http断点续传简单实现（java)

/* Cw
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**SiteFileFetch.java
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*/ +LddW0h+=8  
package NetFox; V# Mw  
import java.io.*; lsmzy_gV7  
import java.net.*; fq-$u;~h  
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public class SiteFileFetch extends Thread { <jdS0YT  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "h.}o DS  
long[] nStartPos; //开始位置 |F5^mpU  
long[] nEndPos; //结束位置 W}B4^l
 
FileSplitterFetch[] fileSplitterFetch; //子线程对象 AMqu}G  
long nFileLength; //文件长度 $s2
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boolean bFirst = true; //是否第一次取文件 INwc@XB  
boolean bStop = false; //停止标志 .&2pZ  
File tmpFile; //文件下载的临时信息 8>q:Q<BB2  
DataOutputStream output; //输出到文件的输出流 ?PQiVL  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Q@j:b]Y9  
public SiteFileFetch(SiteInfoBean bean) throws IOException :- 5Mn3*  
{ &a(w0<  
siteInfoBean = bean; /kWWwy<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3&*%>)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1%:A9%O)t  
if(tmpFile.exists ()) .ev]tu2N  
{ ;kFp)*i  
bFirst = false; M1>a,va8Zq  
read_nPos(); E
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} +I~?8*  
else @6Mo_4)O  
{ x-QP+M`Pu  
nStartPos = new long[bean.getNSplitter()]; DxD0iJ=W  
nEndPos = new long[bean.getNSplitter()]; 97g-*K  
} L7b{H22  
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} ;K_B,@:'  
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public void run() %In"Kh*  
{ :({<"H)!'  
//获得文件长度 /6fPC;l  
//分割文件 6]3ZUH;  
//实例FileSplitterFetch =1(BKk>  
//启动FileSplitterFetch线程 `sXx,sV?B  
//等待子线程返回 ?|/}~nj7  
try{ {V&7JZl,/  
if(bFirst) |)_R bqZ  
{ ~_&.A*Jh  
nFileLength = getFileSize(); -$q/7,os  
if(nFileLength == -1) .s?OKy  
{ 5zGj,y>u  
System.err.println("File Length is not known!"); :}z%N7T  
} d7P @_jO6  
else if(nFileLength == -2) Yp)U'8{h c  
{ ?uN(" I  
System.err.println("File is not access!"); {Vm36/a  
} rifxr4c[X>  
else D^{:UbN  
{ YMd&+J`  
for(int i=0;i<nStartPos.length;i++) gK(4<PO'  
{ F~AS(sk  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); .g~@e_;):  
} X A|`wAGP  
for(int i=0;i<nEndPos.length-1;i++) (A
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{ h~@+M5r,  
nEndPos = nStartPos[i+1]; h"ylpv+  
} fz3*oJ'  
nEndPos[nEndPos.length-1] = nFileLength; >C[1@-]G%7  
} 4:']'E  
} ^IH1@  
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}v,THj  
//启动子线程 d@tr]v5 B  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nS4S[|w"  
for(int i=0;i<nStartPos.length;i++) 'qJ-eQ7e  
{ id#k!*$7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D_19sN@0m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), K,C$J I  
nStartPos,nEndPos,i); k.
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ubw!/|mi  
fileSplitterFetch.start(); o~.o^0Y  
} n"<GJ.{  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K@j^gF/0B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); c]aK N  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ;/)Mcx]n  
nEndPos = " + nFileLength); */5<L99v  
// fileSplitterFetch[nPos.length-1].start(); fdq^!MWTi  
6PQJgki  
JX\T {\m#  
//等待子线程结束 10l1a
4  
//int count = 0; QC\g%MVG  
//是否结束while循环 rPo\Dz  
boolean breakWhile = false; {7Gx9(  
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l  
{Z?$Co^R  
while(!bStop) UU;-q_H6  
{ Lr24bv
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write_nPos(); hV>4D&<  
Utility.sleep(500); EYJi6#  
breakWhile = true; A}#]g>L  
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for(int i=0;i<nStartPos.length;i++) ,2 g M-  
{ O
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if(!fileSplitterFetch.bDownOver) M]4=(Vv+5  
{ h[-d1bKwS  
breakWhile = false; 
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break; i>]<*w  
} Av;q:x?  
} P+;CE|J`X  
if(breakWhile) B.Zm$JZ:  
break; veX"CY`hn  
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//count++; 1o;g1Z/  
//if(count>4) n2jvXLJq  
// siteStop(); r{_B:  
} ax72ehL}  
~_l6dDJ  
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System.err.println("文件下载结束！"); y;{^Ln4{  
} c9*1$~(v0I  
catch(Exception e){e.printStackTrace ();} ?x5wS$^q<  
} XoKO2<3  
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//获得文件长度 QX/X {h6  
public long getFileSize() ?u_gXz;A  
{ qLQ <1>u  
int nFileLength = -1; (b/A|hl  
try{ q3AJwELXw  
URL url = new URL(siteInfoBean.getSSiteURL()); ;0w^ud  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fr}1_0DDz  
httpConnection.setRequestProperty("User-Agent","NetFox"); @)W(q5)}9"  
 (kWSK:l  
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int responseCode=httpConnection.getResponseCode(); sJ))<,e5I  
if(responseCode>=400) JQKC;p  
{ ;ZQ-uz  
processErrorCode(responseCode); Awu$g.  
return -2; //-2 represent access is error ;y>S7n>n:  
} \#4m@  
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String sHeader; >5)<Uv$  
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for(int i=1;;i++) yXJ]U \ %  
{ yJ!OsD  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ;B&^yj&;  
//Utility.log(in.readLine()); x(L(l=^"  
sHeader=httpConnection.getHeaderFieldKey(i); Iz DG&c  
if(sHeader!=null) y }\r#"Z`  
{ Og,Y)a;=  
if(sHeader.equals("Content-Length")) KAd_zkUA  
{ >^a$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); t)YUPDQ@J  
break; ` ^DjEdUN  
} "\e:h| .G  
} _ Yfmxn8V  
else 3sH\1)Zz  
break; aF!Ex  
} !; IJ   
} {Fbg]'FQ
 
