http断点续传简单实现（java)

/* ^b=XV&{q  
**SiteFileFetch.java *MI)]S  
*/ t')h{2&&!2  
package NetFox; Khj=llo,  
import java.io.*; c)03Ms4 D  
import java.net.*; 8\DME  
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public class SiteFileFetch extends Thread { Ss 2$n  
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SiteInfoBean siteInfoBean = null; //文件信息Bean x:qr\Rz  
long[] nStartPos; //开始位置 mY`@'  
long[] nEndPos; //结束位置 lj*8mS/;h  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Yc d3QRB  
long nFileLength; //文件长度 YxJ`-6  
boolean bFirst = true; //是否第一次取文件 ~6kJ~R4  
boolean bStop = false; //停止标志 v~}5u 5$O  
File tmpFile; //文件下载的临时信息 @HvScg*Y  
DataOutputStream output; //输出到文件的输出流 b
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） *="m3:c'J  
public SiteFileFetch(SiteInfoBean bean) throws IOException ~5ubh2{  
{ |YRY!V_w  
siteInfoBean = bean; _jmkl B  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); o!utZmk$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 8)Zk24:])_  
if(tmpFile.exists ()) s@s/'^`  
{ T/5"}P`  
bFirst = false; y@
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read_nPos(); 8?1o<8hV  
} 5U
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else \yG`Sfu2  
{ @zrNN>  
nStartPos = new long[bean.getNSplitter()]; U*qNix  
nEndPos = new long[bean.getNSplitter()]; ec?V[v  
} -w~(3(  
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} 8R}K?+]  
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public void run() sT`^ljp4  
{ g4wZvra6%)  
//获得文件长度 Gs_qO)~xo  
//分割文件 %2D17*eK  
//实例FileSplitterFetch DbtF~`3, .  
//启动FileSplitterFetch线程 <0
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//等待子线程返回 @rwU 1T33  
try{ jV^C19  
if(bFirst) ]'k[u  
{ hwVAXsF~  
nFileLength = getFileSize(); ],[)uTZc  
if(nFileLength == -1) *d>vR1  
{ 94{)"w]  
System.err.println("File Length is not known!"); .oR3Q/|k]  
} 2]2H++  
else if(nFileLength == -2) <GF@L  
{ M4?8xuC  
System.err.println("File is not access!"); O!^; mhy"  
} j[XYj6*d  
else L2fVLKH  
{ M&y5AB0  
for(int i=0;i<nStartPos.length;i++) xo  Gb  
{ }1U*A#aN7K  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ArzDI{1  
} I4D<WoU;dJ  
for(int i=0;i<nEndPos.length-1;i++) NfwYDY  
{ '7tBvVO_  
nEndPos = nStartPos[i+1]; 73 V"s  
} |pW\Ec#(  
nEndPos[nEndPos.length-1] = nFileLength; VVuR+=.&  
} |nY~ZVTt/  
} =_PvrB2'  
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//启动子线程 </s,pe79B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %0XvJF)s  
for(int i=0;i<nStartPos.length;i++) I:$"E% >=  
{ ."mlSW"Wm  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Wx]d $_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Qhy#r  
nStartPos,nEndPos,i); 4D"4zp7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); HY)ESU !  
fileSplitterFetch.start(); {TAw)!R~  
} %8FN0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8S  U%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ;7rv  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "!Lkp2
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nEndPos = " + nFileLength); p=gX!4,9<  
// fileSplitterFetch[nPos.length-1].start(); <1@ (ioPH  
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v0@)t&O  
//等待子线程结束 U7H9/<&o  
//int count = 0; };S0 G!  
//是否结束while循环 'fY9a(Xt.  
