http断点续传简单实现（java)

/* iLgWzA  
**SiteFileFetch.java kMUjSa~\  
*/ ab6KK$s  
package NetFox; xFgY#F  
import java.io.*; BaqRAO7  
import java.net.*; ,%Dn}mWu  
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public class SiteFileFetch extends Thread { b]@^SN9  
)/Ul"QF  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 3PPN_Z  
long[] nStartPos; //开始位置 ]x?`&f8i  
long[] nEndPos; //结束位置 iFpJ/L  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 /JJU-A(  
long nFileLength; //文件长度 .%.J Q  
boolean bFirst = true; //是否第一次取文件 H:2#/1Oz>  
boolean bStop = false; //停止标志 wU+-;C5e  
File tmpFile; //文件下载的临时信息 Xji<oih  
DataOutputStream output; //输出到文件的输出流 :IvKxOv  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 3y<;fdS7  
public SiteFileFetch(SiteInfoBean bean) throws IOException Qn6'E  
{ EN'}+E 8  
siteInfoBean = bean; %,1bh  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); CB\E@u,  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); CB:G4VqOT  
if(tmpFile.exists ()) tWT@%(2~0  
{ ]gx]7  
bFirst = false; :[A>O(  
read_nPos(); `2()Vf  
} z^'3f!:3   
else %i6i.TF  
{ <XDYnWz  
nStartPos = new long[bean.getNSplitter()]; 7
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nEndPos = new long[bean.getNSplitter()]; unY+/p $  
} 2= S;<J
 
