http断点续传简单实现（java)

/* %i.|bIhmm  
**SiteFileFetch.java bzJKoxU  
*/ 6:B5PJq  
package NetFox; A:D\!5=  
import java.io.*; V?_%Y<|L  
import java.net.*; 6,@M0CX  
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public class SiteFileFetch extends Thread { >hQR  
+vU.#C_2  
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SiteInfoBean siteInfoBean = null; //文件信息Bean +uT=Wb \  
long[] nStartPos; //开始位置 W/\7m\B  
long[] nEndPos; //结束位置 Ix(4<s  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 dHp6G^Y  
long nFileLength; //文件长度 L1F){8[  
boolean bFirst = true; //是否第一次取文件  vo::y"  
boolean bStop = false; //停止标志 il#rdJ1@t  
File tmpFile; //文件下载的临时信息 e<p$Op  
DataOutputStream output; //输出到文件的输出流 ?0?'  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） qHKZ5w  
public SiteFileFetch(SiteInfoBean bean) throws IOException Yt#($}p  
{ ko5\*!|:lj  
siteInfoBean = bean; w}YHCh  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )j9FB  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ]$L[3qA.  
if(tmpFile.exists ()) {>+$u"*  
{ 
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bFirst = false; RU{}qPs?  
read_nPos(); 1B1d>V$*  
} RF;N]A?*  
else B"qG-ci  
{ <;XJ::d  
nStartPos = new long[bean.getNSplitter()]; C$tSsw?A  
nEndPos = new long[bean.getNSplitter()]; "|Pl(HX  
} /C(L(
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} Z ZiS$&NK8  
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public void run() JNu- z:J  
{ S1B
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//获得文件长度 m_Rgv.gE^  
//分割文件 R80R{Ze  
//实例FileSplitterFetch y&CU
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//启动FileSplitterFetch线程 9.@(&  
//等待子线程返回 fC-^[Af)  
try{ p;5WLAF  
if(bFirst) b9YpUm7#  
{ +p[~hM6?  
nFileLength = getFileSize(); gO/(/e>P  
if(nFileLength == -1) eyE
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{ uVk8KMYU  
System.err.println("File Length is not known!"); \ bhok   
} Q
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else if(nFileLength == -2) ]u,~/Gy  
{ /Mk)H d  
System.err.println("File is not access!"); YL.z|{\e  
} h49Q2`  
else ]SPB c  
{ =&p
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for(int i=0;i<nStartPos.length;i++) G8&'*7Bb  
{ Yn#8uaU  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); PWmz7*/  
} F9<OKcXH  
for(int i=0;i<nEndPos.length-1;i++) Ya_6Zd4O  
{ roA1=G\Q  
nEndPos = nStartPos[i+1]; .( J/*H  
} Lm?*p>\Q  
nEndPos[nEndPos.length-1] = nFileLength; gctaarB&  
} Cm4*sN.&)  
} A1q^E(}O  
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jQb D2x6(  
//启动子线程 9PJDT]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Z C93C7lJ  
for(int i=0;i<nStartPos.length;i++) cOb%SC[A{  
{ mQs$7t[>t  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [z~Nw#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), zFn&~lFB  
nStartPos,nEndPos,i); `@M4THt  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Wa(S20yF  
fileSplitterFetch.start(); ]'Yw#YB  
} R u5&xIQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X{ =[q|P  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Ic}ofBK  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~Hs{(7  
nEndPos = " + nFileLength); dO[4}FZ$  
// fileSplitterFetch[nPos.length-1].start(); gp)ds^  
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Lm|X5RVq  
//等待子线程结束 X2[cR;;'  
//int count = 0; KV_Ga8hs  
//是否结束while循环 @"8QG^q8de  
boolean breakWhile = false; DKl7|zG4  
}/spo3,6  
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while(!bStop) b0X[x{k"  
{ 5B 7*Z  
write_nPos(); G C'%s  
Utility.sleep(500); !P$xh  
breakWhile = true; pCc7T-"og  
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2-0cB$W+  
for(int i=0;i<nStartPos.length;i++) mPin\-I  
{ B:~;7A\  
if(!fileSplitterFetch.bDownOver) \NU[DHrMP  
{ l;A_Aii(  
breakWhile = false; m;f?}z_\$  
break; }qhK.e  
} 5$U>M
 
} j\f$r,4  
if(breakWhile) *]WXM.R8  
break; LFyceFbm  
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1`lFF_stkP  
//count++; ~,2hP ~  
//if(count>4) ^4pKsO3ul  
// siteStop(); o2d~  
} L_"(A #H:  

