!]Nnxr  
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public class FileAccessI implements Serializable{ *r?51
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+ $a:X  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Obc3^pV&  
RandomAccessFile oSavedFile; Ae_ E;
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long nPos; ;gW|qb+#)j  
{O&liU4  
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public FileAccessI() throws IOException +81+4{*  
{ g/X=#!  
this("",0);   [aS)<^  
} U)/Ul>dY
 
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public FileAccessI(String sName,long nPos) throws IOException "xc*A&Sg  
{ gAUQQ  
oSavedFile = new RandomAccessFile(sName,"rw"); e"adkV  
this.nPos = nPos; Z8dN0AqZ  
oSavedFile.seek(nPos); ]>4Qs  
} (Nlm
4*{h  
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public synchronized int write(byte[] b,int nStart,int nLen) &|{,4V0%A  
{ c+)|o!d  
int n = -1; .sR&9FH  
try{ D_ZBx+/_?  
oSavedFile.write(b,nStart,nLen); S,tVOxs^  
n = nLen; 8m[L]6F(-z  
} s=~7m
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catch(IOException e) MJ"Mn^:/  
{ *,[=}v1  
e.printStackTrace (); "!/_h >  
} re7\nZ<\|  
iM/0Yp-v'>  
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return n; >(6\ C  
} rnhf(K.{3  
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} kt3#_d^El  
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/* ^oB1 &G  
**SiteInfoBean.java 1&pP}v ?  
*/ |M/ \'pOe  
package NetFox; y{?jr$js<  
FuiW\=^  
{uM{5GSL  
public class SiteInfoBean { ;_\  
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%+!9  
private String sSiteURL; //Site's URL e&4wwP"`<  
private String sFilePath; //Saved File's Path Qn3
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private String sFileName; //Saved File's Name ;,})VoC\!  
private int nSplitter; //Count of Splited Downloading File %dU'$)  
ZznWs+  
7%}3Ghc%  
public SiteInfoBean() DJ[#H  
{//nSplitter的缺省值为5 f
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//default value of nSplitter is 5 +;iesULXn  
this("","","",5); :(p rx   
} <({eOh5N  
{]Iu">*
 
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _w
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{ 5a_!&  
sSiteURL= sURL; l<:E+lU  
sFilePath = sPath; JI,hy <3l0  
sFileName = sName; !X <n:J  
this.nSplitter = nSpiltter; kpw4Mq@  
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} Aq]'.J=4  
#*M$,ig  
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public String getSSiteURL() 4KSN;G  
{ FH21mwV  
return sSiteURL; J<*Mk  
} g):jZU]b  
vm^# aoDB  
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public void setSSiteURL(String value) .mrRv8>$  
{ "wC5hj]  
sSiteURL = value;
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} *dTf(J  
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public String getSFilePath() @N{Ht)1r  
{ |+~2sbM  
return sFilePath; q;PzB4#  
} 3D dG$@  
(3r,PS@Qq@  
:|Nbk58  
public void setSFilePath(String value) >t}D5ah  
{ 4:PP[2?  
sFilePath = value; 3'e 4{  
} <!(n5y_  
CHw_?#h  
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public String getSFileName() #p`7gFl  
{ =e/4Gs0*  
return sFileName; 0U*"OSpF  
} PQ1NQy8  
bK1`a{  
\bSHBTK  
public void setSFileName(String value) V=MZOj6  
{ =I}V PxhE7  
sFileName = value; h*Tiv^a  
} ]qHO{b4k  
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public int getNSplitter() pdiZ"pe  
{ "Oko|3  
return nSplitter; [E7@W[xr  
} *~^^A9C8  
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public void setNSplitter(int nCount) 97dI4t<  
{ YDD]n*&  
nSplitter = nCount; ADz|Y~V!  
} +[[gU;U"v  
} --FtFo  
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/* GTNTx5H  
**Utility.java OR8o%AxL7  
*/ M?u)H&kEl  
package NetFox; Sxu v}y\  
S]g)^f'a65  
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public class Utility { r=aQS5  
q~_jF$9SX  
dtl<  
public Utility() ,jcp"-5#j  
{ ttVSgKAsm  
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} hDMp^^$  
=o
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//线程睡眠 K_3ZJ  
public static void sleep(int nSecond) 4]KceE  
{ .&.CbE8K[  
try{ >E=a~ O  
Thread.sleep(nSecond); O8o18m8UH  
} &W!@3O{~.  
catch(Exception e) a<.@+sj{  
{ EtGr&\,  
e.printStackTrace (); .r'.5RI A  
} \0*LfVr;P  
} a$:N9&P  
V= PoQ9d  
//日志 ^]gl#&"D  
public static void log(String sMsg) {'kL]qLg  
{ pBkPn+@  
System.err.println(sMsg); '~J6mojE  
} 3)\qts5  
_4Pi>  
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public static void log(int sMsg) {!h[@f4  
{ 3om-,gfZ  
System.err.println(sMsg); .R5z>:A  
} |-D.  
} 0fU>L^P_?  
S
5TT  
e?WR={  
/* u*`GIRfWT  
**TestMethod.java 9t1_"{'N1  
*/ 74#@F{w  
package NetFox; wf1DvsJQl  
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^XVa!s,d  
public class TestMethod { $*R9LPpk+  
UxtZBNn8  
#
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public TestMethod() yl%F<5  
{ ///xx/weblogic60b2_win.exe DmsloPB?_  
try{ qW^l2Jff  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &ii =$4"R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ^pa).B.`T  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _Hk`e}}  
fileFetch.start(); yI<'J^1C[  
} I|H mbTXa  
catch(Exception e){e.printStackTrace ();} i,T{SV  
"o^zOU  
[~wcHE  
} dM$S|,H  
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QNFrkel  
public static void main(String[] args) VuW19-G  
{ ~Y[1Me  
new TestMethod(); QCw<* Id+  
} WAbhBA  
} U"]i.J1  
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