http断点续传简单实现（java)

/* r~)VGdB+  
**SiteFileFetch.java *Jb_=
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*/ .=Pm>o/,  
package NetFox; UUl*f!&
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import java.io.*; j
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import java.net.*; &nQRa?3,   
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public class SiteFileFetch extends Thread { 4$%`Qh>yA  
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 pz$_W  
SiteInfoBean siteInfoBean = null; //文件信息Bean -{!&/;Z  
long[] nStartPos; //开始位置 :tKbz nd/  
long[] nEndPos; //结束位置 ZR1+ O8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 L<0=giE  
long nFileLength; //文件长度 w3<Z?lj:  
boolean bFirst = true; //是否第一次取文件 9U]pH%.9  
boolean bStop = false; //停止标志 a|UqeNI{  
File tmpFile; //文件下载的临时信息 r k@UsHy  
DataOutputStream output; //输出到文件的输出流 -dl}_   
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ?^U c=  
public SiteFileFetch(SiteInfoBean bean) throws IOException BApa^j\?  
{ `Gf{z%/  
siteInfoBean = bean; SLSF
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); y0;,dv]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");
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if(tmpFile.exists ()) *0O<bm  
{ >5c]
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bFirst = false; #De(*&y2  
read_nPos(); JdtPY~k0  
} -eUV`&[4  
else NzAQ@E2d:  
{ Hr8\QgD<4  
nStartPos = new long[bean.getNSplitter()]; /;DjJpwf0  
nEndPos = new long[bean.getNSplitter()]; ^,Xa IP+[  
} 60'6/3  
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} p[u4,  
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public void run() EVG"._I@  
{ Axf^
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//获得文件长度 l7ZB3'  
//分割文件 (JWv *p  
//实例FileSplitterFetch Q2q|*EL  
//启动FileSplitterFetch线程 Eevw*;$x  
//等待子线程返回 1XCmMZ  
try{ L+73aN  
if(bFirst) z=B< `}@3  
{ 3i6h"Wu`n  
nFileLength = getFileSize(); \OP9_J(*  
if(nFileLength == -1)
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{ 'v\j.j/i  
System.err.println("File Length is not known!"); W
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} .`Sw,XL5  
else if(nFileLength == -2) +mi
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{ ANotUty;y  
System.err.println("File is not access!"); u-kZW1wrQ  
} ~*,Wj?~+7  
else ><X $#  
{ w m19T7*L  
for(int i=0;i<nStartPos.length;i++) mdaYYD=c%  
{ # J]~  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <iRWd  
} X3AwM%,!  
for(int i=0;i<nEndPos.length-1;i++) zLL)VFCJW  
{ b) Ux3PB  
nEndPos = nStartPos[i+1]; ~ibF M5m  
} of=ql  
nEndPos[nEndPos.length-1] = nFileLength; vffH  
} "(<%Ua  
} @O'I)(To  
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w?_`/oqd|  
//启动子线程 OMvT;Vgg  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; } #qQ2NCH  
for(int i=0;i<nStartPos.length;i++) $.9 +{mz  
{ '<W<B!HP5Z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !x8kB Di,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), L$SMfx  
nStartPos,nEndPos,i); T!(sZf  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T
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fileSplitterFetch.start(); [T-*/}4$  
} ?]5Ix1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (V!0'9c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); PGkCOmq   
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5~QTg  
nEndPos = " + nFileLength); 1)'Iu`k/  
// fileSplitterFetch[nPos.length-1].start(); [EER4@_  
7/ t:YBR  
{<!hlB  
//等待子线程结束 %P;[fJ `G  
//int count = 0; QAi1,+y]7w  
//是否结束while循环 u3ST;  
boolean breakWhile = false; L@?e:*h  
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1U'ZVJ5bpK  
while(!bStop) fq=:h\\G  
{ \qB6TiB/  
write_nPos(); ~@@ Z|w  
Utility.sleep(500); W6i3Psjsw  
breakWhile = true; 6`Lc
s
  
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for(int i=0;i<nStartPos.length;i++) Bh,Q8%\6  
{ vbaC+AiX  
if(!fileSplitterFetch.bDownOver) oBC]UL;8xJ  
{ s*.3ZS5  
breakWhile = false; z>p]/Sa  
break; ++0rF\&  
} )T/J  
} Zt_r9xs>  
if(breakWhile) &}E:jt}  
break; 2qjyFTT  
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S2Vxe@b)  
//count++; 14-]esSa  
//if(count>4) ]);NnsG  
// siteStop(); p(?g-
  
