http断点续传简单实现（java)

/* : ,0F_["3  
**SiteFileFetch.java sL;  
*/ }n!$)W*?  
package NetFox; azEN_oUV  
import java.io.*; "pQFIV,  
import java.net.*; ]yc&ffe%  
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public class SiteFileFetch extends Thread { Ancka  
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SiteInfoBean siteInfoBean = null; //文件信息Bean K)e;*D  
long[] nStartPos; //开始位置 {#-I;I:  
long[] nEndPos; //结束位置 '/2u^&W  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 pDw^~5P  
long nFileLength; //文件长度 BKd03s=  
boolean bFirst = true; //是否第一次取文件 |wef[|@%  
boolean bStop = false; //停止标志 |f9fq~'1e  
File tmpFile; //文件下载的临时信息 2P&KU%D)0s  
DataOutputStream output; //输出到文件的输出流 <oFZFlY@  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） E=G"_ ^hCE  
public SiteFileFetch(SiteInfoBean bean) throws IOException Zo
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{ I.C,y\  
siteInfoBean = bean; NeG$;z7  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 75>)1H)Xm  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); h-0#h/u>M  
if(tmpFile.exists ()) puv/+!q  
{ W~EDLLZ  
bFirst = false; uyE_7)2d  
read_nPos(); M/!5r  
} aPR0DZ@  
else \=3fO(  
{ n@`D:;?{  
nStartPos = new long[bean.getNSplitter()]; E{):zg  
nEndPos = new long[bean.getNSplitter()]; etcpto=Mo  
}
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} |sG@Ku7~4  
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public void run() df
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{ Iu3*`H  
//获得文件长度 F<W`zQ46  
//分割文件 :6N'%LKK  
//实例FileSplitterFetch h'QEwW  
//启动FileSplitterFetch线程 d]fo>[%Xr  
//等待子线程返回 ")gd)_FOS  
try{ GjHV|)^  
if(bFirst) ap 5D6y+  
{ .}xF2'~E/  
nFileLength = getFileSize(); E%+aqA)f  
if(nFileLength == -1) IJ#G/<ZJZ  
{ _^Ds[VAgA  
System.err.println("File Length is not known!"); (]Zyk,[  
} {\r1A  
else if(nFileLength == -2) 0=WZ 8|R  
{ Q!%C:b  
System.err.println("File is not access!"); I;=HXL  
} 8!{;yz  
else 5.]eF$x2  
{ D&)w =qIu  
for(int i=0;i<nStartPos.length;i++) |i/Iv  
{ |I0O|Zdv  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Q&JnF`*  
} U]8 @  
for(int i=0;i<nEndPos.length-1;i++) Ao2m"ym  
{ 49e~/YY  
nEndPos = nStartPos[i+1]; equ|v~@y  
} r[u@[  
nEndPos[nEndPos.length-1] = nFileLength; >TnV Lx<  
} E~b Yk6  
} 2r0u[  
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//启动子线程 v/1&V+"^kd  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^GS,4[)H  
for(int i=0;i<nStartPos.length;i++) Bo
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{ {}Q A#:V  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u'm[wjCjc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ?E6*Ef  
nStartPos,nEndPos,i); Pc{0Js5VzE  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o3s ME2  
fileSplitterFetch.start(); ]<Ugg  
} Q5!"tFp  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CO)BF%?B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /d1 B-I  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", sF+mfoMtG  
nEndPos = " + nFileLength); >$%rsc}^  
// fileSplitterFetch[nPos.length-1].start(); Os9;;^k  
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//等待子线程结束 e>GX]tK  
//int count = 0; QcXqMx  
//是否结束while循环 ME9jN{ le  
boolean breakWhile = false; =}8:zO 2'{  
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while(!bStop) ,j'>}'wG)  
{ N1pw*<&  
write_nPos(); 88]UA  
Utility.sleep(500); Zn-F!Lsv  
breakWhile = true; 0\Q/$#3  
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for(int i=0;i<nStartPos.length;i++) s={jwI50  
{ @@]
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if(!fileSplitterFetch.bDownOver) BB>R=kt  
{ ^hMJNy&R  
breakWhile = false; X}-)io  
break; @$e!|.{1q  
} szDd!(&pv  
} L{2KK]IF  
if(breakWhile) 3T<aGW1  
break; RV&=B%w+  
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//count++; 9"#,X36  
//if(count>4) +O2z&a;q  
// siteStop(); j9bn|p$DA  
} ,rC$~ &  
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System.err.println("文件下载结束！"); (b]r_|'  
} b/yXE)3 X  
catch(Exception e){e.printStackTrace ();} | M|5Nc>W  
} AJ:(NV1=  
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//获得文件长度 {hE\ECT-  
public long getFileSize() =/|2f
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{ U^x
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int nFileLength = -1; npJyVh47  
try{ 3Dm`8Xt  
