http断点续传简单实现（java)

/* F !g>fIg  
**SiteFileFetch.java 3|x*lmit  
*/ #eadkj#;  
package NetFox; E">FH>8K}  
import java.io.*; Dukvi;\  
import java.net.*; P
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public class SiteFileFetch extends Thread { G'<:O(Imu  
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SiteInfoBean siteInfoBean = null; //文件信息Bean &y_Ya%Z3*e  
long[] nStartPos; //开始位置 /6",#B}%b  
long[] nEndPos; //结束位置 0P i+ (X  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @ >_v/U'  
long nFileLength; //文件长度 v,]-;V~<  
boolean bFirst = true; //是否第一次取文件 Wg{ 9X#|  
boolean bStop = false; //停止标志 t$~CLq5ad  
File tmpFile; //文件下载的临时信息 0])D)%B k  
DataOutputStream output; //输出到文件的输出流 fSc)PqLP  
R `K1L!`3  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类）  qHVZsZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException s R/z)U_  
{ X6 E^5m  
siteInfoBean = bean; `st3iTLZY  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |xYr0C[Pq  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); KEfN!6
 
if(tmpFile.exists ()) p.@
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{ !U::kr=t  
bFirst = false; m4\e`nl  
read_nPos(); gpT~3c;l=  
} VN3[B eH  
else J(>T&G;  
{ iy!SqC  
nStartPos = new long[bean.getNSplitter()]; ~}"5KX\=#  
nEndPos = new long[bean.getNSplitter()]; -XASS%  
} B<$(
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} v_|k:l  
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public void run() XgI;2Be+&a  
{ 6L<Y   
//获得文件长度 jhR`%a
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//分割文件 =O%Hf bx  
//实例FileSplitterFetch
O\J{4EB@.  
//启动FileSplitterFetch线程 f/95}6M  
//等待子线程返回 c/lT S  
try{ <EKTFHJ!  
if(bFirst) C;3  
{ Y'y yrn}  
nFileLength = getFileSize(); b|-}?@&7&q  
if(nFileLength == -1) t i&!_  
{ "IHFme@^  
System.err.println("File Length is not known!"); u|"y&
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} e_YTh^wU  
else if(nFileLength == -2) b+`qGJrej  
{ ;I9g;}  
System.err.println("File is not access!"); 4#,,_
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} S3UJ)@ E  
else BgT(~8'  
{ 4V&(w,zl  
for(int i=0;i<nStartPos.length;i++) TKp2C5bX  
{ "+M0lGTB  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 704_ehrlE  
} MTip4L W9  
for(int i=0;i<nEndPos.length-1;i++) 3#?53s  
{ <A(Bq'eQM  
nEndPos = nStartPos[i+1]; bcgXpP  
} IISdC(5  
nEndPos[nEndPos.length-1] = nFileLength; "$/1.SX;]  
} fg7  
} sXm
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Y P,>vzW  
T/FZn{I  
//启动子线程 Eunmc  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~h:(9q8NLC  
for(int i=0;i<nStartPos.length;i++) 6zi 5#23  
{ #KNl<V+c}1  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nYR#Q|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), erKi*GssZ  
nStartPos,nEndPos,i); N!fjN >cw  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S17;;w0  
fileSplitterFetch.start(); 3Vbt(K  
} FTr'I82m(  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UhJ{MUH`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); gA`QV''/:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~{$c|  
nEndPos = " + nFileLength); &=f?:UZ%  
// fileSplitterFetch[nPos.length-1].start(); xs&xcRR"  
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\H9:%Tlp~4  
//等待子线程结束 JVGTmS[3  
//int count = 0; IT7],pM  
//是否结束while循环 +MD84YR  
boolean breakWhile = false; l,~`o$_  
D2GF4%|  
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while(!bStop) QJ(5o7Tfn  
{ 6Xz d>5x  
write_nPos(); CiGXyhh  
Utility.sleep(500); 'oK oF  
breakWhile = true; =j{tFxJ  
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for(int i=0;i<nStartPos.length;i++) rB{w4  
{ g*(z.  
if(!fileSplitterFetch.bDownOver) \#xq$ygg  
{ SQhVdYU1'  
breakWhile = false; :b*7TJ\grN  
break; 97UOH  
} /G|v.#2/g  
} &AOGg\  
if(breakWhile) nF_q{e7  
break; KK
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//count++; gS'7:UH,
  
