http断点续传简单实现（java)

/* dfnX!C~6\  
**SiteFileFetch.java oA[2)BU  
*/ - f+CyhR"*  
package NetFox; k#BU7Exij  
import java.io.*; (]oFB$  
import java.net.*; Af$0 o=".  
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public class SiteFileFetch extends Thread { oK%K+h  
#xDDh`  
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SiteInfoBean siteInfoBean = null; //文件信息Bean ~rp.jd 0l  
long[] nStartPos; //开始位置 iFY]0@yt  
long[] nEndPos; //结束位置 zR_9D}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `;R|V  
long nFileLength; //文件长度 <ihhV e  
boolean bFirst = true; //是否第一次取文件 Gt?!E6^!  
boolean bStop = false; //停止标志 H;4oZ[g  
File tmpFile; //文件下载的临时信息 uV/)Gb*j  
DataOutputStream output; //输出到文件的输出流 [<,0A]m   
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） *vEU}SxRuv  
public SiteFileFetch(SiteInfoBean bean) throws IOException xtG)^x!  
{ $eTv6B?m  
siteInfoBean = bean; }Z<D^Z~w  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); r@\,VD6J  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); g4
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if(tmpFile.exists ()) DX7Ou%P,mg  
{ 8s\8`2=  
bFirst = false; K#%O3RRs  
read_nPos(); qFB9,cUqh  
} 8uD8or  
else RRK^~JQI.2  
{ Mp}!+K  
nStartPos = new long[bean.getNSplitter()]; iG?w;  
nEndPos = new long[bean.getNSplitter()]; q_OY sg  
} })h'""i&xn  
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7?  
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} PTfN+  
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public void run() Z_ iQU1  
{ 7R% PVgS4x  
//获得文件长度 rcD.P?"  
//分割文件 eA;j/&qH  
//实例FileSplitterFetch iPR!JX _  
//启动FileSplitterFetch线程 zzDNWPzsA  
//等待子线程返回 e)fJd*P  
try{ HPv&vdr3  
if(bFirst) %`t]FV^#  
{ 9u-M! $  
nFileLength = getFileSize(); i!/h3%=  
if(nFileLength == -1) .2 N_?
  
{ 7=9A_4G!  
System.err.println("File Length is not known!"); )eIz{Mdp=  
} eWq
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else if(nFileLength == -2) 0jl:Yzo&\  
{ RBMMXJ
j  
System.err.println("File is not access!"); N?Z+zN&P  
} U~JG1#z6  
else %FXIlH
5
 
{ 2`q^Q  
for(int i=0;i<nStartPos.length;i++) 4okHAv8;  
{ LrmtPnL  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); fS8XuT  
} _ d(Ks9  
for(int i=0;i<nEndPos.length-1;i++) v ](G?L9b  
{ i75?*ld  
nEndPos = nStartPos[i+1]; `"^@[1  
} .~V".tZV[  
nEndPos[nEndPos.length-1] = nFileLength; x0TnS#  
} 3\+[38 _  
} VdjU2d  
;'Z,[a  
{!:|.!-u  
//启动子线程 P %U9S  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 6w:g77SH)%  
for(int i=0;i<nStartPos.length;i++) 4q@9  
{ ZIGbwL  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^HOwN<}`#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ZipK;!9by  
nStartPos,nEndPos,i); VLwJ6?.f'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ePu2t3E  
fileSplitterFetch.start(); Y;%R/OyWY  
} ajcPt]f  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OmoplJ+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); pE YrmC  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lL(}dbT~N  
nEndPos = " + nFileLength); 80R=r  
// fileSplitterFetch[nPos.length-1].start(); +lXdRc`6  
qAuUe=w%p  
=_H*fhXS  
//等待子线程结束 " N`V
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//int count = 0; %3@RZe  
//是否结束while循环 cE_Xo.:Y,  
boolean breakWhile = false; eW }jS/g`  
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while(!bStop) iX9[Q0g=oQ  
{ k*UR#z(I  
write_nPos(); 5G42vTDzS4  
Utility.sleep(500); ;]O 7^s#v  
breakWhile = true; Rp4BU"&sU  
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for(int i=0;i<nStartPos.length;i++) >> 8KL`l  
{ .ON$vn7  
if(!fileSplitterFetch.bDownOver) *|.y
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{ Ow&'sR'CX  
breakWhile = false; H?zCI
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break; *M**h-p2'  
} Kw5+4R(5  
} bju,p"J1-E  
if(breakWhile) +XaO?F[c  
break;  _c7  
~]t2?SqNm  
yI)RGOV  
//count++; (/rIodHJO  
//if(count>4) 3 v,ae7$U&  
// siteStop(); F" #3s=  
} ju2X*  
L^ jC& dF  
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System.err.println("文件下载结束！"); SJ|.% gn  
} 5IF~]5s  
catch(Exception e){e.printStackTrace ();} BX)cV  
} W~@GK  
 M$-(4 0  
yKk,);  
//获得文件长度
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public long getFileSize() B#V4  
{ m#}{"d&J  
int nFileLength = -1; GT`<jzAiQ  
try{ 0T{Y_IG  
URL url = new URL(siteInfoBean.getSSiteURL()); 9[]"%6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gQzJ2LU(  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0_xcrM  
bU +eJU_%  
J;]@?(  
int responseCode=httpConnection.getResponseCode(); NB6h/0*v  
if(responseCode>=400) #L*@~M^]  
{ $R#L@iL-  
processErrorCode(responseCode); :@4>}k*  
return -2; //-2 represent access is error r3bvuq,6$  
} A,CPR0g%  
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t;~`Lm@hY  
String sHeader; kGTc~p(  
Vgb>3]SU  
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for(int i=1;;i++) 3b/vyZF  
{ DDCQAf  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @IKe<{w  
//Utility.log(in.readLine()); 8LM1oal}  
sHeader=httpConnection.getHeaderFieldKey(i); C5n=2luI_
 