URL url = new URL(siteInfoBean.getSSiteURL()); 7M#irCX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $v6`5;#u  
httpConnection.setRequestProperty("User-Agent","NetFox"); `!JcQ'u  
#
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int responseCode=httpConnection.getResponseCode();  /uyZ[=5  
if(responseCode>=400) 2brxV'tk  
{ |#)S`Ua1  
processErrorCode(responseCode); {FrcpcrQa  
return -2; //-2 represent access is error %]iDhXLr  
} $4&%<'l3I  
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String sHeader; (PM!{u=  
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for(int i=1;;i++) XITh_S4fs=  
{ `E4+#_ v  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); qkg`4'rLg  
//Utility.log(in.readLine()); 1 po.Cmx  
sHeader=httpConnection.getHeaderFieldKey(i); t}!Y}D  
if(sHeader!=null) o~(/Twxam  
{ pSzO)j  
if(sHeader.equals("Content-Length")) x9U(,x6r  
{ q\`0'Z,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >7[o=!^:4  
break; Vzs_g]V  
} Q8~|0X\
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} DC5^k[m  
else S%sD#0l  
break; |P
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} Ow@}6&1  
} /jtU<uX  
catch(IOException e){e.printStackTrace ();} v{T%`WuPRf  
catch(Exception e){e.printStackTrace ();} rZK;=\Ot  
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Utility.log(nFileLength); ZliJc7lss  
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return nFileLength; 5xsGSoa+  
} Kz>Bw;R(  
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//保存下载信息（文件指针位置） >p[skN 
 
private void write_nPos() lO>9Q]S<  
{ -fA1_ ?7S  
try{ ?4^8C4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +IM:jrT(  
output.writeInt(nStartPos.length); ],3#[n[ m  
for(int i=0;i<nStartPos.length;i++) c=52*&  
{ ma%PVz`I;9  
// output.writeLong(nPos); W{v{sQg  
output.writeLong(fileSplitterFetch.nStartPos); cu~\&3R  
output.writeLong(fileSplitterFetch.nEndPos); lQ]8PR t8  
} K!\$MBI  
output.close(); V?0Yzg$sy  
} ]nM 2J}7  
catch(IOException e){e.printStackTrace ();} Wt,t5  
catch(Exception e){e.printStackTrace ();} 
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} B}&9+2M  
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//读取保存的下载信息（文件指针位置） L (#DVF  
private void read_nPos() z^etH/]Sy  
{ xeGl}q|  
try{ (z:DT
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;L{#TC(]J]  
int nCount = input.readInt(); EW:tb-%`  
nStartPos = new long[nCount]; Wj}PtQ%lp/  
nEndPos = new long[nCount]; V(5=-8k  
for(int i=0;i<nStartPos.length;i++) |RA|nu   
{ G)S(a4  
nStartPos = input.readLong(); ayR;|S  
nEndPos = input.readLong(); !=f$ [1  
} !gKz=-C  
input.close(); 1\{_bUZ&  
} R'Uw
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catch(IOException e){e.printStackTrace ();} eM1=r:jgE  
catch(Exception e){e.printStackTrace ();} &{5v[:$  
} N"M?kk,  
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private void processErrorCode(int nErrorCode) }nO[;2Na  
{ M#?^uu'  
System.err.println("Error Code : " + nErrorCode); p3L0'rY|+  
} J,&B
 
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//停止文件下载 #@v$`Df<  
public void siteStop() GcpAj9  
{ G8Qo]E9-/  
bStop = true; !idQ-&  
for(int i=0;i<nStartPos.length;i++) jlA?JB  
fileSplitterFetch.splitterStop(); yW!+:y_N_  
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} dm+}nQI\  
} @#?w>38y  
//负责部分文件的抓取 5'mpd  
**FileSplitterFetch.java 1vG]-T3VC  
*/ =/6rX"\P  
package NetFox; pp!>:%  
1/l;4~p7'  
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import java.io.*; c'LDH
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import java.net.*; s.8]qQRr  
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public class FileSplitterFetch extends Thread { sgRD]SF  
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String sURL; //File URL 3SU:Xd(\o  
long nStartPos; //File Snippet Start Position y=H\Z/=  
long nEndPos; //File Snippet End Position B\ITXmd   
int nThreadID; //Thread's ID @[vwqPOL  
boolean bDownOver = false; //Downing is over VZRM=;V  
boolean bStop = false; //Stop identical O6Gg?j  
FileAccessI fileAccessI = null; //File Access interface !K~L&.\T  
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@
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \kQ@G  
{ )HFl 0[vT  
this.sURL = sURL; R DAihq  
this.nStartPos = nStart; {TWgR2?{C  
this.nEndPos = nEnd; zq?
