http断点续传简单实现（java)

/* #4<Rs|K  
**SiteFileFetch.java d;10[8:5=  
*/ }vLK-Vv  
package NetFox; 3d@$iAw1<  
import java.io.*; O*7Gl G  
import java.net.*; /_G^d1T1?L  
,
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public class SiteFileFetch extends Thread { OAiip,  
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SiteInfoBean siteInfoBean = null; //文件信息Bean X3j<HQcK  
long[] nStartPos; //开始位置 j3`"9bY  
long[] nEndPos; //结束位置 1"Z61gXrz  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 gM<*(=x'  
long nFileLength; //文件长度 aZMMcd  
boolean bFirst = true; //是否第一次取文件 p;VHg  
boolean bStop = false; //停止标志 L3g}Z1<!$  
File tmpFile; //文件下载的临时信息 Tv{X$`%  
DataOutputStream output; //输出到文件的输出流 O1_dA%m  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ~ST7@-D0  
public SiteFileFetch(SiteInfoBean bean) throws IOException >b.wk3g@>  
{ 5-ju5z?=  
siteInfoBean = bean; c_xo6+:l  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 1$g]&'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _g(4-\  
if(tmpFile.exists ()) &_EjP hZ  
{ T]%:+_,  
bFirst = false; phA^ kdW  
read_nPos(); $m;rOKVU  
} pU|SUM  
else l}$Pv?T,2  
{ Q'~2,%3<  
nStartPos = new long[bean.getNSplitter()]; Ox` +Z0)a  
nEndPos = new long[bean.getNSplitter()]; n"
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} z5G$'  
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} V@
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public void run() 3UBg"1IC  
{
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//获得文件长度 : _>/Yd7-&  
//分割文件 kR0d]"dr  
//实例FileSplitterFetch l 6;}nG  
//启动FileSplitterFetch线程 ;nPjyu'g  
//等待子线程返回 =2z9Aq{  
try{ ?{"_9g9  
if(bFirst) il \q{Y o  
{ :Q\{LBc  
nFileLength = getFileSize(); rN'')n/F  
if(nFileLength == -1) xJ|3}o:,  
{ Er6'Ig|U  
System.err.println("File Length is not known!"); 8yH*  
}  ?vgHu  
else if(nFileLength == -2) SV4a_m?  
{ luyU!  
System.err.println("File is not access!"); 6Y|jK<n?H  
} ",\,lqV  
else APgP*,  
{ "]dNN{Wka  
for(int i=0;i<nStartPos.length;i++) eJB !|  
{ M8 E8r  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?2b*FQe  
} HY,+;tf2r  
for(int i=0;i<nEndPos.length-1;i++) Q-X<zn  
{ S1<mO-  
nEndPos = nStartPos[i+1]; 94umk*ib  
} +@Oo)#V|.  
nEndPos[nEndPos.length-1] = nFileLength; fXPD^}?Ux4  
} a_UVb'z  
} k:Iz>3O3]  
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//启动子线程 \#.@*?fk  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $ePBw~yu  
for(int i=0;i<nStartPos.length;i++) I$o^F/RH  
{ H}OOkzwrA  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Gu-*@C:^&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0k?ph$  
nStartPos,nEndPos,i); QPf#y7_@u  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vpy_piG|  
fileSplitterFetch.start(); gxX0$\8o7  
} p:9)}y  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), w !N;Y0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Xj/U~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", wL'tGAv  
nEndPos = " + nFileLength); q][
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// fileSplitterFetch[nPos.length-1].start(); FF"6~  
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//等待子线程结束 AHq;6cG  
//int count = 0; paUlp7x  
//是否结束while循环 { jnQoxN  
boolean breakWhile = false; *^XfEO  
 q$$:<*Uy  
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while(!bStop) 5} 9}4e  
{ X]J]7\4tF\  
write_nPos(); G:f\wK[  
Utility.sleep(500); "#H@d+u  
breakWhile = true; (o/HLmr@Y  
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for(int i=0;i<nStartPos.length;i++) m@hmu}qz-  
{ WKf->W  
if(!fileSplitterFetch.bDownOver) l[EnFbD6  
{ U2*g9Es  
breakWhile = false; 78v4cQ Y  
break; qc}r.'p  
} x&6SjlDb$K  
} &+?JY|u  
if(breakWhile) KgtMrT5<q  
break; stDrF1{  
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//count++; i<N[sO  
//if(count>4) (nk)'ur.  
