http断点续传简单实现（java)

/* Pw61_ZZ4B\  
**SiteFileFetch.java ixT:)|'i  
*/ B,=H
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package NetFox; /x1![$oC0  
import java.io.*; ={xE!"  
import java.net.*; 7!JQB
 
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public class SiteFileFetch extends Thread { qCnZhJ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean k>g_Z`%<  
long[] nStartPos; //开始位置 !GNBDR
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long[] nEndPos; //结束位置 t
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]@Uq=?%  
long nFileLength; //文件长度 |VNnOM  
boolean bFirst = true; //是否第一次取文件 AQ[GO6$,%H  
boolean bStop = false; //停止标志 @("a.;1#o  
File tmpFile; //文件下载的临时信息 ?TKRjgW`@_  
DataOutputStream output; //输出到文件的输出流 E`uY1B[c  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Cy=Hy@C  
public SiteFileFetch(SiteInfoBean bean) throws IOException dKxyA"@  
{ _`:1M2=  
siteInfoBean = bean; PU1Qsb5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); trp0V4b8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]n~ilS.rkl  
if(tmpFile.exists ()) ~"k
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{ n*{sTT  
bFirst = false; <t \H^H!  
read_nPos(); :1bWVM)  
} aD$v2)RR  
else S_IUV)  
{ TmV,&['mg  
nStartPos = new long[bean.getNSplitter()]; 4QIX19{"  
nEndPos = new long[bean.getNSplitter()]; Us0EG\Y  
} Z Z:}AQ  
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} B2'i7Ps  
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public void run() #T=LR@y  
{ +w{*Xk)4  
//获得文件长度 \S!e![L/  
//分割文件 wlqpn(XR  
//实例FileSplitterFetch k@
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//启动FileSplitterFetch线程 283F)T\Rv  
//等待子线程返回 s pp f  
try{ ~2QR{; XQ  
if(bFirst) O4V.11FnW  
{ \}"$ ?d'f  
nFileLength = getFileSize(); 9|gr0&#~j  
if(nFileLength == -1) 2h1vVF3  
{ t_$2CRG#  
System.err.println("File Length is not known!"); Pn>Xbe  
} '
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else if(nFileLength == -2) t? yz  
{ iCHOv{p.  
System.err.println("File is not access!"); e3nYbWBy]  
} P>NF.BCq  
else g9Xu@N;bL  
{ K+3IWZ&+dG  
for(int i=0;i<nStartPos.length;i++) IV\'e}  
{ %~2YE  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); g|vNhq0|i  
} zU gE~  
for(int i=0;i<nEndPos.length-1;i++) F|e1"PkeoA  
{ #\ X#w<\?  
nEndPos = nStartPos[i+1]; rp!oO>F  
} 4hTMbS_;  
nEndPos[nEndPos.length-1] = nFileLength; C,ARXW1  
} \1fN0e  
} hM6PP7XH  
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//启动子线程 rLI8pA|.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; opy("qH  
for(int i=0;i<nStartPos.length;i++) Y6zbo
  
{ IJ(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8{^WY7.'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %)/P^9I6  
nStartPos,nEndPos,i);
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~&7MkkftM  
fileSplitterFetch.start(); "J[K 3  
} a!"$~y$*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 3W3ZjdV+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?"i}^B`*  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", g" .are'7  
nEndPos = " + nFileLength); o4K ~  
// fileSplitterFetch[nPos.length-1].start(); ;U.hxh;+  
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I+[>I=ewa  
//等待子线程结束 Kgi<UkFP  
//int count = 0; X[&Wkr8x '  
//是否结束while循环 ymx>i~>7J  
boolean breakWhile = false; ,^w?6?,&l}  
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while(!bStop) zxbpEJzpn  
{ 8&?s#5zA  
write_nPos(); }%'?p<^M  
Utility.sleep(500); hRrn$BdLX  
breakWhile = true; XINu=N(g  
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for(int i=0;i<nStartPos.length;i++) JGsx_V1t  
{ :UF%K>k2  
if(!fileSplitterFetch.bDownOver) 2.l Z:VLN  
{ ^Eb.:}!D6  
breakWhile = false;
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break; d4>Z8FF|1B  
} Ay5i+)MD  
} 19Mu61  
if(breakWhile) ER5gmmVP@p  
break; QLEKsX7p>  
ktFhc3);!  