//if(count>4) )bR0>3/  
// siteStop(); O_
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} NJ+$3n om  
4H(8BNgzV  
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System.err.println("文件下载结束！"); j7MUA#6$  
} &A*E)T#>#  
catch(Exception e){e.printStackTrace ();} FwlDP  
} 6dmb bgO)  
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//获得文件长度 jL8A_'3B  
public long getFileSize() l^}u S|c(  
{ u:lBFVqk  
int nFileLength = -1; VBQAkl?(}4  
try{ d,N6~?B  
URL url = new URL(siteInfoBean.getSSiteURL()); 5I,NvHD4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fkp(M  
httpConnection.setRequestProperty("User-Agent","NetFox"); bL`\l!qQx;  
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~]
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int responseCode=httpConnection.getResponseCode(); .B-b51Uz  
if(responseCode>=400) ,*U-o}{8C?  
{ ?4U4o<   
processErrorCode(responseCode); 
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return -2; //-2 represent access is error ?8{Os;!je  
} 6WQN!H8+^  
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String sHeader; g*My1+J!  
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for(int i=1;;i++) ]T'8O`  
{ TK18U*z7J  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); H390<`  
//Utility.log(in.readLine()); q[VQ?b~9  
sHeader=httpConnection.getHeaderFieldKey(i); .pWRV<25  
if(sHeader!=null) zHz>Gc  
{ NZv8#  
if(sHeader.equals("Content-Length")) U ->vk{v  
{ ;Us6:}s  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #*.4Jv<R  
break; B=K<k+{6"  
} 6Aqv*<1=62  
} Qc-W2%  
else 9)]`le  
break; Y\_mqd  
} gizY4~ j  
} qjkWCLOd  
catch(IOException e){e.printStackTrace ();} #&IrCq+  
catch(Exception e){e.printStackTrace ();} w9GY/]  
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Utility.log(nFileLength); #aC&!Rei{  
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return nFileLength; -u%o);B  
} sq#C|v/  
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//保存下载信息（文件指针位置） k7*-v/*S  
private void write_nPos() 6zU0 8z0-  
{ [= E=H*j  
try{ T<7}IH$6xE  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8q9^  
output.writeInt(nStartPos.length); _?{KTgJG  
for(int i=0;i<nStartPos.length;i++) Th%w-19,8  
{ "[["naa  
// output.writeLong(nPos); D&mPYxXL  
output.writeLong(fileSplitterFetch.nStartPos); =r]_$r%gR  
output.writeLong(fileSplitterFetch.nEndPos); -M]/Xv]  
} #oEtLb@O  
output.close(); LL3| U  
} *B&i`tq  
catch(IOException e){e.printStackTrace ();} 6I=d0m.io  
catch(Exception e){e.printStackTrace ();} ?cz7s28a  
} mL}Wan  
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 nSo.,72  
//读取保存的下载信息（文件指针位置） b9.7j!W  
private void read_nPos() Gv)*[7  
{ o%]b\Vl6  
try{ su\Lxv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); E?K(MT&@  
int nCount = input.readInt(); ?=iy 6q  
nStartPos = new long[nCount]; d<\
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nEndPos = new long[nCount]; uh)f/)6  
for(int i=0;i<nStartPos.length;i++) w{;bvq%lY  
{  :5^5l  
nStartPos = input.readLong(); =}0>S3a.7  
nEndPos = input.readLong(); #CeWk$)m  
} P6^\*xkMr  
input.close(); \3U.;}0_X  
} [e.`M{(TB  
catch(IOException e){e.printStackTrace ();} `o+J/nc  
catch(Exception e){e.printStackTrace ();} )J\ JAUj  
} jw2hB[WR  
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i}:^<jDv?  
private void processErrorCode(int nErrorCode) !qs~j=;y3  
{ gavf$be  
System.err.println("Error Code : " + nErrorCode); r`0oI66B/  
} #{bT=:3a  
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//停止文件下载 N':d T  
public void siteStop() w01\KV  
{ &eg@ZnPn  
bStop = true; W6*5e{  
for(int i=0;i<nStartPos.length;i++) Dm;aTe  
fileSplitterFetch.splitterStop(); P'5Q}7  
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} UD]RW
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} zZCssn;[  
//负责部分文件的抓取 ^zS|O]Tx  
**FileSplitterFetch.java wAF#N1-k  
*/ nfr..4,:  
package NetFox; {1wjIo"ptg  
/(ArA=#  
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import java.io.*; 'F8:|g  
import java.net.*; za4:Jdr  
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}  
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public class FileSplitterFetch extends Thread { ?)c9!hR  
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 A,|lDsvM  
String sURL; //File URL '%A*Z,f  
long nStartPos; //File Snippet Start Position h IUO=
f  
long nEndPos; //File Snippet End Position |f&=9%  
int nThreadID; //Thread's ID p8u-
3  
boolean bDownOver = false; //Downing is over yYZ0o.<&T*  
boolean bStop = false; //Stop identical )VR/a  
FileAccessI fileAccessI = null; //File Access interface IY9##&c3>  
>_?Waz%  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException M6b6lhg  
{ [mI;>q  
this.sURL = sURL; ?`D/#P  
this.nStartPos = nStart; 'd 6z^Z6  
this.nEndPos = nEnd; @460r  
nThreadID = id; ?wS/KEl=O  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .Cf`D tK  
} tqe8:\1yK  
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public void run() Bl)DuCV  
{ h/n&&J  
while(nStartPos < nEndPos && !bStop) @5\ns-%  
{ )o8]MWT\;  
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try{ uCNi&
.  
URL url = new URL(sURL); T"$yh2tSY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <U() *0  
httpConnection.setRequestProperty("User-Agent","NetFox"); ta 66AEc9  
String sProperty = "bytes="+nStartPos+"-"; Jk!*j  
httpConnection.setRequestProperty("RANGE",sProperty); ]1 OZY@  
Utility.log(sProperty); mxV0"$'Fm  
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tk <R|i  
InputStream input = httpConnection.getInputStream(); 7 a}qnk%  
//logResponseHead(httpConnection); k/ 9S  

