http断点续传简单实现（java)

/* ^Xs]C|=W  
**SiteFileFetch.java T8Na]V5  
*/ K<RqBecB  
package NetFox; x0<^<D&Q  
import java.io.*; 0T9.M(  
import java.net.*; " "%#cDR  
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public class SiteFileFetch extends Thread { `D2Mss$!  
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SiteInfoBean siteInfoBean = null; //文件信息Bean V.VJcx  
long[] nStartPos; //开始位置 Nog(VN4I&  
long[] nEndPos; //结束位置 zP
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FileSplitterFetch[] fileSplitterFetch; //子线程对象 mb{q(WEPP  
long nFileLength; //文件长度 YgimJsm  
boolean bFirst = true; //是否第一次取文件 ~ffwLgu!  
boolean bStop = false; //停止标志 P }Te"Y  
File tmpFile; //文件下载的临时信息 p6[ (81  
DataOutputStream output; //输出到文件的输出流 -;Uj|^  
1`l;xw1W  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） D#0O[F@l##  
public SiteFileFetch(SiteInfoBean bean) throws IOException
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{ <\aU"_D   
siteInfoBean = bean; e=>
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); G~!C=l  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "% Y u wMY  
if(tmpFile.exists ()) "8/dD]=f^a  
{ V^rW?Do  
bFirst = false; ^
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read_nPos(); uJ8{HB  
} -J?~U2  
else D=&K&6rr  
{ ?,XC=}  
nStartPos = new long[bean.getNSplitter()]; S#2[%o  
nEndPos = new long[bean.getNSplitter()]; 2w4MJ,Uw  
} ri+U0[e3  
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} !^v\^Fc  
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public void run() %rcFT_  
{ jBRPR R0  
//获得文件长度 N`1r;%5  
//分割文件 lRND  
//实例FileSplitterFetch r/PKrw sC  
//启动FileSplitterFetch线程 !G+u j(  
//等待子线程返回 aR)?a;}H  
try{ ik\S88|  
if(bFirst) 7>,rvW:]  
{ GYoseqZM  
nFileLength = getFileSize(); .'lN4x  
if(nFileLength == -1) 3dm'xetM  
{ Ef,Cd[]b  
System.err.println("File Length is not known!"); >FF1)~  
} [hHG.  
else if(nFileLength == -2) jVYH;B%%z  
{ \
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System.err.println("File is not access!"); /^4"Qv\@/  
} VQ<5%+  
else zYr z08PJ  
{ UH20n{_:  
for(int i=0;i<nStartPos.length;i++) Ub)M*Cq0(o  
{ aQ|hi F}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8*Zvr&B,G  
} 4bI*jEc\[  
for(int i=0;i<nEndPos.length-1;i++) M&[b.t*  
{ F$yeF^\g  
nEndPos = nStartPos[i+1]; [Vp\$;\nT  
} @T7PZB&xnl  
nEndPos[nEndPos.length-1] = nFileLength; , N 344y  
} :e2X/tl#  
} q"nGy#UWR  
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$?f]ZyZr.  
//启动子线程 =P]GPEz_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !nzGH*td  
for(int i=0;i<nStartPos.length;i++) PEzia}m  
{ @?a4i  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), W~NYU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7$_ :sJ  
nStartPos,nEndPos,i); 7I3:u+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Jck"Ks  
fileSplitterFetch.start(); H,|YLKg-|  
} 4z0L ke  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), / O)6iJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >{XScxaB`  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !Uy>eji}  
nEndPos = " + nFileLength); e1^l.>2d6  
// fileSplitterFetch[nPos.length-1].start(); |y
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c&e0OV\m  
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//等待子线程结束 ZNL5({lv  
//int count = 0; s=U\_koyH  
//是否结束while循环 ke6n/ h5`  
boolean breakWhile = false; g;G5 r&T  
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while(!bStop) !*bdG(pK  
{ oHsP
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write_nPos(); `M]BhW)  
Utility.sleep(500); PL@7KDQ  
breakWhile = true; 5/(sjMB  
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for(int i=0;i<nStartPos.length;i++) Yxqj -   
{ !I7?  
if(!fileSplitterFetch.bDownOver) ~U%j{8uH  
{ O
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breakWhile = false; ?O7iK<5N  
break; kfK[u/<i  
} (9
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} Yb9cW\lr  
if(breakWhile) 0BDS_Rx  
break; w4A#>;Qu*  
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7LdzZS0OM  
//count++; G?ZC9w]rA  
//if(count>4) mATH*[Y  
// siteStop(); 3'^S3W%  
} ?i%nMlcc  
k=|K|  
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System.err.println("文件下载结束！"); zq=&4afOE  
} t= *Jg/$  
catch(Exception e){e.printStackTrace ();} Hz?,#>{
  
