http断点续传简单实现（java)

/* kfb/n)b'  
**SiteFileFetch.java w?vVVA  
*/ 5MTgK=c  
package NetFox; Lm*VN~2  
import java.io.*; CJknJn3m&  
import java.net.*; I+ l%Sn#\  
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public class SiteFileFetch extends Thread { 9<Eg}Ic  
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SiteInfoBean siteInfoBean = null; //文件信息Bean jn%kG ~]'Q  
long[] nStartPos; //开始位置 k_|^kdWJ  
long[] nEndPos; //结束位置 -cF'2Sfr  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 zoDZZ%{  
long nFileLength; //文件长度 [U =Uo*  
boolean bFirst = true; //是否第一次取文件 l.)}t)my}  
boolean bStop = false; //停止标志 SkNre$>t{  
File tmpFile; //文件下载的临时信息 j=+"Qz/hr_  
DataOutputStream output; //输出到文件的输出流 ^H'a4G3  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^4Am %yyT  
public SiteFileFetch(SiteInfoBean bean) throws IOException G* b2,9&F  
{ yBed kj  
siteInfoBean = bean; we7c`1E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;;s* Ohh  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ,8G{]X)  
if(tmpFile.exists ()) Y(
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{ NmIHYN3  
bFirst = false; B6P|Z%E;D6  
read_nPos(); V}w;Y?]J  
} gYop--\14]  
else ybdd;t}&1  
{ xG&SX#[2  
nStartPos = new long[bean.getNSplitter()]; t%1^Li  
nEndPos = new long[bean.getNSplitter()]; O;Y:uHf  
} ~}ml*<z@  
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} &fP XU*l4  
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public void run() .y5,x\Pq(  
{ ._:nw=Y0<}  
//获得文件长度 g&/p*c_  
//分割文件 f3*?MXxb16  
//实例FileSplitterFetch K!AAGj`  
//启动FileSplitterFetch线程 .3pbu
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//等待子线程返回 +?D6T!
)  
try{ qf)$$qi  
if(bFirst) C&\5'[*  
{ >XW
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nFileLength = getFileSize(); ,38Eq`5&W  
if(nFileLength == -1) ^cvl:HOog  
{ u~zs* qp  
System.err.println("File Length is not known!"); lb'Cl3H  
} 6~meM@  
else if(nFileLength == -2) DrW#v-d  
{ ^,Ydr~|T  
System.err.println("File is not access!"); <oMUQ*OtV  
} 4B+9z^oQ  
else CDy^UQb  
{ $WQq?
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for(int i=0;i<nStartPos.length;i++) 4IdT'  
{ vm23U^VJ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); O!1Tth
I  
} <msxHw  
for(int i=0;i<nEndPos.length-1;i++) ;)0w:Zn/[  
{ PG5- ;i/  
nEndPos = nStartPos[i+1]; a)-FGP^  
} w>?Un,K  
nEndPos[nEndPos.length-1] = nFileLength; _cDF{E+;  
} _+f+`]iM  
} }}{!u0N},V  
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{.e=qQ%P5)  
//启动子线程 "R #k~R  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; woH)0v  
for(int i=0;i<nStartPos.length;i++) =/Aj  
{ %T`U^Pnr  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s0UFym8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), qd@&59zSh  
nStartPos,nEndPos,i); )4Q?aMm
 
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |w}w.%  
fileSplitterFetch.start(); 6`01EIk  
} hm$X]H`uMX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jZfx Jm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); U$&hZ_A  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", iGXI6`F"  
nEndPos = " + nFileLength); `xS{0P{uj  
// fileSplitterFetch[nPos.length-1].start(); m@Ev~~;  
$9 p!Y}  
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//等待子线程结束 {0\,0*^p  
//int count = 0; Y o
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//是否结束while循环 =(AtfW^H  
boolean breakWhile = false; n_K~vD  
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  \J^  
while(!bStop) omZO+=8Q  
{ -PB[-CX  
write_nPos(); -l+P8:fL~  
Utility.sleep(500); v"u^M-_  
breakWhile = true; ][PzgzG  
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}WFf''Z-  
for(int i=0;i<nStartPos.length;i++) }7<5hn E  
{ Zwt;d5U  
if(!fileSplitterFetch.bDownOver) [K~]&  
{ 3-s}6<0v1  
breakWhile = false; 9W*+SlH@!  
break; >gtQw!  
