http断点续传简单实现（java)

/* D9c8#k9Y.  
**SiteFileFetch.java -acW[$t  
*/ } h
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package NetFox; z/rN+  ,  
import java.io.*; "Rs^0iT7>  
import java.net.*; K=Fcy#,f  
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public class SiteFileFetch extends Thread { +|( eP_  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~&4,w9b)j  
long[] nStartPos; //开始位置 it>FG9hVo  
long[] nEndPos; //结束位置 mKnkHGM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 D@4hQC\  
long nFileLength; //文件长度 A"z')  
boolean bFirst = true; //是否第一次取文件 T?7ZF+yo6  
boolean bStop = false; //停止标志 OjeM#s#N!  
File tmpFile; //文件下载的临时信息 JYKA@sZHe  
DataOutputStream output; //输出到文件的输出流 [>?B`1;@  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） \kWceu}H,  
public SiteFileFetch(SiteInfoBean bean) throws IOException )Hlr 09t=]  
{ +\.gdL)  
siteInfoBean = bean; rMf& HX  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 4U>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); `t ZvIy*  
if(tmpFile.exists ()) :fpYraBM  
{ /k}vm3  
bFirst = false; %t%+;(M9  
read_nPos(); b9w9M&?fT  
} p#J}@a  
else  O,xU+j~)  
{ Q} f=Ye(&}  
nStartPos = new long[bean.getNSplitter()]; kfA%
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nEndPos = new long[bean.getNSplitter()]; N9:xtrJ]_J  
} jt-ayLq  
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} `<Zp!Hl(j  
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public void run() > -Jd@7-  
{ bv$)^  
//获得文件长度 $N5}N\C:a  
//分割文件 V!3O 1  
//实例FileSplitterFetch /o![%&-l  
//启动FileSplitterFetch线程 81H04L9K 7  
//等待子线程返回 @;d(>_n  
try{ aLuxCobV  
if(bFirst) aeE9dV~  
{ T3)/?f?|  
nFileLength = getFileSize(); *wyaBV?*K  
if(nFileLength == -1) J0lTp /  
{ =JNoC01D  
System.err.println("File Length is not known!"); qV^,muyoG  
} 0 Co_,"  
else if(nFileLength == -2) WQ=C5^u  
{ _i6G)u&N  
System.err.println("File is not access!"); "i4@'`r  
} ;l5F il,3  
else F ~ /{1Q*  
{ e [3sWv  
for(int i=0;i<nStartPos.length;i++) x@Z?DS$)  
{ =f{V<i~q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); f(7/  
} !}Cd_tj6  
for(int i=0;i<nEndPos.length-1;i++) oC.:mI  
{ ~0t]`<y=  
nEndPos = nStartPos[i+1]; tX&
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} {&"rv<p  
nEndPos[nEndPos.length-1] = nFileLength; -&D~TL#  
} [|xHXcW  
} x:"_B  
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T
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//启动子线程 ?fc({zb  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^cDHyB=v4d  
for(int i=0;i<nStartPos.length;i++) .0cm mpUNq  
{ -GDX#A-J  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r^VH [c@c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), hf8=r5j=  
nStartPos,nEndPos,i); eB<R@a|?S  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /)MzF6  
fileSplitterFetch.start(); =MRg  
} W!2(Ph*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9]Uvy|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Bj;Fy9[yb  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", AnfJyltS  
nEndPos = " + nFileLength); $^y6>@~  
// fileSplitterFetch[nPos.length-1].start(); Fla,#uB  
%#yC
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//等待子线程结束 = %\;7  
//int count = 0; 2r,K/'  
//是否结束while循环 'h.{fKG]ME  
boolean breakWhile = false; "<t/*$
42  
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while(!bStop) =sPY+~<o  
{ 8 POrD8B  
write_nPos(); J,_I$* _0  
Utility.sleep(500); $j)Er.!9|R  
breakWhile = true; %f#3;tpC8  
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for(int i=0;i<nStartPos.length;i++) |Xlc2?e  
{ @w[WG:-+  
if(!fileSplitterFetch.bDownOver) _hMMm6a|  
{ qi.|oL9p  
breakWhile = false; wtndXhVC4>  
break; \3hhM}6)DM  
} [58xT>5`m  
} 5<<e_n.2q  
if(breakWhile) =oV8!d%]  
break; <:W]uT  
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//count++; l=`)yc.  
