http断点续传简单实现（java)

/* 5M~\'\;  
**SiteFileFetch.java <dzE5]%\  
*/ Xv'M\T}6C+  
package NetFox; bf `4GD(  
import java.io.*; _?3bBBy  
import java.net.*; bgd1j,PWbW  
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public class SiteFileFetch extends Thread { G1Cn[F;e  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "6n~,$  
long[] nStartPos; //开始位置 Pb.-Z@  
long[] nEndPos; //结束位置 A8OV3h6]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 S*:b\{[f>  
long nFileLength; //文件长度 ;""V s6  
boolean bFirst = true; //是否第一次取文件 CCX\"-C  
boolean bStop = false; //停止标志 ]7ROCJ;  
File tmpFile; //文件下载的临时信息 77OH.E|$  
DataOutputStream output; //输出到文件的输出流 Xb42R1  
"j9,3yJT  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） QhK]>d.  
public SiteFileFetch(SiteInfoBean bean) throws IOException "7RQrz  
{ C}+w<  
siteInfoBean = bean; jd=k[Yqr  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); O'" &9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v\t$. _at  
if(tmpFile.exists ()) r}9qK%C G.  
{ MZE8Cvq0  
bFirst = false; x<"e} Oo  
read_nPos(); k:<yy^g$X  
} TC3xrE:U<m  
else y1/$dn  
{ Fp-d69Npo  
nStartPos = new long[bean.getNSplitter()]; `w]=xe  
nEndPos = new long[bean.getNSplitter()]; VVvV]rU~  
} F`U%xn,  
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} H(!)]dO  
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public void run() 6.2_UN^<  
{ 1,Uv;s;{  
//获得文件长度 nvxftbfE^D  
//分割文件 ju(&v*KA  
//实例FileSplitterFetch k#ED#']N  
//启动FileSplitterFetch线程 IC/'<%k  
//等待子线程返回 $TL~SVHj;{  
try{ Sq}hx  
if(bFirst) H |Z9]+h)7  
{ Z= dEk`  
nFileLength = getFileSize(); 'i{kuTv  
if(nFileLength == -1) v$w!hYsQ  
{ fC2e}WR
  
System.err.println("File Length is not known!"); ;_,=  
} I)]wi%  
else if(nFileLength == -2) GrW+P[j9  
{ <u*~RYA2  
System.err.println("File is not access!"); 'AE)&56  
} %w,  
else v1QE|@  
{ &|IY=$-  
for(int i=0;i<nStartPos.length;i++) ^{_`jE  
{ <jQ?l%\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9@#Z6[=R,  
} u}JL*}Q  
for(int i=0;i<nEndPos.length-1;i++) ^LE`Y>&m  
{ j\("d4n%C  
nEndPos = nStartPos[i+1]; $OHY^IE(  
} #]oVVf_  
nEndPos[nEndPos.length-1] = nFileLength; YL=?Nk/  
} AM1J ^Dp  
} A}FEM[2  
^* ^te+N  
A{Z=[]r1`E  
//启动子线程 d3+pS\&IX?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [P]zdw w#  
for(int i=0;i<nStartPos.length;i++) :O{`!&[>L  
{ ync2X{9D  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9Y- Sqk+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), D:U:( pg  
nStartPos,nEndPos,i); s@E"EWp0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YW}q@AY7  
fileSplitterFetch.start(); Bl2y~fCA  
} KTD# a1W  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =M>1;Qr<Z/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); +#}I^N  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", a=&a)FR  
nEndPos = " + nFileLength); =LL5E}xP  
// fileSplitterFetch[nPos.length-1].start(); ^1BQejD  
r;t0+aLc*  
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//等待子线程结束 PGsXB"k<8  
//int count = 0; "D'A7DA  
//是否结束while循环 .dt7b4.kd  
boolean breakWhile = false; #Sr_PEo _  
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while(!bStop) x1W<r)A )r  
{
}
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write_nPos(); d_BECx<\  
Utility.sleep(500); Eg-3GkC  
breakWhile = true; B\wH`5/KW  
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for(int i=0;i<nStartPos.length;i++) r`pg`ChHv  
{ %<CahzYc6  
if(!fileSplitterFetch.bDownOver) W
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{ _(&^M[O  
breakWhile = false; QU_O9 BN  
break; N W :_)1  
} oJ\UF S  
} '3O@Nxof4  
if(breakWhile) ^6bU4bA  
break; w7cciD|  
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//count++; iY1%"x  
//if(count>4) <UOx>=h  
// siteStop(); m!3b.2/h  
} 1P:r=Rt/  
`=g9Rg/<  
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System.err.println("文件下载结束！"); T$5u+4>"  
} i\lur ET  
catch(Exception e){e.printStackTrace ();}
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} aN?{MA\  
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//获得文件长度 5@ecZ2`)+h  
public long getFileSize() 55MrsiW  
{ u[q1]]  
int nFileLength = -1; l2QO\O I9m  
try{ ]fvU}4!  