:U3kW8;UMP  
//count++; qln3 k`  
//if(count>4) |"/8XA  
// siteStop(); %_RQx2  
} lOuHVa*}  
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System.err.println("文件下载结束！"); ]* F\"C@  
} j.w@
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catch(Exception e){e.printStackTrace ();} 5q;GIw^L  
} UEM(@zD]  
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7=TF.TW)  
//获得文件长度 v/68*,z[  
public long getFileSize() H%UL%l$  
{ zr+zhpp  
int nFileLength = -1; LcB]Xdsa(  
try{ ^S UPi  
URL url = new URL(siteInfoBean.getSSiteURL()); b&~4t/Vq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]b7zJUz  
httpConnection.setRequestProperty("User-Agent","NetFox"); w)kNkD  
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int responseCode=httpConnection.getResponseCode(); 2Ga7$q  
if(responseCode>=400) hbzC#@q  
{ wKZ$iGMbz  
processErrorCode(responseCode); `\T]ej}zvI  
return -2; //-2 represent access is error \>:CvTzF  
} x(etb<!jd  
#{?PbBE}  
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String sHeader; trPAYa}W  
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for(int i=1;;i++) _=Z,E.EN  
{ Xjo5v*Pu  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Rzbj  
//Utility.log(in.readLine()); s>;v!^N?u  
sHeader=httpConnection.getHeaderFieldKey(i); 4zev^FR  
if(sHeader!=null) bJRN;g  
{ 66/3|83Z  
if(sHeader.equals("Content-Length")) 5][Ztx  
{ 5R
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \`oT#|0  
break; 0B@SN)<kH  
} /y _O4  
} %{AO+u2i  
else 01r 8$+  
break; 8$85^Of  
} zVXC1u9B  
} Ir`eL  
catch(IOException e){e.printStackTrace ();} /<@SFF.  
catch(Exception e){e.printStackTrace ();} *c~T@m~DR  
!46RGU:I  
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Utility.log(nFileLength); WN{ 9  
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return nFileLength; x(hE3S#+  
} q qpgy7  
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//保存下载信息（文件指针位置） OMWbZ>jB  
private void write_nPos() U1DXeh~V  
{ lD^]\;?  
try{ =yr0bGy`-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); y4*U6+#.  
output.writeInt(nStartPos.length); u.d).da  
for(int i=0;i<nStartPos.length;i++) C8[&S&<_<  
{ &Q;sSIc  
// output.writeLong(nPos); Ss~;m']68  
output.writeLong(fileSplitterFetch.nStartPos); "x=f=;  
output.writeLong(fileSplitterFetch.nEndPos); !/}O>v~o  
} =Z P%mW&;}  
output.close(); WM| dKF  
} |uqf:V`z:  
catch(IOException e){e.printStackTrace ();} #w,Dwy  
catch(Exception e){e.printStackTrace ();} 7ePqmB<.  
} 0Sle  
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//读取保存的下载信息（文件指针位置） ?]Pmxp H}  
private void read_nPos() CN#+U,NZV  
{ lsNrAA%m  
try{ {;N,t]>8M  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]l1\? I  
int nCount = input.readInt(); a:"Uh**  
nStartPos = new long[nCount]; ^* J2'X38I  
nEndPos = new long[nCount]; UUzYbuS>&l  
for(int i=0;i<nStartPos.length;i++) =NnNN'}  
{ m@"QDMHk.  
nStartPos = input.readLong(); #JgH}|&a$  
nEndPos = input.readLong(); W%T>SpFl  
} 73V|6tmgY  
input.close(); tS
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} qQA
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catch(IOException e){e.printStackTrace ();} q*F{/N**  
catch(Exception e){e.printStackTrace ();} dRj|g  
} LV\DBDM  
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private void processErrorCode(int nErrorCode) Qr^|:U!;[z  
{ O\E
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System.err.println("Error Code : " + nErrorCode); tE@;X=  
} &j4xgh9  
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#0ETY\}ZD  
//停止文件下载 S{;sUGcu  
public void siteStop() Pl=ZRKn  
{ R%Q@  
bStop = true; b~'"^ Bts*  
for(int i=0;i<nStartPos.length;i++) PV9pa/`@  
fileSplitterFetch.splitterStop(); `S6x<J&T\/  
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} pQshUm"_  
} S`#w+C#EW  
//负责部分文件的抓取 -j73Wz  
**FileSplitterFetch.java G]+&!4  
*/ k`0>36  
package NetFox; )3~{L;q
 
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import java.io.*; G'6@+$ppS  
import java.net.*; ptDY3n~'  
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public class FileSplitterFetch extends Thread { 9?0^ap,T  
