http断点续传简单实现（java)

/* la{Iqm{i  
**SiteFileFetch.java 1vUW$)?X  
*/ }&Kl)2:O  
package NetFox; rJUXIV>z  
import java.io.*; vD3j(d  
import java.net.*; SU>cJ*  
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public class SiteFileFetch extends Thread { Pt[ b;}  
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SiteInfoBean siteInfoBean = null; //文件信息Bean s8|Fe_  
long[] nStartPos; //开始位置 @8"c
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long[] nEndPos; //结束位置 (c|Ry[$|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 =L9;8THY  
long nFileLength; //文件长度 f0]`TjY  
boolean bFirst = true; //是否第一次取文件 r0j+P%  
boolean bStop = false; //停止标志 ' T%70)CM~  
File tmpFile; //文件下载的临时信息 Ot
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DataOutputStream output; //输出到文件的输出流 $i;_yTht  
x A"V!8C  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )Oix$B!-  
public SiteFileFetch(SiteInfoBean bean) throws IOException D9;s%  
{ bXRSKp[$  
siteInfoBean = bean; GjeRp|_Qd<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); VK3e(7b  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Yu_` >so  
if(tmpFile.exists ()) rO7[{<97m  
{ i8i~b8r]  
bFirst = false; O~&j}WN  
read_nPos(); _ Y8jl,J  
} J*m~fZ^  
else 8c5%~}kG  
{ R~H+.Vh  
nStartPos = new long[bean.getNSplitter()]; \Ws$@J-M  
nEndPos = new long[bean.getNSplitter()]; -$tf`   
} WNWtQ2]  
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} &.)ST0b4  
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public void run() z%44@TP  
{ xay~
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//获得文件长度 Ae|bAyAK  
//分割文件 j,CVkA*DY  
//实例FileSplitterFetch ^Kfm(E  
//启动FileSplitterFetch线程 7]lUPLsl  
//等待子线程返回 Zil<*(kv{  
try{ vd#BT$d?  
if(bFirst) `|f1^C^  
{ $.T\dm
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nFileLength = getFileSize(); }CB9H$FkCY  
if(nFileLength == -1) |P(8T'  
{ k btQ  
System.err.println("File Length is not known!"); )F65sV{  
}
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else if(nFileLength == -2) s]Qo'q
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{ S/
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System.err.println("File is not access!"); =sh
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} ~xU\%@I\  
else m`6=6(_p  
{
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for(int i=0;i<nStartPos.length;i++) rkWiGiisM  
{ :3.!?mOe2  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 'NSfGC%7R  
} [kL`'yi  
for(int i=0;i<nEndPos.length-1;i++) ;I!Vba  
{ C
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nEndPos = nStartPos[i+1]; 9Je+|+s]  
} h$$2(!G4  
nEndPos[nEndPos.length-1] = nFileLength; H rI(uZ]  
} lCiRvh1K  
} e(Y5OTus  
a}5/?/  
&"mWi-Mpl  
//启动子线程 ~R C\  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; )bl^:C  
for(int i=0;i<nStartPos.length;i++) "eZ~]m}L0  
{ UB3hC`N\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \CVrLn;}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c%5Suu(J6  
nStartPos,nEndPos,i); /[,0,B9!3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pv@w 8*  
fileSplitterFetch.start(); k4`(7Z  
} @ *n oma  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,^@z;xF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /f]'_t0\.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )8 %lZ{  
nEndPos = " + nFileLength); !T$h?o  
// fileSplitterFetch[nPos.length-1].start(); @:K={AIa  
$64sf?aZ>#  

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//等待子线程结束 
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//int count = 0; 2g$;ZBHO|8  
//是否结束while循环 xy+hrbD)j  
boolean breakWhile = false; Uj twOv|pF  
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while(!bStop) p"d_+  
{ dlCmSCp%  
write_nPos(); ~
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Utility.sleep(500); >\'gIIs  
breakWhile = true; U)] }EgpF  
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for(int i=0;i<nStartPos.length;i++) A1F!I4p5  
{ k293
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if(!fileSplitterFetch.bDownOver) $<F9;Z  
{ I T gzD"d  
breakWhile = false; m\@q2l-  
break; .RN2os{  
} L&G5 kY`  
} WuMr";2*E  
if(breakWhile) `P?!2\/  
break; R/Te;z  
k]~|!`  
37 d-!  
//count++; + ;_0:+//  
//if(count>4) 7O<K?;I  
// siteStop(); OEhDRU%k  
} b{a\j
%  
>8%O;3-m#  
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System.err.println("文件下载结束！"); Uu~~-5  
} As>P(  
catch(Exception e){e.printStackTrace ();} Aga{EKd  
} h=ben&m  

