http断点续传简单实现（java)

/* h 'F
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**SiteFileFetch.java y,`SLgBID  
*/ +$YluGEJ  
package NetFox; y_=},a  
import java.io.*; 6tBh`nYB=  
import java.net.*; MJ
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public class SiteFileFetch extends Thread { kh'R/Dt  
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SiteInfoBean siteInfoBean = null; //文件信息Bean N>'T"^S/  
long[] nStartPos; //开始位置 d1`us G"  
long[] nEndPos; //结束位置 B-<H8[GkG1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `XJU$c  
long nFileLength; //文件长度 9? #pqw  
boolean bFirst = true; //是否第一次取文件 jo-qP4w  
boolean bStop = false; //停止标志 c-2##Pf_8O  
File tmpFile; //文件下载的临时信息 ft"
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DataOutputStream output; //输出到文件的输出流 ftqi>^i  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） <~[A  
public SiteFileFetch(SiteInfoBean bean) throws IOException Q0}Sju+HX  
{ YMSA[hm  
siteInfoBean = bean; wd/"! A4(  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5GP,J,J  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); h zh%ML3L  
if(tmpFile.exists ()) %:P&!F\?  
{ d4h, +OU
 
bFirst = false; 6uU2+I  
read_nPos(); TzCNY@y  
} m),3J4(q  
else BAq@H8*B  
{ 3+%c*}KC~  
nStartPos = new long[bean.getNSplitter()]; "2}E ARa  
nEndPos = new long[bean.getNSplitter()]; #^>5,
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} dh~+0FZ{A  
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} f/r@9\x  
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public void run() Gj.u
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{ "uz}`G~O
 
//获得文件长度 ZkyH<Aa  
//分割文件 }538vFNi  
//实例FileSplitterFetch 4mG?$kCN  
//启动FileSplitterFetch线程 kc3dWWPe  
//等待子线程返回 PuuO2TZ  
try{ =]OG5b_-Y  
if(bFirst) kO]],Vy`  
{ @y (9LSs  
nFileLength = getFileSize(); 6<h?%j(  
if(nFileLength == -1) v\Y362Xv  
{ 6%K,3R-d  
System.err.println("File Length is not known!"); !;YmLJk;hN  
} PLi[T4u  
else if(nFileLength == -2) nJ.<yrzi  
{ %CxrXU  
System.err.println("File is not access!"); S}=euY'i  
} .H,wdzg)  
else `XwFH#_  
{ %lw!4Z\gg  
for(int i=0;i<nStartPos.length;i++) S z3@h"  
{ FQbF)K~e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +$eEZ;4  
} Yxa
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for(int i=0;i<nEndPos.length-1;i++) xp395ub6  
{ .@Z-<P"  
nEndPos = nStartPos[i+1]; 8?lp:kM  
} UqaLTdYG  
nEndPos[nEndPos.length-1] = nFileLength; %n3l
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} m17H#!`  
} {%S>!RA  
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p&nIUx"  
//启动子线程 g,5r)FU`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 
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for(int i=0;i<nStartPos.length;i++) u0;FQr2  
{  xZ*.@Pkr  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y5}<7s\UDO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), tFvc~zz9  
nStartPos,nEndPos,i); Zhl}X!:c?\  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \\F@_nB,b  
fileSplitterFetch.start(); a'LM6A8~x  
} MYzyg  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N5ityJIgQ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); [dje!5Dc(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", A6APU><dm^  
nEndPos = " + nFileLength); tN'-4<+  
// fileSplitterFetch[nPos.length-1].start(); p/|":(U  
Z|YiYQl[)  
A9_)
}  
//等待子线程结束 j5*W[M9W
 