//if(count>4) ;l[/<
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// siteStop(); A5Qzj]{ba  
} =4/LixsV|  
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System.err.println("文件下载结束！"); MRZWfc  
} 4~53%=+  
catch(Exception e){e.printStackTrace ();} /x"gpKwsB  
} DzkE*vR  
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//获得文件长度 \_#0Z+pX  
public long getFileSize() WOZf4X`[  
{ n6ETWjP  
int nFileLength = -1; ^VR1whCrx  
try{ 8*;G\$+  
URL url = new URL(siteInfoBean.getSSiteURL()); Z=_p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3/H^YM @  
httpConnection.setRequestProperty("User-Agent","NetFox"); 57'=Qz52  
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int responseCode=httpConnection.getResponseCode(); &,4^LFZW  
if(responseCode>=400) SXSH9;j  
{ WIb\+!  
processErrorCode(responseCode); a.v$+}+.[,  
return -2; //-2 represent access is error a\$PqOB!  
} +[V[{n  
iNZ'qMH22  
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String sHeader; zO<EbqNe!  
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for(int i=1;;i++) .7ESPr  
{ 2-ev7:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); mHE4Es0  
//Utility.log(in.readLine()); Z~F% K~(  
sHeader=httpConnection.getHeaderFieldKey(i); T {a%:=`  
if(sHeader!=null) 5YUn{qtD  
{ #IDDKUE  
if(sHeader.equals("Content-Length")) .^N+'
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{ *,-)4)7d  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *r!1K!c  
break; wh l)^D  
} W1f]A#t<  
} >V;JI;[  
else XtRfzqg?K  
break; M@UkXA
}  
} ez%RWck  
} udX4SBq-pC  
catch(IOException e){e.printStackTrace ();} wa6DJ  
catch(Exception e){e.printStackTrace ();} c5>&~^~>Tx  
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Utility.log(nFileLength); %4Ylq|d  
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return nFileLength; G'q7@d{'  
} <~!7?ak  
Pk T&zSQA  
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//保存下载信息（文件指针位置） i)Vqvb0Q  
private void write_nPos() b{)9?%_  
{ #dE#w#=r  
try{ J\b,rOIf  
output = new DataOutputStream(new FileOutputStream(tmpFile)); m{`O.6#O  
output.writeInt(nStartPos.length); P.$U6cq  
for(int i=0;i<nStartPos.length;i++) lSC3m=4g  
{ ?q1&(g]qO  
// output.writeLong(nPos); UTc$zc7  
output.writeLong(fileSplitterFetch.nStartPos); ca*USM  
output.writeLong(fileSplitterFetch.nEndPos); 64z9Yr@  
} L.$9ernVY  
output.close(); MI0'ou8l  
} s<5q%5ix3  
catch(IOException e){e.printStackTrace ();} u{"o*udU  
catch(Exception e){e.printStackTrace ();} EC&t+"=R  
} N*$<K
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//读取保存的下载信息（文件指针位置） {6^c3R[  
private void read_nPos() C_dsYuQ5R  
{ ~;_]U[eOL  
try{ GeWB"(t  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); E)3B)(@&P  
int nCount = input.readInt(); PvBx<i}A  
nStartPos = new long[nCount]; cEnkt=  
nEndPos = new long[nCount]; P5*:r3>  
for(int i=0;i<nStartPos.length;i++) 90|p]I%  
{ nS"K dPM  
nStartPos = input.readLong(); 9*GwW&M%1_  
nEndPos = input.readLong(); :k6|-A2  
} M(HU^?B{'  
input.close(); #`RYKQwB  
} =xQ7:TB  
catch(IOException e){e.printStackTrace ();} fs&J%ku\  
catch(Exception e){e.printStackTrace ();} A9qCaq{  
} cR}}NF  
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private void processErrorCode(int nErrorCode) U8]L3&~  
{ X5U_|XK6Y  
System.err.println("Error Code : " + nErrorCode); T#6']D  
} q#LwM]<.@>  
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//停止文件下载 |Yh-`~~A"  
public void siteStop() 5'@J}7h  
{ Wg[?i C*~  
bStop = true; g9}u6q  
for(int i=0;i<nStartPos.length;i++) Y'i0=w6G  
fileSplitterFetch.splitterStop(); V2g,JFp&  
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+L;[-]E8  
} D%(9ot{!e  
} Dx$74~2e  
//负责部分文件的抓取 z}.!q{Q  
**FileSplitterFetch.java #pBAGm3  
*/ @g9j+DcU  
package NetFox; 2`+
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import java.io.*; g-E!*K  
import java.net.*; }oYR.UH  
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@ v/%^  
public class FileSplitterFetch extends Thread { u><ax  
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String sURL; //File URL 2_
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long nStartPos; //File Snippet Start Position (9';zw   
long nEndPos; //File Snippet End Position VD/Wl2DK  
int nThreadID; //Thread's ID 96]lI3c  