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String sURL; //File URL _9=Yvc=  
long nStartPos; //File Snippet Start Position =bHD#o|R  
long nEndPos; //File Snippet End Position `glBV`?^  
int nThreadID; //Thread's ID lrv3fPIW  
boolean bDownOver = false; //Downing is over @xbQYe%J  
boolean bStop = false; //Stop identical A9wh(P0\  
FileAccessI fileAccessI = null; //File Access interface !q9+9 *6  
2 dAB-d:k  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException zx-81fx+k  
{ \De{9v  
this.sURL = sURL; Zy o[(`y  
this.nStartPos = nStart; ~xD={9BL  
this.nEndPos = nEnd; V
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nThreadID = id; 8ELCs<xI  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 s
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} TMig-y*[  
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public void run() w,h`s.AN  
{ Cq'KoN%nQ  
while(nStartPos < nEndPos && !bStop) !{^PO<9  
{ S4G^z}{_  
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try{ #7MUJY+ 9  
URL url = new URL(sURL); KTP8?Q"n0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "J4WzA%i  
httpConnection.setRequestProperty("User-Agent","NetFox"); Cq%IE^g<  
String sProperty = "bytes="+nStartPos+"-"; ||;hciO  
httpConnection.setRequestProperty("RANGE",sProperty); <$X3Hye  
Utility.log(sProperty); BZR:OtR^  
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:.$3vaZ@  
InputStream input = httpConnection.getInputStream(); }[4r4 1[  
//logResponseHead(httpConnection); ~g5[$r-u-u  
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byte[] b = new byte[1024]; @ Wd9I;hWv  
int nRead; ~},=OF-b  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) w]]8dz  
{ UPG9)aF  
nStartPos += fileAccessI.write(b,0,nRead); DP3PYJ%+B  
//if(nThreadID == 1) BDR.AZ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8xccp4  
} 3?1`D/  
;*:Pw?'  
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Utility.log("Thread " + nThreadID + " is over!"); eD*A)  
bDownOver = true; P;Ga4Q.  
//nPos = fileAccessI.write (b,0,nRead); `QyO`y=?[Y  
} {&\jW
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catch(Exception e){e.printStackTrace ();} =5kY6%E7c  
} Mz~M3$$9n  
} OoA|8!CFa  
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//打印回应的头信息 hM{{\yZS  
public void logResponseHead(HttpURLConnection con) Uc@
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{ 4`!Z$kt  
for(int i=1;;i++) Jo@|"cE=  
{ no< ^f]33  
String header=con.getHeaderFieldKey(i); @>W(1mRi  
if(header!=null) Z@]e{zO  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); . r[Hu40p  
Utility.log(header+" : "+con.getHeaderField(header)); +f@U6Vv  
else rEv$+pP  
break; *a#rM"6P  
} 4cl\^yD  
} 0@H|n^Md#  
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public void splitterStop() F.w5S!5Q  
{ .HkL2m  
bStop = true; ?TU}~}  
} t.`@{R$hoA  
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/.Ww6a~  
} r[lF<2&*R  
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/* D"ND+*Q[X  
**FileAccess.java b\-&sM(W"  
*//文件访问(定位，写) f]JM /  
package NetFox; K }Vv4x1U  
import java.io.*; Xq
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public class FileAccessI implements Serializable{ eS<lwA_  
@8;W\L$~1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /J:bWr  
RandomAccessFile oSavedFile; BV>\ McI+  
long nPos; .pN`;*7`  
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[&&1j@LQ*  
public FileAccessI() throws IOException m0cP(  
{ rzh#CnL3  
this("",0); ML( Eo  
} L:1^Kxg  
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public FileAccessI(String sName,long nPos) throws IOException +(C6#R<LI  
{ ?sMP~RHQ  
oSavedFile = new RandomAccessFile(sName,"rw"); 6y6<JR-V2k  
this.nPos = nPos; ~:3QBMk::  
oSavedFile.seek(nPos); DsT>3  
} 34d3g  
l,,>& F  
++V=s\d7  
public synchronized int write(byte[] b,int nStart,int nLen) +;#Y]xy:  
{ 7tcPwCc{  
int n = -1; ],RdySN&  
try{ K)\M5id]  
oSavedFile.write(b,nStart,nLen); dVsE^jsL  
n = nLen; $D}{]MN.  
} Mi/&f   
catch(IOException e) WnGGo'
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{ 2UFv9  
e.printStackTrace (); )e a:Q?  