boolean breakWhile = false; u^4h&fL  
#I%s3  
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while(!bStop) yA;W/I4  
{ #H5=a6E+q  
write_nPos(); g`?:=G:a*  
Utility.sleep(500); *H2]H@QHN  
breakWhile = true; Gi7RMql6Q  
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for(int i=0;i<nStartPos.length;i++) {p/YCch,  
{ >Ko[Xb-8^_  
if(!fileSplitterFetch.bDownOver) ycX{NDGs  
{ Z[ZDQ o1  
breakWhile = false; |4C^$  
break; m,tXE%l  
} 9UD @MA  
} |_zO_Frtp  
if(breakWhile) v?j!&d>  
break; ~UPZ<  
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//count++; w~+aW(2  
//if(count>4) LP<<'(l`  
// siteStop(); wahZK~,EaY  
} ~F[L4y!sL  
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System.err.println("文件下载结束！"); Pil;/t)"  
} G[z .&l  
catch(Exception e){e.printStackTrace ();} F ?=9eISLJ  
} Y25uU%6t_  
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//获得文件长度 JN[0L:  
public long getFileSize() srmKaa|  
{ PT
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int nFileLength = -1; ^v:Zo  
try{ Y(VO.fVJK  
URL url = new URL(siteInfoBean.getSSiteURL()); C`K^L=8`{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vsMmCd)7U  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7%d8D>uw8  
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int responseCode=httpConnection.getResponseCode(); V|FrN*m  
if(responseCode>=400) Oh; Jw
 
{ G|4^_`-  
processErrorCode(responseCode); .SS<MDcqIt  
return -2; //-2 represent access is error Yl({)qK{  
} z2 hFn&  
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String sHeader; }Dfwm)]Q  
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for(int i=1;;i++) ?IW_O~Js  
{ xeA#u J  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); j]5WK_~M  
//Utility.log(in.readLine()); WUoOGbA `  
sHeader=httpConnection.getHeaderFieldKey(i); HlB]38  
if(sHeader!=null) D"l+iVbBP  
{ b"CAKl  
if(sHeader.equals("Content-Length")) ;L"!I3dM)  
{ YT-=;uK^S  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ")UwkF  
break; X?Pl<l&  
} -$-8W  
} w1^QD^KnH  
else -Zc![cAlO  
break; !m
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} fZN><3MO>  
} J"CJYuGW,  
catch(IOException e){e.printStackTrace ();} C/@LZ OEL  
catch(Exception e){e.printStackTrace ();} ?J!
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Utility.log(nFileLength); ukAKFc^)k  
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return nFileLength; !iu5OX7K|  
} dl|gG9u4Q  
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//保存下载信息（文件指针位置） :0~QRc-u  
private void write_nPos() u=NG6
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{ *dsX#Iz  
try{ AHbZQulC  
output = new DataOutputStream(new FileOutputStream(tmpFile)); _eQ-`?  
output.writeInt(nStartPos.length); Dd $qQ  
for(int i=0;i<nStartPos.length;i++) )e%}b-I'r  
{ &"E lm  
// output.writeLong(nPos); KtN&,C )lJ  
output.writeLong(fileSplitterFetch.nStartPos); NC"yDWnO'  
output.writeLong(fileSplitterFetch.nEndPos); i!H!;z#  
} L'A)6^d@S  
output.close(); <iLM{@lZvJ  
} HEF?mD3h  
catch(IOException e){e.printStackTrace ();} .qD@ Y3-  
catch(Exception e){e.printStackTrace ();} /DFV$+9  
} `wz[='yM  
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p~jlx~1-]  
//读取保存的下载信息（文件指针位置） g
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private void read_nPos() a:Q[gF
8>  
{ q!lP"J  
try{ p.K*UP  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); wa09$
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int nCount = input.readInt(); vT{kL  
nStartPos = new long[nCount]; 7}o/:  
nEndPos = new long[nCount]; c0- ;VZ'  
for(int i=0;i<nStartPos.length;i++) _ -..~K.|  
{ C"V%#
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nStartPos = input.readLong(); nHOr AD|&  
nEndPos = input.readLong(); PX O
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} a:rX9-**  
input.close(); @tT-JwU  
} Djt%r<  
catch(IOException e){e.printStackTrace ();} )0 Z!n  
catch(Exception e){e.printStackTrace ();} Ty4S~ClO#'  
} i775:j~zx0  
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private void processErrorCode(int nErrorCode) vp)Vb^K>  
{ vDj;>VE2b  
System.err.println("Error Code : " + nErrorCode); E#%}ZY  
} @4+#Xd7"  
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B|Wk?w.{r\  
//停止文件下载 z}4L=KR\v  
public void siteStop() "j
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{ rxZi8w>}  
bStop = true; T2'RATfG  
for(int i=0;i<nStartPos.length;i++) m]Y;c_DO:  
fileSplitterFetch.splitterStop(); h
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} A$/\1282  
} $hrIO+  
//负责部分文件的抓取 }M>rE  
**FileSplitterFetch.java )q~DT
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*/ eTay>G  
package NetFox; sp9W?IJ 6c  
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import java.io.*; .giz=*q+  
import java.net.*; P1>AOH2yG  
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public class FileSplitterFetch extends Thread { N#xG3zZl|N  
TYns~X_PR  
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String sURL; //File URL kyw/LE3$-  
long nStartPos; //File Snippet Start Position d=*x#In  
long nEndPos; //File Snippet End Position !vD{Df>  
int nThreadID; //Thread's ID G%lu28}D  
boolean bDownOver = false; //Downing is over El2e~l9  
boolean bStop = false; //Stop identical i{c@S:&@^  
FileAccessI fileAccessI = null; //File Access interface TX8<J>x  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException csZc|kDI  
{ xJ8%<RR!t  
this.sURL = sURL; q%YV$$c  
this.nStartPos = nStart; KDP H6  
this.nEndPos = nEnd; yCz|{=7"j  
nThreadID = id; ~ Hy,7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :nY
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} GbP!9I  
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public void run() uGN^!NG-0  
{ m} ?r
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while(nStartPos < nEndPos && !bStop) \00DqL(Oj`  
{ ef!