} {"t5\U6cKM  
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System.err.println("文件下载结束！"); zIm-X,~I$  
} h;nQxmJ9  
catch(Exception e){e.printStackTrace ();} iu|v9+  
} #2N_/J(U  
x9D/s`!  
fK"iF@=Z`  
//获得文件长度 r>O|L%xpv  
public long getFileSize() @h9K  
{ %N1"*</q  
int nFileLength = -1; }^ ,q#'  
try{ G AEZY

 
URL url = new URL(siteInfoBean.getSSiteURL()); 1mix+.d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _*n)mlLln  
httpConnection.setRequestProperty("User-Agent","NetFox"); V:>`*tlh  
D J_DonO]  
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int responseCode=httpConnection.getResponseCode(); NNp}|a9  
if(responseCode>=400) *:
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{ gyFr"9';c  
processErrorCode(responseCode); A_F0\ EN*  
return -2; //-2 represent access is error uJ8x  
} B\0t&dai|'  
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 P63 (^R  
String sHeader; 2LZS|fB9o  
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for(int i=1;;i++) v2=/[E@  
{ Fv@tD4I>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); AK;^9b-}q:  
//Utility.log(in.readLine()); yzg9I  
sHeader=httpConnection.getHeaderFieldKey(i); 0Z8/R  
if(sHeader!=null) Q1]Wo9j  
{ [zx|eG<&-  
if(sHeader.equals("Content-Length")) oLw|uU-
|  
{ @ t|3gF$X  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));  J `x}{K  
break; yKlU6t&` G  
} qy&\Xgn;GA  
} ~QCA -Yud  
else eo ?Oir)  
break; vcM~i^24)  
} 9t0Cj/w}  
} x G^f  
catch(IOException e){e.printStackTrace ();} xG w?'\  
catch(Exception e){e.printStackTrace ();} F1J#Y$q~L  
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Utility.log(nFileLength); U3+A MVnB  
+ ~~ Z0.[  
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return nFileLength; W}Zb~[,  
} XECikld>  
*_#&"(P  
PLdf_/]-  
//保存下载信息（文件指针位置） >Zo-wYG  
private void write_nPos() m#;.yR  
{ %z2oDAjX  
try{ F^]aC98]1  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Vf$1Sjw  
output.writeInt(nStartPos.length); $bFgsy*N2  
for(int i=0;i<nStartPos.length;i++) FCAJavOGH  
{ jceHKl  
// output.writeLong(nPos); 5!8-)J-H  
output.writeLong(fileSplitterFetch.nStartPos); ,8~dz  
output.writeLong(fileSplitterFetch.nEndPos); umryA{Ps  
} y}Cj#I+a  
output.close(); F=:c5z  
} aX]y`  
catch(IOException e){e.printStackTrace ();} m EFWo  
catch(Exception e){e.printStackTrace ();} 6# R;HbkO  
} PK8V2Ttv  
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//读取保存的下载信息（文件指针位置） C
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private void read_nPos() a0 qj[+  
{ 0$!.c~
  
try{ <9T [yg  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); NXi,5  
int nCount = input.readInt(); [-QK$~[ g  
nStartPos = new long[nCount]; 4">84,-N  
nEndPos = new long[nCount]; -^0KE/  
for(int i=0;i<nStartPos.length;i++) S~}$Ly@  
{  r^e-.,+  
nStartPos = input.readLong();  X+\0%|  
nEndPos = input.readLong(); /1U,+g^O>  
} :3:)E  
input.close(); JW2W>6Dgv[  
} Kgps_tY%  
catch(IOException e){e.printStackTrace ();} p<ry$=`  
catch(Exception e){e.printStackTrace ();} ;wfH^2HxE)  
} EccFx7h  
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private void processErrorCode(int nErrorCode) YstXNN4  
{ ~rp.jd 0l  
System.err.println("Error Code : " + nErrorCode); S`iM.;|`O  
} WReYF+Uen  
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Ti /;|lP@  
//停止文件下载 !Mm+bWn=mB  
public void siteStop()  j@s=ER  
{
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bStop = true; "~B~{ _<j  
for(int i=0;i<nStartPos.length;i++) +*WUH513  
fileSplitterFetch.splitterStop(); T "ZQPLg  
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~]jx+6k]  
} -<u- +CbuT  
} o<9yaQ;  
//负责部分文件的抓取 1v+JCOy  
**FileSplitterFetch.java o%y+Y;|?J  
*/ bf&.rJ0  
package NetFox; e-YGuWGN7  
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import java.io.*; Ih9O
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import java.net.*; 1)nM#@%](h  
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public class FileSplitterFetch extends Thread { yHV^a0e7EH  
>"2\D|-/  
I_R5\l}O+D  
String sURL; //File URL !07FsPI#{  
long nStartPos; //File Snippet Start Position N>uZt2  
long nEndPos; //File Snippet End Position RBMMXJ
j  
int nThreadID; //Thread's ID 7zz(#  
boolean bDownOver = false; //Downing is over 8Iqk%n~(  
boolean bStop = false; //Stop identical 3"2<T^H]  
FileAccessI fileAccessI = null; //File Access interface >vNk kxWyQ  
8 RzF].)  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException U>3%!83kF  
{ N7Z(lI|a;  
this.sURL = sURL; ~Sn5;g8+\  
this.nStartPos = nStart; !/=9VD{U!  
this.nEndPos = nEnd; ?[*@T2Ck  
nThreadID = id; 4q@9  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &D&5UdN x  
} .wt>.mUH  
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public void run() 8O;rp(N.n  
{ c=jTs+h'  
while(nStartPos < nEndPos && !bStop) R+@sHsZ@  
{ hz>yv@1  
[h2p8i'o  
t"!8
 