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} 86y)+h`  
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public void run() 8&t3a+8l  
{ ^~Xs
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//获得文件长度 B~xT:r  
//分割文件 FX}kH]  
//实例FileSplitterFetch U|ZYoc+](  
//启动FileSplitterFetch线程 rY yB"|  
//等待子线程返回 i-Er|u; W  
try{ c%tb6@C  
if(bFirst) V'alzw7#  
{ 8=\}#F  
nFileLength = getFileSize(); )"KKBil0  
if(nFileLength == -1) Q#M@!&  
{ _[IOPHa"  
System.err.println("File Length is not known!"); QPr29  
} ]l/ PyX  
else if(nFileLength == -2) >JVdL\3  
{ ^6g^ Q*"  
System.err.println("File is not access!"); 
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} C^QpVt-T  
else }3HN$Fwo  
{ IPHZ~'M  
for(int i=0;i<nStartPos.length;i++) MEKsL7  
{ fD:BKJQ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); oyC5M+shP9  
} GoSdo  
for(int i=0;i<nEndPos.length-1;i++) #X 1 GL  
{ J> Z.2  
nEndPos = nStartPos[i+1]; ; ,9:1.L  
} R^*%yjy9  
nEndPos[nEndPos.length-1] = nFileLength; dBRK6hFC  
} HAKB@h)  
} Rq`d I~5!b  
yX7P5c.   
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//启动子线程 1buVV]*~  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; CNMcQP  
for(int i=0;i<nStartPos.length;i++)
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{ xw
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ie"eqO!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `En>o~L;  
nStartPos,nEndPos,i); i U"2uLgb  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); vCX
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fileSplitterFetch.start(); o$q})!  
} h[(.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5do49H_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); i&mt-  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", K3dg.>O  
nEndPos = " + nFileLength); (/$a*$  
// fileSplitterFetch[nPos.length-1].start(); C.`!?CW  
|\BxKwS^  
\DMZ 
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//等待子线程结束 G0h/]%I  
//int count = 0; .dPy<6E  
//是否结束while循环 Fa+#bX7  
boolean breakWhile = false; L)"E_  
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while(!bStop) p N+1/m,  
{ Mwtd<7<!A  
write_nPos(); H:
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Utility.sleep(500); zvOSQxGQ  
breakWhile = true; hqc)Ydg_%  
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for(int i=0;i<nStartPos.length;i++) :{=2ih-}  
{ Q@ghQGn#  
if(!fileSplitterFetch.bDownOver) vYNu=vnM  
{ 6~+/cY-V  
breakWhile = false;  WfH4*e  
break; D` abVf  
} d)1Pl3+  
} v=J[p;H^H  
if(breakWhile) ,M0#?j>  
break; krecUpo  
/SKgN{tWe  
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//count++; Yq0jw&v  
//if(count>4) VRA0p[  
// siteStop(); k:DAko}  
} O Ce;8^  
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System.err.println("文件下载结束！"); 9-hVlQ~|  
} bR}=bp4K  
catch(Exception e){e.printStackTrace ();} &Ef_p-e-P  
} /2Qgg`^)  
!9g>/9h  
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//获得文件长度 9
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public long getFileSize() gaVQ3NqF  
{ R}0xWPt9G  
int nFileLength = -1; !A=>B=.|D  
try{ 0Q5fX}  
URL url = new URL(siteInfoBean.getSSiteURL()); s^>1rV]=(`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M2rgB%W)m  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~O~R,h>  
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int responseCode=httpConnection.getResponseCode(); W8Aii'Q8C/  
if(responseCode>=400) ,%U'>F?  
{ 69JC!du  
processErrorCode(responseCode); sHf.xc  
return -2; //-2 represent access is error =plU3D2  
} jCxg)D7W  
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String sHeader; B^lm'/,@  
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for(int i=1;;i++) +X4/l"|  
{ +/Qgl  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Jwe9L^gL  
//Utility.log(in.readLine()); ?n9?`8a#  
sHeader=httpConnection.getHeaderFieldKey(i); d!#qBn$*[  
if(sHeader!=null) p}9bZKyf  
{ 6rg?0\A<  
if(sHeader.equals("Content-Length")) /d-
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{  >q^l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >Qold7 M  
break; %eQw\o,a  
} WbH#@]+DN  
} ;=F]{w]$+  
else ,{VC(/d  
break; >Z&Y!w'A|u  
} <
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} \A=:6R%Qb  
catch(IOException e){e.printStackTrace ();} ?JI:>3e  
catch(Exception e){e.printStackTrace ();} #t?tt,nc}  
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Utility.log(nFileLength); F2
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return nFileLength; t-3y`31i.  
} 8oVQ:' 6  
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//保存下载信息（文件指针位置） ,+hH|$  
private void write_nPos() B?p18u$i#l  
{ G~fM!F0   
try{ Z+]Uw  
output = new DataOutputStream(new FileOutputStream(tmpFile)); c037#&Q%#  
output.writeInt(nStartPos.length); J8:f9a:|M  
for(int i=0;i<nStartPos.length;i++) E|>oseR  
{ ,sln0  
// output.writeLong(nPos); R1lC_G]  
output.writeLong(fileSplitterFetch.nStartPos); Q{"QpVY8  
output.writeLong(fileSplitterFetch.nEndPos); }vspjplk^  
} ?O.1HEr  
output.close(); 'I8K1Q=/  
} I|oS`iLl$  
catch(IOException e){e.printStackTrace ();} rj> _L  
catch(Exception e){e.printStackTrace ();} Vp~c$y+  
} ?OFl9%\ V  
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//读取保存的下载信息（文件指针位置） TqN4OkCm/  
private void read_nPos() @Wb_Sz4`  
{ e )?~  
try{ !Ey=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g&oAa;~o  
int nCount = input.readInt(); UoSzxL  
nStartPos = new long[nCount]; "0edk"hk  
nEndPos = new long[nCount]; 1YxG<K]  
for(int i=0;i<nStartPos.length;i++) y_e$W3bON,  
{ t/`~(0F  
nStartPos = input.readLong(); cN(Toj'`  
nEndPos = input.readLong(); )%T<Mw2u  
} h.ln%6:d  
input.close(); ]1k"'XG4,  
} MR{JMo=r  
catch(IOException e){e.printStackTrace ();} ,9@JBV%_  
catch(Exception e){e.printStackTrace ();} WXzSf.8p|  
} HX&G  k  
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private void processErrorCode(int nErrorCode) q*E<~!jL  
{ ]:X# w0UR  
System.err.println("Error Code : " + nErrorCode); `HO_t ek  
} zA g.,dA  
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K
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//停止文件下载 uz%<K(:Ov  
public void siteStop() ZD(VH6<g%  
{ RL|d-A+;  
bStop = true; yur5"$n  
for(int i=0;i<nStartPos.length;i++) XHER[8
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fileSplitterFetch.splitterStop(); d)yu`U  
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s  
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} `EJ.L6j$'  
} (O@fgBM  
//负责部分文件的抓取 (<ZpT%2  
**FileSplitterFetch.java "AcC\iq  
*/ Am @o}EC  
package NetFox; L)qDtXd4  
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import java.io.*; j2GTo~muq  
import java.net.*; r\."=l  
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public class FileSplitterFetch extends Thread { FBP'AL|  
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String sURL; //File URL .X](B~\!  
long nStartPos; //File Snippet Start Position FD[o94`%  
long nEndPos; //File Snippet End Position \Aq$h:<  
int nThreadID; //Thread's ID fuQk}OW{  
boolean bDownOver = false; //Downing is over L4t(Y7  
boolean bStop = false; //Stop identical h7a/]~  
FileAccessI fileAccessI = null; //File Access interface WZ6'"Cz`  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException r"&uW!~0  
{ bHK[Z5  
this.sURL = sURL; h2P&<ggqX  
this.nStartPos = nStart; F"| ;  
this.nEndPos = nEnd; ?[#4WH-G  
nThreadID = id; K3.z>.F'h  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 '(fzznRH  
} ~oX`Gih  
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public void run() U_C[9Z'P  
{ 9 K~X+N\  
while(nStartPos < nEndPos && !bStop) 044Q>Qz,  
{ @QfbIP9  
-_^#7]  
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try{ U7xKu75G1  
URL url = new URL(sURL); f7?u`
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t3<HE_B|  
httpConnection.setRequestProperty("User-Agent","NetFox"); /:ju/~R}  
String sProperty = "bytes="+nStartPos+"-"; U&o~U] rm  
httpConnection.setRequestProperty("RANGE",sProperty); ?W\KIp\Kn  
Utility.log(sProperty); 5;CqGzgoP  
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InputStream input = httpConnection.getInputStream(); l(Y\@@t1  
//logResponseHead(httpConnection); *],=!  
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byte[] b = new byte[1024]; ^0(`:*  
int nRead; rI'kZ0&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +HF*X~},i  
{ :a*F>S!  
nStartPos += fileAccessI.write(b,0,nRead); S #C;"se  
//if(nThreadID == 1) ,!bcm  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SN5Z@kK  
} !|-:"hE1h  
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Utility.log("Thread " + nThreadID + " is over!"); $%zM Z  
bDownOver = true; 97n,^t2F\  
//nPos = fileAccessI.write (b,0,nRead); Q5c13g2
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} ^)1!TewCY  
catch(Exception e){e.printStackTrace ();} 1i 7p'  
} bJB*
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} A&`7 l5~X  
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//打印回应的头信息 I{7Hz{  
public void logResponseHead(HttpURLConnection con) $*;ke5Dm4  
{ g.x]x#BC  
for(int i=1;;i++) Ql9 )  
{ | (: PX  
String header=con.getHeaderFieldKey(i); '_%`0p1  
if(header!=null) E|ZLz~  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ew2ksZ>B]&  
Utility.log(header+" : "+con.getHeaderField(header)); u<nPJeE  
else D1~3 3;  
break;
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} 4fau 9bW  
} 9 [wR/8Xm  
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public void splitterStop() ?q hme   
{ 0BQ<a  
bStop = true; Q);^gV  
} r&D&xsbQ  
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} :a y-2  
S1W(]%0/  
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/* )Tj\ym-Vl  
**FileAccess.java `"<tk1Kq"  
*//文件访问(定位，写) H
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package NetFox; 4&^BcWqA*f  
import java.io.*; TkV*^j5
 