//int count = 0; ;:JTb2xbb  
//是否结束while循环 v2>.+Eh#  
boolean breakWhile = false; pPUv8, %  
HWFI6N  
87P.K Yy  
while(!bStop) lNcXBtwK@#  
{ 2=3pV!)4}  
write_nPos(); IK%fX/tDyc  
Utility.sleep(500); =?U"#a  
breakWhile = true; QU/Q5k  
D8otUDB{  
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for(int i=0;i<nStartPos.length;i++) WXqrx*?*+  
{ uTNmt]  
if(!fileSplitterFetch.bDownOver) ;?/v}$Pa  
{ Ou~|Q&f'  
breakWhile = false; qB`zyd8yu  
break; VU1;ZJE  
} KGCm@oy  
} }MKm>N  
if(breakWhile) k<xiP@b{y  
break; 4{Vw30DZ  
6e1/h@p\7  
%4:tRF  
//count++; o|\0IG(\  
//if(count>4) ?QGAiu0  
// siteStop(); \de824  
} JzA`*X[  
IfHB+H   
/n= %#{  
System.err.println("文件下载结束！"); iyw"|+  
} (>
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catch(Exception e){e.printStackTrace ();} WH F>J  
} Fg8i} >w  
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^c1%$@H  
//获得文件长度 |k~\E|^  
public long getFileSize() \29a@6  
{ =]h5RC  
int nFileLength = -1; }(AgXvRq  
try{ #un#~s 7Q  
URL url = new URL(siteInfoBean.getSSiteURL()); M6E.!Cs  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @Oe!*|?mS  
httpConnection.setRequestProperty("User-Agent","NetFox"); Py$*c  
5gP#V K  
`nA_WS  
int responseCode=httpConnection.getResponseCode(); U88-K1G  
if(responseCode>=400) YYDLFtr2  
{ m2[q*k]AtS  
processErrorCode(responseCode); v~>^c1:  
return -2; //-2 represent access is error =F2e*?a3  
} FL5u68  
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String sHeader; sidSY8j  
ar
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for(int i=1;;i++) Fx']kn9  
{ ^E&':6(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); FHVZ/ e  
//Utility.log(in.readLine()); @,i_ KN6C  
sHeader=httpConnection.getHeaderFieldKey(i); o/EA%q1  
if(sHeader!=null) 8UArl
3  
{ ,5" vzGLJ  
if(sHeader.equals("Content-Length")) =:rR%L!a  
{ /[YH W]  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1<_i7.{k  
break; 7_ g}t!b`  
} p:u?a,p  
}
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else "=I ioY  
break; "J(#|v0  
} 1_uq46  
} 'ypJGm  
catch(IOException e){e.printStackTrace ();} !n4p*<Y6  
catch(Exception e){e.printStackTrace ();} dxlaoyv:  
BgLK}p^  
cCN[c)[c|  
Utility.log(nFileLength); z5Hz-.  
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return nFileLength; O.S(H1z<G  
} j;eR9jI$T  
SEQ bw](ss  
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//保存下载信息（文件指针位置） /)?]
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private void write_nPos() )|f!}( p  
{ dV#h~  
try{ eS9/-Y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S5]rIcM  
output.writeInt(nStartPos.length); s<x2*yVUA  
for(int i=0;i<nStartPos.length;i++) ?}y?e}y*xZ  
{ uNV(r"
 
