http断点续传简单实现（java)

/* im1]:kr7  
**SiteFileFetch.java #j;&g1  
*/ o'D6lkf0  
package NetFox; vx-u+/\  
import java.io.*; P5aHLNit  
import java.net.*; gQ/zk3?k  
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public class SiteFileFetch extends Thread { ~yO.R)4v  
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SiteInfoBean siteInfoBean = null; //文件信息Bean RHB>svT^K>  
long[] nStartPos; //开始位置 cQ+V4cW Z  
long[] nEndPos; //结束位置 0n3O;=[aV  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b5H[~8mf  
long nFileLength; //文件长度 ICV67(Ui  
boolean bFirst = true; //是否第一次取文件 S!g&&RDx  
boolean bStop = false; //停止标志 <y`yKXzBUV  
File tmpFile; //文件下载的临时信息 e1+ %c9UQ  
DataOutputStream output; //输出到文件的输出流 q:nYUW o  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ;%U`lE0  
public SiteFileFetch(SiteInfoBean bean) throws IOException T]E$H, p  
{ qtgj"4,:`  
siteInfoBean = bean; MK=:L  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v3@)q0@  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1 k H  
if(tmpFile.exists ()) nre8 F  
{ |t.WPp5,  
bFirst = false;  i4Fw+Z  
read_nPos(); Hj2P|;2S  
} $1UN?(r  
else w1s#8:  
{ ?|8
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nStartPos = new long[bean.getNSplitter()]; Z"E+ TX  
nEndPos = new long[bean.getNSplitter()]; 2Jj`7VH>  
} N*o+
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} TYLf..i<  
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public void run() ,cbP yg  
{ 2poU\
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//获得文件长度 _ k>j?j-  
//分割文件 /?by4v73P  
//实例FileSplitterFetch A 7TP1  
//启动FileSplitterFetch线程 3HfT9  
//等待子线程返回 -98bX]8  
try{ Y3-15:-  
if(bFirst) wV(_=LF  
{ n}._Nb 5  
nFileLength = getFileSize(); (r7~ccy4  
if(nFileLength == -1)
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{ $x`U)pv  
System.err.println("File Length is not known!"); XvdK;  
} g=Qj9Z  
else if(nFileLength == -2) '9RHwKu&s  
{ K
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System.err.println("File is not access!"); I@x*>  
} xi|iV1A  
else I*}:C  
{ w#"c5w~  
for(int i=0;i<nStartPos.length;i++) [%3{mAd  
{ 'rd{fe_g!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); V:l; 2rW  
} 0eb`9yM  
for(int i=0;i<nEndPos.length-1;i++) >0~y"~M  
{ tb_
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nEndPos = nStartPos[i+1]; 2>s:wABb /  
} Ou,B3kuQ+  
nEndPos[nEndPos.length-1] = nFileLength; &Cdd  
} 67f#Z&r2k  
} mk[=3!J  
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//启动子线程 _<5> E  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^mG-O  
for(int i=0;i<nStartPos.length;i++) 2#|Q=rWB  
{ 6idYz"P %  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hQX|wWh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), v|n.AGn  
nStartPos,nEndPos,i); OZ7MpQ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U[Z1@2zLx  
fileSplitterFetch.start(); ^yBx.GrQc  
} D4 e)v%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i%-c/ lop  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Q@l3XNH|c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^>]p4Q3 6  
nEndPos = " + nFileLength); bD49$N?>  
// fileSplitterFetch[nPos.length-1].start(); F1MPo;e  
,!Ah+x  
!f"@pR6  
//等待子线程结束 o<%Sr*  
//int count = 0;
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//是否结束while循环 )%UO@4  
boolean breakWhile = false; 9#pl BtQ**  
!QC->  
N!H
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while(!bStop) 'm-s8]-W  
{ a*??!  