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Ts .Zl{B  
System.err.println("文件下载结束！"); Ki/5xK=s  
} Xp6*Y1Y  
catch(Exception e){e.printStackTrace ();} 4QAIQQS  
} k!=GNRRZE  
r)(BT:2m  
ACO4u<M)  
//获得文件长度 VtiqAh}4  
public long getFileSize()  IB{ZE/  
{ WV1
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int nFileLength = -1; 6 v^  
try{ qLi9ym, ]  
URL url = new URL(siteInfoBean.getSSiteURL()); 8 QF?W{NK  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \.P}`Bpa  
httpConnection.setRequestProperty("User-Agent","NetFox"); G*i#\   
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^r*%BUU9]%  
int responseCode=httpConnection.getResponseCode(); NcBe|qxQ  
if(responseCode>=400) $H-D9+8 7  
{ MW$H/:3  
processErrorCode(responseCode); @
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return -2; //-2 represent access is error Q\#{2!I  
} H
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5  
)_*a7N!  
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String sHeader; H!r Kz  
=+}}Sv2  
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for(int i=1;;i++) I.+)sB?5  
{ cJ##K/es  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); k>&s(b  
//Utility.log(in.readLine()); P
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sHeader=httpConnection.getHeaderFieldKey(i); A?D"j7JD=L  
if(sHeader!=null) 0tCOb9  
{ &U$8zn~[k  
if(sHeader.equals("Content-Length")) 0IgnpeA]  
{ r@[VY g~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K=Z]#bm  
break; 0*Km}?;0-  
} `bZU&A(`Be  
} Fy@#r+PgWp  
else nj
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break; ccn
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} *76viqY;dE  
} _lPl)8k  
catch(IOException e){e.printStackTrace ();} ?3,
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catch(Exception e){e.printStackTrace ();} )n}]]^Sc  
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Utility.log(nFileLength); r` `iC5Ii  
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return nFileLength; R_>TEYZ  
} hG~]~ )  
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{nPkb5xbW  
//保存下载信息（文件指针位置） u@bOEcxK  
private void write_nPos() =F
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{ J`+`Kq1T  
try{ hGA!1a4 c  
output = new DataOutputStream(new FileOutputStream(tmpFile)); < [S1_2b.t  
output.writeInt(nStartPos.length); }.M
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for(int i=0;i<nStartPos.length;i++) -S,ir  
{ !/4V^H  
// output.writeLong(nPos); 1x\VdT  
output.writeLong(fileSplitterFetch.nStartPos); ! [|vx!p  
output.writeLong(fileSplitterFetch.nEndPos); ]~\SR0  
} hr
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output.close(); )-.Cne;n  
} k?["F%)I  
catch(IOException e){e.printStackTrace ();} ^%oG8z,L  
catch(Exception e){e.printStackTrace ();} LZQFj/,Jg  
} +f\pk \Ith  
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//读取保存的下载信息（文件指针位置） UN*dU  
private void read_nPos() pY)j0tdd  
{ jA-5X?!In  
try{ hmBnV  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g<2lPH  
int nCount = input.readInt(); r%y;8$/-  
nStartPos = new long[nCount]; mo|PrLV  
nEndPos = new long[nCount]; 7~kpRa@\P  
for(int i=0;i<nStartPos.length;i++) 4>$ ;gH  
{ ^p"4)6p-W  
nStartPos = input.readLong(); KkdG.c'  
nEndPos = input.readLong(); uP
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} hsHVX[<5`  
input.close(); D%jD8p  
} hi {2h04  
catch(IOException e){e.printStackTrace ();} _H4$$  
catch(Exception e){e.printStackTrace ();} \3Q:K|  
} +EST58  
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private void processErrorCode(int nErrorCode) =j|v0& AGC  
{ t,=@hs hN  
System.err.println("Error Code : " + nErrorCode); r,u<y_YW  
} (o x4K{  
2vqmsl?  
%A)-m 69  
//停止文件下载 mJ8{lXq3!  
public void siteStop() {t844La"  
{ bmj8WZ  
bStop = true; I~p8#<4#b  
for(int i=0;i<nStartPos.length;i++) Y!Uu173  
fileSplitterFetch.splitterStop(); PPwxk;  
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t$]&,ucW#  
} ,bZ"8Z"lss  
} qJ{r!NJJ 8  
//负责部分文件的抓取 _HWHQF7  
**FileSplitterFetch.java HA^jk%53  
*/ L4YVH2`0)  
package NetFox; JCw{ ?^F"  
#<a_: m)@  
)(h&Q? Ar  
import java.io.*; %~#!NX  
import java.net.*; Y!++CMzU  
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public class FileSplitterFetch extends Thread { <a8#0ojm  
WF ?/GN  
T!u'V'Ei2  
String sURL; //File URL qDby!^ryc  
long nStartPos; //File Snippet Start Position a. h?4+^bN  
long nEndPos; //File Snippet End Position xa87xX=a  
int nThreadID; //Thread's ID CrnB{Z4L  
boolean bDownOver = false; //Downing is over 
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boolean bStop = false; //Stop identical QD$}-D[  
FileAccessI fileAccessI = null; //File Access interface [c&2i`C  
hlAR[]  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException {PN:bb  
{ y#]}5gJ  
this.sURL = sURL; r?64!VS;  
this.nStartPos = nStart; Xtci0eS#V  
this.nEndPos = nEnd; )^t!|*1LA  
nThreadID = id; Ms.PO{wb  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P['X<
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} IXGW2z;  
[ 3$.*   
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public void run() 7*zB*"B'1t  
{ qTyg~]e9(  
while(nStartPos < nEndPos && !bStop) KK:N [x  
{ u$WBc\j  
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try{ ?Wwh _TO  
URL url = new URL(sURL); x Z|&/Ci  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =y?#^  
httpConnection.setRequestProperty("User-Agent","NetFox"); h6g=$8E  
String sProperty = "bytes="+nStartPos+"-"; sS C?io  
httpConnection.setRequestProperty("RANGE",sProperty); fph-v-cl  
Utility.log(sProperty); e Wc_N  
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InputStream input = httpConnection.getInputStream(); &(gm4bTg  
//logResponseHead(httpConnection); i4h