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public class FileAccessI implements Serializable{ or..e  
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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 d=8q/]_p  
RandomAccessFile oSavedFile; o;2QZ"v  
long nPos; #F!'B|n  
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public FileAccessI() throws IOException KsBi<wY  
{ K\`>'C2_V  
this("",0); H}B%OFI\+  
} -VlXZj@u+  
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public FileAccessI(String sName,long nPos) throws IOException Ff@Cs0R  
{ dSm; e_s  
oSavedFile = new RandomAccessFile(sName,"rw"); +$H`/^a.  
this.nPos = nPos; Zqnwf  
oSavedFile.seek(nPos); {expx<+4F  
} l gzA) (  
c})f&Z@<  
mh=YrDU+L  
public synchronized int write(byte[] b,int nStart,int nLen) _r&,n\ T  
{ q:/<^|  
int n = -1; Xv'5%o^i*  
try{ o0'!u  
oSavedFile.write(b,nStart,nLen); yq2pg8%  
n = nLen; !+# pGSk  
} ).b,KSi  
catch(IOException e) EFNi# D8s  
{ l4+Bs!i`  
e.printStackTrace (); nVt,= ?_ U  
} a{FCg%vD)  
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return n; z nxAP|  
} swh8-_[c/  
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} C>:'@o Z  
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%!X|X
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/* qXw^y  
**SiteInfoBean.java iYk4=l  
*/ OmR)W'  
package NetFox; yxx'g+D*  
\6)]!$F6:  
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public class SiteInfoBean { 6SGV}dAx  
+xc1cki_{  
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private String sSiteURL; //Site's URL _vV3A3|Ec,  
private String sFilePath; //Saved File's Path Oe["4C  
private String sFileName; //Saved File's Name 4fyds< f  
private int nSplitter; //Count of Splited Downloading File p9`!.~[  
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._i|+[  
public SiteInfoBean() c&GVIrJ  
{//nSplitter的缺省值为5 !Enq2  
//default value of nSplitter is 5 nde_%d$  
this("","","",5); O8Dav^\y?  
} #{DX*;1
m  
-$2a@K,i  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) MoX~ZewWR  
{ .;$Ub[
  