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nThreadID = id; ;Bs^+R7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 3H'+7
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} (K}Md~  
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} XJZw|n  
public void run() \i +=tGY  
{ MUs~ZF  
while(nStartPos < nEndPos && !bStop) #;#r4sJwU  
{ R'.YE;leBG  
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try{ 2S{IZ]  
URL url = new URL(sURL); c[DC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ju@5D h  
httpConnection.setRequestProperty("User-Agent","NetFox"); G|"`kAa  
String sProperty = "bytes="+nStartPos+"-"; [p%OIqC`pB  
httpConnection.setRequestProperty("RANGE",sProperty); oV7A"8L^a  
Utility.log(sProperty); [)ybPIv]  
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InputStream input = httpConnection.getInputStream(); u\]aUP e  
//logResponseHead(httpConnection); ,XZ[L? >  
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byte[] b = new byte[1024]; 7T)J{:+0!|  
int nRead; pKM5<1J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) q%/ciPgE  
{ g3i !>  
nStartPos += fileAccessI.write(b,0,nRead); IIW6;jS  
//if(nThreadID == 1) 1 ^k#g,  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;h }^f-  
} -XSu;'4q  
09RJc3XE9  
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Utility.log("Thread " + nThreadID + " is over!"); j+p=ik  
bDownOver = true; }g?9/)z  
//nPos = fileAccessI.write (b,0,nRead); wJb\Q  
} A^a9,T  
catch(Exception e){e.printStackTrace ();} 1Xv- e8M  
} /^d!$v  
} #&hu-gMV  
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//打印回应的头信息 'yWv @)  
public void logResponseHead(HttpURLConnection con) bN#)F    
{ ]('isq,P  
for(int i=1;;i++) r}gp{Pf7e  
{ t-vH\m  
String header=con.getHeaderFieldKey(i); & q(D90w.  
if(header!=null) ~IB~>5U!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (aO+7ykRuJ  
Utility.log(header+" : "+con.getHeaderField(header)); .-:R mYGR  
else `GG PkTN  
break; S"Q$ Ol"  
} oXR%A7  
} qP"<vZ  
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public void splitterStop() n{~Ws^d  
{ Y^?J3[@  
bStop = true; }tIIA"dZ  
} tXocGM{6C  
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} ,UdTUw~F  
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/* xl(];&A3  
**FileAccess.java Z'%k`F  
*//文件访问(定位，写) vM}oxhQ$n  
package NetFox; C#5z!z/:%  
import java.io.*; C?Sy90f  
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public class FileAccessI implements Serializable{ [hf#$Dl|  
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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 FS%Xq-c  
RandomAccessFile oSavedFile; 0<+=Ew5Z  
long nPos; crJyk#_  
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public FileAccessI() throws IOException W*hRYgaX3  
{ H1,;Xrm  
this("",0); *Mt's[8  
}  \|Qx`-  
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public FileAccessI(String sName,long nPos) throws IOException Z[baQO  
{ )w8h2=l  
oSavedFile = new RandomAccessFile(sName,"rw"); ,H3~mq]  
this.nPos = nPos; 6'e}!O  
oSavedFile.seek(nPos); "%
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} qbjLTE=  
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public synchronized int write(byte[] b,int nStart,int nLen) nlsQf3  
{ '3f"#fF6  
int n = -1; ]@W.5!5H  
try{ ,X&lVv#  
oSavedFile.write(b,nStart,nLen); ?qviJDD|f  
n = nLen; `e t0i.  