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byte[] b = new byte[1024]; .UuCTH;6`  
int nRead; IA XoEBlMs  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \We\*7^E  
{ 2%Y]M%P  
nStartPos += fileAccessI.write(b,0,nRead); yJ&`@gB  
//if(nThreadID == 1) uxd5XS  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O+o1R24JI  
} X^U)j N2  
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Utility.log("Thread " + nThreadID + " is over!"); ,wN>
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bDownOver = true; '
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//nPos = fileAccessI.write (b,0,nRead); (*Jcx:rH  
} RTW4r9~'  
catch(Exception e){e.printStackTrace ();} F`$V H^%V  
} Tc DkKa  
} N{u4  
p<2A4="&  
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//打印回应的头信息 JEK6Ms;)A  
public void logResponseHead(HttpURLConnection con) ZV`D} CQ  
{ ",c(cYVW  
for(int i=1;;i++) #l6L7u0~wC  
{ 8()L}
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String header=con.getHeaderFieldKey(i); 5m`@ 4%)zp  
if(header!=null) 4{h?!Z*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); QGYO{S  
Utility.log(header+" : "+con.getHeaderField(header)); F(-Q]xj,  
else n y7
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break; t UJ m}+=>  
} }2^_Gaj  
} aD aQ7i  
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public void splitterStop() q^ {Xn-G  
{ dcMWCK  
bStop = true; ZqHh$QBD 9  
} T>l=0a #  
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} d~](S<k  
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/* HL;y5o?  
**FileAccess.java Y|t]bb  
*//文件访问(定位，写) N@$g"w  
package NetFox; @'.(62v  
import java.io.*; ~VZ)LQ'7  
iV!o)WvG,F  
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public class FileAccessI implements Serializable{ %(GWR@mfC  
`)
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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 Np4';
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RandomAccessFile oSavedFile; NPws^  
long nPos; .0l0*~[  