catch(IOException e){e.printStackTrace ();} =I2
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catch(Exception e){e.printStackTrace ();} P?kx  
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Utility.log(nFileLength); m6^ 5S  
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return nFileLength; >OV<_(S4  
} #ZJMlJ:q`"  
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//保存下载信息（文件指针位置） IV'p~t
 
private void write_nPos() l3.  
{ MaO"#{i  
try{ ;f:gX`"\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); OF[?Z  
output.writeInt(nStartPos.length); 69-:]7.g  
for(int i=0;i<nStartPos.length;i++) 4S|=/f  
{ O gmSQ  
// output.writeLong(nPos); ad9CsvW  
output.writeLong(fileSplitterFetch.nStartPos); j(iuz^I  
output.writeLong(fileSplitterFetch.nEndPos); 4:7mK/Z  
} .[?BlIlm  
output.close(); )tS-.PrA-  
} _T5)n=|  
catch(IOException e){e.printStackTrace ();} &SH1q_&BQ  
catch(Exception e){e.printStackTrace ();} _%~$'Hy  
} rAb&I"\ZY  

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//读取保存的下载信息（文件指针位置） r3qf[?3`6  
private void read_nPos() *FK`&(B+}  
{ y7:tr  
try{ P`S@n/}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); w\Mnu}<e$  
int nCount = input.readInt(); -Fxm
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nStartPos = new long[nCount]; tu0aD%C  
nEndPos = new long[nCount]; N>|XS ,  
for(int i=0;i<nStartPos.length;i++)
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{ n_Onr0EvO  
nStartPos = input.readLong(); WA6!+Gy  
nEndPos = input.readLong(); fuUm}N7  
}
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input.close();
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} QJn`WSw$_-  
catch(IOException e){e.printStackTrace ();} u,1}h L  
catch(Exception e){e.printStackTrace ();} fY,|o3#  
} 3GH(wSv9\  
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private void processErrorCode(int nErrorCode) [q*%U4qGO  
{ jZpa0grA  
System.err.println("Error Code : " + nErrorCode); 9zBMlc$X  
} X[](Kj^`<  
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QAPu<rdJP  
//停止文件下载 g&Vcg`  
public void siteStop() `.%JjsD<  
{ !ABiy6d  
bStop = true; rJJ[X4$  
for(int i=0;i<nStartPos.length;i++) vUA0FoOp  
fileSplitterFetch.splitterStop(); Sv'y e  
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} ]y@F8$D!  
} &fOdlQ?  
//负责部分文件的抓取 e:w&(is  
**FileSplitterFetch.java F_;DN: {  
*/ l[GOs&D1  
package NetFox; jS.g]k  
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import java.io.*; r?/A?DMe  
import java.net.*; TUIk$U?/I  
1f'Hif*r_X  
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public class FileSplitterFetch extends Thread { `J0i.0p  
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String sURL; //File URL }8-\A7T  
long nStartPos; //File Snippet Start Position ZR0r>@M3v<  
long nEndPos; //File Snippet End Position nH|,T%  
int nThreadID; //Thread's ID kS# CEU7  
boolean bDownOver = false; //Downing is over )B# ,  
boolean bStop = false; //Stop identical h#r^teui)  
FileAccessI fileAccessI = null; //File Access interface \2 y5_;O  
kq=V4-a[  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException a:,y Z  
{ ;`YkMS`=W  
this.sURL = sURL; <A5]]{9 +  
