http断点续传简单实现（java)

/* UbYKiLDF)  
**SiteFileFetch.java P;y/`_jo  
*/ xp&I~YPH  
package NetFox; 9rid98~d  
import java.io.*; q O
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import java.net.*; m0#hG x  
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public class SiteFileFetch extends Thread { s=d?}.E$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean J\{)qJ*jp  
long[] nStartPos; //开始位置 $_ NaxV  
long[] nEndPos; //结束位置 D{4 Y:O&J  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <T}#>xHs3  
long nFileLength; //文件长度 Vnl~AQfk|  
boolean bFirst = true; //是否第一次取文件 \vT8 )\  
boolean bStop = false; //停止标志 ^ID%pd  
File tmpFile; //文件下载的临时信息 

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DataOutputStream output; //输出到文件的输出流 %*/[aq,#  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） =DCQ!02  
public SiteFileFetch(SiteInfoBean bean) throws IOException /# eBDo  
{ Ltj}>.+  
siteInfoBean = bean; l-Xx
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RS:0xN\JN  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); MVj@0W33m  
if(tmpFile.exists ()) k]JL
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{ s R~&S))  
bFirst = false; %z.G3\s0  
read_nPos(); %z2nas$$g  
} F+6ZD5/  
else DTJ  
{ Ky'^AN]  
nStartPos = new long[bean.getNSplitter()]; u)V*o  
nEndPos = new long[bean.getNSplitter()]; PQ[TTLG\&  
} K4rr.f6  
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} _x \Ll?,  
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public void run() WDX?|q9rCt  
{ ;e{2?}#8&  
//获得文件长度 kj8zWG4KH  
//分割文件 `SG70/  
//实例FileSplitterFetch u1"e+4f  
//启动FileSplitterFetch线程 9@j~1G%^  
//等待子线程返回 <V,?!}V  
try{ l&rDa=m.J  
if(bFirst) [0}471  
{ 5>=tNbk"s  
nFileLength = getFileSize(); eS"gHldz  
if(nFileLength == -1) Brl6r8LGi  
{ EvYw$
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System.err.println("File Length is not known!"); <Kh\i'8  
} ZJ4"QsF  
else if(nFileLength == -2) ! $iR:ji  
{ ^4[\-L8Lpq  
System.err.println("File is not access!"); NqWHR~&  
} 3UaP7p+d  
else j\vK`.z  
{ JTI m`t"d=  
for(int i=0;i<nStartPos.length;i++) . 9 NS  
{ q!,do2T  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); D;L :a`Y  
} ZMe|fn  
for(int i=0;i<nEndPos.length-1;i++) 3x'30  
{ ky#6M? \  
nEndPos = nStartPos[i+1]; e\dT~)c  
} sV6A& Aw  
nEndPos[nEndPos.length-1] = nFileLength; 2eK\$_b_  
} y((_V%F}  
} R*y[/Aw  
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//启动子线程 {aL$vgYT1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; EH3G|3^xz  
for(int i=0;i<nStartPos.length;i++) yI%> w4Z  
{ EzyIsp> _  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WU4i-@Bm8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), KCFwO'  
nStartPos,nEndPos,i); mx[^LaR>v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o`U\Nhq  
fileSplitterFetch.start(); VB#31T#q?  
} @
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KCu6:)6'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); oL@ou{iQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -7$'* V9$  
nEndPos = " + nFileLength); {q)B@#p
 
// fileSplitterFetch[nPos.length-1].start(); JXAyF6 $  
16y$;kf8  
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//等待子线程结束 gh}AD1TN]  
//int count = 0; z|<oxF.  
//是否结束while循环 ]Yu+M3Fq  
boolean breakWhile = false; _HK&KY  
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while(!bStop) D5>~'N3b  
{ ]*@$%iCPE  
write_nPos(); !VHIl&Mos  
Utility.sleep(500); t/1NTa  
breakWhile = true; WK}+f4tdW[  
=QfKDA  
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for(int i=0;i<nStartPos.length;i++) 9/M!S[N9  
{ ?>8zU;Aj  
if(!fileSplitterFetch.bDownOver) #[W[|m  
{ I`TD*D  
breakWhile = false; !S!03|  
break; EAB+kY  
} K)+l6Q  
} LPn}QzH  
if(breakWhile)
#<PdZl
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break; 5Nb_K`Vp*  
#}(Df&  
|w2AB7EU  
//count++; }#x3IE6'  
//if(count>4) g)A0PvEu  
// siteStop(); fB96Q  
} 1.H!A@  
RG3G},Q   
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System.err.println("文件下载结束！"); bW^QH-t  
} 3x0wk9lND  
catch(Exception e){e.printStackTrace ();} KL mB  
} -C}59G8  
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//获得文件长度 b=UMoWS  
public long getFileSize() 4.B*B3  
{ j2 ^T:q[  
int nFileLength = -1; l&Ghs@>Kl  
try{ Vk_&W.~  
URL url = new URL(siteInfoBean.getSSiteURL()); t)Q@sKT6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ('-}"3  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?1:/ 6  
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int responseCode=httpConnection.getResponseCode(); YiuOu(X  
if(responseCode>=400) WkySTc  
{ %`'z^W  
processErrorCode(responseCode); r)]CZ])  
return -2; //-2 represent access is error |Du13i4].&  
} ,M&0<k\  
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String sHeader; {U '&9_y  
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for(int i=1;;i++) +7<>x-+  
{ ]MLLr'6?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); y6Epi|8  
//Utility.log(in.readLine()); !K3cf]2UD  
sHeader=httpConnection.getHeaderFieldKey(i); (E}cA&{  
if(sHeader!=null) m'(;uR`  
{ >X,A
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if(sHeader.equals("Content-Length")) KBRg95E~]l  
{ ;3}EBcw)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *\:_o5o%[T  
break; eQVPxt2N  
} d3G{0PX  
} 50GYL5
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else O;e8ft '|  
break; e_k _ty`  
} FT/5 _1i  
} o-=d|dWG  
catch(IOException e){e.printStackTrace ();} FNm6/_u3  
catch(Exception e){e.printStackTrace ();} d<Q+D1  
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Utility.log(nFileLength); hJo^Wo  
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return nFileLength; ,Q=)$ `%  
} Eh@T W%9*  
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//保存下载信息（文件指针位置） Rs F3#H  
private void write_nPos() G(OT"+O,  
{ NC.P2^%  
try{ QYTTP6 Gz+  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $#7J\=GZ+  
output.writeInt(nStartPos.length); 4%fN\f  
for(int i=0;i<nStartPos.length;i++) y{`(|,[  
{ Ls>u`hG  
// output.writeLong(nPos); 8yWu{'G
 
