http断点续传简单实现（java)

/* ~-#Jcw$+n=  
**SiteFileFetch.java %DM0Z8P$B-  
*/ Z9eP(ip  
package NetFox; 1Cw HGO  
import java.io.*; xqfIm%9i}  
import java.net.*; A2SD
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public class SiteFileFetch extends Thread { :QC |N@C  
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SiteInfoBean siteInfoBean = null; //文件信息Bean w-3Lw<  
long[] nStartPos; //开始位置 &Tg~A9y\  
long[] nEndPos; //结束位置 AWi+xo|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Kl<NAv%j  
long nFileLength; //文件长度 )KOIf{  
boolean bFirst = true; //是否第一次取文件 }i J$&CJ  
boolean bStop = false; //停止标志 tVh"C%Vkr  
File tmpFile; //文件下载的临时信息 ] !n3j=*  
DataOutputStream output; //输出到文件的输出流 AcHeZb8b  
vU$n*M1`$  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） A9MTAm{  
public SiteFileFetch(SiteInfoBean bean) throws IOException :*s@L2D6  
{ D 9UM8Hxi  
siteInfoBean = bean; k 7:Z\RGy  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); U+zntB  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); V[n,fEPBr  
if(tmpFile.exists ()) J$lfI^^  
{ %M:$ML6b<  
bFirst = false; fk!9` p'  
read_nPos(); sG\K$GP!  
} ]E6r)C  
else x"r,l/gzy  
{ =}YX I  
nStartPos = new long[bean.getNSplitter()]; !j}L-1*{ l  
nEndPos = new long[bean.getNSplitter()]; j4u ["O3  
} | ^G38  
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CE  
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} ?!O4ia3nFk  
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public void run() F@mxd  
{ Wg20H23XW  
//获得文件长度 '.C#"nY>1  
//分割文件 UuC-R)  
//实例FileSplitterFetch VfUHqdg-  
//启动FileSplitterFetch线程 $Ggnn#  
//等待子线程返回 3W{!\  
try{ nLx|$=W  
if(bFirst) 6OoOkN
WF  
{ 6b9J3~d\E  
nFileLength = getFileSize(); a$Hq<~46  
if(nFileLength == -1) ~+ 9vz  
{ *eX/ZCn  
System.err.println("File Length is not known!"); M&)\PbMc  
} 7D1$cmtH  
else if(nFileLength == -2) IR#BSfBZ  
{ c=zSq%e   
System.err.println("File is not access!"); !qU
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} N9*:]a  
else U`5/tNx  
{ \>G}DGz  
for(int i=0;i<nStartPos.length;i++) m)3M)8t  
{ /0$fYrg>J  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (=%0$(S>  
} <fF|A
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for(int i=0;i<nEndPos.length-1;i++) noM=8C&U  
{ 1vxQ`)a  
nEndPos = nStartPos[i+1]; Gp+\}<^Z  
} '.M4yif\g  
nEndPos[nEndPos.length-1] = nFileLength; `oH4"9&]k3  
} (w:,iw#  
} P$Oj3HD LM  
-e_op'`  
Js vdC]+  
//启动子线程 `( w"{8laB  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; _ Yc"{d3S  
for(int i=0;i<nStartPos.length;i++) j9l32<h7]  
{ *ra>Kl0   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vbd)L$$20+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /'5d0' ,M  
nStartPos,nEndPos,i); ch25A<O<R.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); P|Gwt&  
fileSplitterFetch.start(); &GkD5
b  
} 4 Y
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LAH">E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); SOn)'!g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ie|5,qw E  
nEndPos = " + nFileLength); d4*SfzB  
// fileSplitterFetch[nPos.length-1].start(); ' QMcQvU  
kkWv#,qwU  
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//等待子线程结束 &1R#!|h1W  
//int count = 0; &pjj
 
//是否结束while循环 H7z)OaM  
boolean breakWhile = false; C*3St`2@9  
J7^UQ  
$;'M8L  
while(!bStop) =J)<Nx.gA  
{ wDGb h=  
write_nPos(); GZ,MC?W  
Utility.sleep(500); =QGmJ3  
breakWhile = true; x^EW'-a  
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for(int i=0;i<nStartPos.length;i++) ;+(VO  
{ q6w)zTpJGJ  
if(!fileSplitterFetch.bDownOver) ~J&-~<%P}  
{ E #B$.K  
breakWhile = false; J-<_e??  