write_nPos(); LoNz 1KJL  
Utility.sleep(500); w'U;b  
breakWhile = true; %Wu3$b  
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for(int i=0;i<nStartPos.length;i++) o2Z# 5-  
{ H?O*  
if(!fileSplitterFetch.bDownOver) X;zy1ZH  
{ }X}fX#[  
breakWhile = false; !9V_U  
break; M|76,2u   
} j>P>MdZtk  
} /SP^fB*y  
if(breakWhile) B;_M52-B  
break; 5a4;d+  
et)A$'Q  
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//count++; 8Gs{Zfp!D  
//if(count>4) wVw3YIN#  
// siteStop(); _`ot||J  
} ~ dmyS?Or  
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System.err.println("文件下载结束！"); /|hKZTZJdN  
} N{oD1%  
catch(Exception e){e.printStackTrace ();} $FCLo8/=  
} 
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//获得文件长度 g6r3V.X'  
public long getFileSize() / 1E6U6  
{ K]Ed-Tz8QZ  
int nFileLength = -1; YHg4WW$  
try{ $40t
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URL url = new URL(siteInfoBean.getSSiteURL()); kg9ZSkJr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |P~TZ  
httpConnection.setRequestProperty("User-Agent","NetFox"); aq[kKS`  
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int responseCode=httpConnection.getResponseCode(); eX$u  
if(responseCode>=400) 42X[Huy]  
{ 2z&HT SI  
processErrorCode(responseCode); QnVYZUgJeV  
return -2; //-2 represent access is error \vojF\  
} /R@eOl}D  
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String sHeader; bi[vs|  
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for(int i=1;;i++) [ 98)
7  
{ lYD-
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LB U]^t@ M  
//Utility.log(in.readLine()); wVV'9pw}  
sHeader=httpConnection.getHeaderFieldKey(i); If2f7{b  
if(sHeader!=null) l}K{=%U>7  
{ I`zn#U'  
if(sHeader.equals("Content-Length")) 5
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{ %A:<rO85o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); exZa:9 sp  
break; +-K-CXt  
} YG!~v~sV  
} 4GeWo@8h  
else ;1K.SDj  
break; x4R[Q&:M  
} U $e-e/  
} !&?(ty^F  
catch(IOException e){e.printStackTrace ();} 0
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catch(Exception e){e.printStackTrace ();} 3zv_q&+8b  
0ir]  
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Utility.log(nFileLength); qAHQZKk  
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return nFileLength; -7$7TD`'7  
} `a98+x?JF  
7_ZfV? .  
/vBOf;L  
//保存下载信息（文件指针位置） C.Y]PdYyj  
private void write_nPos() kk )9!7  
{ F@)wi0  
try{ M7BJ$fA0E  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^4h/6^b0c  
output.writeInt(nStartPos.length); <jY"+@rF  
for(int i=0;i<nStartPos.length;i++) bK<'J=#1  
{ Mb"i}Yt{  
// output.writeLong(nPos); gW$X8ECX  
output.writeLong(fileSplitterFetch.nStartPos); `o)rAD^e  
output.writeLong(fileSplitterFetch.nEndPos); %F]4)XeW-+  
} oj;Rh!O  
output.close(); fiES6
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} C`%cPl  
catch(IOException e){e.printStackTrace ();} OpW4@le_r  
catch(Exception e){e.printStackTrace ();} 9)];l?l  
} )zf&`T  
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[;  
//读取保存的下载信息（文件指针位置） ( Y'q%$  
private void read_nPos() 1#gveHm]-G  
{ mi`!'If0)  
try{ -1DQO|q
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); M._9/ *C U  
int nCount = input.readInt(); M]v
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nStartPos = new long[nCount]; .m9s+D]fI  
nEndPos = new long[nCount]; PB(mUD2"r  
for(int i=0;i<nStartPos.length;i++) &k+jVymH  
{ 4w<U%57  
nStartPos = input.readLong(); f]jAa?d T&  
nEndPos = input.readLong(); 6X$]d^)h{  
} iqRk\yq<  
input.close(); Y1h8O%?  
} [z5pqd-  
catch(IOException e){e.printStackTrace ();} WA\ P`'lg  
catch(Exception e){e.printStackTrace ();} `07xW*K(\Y  
} G\@uj>Z  
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private void processErrorCode(int nErrorCode) 7y""#-}V[r  
{ )! Jo7SR  
System.err.println("Error Code : " + nErrorCode); yM`J+tq  
} Y(h86>z*w  
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//停止文件下载 ,9SBGxK5`  
public void siteStop() w@ALl#z;}  
{ ^_0zO$z,  
bStop = true; p2cwW/^V  
for(int i=0;i<nStartPos.length;i++) (&H-v'a}3  
fileSplitterFetch.splitterStop(); H$bu*o-Z  
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} qRlS^=#  
} >> yK_yg  
//负责部分文件的抓取 F%Oy4*4  
**FileSplitterFetch.java yr8 b?m.x  
*/ ]q~_  
package NetFox; G6]W'Kk  
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import java.io.*; :08b&myx  
import java.net.*; #;4<dDVy  
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public class FileSplitterFetch extends Thread { 2#%@j6  
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String sURL; //File URL M
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long nStartPos; //File Snippet Start Position F6^Xi"R[  
long nEndPos; //File Snippet End Position _=!Rl#  
int nThreadID; //Thread's ID #29m <f_n  
boolean bDownOver = false; //Downing is over _ `5?/\7  
boolean bStop = false; //Stop identical $2I^ ;5r[  
FileAccessI fileAccessI = null; //File Access interface 4BF \-lq~  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vo<'7,  
{ ;:nx6wi  
this.sURL = sURL; O1]L4V1iH  
this.nStartPos = nStart; wyWe2d  
this.nEndPos = nEnd; /&1FgSARK  
nThreadID = id; moz*=a  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !(2rU@.  