if(sHeader!=null) kAF}*&Kzd~  
{ )cmLo0`$  
if(sHeader.equals("Content-Length")) TXOW/{B  
{ M>z7H"jCu  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Q1&dB{L  
break; B+H9c~3$  
} r
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} \rnG 1o  
else FoXQ]X7"  
break; *L8HC8IbH  
} BNm va  
} Ol5xyj  
catch(IOException e){e.printStackTrace ();} }
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catch(Exception e){e.printStackTrace ();} 9TN
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Utility.log(nFileLength); &``oZvuB  
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return nFileLength; Ewsg&CCN  
} E&tmWOMj>  
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} K-[/;  
//保存下载信息（文件指针位置） pPoC61F  
private void write_nPos() ]M"'qC3g  
{ 2}C>{*}yQ  
try{ J0W).mD_H  
output = new DataOutputStream(new FileOutputStream(tmpFile)); TK?+O}v-]!  
output.writeInt(nStartPos.length); !OVEA^6  
for(int i=0;i<nStartPos.length;i++) kxf=%<l  
{ s^@Cq=  
// output.writeLong(nPos); +\$|L+@Z  
output.writeLong(fileSplitterFetch.nStartPos); ~TR|Pv  
output.writeLong(fileSplitterFetch.nEndPos); {hP&P  
} Ujzz`!mz  
output.close(); ? Z fhz  
} q;~>h  
catch(IOException e){e.printStackTrace ();} +((31l  
catch(Exception e){e.printStackTrace ();} Yf`.Cq_:  
} D ;I;,Z  
__%E!*m"<_  
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//读取保存的下载信息（文件指针位置） iC2n
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private void read_nPos() z(68^-V=:  
{ x`l; ;  
try{ {YTF]J$  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); kU>|E<c*  
int nCount = input.readInt(); trt\PP:H%  
nStartPos = new long[nCount]; V/%;:ul.  
nEndPos = new long[nCount]; ryLNMh  
for(int i=0;i<nStartPos.length;i++) |^{" 2l"j  
{ u(`A?H:  
nStartPos = input.readLong(); O!Cu.9}  
nEndPos = input.readLong(); r@UY$z  
} eH*b-H[  
input.close(); `bF;Ew;  
} 2![W N*N>O  
catch(IOException e){e.printStackTrace ();} &bK$!8Z  
catch(Exception e){e.printStackTrace ();} rM.<Gi05Qe  
} FQ1oqqr  
*lF%8k"Al  
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private void processErrorCode(int nErrorCode) Q8:ocEhR  
{ C>VZf,JE1  
System.err.println("Error Code : " + nErrorCode); x}j41E}  
} ^i1:PlW]  
Y &+/[[  
*lO+^\HXD  
//停止文件下载 Mwk_SCy  
public void siteStop() +Z]%@"S?  
{ ^C|9K>M  
bStop = true; _oVA0@#n  
for(int i=0;i<nStartPos.length;i++) 6^u(PzlA|~  
fileSplitterFetch.splitterStop(); 5)<jP
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} MX\-)e#  
} xhS/X3<th  
//负责部分文件的抓取 ENjD~S  
**FileSplitterFetch.java 2=+ ,jX{  
*/ EIm\!'R]  
package NetFox; R?SHXJ%'  
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import java.io.*; AE _~DZ:%c  
import java.net.*; dig76D_[e  
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public class FileSplitterFetch extends Thread { >L4$DKO  
/MtacR  
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String sURL; //File URL ob #XKL  
long nStartPos; //File Snippet Start Position FR"^?z
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long nEndPos; //File Snippet End Position Xy&#}S}9  
int nThreadID; //Thread's ID Z+7S,M  
boolean bDownOver = false; //Downing is over [.,6~=}vP  
boolean bStop = false; //Stop identical ir#^5e@  
FileAccessI fileAccessI = null; //File Access interface vn0*KIrX  
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u;}B4Rx
  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException S}O\<6&  
{ hDsORh!i  
this.sURL = sURL; #Qd3
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this.nStartPos = nStart; 3Gv i!h7  
this.nEndPos = nEnd; &X(-C9'j  
nThreadID = id; 
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 4*W7{MPY  
} 4iW2hV@m  
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public void run() `I$A;OPK7  
{ =1capix 1r  
while(nStartPos < nEndPos && !bStop) !o!04_  
{ gs>cx]>  
)_?$B6hf,&  

