http断点续传简单实现（java)

/* hX.cdt_?  
**SiteFileFetch.java 1
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*/ 7Qd4L.  
package NetFox; JW D`}  
import java.io.*; C4mkt2Eb0a  
import java.net.*; gP%<<yl  
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public class SiteFileFetch extends Thread { `<YMkp[  
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SiteInfoBean siteInfoBean = null; //文件信息Bean qs]W2{-4~  
long[] nStartPos; //开始位置 E`)e ;^  
long[] nEndPos; //结束位置 )s!A\a`vEd  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,U{dqw8E{  
long nFileLength; //文件长度 +^AdD8U  
boolean bFirst = true; //是否第一次取文件 opfnIkCe  
boolean bStop = false; //停止标志 /TMVPnvz.  
File tmpFile; //文件下载的临时信息 'V&g"Pb  
DataOutputStream output; //输出到文件的输出流 q[U pP`Z%  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） )G2Bx+Z;L  
public SiteFileFetch(SiteInfoBean bean) throws IOException Ne u$SP  
{ -'&l!23a~  
siteInfoBean = bean; XJ7B
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7P
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?NoNg^Of  
if(tmpFile.exists ()) Otq3nBZ  
{ IVxJN(N^  
bFirst = false; -M{szH  
read_nPos(); XRPJPwes]  
} < se~wR  
else mS
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{ qz`-?,pF  
nStartPos = new long[bean.getNSplitter()]; LQF;T7VKS)  
nEndPos = new long[bean.getNSplitter()]; 02]HwsvZ  
} <aPZE6z  
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]9QXQH  
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} C6
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public void run() (#dR\Di  
{ .U{}N%S  
//获得文件长度 EZj rX>"#  
//分割文件 c44s@E  
//实例FileSplitterFetch #66i!}  
//启动FileSplitterFetch线程 Ku'a,\7z  
//等待子线程返回 (cVIjo+::  
try{ }0&Fu?sP  
if(bFirst) gbdzS6XW~  
{ |E6Thvl$  
nFileLength = getFileSize(); Ox)<"8M  
if(nFileLength == -1) %s}{5Qcl/  
{ :a8Sy("  
System.err.println("File Length is not known!"); *$cx7yJ  
} %R5-6  
else if(nFileLength == -2) e/4C` J-  
{ myo4`oH  
System.err.println("File is not access!"); nzbVI  
} BD"Dzq  
else +`flIG3RV  
{ remc_}`w  
for(int i=0;i<nStartPos.length;i++) i6bU
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{ e\}@w1  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Csu9u'.V  
} U/Cc!WXV]  
for(int i=0;i<nEndPos.length-1;i++) dsX"S;`v  
{ Lum=5zDo  
nEndPos = nStartPos[i+1]; 1!zd#TX  
} )7N
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nEndPos[nEndPos.length-1] = nFileLength; VK/L}^=GOO  
} U9B
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} %]F/!n  
6(7 56  
J[}j8x?r  
//启动子线程 +_X*one  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?jmL4V2-f  
for(int i=0;i<nStartPos.length;i++) /\e_B6pF<  
{ p63fpnH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q>+!Ete1p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), NP3 e^  
nStartPos,nEndPos,i); HMD\)vMK6  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E!X>
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fileSplitterFetch.start(); ,./n@.na  
} 2(uh
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y=Eb->a){  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3B]E2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6# bTlmcg  
nEndPos = " + nFileLength); otaRA  
// fileSplitterFetch[nPos.length-1].start(); zZd.U\"2  
a,fcK
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(0@b4}Z  
//等待子线程结束 sw9ri}oc  
//int count = 0; 6lpJ+A57#  
//是否结束while循环 n"?*"Ya  
boolean breakWhile = false; ~|<'@B!6  
a?ete9Q+  
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while(!bStop) C6gp}%  
{ (-J'x%2)  
write_nPos(); aY4v'[  
Utility.sleep(500); X#by Dg  
breakWhile = true; mCn:{G8+  
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~zZOogM<  
for(int i=0;i<nStartPos.length;i++) M]%dFQ  
{ ;[4=?GL*  
if(!fileSplitterFetch.bDownOver) Fsl="RB7f  
{ O=LW[h!  
breakWhile = false; \R9izuc9  
break; [zl4"|_`  
} 'Jek< 5  
} u[SqZftmO  
if(breakWhile) ld"rL6  
break; Ne;0fkO  
8_wh9   
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//count++; AcJrJS)~  
//if(count>4) HS*Y%*  
// siteStop(); r=37Q14v  
} s-IM  
tYgHJ~1L*  
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System.err.println("文件下载结束！"); o; 6^:  
} 4C?4M;  
catch(Exception e){e.printStackTrace ();} oP T)vN?  