this.nStartPos = nStart; !4"^`ors$  
this.nEndPos = nEnd; MPgS!V1  
nThreadID = id; Ycr3HLJy  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {c?JuV4q?  
} lbdTQ6R  
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public void run()  p?D2)(  
{ <*!i$(gn  
while(nStartPos < nEndPos && !bStop) U9y|>P\)T  
{ JA)?p{j  
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try{ ?~"bR%  
URL url = new URL(sURL); GNf482  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); fWc|gq  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;22l"-F  
String sProperty = "bytes="+nStartPos+"-"; CT9   
httpConnection.setRequestProperty("RANGE",sProperty); 6lwta`2  
Utility.log(sProperty); ]uj=:@  
&3F}6W6A  
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InputStream input = httpConnection.getInputStream(); L4u;|-znw  
//logResponseHead(httpConnection); aNn"X y\ k  
/M;#_+VK<  
aI(7nJ=R  
byte[] b = new byte[1024]; NcOPL\  
int nRead; H=
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) im} ?rY  
{ {Gq*e/  
nStartPos += fileAccessI.write(b,0,nRead); <ljI;xE  
//if(nThreadID == 1) s>k Uh  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \Ng\B.IQ  
} *L6PLe  
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L  
Utility.log("Thread " + nThreadID + " is over!"); Q|Y0,1eVp|  
bDownOver = true; Pg9hW  
//nPos = fileAccessI.write (b,0,nRead); d)cOhZy  
} f4-a?bp  
catch(Exception e){e.printStackTrace ();} XC 7?VE  
} TD[EQ  
} YjF|XPv+ l  
^,l_{  
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//打印回应的头信息 ^;,M}|<h  
public void logResponseHead(HttpURLConnection con) a?|vQ*W  
{ *<N3_tx"  
for(int i=1;;i++) }+o:j'jB  
{ MV_Srz  
String header=con.getHeaderFieldKey(i); 0]
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if(header!=null) ETp%s{8  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y@
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Utility.log(header+" : "+con.getHeaderField(header)); j'[m:/  
else ^-FX  
break; aQ^umrj@?9  
} )"f N!9,F  
} 4'$g(+z  
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public void splitterStop() 1O].v&{  
{ 1Je9,dd6  
bStop = true; /bj <Ft\  
} o"wXIHUmV  
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} P%)gO  
5@*'2rO&!  
}:0uo5B7  
/* (feTk72XX  
**FileAccess.java '$4O!YI9@  
*//文件访问(定位，写) e%8|<g+n6  
package NetFox; @ '@:sM_  
import java.io.*; Y(cN}44  
eh1Q7~  
&//wSlL3  
public class FileAccessI implements Serializable{ E_KCNn-f  
iAT)VQ&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8Ll[ fJZA  
RandomAccessFile oSavedFile; LIg{J%  
long nPos; + OV')oE  
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public FileAccessI() throws IOException Oj<S.fi  
{ ["\;kJ.  
this("",0); 0]D0{6x8  
} w9 w%&{j  
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public FileAccessI(String sName,long nPos) throws IOException %|G"-%_E  
{ hOhS)  
oSavedFile = new RandomAccessFile(sName,"rw"); M#|dIbns H  
this.nPos = nPos; V\(:@0"  
oSavedFile.seek(nPos); pP(XIC  
} 8M@
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0%!rx{f#\  
:xKcpY[{  
public synchronized int write(byte[] b,int nStart,int nLen) + [Hh,I7  
{ GUslPnG  
int n = -1; cb5,P~/q  
try{ 2Z20E$Cb
 