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try{ Um<vs
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URL url = new URL(sURL); -Ma"V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); tEs$+b  
httpConnection.setRequestProperty("User-Agent","NetFox"); v g]&T  
String sProperty = "bytes="+nStartPos+"-"; p6)UR~9Rs  
httpConnection.setRequestProperty("RANGE",sProperty); p<e~x/@m*  
Utility.log(sProperty); m Y0C7i  
v2V1&-
  
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InputStream input = httpConnection.getInputStream(); .YRSd  
//logResponseHead(httpConnection); (6{ VMQ  
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byte[] b = new byte[1024]; M-gjS6c\3  
int nRead; 8>9+w/DL  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) p%-9T>og  
{ !TFVBK  
nStartPos += fileAccessI.write(b,0,nRead); L')zuI  
//if(nThreadID == 1) <9~qAq7^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); aJ5R
0Y,  
} %ZK}y{u\  
=qRVKz  
(1^(V)@  
Utility.log("Thread " + nThreadID + " is over!"); |*$_eb  
bDownOver = true; tDo0Q/`  
//nPos = fileAccessI.write (b,0,nRead); ;+U9;  
} T_WQzEL^  
catch(Exception e){e.printStackTrace ();} UsTPNQj  
} /rW{rf^  
} <4g^c&  
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//打印回应的头信息 _c2#  
public void logResponseHead(HttpURLConnection con) ;l'I.j  
{ !MC Wt  
for(int i=1;;i++) ]O."M"B  
{ ?*4zNhL  
String header=con.getHeaderFieldKey(i); "^H+A-R[  
if(header!=null) zjmc>++<t  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xcig'4L  
Utility.log(header+" : "+con.getHeaderField(header)); v6:DA#0  
else u#\3T>o%@  
break; $$@Tgkg?o  
} ? &O$ayG77  
} &ly[mBP~  
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public void splitterStop() ,#G@ri:B  
{  pK4)>q  
bStop = true; _OY;SJ(  
} 5IMH G%W7  
E !8y|_(j  
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} 4jpF^&y7u^  
:.cX3dP@  
/ @&Sqv4?  
/* i,'~Ds  
**FileAccess.java yrjm0BM#  
*//文件访问(定位，写) ;%1^k/b6t  
package NetFox; .<.qRq-  
import java.io.*; bA)Xjq)Rr  
^?2txLv,6  
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public class FileAccessI implements Serializable{ OH~t\fQ1Zf  
r!#3>
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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 *s^5BLI9  
RandomAccessFile oSavedFile; ZZTV >:  
long nPos; Lh}he