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try{ %(/!ljh_  
URL url = new URL(sURL); @F*wg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  kzmQm  
httpConnection.setRequestProperty("User-Agent","NetFox"); 'J)2g"T@  
String sProperty = "bytes="+nStartPos+"-"; VhGs/5  
httpConnection.setRequestProperty("RANGE",sProperty); T'-FV  
Utility.log(sProperty); +k<w!B*  
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InputStream input = httpConnection.getInputStream();
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//logResponseHead(httpConnection); zLw{ {|  
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byte[] b = new byte[1024]; G$zL)R8GE|  
int nRead;  _?voU  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1k%k`[VC  
{ %6%<?jZ  
nStartPos += fileAccessI.write(b,0,nRead); -D^A:}$  
//if(nThreadID == 1) j9+I0>#X  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Lw7=+h)  
} 9Mp$8-=>7  
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Utility.log("Thread " + nThreadID + " is over!"); 6(|d|Si *c  
bDownOver = true; Mp$@`8X`  
//nPos = fileAccessI.write (b,0,nRead); ma$Prd  
} <AlZ]
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catch(Exception e){e.printStackTrace ();} yqXH:757~  
} YNrp}KQ  
} y)c5u%(  
2 !" XzdD  
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//打印回应的头信息 I:V0Xxz5t  
public void logResponseHead(HttpURLConnection con) dBV7Te4L  
{ \qvaE+  
for(int i=1;;i++) )QagS.L{z  
{ m4E)qCvy  
String header=con.getHeaderFieldKey(i); }{9&:!uA  
if(header!=null)
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//responseHeaders.put(header,httpConnection.getHeaderField(header)); V(MFna)  
Utility.log(header+" : "+con.getHeaderField(header)); s#Jh -+lM  
else :4S%'d7  
break; 7`IpBm<  
} I V%VU  
} e6B{QP#jq  
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public void splitterStop() Cd79 tu|  
{ g[>\4B9t  
bStop = true; t%zpNd2lk  
} $uui:wU%Q  
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+(D$9{y  
} f=!PllxL:  
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/* `u!l3VZ/4  
**FileAccess.java @UBjq%z  
*//文件访问(定位，写) b?4/#&z]  
package NetFox; qQi.?<d2"s  
import java.io.*; o[ENp'r  
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public class FileAccessI implements Serializable{ z)XRx:YU;$  
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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 B()/.w?A  
RandomAccessFile oSavedFile; &~UJf4b|A  
long nPos; 8;y&Pb~)  
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public FileAccessI() throws IOException cw&Hgjj2  
{ y~ G.V,0  
this("",0); 6~#Ih)K  
} E|YdcS  
{ 74mf'IW  
6OiSK@<Hk  
public FileAccessI(String sName,long nPos) throws IOException Iu~\L0R427  
{ FLoNE>q  
oSavedFile = new RandomAccessFile(sName,"rw"); 4$/i%B#ad  
this.nPos = nPos; 2RF^s.W  
oSavedFile.seek(nPos); e&MC|US=\  
} }7{t^>;D  
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public synchronized int write(byte[] b,int nStart,int nLen) a"/#+=[  
{ IfO;S*Qt  
int n = -1; ^ yh'lh/  
try{ xX0-]Y h:  
oSavedFile.write(b,nStart,nLen); 2;L|y._`w  
n = nLen; ?::NO Dg  
} D2YZ9e
  
catch(IOException e) oIGrA-T}  
{ V&soN:HS  
e.printStackTrace (); !KKT[28v  
} p3ISWJa!  