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byte[] b = new byte[1024]; aQ&uC )w  
int nRead; ;5<P|:^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 0r1g$mKb  
{ Xa4GqV9M/-  
nStartPos += fileAccessI.write(b,0,nRead); D^|jZOJ  
//if(nThreadID == 1) p?Z(rCp  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3f_i1|>)'  
} / >%L[RJ4  
a lrt*V|=  
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Utility.log("Thread " + nThreadID + " is over!"); Was'A+GZ  
bDownOver = true; |-|jf  
//nPos = fileAccessI.write (b,0,nRead); .\$Wy$ d  
} d&hD[v  
catch(Exception e){e.printStackTrace ();} L*P_vCC  
} }qG#N  
} _HwpPRVP/  
]22C)<  
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//打印回应的头信息 :#WEx_]  
public void logResponseHead(HttpURLConnection con) >b'w'"  
{ qB+n6y%  
for(int i=1;;i++) &(g|="T  
{ LaDY`u0G%  
String header=con.getHeaderFieldKey(i); 9J?W '8s5  
if(header!=null) P2Onkl  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); kg:l:C)Tq  
Utility.log(header+" : "+con.getHeaderField(header)); Te+^J8  
else 9GThyY  
break; 0Su_#".-*  
} N3ZiGD  
} \
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public void splitterStop() 58J_ w X  
{ IK3qE!,&U  
bStop = true; @.k5MOn  
} ^+M><jE9  
}
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} zwnw'  
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/* Z9xR  
**FileAccess.java D{R/#vM jk  
*//文件访问(定位，写) @m?{80;uQ  
package NetFox; >{QdMn  
import java.io.*; JPsSw  
*E}Oh  
9Fk4|+OJ  
public class FileAccessI implements Serializable{ %lV@:"G  
}C_
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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 ;,dkJ7M  
RandomAccessFile oSavedFile; iOll WkF  
long nPos; [%jxf\9jJ_  
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) oxIzF  
public FileAccessI() throws IOException QNb>rLj52  
{ dhW<p5  
this("",0); !_dR'  
} \dTQQ  
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public FileAccessI(String sName,long nPos) throws IOException ?gN9kd)  
{ R4SxFp  
oSavedFile = new RandomAccessFile(sName,"rw"); _jmkl B  
this.nPos = nPos; "7d.i(vw  
oSavedFile.seek(nPos); /1[gn8V691  
} 0V3gKd7  
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 g#qNHR  
public synchronized int write(byte[] b,int nStart,int nLen) P_}/#N{C  
{ 7b46t2W<  
int n = -1; y:,9I`aW  
try{ 8?1o<8hV  
oSavedFile.write(b,nStart,nLen); Mn@$;\:  
n = nLen; y AOg\+  
} "5}%"-#  
catch(IOException e) 61Bhm:O5W  
{ TP{Gt.e  
e.printStackTrace (); T(V8;!  
} s^cc@C  
d=y0yq{L  
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return n; w" JGO  
} 5oJ Dux }  
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} 4uUs7T  
<s}|ZnGE  
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/* sT`^ljp4  
**SiteInfoBean.java &K *X)DAs  
*/ hiwIWd:H  
package NetFox; %$TEDr!  
#Qd'+M  
k" YHsn  
public class SiteInfoBean { x@m<Ym-  
j{;|g%5t  
)* TF"  
private String sSiteURL; //Site's URL 5m7b\Mak  
private String sFilePath; //Saved File's Path QrC/ssf}  
private String sFileName; //Saved File's Name k_?~<vTM  
private int nSplitter; //Count of Splited Downloading File *b"CPg/\  
;'HF'Z  
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public SiteInfoBean() Yj|]Uff8O  
{//nSplitter的缺省值为5 x2k*|=$  
//default value of nSplitter is 5 Obo_YE  
this("","","",5); J>%t<xYf4  
} aD ESr?  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 6Y7H|>g)  
{ :6lwO%=F  
sSiteURL= sURL; yU7I;]YP  
sFilePath = sPath; k|FSz#Y  
sFileName = sName; Jq .L:>x  
this.nSplitter = nSpiltter; 5+K;_)   
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-=)-sm'  
} 2+'|kt2  
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public String getSSiteURL() hD q2-X}  
{ -eml  
return sSiteURL; .X'< D*  
} }fA;7GW+9  
?z=\Ye5x  
3taa^e.  
public void setSSiteURL(String value) (A{NF(   
{ r5 yO5W  
sSiteURL = value; Oq+E6"<y;?  
} B1$ikY  
vv.PF~:  
hCC}d0gf`n  
public String getSFilePath() =yqHC<8:  
{ l-O$m  
return sFilePath; T|){<  
} M+Uyb7  
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"(TkJbwC[  
public void setSFilePath(String value) g8pO Lr'  
{ ;JTt2qQKo  
sFilePath = value; M$S]}   
} \3zj18(@8!  
7y<1LQ;}  
:T@r*7hNT  
public String getSFileName() ejePDgi_[  
{ 
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return sFileName; +4)7j&L  
} #&Is GyU  
Hf
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public void setSFileName(String value) 9F##F-
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{ nCnjq=  
sFileName = value; )D@~|j:  
} E^V|  
6|;Uq'  
}nrXxfu  
public int getNSplitter() {aOkV::  
{ !xK=#pa  
return nSplitter; eSy(~Y
 