// output.writeLong(nPos); pulE6T7x  
output.writeLong(fileSplitterFetch.nStartPos); CZg$I&x  
output.writeLong(fileSplitterFetch.nEndPos); h0`@yo  
} uZ*;
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output.close(); Ro`Hm8o/  
} nb0V~W  
catch(IOException e){e.printStackTrace ();} qCOe,$\1/  
catch(Exception e){e.printStackTrace ();} G@b|{!  
} bWAhK@epI  
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//读取保存的下载信息（文件指针位置） -xtj:UO  
private void read_nPos() Hw[u Sv8  
{
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try{ 8)3g!3S  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g83]/s+  
int nCount = input.readInt(); x7 jE Ns )  
nStartPos = new long[nCount]; e"P>b? OY  
nEndPos = new long[nCount]; :
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for(int i=0;i<nStartPos.length;i++) ^yiRrcOo  
{ W>036  
nStartPos = input.readLong(); c*ac9Y'o  
nEndPos = input.readLong(); G (Fi  
} %c)^8k;I  
input.close(); k_.%(ZE  
} GMRw+z4  
catch(IOException e){e.printStackTrace ();} k8w }2Vw  
catch(Exception e){e.printStackTrace ();} !]7r>NS>  
} '"Q;54S**  
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private void processErrorCode(int nErrorCode) 
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{ jI!}}K)d  
System.err.println("Error Code : " + nErrorCode); W#E-vi+l  
} -4{sr| lm  
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//停止文件下载 7*]O]6rP  
public void siteStop() ;muxIr`?  
{ ,Hn{nVU1R=  
bStop = true; 5O<7<OB  
for(int i=0;i<nStartPos.length;i++) }6MHIr=o  
fileSplitterFetch.splitterStop(); j-@3jFu  
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} EE5I~k5  
} GV'Y'  
//负责部分文件的抓取 I|]~f[xI  
**FileSplitterFetch.java 'v iF8?_  
*/ XhjH68S(  
package NetFox; ~#+ Hhc(  
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import java.io.*; fF37P8Ir  
import java.net.*; AdDlS~\?  
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public class FileSplitterFetch extends Thread { jFfuT9oId  
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String sURL; //File URL yUcWX bT@  
long nStartPos; //File Snippet Start Position /pni_-l*  
long nEndPos; //File Snippet End Position `MtI>x c  
int nThreadID; //Thread's ID *^+8_%;1  
boolean bDownOver = false; //Downing is over F3j#NCuO=z  
boolean bStop = false; //Stop identical |9cJO@  
FileAccessI fileAccessI = null; //File Access interface }_m/3*x_  
]Gm"U!h*  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ikd~k>F  
{ Oo<L~7B  
this.sURL = sURL; 7kJ =C  
this.nStartPos = nStart; luAmq+  
this.nEndPos = nEnd; V*HkFT  
nThreadID = id; w4w[q
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fileAccessI = new FileAccessI(sName,nStartPos);//定位 GqB]^snh  
} R+Q..9P  
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public void run() ~kM# lh7At  
{ J_) .Hd  
while(nStartPos < nEndPos && !bStop) d2f   
{ Bbk=0+ ^8I  
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C{
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try{ _qwKFC  
URL url = new URL(sURL); X}Heaqn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /, T@/  
httpConnection.setRequestProperty("User-Agent","NetFox"); uR#aO''  
String sProperty = "bytes="+nStartPos+"-"; @}sxA9a  
httpConnection.setRequestProperty("RANGE",sProperty); eiE36+'>b  
Utility.log(sProperty); zi M~V'  
0~2~^A#]\  
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InputStream input = httpConnection.getInputStream(); t;g=@o9YA  
//logResponseHead(httpConnection); <49Gsm&0  
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byte[] b = new byte[1024]; hfzmv~*  
int nRead; |Et8FR3[m  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \/E+nn\)  
{ M'gw-^(  
nStartPos += fileAccessI.write(b,0,nRead); A#/O~-O^  
//if(nThreadID == 1) );-?~   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AG?cI@',  
} S+aXlb  
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4O}ZnE1[  
Utility.log("Thread " + nThreadID + " is over!"); t.0F  
bDownOver = true; ^lADq']  
//nPos = fileAccessI.write (b,0,nRead); xz5V.  
} XNODDH  
catch(Exception e){e.printStackTrace ();} `
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} dV_ClH &)  
} EC
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Vu6$84>-,  
//打印回应的头信息 Y|%s =0M  
public void logResponseHead(HttpURLConnection con) F\LAw#IJ  
{ =QG@{?JTl  
for(int i=1;;i++) QnHb*4<  
{ ry^FJyjW  
String header=con.getHeaderFieldKey(i); "9Q @&C  
if(header!=null) OUoN  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y;oPg4  
Utility.log(header+" : "+con.getHeaderField(header)); :zN{>,sC  
else XEK%\o}  
break; of?hP1kl[  
} K9\p=H^T7  
} }.+{M.[}  
$Sz@u"ig%  
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public void splitterStop() YVSAYv_ZG}  
{ ~< ~PaP$=\  
bStop = true; -|Z[GN:  
} #j!RbW  
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nd~cpHQR^  
} LmCr[9/  
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/* !'yCB9]O  
**FileAccess.java VTM*=5|c  
*//文件访问(定位，写) /=o~7y  
package NetFox; }q8|t3  
import java.io.*; G)<NzZo  
x?5D>M/Y  
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e  
public class FileAccessI implements Serializable{ D7v-+jypp  
}bkQr)us  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Vp"=8p#k  
RandomAccessFile oSavedFile; \L6kCY  
long nPos; "e)C.#3  

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public FileAccessI() throws IOException o p{DPUO0  
{ No
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this("",0); |DB7o+4  
} i
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*/8b)I}yY  
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public FileAccessI(String sName,long nPos) throws IOException Ev%_8CO4e  
{ k4@$vxy0  
oSavedFile = new RandomAccessFile(sName,"rw"); yaDK_fk  
this.nPos = nPos; kK62yz,  
oSavedFile.seek(nPos); <in#_Of{E  
} G0e]PMeFl  
06)B<
 