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//获得文件长度 i^}ib RQbN  
public long getFileSize() "Zu>cbE  
{ Hgbrlh  
int nFileLength = -1; 9@wmngvM*Y  
try{ {;+9A}e  
URL url = new URL(siteInfoBean.getSSiteURL()); /dwj:g0y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >(C5&3^  
httpConnection.setRequestProperty("User-Agent","NetFox"); H&uh$y@  
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int responseCode=httpConnection.getResponseCode(); T0"q,lrdxV  
if(responseCode>=400) Bj
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{  |Fe*t  
processErrorCode(responseCode); Huf;A1.  
return -2; //-2 represent access is error :ioD*k  
} AYv7-!Yk  
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String sHeader; `qhZZ{s)1U  
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for(int i=1;;i++) w:/QB-`%  
{ 2-beq<I  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());
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//Utility.log(in.readLine()); yeIcQ%  
sHeader=httpConnection.getHeaderFieldKey(i); li9>zjz  
if(sHeader!=null)
S)x5.vo^  
{ MR/gLm(8(  
if(sHeader.equals("Content-Length")) XvIY=~  
{ PH>`//D%n?  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ny G?^  
break; $PFE>=nM  
} \CrWKBL  
} =`.OKUAn  
else wW|[Im&  
break; ZiC~8p
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} 2<tU  
} cBQ+`DXn5c  
catch(IOException e){e.printStackTrace ();} \-CL}Z}S  
catch(Exception e){e.printStackTrace ();} H0-v^H>^  
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Utility.log(nFileLength); WB3YN+Xl3  
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return nFileLength; *Qy,?2  
} aRcVoOq  
0gH;y+\=*  
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//保存下载信息（文件指针位置） Y?\PU{O  
private void write_nPos() UnOcw  
{ *H~&hs>k  
try{ 3M5wF6nY[[  
output = new DataOutputStream(new FileOutputStream(tmpFile));  I}u&iV`  
output.writeInt(nStartPos.length); qkBCI,X_Y  
for(int i=0;i<nStartPos.length;i++) GuKiNYI_  
{ U &
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// output.writeLong(nPos); J }|6m9k!  
output.writeLong(fileSplitterFetch.nStartPos); i=jYl  
output.writeLong(fileSplitterFetch.nEndPos); @.} @K  
} R
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output.close(); t^"8 v3
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} Zty9O8g  
catch(IOException e){e.printStackTrace ();} 23/;W|   
catch(Exception e){e.printStackTrace ();} naVbcY  
} HM
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3|=L1Pw#  
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//读取保存的下载信息（文件指针位置） i!yE#z
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private void read_nPos() G$VE o8Blb  
{ sf8F h  
try{ 6Cgc-KNbk  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .q|k459oi  
int nCount = input.readInt();  NR98]X  
nStartPos = new long[nCount]; :H>0/^Mg0  
nEndPos = new long[nCount]; w+iIay  
for(int i=0;i<nStartPos.length;i++) a;=IOQ  
{  bU$M)  
nStartPos = input.readLong(); gjn1ha"h%.  
nEndPos = input.readLong(); }ZJJqJ`*e  
} .p(%gmOp#  
input.close(); ei(S&u<  
} yaYJmhG  
catch(IOException e){e.printStackTrace ();} =Y5_@}\0  
catch(Exception e){e.printStackTrace ();} CTJwZY7  
} mX[J15  
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private void processErrorCode(int nErrorCode) 1 Q*AQYVY  
{ JC iB;!y  
System.err.println("Error Code : " + nErrorCode); fndbGbl8p  
} RaOLy \  
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wY"BPl]b  
//停止文件下载 Y6m:d&p=}  
public void siteStop() /xCX. C  
{ P DwBSj  
bStop = true; jmF)iDvjuZ  
for(int i=0;i<nStartPos.length;i++) PxA OKUpI  
fileSplitterFetch.splitterStop(); +#9 4X)*  
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} 1AQy8n*  
} ?{\h`+A  
//负责部分文件的抓取 }WHq?  
**FileSplitterFetch.java r9n:[A&HE  
*/ -Eoq#ULvR  
package NetFox; L| ;WE=  
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import java.io.*; *z&hXYm  
import java.net.*; +*wr=9>  
t&~*!w!+jH  
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public class FileSplitterFetch extends Thread { 8khIy-9-'  
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}^2'@y!(  
String sURL; //File URL onl,R{,`0  
long nStartPos; //File Snippet Start Position Z29aRi  
long nEndPos; //File Snippet End Position B`:l;<&jX  
int nThreadID; //Thread's ID f o idneus  
boolean bDownOver = false; //Downing is over TQth"Cv2:  
boolean bStop = false; //Stop identical ]q/USVj{  
FileAccessI fileAccessI = null; //File Access interface O=oIkvg  
. f!dH  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 51xf.iB  
{ |)S*RQb\  
this.sURL = sURL; .R)uk  
this.nStartPos = nStart; 51;[R8'w  
this.nEndPos = nEnd; a\}` f=T  
nThreadID = id; *Tr9pq%m  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B+MnT{  
} KxDp+]N]  
AWd,qldv  
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public void run() nPk&/H%5hn  
{ +'wO:E1( w  
while(nStartPos < nEndPos && !bStop) `><E J'h  
{ &0]5zQ  
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try{ }i J$&CJ  
URL url = new URL(sURL); tVh"C%Vkr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ] !n3j=*  
httpConnection.setRequestProperty("User-Agent","NetFox"); Pbt7T Q  
String sProperty = "bytes="+nStartPos+"-"; IyAD>Q^  
httpConnection.setRequestProperty("RANGE",sProperty); A9MTAm{  
Utility.log(sProperty); :*s@L2D6  
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InputStream input = httpConnection.getInputStream(); -b|"%e<'  
//logResponseHead(httpConnection); R2JPLvs  
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byte[] b = new byte[1024]; w~yC^`  
int nRead; zbgGK7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]E6r)C  
{ x"r,l/gzy  
nStartPos += fileAccessI.write(b,0,nRead); k8r1)B4ab  
//if(nThreadID == 1) wN