} P9/5M4]tt  
catch(IOException e)
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{ z?HP%g'M~  
e.printStackTrace (); Y~T;{&wi  
} K.cMuh  
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return n; 'H<0:bQ=I  
} D7b<&D@  
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} Kr!(<i  
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/* vMsb@@O\\  
**SiteInfoBean.java \gRX:i#n  
*/ ( w(GJ/g  
package NetFox; O|J`M2r  
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public class SiteInfoBean { he0KzwBF  
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private String sSiteURL; //Site's URL }vkrWy^  
private String sFilePath; //Saved File's Path |->{NUZ{  
private String sFileName; //Saved File's Name oagxTFh8~  
private int nSplitter; //Count of Splited Downloading File q/Dc*Qn m  
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public SiteInfoBean() 12*'rU;*  
{//nSplitter的缺省值为5 AvdxDN  
//default value of nSplitter is 5 P agzp%m  
this("","","",5); d/G`w{H}y  
} =j]us?5  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |:SBkM,  
{ 1;<J] S$$  
sSiteURL= sURL; T8
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sFilePath = sPath; u+eA>{  
sFileName = sName; 7a
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this.nSplitter = nSpiltter; zhbp"yju7  
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} `y; s1nL  
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public String getSSiteURL() E.]sX_X?  
{ 7pDov@K<{  
return sSiteURL; h V@C|*A  
} <JE-#i  
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public void setSSiteURL(String value) sw{,l"]<  
{ 76a+|TzR  
sSiteURL = value; vr<6j/ty  
} $}0q=Lg%wv  
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public String getSFilePath() "Zd4e2>{M\  
{ B#'TF?HUEn  
return sFilePath; 4:-h\%  
} !uLW-[F,  
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public void setSFilePath(String value) R9Wh/@J]  
{ W8j)2nKD  
sFilePath = value; L DD^X@q  
} OI"vC1.5  
/gZrnd?  
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public String getSFileName() 0UeDM*  
{ $e#p -z  
return sFileName; l\7NR  
} '+1<7jl&I  
s0"S;{_#  
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public void setSFileName(String value) =D.M}xqo  
{ :nYl]Rm  
sFileName = value; #W,BUN}  
} =s`\W7/;{-  
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public int getNSplitter() w(pLU$6X  
{ |LA./%U  
return nSplitter; xoI;s}*E  
} [{e[3b*M|  
2%"2~d7  
}Z*@EWc>  
public void setNSplitter(int nCount) +L1%mVq]y  
{ I#QBJ#  
nSplitter = nCount; !_rAAY  
} [=079UN-X  
} a9PSg/p  
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/* ZKTOif}  
**Utility.java UA$ XjP  
*/ n5dFp%k  
package NetFox; O,6Upk  
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public class Utility { mh;<lW\K/Z  
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public Utility() )O~LXK=b  
{ Iih~W&  
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} z?`&HU Nf  
>oi`%V  
//线程睡眠 \G}EI|Wo  
public static void sleep(int nSecond) #UL:#pY  
{ 22S4q`j  
try{ }I<r=?  
Thread.sleep(nSecond); 9X&Xc  
} &1Dq3%$c  
catch(Exception e) @ qWgokf  
{ =jIB5".  
e.printStackTrace (); T X.YTU  
} _cdrz)T  
} +@[T0cXp  
s7=CH  
//日志 V8ka*VJ(B  
public static void log(String sMsg) 'EoJo9p6}  
{ :4s{?IY
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System.err.println(sMsg); :GXiA  
} ?.E6Ube  
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public static void log(int sMsg) HbQ `b  
{ 'PRsZ`x.  
System.err.println(sMsg); R=P=?U.  
} Y`jvza%  
} :xISS  
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/* I\E`xkbBu  
**TestMethod.java !Kr|04Qp#x  
*/ Q!8AFLff4  
package NetFox; \}Fx''  
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public class TestMethod { xo2PxU
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public TestMethod() Yy`\??,  
{ ///xx/weblogic60b2_win.exe p2 u*{k{  
try{ 9}4P%>_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Jm&7&si7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); GJN"43  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0zfh:O  
fileFetch.start(); ek!x:G$'  
} N9hs<b+N_  
catch(Exception e){e.printStackTrace ();} 7l}P!xa&  
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} ;0DTf  
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public static void main(String[] args) l&l&
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{ a@:(L"Or  
new TestMethod(); :VpRpj4f  
} o1<Y#db[  
} 4ti\;55{W  
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