// siteStop(); D-7PO3F:F  
} o
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System.err.println("文件下载结束！"); ~c~$2Xo  
} T~%}(0=m  
catch(Exception e){e.printStackTrace ();} ), >jBYMJ  
} M+<xX)   
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sh []OSM
 
//获得文件长度 e
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public long getFileSize() ~{,U%B  
{ z~TG~_s  
int nFileLength = -1; #rL%K3'  
try{ j rX.e  
URL url = new URL(siteInfoBean.getSSiteURL()); E,I*E{nd9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SF.4["$  
httpConnection.setRequestProperty("User-Agent","NetFox"); s)#8>s-  
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>uS?Nz5/  
int responseCode=httpConnection.getResponseCode(); B+G,v:)R6z  
if(responseCode>=400) 5"4O_JQ  
{ ?*i qg[:  
processErrorCode(responseCode); bT|NZ!V  
return -2; //-2 represent access is error I#0WN  
} mX78Av.z!  
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String sHeader; K1rF;7Y6  
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for(int i=1;;i++) }cK<2J#  
{ W=v4dy]B  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 2Y~6~*8*~  
//Utility.log(in.readLine());  y{hy  
sHeader=httpConnection.getHeaderFieldKey(i); +{V"a<D$m  
if(sHeader!=null) <qD/ #$  
{ VeixwGZ.  
if(sHeader.equals("Content-Length")) )3_I-Ia  
{ \%nFCK0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `8Y& KVhu  
break; HC0q_%j  
} aa8xo5tIp  
} (fmcWHs  
else MWv_BXQ  
break; {@1C,8n;  
} [
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} d52l)8  
catch(IOException e){e.printStackTrace ();} 
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catch(Exception e){e.printStackTrace ();} V[f-Nj Kf  
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Utility.log(nFileLength); <3dmY=  
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return nFileLength; q\Cg2[nn2  
} M_tY:v  
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//保存下载信息（文件指针位置） z=TaB^-)  
private void write_nPos() }mRus<Ax  
{ Nx~9Ug  
try{ |zD{]y?S-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Pl_4;q!$  
output.writeInt(nStartPos.length); (lwrk(  
for(int i=0;i<nStartPos.length;i++) <rUH\z5cP  
{ QUL^]6$  
// output.writeLong(nPos); 0HUSN_3F  
output.writeLong(fileSplitterFetch.nStartPos); %c%0pGn8-  
output.writeLong(fileSplitterFetch.nEndPos); 8$O=HE*  
} BZy&;P  
output.close(); ahi lp$v  
} 3w
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catch(IOException e){e.printStackTrace ();} uU v yZ  
catch(Exception e){e.printStackTrace ();} &fJ92v?%^S  
} $:M*$r^u  
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//读取保存的下载信息（文件指针位置） 
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private void read_nPos() t0_o.S  
{ rQ|^H
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try{ m,nZrap  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); _{CMWo"l  
int nCount = input.readInt(); c|<*w[%C  
nStartPos = new long[nCount]; :fI|>I ~  
nEndPos = new long[nCount]; Js7(TFQE  
for(int i=0;i<nStartPos.length;i++) " , c1z\  
{ >r%L=22+  
nStartPos = input.readLong(); #:0dqD=  
nEndPos = input.readLong(); UW7*,Bq  
} `YTagUq7  
input.close(); ^UP!y!&N  
} ,L#Qy>MOb  
catch(IOException e){e.printStackTrace ();} [Nb0&:$ay  
catch(Exception e){e.printStackTrace ();} `n%uvo}UT  
} '>[l1<d!G  
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t  
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private void processErrorCode(int nErrorCode) CZB!vh0  
{ Qs2E>C  
System.err.println("Error Code : " + nErrorCode); mm-!UsT  
} 9"Vch;U$  
}ge~Nu>w  
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//停止文件下载 Xd%c00"U  
public void siteStop() fE"Q:K6r2  
{ n4Fh*d ixg  
bStop = true; 6^U8Utx  
for(int i=0;i<nStartPos.length;i++) RUcpdeo  
fileSplitterFetch.splitterStop(); 4\'1j|nS[  
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} b%`^KEvwfo  
} UM$\{$  
//负责部分文件的抓取 pvL)BD  
**FileSplitterFetch.java )N[9r{3  
*/ ]
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package NetFox; X._skq  
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import java.io.*; WP)r5;Hv`  
import java.net.*; 06@^knm  
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public class FileSplitterFetch extends Thread { tfzIem  
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String sURL; //File URL ,~^0AtLv  
long nStartPos; //File Snippet Start Position eELJDSd BV  
long nEndPos; //File Snippet End Position OO?d[7Wt0  
int nThreadID; //Thread's ID =O= 0 D  
boolean bDownOver = false; //Downing is over :s8^nEK  
boolean bStop = false; //Stop identical K)z{R n  
FileAccessI fileAccessI = null; //File Access interface 6"@+Jz  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException MB]8iy8  
{ O;RsYs9  
this.sURL = sURL; +X[+SF)!  