} sa6/$  
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public void run() b{4@~>i  
{ +OEqDXR+_  
while(nStartPos < nEndPos && !bStop) 'y_<O|-  
{ s9^r[l@W0U  
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try{ 9vX~gh{]~  
URL url = new URL(sURL); Q1hHK'3w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +8p4\l$<`  
httpConnection.setRequestProperty("User-Agent","NetFox"); \;#T.@c5  
String sProperty = "bytes="+nStartPos+"-"; iwM$U( 9  
httpConnection.setRequestProperty("RANGE",sProperty); J[0o6  
Utility.log(sProperty); .:dy d  
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InputStream input = httpConnection.getInputStream(); gu:8+/W8L  
//logResponseHead(httpConnection); T)N_~f|  
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byte[] b = new byte[1024]; ' 5tk0A  
int nRead; q)N]*~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^UJB%l  
{ KAkD" (!  
nStartPos += fileAccessI.write(b,0,nRead); =Pj+^+UM  
//if(nThreadID == 1) |-+IF,j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4zo^ b0v  
} =o_Ua^mr  
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Utility.log("Thread " + nThreadID + " is over!"); ,76xa%k(U|  
bDownOver = true; L'A9TW2  
//nPos = fileAccessI.write (b,0,nRead); }Zuk}Og9+  
} {~*^jS']5  
catch(Exception e){e.printStackTrace ();} Ij w{g%  
} @*>kOZ(3  
} }X|*+<  
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mc FSWmq  
//打印回应的头信息 p<[gzmU9\b  
public void logResponseHead(HttpURLConnection con) =5l20 Um  
{ _EEOBa
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for(int i=1;;i++) 3aX/)v.:4  
{ 2wX4e0cOI4  
String header=con.getHeaderFieldKey(i); Xg4iH5!E  
if(header!=null) MJ.K,e  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); nXRT%[o&  
Utility.log(header+" : "+con.getHeaderField(header));
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else !vfbgK  
break; THN//}d  
} WWBm*?U  
} HP,sNiw  
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public void splitterStop() Py72:;wn  
{ -|.Izgc  
bStop = true; n5qg6(Tl]  
} XK+" x!   
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} a]S0|\BkN  
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; <NK  
/* '((pW  
**FileAccess.java {3LAK[C  
*//文件访问(定位，写) Tf*DFyr  
package NetFox; 4AWL::FU5  
import java.io.*; y3+iADo.p  
$S6%a9m   
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public class FileAccessI implements Serializable{ DWwPid} "  
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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 7{JIHY+  
RandomAccessFile oSavedFile; >}7Ml  
long nPos; '
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public FileAccessI() throws IOException c>b!{e@*  
{ ,wYA_1$$H  
this("",0); BN>t"9XpW  
} ABaK60.O[O  
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)Vf!U"  
public FileAccessI(String sName,long nPos) throws IOException G4;5$YGG  
{ a\l?7Jr  
oSavedFile = new RandomAccessFile(sName,"rw"); e0z(l/UB  
this.nPos = nPos; 1=@csO_yn  
oSavedFile.seek(nPos); $*')Sma  
} I6e[K(7NY  
b2r]>*Vc  
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public synchronized int write(byte[] b,int nStart,int nLen) Rp0`%}2 o  
{ ascY E  
int n = -1; ,j!%,!n o  
try{ cp
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oSavedFile.write(b,nStart,nLen); Q8Fqf ;4  
n = nLen; <zWMTVaC  
} 1DRih>+#  
catch(IOException e) kMx^L;:n  
{ @>Bgld&vl  
e.printStackTrace ();  eQU~A9  
} SNOML7pd  
 DJJd_  
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return n; j;yKL-ycB  
} p>=i'~lQ6  
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} 6* 6 |R93  
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/* ia#8 ^z  
**SiteInfoBean.java XVfw0-O  
*/ l.Q.G<ol  
package NetFox; 8= "
01  
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public class SiteInfoBean { 6>NK2} `  
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private String sSiteURL; //Site's URL A4{p(MS5  
private String sFilePath; //Saved File's Path 8|) $;.  