sSiteURL= sURL; 9k.5'#  
sFilePath = sPath; ^kO+NH40  
sFileName = sName; A 6IrA/b  
this.nSplitter = nSpiltter; !K[UJQs\  
?-Zl(uX  
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} $&~moAl  
6
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public String getSSiteURL() >2t.7UhDI  
{ ?l9j]  
return sSiteURL; 90[6PSXk  
} h4#y'E!,Z  
1p5n}|  
2Wn*J[5  
public void setSSiteURL(String value) !*1$j7`tP  
{ .mbqsb]&Y  
sSiteURL = value; omMOA  
} 9$?Sts}6&  
3%[;nhbA7  
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public String getSFilePath() J6I:UML  
{ T!7B0_  
return sFilePath; ,r8#-~A6,A  
} ;aN_!! r  
I
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public void setSFilePath(String value) nSv@FT'~z  
{ jQrj3*V  
sFilePath = value; vh#81}@N7*  
} >t_h/:JZ)  

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public String getSFileName() 'eo/"~/*w  
{ xG(xG%J  
return sFileName; ,gpZz$Ef(  
} v YJ9G"E  
BW:HKH.k  
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public void setSFileName(String value) )qRH?Hsb7  
{ ]h?q1   
sFileName = value; 5-hnk' ~  
} zM,r0Z  
p|C[
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public int getNSplitter() : eCeJ~&E  
{ E<jW;trt_  
return nSplitter; yQ)&u+r  
} h 8xcq#  
VsJiE0'%  
z2>LjM) #  
public void setNSplitter(int nCount) q;}iW:r&Q  
{ gBky
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nSplitter = nCount; f14^VTzP/#  
} Z5E; FGPb  
} 2Rt6)hgY  
t/}NX[q  
F"bz<{  
/* q)mG6Su d  
**Utility.java a'-u(Bw  
*/ |UlG@Mn  
package NetFox; $~S~pvT  
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public class Utility { gW,hI>  
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public Utility() l>MDCqV  
{ \ )=WA!  
@)BO`;*$fF  
>MGWN  
} x9,jXd  
}DXG;L  
//线程睡眠 )q[P&f(h  
public static void sleep(int nSecond) i84!x%|P  
{ xZP*%yM  
try{ &iInru3  
Thread.sleep(nSecond); 1_<x%>zG  
} h~m,0nGO  
catch(Exception e) ":_II[FPY  
{ ?+))J~@t  
e.printStackTrace (); 00.x*v  
} a3>/B$pE  
}
8[KKi~A  
8f/KNh7#s  
//日志 [Q0V5P~Q'  
public static void log(String sMsg) >;^/B R=  
{ Lxwi"ndP  
System.err.println(sMsg); c3O/#*  
} N^dQX,j  
{YgU23;q  
{2h*NFp  
public static void log(int sMsg) bAPMD  
{ w.-x2Zg},  
System.err.println(sMsg); =nGFLH6)  
} Ln4]uqMG.  
} 7ocUFY0"  
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/* 393c |8M  
**TestMethod.java hO]F\0+  
*/ E ?Mgbd3  
package NetFox; B;r_[^  
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public class TestMethod { PjeI&@  
orFwy!  
ZC N}iQu4  
public TestMethod() 8YFG*HSa  
{ ///xx/weblogic60b2_win.exe XI\Slq  
try{ -N*[f9EJB  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); u%~'+=  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 
Z 2N6r6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 509T?\r  
fileFetch.start(); `eMZhYo  
} ENZym
  
catch(Exception e){e.printStackTrace ();} uu.X>agg  
cXPpxRXBD  
/_0B5,6R  
} x95s%29RS  
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= LNU%0m  
public static void main(String[] args) a;xeHbE
 
{ I=kqkuW  
new TestMethod(); #<xFO^TB  
} ~#E&E%s
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} x4I!f)8Q
 
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