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public synchronized int write(byte[] b,int nStart,int nLen) 1$+-?:i C  
{ CP5vo-/)-  
int n = -1; x-hr64WFK  
try{ QYS 1.k  
oSavedFile.write(b,nStart,nLen); zc1y)s0G  
n = nLen; Y.7iKMp(  
} qwf97pg$  
catch(IOException e) PM(M c]6  
{ AbqeZn  
e.printStackTrace (); pgp@Zw)r)k  
} %1\MW+  
"W"
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return n; F\K&$
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} t@_MWF  
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?.*^#>
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} 84X/=l-c=  
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Xc>M_%+R  
/* VuU{7:  
**SiteInfoBean.java %I`%N2ss  
*/ ?QbxC,& i  
package NetFox; 0Z11V9Jk  
@N(*1,s2  
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public class SiteInfoBean { cN?}s0  
T
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 ay  
private String sSiteURL; //Site's URL t_Q\uo}  
private String sFilePath; //Saved File's Path ~_XK<}SK  
private String sFileName; //Saved File's Name h?D>Dfeg%  
private int nSplitter; //Count of Splited Downloading File $vC}Fq  
&/\Q6$a  
l-mt{2  
public SiteInfoBean() 1
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{//nSplitter的缺省值为5 )XFaVkQ}  
//default value of nSplitter is 5 I1Jhvyd?$  
this("","","",5); 6Fe$'TP  
} `!um)4  
i 6DcLE  
nt
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ru>c\X^|  
{ #Yd'Vve  
sSiteURL= sURL; bJWPr  
sFilePath = sPath; L-,C5^  
sFileName = sName; uOv0ut\\G  
this.nSplitter = nSpiltter; :(?F(Q^  
Y!1x,"O'H  
=Z(_lLNmh  
} H1
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DI)!x {"  
public String getSSiteURL() X<8   
{ O8mmS!  
return sSiteURL; O]1aez[  
} -Uj3?W  
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1SwKd*aRR?  
public void setSSiteURL(String value) phc9esz  
{ JNx;/6'd,  
sSiteURL = value; 3~ptD5@WF  
} nf2[hx@=U  
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public String getSFilePath() m\DI6O"u'  
{ \Ctl(uj  
return sFilePath; UXdnN;0  
} F, 39'<N[  
-ld1o+'`v!  
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public void setSFilePath(String value) #Aver]e
K  
{ H[e=^JuD  
sFilePath = value; `^G?+p2E  
} >OotgJnhC  
{Y6;/".DM  
nX>HR
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public String getSFileName() u]$e@Vw.  
{ !\hUjM+(}  
return sFileName; vFx0B?  
} 0)0,&@])7  
I%b}qC"5M  
6E))4 lW  
public void setSFileName(String value) D\LXjEme.  
{ P:QSr8K  
sFileName = value; <?E~Qc t  
} Oe_*(q&  
`%<^$Ng
;  
~6!TMVr  
public int getNSplitter() 5f-eWW]!  
{ tXg>R _\C  
return nSplitter; L Rn)  
} mNDd>4%H_  
CYHo~VIK  
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public void setNSplitter(int nCount) y yqya[-11  
{ Kd|@  
nSplitter = nCount; >J['so2Bf  
} s+@`Z*B5  
} &~&nJr  
av:9kPKm  
`;v5o4.`  
/* T@?uA*J  
**Utility.java XR@C^d  
*/ W
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package NetFox; 1c19$KHu  
abw7{%2  
L^%jR=  
public class Utility { LO@='}D=  
,5Nf9z!hk(  
P7|x=Ew;`  
public Utility() b!gvvg<  
{ g7g^iLU  
-8%[7Z]  
a`E1rK'  
} =&-+{txs  
iRsK;)<  
//线程睡眠 '^ob3N/Y [  
public static void sleep(int nSecond) xL#UMvZ>;h  
{ +/|t8zFWs  
try{ V'm4DR#M  
Thread.sleep(nSecond);  }0f"SWO>  
} svj0;x5  
catch(Exception e) u~7 ,v  
{ ~Kll.  
e.printStackTrace (); )|Md"r_B  
} d>k"#|  
} >oasA2S  
t{g7 :A  
//日志 >21f
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public static void log(String sMsg) n~C!PXE  
{ 3{FUFx  
System.err.println(sMsg); En:/{~9{F  
} |9x H9@^f  
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0hoi=W6AQ  
public static void log(int sMsg) q-5U,!!W/  
{ E,$5V^ 9  
System.err.println(sMsg); +S C;@'  
} $`'Xb  
}  Y!*F-v@  
k:sFI @g  
U_l#lGA(H  
/* *-lw2M9V  
**TestMethod.java "&{sE RYY  
*/ am(jmf::  
package NetFox; ]<g`rR
7}  
vC|V8ea  
us$=)m~v+  
public class TestMethod { 's7 (^1hH  
{6Qd,CX
 
! 1wf/C;=  
public TestMethod() I]vCra  
{ ///xx/weblogic60b2_win.exe (n
{,R  
try{ hY[Vs5v  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L.R4 iN  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Bq*aP*jv  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #}|g8gh  
fileFetch.start(); V0/O T~gS8  
} qdY*y&}"J  
catch(Exception e){e.printStackTrace ();} na-mh E,H  
%wk3&EC.  
MFqM6_  
} /KLs+^c5  
9n!IdqKN  
}n[<$*W^  
public static void main(String[] args) k%2Rv4)hU  
{ 2GW.'\D  
new TestMethod(); OHyB
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} ^!yJ;'H\  
} } Rs@  
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