} ?x
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//获得文件长度 yIr0D6L  
public long getFileSize() /]0SF_dZ  
{ 2&pE  
int nFileLength = -1; M*cF'go  
try{ FbMtor  
URL url = new URL(siteInfoBean.getSSiteURL()); OVxg9
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0$b4\.0>~  
httpConnection.setRequestProperty("User-Agent","NetFox"); UlNiH  
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int responseCode=httpConnection.getResponseCode(); `gCJ[  
if(responseCode>=400) `t9k!y!GV  
{ g
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processErrorCode(responseCode); a*}>yad  
return -2; //-2 represent access is error 4o";p}[b  
} Cb|1Jtb
 
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4*o?2P$Q  
String sHeader; IMM+g]#e  
G$KQgUN~[  
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for(int i=1;;i++) cL%"AVsj >  
{ j(k%w  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Jqgm>\y  
//Utility.log(in.readLine()); 0;)Q  
sHeader=httpConnection.getHeaderFieldKey(i); - q(a~Ge  
if(sHeader!=null) Yv)c\hm(7j  
{ m6^#pqSL  
if(sHeader.equals("Content-Length")) _OJfd  
{ [n&ES\o#(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2wPc yD  
break; \M|:EG%  
} _iDVd2X"H  
} R i,_x  
else (GGosXU-v  
break; *_J{_7pwe  
} _<F;&(o  
} N^wHO<IO1  
catch(IOException e){e.printStackTrace ();} EbX!;z  
catch(Exception e){e.printStackTrace ();}
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;; {K##^l  
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Utility.log(nFileLength); 8D@
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return nFileLength; L^Q;M,.c;  
} `:EhYj.  
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sSwY!";  
//保存下载信息（文件指针位置） dHg[r|xC  
private void write_nPos() D@.qdRc3  
{ |N)),/R_  
try{ |*b-m k  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Q@PDhISa  
output.writeInt(nStartPos.length); ]xoG{%vgb  
for(int i=0;i<nStartPos.length;i++) |'P$zMAF  
{ 1tI=Dwx  
// output.writeLong(nPos);  .9r85  
output.writeLong(fileSplitterFetch.nStartPos); Ndb7>"
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output.writeLong(fileSplitterFetch.nEndPos); qP&:9eL  
} B/;'D7i|S  
output.close(); %I!2dXNFRF  
} vGPsjxk&  
catch(IOException e){e.printStackTrace ();} #639N9a~  
catch(Exception e){e.printStackTrace ();} dS <*DP  
} }(XKy!G6  
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x H=15JY1W  
//读取保存的下载信息（文件指针位置） +?
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private void read_nPos() YAeF*vP  
{ _/%,cYVc8!  
try{ .oLV\'HAR  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); W[j,QU  
int nCount = input.readInt(); rev*G:  
nStartPos = new long[nCount]; %yjD<2J;  
nEndPos = new long[nCount]; 4 83r
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for(int i=0;i<nStartPos.length;i++) 'DpJ#w\81  
{ q{B?j%.o  
nStartPos = input.readLong(); n|rKo<Y0  
nEndPos = input.readLong(); ~LOE^6C+~o  
} bX:h"6{=R  
input.close(); q3h&
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} dT?3Q;>B?  
catch(IOException e){e.printStackTrace ();}
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catch(Exception e){e.printStackTrace ();} nf
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} kQlwl9  
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private void processErrorCode(int nErrorCode) >nih:5J,ja  
{ H=f|X<8  
System.err.println("Error Code : " + nErrorCode); ]b sabS?  
} mK"s*tD  
to,\n"$~!  
5E~^-
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//停止文件下载 Xxd]j]  
public void siteStop() xh9$ZavB*  
{ >zL5*:G  
bStop = true; m_Q&zp["  
for(int i=0;i<nStartPos.length;i++) ) < U9  
fileSplitterFetch.splitterStop(); c>>.>^5  
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bJD$!*r\%!  