oSavedFile.write(b,nStart,nLen); 42>Ge>#F  
n = nLen; Qt]Q:9I[  
} e#/E~r&  
catch(IOException e) .9O$G2'oh  
{ 1-.~7yC  
e.printStackTrace (); 9&RFO$WH  
} 29XL$v],  
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return n; Qr Wj>uR  
} K't]n{$  
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} 5U_H>oD  
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/* |yo\R{&6  
**SiteInfoBean.java V.wqZ {G  
*/ 64:fs?H  
package NetFox; $%VuSrZ&  
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HHqwq.zIy  
public class SiteInfoBean { Gycm,Cy  
dg4vc][  
Vf(6!iRP@  
private String sSiteURL; //Site's URL Wu)>U  
private String sFilePath; //Saved File's Path tH'2
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private String sFileName; //Saved File's Name YJ(*wByM  
private int nSplitter; //Count of Splited Downloading File lsN~*q?~]  
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public SiteInfoBean() u^029sH6j  
{//nSplitter的缺省值为5 BB|?1"neg  
//default value of nSplitter is 5 1>L(ul(qGF  
this("","","",5); 4Vq%N  
} \@&_>us  
:x_'i_w  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }MUn/ [x  
{ r H~" 4  
sSiteURL= sURL; F[
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sFilePath = sPath; NWxUn.Gy9  
sFileName = sName; FZ8b7nJ)4m  
this.nSplitter = nSpiltter; |>z3E z  
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7t
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} G\TfL^A  
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public String getSSiteURL() 8b0d]*q  
{ S;]*)i,v  
return sSiteURL; Pb*5eXk  
} ^U]UqX`  
 ^eoLAL  
} (!EuLL  
public void setSSiteURL(String value) n@G[  
{ "--t e
 
sSiteURL = value; >3&O::]3  
} d|4}obCt  
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4V~?.  
public String getSFilePath() "?mJqA  
{ 2U-3Q]/I}  
return sFilePath; T9s2bC.z55  
} @gG<le6  
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public void setSFilePath(String value) 2<}NB?f`N  
{ |.wEm;Bz  
sFilePath = value; VsA'de!V4[  
} WVLHfkN  
1IVuSp`{FU  
tY <Z'xA?  
public String getSFileName() xCtmXo  
{ E}ZJ)V7  
return sFileName; A2|Ud_  
} )Y)pmjZaG  
xpOg8u5  
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public void setSFileName(String value) ~/*MY  
{ <\;#jF%V  
sFileName = value; o;?/HE%,[  
} 85GKymz$P  
`:axzCrCfR  
hqRw^2
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public int getNSplitter() 6"}?.E$  
{ be +4junf  
return nSplitter; +a*tO@HG  
} \G-KplKS  
&~W:xg(jN  
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public void setNSplitter(int nCount) YQY%M>F@d%  
{ 3$X'Y]5a  
nSplitter = nCount; HbW0wuI  
} QcpXn4/*  
} Xn{1 FJX/  
o^ XtU5SVq  
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/* |DsnNk0c
 
**Utility.java
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*/ sM9+dh  
package NetFox; ^`G}gWBx}w  
l]5w$dded~  
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public class Utility { _8E/)M  
&%-73nYw  
N ,z6y5Lu  
public Utility() >vA2A1WhW  
{ r-<F5<H+K@  
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} )6aAB|  
r9dyA5oD  
//线程睡眠 ow]053:i  
public static void sleep(int nSecond) MNV% =G  
{ Gh}*q|Lz  
try{ ukUGvK  
Thread.sleep(nSecond);
v\{!THCSh  
} ,S!azN=  
catch(Exception e) }+sT4'Ah>  
{ Er{>p|n=  
e.printStackTrace (); GP#aya  
} 8e(\%bX  
} L+q/){Dd(  
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//日志 @/31IOIV]`  
public static void log(String sMsg) gN"7be&J  
{ .p(T^ m2A*  
System.err.println(sMsg); is-7 j7;  
} *I0T{~  
y_?Me]  
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public static void log(int sMsg) {lc\,F*$  
{ hzvd t  
System.err.println(sMsg); `V04\05  
} ^cuc.g)c$?  
} d}4Y(   
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Ll4g[8  
/* 5bgs*.s  
**TestMethod.java wY_)y  
*/ _/tHD]um  
package NetFox; 9c("x%nLpB  
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public class TestMethod { T]c%!&^_  
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'  
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public TestMethod() N=7pK&NHSG  
{ ///xx/weblogic60b2_win.exe k-^mIJo}  
try{ 5f 5f0|ok  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #%h-[/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !/]WrGqbS  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >: g3k  
fileFetch.start(); R)m'lMi|  
} \r+8qC[,  
catch(Exception e){e.printStackTrace ();} BNs@n"k  
Z
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} =D<PVGo9  
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public static void main(String[] args) ]Yn_}Bq  
{ SR|`!  
new TestMethod(); @/ohg0  
} P&^;656r  
} wLnf@&jQ%  
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