} y/\ZAtnLo  
;sQ20 B'  
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//获得文件长度 _yJ|`g]U3  
public long getFileSize() Ql8^]gbp+  
{ KBj@V6Q  
int nFileLength = -1; y#e ?iE@  
try{ SwJHgZ&  
URL url = new URL(siteInfoBean.getSSiteURL()); ,!H\^Vfl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); #[(gIOrNn8  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q@Dkl F  
)Y8qWJU  
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int responseCode=httpConnection.getResponseCode(); c/RT0xql*  
if(responseCode>=400) eA
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{ Gym#b{#":  
processErrorCode(responseCode); ZQ|gt*  
return -2; //-2 represent access is error t%HI1eO7h  
} z L8J`W  
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!mae^A1  
String sHeader; ]_\AHnJ  
q|Fjm]AF  
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for(int i=1;;i++) AoU_;B\b%  
{ q#m!/wod  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); J@gm@ jLc  
//Utility.log(in.readLine()); "u5KbJW  
sHeader=httpConnection.getHeaderFieldKey(i); PY\W  
if(sHeader!=null) jJ<;2e~OW  
{ (gDQ\t@3-  
if(sHeader.equals("Content-Length")) X98#QR#m  
{ lJlhl7  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $':
JI#  
break; 6+?wnp-  
} G ~A$jStm
 
} H7}g!n?  
else >~^`5a`$uI  
break; T?#s'd  
} nfa_8  
} \#2 s4RCji  
catch(IOException e){e.printStackTrace ();} [\a:4vDAbi  
catch(Exception e){e.printStackTrace ();} ^8Z@^
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Utility.log(nFileLength); jQ)L pjS1  
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return nFileLength; 6UO$z-e  
} OelU D/[$  
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//保存下载信息（文件指针位置） 2'Y{FY_Z  
private void write_nPos() nPcxknl(pd  
{ a^(2q{*  
try{ ^glX1 )  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {N"*olx  
output.writeInt(nStartPos.length); 7MoR9,(  
for(int i=0;i<nStartPos.length;i++) }|SIHz!R  
{ 6-tiRk~  
// output.writeLong(nPos); %pH)paRAP  
output.writeLong(fileSplitterFetch.nStartPos); 1*L^^%w  
output.writeLong(fileSplitterFetch.nEndPos); =pyVn_dg  
} jmSt?M0.xV  
output.close(); z+ uL "PG[  
} }'PG!+=I  
catch(IOException e){e.printStackTrace ();} Etw~*  
catch(Exception e){e.printStackTrace ();} & \JLTw  
} 4`$5 _} j!  
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//读取保存的下载信息（文件指针位置） nT#37v  
private void read_nPos() &yB%QX{3  
{ s:3aRQ%  
try{ g%ZdIKj!  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Bj; [  
int nCount = input.readInt(); (x}A_i  
nStartPos = new long[nCount]; 1E8$% 6VV  
nEndPos = new long[nCount]; /9P^{OZ;y  
for(int i=0;i<nStartPos.length;i++) A0S8Dh$  
{ 6={IMkmA  
nStartPos = input.readLong(); RXUA!=e  
nEndPos = input.readLong(); 7,f:Qi@g  
} `(P "u  
input.close(); EG%I1F%  
} mZ]P[lQ'5  
catch(IOException e){e.printStackTrace ();} ?n2C  
catch(Exception e){e.printStackTrace ();} *3!(*F@M,  
} dr.**fGYde  
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private void processErrorCode(int nErrorCode) E=}6X9X  
{ vz- 9<w;>a  
System.err.println("Error Code : " + nErrorCode); yq1Gqbh l  
} qI(W$  
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aXQ&@BZ{j  
//停止文件下载 Ad^dF'SN  
public void siteStop() SE6>vKR/.  
{ UP}feN  
bStop = true; 3(MoXA*  
for(int i=0;i<nStartPos.length;i++) *@CVYJ'<  
fileSplitterFetch.splitterStop(); ?){0-A4  
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} 3(aRs?/O  
} u
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//负责部分文件的抓取 D% oueW  
**FileSplitterFetch.java }*0,>w>  
*/ x6"/z  
package NetFox; ur?d6a  
n; Lo  
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import java.io.*;
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import java.net.*; zB;'
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joxS+P5#  
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public class FileSplitterFetch extends Thread { th5 X?so  
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String sURL; //File URL $Vo/CZW7  
long nStartPos; //File Snippet Start Position 8FAT(f//.  
long nEndPos; //File Snippet End Position $$k7_rs  
int nThreadID; //Thread's ID r5D jCV"  
boolean bDownOver = false; //Downing is over  -PcS(  
boolean bStop = false; //Stop identical Cw6>^  
FileAccessI fileAccessI = null; //File Access interface n>u.3wL  
iU.!oeR?  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1R5Yn(  
{ s.|!Ti!]  
this.sURL = sURL; xt?3_?1  
this.nStartPos = nStart; AmP#'U5  
this.nEndPos = nEnd; ue,#,
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nThreadID = id; <l*agH-.3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 rdXCWK$E  
} n;e."^5  
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public void run() ,lrYl!,  
{ kEp.0wL'  
while(nStartPos < nEndPos && !bStop) X(4s;i  
{ <ED8"~_  
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co \[{}}  
try{ _cW_u?0X:  
URL url = new URL(sURL); GwTT+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *>EI2HX  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8dV.nO  
String sProperty = "bytes="+nStartPos+"-"; Y'tqm&}  
httpConnection.setRequestProperty("RANGE",sProperty); 6"BtfQ")  
Utility.log(sProperty); Q&oC]u(="&  
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InputStream input = httpConnection.getInputStream(); |z.Gh1GCy  
//logResponseHead(httpConnection); $ \? N<W  
x, G6\QmA  
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byte[] b = new byte[1024]; 5LDQ^n  
int nRead; 6H(fk1E  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) G> f^2  
{ CnxK+1n
l  
nStartPos += fileAccessI.write(b,0,nRead); Nr>c'TH  
//if(nThreadID == 1) 4JX`>a{<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /X(@|tk:  
} #JK;&Dg!  
;k9 ?  
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Utility.log("Thread " + nThreadID + " is over!"); p:DL:^zx  
bDownOver = true; Y}Am
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//nPos = fileAccessI.write (b,0,nRead); 3!i.Fmo  
} Gg 7WmL  
catch(Exception e){e.printStackTrace ();} jA20c(O  
} .OVW4svX  
} AZh@t?)  
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P5'iYahCq_  
//打印回应的头信息 XkMs
  