} ysp`(n=  
} NsM`kZM4H  
//负责部分文件的抓取 b l+g7g;  
**FileSplitterFetch.java +`{OOp=  
*/ 5dE=M};v  
package NetFox; + Hv'u  
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import java.io.*; |K-
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import java.net.*; |vGHhzZ|  
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public class FileSplitterFetch extends Thread { E0&d*BI2  
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:|niFK4  
String sURL; //File URL |Rhqi  
long nStartPos; //File Snippet Start Position Q%d1n*;+  
long nEndPos; //File Snippet End Position i 61k  
int nThreadID; //Thread's ID 4:N*C7P  
boolean bDownOver = false; //Downing is over c-Yd> 4+1  
boolean bStop = false; //Stop identical CPRVSN0b{4  
FileAccessI fileAccessI = null; //File Access interface u5g
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h !R=t  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "2sk1  
{ N8#j|yf  
this.sURL = sURL; 51#OlvD  
this.nStartPos = nStart;  +)e|>  
this.nEndPos = nEnd; y;8&J{dd  
nThreadID = id; N1Ag.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6b'.WB]-  
} >,]8iMh  
*tEqu%N1'  
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public void run() {A
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{ DR:$urU$  
while(nStartPos < nEndPos && !bStop) }AJoF41X  
{ hp9U   
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try{
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URL url = new URL(sURL); g""GQeR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); E8}evi  
httpConnection.setRequestProperty("User-Agent","NetFox"); bG@2f"  
String sProperty = "bytes="+nStartPos+"-"; x6s|al  
httpConnection.setRequestProperty("RANGE",sProperty); <]LljTm`i  
Utility.log(sProperty); $Emu*'  
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InputStream input = httpConnection.getInputStream(); RLnL9)`W  
//logResponseHead(httpConnection); !+^'Ej)z  
Y`bTf@EP>  
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byte[] b = new byte[1024]; B<m0YD?>~>  
int nRead; BU/A\4xQ,Y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) V<I(M<Dj  
{ ty0P9.Q  
nStartPos += fileAccessI.write(b,0,nRead); ;t\h"K<,|  
//if(nThreadID == 1) }A24;'}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M]/aW  
} X4!7/&  
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Utility.log("Thread " + nThreadID + " is over!");
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bDownOver = true; ~RuX2u-2&u  
//nPos = fileAccessI.write (b,0,nRead); c!4F0(n4  
} AT~,  
catch(Exception e){e.printStackTrace ();} E3wL n/<  
} M }d:B)cz  
} M[YFyM(
 
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~&73f7  
//打印回应的头信息 "/i$_vl  
public void logResponseHead(HttpURLConnection con) - Fbp!*. u  
{ YoKyiO!   
for(int i=1;;i++) +)jll#}?  
{ _q27 3QG/"  
String header=con.getHeaderFieldKey(i); !EB<N<P"t  
if(header!=null) ob{'Z]-V  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $El-pMq  
Utility.log(header+" : "+con.getHeaderField(header)); 5h#h>0F  
else .w.:o2L  
break; LJ(WU)CPc  
} = (F   
} -o6rY9\_!  
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public void splitterStop() A>yU0\A  
{ l:!L+t*}6  
bStop = true; w!7\wI[  
} Y7VO:o  
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)  
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} MCT1ZZpPr  
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}#O!GG{  
/* oY18a*_>M1  
**FileAccess.java }p7iv:P=3  
*//文件访问(定位，写) }6c>BU}DF  
package NetFox; ijF_ KP'  
import java.io.*; ssi7)0  
MePD:;mm^  
;"wCBuXcu  
public class FileAccessI implements Serializable{ i/ilG3m>  
_6ZjF>f  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 LmF,en5  
RandomAccessFile oSavedFile; \beO5]KS<  
long nPos; C8}:z\A_@Z  
}9'`3vsJ  
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public FileAccessI() throws IOException q!5:M\  
{ %SM;B-/zHt  
this("",0); +J X;T(T  
} g\JJkXjD#  
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public FileAccessI(String sName,long nPos) throws IOException )\fY1WD  
{ $RaN@& Wm  
oSavedFile = new RandomAccessFile(sName,"rw"); pIJXP$v3  
this.nPos = nPos; 4]y)YNQ(  
oSavedFile.seek(nPos); pE
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} '-;[8:y.  
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public synchronized int write(byte[] b,int nStart,int nLen) m|@H`=`d  
{ 9Eyx Ob  
int n = -1; $<^t][{  
try{ W7i|uTM  
oSavedFile.write(b,nStart,nLen); NI >%v  
n = nLen; 4>hHUz[_  
} aLJm%uW6m&  
catch(IOException e) g{65QP  
{ @X2*O9  
e.printStackTrace (); |p11Jt[  
} +2~kHrv  
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return n; ETe4I`d{  
} !_<6
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} A=Wg0eYy\  
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/* `Lf'/q  
**SiteInfoBean.java z$32rt8{`v  
*/ k_al*iM>H  
package NetFox; Hcq.Lq;2:  
'rD6MY  
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public class SiteInfoBean { P3$eomX'  
<B"sp r&1  
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private String sSiteURL; //Site's URL /0h *(nL  
private String sFilePath; //Saved File's Path <j'V}|3  
private String sFileName; //Saved File's Name p\6cpf  
private int nSplitter; //Count of Splited Downloading File aV3:{oL  
vJkc/7  
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public SiteInfoBean() ]b/]^1-(b  
{//nSplitter的缺省值为5 )*,/L <  
//default value of nSplitter is 5 @ D+ft
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this("","","",5); 'Wonz<{'  
} UkV?,P@l  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) (B7G'h.?  