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public FileAccessI() throws IOException <StyO[  
{ #<V/lPz+  
this("",0); -4|\,=j  
} qJ=4HlLno  
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public FileAccessI(String sName,long nPos) throws IOException Az29?|e  
{ gTE/g'3  
oSavedFile = new RandomAccessFile(sName,"rw"); ?{W@TY@S  
this.nPos = nPos; XK[cbVu  
oSavedFile.seek(nPos); X}.y-X#v5J  
} D9 ~jMcX  
5[.Dlpa'7  
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public synchronized int write(byte[] b,int nStart,int nLen) VG*Tdaua~  
{ E5D5  
int n = -1; 413,O~^  
try{ OOy]:t4 /  
oSavedFile.write(b,nStart,nLen); lP*_dt9  
n = nLen; B#Rw
W,  
} bD_|n!3  
catch(IOException e) >U\,(VB  
{ }eUeADbC  
e.printStackTrace (); }gQ FWT  
} X~ n=U4s}O  
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return n; J;|r00M  
} (uV~1  
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} }oHA@o5  
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/* InDISl]  
**SiteInfoBean.java %N 8/g]`7  
*/ H^cB?i  
package NetFox; i$HA@S  
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public class SiteInfoBean { qMT7g LB'1  
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x ;V7D5 q  
private String sSiteURL; //Site's URL / sI0{  
private String sFilePath; //Saved File's Path :7&#ej6  
private String sFileName; //Saved File's Name J [}8&sn  
private int nSplitter; //Count of Splited Downloading File "Ka2jw,  
RUHQ]@d#T  
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public SiteInfoBean() >SO !{  
{//nSplitter的缺省值为5 G0p|44_~t  
//default value of nSplitter is 5 /Po't(-x  
this("","","",5); a1]@&Dr  
} 1 FTxbw@  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6u>${}  
{ v;.7-9c*  
sSiteURL= sURL; 2O\p`,.  
sFilePath = sPath; lA[BV7.=7  
sFileName = sName; L{fKZ  
this.nSplitter = nSpiltter; C.I.f9s?R  
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7\*_/[
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} E!.>*`)?.  
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public String getSSiteURL() L\d"|87lX  
{ M\5aJ:cQ+  
return sSiteURL; *nUD6(@g  
} 4B>N[#-0=  
#"{w
m  
4%L`~J4 wr  
public void setSSiteURL(String value) 3@XkO  
{ JWhi*je  
sSiteURL = value; !#0Lo->OO  
} ;=goIsk{Q  
u0M[B7Q  
w"Gci~]bXU  
public String getSFilePath() B"rV-,n{  
{ 8,\toT7  
return sFilePath; R;+vE'&CO  
} ?@"F\Bv<h  
7x8/Vz@\  
" `rkp=  
public void setSFilePath(String value) 5yPw[ EY  
{ m
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sFilePath = value; 8Jnb/A}  
} f9FJ:?  
YlfzHeN1  

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public String getSFileName() ?.1yNO*s  
{ y;zp*(}f$h  
return sFileName; F_>OpT  
} b1An2e[  
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[(Z{5gK  
public void setSFileName(String value) l/?Jp+]  
{ JC|j*x(k/  
sFileName = value; vv0A5p8H  
} E= 3Ui  
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Ph@hk0dgr/  
public int getNSplitter() CK4C:`YG  
{ \@")2o+  
return nSplitter; `M0m`Up  
} ^{f^%)X  
WdQR^'b$  
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public void setNSplitter(int nCount) XMt)\r.  
{ a=m4)tjk  
nSplitter = nCount; D^]g`V*N  
} dMn0nc+  
}
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}Xa1K;KM{  
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/* GYp}V0  
**Utility.java C/3
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*/ V)|]w[(Y  
package NetFox; K+HP2|#6  
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public class Utility { Epo/}y  
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o8uak*"{  
public Utility() a]=k-Xh  
{ utSW>  
},eV?eGj  
?$v*_*:2h  
} Qs\m"yx  
(FVHtZi7  
//线程睡眠 E\/J& .  
public static void sleep(int nSecond) K9\r2w'T'  
{ +f
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try{ l%\p  
Thread.sleep(nSecond); Z'!Ii+'6  
} 5rX_85]  
catch(Exception e) rt8"U<~  
{ 7)-uYi] dA  
e.printStackTrace (); (T65pP_P 7  
} @~ 6,8nQ  
} i>j(Dsv  
UlNx5l+k  
//日志
w ]%EJ|'  
public static void log(String sMsg) &x"hM  
{ ^n%
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System.err.println(sMsg); eeVzOq(  
} 3[*x'"Q;H  
~pt#'65}:  
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public static void log(int sMsg) ']C" 'b  
{ };m.8(}$)  
System.err.println(sMsg); ,DIr&5>p2  
} n_9Wrx328  
} nvInq2T
1  
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/* hd>_K*oH  
**TestMethod.java MwE^.6xl{  
*/ Wr6y w#
 
package NetFox; a/Ik^:>m  
w,zm$s^  
v"x'rx#  
public class TestMethod { ?mbI6fYv  
Ha/Gn!l  
:G4)edw
e  
public TestMethod() Iy;bzHXs  
{ ///xx/weblogic60b2_win.exe __Egr@  
try{ ,<O|#`?"@G  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Uqd2{fji=#  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); WqRaD=R->;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); zbZN-j#  
fileFetch.start(); zlhU[J}"1|  
} rd ]dDG  
catch(Exception e){e.printStackTrace ();} H=@S+4_bK  
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#9/S2m2\YG  
} {(5M)|>  
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public static void main(String[] args) eMOnzW|h  
{ Ou5,7Ne  
new TestMethod(); 'fka?lL  
} evE$$# 6R  
} *kq>Z 06'i  
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