} (Nx;0"5IX  
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return n; op6CA"w  
} 1. rj'  
@ ]/AjjLt  
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} /ew Ukc8,  
}w1~K'ck}>  
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/* *{yK 8  
**SiteInfoBean.java {6~l$  
*/ []A%<EI7  
package NetFox; /k<WNZM  
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public class SiteInfoBean { AKRTB
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private String sSiteURL; //Site's URL US%
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private String sFilePath; //Saved File's Path DXa-rk8  
private String sFileName; //Saved File's Name Sp^9&^  
private int nSplitter; //Count of Splited Downloading File t| 'N+-T3  
uvV;Mlo]  
Qbyv{/  
public SiteInfoBean() qfK`MhA}  
{//nSplitter的缺省值为5 '*k'i;2/1  
//default value of nSplitter is 5 tWoh''@#  
this("","","",5); GF5^\Rf  
} E5N{j4\F  
ea~:}!-P  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 2c:#O%d(  
{ =<NljOR4`  
sSiteURL= sURL; k}0^&Quc4  
sFilePath = sPath; RhvfC5Hq  
sFileName = sName; "B8"_D&  
this.nSplitter = nSpiltter; e`v`XSA[p  
@$2))g`  
%o:2^5\W  
} I<8sI%,s  
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public String getSSiteURL() >+ 4huRb  
{ 9`w)  
return sSiteURL; Tp9-niW  
} |)K]U  
h?FmBK'BAd  
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public void setSSiteURL(String value) qq1-DG  
{ mBG=jI "xh  
sSiteURL = value; BYo/57&:  
} mUz\ra;z  
6^c>,.R  
#~.w&~:  
public String getSFilePath() !Wy[).ZAf  
{ O=dJi9;`#_  
return sFilePath; A6pj
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} y:vxE8$Q  
Wf&W^Q  
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public void setSFilePath(String value) =T7A]U]  
{ 4)<~4 '  
sFilePath = value; (Gw,2-A  
} }Iz7l{al  
K&U7H:  
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public String getSFileName() =l0Jb#d  
{ }QsZ:J.  
return sFileName; v^_mFp-}\  
} {|yob4N  
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public void setSFileName(String value) yin'vgQ  
{ ?l$Nf@-  
sFileName = value; 7zv1wb  
} )5.C]4jol  
&%_& 8DkG  
@j4U^"_QB  
public int getNSplitter() Eb=#9f%y>&  
{ vQa'S-@u  
return nSplitter; kee|42E  
} f7'q-  
a+9*@z2  
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public void setNSplitter(int nCount) F|HJH"2*&q  
{ 6O22P?v  
nSplitter = nCount; \J6hI\/4^  
} |/|  
} `WOYoec   
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/* bI y sl  
**Utility.java >R2SQA o  
*/ ((^sDE6(  
package NetFox; JMS(9>+TA  
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public class Utility { bLnrbid  
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public Utility() hG_?8:W8HT  
{ gn{=%`[  
@Kgl%[NmX  
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} _6Eu2|vM&  
D>!6,m2  
//线程睡眠 eJo3 MK  
public static void sleep(int nSecond) x+@&(NMP5  
{ :~ A%#  
try{ !P$'#5mr  
Thread.sleep(nSecond); Z^9/v  
} 3s>'hn  
catch(Exception e) 1H,g=Y4f%  
{ 7 ua6l[c  
e.printStackTrace (); 8v)_6p(<x8  
} ,JEbd1Uf  
} >z`,ch6~  
34QfgMyH  
//日志 }elH75[64  
public static void log(String sMsg) tyDY'W\]  
{ yt+}K)Hz  
System.err.println(sMsg); Ji;mHFZ*FU  
} "W#t;;9Wz  
)){xlFA}  
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public static void log(int sMsg) {@u<3 s  
{ XIWm>IQ[)  
System.err.println(sMsg); o."rxd  
} Sc]P<F7N]  
} a0*2) uL}  
8:.nEo'  
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/* Ft@Wyo`^  
**TestMethod.java #2tCV't  
*/ ZE`lr+_Y  
package NetFox; ==cd>03()  
60Z]M+8y8  
E&B{5/rv  
public class TestMethod { to6;?uC+|i  
z\/53Sy<  
6TH!vuQ1(  
public TestMethod() .]|Zf!>}s  
{ ///xx/weblogic60b2_win.exe QI_59f>  
try{ ]/T-t1D  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); x>~p;z#VX  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~B$b)`*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Y1dVM]l  
fileFetch.start(); @S 6u9v  
} D^Ys)- d  
catch(Exception e){e.printStackTrace ();} `Vq`z]}  
^\:2}4Uj_  
jvzBh-!  
} * \HRw +cL  
;:m&#YJV  
M)cGz$Q|  
public static void main(String[] args) /dDzZ%/@  
{ E-1"+p  
new TestMethod(); Bfd-:`Jk  
} Vdn.)ir~P  
} @rb l^  
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