{ s[1ao"sZ^  
sSiteURL= sURL; gg;r;3u  
sFilePath = sPath; E h%61/  
sFileName = sName; pJpapA2l*6  
this.nSplitter = nSpiltter; jcH@*c=%e  
nR!e(  
( ?V`|[+u  
} FqKJids-  
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\INH[X#>  
public String getSSiteURL() )*|/5wW1  
{ 1SQATUV  
return sSiteURL; gt&|T j  
} G1"iu89d  
::L2zVq5V  
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public void setSSiteURL(String value) bQAznd0  
{ i%glQT  
sSiteURL = value; +8=$-E=  
} =lXj%V^8N  
?0tg}0|  
da{]B5p\  
public String getSFilePath() h$>F}n j  
{ !,J# r  
return sFilePath; 73WSW/^F  
} H#-3  
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.b:!qUE^  
public void setSFilePath(String value) $|4C]Me (  
{ l?Y^3x}j  
sFilePath = value; `sxf
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} uFd$*`jS  
'[F:uA  
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public String getSFileName() Z5{a7U4z_  
{ &dtk&P{  
return sFileName; }fpya2Xt  
} fGgt[f[  
;?6vKpj;  
A=CeeC]}  
public void setSFileName(String value) k15vs  
{ )fH Q7  
sFileName = value; r@r%qkh(.@  
} z*Sm5i&)_q  
_MBa&XEM  
`h}eP[jA  
public int getNSplitter() ~Eut_d  
{ ^S#;  
return nSplitter; yTaMlT|  
} -H1=N  
@WJ;T= L  
oL4W>b )  
public void setNSplitter(int nCount) We+rFk1ddt  
{
-F[8ZiZ  
nSplitter = nCount; ^s,3*cAU  
} yr]ja-Y  
} \}-4(Xdaq  
y)f.ON36I  
!`ol&QQ#  
/* 1I Yip\:lS  
**Utility.java _iwG'a[`  
*/ ]{-.?W*$  
package NetFox; p<R:[rz  
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public class Utility { V>$( N/1  
^df wWP  
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public Utility() K/4@2vF  
{ ^5 >e  
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2 a<\4w'  
} w+o5iPLX  
nx9PNl@?V  
//线程睡眠 lED!}h'4  
public static void sleep(int nSecond) M8^ID #  
{ 3CUQQ_  
try{ I-v} DuM  
Thread.sleep(nSecond); 3F9V,zWtTi  
} 6)HmE[[F  
catch(Exception e) P\7DA4]  
{ 5f0M{J,KC  
e.printStackTrace (); ~z[`G#dU  
} /i+z#q5'  
} Q @}$b(b  
0'q4=!l  
//日志 $CcjuPsK  
public static void log(String sMsg) R!VfTAv  
{ :cpj{v;s  
System.err.println(sMsg); $+eeE  
} N
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WR+j?Fcf  
public static void log(int sMsg) !0 7jr%-~  
{ d[9,J?'OQ  
System.err.println(sMsg); s"L&y <?)  
} .Xg.,kW  
} >OG189O  
z%&FLdXgW+  
o$_0Qs$  
/*  /SvhOi  
**TestMethod.java g`EZLDjt  
*/ w0QtGQ|  
package NetFox; rcnH^P  
_K5<)( )  
bC&A@.g{  
public class TestMethod { /"m s  
ET*A0rt  
.[={Yx0!I  
public TestMethod() Po>6I0y
  
{ ///xx/weblogic60b2_win.exe SA,~q&  
try{ t@KTiJI ]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [o^$WL?c
 
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); oRfb4+H&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); h*%p%t<  
fileFetch.start(); :@
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} :J;U~emq
 
catch(Exception e){e.printStackTrace ();} 8)B{x[?|  
Za.}bR6?Y  
[
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} YSjc=  
{R$`YWk  
=dm9+ff  
public static void main(String[] args) =fS
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{ N$=YL @m8  
new TestMethod(); KFM[caKeJO  
} *h^->+0n  
} bLT3:q#s  
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