break; /I!62?)-*  
} 6/5,n0  
} ,[zSz8R  
if(breakWhile) ;Q^>F6+_m  
break; BxjSo^n  
(RV#piM  
>}%#s`3W1_  
//count++;
AvB=/p@]  
//if(count>4) IZ7o6Etti  
// siteStop(); ES AX}uF  
} 2xflRks  
..X_nF  
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System.err.println("文件下载结束！"); Yj/o17  
} ",D!8>=s  
catch(Exception e){e.printStackTrace ();} DXI4DM"15I  
} 8FMxn{k2  
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jH
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//获得文件长度 KFwuz()7  
public long getFileSize() 6p*X8j3pW  
{ rDhQ3iCqo  
int nFileLength = -1; c:u*-lYmK%  
try{ eZqEFMBTm  
URL url = new URL(siteInfoBean.getSSiteURL()); ZY]$MZf5yo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^4+NPk  
httpConnection.setRequestProperty("User-Agent","NetFox"); E+qLj|IU  
lZL+j
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int responseCode=httpConnection.getResponseCode(); J8p;1-C"  
if(responseCode>=400) 5WJ ~%"O  
{ ndzADVP  
processErrorCode(responseCode); a1y<Y`SC9  
return -2; //-2 represent access is error Um{) ?1  
} 3qf#NJN}  
I9qFXvqL  
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String sHeader; 3*~`z9-z  
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for(int i=1;;i++) uX3yq<lK"  
{ ?'+]d;UO&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); cZ|*Zpk  
//Utility.log(in.readLine()); RQ=$, i`  
sHeader=httpConnection.getHeaderFieldKey(i); zKGZg>q  
if(sHeader!=null) yuBRYy#E|%  
{ F:T(-,  
if(sHeader.equals("Content-Length")) } &+]UGv  
{ V 97ORI  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Mf#@8"l  
break; [*p;+&+/ZM  
} 2A;i  
} %%}l[W  
else AXHY
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break; rHB>jN@$  
} #o/;du  
} .1RQ}Ro,<  
catch(IOException e){e.printStackTrace ();} hdx_Tduue  
catch(Exception e){e.printStackTrace ();} 9 da=q  
(WC =om  
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Utility.log(nFileLength); tj~r>SRb+  
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~6n|GxR.[  
return nFileLength; PiM(QR  
} 5?SE?VC=t  
2|lR@L sr  
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//保存下载信息（文件指针位置） v4s4D1}  
private void write_nPos() bWp:!w#K  
{ W,6q1  
try{ iv_3R}IbX  
output = new DataOutputStream(new FileOutputStream(tmpFile)); "h_f-vP  
output.writeInt(nStartPos.length); f&4+-w.:V|  
for(int i=0;i<nStartPos.length;i++) y EfAa6  
{ s(3u\#P  
// output.writeLong(nPos); m_oUl(pk  
output.writeLong(fileSplitterFetch.nStartPos); _Sfu8k>):  
output.writeLong(fileSplitterFetch.nEndPos); ~6kF`}5  
} n'^`;-  
output.close(); |.$B,cEd  
} F$tzsz,9n  
catch(IOException e){e.printStackTrace ();} yKl^-%Uq<  
catch(Exception e){e.printStackTrace ();} H!]&
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} -%M
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/B?wn=][  
//读取保存的下载信息（文件指针位置） kE'p=dXx  
private void read_nPos() 8QJr!#u  
{ jFdgFKc)  
try{ OP=brLGu0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); en'[_43  
int nCount = input.readInt(); HJN GO[*g  
nStartPos = new long[nCount]; 1?H; c5?d&  
nEndPos = new long[nCount]; gU+yqT7=  
for(int i=0;i<nStartPos.length;i++) w/o^OjwQ  
{ |
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nStartPos = input.readLong(); Y+Z+Y)K
  
nEndPos = input.readLong(); tqh)yr;  
} ,\"x#Cc f  
input.close(); V[kJ;YLPN  
} 1/?Wa  
catch(IOException e){e.printStackTrace ();} vc|tp_M67  
catch(Exception e){e.printStackTrace ();} W vB]Rs  
} g]L8Jli  
}C_g;7*  
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private void processErrorCode(int nErrorCode) 1
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{ J' P:SC1  
System.err.println("Error Code : " + nErrorCode); k 6[   
} e
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\A\  
//停止文件下载  ,c`6-  
public void siteStop() {z_cczJ-  
{ yJC: bD1xi  
bStop = true; /c=8$y\%@  
for(int i=0;i<nStartPos.length;i++) s3JzYDpy  
fileSplitterFetch.splitterStop(); !`=iKe&%E  
A'jL+dI.  