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// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j4u ["O3  
} M3r;Pdj2r  
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Utility.log("Thread " + nThreadID + " is over!"); mtdy@=?1Y  
bDownOver = true; rAE5.Q!u  
//nPos = fileAccessI.write (b,0,nRead); |a%Wd  
} hzT)5'_  
catch(Exception e){e.printStackTrace ();} F|@\IVEB]  
} Wg20H23XW  
} '.C#"nY>1  
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//打印回应的头信息 $Ggnn#  
public void logResponseHead(HttpURLConnection con) RC?vU  
{ nLx|$=W  
for(int i=1;;i++) 6OoOkN
WF  
{ 6b9J3~d\E  
String header=con.getHeaderFieldKey(i); a$Hq<~46  
if(header!=null) ~+ 9vz  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); *eX/ZCn  
Utility.log(header+" : "+con.getHeaderField(header)); M&)\PbMc  
else _EJPI  
break; 3_`)QYU'  
} \0vs93>?  
} jAU&h@  
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public void splitterStop() IUNr<w<  
{ "YWZ&_n**  
bStop = true; .rS. >d^n  
} vn!3Z!dm(  
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} jOzi89  
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/* 1z4_QZZ.NG  
**FileAccess.java -y{(h%6  
*//文件访问(定位，写) 'GT^araz  
package NetFox; '#=0q  
import java.io.*; %V+"i_{m  
:HwdXhA6  
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public class FileAccessI implements Serializable{ )(_NFp
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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 esj6=Gh  
RandomAccessFile oSavedFile; 2pU'&8  
long nPos; DR,7rT{$  
'#h ORQB  
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public FileAccessI() throws IOException ,II3b(l  
{ LrT EF j  
this("",0); \P")Eh =d  
} V)l:fUm2  
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public FileAccessI(String sName,long nPos) throws IOException &9|L Z9K  
{ S[zGA<}  
oSavedFile = new RandomAccessFile(sName,"rw"); d4*SfzB  
this.nPos = nPos; ' QMcQvU  
oSavedFile.seek(nPos); u&^KrOM@#  
}
'&dT  
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public synchronized int write(byte[] b,int nStart,int nLen) N-_APWA  
{ K&Bbjb_|  
int n = -1; Em^~OM3U$q  
try{ M=lU`Sm  
oSavedFile.write(b,nStart,nLen); d~QM@<SV  
n = nLen; w;j<$<4=7  
} >TY;l3ew  
catch(IOException e) _U-`/r o  
{ 9}m?E<6&  
e.printStackTrace (); GBT|1c'i  
} !|UX4  
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return n; cz{`'VN}`  
} {\CWoFht>  
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} 6h2keyod  
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/* >}%#s`3W1_  
**SiteInfoBean.java
AvB=/p@]  
*/ IZ7o6Etti  
package NetFox; _+NjfF|  
2#sFY/@  
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public class SiteInfoBean { $ P5K  
 Pd\4hy  
Fa[^D~$l*  
private String sSiteURL; //Site's URL )Uy%iE*  
private String sFilePath; //Saved File's Path !Q15qvRS  
private String sFileName; //Saved File's Name *DC/O( 0  
private int nSplitter; //Count of Splited Downloading File ]& ckq  
lnHY?y7{  
peBHZJ``RX  
public SiteInfoBean() #qYgQ<TM!  
{//nSplitter的缺省值为5 PA ?2K4  
//default value of nSplitter is 5 HI 1T  
this("","","",5); 7Q9Hk(Z9  
} OKlR`Vaty  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) A,~KrRd  
{ nJ]7vj,rB  
sSiteURL= sURL; 4 ZnQpKg  
sFilePath = sPath; WA~[)S0
  