private String sFileName; //Saved File's Name N?s`a;Q[=  
private int nSplitter; //Count of Splited Downloading File [/Sk+ID  
I} .9  
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public SiteInfoBean() ]|_UpP8EP  
{//nSplitter的缺省值为5 &dky_H  
//default value of nSplitter is 5 6o)RsxN eu  
this("","","",5); )#l&BV5  
} -P:o ^_)g  
eA_]%7+`  

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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mFrDV,V  
{ cd._q2  
sSiteURL= sURL; D k<NlH zp  
sFilePath = sPath; c5(4rT{(m  
sFileName = sName; rrP_7D  
this.nSplitter = nSpiltter; -q30tO.  
3}2;*:p4Y  
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} ><xJQeW  
eb>jT:  
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public String getSSiteURL() |)*9BN  
{ {,B.OM)J  
return sSiteURL; Wud-(19  
} q8!X^1F7  

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public void setSSiteURL(String value) WX* uhR  
{ 8o i{%C&-  
sSiteURL = value; VDFs
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} 1*f
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public String getSFilePath() &!F"3bD0  
{ WH_ W:  
return sFilePath; i
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} >rXDLj-e  
7.kgQ"?&  
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public void setSFilePath(String value) N u3B02D*  
{ ?vP6~$*B  
sFilePath = value; "*LQr~k~}  
} y!c<P,Lt3f  
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public String getSFileName() E[Q2ZqhgbP  
{ wGw<z[:f  
return sFileName; op($+Q  
} O7oq1JI]Y  
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public void setSFileName(String value) TVF:z_M9  
{ Vn65:" O  
sFileName = value; M(1cf(<+  
} o@L2c3?c5  
lnGg1/
  
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public int getNSplitter() S$=caZ?  
{ >Cam6LJ  
return nSplitter; udS&$/&GH  
} y&V%xE/  
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public void setNSplitter(int nCount) L d{`k  
{ &b'{3o_KN  
nSplitter = nCount; ZnBGNr  
} s"5
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} pfR~?jYzm  
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A ^t _"J  
/* @~}~;}0x  
**Utility.java L}7 TM:%  
*/ .kTOG'K\e  
package NetFox; ;ojJXH~$}  
8)>4ZNXz  
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public class Utility { y;%\w-.\  
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public Utility() J+TtM>  
{ {e1sq^>|  
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} shEAr*u  
caxOxRo\  
//线程睡眠 $pIo`F _W  
public static void sleep(int nSecond) +6x}yc:yd  
{ p,tkVedR  
try{ \E'z+0  
Thread.sleep(nSecond); 9 e|[9  
} ] &SmeTe  
catch(Exception e) k7& cc|y  
{ ]Ot=At  
e.printStackTrace (); N_G84wxx  
} a)L|kux;l  
} F2{SC?U  
=sso )/3  
//日志 1SH]$V4C  
public static void log(String sMsg) Yr\quinLL  
{ #.vp\W  
System.err.println(sMsg); E:-~SH}  
} S|T_<FCY  
w}s5=>QG%  
96S$Y~G#&  
public static void log(int sMsg) !K+hXQE1  
{ 1h#/8X  
System.err.println(sMsg); NZO86y
/  
} ac6@E4 _  
} `(DHa=s1  
mM~&mAa+Z  
JmeE}:5lpj  
/* W*?qOq {  
**TestMethod.java 3dJiu  
*/ )3O#T$h  
package NetFox; 1]Cdfj6@  
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public class TestMethod { #*%?
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{?q`9[Z  
public TestMethod() mwMu1
#  
{ ///xx/weblogic60b2_win.exe 4`ZoAr-5|  
try{ WJI}~/z;C  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); )L7[;(gQ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =$%-RX7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v V;]?  
fileFetch.start();  ^6b5}{>  
} G$luGxl[  
catch(Exception e){e.printStackTrace ();} WYP\J1sy  
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} :S}ZF$ $j%  
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public static void main(String[] args) NJmx(!Xsh  
{ vE1:;%Q  
new TestMethod(); SrGJ#K&%  
} (pHJEY  
} 0d+b<J,  
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