URL url = new URL(siteInfoBean.getSSiteURL()); 4nQk*:p(X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =p,+a/*  
httpConnection.setRequestProperty("User-Agent","NetFox"); WL$nchS9  
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int responseCode=httpConnection.getResponseCode(); 8d|omqe~P  
if(responseCode>=400) ^-?5=\`5  
{ S=H<5*]g  
processErrorCode(responseCode); ++n"` ]o,  
return -2; //-2 represent access is error 6nqG;z-IXJ  
} ,#3u.=IR[  
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String sHeader; 4A6D>ChB'E  
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for(int i=1;;i++) )nmLgsg  
{ ):OGhW
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 86igP  
//Utility.log(in.readLine()); ~CiVLSH=  
sHeader=httpConnection.getHeaderFieldKey(i); ~L$B]\/A5  
if(sHeader!=null) _i{$5JJ+K2  
{ S`HshYlE q  
if(sHeader.equals("Content-Length")) m99j]wr~c  
{ =!u9]3)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Rj 2N+59rg  
break; /cHd&i,>  
} [lZo'o  
} SQ!wq  
else ^Yz.,!B[  
break;  $0>>Z  
} GWo^hIfJ  
} sf
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catch(IOException e){e.printStackTrace ();} eAKK uML  
catch(Exception e){e.printStackTrace ();} R|aA6} /I  
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Utility.log(nFileLength); '{=dEEi  
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return nFileLength; mi9BC9W(  
} "Y0:Y?Vz"  
*)0bifw$&  
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//保存下载信息（文件指针位置） &Fo)ea  
private void write_nPos() PhBdm'  
{ q>:>f+4  
try{ 7 j$ |fS  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ;AyE(|U+  
output.writeInt(nStartPos.length); W/_=S+CvK  
for(int i=0;i<nStartPos.length;i++) F[PIo7?K  
{ [<SM*fQ>t  
// output.writeLong(nPos); \`?#V xz  
output.writeLong(fileSplitterFetch.nStartPos); .3WDtVE  
output.writeLong(fileSplitterFetch.nEndPos); EWuuNf  
}
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output.close(); _/;k;$gDp  
} &'`q&U1x  
catch(IOException e){e.printStackTrace ();} Vj?{T(K1[  
catch(Exception e){e.printStackTrace ();} M`IiK+IoU  
} E^uau=F  
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//读取保存的下载信息（文件指针位置） lrSdFJ%  
private void read_nPos() BG:l Zj'I  
{ 6&/H XqP  
try{ F02S(WWo;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); b]S4\BBT  
int nCount = input.readInt(); [pMJ9 d$  
nStartPos = new long[nCount]; xbJ@z{  
nEndPos = new long[nCount]; Wy^43g38'p  
for(int i=0;i<nStartPos.length;i++) _22;hnG<iy  
{ me]O  
nStartPos = input.readLong(); 9F+i+(\,b  
nEndPos = input.readLong(); mNkS!(L6  
} ,4dES|)sP  
input.close(); }G^Bc4@b  
} 0CXh|AU  
catch(IOException e){e.printStackTrace ();} p\lS)9  
catch(Exception e){e.printStackTrace ();} S%KY%hUt  
} *p!K9$4  
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private void processErrorCode(int nErrorCode) W\09hZ
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{ r~q*E'n  
System.err.println("Error Code : " + nErrorCode); s+Qm/ h2  
} Mazjn?f  
}`k >6B  
J }izTI  
//停止文件下载 jU')8m[  
public void siteStop() +$i-"^  
{ ,arFR'u>  
bStop = true; _r!''@B  
for(int i=0;i<nStartPos.length;i++) o6f^DG3*  
fileSplitterFetch.splitterStop(); w)I!q&`Y  
=6j4_+5mnH  
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} s8w7/*<d  
} -:9E+b  
//负责部分文件的抓取 ~F7 +R   
**FileSplitterFetch.java fdr.'aMf%  
*/ # Sfz^  
package NetFox; BNU]NcA#*,  
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import java.io.*; MGn:Gj"d  
import java.net.*; O+Z[bis`  
h
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public class FileSplitterFetch extends Thread { (QQ/I;  
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String sURL; //File URL 3md yY\+&  
long nStartPos; //File Snippet Start Position P;jl!o$  
long nEndPos; //File Snippet End Position E<]l]?  