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} cI8\d 4/py  
} ;~:Z~8+{c  
//负责部分文件的抓取 + >dC  
**FileSplitterFetch.java -{OJM|W+  
*/ ,0h{RZKw  
package NetFox; qbq2Bi'a  
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{  
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import java.io.*; P{K\}+9F   
import java.net.*; 5,MM`:{{  
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:!Q(v(
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public class FileSplitterFetch extends Thread { JJ)  
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String sURL; //File URL W895@  
long nStartPos; //File Snippet Start Position e"^WXP.t&  
long nEndPos; //File Snippet End Position /'DAB**  
int nThreadID; //Thread's ID +sn0bi/rG  
boolean bDownOver = false; //Downing is over v2]N5  
boolean bStop = false; //Stop identical ?SYmsaSr5  
FileAccessI fileAccessI = null; //File Access interface ;U?=YSHk7  
W#g!Usf:/  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException -!~pa^j  
{ WP\kg\o  
this.sURL = sURL; ]#shuZ##>0  
this.nStartPos = nStart; \kyoA Z  
this.nEndPos = nEnd; 2<J2#}+\  
nThreadID = id; $bMmyDw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P|ibUxSA~,  
} J3aom,$o  
}KUK|p5  
/V+7:WDj  
public void run() k}g4?  
{ GL0P&$h  
while(nStartPos < nEndPos && !bStop) aOinD  
{ r\fkx>  
$ZyOBxI  
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try{ XLiwE$:t%  
URL url = new URL(sURL); ~5|R`%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l=P)$O|=w  
httpConnection.setRequestProperty("User-Agent","NetFox"); VSUWX1k4%  
String sProperty = "bytes="+nStartPos+"-"; gA
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httpConnection.setRequestProperty("RANGE",sProperty); w$&;s<0  
Utility.log(sProperty); .u&X:jO
E  
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InputStream input = httpConnection.getInputStream(); bydI+pVMo  
//logResponseHead(httpConnection); PyI"B96gz  
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byte[] b = new byte[1024]; s^PsA9EAn  
int nRead; 9UteD@*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <6.`(isph  
{ X^&--@l}T!  
nStartPos += fileAccessI.write(b,0,nRead); R>Ox(MG  
//if(nThreadID == 1) um/F:rp  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6:QlHuy0nH  
} t; #@t/`  
-8"
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Utility.log("Thread " + nThreadID + " is over!"); *=O3kUoL  
bDownOver = true; UnVa`@P^:G  
//nPos = fileAccessI.write (b,0,nRead); ib> ~3s;  
} TT;ls<(Lg  
catch(Exception e){e.printStackTrace ();} 9k9}57m.i  
} p {.6  
} fbdpDVmpU  
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//打印回应的头信息 @>ys,dy  
public void logResponseHead(HttpURLConnection con) k&[6Ld0~56  
{ W"\`UzOLQ  
for(int i=1;;i++)
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{ 5sEk rT '  
String header=con.getHeaderFieldKey(i); ep5`&g]3  
if(header!=null) ^(T~Qp  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [q0^Bn}h  
Utility.log(header+" : "+con.getHeaderField(header)); ,bM):  
else <h+UC# .x  
break; FD%OG6db];  
} 'bH~KK5  
} 7$0bgWi  
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public void splitterStop() !w/fwOo  
{ VS`
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bStop = true; OqH3.@eK  
} 58mpW`Q  
Z"Q9^;0%  

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} 8qfXc ^6  
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/* =%I;
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**FileAccess.java mss.\  
*//文件访问(定位，写) S&l [z,  
package NetFox; %<O~eXY  
import java.io.*; O\=Zo9(NHF  
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P%R9\iajH  
public class FileAccessI implements Serializable{ ;ioF'ov  
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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 fpO2bD%$8  
RandomAccessFile oSavedFile; +_*iF5\  
long nPos; M
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public FileAccessI() throws IOException \v{HjqVkC  
{ QAl4w)F  
this("",0); 6N Ogi  
} bQN3\mvY  
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public FileAccessI(String sName,long nPos) throws IOException F_/ra?WVH  
{ 9@Cu5U]  
oSavedFile = new RandomAccessFile(sName,"rw"); eQ[}ALIq  
this.nPos = nPos; +4qR5
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oSavedFile.seek(nPos); >lJTS t5{  
} eqOT@~H  
TB<$9FCHK  
{7$jwk  
public synchronized int write(byte[] b,int nStart,int nLen) |,H2ge  
{ @a=jSB#B  
int n = -1; qrZ3`@C4k  
try{ d|W=_7z  
oSavedFile.write(b,nStart,nLen); ,E%O_:}R  
n = nLen; {C8IYBm  
} pP"j|  
catch(IOException e) ?y"M>#  
{ `q |
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e.printStackTrace (); hc9ON&L\>  