boolean bDownOver = false; //Downing is over }r]WB)_w  
boolean bStop = false; //Stop identical r/HKxXT  
FileAccessI fileAccessI = null; //File Access interface s#`%c({U|  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException aQCbRS6  
{ =vT3SY  
this.sURL = sURL; n} GIf&  
this.nStartPos = nStart; }U7>_b2  
this.nEndPos = nEnd; qnW5I_
]  
nThreadID = id; l<PGUm:_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 583ej2HPg  
} #jd?ocoY  
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@
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public void run() HQ7-,!XO  
{ daWmF  
while(nStartPos < nEndPos && !bStop) >4ebvM 0|  
{ '97)c7E  
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' :g8a=L  
try{ >ly= O  
URL url = new URL(sURL); j:"+/5rV8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D4s*J21)D  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7 tF1g=\  
String sProperty = "bytes="+nStartPos+"-"; [4 g5{eX  
httpConnection.setRequestProperty("RANGE",sProperty); .2Q`. o)  
Utility.log(sProperty); Wq0h3AjR  
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InputStream input = httpConnection.getInputStream(); E?y0UD[8J  
//logResponseHead(httpConnection); NhCO C  
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byte[] b = new byte[1024]; K).X=2gjY  
int nRead; tH5f;mY,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \@pl:Os  
{ [aO"9
 
nStartPos += fileAccessI.write(b,0,nRead); |?s%8c'w=  
//if(nThreadID == 1) PdMx6 Ab  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Mb\~WUWI  
} &w2
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{ YJ.BWr  
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Utility.log("Thread " + nThreadID + " is over!"); ~Az20RrK)  
bDownOver = true; ETH`.~%  
//nPos = fileAccessI.write (b,0,nRead); ex'd^y  
} #Q 2$
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catch(Exception e){e.printStackTrace ();} >G' NI?$  
} `C=!8q  
} dulW!&*No  
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//打印回应的头信息 .{7?Y;_(  
public void logResponseHead(HttpURLConnection con) oVoTnGNM6  
{ TT.EQv5  
for(int i=1;;i++) i.cSD%*  
{ uFSgjWJ#~  
String header=con.getHeaderFieldKey(i); %!(6vm>8  
if(header!=null) 7Yk6C5C  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); UbC)XiO  
Utility.log(header+" : "+con.getHeaderField(header)); 85"DS-+e  
else dAEz hR[=  
break; /,Ln)?eD  
} ]_d(YHYf  
} 5tP0dQYd
 
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public void splitterStop() 4mshB  
{ +;Cq>1x,  
bStop = true; &HFMF)NA  
} #%k5s?cP@  
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} LrF'Hd=O  
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/* m\1*/6oV  
**FileAccess.java {nryAXK  
*//文件访问(定位，写) =:~~RqHl  
package NetFox; @#VxjXW^  
import java.io.*; (4M#(I~cE  
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public class FileAccessI implements Serializable{ mWmDH74  
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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 B'
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RandomAccessFile oSavedFile; gQ?>%t]  
long nPos;
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q n=6>wP  
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public FileAccessI() throws IOException O(&EnNm[2  
{ EHzU`('?[  
this("",0); zXcSE"   
} 7:x.08  
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public FileAccessI(String sName,long nPos) throws IOException }{iR+MX  
{ 14oD^`-t  
oSavedFile = new RandomAccessFile(sName,"rw"); fD,#z&  
this.nPos = nPos; 3XL0Pm  
oSavedFile.seek(nPos); QR4v6*VpD  
} Yo7ctwzdH;  
*ArzXhs[  
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public synchronized int write(byte[] b,int nStart,int nLen) Fi7pq2  
{ ,{'~J @  
int n = -1; ^4s#nf:}  
try{ ?[XH`c,  
oSavedFile.write(b,nStart,nLen); '?3Hy|}  
n = nLen; 3D<P [.bS  
} 2jx""{  
catch(IOException e) NKGo E/  
{ :+E>UzT  
e.printStackTrace (); lV]l`$XI  
} 'J!P:.=a>  
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return n; yD(/y"P,9  
} 3kKXzIh  
-
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} m{b(^K9}  
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/* w'L;`k;Q  
**SiteInfoBean.java &X|z(vSJ$  
*/ u;=("S{"0  
package NetFox; <#`<Ys3b*!  