int nThreadID; //Thread's ID ?>47!):-*  
boolean bDownOver = false; //Downing is over #"|Y"#@k  
boolean bStop = false; //Stop identical 0ZQ|W%tS  
FileAccessI fileAccessI = null; //File Access interface y7M"Dr%t^  
`5}XmSJ?5  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ju8mO&  
{ =x "N0p  
this.sURL = sURL; 2!QS&i  
this.nStartPos = nStart; ?_9cFo59:  
this.nEndPos = nEnd; | >xUgpQi  
nThreadID = id; :CEhc7gU  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >W2Z]V  
} G hH0-g{-  
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public void run() d!) &@k  
{ ,sPsL9]$  
while(nStartPos < nEndPos && !bStop) rtcY(5Q  
{ 9ls<Y  
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v ?@Ys+V  
try{ H?8uy_Sc  
URL url = new URL(sURL); \~ O6S`,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2d+IROA  
httpConnection.setRequestProperty("User-Agent","NetFox"); )W9$_<Z  
String sProperty = "bytes="+nStartPos+"-"; @ -pi  
httpConnection.setRequestProperty("RANGE",sProperty); CFD& -tED&  
Utility.log(sProperty); p1t9s N,  
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InputStream input = httpConnection.getInputStream(); u->UV:
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//logResponseHead(httpConnection); ]D&$k P(  
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k^I4z^O=-;  
byte[] b = new byte[1024]; D6Ov]E:fa  
int nRead; j
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) d|Wpub  
{ cw#p!mOi~  
nStartPos += fileAccessI.write(b,0,nRead); 7V?]Qif~  
//if(nThreadID == 1) H~RWM'_  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2&fIF}vk>m  
} vW6Pf^yJ  
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Utility.log("Thread " + nThreadID + " is over!"); Er} xB~<t  
bDownOver = true; '3=[xVnv  
//nPos = fileAccessI.write (b,0,nRead); Uxx=$&#  
} -WP_0  
catch(Exception e){e.printStackTrace ();} qNER 6  
} Q%~b(4E^7P  
} {>>ozB.  
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//打印回应的头信息 8^ju=  
public void logResponseHead(HttpURLConnection con) w#k'RuOw5  
{ QFIdp R.  
for(int i=1;;i++) X tZ0z?  
{ g<oSTAw  
String header=con.getHeaderFieldKey(i); y]eH@:MJ;A  
if(header!=null) hfP}+on%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); # 4`*`)%  
Utility.log(header+" : "+con.getHeaderField(header)); 3EB8ls2  
else 1R9hA7y&,/  
break; LoUi Yf  
} C)`ZI8  
} |mV*HdqU  
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LKY4rY!|@d  
public void splitterStop() MdT'xYomzQ  
{ tDFN *#(  
bStop = true; 2Xk(3J!!'a  
} F>&Q5Kl R  
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} ]hTYh^'e  
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)K>XLaG)  
/* x-) D@dw<  
**FileAccess.java \^SL Zhe  
*//文件访问(定位，写) a^i`DrX  
package NetFox; yyxGVfr  
import java.io.*; ZN5\lon|Y  
ftF?T.dx  
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public class FileAccessI implements Serializable{ By6C+)up  
NZYtA7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节
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RandomAccessFile oSavedFile; 7qA);N  
long nPos; K97lP~Hu  
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public FileAccessI() throws IOException 1t=Y+|vA9  
{ ^*'|(Cv  
this("",0); j#y_#  
} z^I"{eT8  
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public FileAccessI(String sName,long nPos) throws IOException ~ C6<75  
{ 9+h9]
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oSavedFile = new RandomAccessFile(sName,"rw"); 8e)k5[\m  
this.nPos = nPos; j2deb`GD  
oSavedFile.seek(nPos); 6'395x_.\  
} K+Al8L?K_  
"cRc~4%K  
u].=b$wHHM  
public synchronized int write(byte[] b,int nStart,int nLen) eV^@kI4  
{ O[y.3>l[s  
int n = -1;  IPa08/  
try{ LslQZ]3MY  
oSavedFile.write(b,nStart,nLen); o %A4wEye  
n = nLen; lYT}Nc4"="  
} CjORL'3  
catch(IOException e) :2Qm*Y&_$V  
{ `23&vGk}  
e.printStackTrace (); )y'`C@ijI  
} r vVU5zA4H  
p=\DZU~1  
8,=Ti7_  
return n;  a)PBC{I  
} 8^&)A b  
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} -'3vQXj&  
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t  
s ,\w00-:  
/* rw8O<No4.o  
**SiteInfoBean.java zA9N<0[]o  
*/ 4O9HoX#-?  