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wb}tN7~Y;  
F!xK#~e  
public FileAccessI() throws IOException sR6(8  
{ %_ ~[+~#  
this("",0); URAipLvN  
} YblRwic  
Y%faf.$/9  
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public FileAccessI(String sName,long nPos) throws IOException .#n?^73  
{ ?]t8$^m,;  
oSavedFile = new RandomAccessFile(sName,"rw"); V/Q6v YX  
this.nPos = nPos; /a q%l]hQ@  
oSavedFile.seek(nPos); vZ08/!n  
} 4Z_.Jdu w  
gvC2\k{  
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public synchronized int write(byte[] b,int nStart,int nLen) 2C-u2;X2  
{ h2q]!01XP  
int n = -1;  rLwc=(|  
try{ ; H3kb +  
oSavedFile.write(b,nStart,nLen); #'T|,xIr-Q  
n = nLen; /$n${M5!  
} 8X%;29tow  
catch(IOException e) $\bH5|Hk]  
{ @:[/uqL  
e.printStackTrace (); U0rz 4fxc  
} &^<94l  
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+|.#<]GA  
return n; {b?)|@)is  
} F JzjS;  
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} 0h7\zoZ5  
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/* Cxh9rUe.  
**SiteInfoBean.java MwuH.# Ez  
*/ HV sIbQS  
package NetFox; /90@ 85%r  
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public class SiteInfoBean { b,cvQD  
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private String sSiteURL; //Site's URL .,c8cq?  
private String sFilePath; //Saved File's Path ;7hf'k  
private String sFileName; //Saved File's Name rdK.*oT  
private int nSplitter; //Count of Splited Downloading File PQ
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v uJ~Lg{  
}$7Hf+G  
public SiteInfoBean() {*|y
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{//nSplitter的缺省值为5 mz#(\p=T  
//default value of nSplitter is 5
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this("","","",5); %p
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} xpV8_Gz;  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) EGs z{c[8@  
{ q%JV"9,  
sSiteURL= sURL; ]\jhtC=2  
sFilePath = sPath; J@Li*Ypo  
sFileName = sName; vH?/YhH|  
this.nSplitter = nSpiltter; ss[8d%V  
%PG0PH4?  
0nv3JX^l]  
} G q8/xxt  
nK:39D$(  
)Q
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public String getSSiteURL() mV;7SBoT  
{ B^6P6,  
return sSiteURL; nB
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} BjB2YO& /  

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@<};Bo'  
public void setSSiteURL(String value) [iDa6mcth  
{ iBZ+gsSP  
sSiteURL = value; )N}xKw|  
} PKwx)! Rz  
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c`i
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public String getSFilePath() .D7\Hao  
{ I($u L@$  
return sFilePath; rf9RG!  
} #0mn_#-P)  
!0w'S>e  
uZqo"  
public void setSFilePath(String value) x$Lt?'  
{ qOng?(I  
sFilePath = value; <cl$?].RE!  
} ]AN)
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public String getSFileName() E=LaPjEIj  
{ 6!bf,T
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return sFileName; t rHj7Nw  
} p}j{<y  
I&^?,Fyy<  
5B(|!Xq;I  
public void setSFileName(String value) TzIgEn~  
{ p>MX}^6  
sFileName = value; !D  
} 'dx4L }d  
H\O|Y@uVr  
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public int getNSplitter() 
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{ D$j`+`  
return nSplitter; T*$uc,  
} K[ylyQ1  
oVLz7Y[JE  
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public void setNSplitter(int nCount) {xOu*8J  
{ B$7lL
  
nSplitter = nCount; <1hwXo  
} KKOu":b  
} GM@TWwG-B  
R,
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SBYRN##n_  
/* /R^!~J50  
**Utility.java s$RymM  
*/ 6jKM,%l  
package NetFox; YpuA,r;"  
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3lKIEPf6r  
public class Utility { ~)()PO  
)hn,rmn (P  
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public Utility() )`g[k"yB3  
{ &*0!${B  
of(Nq@  
[T
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} [t ^|l?  
`5>IvrzXrK  
//线程睡眠 JhuKW>7  
public static void sleep(int nSecond) "+|>nA=7  
{ J H$  
try{ Gk!v-h9cq  
Thread.sleep(nSecond); ;7qk9rz4  
} k5<lkC2z  
catch(Exception e) {V
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{ 5Lue.U%a  
e.printStackTrace (); 8l?]UFM>C  
} b#$:XS  
} 4$_8#wB1&  
'o5[:=K  
//日志 uD. 0?*_  
public static void log(String sMsg) IMVoNKW-  
{ ^\x PF5  
System.err.println(sMsg); C8(sH@  
} V @8X.R>  
lMP|$C  
\f._I+gJ  
public static void log(int sMsg) Wmp\J3  
{ 1AhL-Lj  
System.err.println(sMsg); J@1(2%)|Z  
} 9WBDSx_(Q  
} y 5=J6a2.  
!rrjA$P<v  
M`"2;  
/* W>+<r9Rt4  
**TestMethod.java c5U1N&k5&  
*/ 9N9|hy  
package NetFox; hf%W grO.  
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GZO,]%z  
public class TestMethod {  f0:)  
ZtIK"o-|!  
L@v0C)
  
public TestMethod() {x-
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{ ///xx/weblogic60b2_win.exe j^LnHVHk1  
try{ {qj>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); n NAJ8z}Nt  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fDqlN`P@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); smk0*m4  
fileFetch.start(); Ot v{#bB$  
} S$V'_  
catch(Exception e){e.printStackTrace ();} a3p|>M6E  
`.><$F  
k ^+h>B-;  
} .]8 Jeb  

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P^&+ehp  
public static void main(String[] args) )Q9J,  
{ CuDU~)`  
new TestMethod(); SR8[ 7MU  
} F[9IHT6{  
} SUx\
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