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public class SiteInfoBean { @Chj0wWZ>  
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private String sSiteURL; //Site's URL
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private String sFilePath; //Saved File's Path bZ3CJ f&mE  
private String sFileName; //Saved File's Name :Ur%.0  
private int nSplitter; //Count of Splited Downloading File (%I`EAR  
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public SiteInfoBean() 7Kh+m@q.  
{//nSplitter的缺省值为5 tM@TT@.t~  
//default value of nSplitter is 5 pd

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this("","","",5); +d#ZSNu/  
} v t(kL(}v  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) DbOWnXV"o  
{ _Z8zD[l  
sSiteURL= sURL; [$] JvF  
sFilePath = sPath; C 
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sFileName = sName; Nk^#Sa?  
this.nSplitter = nSpiltter; u!g<y  
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} *a$z!Ma3h  
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public String getSSiteURL() DM>j@(uWF  
{ XqJ@NgsY  
return sSiteURL; C/]0jAAE7  
} {H0B"i  
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public void setSSiteURL(String value)
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{ =&}dP%3LC)  
sSiteURL = value; "I+wU`AIek  
} yYF80mnJz  
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public String getSFilePath() 8c~b7F \  
{ ~G"6^C:x  
return sFilePath; ql8CgL  
} 4'X^YBm  
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}|A%2!Q}  
public void setSFilePath(String value) n{UB^-}5  
{ 8+GlM+>4  
sFilePath = value; Pb[wysy  
} ,T1t`  
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public String getSFileName() L4Kkbt<x  
{ seq S*^7  
return sFileName; *K0CUir|  
} [QL)6Xr  
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public void setSFileName(String value) /4=O^;  
{ e'7!aysj  
sFileName = value; dq|z;,`  
} >B~p[wh0  
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C\EV$U,  
public int getNSplitter() QEtZ]p1H@  
{ ea7v:#O[S  
return nSplitter; BH%eu 7`t  
} tR2IjvmsX  
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public void setNSplitter(int nCount) oOJN?97!k  
{ E#_}y}7JY  
nSplitter = nCount; zFv>'1$  
} 2&5"m;<  
} {mueP6Gz@J  
L! Q&?xP  
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/* }vcC4 =t/  
**Utility.java KZ<
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*/ +]*?J1Y8Z  
package NetFox; sFB; /*C  
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public class Utility { a"hlPJlG  
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public Utility() 6)DYQ^4y  
{ c< \:lhl  
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CXJ0N  
} })ss.  
J}<k`af  
//线程睡眠 .cle^P  
public static void sleep(int nSecond) )LH nDx  
{ 3!ulBiMh  
try{ eK3J9;X  
Thread.sleep(nSecond); HtS:'~DYo  
} :2  
catch(Exception e) g^8bY=* .  
{ '&s:,o-p  
e.printStackTrace (); 875V{fvPBU  
} qTiX;e\W  
} }U+gJkY2  
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//日志 ,/JrQWgD  
public static void log(String sMsg) xae}8E  
{ RI cA)I.  
System.err.println(sMsg); zneK)C8&q3  
}  :E'38~  
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public static void log(int sMsg) ?u 9) GJO[  
{ t</Kel|D  
System.err.println(sMsg); /koNcpJ  
} !L-.bve!  
} 9k2HP]8=[{  
<[[DS%(M^  
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/* bg[q8IBCd
 
**TestMethod.java R}Z"Yxx  
*/ g24)GjDi  
package NetFox; fl+ [(x<  
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public class TestMethod { Wc03Sv&FZ  
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public TestMethod() nM)]  
{ ///xx/weblogic60b2_win.exe ){R_o
5  
try{ ?$F:S%eH  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); `h :&H,N  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0qZ{:}`3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); t'0r4&\  
fileFetch.start(); luLm:NWUM  
} \wO)w@"  
catch(Exception e){e.printStackTrace ();} 8R8J./i.K  
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} ~"brfjd|  
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public static void main(String[] args) <k/'mBDk  
{ u|9^tHT>  
new TestMethod(); rWi
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} %+FM$xyJ  
} =@V4V} ?  
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