public void logResponseHead(HttpURLConnection con) i_j9/k  
{ b:N^Fe
 
for(int i=1;;i++) ioE66-n  
{ +)/Rql(lY  
String header=con.getHeaderFieldKey(i); 08TaFzP81  
if(header!=null) !!?+M @  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Y|{r vBKjf  
Utility.log(header+" : "+con.getHeaderField(header)); `_
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else >yV)d/  
break; T0@](g  
} W?*Xy6",JF  
} aukk|/3Ih  
[@,OG-"&  
/>dB%*  
public void splitterStop() r1[E{Tpz  
{ RB S[*D  
bStop = true; ,pQ'w7  
} 3::3r}g  
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} {]t\`fjrg  
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/* viW~'}^k7  
**FileAccess.java mF6@Y[/B  
*//文件访问(定位，写) *G%1_   
package NetFox; !ol hZ  
import java.io.*; 4A\BGD*5  
9f\aoVX  
OqfhCNAY  
public class FileAccessI implements Serializable{ Bo\a  
WUE)SVf  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^kCk^D-Gz  
RandomAccessFile oSavedFile; -XS+Uv  
long nPos; KKx&UKjV  
e3yorQ][  
5PPPd-'Z_  
public FileAccessI() throws IOException _H~p
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{ @Og\SZhn  
this("",0); @{J!6YGh  
} x&hvFG3  
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OPvj{Dv$0  
public FileAccessI(String sName,long nPos) throws IOException d-6sC@PB  
{ 2ru*#Z#(  
oSavedFile = new RandomAccessFile(sName,"rw"); aGq_hP   
this.nPos = nPos; B)j`}7O06  
oSavedFile.seek(nPos); ]Ks]B2Osz  
} aJuj7y-  
<3SFP3^:  
2
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public synchronized int write(byte[] b,int nStart,int nLen) HMEs8.  
{ ?G~/{m.  
int n = -1; WrE-Zti  
try{ o1 hdO  
oSavedFile.write(b,nStart,nLen); {#dp-5V  
n = nLen; .c=$ bQ>^  
} u%+6Mp[E  
catch(IOException e) jQ.>2-;H9  
{ !u
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e.printStackTrace (); Lu8%qcC  
} 'Yaf\Hp  
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return n; IEno.i\  
} >\6jb&,%O  
I,],?DQX2)  
6i9Q,4~  
} 0UM@L }L  
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/* Hm+6QgCs  
**SiteInfoBean.java ZXssvjWQV}  
*/ 4*N@=v  
package NetFox; [3{:H"t  
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/?.r!Cp  
public class SiteInfoBean { JqVBT+:  
2-"Lxe65f  
3oppV_^JdT  
private String sSiteURL; //Site's URL /ctaAQDUh\  
private String sFilePath; //Saved File's Path s]nGpA[!  
private String sFileName; //Saved File's Name C;58z5*,  
private int nSplitter; //Count of Splited Downloading File <eud#v  
Y5h)l<P>B  
]HNT(w@  
public SiteInfoBean() )M&Azbu  
{//nSplitter的缺省值为5 *7xQp!w^  
//default value of nSplitter is 5 >+A1 V[  
this("","","",5); +,vJ7  
} N8DiEB3~  
{Gk}3u/  
uNPD~TYN  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $+!}Vtb  
{ n3HCd-z  
sSiteURL= sURL; *hk{q/*Qw  
sFilePath = sPath; k2_6<v Z  
sFileName = sName; MQ9M%>
 