} jWvi%Iqi  
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return n; ?V~vP%1  
} +RiI5.$=Z  
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} 7dE.\#6r  
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/* J5<16}*  
**SiteInfoBean.java KCp9P2kv.  
*/ '9Q#%
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package NetFox; +T,A^(&t  
b53s@7/mq  
:}#j-ZCC"  
public class SiteInfoBean { xDS]k]/(T  
Z@*!0~NH=4  
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private String sSiteURL; //Site's URL *p\fb7Pu_3  
private String sFilePath; //Saved File's Path !4Sd^"  
private String sFileName; //Saved File's Name zITxJx  
private int nSplitter; //Count of Splited Downloading File /Ah'KN|EN  
%z.d;[Hs  
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public SiteInfoBean() /+ais3  
{//nSplitter的缺省值为5 JFNjc:4{0  
//default value of nSplitter is 5 !HhF*Rlr  
this("","","",5); s%~Nx3,  
} 0~[M[T\  
'V <ZmJ2  
~*^o[~x]\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) c@nh>G:y{&  
{ %uiCC>cC  
sSiteURL= sURL; ,R7j9#D  
sFilePath = sPath; Fo~q35uB  
sFileName = sName; $S2 /*  
this.nSplitter = nSpiltter; tWaGCxaE  
@`^Z5n.4  
*mYGs )|  
} -Edi"B4K  
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[ `_sH\  
public String getSSiteURL() w?M"`O(  
{ &5B/>ag1!  
return sSiteURL; Are0Nj&?
 
} \CS4aIp  
j+gh*\:q  
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public void setSSiteURL(String value) C}L2'l,  
{ O9ro{ k  
sSiteURL = value; z 9WeOs  
} h\~!!F  
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&wu1Zz[qcz  
public String getSFilePath() nhZ/^`Y<  
{ ;/IXw>O(/  
return sFilePath; #8BI`.t)j  
} hew"p(`  
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VOg'_#I  
public void setSFilePath(String value) ^![7X'!;pt  
{ zh(=kS`  
sFilePath = value; !#e+!h@  
} I,]q;lEMt  
N\?__WlBK7  
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public String getSFileName() ;DKJ#tS}"  
{ -0NkAQrg  
return sFileName; [I<J6=  
} wCj)@3F  
hwi_=-SL  
pm[i#V<v  
public void setSFileName(String value) Uw3wR!:  
{ /pLf?m9  
sFileName = value; oBo |eRIt|  
} x7jFYC  
%ca`v;].  
6J$I8b#/  
public int getNSplitter()
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{ Y%r>=Jvu6  
return nSplitter; Bcb '4*:  
} M}=>~TA@  
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P1$D[aF9$  
public void setNSplitter(int nCount) Wk!<P" nHd  
{ |fgh ryI,  
nSplitter = nCount; WU,b<PU &  
} =&FaMR2  
} OcC|7s",  
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/* zzd PR}VG  
**Utility.java 6C ?,V3Z  
*/ z('t#J!b  
package NetFox; E!L_"GW  
]4K4Nh~  
1v
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public class Utility { Z=a~0&G  
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_C|j"f/}  
public Utility() Kt/:caD  
{ 4<f^/!9w  
b+$wx~PLi  
4.~<|T8  
} la^K|!|  
# 00?]6`z  
//线程睡眠 Pw6%,?lQ  
public static void sleep(int nSecond) j}fSz)`i  
{ Ies` !W^  
try{ OO,EUOh-T:  
Thread.sleep(nSecond); 15Jc PDV  
} J'k^(ZZ  
catch(Exception e) \i<7Lk  
{ \+x#aN\  
e.printStackTrace (); = U[$i"+  
} 2NB$(4/  
} ]a[2QQ+g  
]M~7L[  
//日志 ]x%sX|Rj  
public static void log(String sMsg) )a%E $`  
{ /neY2D6  
System.err.println(sMsg); kX)*:~*  
} `v'yGsIV  
W[>qiYf^b  
7=&+0@R#/d  
public static void log(int sMsg) B^{~,'  
{ dh%
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System.err.println(sMsg); _G2)=yj]  
} +HgyM0LFg  
} 2~vvE  
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.*z$vl  
/* t oM+Bd:Y  
**TestMethod.java EZT 8^m  
*/ BaMF5f+  
package NetFox; - Nt8'-  
+G,_|C2J
 
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public class TestMethod { F'JT7#eX  
#5iwDAw:|r  
bkrl>Im<n  
public TestMethod() B$7Cjv  
{ ///xx/weblogic60b2_win.exe 5'<a,,RKu  
try{ pOj8-rr  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); y'z9Ya  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); kL<HGQt  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?30pNF|  
fileFetch.start(); c6iFha;db  
} -"XHN=H  
catch(Exception e){e.printStackTrace ();} #/\Zo &V8  
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} (nYGN$qC9  
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$+,kibk*R  
public static void main(String[] args) )r(e\_n  
{ 6t'.4SR  
new TestMethod(); 3~LNz8Z*  
} |`+ (O  
} ^Of\l:q*  
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