this.nStartPos = nStart; o&]b\dV  
this.nEndPos = nEnd; V~j:!=b%v  
nThreadID = id; }Rujh4*  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 E(J@A'cX  
} /.1c<!  
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public void run() v&t~0jX,  
{ Hc?8Q\O:  
while(nStartPos < nEndPos && !bStop) RbPD3&.  
{ Q]j[+e  

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try{ DONXq]f:,"  
URL url = new URL(sURL); ~)!yl. H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~)5NX 4Po  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8<
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String sProperty = "bytes="+nStartPos+"-"; #-76E  
httpConnection.setRequestProperty("RANGE",sProperty); vW`Dy8`06  
Utility.log(sProperty); USF9sF0l  
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InputStream input = httpConnection.getInputStream(); \G}02h  
//logResponseHead(httpConnection); 0#\K9|.  
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byte[] b = new byte[1024]; JbT+w\o  
int nRead; #2*l"3.$.R  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) P2
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{ CPJ8G}4  
nStartPos += fileAccessI.write(b,0,nRead); a7?z{ssEi  
//if(nThreadID == 1) Ziclw)   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;bz|)[4/  
} "Zk# bQ2j  
:H9\nU1  
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Utility.log("Thread " + nThreadID + " is over!"); yV{&x
 
bDownOver = true; zNAID-5K;  
//nPos = fileAccessI.write (b,0,nRead); h"~i&T h  
} m9yi:zT%  
catch(Exception e){e.printStackTrace ();} ?'RB)M=Og7  
} E?\&OeAkO  
} 9f UD68Nob  
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//打印回应的头信息 /j7e q  
public void logResponseHead(HttpURLConnection con)
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{
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for(int i=1;;i++) Ynn:,  
{ --S1p0  
String header=con.getHeaderFieldKey(i); Sq#AnD6To  
if(header!=null) x/BtB"e*5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VU8EjuOetb  
Utility.log(header+" : "+con.getHeaderField(header)); YUGE>"{  
else fU/&e^, 's  
break; n $Nw/Vm  
} r"E%U:y3P  
} ALcin))+B  
+0,'B5 (E  
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public void splitterStop() '3%JhG)#  
{ 1omjP`]|,  
bStop = true; TJYup%q  
} rcq^mPdQ  
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>  
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} g`7C1&U*T  
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/* -|z ]Ir  
**FileAccess.java KU]co4]8^s  
*//文件访问(定位，写) Za[
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package NetFox; e0s*  
import java.io.*; ! qVuhad.  
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public class FileAccessI implements Serializable{ ppm=o4`s[  
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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 (M0"I1g|w  
RandomAccessFile oSavedFile; `i!BXOOV{  
long nPos; HZASIsl  
>-&B#Z^,  
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public FileAccessI() throws IOException 34*73WxK  
{ R"wBDWs  
this("",0); ='W=  
} m&PfZ%'[  

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public FileAccessI(String sName,long nPos) throws IOException |~K 5]  
{ a/\SPXQ/9  
oSavedFile = new RandomAccessFile(sName,"rw"); x5w5xw  
this.nPos = nPos; &nV/XLpG  
oSavedFile.seek(nPos); lQS(\}N  
} ^cUmLzM  
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*&v
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public synchronized int write(byte[] b,int nStart,int nLen) 1 5heLnei  
{ ._E 6?  
int n = -1; =,BDd$e  
try{ {})d}dEC  
oSavedFile.write(b,nStart,nLen); 0dTHF})m  
n = nLen; qix$ }(P  
} lGlh/B%  
catch(IOException e)
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{ /IxoS  
e.printStackTrace (); L[s`8u<_)z  
} XnwVK  
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return n; z|F38(%JJN  
} > `1K0?_  
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} 1^ijKn@6  
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/* pqCp>BO?O  
**SiteInfoBean.java xA'RO-a}h  
*/ :' =le*h  
package NetFox; ptc.JB6  
} =
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@  
public class SiteInfoBean { 1gA^Qv~?  