try{ cE_Xo.:Y,  
URL url = new URL(sURL); 4p/V6kr&r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :a^,Ei-&  
httpConnection.setRequestProperty("User-Agent","NetFox"); dKN3ZCw*gF  
String sProperty = "bytes="+nStartPos+"-"; 6{FS/+  
httpConnection.setRequestProperty("RANGE",sProperty); SjNwT[.nr7  
Utility.log(sProperty); h>`'\qy  
* zJiii  
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InputStream input = httpConnection.getInputStream(); B2Awdw3=g  
//logResponseHead(httpConnection); /i]=ndAk  
?-6x]l=]  
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byte[] b = new byte[1024]; }1^tK(Am  
int nRead; A)`fD %+  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) _`Yvfz3  
{ UdM5R [  
nStartPos += fileAccessI.write(b,0,nRead); BzG!Rg|J  
//if(nThreadID == 1) .tHv4.ob  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); uBL~AC3>O  
} Aaw:B?4)  
X:} 5L>'  
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Utility.log("Thread " + nThreadID + " is over!"); W~@GK  
bDownOver = true; iJp!ROI  
//nPos = fileAccessI.write (b,0,nRead); MdTd$ 4J3  
} f+W[]KK*PW  
catch(Exception e){e.printStackTrace ();} /-<m(72wF  
} Pt)}HF|u  
} T;pn -  
%?{2uMfq-f  
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//打印回应的头信息 }JTgj  
public void logResponseHead(HttpURLConnection con) 4>tYMyLt0  
{ J$ih|nP  
for(int i=1;;i++) p-03V"^&  
{ a*wJcJTpV"  
String header=con.getHeaderFieldKey(i); qFsg&<  
if(header!=null) M&\?)yG  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o5G"J"vxe  
Utility.log(header+" : "+con.getHeaderField(header)); u2x=YUWb]  
else ^Th"`Av5  
break; CzsY=DBH=  
} (9q{J(44  
} Xs,PT  
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public void splitterStop() `j"G=%e3.  
{ Y,Zv0-"  
bStop = true; vgp%;-p(  
} -/{}^QWB  
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} } K-[/;  
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/* .`#R%4Xl  
**FileAccess.java *xVAm7_v  
*//文件访问(定位，写) 3kQ8*S  
package NetFox; cZT.vA#  
import java.io.*; [MP:Eeg  
_
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public class FileAccessI implements Serializable{ nL20}"$E  
mn
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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 R*fR?  
RandomAccessFile oSavedFile; A+E@OOw*~  
long nPos; 5&K
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]+7c1MB(5  
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public FileAccessI() throws IOException g'7hc~=  
{ 9yAu<a  
this("",0); GlD'?Mk1  
} eH*b-H[  
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public FileAccessI(String sName,long nPos) throws IOException 3m7V6##+  
{ .g?,:$`0D?  
oSavedFile = new RandomAccessFile(sName,"rw"); %-|q3 ^s  
this.nPos = nPos; 4x=Y9w0?8  
oSavedFile.seek(nPos); dph6aN(49  
} #;]F:TlR  
>g2
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6^u(PzlA|~  
public synchronized int write(byte[] b,int nStart,int nLen) [i#Gqx>'w  
{ 'PbA/MN  
int n = -1; W/Q%%)J  
try{ H2cc).8"  
oSavedFile.write(b,nStart,nLen); X6 cb#s0|  
n = nLen; M3`A&*\;  
} TvwIro  
catch(IOException e) 83*k.]S`  
{ 2oASz|  
e.printStackTrace (); XLxr~Yo  
} /=}vPey  
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return n; hZJqo +s  
} x0GZ2*vfsb  
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} 2jC\yY |PN  
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/* rd{(
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**SiteInfoBean.java RoZV6U~  
*/ +dv@N3GV  
package NetFox; l?[DO?m+R  
CG;D(AWR;  
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public class SiteInfoBean { 2Oa-c|F  
wQc w#  
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private String sSiteURL; //Site's URL }dM^6 Kd%  
private String sFilePath; //Saved File's Path b.;W|$.  
private String sFileName; //Saved File's Name rge/jE,^~Z  
private int nSplitter; //Count of Splited Downloading File }o4Cd$,8  
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public SiteInfoBean() Zpmy)W]1  
{//nSplitter的缺省值为5 (1^(V)@  
//default value of nSplitter is 5 SH.'E Hd  
this("","","",5); tDo0Q/`  
} 25L{bcng  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `upNP/,  
{ MR}\fw$(.  
sSiteURL= sURL; _f`m/l  
sFilePath = sPath; ?x@khzk  
sFileName = sName; XvdhPOMy  
this.nSplitter = nSpiltter; +,lD_{}_  
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& \m\QI  
} v6:DA#0  
\w3wh*  
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public String getSSiteURL() O 2U/zF:X
 