} >v;8~pgO  
} :y]Omp  
if(breakWhile) Y[ reD  
break; H!e 3~+)  
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//count++; VUU]Pu &  
//if(count>4) &6 -k#r  
// siteStop(); 4tA_YIv  
} Die-@z|Y  
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System.err.println("文件下载结束！"); M s9E@E  
} oj.A,Fh  
catch(Exception e){e.printStackTrace ();} x90*yaw>h  
} e`tLR- &  
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//获得文件长度 s,VXc/  
public long getFileSize() |8_JY2 R  
{
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int nFileLength = -1; %bXx!x8(  
try{ ]6Ug>>x5  
URL url = new URL(siteInfoBean.getSSiteURL()); 6+rlXmd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F^aR+m  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4] > ]-b  
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int responseCode=httpConnection.getResponseCode(); 9D\4n  
if(responseCode>=400) 3{%LS"c  
{ n#Dv2 E=6  
processErrorCode(responseCode); `D7C?M#j]  
return -2; //-2 represent access is error w^k;D,h  
} }]1BO  
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String sHeader; gE/Tj$  
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for(int i=1;;i++) oj,lz?  
{ u#7+U\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Q~D`cc|]  
//Utility.log(in.readLine()); IHfzZHy  
sHeader=httpConnection.getHeaderFieldKey(i); z(uZF3  
if(sHeader!=null) MjfFf} @  
{ \/7i-B]G7  
if(sHeader.equals("Content-Length")) oz'\q0  
{ !M<{E*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 1iT\df  
break; 23(=Xp3;>  
} 73A)lU.  
} 31+;]W=  
else {Ee>n^1  
break; v;#=e$%}MO  
} {@}?k s5  
} .Jb$l$5'w  
catch(IOException e){e.printStackTrace ();} .V9e=yW!*  
catch(Exception e){e.printStackTrace ();} zboF 1v`  
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Utility.log(nFileLength); PALl sGlf  
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return nFileLength; #BK9 k>i  
} xynw8;Y,  
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//保存下载信息（文件指针位置） 5pNY)>]t=  
private void write_nPos() "bg'@:4F  
{ g3@Rl2yQJ  
try{ ;Lw{XqT  
output = new DataOutputStream(new FileOutputStream(tmpFile)); M_0zC1  
output.writeInt(nStartPos.length); 1xNVdI  
for(int i=0;i<nStartPos.length;i++) 7fp(R&)1  
{ ,[p T4G  
// output.writeLong(nPos); bok.j  
output.writeLong(fileSplitterFetch.nStartPos); D*5hrkV9  
output.writeLong(fileSplitterFetch.nEndPos); sGDV]~E  
} j;yf8Nf  
output.close(); &MR/6"/s  
} z9 u$~  
catch(IOException e){e.printStackTrace ();} D;GD<zC]  
catch(Exception e){e.printStackTrace ();} qVjWV$
j  
} 5lKJll^2:  
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//读取保存的下载信息（文件指针位置） {cK^,?x  
private void read_nPos() }y%`)lz~;  
{ o{v&.z  
try{ +1C3`0(  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ph&urxH@  
int nCount = input.readInt(); P27%xV-n>  
nStartPos = new long[nCount]; 3T\l]? z  
nEndPos = new long[nCount]; `"yxdlXA  
for(int i=0;i<nStartPos.length;i++) {C
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{ :WGtR\tK  
nStartPos = input.readLong(); 6SJ"Tni8  
nEndPos = input.readLong(); P=N$qz
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} $FH18  
input.close(); r90+,aLM#?  
} MOn,Db$  
catch(IOException e){e.printStackTrace ();} A% Q!^d  
catch(Exception e){e.printStackTrace ();} ] U@o0  
} -!RtH |P  
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private void processErrorCode(int nErrorCode) ?)Nj c&G  
{ djQv[Vc{  
System.err.println("Error Code : " + nErrorCode); ]e:/"  
} E! /[gZ  
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$
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//停止文件下载 idc`p?XP  
public void siteStop() B@Co'DV[/]  
{ \e=_ 2^v!_  
bStop = true; pD"vRbYF  
for(int i=0;i<nStartPos.length;i++) :6J +%(f  
fileSplitterFetch.splitterStop(); i>L+gLW  
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} m .IU ;cR  
} NE8 jC7  
//负责部分文件的抓取 [,EpN{l  
**FileSplitterFetch.java 6\7ncFO3  
*/ gie
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package NetFox; Z0!5d<  
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import java.io.*; |LG4=j.l  
import java.net.*; k;PA
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public class FileSplitterFetch extends Thread {
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in <(g@Zg  
String sURL; //File URL $yDWu"R8  
long nStartPos; //File Snippet Start Position vgt]:$  
long nEndPos; //File Snippet End Position m~#!  