this.nSplitter = nSpiltter; |h^G$guw  
vjs|!O=oH  
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} H649J)v+m  
evndw>  
t(z(-G|&  
public String getSSiteURL() ^V
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{ n7`.<*:  
return sSiteURL; Sq?6R}q%  
} >n$EeJ  
IxEQh)J X  
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public void setSSiteURL(String value) WRLu3nBx  
{ |04}zU%N  
sSiteURL = value; Q8DQ .C  
} %WJ{IXlz  
bY"eC i{K  
Ol/2%UJXL  
public String getSFilePath() W)$|Hm:H  
{ 5x1%o
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return sFilePath; cOZajC<G  
} 9|G=KN)P:  
"b1R5
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public void setSFilePath(String value) ^;bGP.!p  
{ 35@Ibe~  
sFilePath = value; ',J%Mv>Yf  
} -?%{A%'  
M$>WmG1~D  
1^WA  
public String getSFileName() QX.F1T2e?  
{ t;e]L'z@:  
return sFileName; _,K>u6N&  
} H~_^w.P  
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public void setSFileName(String value) N8L)KgM5#7  
{ *]>OCGsr  
sFileName = value; [hv3o0".  
} n_xQSVI0F  
.2(@jx,[  

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public int getNSplitter() qRP8dH  
{ 9TX
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return nSplitter; cVP49r}}v  
} |$|nV^y  
*2m&?,nJ  
d~z<,_r5c  
public void setNSplitter(int nCount) 7zP  
{ /xrq'|r?C  
nSplitter = nCount; /J9T
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} "` ?Wu  
} rfZ
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RQK**  
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/* ~RR_[t2Z  
**Utility.java EH!EyNNb  
*/ =VX<eV  
package NetFox; @=zBF'<.9  
}~\].I6  
;uA_gn!  
public class Utility { 1Sc~Vb|>  
`bt)'ERO%#  
.+JPtL  
public Utility() kmwrv -W  
{ L&gEQDPgq|  
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} >G3J3P(  
OTFu4"]M  
//线程睡眠 o}^vREO  
public static void sleep(int nSecond) I3E8vi%B.  
{ iDkWW  
try{ `bi_)i6Low  
Thread.sleep(nSecond); fPk9(X;G!p  
} b8b PK<  
catch(Exception e) ``YL] <<  
{ B43#9CK`o  
e.printStackTrace (); szsZFyW)+  
} ,LPFb6o  
} zH\;pmWiN9  
uF.\dY\xv  
//日志 r0$9c  
public static void log(String sMsg) TI7Ty+s  
{  /qQ2@k  
System.err.println(sMsg); ]#7Y@Yo  
} 4[EO[x4C  
v%8-Al^G  
ThQEQ6y  
public static void log(int sMsg) Ynh4oWUp  
{ {^19.F  
System.err.println(sMsg); kA:;c}p  
} L!8?2 \5  
} W2.1xNWO  
6pz:Lfd80  
AU?YZEAei  
/* Ug'nr  
**TestMethod.java uu/7Ie  
*/ 0@/E%T1c"  
package NetFox; .S
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NwuBe:"@  
au}0PnA;  
public class TestMethod { @/2wmza%2  
E#V-F-@2  
FCB/FtI0  
public TestMethod() ghO//?m  
{ ///xx/weblogic60b2_win.exe z^HlDwsbm  
try{ 8RT0&[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);
0}C}\1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ps;o[gB@5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); jxOVH+?l%  
fileFetch.start(); nhxd
 
} K[;,/:Y  
catch(Exception e){e.printStackTrace ();} U[ O!&:6  
^EBM;&;7  
3UtXxL&L`  
} y?4=u,{C  
p`.fYW:p  
cZ2, u,4  
public static void main(String[] args) iwTBE]J  
{ BL^Hj  
new TestMethod(); PaI63 !  
} o|n0?bThS-  
}  hahD.P<  
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