sFileName = sName; $wp>2  
this.nSplitter = nSpiltter; )9_W"'V  
xc 1d[dCdp  
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} 3*~`z9-z  
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public String getSSiteURL() $f0u  
{ {VW\EOPV~  
return sSiteURL; 2HmK['(  
} ch]Q
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public void setSSiteURL(String value) i0K 2#}=^  
{ PdqvXc  
sSiteURL = value; ?Y3i-jY
  
} Zf3(! a[  
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public String getSFilePath() e'A_4;~@s  
{ BInSS*L  
return sFilePath; Lv['/!DJ|  
} * @]wT'  
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public void setSFilePath(String value) (WC =om  
{ [mu8V+8@d4  
sFilePath = value; #$xtUCqX  
} slPr^)  
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P
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public String getSFileName() }6\,kFc  
{ ?V8Fgd  
return sFileName; X
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} 4"kc(J`c  
v77UE"4|c  
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public void setSFileName(String value) Rf8Obk<  
{ `WOoC  
sFileName = value; ftTD-d  
} jn|NrvrX  
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public int getNSplitter() \ Y
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{ 4;J.$  
return nSplitter; >~Zj  
}
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public void setNSplitter(int nCount) 8xAIn>,_  
{ oQ r.cKD ?  
nSplitter = nCount; STjb2t,a  
} %C,zR&]F  
} A?#i{R  
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9nc_$H{  
/* .:}<4;Qz94  
**Utility.java [;,E cw^  
*/ fVgK6?<8^  
package NetFox; }Y.YJXum  
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*W\3cS  
public class Utility { qfl!>  
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public Utility() 'uL$j
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{ yg'CL/P  
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} "KK}}$>  
,H"}Rw
 
//线程睡眠 1q!k#Cliu  
public static void sleep(int nSecond) 1
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{ J' P:SC1  
try{ k 6[   
Thread.sleep(nSecond); e
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} d^RcJ3w  
catch(Exception e) HN N
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{ ? bWc<]  
e.printStackTrace (); k8}fKVU;  
} ASoBa&vX  
} p1niS:}j  
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//日志 ZrEou}z(*  
public static void log(String sMsg) 153*b^iDBh  
{ 1
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System.err.println(sMsg); A,EG0yb  
} 8Gy]nD  
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h )Y.jY  
public static void log(int sMsg) y
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{ TDR|*Cs  
System.err.println(sMsg); Q3l>xh  
} |+Rx)  
} v1yB  
[C4{C4TX  
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/* 8BAe6-*S8  
**TestMethod.java s-Gd{=%/q  
*/ ;q9Y%*  
package NetFox; {= &&J@:  
-FZNk}  
1VFCK&  
public class TestMethod { #]c
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F-:AT$Ok  
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public TestMethod() TxQsi"0c  
{ ///xx/weblogic60b2_win.exe SHPDbBS  
try{ X1B)(|7$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); }o!b3*#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); WP\kg\o  
SiteFileFetch fileFetch = new SiteFileFetch(bean); j7g>r/1eE  
fileFetch.start(); \kyoA Z  
} bz nMD  
catch(Exception e){e.printStackTrace ();} \Kui`X  
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} *^[6uaa
 
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>?JUGXAi'{  
public static void main(String[] args) )UU`uzU;u  
{ B=W#eu <1  
new TestMethod(); 3'L =S  
} :dipk,b?n  
} mm#UaEp  
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