package NetFox; vLDMa>  
511^f`P<  
a+)Yk8%KY  
public class SiteInfoBean {  Usk@{  
RPPxiYU^  
EK_NN<So#  
private String sSiteURL; //Site's URL ii2X7Q  
private String sFilePath; //Saved File's Path =r3Yt9  
private String sFileName; //Saved File's Name \K`AO{ D@  
private int nSplitter; //Count of Splited Downloading File huWUd)Po%  
r.xGvo{iY  
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public SiteInfoBean() bPC {4l  
{//nSplitter的缺省值为5 fC.-* r  
//default value of nSplitter is 5 - 4'yp  
this("","","",5); dwv xV$Nt  
} m
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7.CzS  
{ '`T.K<  
sSiteURL= sURL; [esjR`u  
sFilePath = sPath; K_Y0;!W  
sFileName = sName; kWjCSC>jA  
this.nSplitter = nSpiltter; Ko\m8\3?fK  
[X
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} ^>h
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public String getSSiteURL() 9Vxsv*OR,  
{ QKCc5  
return sSiteURL; o ]2=5;)  
} 3*CF!Y%  
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$V]D7kDph*  
public void setSSiteURL(String value)  h#^I
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{ Dgj`_yd  
sSiteURL = value; j8M}
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} Os*,@N3t  
w?Nvm?_]  
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public String getSFilePath() NAZxM9  
{ _T6WA&;8  
return sFilePath; 7Nh6 `  
} LV0g *ng  
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public void setSFilePath(String value) 6f?5/hq  
{ 2etcSU(y>  
sFilePath = value; 702&E(rx,  
} !R//"{k0?  
k^ B'W{  
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public String getSFileName() |ZJ]`qmZ  
{ isj<lnQ  
return sFileName; i'L7t!f}o  
} 8niQG']  
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public void setSFileName(String value) M86
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{ TA`*]*O(  
sFileName = value; b?CmKiM%  
} /]>&OSV  
\kzxt/Ow  
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public int getNSplitter() ti`
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{ \$VtwVQ,b  
return nSplitter; Z2P
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} 59$mfW o>  
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public void setNSplitter(int nCount) 9gn_\!Mp  
{ >J3N,f  
nSplitter = nCount; Mn7 y@/1  
} y`mEs
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} "2'nLQ""q  
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/* n1y#gC  
**Utility.java zXbTpm  
*/ A}~hc&J  
package NetFox; n4>
 
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public class Utility { 8$v17 3  
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public Utility() q_OIzZ@  
{ me1ac\  
qoB  
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} #MHnJ  
#
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//线程睡眠 x2Y1B  
public static void sleep(int nSecond) V/"0'H\"1  
{ d+fmVM?p  
try{ A. U<  
Thread.sleep(nSecond); aZ*b"3  
} 1 YMaUyL 1  
catch(Exception e) X[j4V<4O  
{ u\^<V)  
e.printStackTrace (); : 60PO  
} ;)0vxcMB  
} c*~/[:}  
"!p#8jR^  
//日志 jn]hqTy8  
public static void log(String sMsg) ?7^('  
{ s3g$F23  
System.err.println(sMsg); |A'8'z&q  
} XLqS{r~?  
H$(%FWzQ%  
w,eYrxR|N  
public static void log(int sMsg) H!Uy4L~>  
{ b[GZ sXD-  
System.err.println(sMsg); *r:8=^C7S  
} bxkp9o  
} S.t+HwVodO  
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~;UK/OZ  
/* _m3PAD4  
**TestMethod.java %?X~,  
*/ iP|h];a+@  
package NetFox; $o/?R]h  
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public class TestMethod { m[ay  
Z(/jQ=ozQ  
P~ffgzP  
public TestMethod() ll[U-v{  
{ ///xx/weblogic60b2_win.exe jl3RE|M\<  
try{ .[= 0(NO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); U>:CX XHRt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); N=tyaS(YJ
 
SiteFileFetch fileFetch = new SiteFileFetch(bean);  $Jb+}mlT  
fileFetch.start(); L)8;96  
} lG%oqxJ+ L  
catch(Exception e){e.printStackTrace ();} ln9MVF'!&  
d?b2jZ$r]  
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} cU%#oEMf<  
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public static void main(String[] args) ;P5\EJo  
{ dlJkxEh2  
new TestMethod(); Sh2q#7hf  
}
|=N8X  
} il5WLi;{  
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