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return n; Lf:uNl*D  
} R
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} dAP|:&y@  
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/* 2:}fe}  
**SiteInfoBean.java NT%W;)6m9  
*/ ;E~4)^  
package NetFox; i$^)UZJ&0  
"HD+rmUEH  
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public class SiteInfoBean { /Y[~-Y+!,  
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private String sSiteURL; //Site's URL qP!eJ6[Nh"  
private String sFilePath; //Saved File's Path D+V7hpH-  
private String sFileName; //Saved File's Name z^o1GY  
private int nSplitter; //Count of Splited Downloading File KDi|(  
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public SiteInfoBean() p6EDQwlf  
{//nSplitter的缺省值为5 AJt!!crs  
//default value of nSplitter is 5 nU+tM~C%a  
this("","","",5); QH4wUU3X  
} Z>F^C}
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (VvKGh  
{ 50jOA#l[  
sSiteURL= sURL; +y[@T6_  
sFilePath = sPath; #gQ
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sFileName = sName; Xog/O i  
this.nSplitter = nSpiltter; @e~]t}fH  
5yh/0i5|  
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} >1L=,M  
~Y=@$!Uq  
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public String getSSiteURL() !yjo   
{ |ifHSc.j<  
return sSiteURL; WV;=@v  
} '/0#lF  
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public void setSSiteURL(String value) '6Qy/R  
{ pvWau1ArNq  
sSiteURL = value; v=YK8fNi  
} 5`^o1nGO'  
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public String getSFilePath() v|Jlf$>  
{ B,$l4m4  
return sFilePath; \v@({nB8  
} PsjbR  
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public void setSFilePath(String value) .r|*Ch#;P  
{ 2H#N{>7  
sFilePath = value; AH7L.L+$M  
} D _X8-  
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public String getSFileName() ~d>%,?zz  
{ A(6xg)_XQ  
return sFileName; `hh9"Ws%  
} 4|J[Jdj  
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public void setSFileName(String value) O>r-]0DI[  
{ ]o.vB}WsY  
sFileName = value; S*W;%J5  
} GrEs1M1]*  
eBB:~,C^q.  
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public int getNSplitter() -<f/\U  
{ kN9yO5h7  
return nSplitter; sLh0&R7   
} "Tbnxx]J  
7|YrdK<  
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public void setNSplitter(int nCount) oN2=DYC41  
{ z MdC  
nSplitter = nCount; I=dGq;Jaz  
} $%qg"  
} gtU1'p"  
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/* 3P=w =~e  
**Utility.java ksI>IW  
*/ lglYJ,  
package NetFox; ~uaP$*B[  
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public class Utility { CMVS W6  
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public Utility() UVX"fZ)  
{ "n?<2 wso  
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} : }?{@#Z  
v[#)GB _5  
//线程睡眠 1kFjas`g  
public static void sleep(int nSecond) c~tAvDX  
{ R{3CW^1
  
try{ vA?_-.J  
Thread.sleep(nSecond); j7/(sf  
} f'{>AKi=C  
catch(Exception e) LHi6:G"Y(  
{ n(&*kfk  
e.printStackTrace (); DX@}!6|T  
} 31XU7
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} Npa-$N&P{S  
0n5UKtB  
//日志 DP>mNE  
public static void log(String sMsg) f=ib9WbR#  
{ &'O?es|Lb  
System.err.println(sMsg); h~ha  
} YNM\p
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public static void log(int sMsg) D@hmO]5c  
{ < l[
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System.err.println(sMsg); {wu!6\:<??  
} t<lyg0f  
} Zr"dOj$Jf  
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/* bOXh|u_3i  
**TestMethod.java iEhDaC[e(b  
*/ 2u&c &G  
package NetFox; )6G+tU'  
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public class TestMethod { liG~
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h544dNo&  
public TestMethod() ~~dfpW_"  
{ ///xx/weblogic60b2_win.exe 6DZ2pT:  
try{ nDn{zea7  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); t^$Div_%G  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M=Is9)y  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }2xb&6g~o  
fileFetch.start(); )`RZkCe  
} gT7I9 (x!W  
catch(Exception e){e.printStackTrace ();} R7t bxC  
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""  
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} /2'c>  
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public static void main(String[] args) ^ N_`^m  
{ k7[)g]u  
new TestMethod(); s @3zx  
} JgZdS-~  
} fa.f(c
  
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