int nThreadID; //Thread's ID NvE}eA#
 
boolean bDownOver = false; //Downing is over UEs7''6R
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boolean bStop = false; //Stop identical FLal}80.o:  
FileAccessI fileAccessI = null; //File Access interface ~fl@ 2  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]=rht9),"  
{
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this.sURL = sURL; bUV >^d  
this.nStartPos = nStart; ,)+o  
this.nEndPos = nEnd; Jk|Q`h  
nThreadID = id; )C(>H93  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 NqHy%'R  
} {_N,=DQ!  
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public void run() Sgim3):Z  
{ C`=p+2I]  
while(nStartPos < nEndPos && !bStop) L$'[5"ma ;  
{ Tm^89I]L  
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try{ mC&=X6Q]  
URL url = new URL(sURL); uJx"W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yNW\?Z$@q  
httpConnection.setRequestProperty("User-Agent","NetFox"); uY_SU-v  
String sProperty = "bytes="+nStartPos+"-"; 3K&4i'}V  
httpConnection.setRequestProperty("RANGE",sProperty); 84HUBud76Y  
Utility.log(sProperty); c0c|z Ym  
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InputStream input = httpConnection.getInputStream(); jdKOb  
//logResponseHead(httpConnection); I jr\5FA[p  
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byte[] b = new byte[1024]; ^ &E}r{?  
int nRead; -aRU]kIf  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :.(;<b<\  
{ uZa9zs=}c  
nStartPos += fileAccessI.write(b,0,nRead); M7f;Pa  
//if(nThreadID == 1) #ywk|k5z]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M)*\a/6?{  
} W)'*m-I  
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Utility.log("Thread " + nThreadID + " is over!"); (npj_s!.C)  
bDownOver = true; 5tJ,7
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//nPos = fileAccessI.write (b,0,nRead); kP#e((f,  
} A,su;Qh  
catch(Exception e){e.printStackTrace ();} +[\eFj|=  
} ,h|qi[7  
} f~E*Zz`;  
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//打印回应的头信息 6s,uXn  
public void logResponseHead(HttpURLConnection con) ^@P1 JNe  
{ I8oo~2Qw  
for(int i=1;;i++) a`Gx=8  
{ AV 8n(  
String header=con.getHeaderFieldKey(i); "G>3QL+O|  
if(header!=null) >+. (r]  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [{4MR%--  
Utility.log(header+" : "+con.getHeaderField(header)); T0)4v-EO  
else fQrhsuCrC  
break; (mxT2"fC  
} sGvIXD  
} q'pK,uNW  
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public void splitterStop() Uax+dl  
{ 6y%0`!  
bStop = true; Gm*X'[\DD  
} 1[_mEtM:]B  
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} u3Gjg{-N7  
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/* 4|A>b})H  
**FileAccess.java 0$r^C6}f  
*//文件访问(定位，写) ceNix!P  
package NetFox; B^).BQ  
import java.io.*; aq7~QX_0G  
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public class FileAccessI implements Serializable{ fs/*V~@  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 KfF!{g f  
RandomAccessFile oSavedFile; >u9Nz0?j  
long nPos; tabT0  
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public FileAccessI() throws IOException oyo(1>  
{ [qsEUc+Z.'  