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private String sSiteURL; //Site's URL !
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private String sFilePath; //Saved File's Path %{|67h  
private String sFileName; //Saved File's Name zH13~\  
private int nSplitter; //Count of Splited Downloading File 6Y%{ YQ}s|  
2@6Qifxd@  
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public SiteInfoBean() N79?s)l:K  
{//nSplitter的缺省值为5 3Q#
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//default value of nSplitter is 5 Ez/>3:;  
this("","","",5); d4m@u$^1B  
} DO 0  
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0;L.h|R T(  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) H -K%F_#  
{ [ KDNKK  
sSiteURL= sURL; Z?<&@YQS  
sFilePath = sPath; uhm3}mWv  
sFileName = sName; h:AB`E1  
this.nSplitter = nSpiltter; ?{;7\1[4  
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v@d]*TG  
} <^w4+5sT/  
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public String getSSiteURL() V2SHF  
{ Q-?6o  
return sSiteURL; m@y<wk(  
} ;lQ>>[*  
!{?<(6;t  

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public void setSSiteURL(String value) sd _DG8V  
{ 7.*Mmx~]=  
sSiteURL = value; &u4;A[-R  
} 1d!TU=*  
d}2(G2z^  
1=_Qj}!1  
public String getSFilePath() 3Ct:AJeg  
{ 6 u1|pX8  
return sFilePath; 4iv&!hAc;  
} %l3f .  
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public void setSFilePath(String value) wzF%R{;  
{ P&h]uNu  
sFilePath = value; 0}"'A[xE  
} Db*&'32W  
I uC7Hx`z  
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public String getSFileName() &a+=@Z)kf  
{ B"rO  
return sFileName; C^fn[plL  
} d[YG&.}+8j  
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public void setSFileName(String value) AqT}^f
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{ Khh}flRy  
sFileName = value; KJv[z  
} :W9a t  
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public int getNSplitter() 0_N.s5~N  
{ 5FE&  
return nSplitter; f#\Nz>tOhE  
} A*{CT>  
+`ug?`_  
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public void setNSplitter(int nCount) 92ngSaNC  
{ BZ,{gy7g7X  
nSplitter = nCount; r%9=75HA  
} Wjli(sT#-  
} $|N\(}R  
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M
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/* x@@bC=iY$  
**Utility.java ~|S}$|Mi50  
*/ Svdmg D!  
package NetFox; &@${@  
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public class Utility { `i!fg\qnK  
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public Utility() L9]d$ r"  
{ Fw8b^ew  
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} !gcea?I  
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//线程睡眠 pwRCfR)"X  
public static void sleep(int nSecond)  7gx?LI_e  
{ o?^Rw*u0/  
try{ ByacSN  
Thread.sleep(nSecond); z3{Cp:Mn  
} vSY YetL  
catch(Exception e) >qPP_^]  
{ j^/=.cD|  
e.printStackTrace (); $EL:Jx2<  
} !;Ke#E_d  
} agq4Zy  
{B4.G8%Z  
//日志 ^v+p@k  
public static void log(String sMsg) :sttGXQX  
{ q0b*#j  
System.err.println(sMsg); DPkH:X  
} ,b:~
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">5$;{;2r  
{w@9\LsU  
public static void log(int sMsg) f`iDF+h<6  
{ !JBj%|!  
System.err.println(sMsg); u'^kpr`
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} MY^o0N  
} ;0`IFtz  
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/* HBZ6Pj  
**TestMethod.java dkeMiLm  
*/ Ko)f:=Qo  
package NetFox; @<&u;8y-Cn  
;/H/Gn+  
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public class TestMethod { Qkw?QV-`k  
k9;t3-P  
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public TestMethod() >WLHw!I!6  
{ ///xx/weblogic60b2_win.exe nFWiS~(#sW  
try{ V9Dq<y-y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Vt,P.CfdC  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zZP/C   
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5#y_EpL"  
fileFetch.start(); Zy.3yQM9i  
} B*9?mcP\  
catch(Exception e){e.printStackTrace ();} YI`BA`BQ8  
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} :98:U~d1  
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public static void main(String[] args) dK;ebg9|  
{ LIKQQ  
new TestMethod(); 0{I-x^FI  
} ,LC(Ax'.F  
} @2On`~C`  
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