} [kB `  
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public void setNSplitter(int nCount) ?J!
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{ *yaw$oB  
nSplitter = nCount; *3+-W  
} ,/2LY4` 5  
} `jsEN ;<  
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/* gS9>N/b|  
**Utility.java gK1g]Tc@G  
*/ !iu5OX7K|  
package NetFox; |+f-h,  
P,z:Z|}8  
VLvS$0(}Z  
public class Utility { \
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{6,|IGAq V  
+RDJY(Y$  
public Utility() tw K^I6@  
{ ^twivNB  
+
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/b[2lTC-e  
} !{UTD+|=N  
*b|NjwmB  
//线程睡眠 Te
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public static void sleep(int nSecond) uofr8oL~  
{ 0!GAk  
try{ Jfhk@27T  
Thread.sleep(nSecond); v/QUjXB
r  
} ~^US/"  
catch(Exception e) &"E lm  
{ DSyXr~p8  
e.printStackTrace (); 5W? PCOh\  
} >FF5x#^&c  
} i'HQQWd  
QWO]`q`|  
//日志 w4};q%OBj  
public static void log(String sMsg) 1,t)3;o$  
{ _M5%V>HO  
System.err.println(sMsg); YZwaD b
 
} J7$_VP  
n! h7
 
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public static void log(int sMsg) 4YROB912
 
{ {E_{JB~`  
System.err.println(sMsg); vZAv_8S)  
} DDd/DAkCX  
} VG@};dwbz*  
6[P-Ny{z  
6^F'|Wh  
/*
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**TestMethod.java 1%
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*/ Im72Vt:p-  
package NetFox; ot%.M*h-  
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C"pB"^0  
public class TestMethod { HIc a nk  
J.
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QfpuZEUK  
public TestMethod() Hh[Tw&J4  
{ ///xx/weblogic60b2_win.exe ]!"S+gT*C  
try{ 1T|$BK@)  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); '?5j[:QY@  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); \_]En43mg  
SiteFileFetch fileFetch = new SiteFileFetch(bean); H=c`&N7E  
fileFetch.start(); ;O#g"8  
} cu9Qwm  
catch(Exception e){e.printStackTrace ();} _S?qDG{E|  
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.K8w8X/3  
} 9q[;u
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)r6EW`$  
oy.[+EI`|  
public static void main(String[] args) hUpnI@  
{ g}xQ6rd  
new TestMethod(); _k66Mkd#b  
} s4LO&STh{  
} rxZi8w>}  
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