this("",0); o\vBOp?hj  
} \EseGgd21  
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public FileAccessI(String sName,long nPos) throws IOException ">?vir^  
{ <\?wAjc,  
oSavedFile = new RandomAccessFile(sName,"rw"); h gJ[LU|>  
this.nPos = nPos; |>@W ]CX[  
oSavedFile.seek(nPos); G[jW
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} iQ{G(^sZN  
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public synchronized int write(byte[] b,int nStart,int nLen) &^4++  
{ z3?o|A}/W  
int n = -1; @k&qb!Qah  
try{ ^*fQX1h<  
oSavedFile.write(b,nStart,nLen); "`N-*;*W  
n = nLen; I%urz!CNE*  
} SwZA6R&  
catch(IOException e) +SJd@y@fR  
{ a22XDes=  
e.printStackTrace (); q+,Q<2J  
} Jmx Ko+-  
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f 2l{^E#h  
return n; G@j0rnn>B  
} hlt[\LP=$  
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} Uix6GT;  
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/* $ImrOf^qt  
**SiteInfoBean.java Y`?-VaY  
*/ Dc)dE2  
package NetFox; s.8{5jVG  
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public class SiteInfoBean { s&j-\bOic9  
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private String sSiteURL; //Site's URL NO :a;  
private String sFilePath; //Saved File's Path rx}r~0i  
private String sFileName; //Saved File's Name D= 7c(  
private int nSplitter; //Count of Splited Downloading File >t7x>_~   
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public SiteInfoBean()  W%\C_  
{//nSplitter的缺省值为5 r7qh>JrO  
//default value of nSplitter is 5 ElUEteZ  
this("","","",5); 6uR^%W8]  
} }NB}"%2  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7%sdtunf`  
{ 0
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sSiteURL= sURL; -IV]U*4  
sFilePath = sPath; ++E3]X|  
sFileName = sName; Z@r.pRr'  
this.nSplitter = nSpiltter; 6^DR0sO  
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} Dwzg/
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public String getSSiteURL() aM;W$1h  
{ ]LM-@G+Jz  
return sSiteURL; 7x<i :x3  
} jRatm.N  
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public void setSSiteURL(String value) k!{p7*0  
{ k?7 X3/O  
sSiteURL = value;
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} e
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public String getSFilePath() LCQE_}Mh  
{ fj&i63?e  
return sFilePath; >]c*'~G&  
} SCTA=l.  
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public void setSFilePath(String value) 'PP#^aI,  
{ ^4o;$u4R  
sFilePath = value; R=KQ  
} vI@%F
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public String getSFileName() qcT'nZ:  
{ ,#8e_3Z$  
return sFileName; n..g~$k  
} e$pMsw'MJ  
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public void setSFileName(String value) 
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{ QeK*j/  
sFileName = value; @62Mk},9 c  
} l(Q?rwI8Y  
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public int getNSplitter() 95
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{ F_4n^@M  
return nSplitter; ^k\e8F/  
} p l&Muv  
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public void setNSplitter(int nCount) b4pm_Um  
{ 1w&!H]%{  
nSplitter = nCount; *2X0^H|dS  
} 3=L.uXVb  
} Ft!],n-n*  
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/* 71{p+3Z&  
**Utility.java k|!EDze43?  
*/ O &-wxJ]S  
package NetFox; ]H1I,`=@  
9cj9SB4  

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public class Utility { %?Ev|:i`@  
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public Utility() 6!(@@^7{*  
{ Q0ON9gqqv  
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} k Zq!&  
+) m_o"hl  
//线程睡眠 Pp5^@A  
public static void sleep(int nSecond) lO_UPC\@fw  
{ %p0xM  
try{ k{Aj^O3gD  
Thread.sleep(nSecond); icgSe:Ci  
} F
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catch(Exception e) mOlI#5H  
{ ze]h..,]K  
e.printStackTrace (); yiA<,!;4P  
} _:"<[ >9  
} Dv/WE>?Aw  
D N*t~Z3[  
//日志 eh5gjSqx  
public static void log(String sMsg) 0p\@!Z H  
{ I2nhqJy^  
System.err.println(sMsg); I'0@viF"Nx  
} qC?:*CXH  
b 'pOJ
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public static void log(int sMsg) UCClWr  
{ go<W(
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System.err.println(sMsg); [bk?!0]aV  
} KFwzy U"  
} yu/`h5&*  
|1>*;\o-  
JC3m.)/  
/* >L 0_dvr  
**TestMethod.java 1OF& *  
*/ E3iW-B8u8  
package NetFox; :B:"NyPA  
6 M*O{f
 

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public class TestMethod { byfJy^8G  
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 MEGv}  
public TestMethod() *^wm1|5  
{ ///xx/weblogic60b2_win.exe IDG}Z
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try{ \9g+^vQ
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *NClfkZ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); YS%h^>I^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); GJqJlgHe  
fileFetch.start(); \0f{S40  
} W0]gLw9*  
catch(Exception e){e.printStackTrace ();} 5qP:/*+  
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} SK#(#OQoh  
*9{Z$IA9w  
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public static void main(String[] args) '5|h)Q5  
{ `p;I}  
new TestMethod(); 9Q+'n$s0^  
} la+[bm<v  
} SrK)t.oK  
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