{ C6n
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return sSiteURL; ~#@EjQCq  
} 
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public void setSSiteURL(String value) RjDFc:bB  
{ 1 .M?Hp9i  
sSiteURL = value; ezn>3?S  
} g:Dg
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vXF\PMf  
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public String getSFilePath() eZcm3=WV|  
{ Vr*t~M>  
return sFilePath; _KFKx3<m!  
} F!xK#~e  
S;])Nt'X'  
^6*? a9jO>  
public void setSFilePath(String value) $3L7R  
{ MWl@smRh  
sFilePath = value; Z|W=.RdA;  
} ^tah4QmUA  
_5zR!|\^  
:.dQY=6I  
public String getSFileName() g@QpqrT  
{ v%1#y5  
return sFileName;  rLwc=(|  
} 0^m02\Li  
1$^{Uma  
rdb%/@.-  
public void setSFileName(String value) "\9@gfsp)  
{ eYagI  
sFileName = value; -b{*8(d<I  
} gor6c3i  
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%S^`/Snv"  
public int getNSplitter() 1)r1/0  
{ Cxh9rUe.  
return nSplitter; =3"Nn4Z  
} &(0iSS  
%$cwbh-{{  
p])km%zB(  
public void setNSplitter(int nCount) 
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{ u7/M>YJ`
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nSplitter = nCount; L+,{*Uj[;  
} [J^,_iN[.  
} :70oO}0m.  
M*}
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/* GL/\uq  
**Utility.java PY^Yx$t9  
*/ @1>83-p"X  
package NetFox; Kg.E~  
nhIITfJJ  
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public class Utility { KAe) X_R7  
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public Utility() GJ*AyYG  
{ H[Qh*pq2  
Y`M.hYBXk  
{_ #   
} )ow3Bl8w  
iBZ+gsSP  
//线程睡眠 @p!["v&  
public static void sleep(int nSecond) MM97$  
{ F`-? 3]\3  
try{ Pd3t~1TaW  
Thread.sleep(nSecond); 0]"j,  
} 9)=as/o  
catch(Exception e) Edjh

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{ ^lQe

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e.printStackTrace (); ] $%{nj<  
} H(0d(c1s  
} '- Z4GcL  
>`6^1j(3  
//日志 NoPM!.RU{  
public static void log(String sMsg) ftK.jj1:  
{ UboOIx5:  
System.err.println(sMsg); wo?C7,-x  
} wPV`j:?'  
!1!uB }  
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public static void log(int sMsg) Q,s,EooIx  
{ oVLz7Y[JE  
System.err.println(sMsg); 2)U3/TNe  
} B$7lL
  
} /A_ IS`  
)>=`[$D1t  
SBYRN##n_  
/* <q_H 3|  
**TestMethod.java -,Q<*)q{  
*/ yLI=&7/e@  
package NetFox; %.Mtn%:I*  
A^g81s.5  
c>]_,Br~  
public class TestMethod { +|o-lb  
hI?<F^b  
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public TestMethod() |=7%Edkd  
{ ///xx/weblogic60b2_win.exe t);5Cw
_  
try{ RI%*5lM8;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Gk!v-h9cq  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +[*UC"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $-o39A#  
fileFetch.start(); 8_KXli}7=  
} T nPC\.x  
catch(Exception e){e.printStackTrace ();} |>[w$  
4}8Xoywi1  
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} mV^dIm  
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public static void main(String[] args) }p&aI?-B  
{ L5U>`lx6$  
new TestMethod(); N\H(AzMw  
} K_RrSI&>  
} Q,jlKgB5:  
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