output.writeLong(fileSplitterFetch.nStartPos); +8)]m<  
output.writeLong(fileSplitterFetch.nEndPos); 8f,'p}@!d  
} mo#0q&ZQ  
output.close(); ,B~lwF9  
} ;*-@OLT_K  
catch(IOException e){e.printStackTrace ();} 45)ogg2  
catch(Exception e){e.printStackTrace ();} E/7vIg F  
} qbU1qF/  
,|.*,  
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//读取保存的下载信息（文件指针位置） FQ^<,  
private void read_nPos() l!;_lH8W$  
{ F!)M<8jL&9  
try{ ZcTL#OTP  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); c2/R]%`)9  
int nCount = input.readInt(); EID)o[<
  
nStartPos = new long[nCount]; Z6R: rq  
nEndPos = new long[nCount]; N* ] i G~  
for(int i=0;i<nStartPos.length;i++) B)"#/@!bHH  
{ =(.mf  
nStartPos = input.readLong(); Rnj Jg?I=  
nEndPos = input.readLong(); 5]H))}9>d
 
} -4vHK!l  
input.close(); YBtq0c  
} "y~muE:.
 
catch(IOException e){e.printStackTrace ();} UbY~xs7_  
catch(Exception e){e.printStackTrace ();} f3zfRhkIk  
} :m*!?QGdL  
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private void processErrorCode(int nErrorCode) fVH*dX'Jz  
{ }$Hs;4|  
System.err.println("Error Code : " + nErrorCode); \[[TlB>  
} d=t}T6.|  
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//停止文件下载 CGd[3}"  
public void siteStop() GJC!0{8;  
{ >[|GC/
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bStop = true; 8O8\q ;US  
for(int i=0;i<nStartPos.length;i++) ;]gsJ9FK<  
fileSplitterFetch.splitterStop(); :F^$"~(,  
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} 8! H8[J  
} @],6SKbG6  
//负责部分文件的抓取 X,WQ'|rC  
**FileSplitterFetch.java I|KY+k> /  
*/ 8h&oSOkQk,  
package NetFox; hv$uH7Fz  
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import java.io.*; }osHA`x"2  
import java.net.*; dThR)Z'=  
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public class FileSplitterFetch extends Thread { q+A<g(Xu  
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String sURL; //File URL MkG`w,  
long nStartPos; //File Snippet Start Position k9}Q7)@  
long nEndPos; //File Snippet End Position t] r,9df'  
int nThreadID; //Thread's ID });cX$  
boolean bDownOver = false; //Downing is over ^))PCn_zb  
boolean bStop = false; //Stop identical u}K5/hC  
FileAccessI fileAccessI = null; //File Access interface 35Ai;mU'  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException zwM"`z  
{ :y+B;qw  
this.sURL = sURL; 6=ZRn gQ  
this.nStartPos = nStart; Q`.'-iq  
this.nEndPos = nEnd; xwTijSj  
nThreadID = id; `z9)YH  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 2d-TU_JqX  
} VHXI@UT*  
"gXxRHTX  
/=8O&1=D  
public void run() >I$B=  
{ dT5J-70Fl  
while(nStartPos < nEndPos && !bStop) &`9j)3^J.  
{ e>L5.~i  
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try{ Ik`O.Q.}  
URL url = new URL(sURL); <8u>_
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); o3Mf:;2cC  
httpConnection.setRequestProperty("User-Agent","NetFox"); BZovtm3E  
String sProperty = "bytes="+nStartPos+"-"; b8rp8'M)  
httpConnection.setRequestProperty("RANGE",sProperty); W|)GV0YM  
Utility.log(sProperty); oN *SRaAp  
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InputStream input = httpConnection.getInputStream(); QCeMKjCmY  
//logResponseHead(httpConnection); H@K#|A=a  
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byte[] b = new byte[1024]; F(#haJ$>  
int nRead; \Dn&"YG7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) z%OuI 8"'  
{ qBT_! )h   
nStartPos += fileAccessI.write(b,0,nRead); &MCy.(jN  
//if(nThreadID == 1) L +L9Y}  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); #v{Y=$L  
} T"n{WmVQ  
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Utility.log("Thread " + nThreadID + " is over!"); 8O,?|c=>  
bDownOver = true; ^'m\D;
 
//nPos = fileAccessI.write (b,0,nRead); *6:v}#b[  
} ^#]c0  
catch(Exception e){e.printStackTrace ();} ?nQ_w0j  
} _b>F#nD,'%  
} ):e+dt  
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2zz,(RA  
//打印回应的头信息 j:7*3@f  
public void logResponseHead(HttpURLConnection con) 9lKn%|=T  
{ >xT^RYS  
for(int i=1;;i++) }$l8d/_$[  
{ e"]"F{Q  
String header=con.getHeaderFieldKey(i); Eu|sWdmf l  
if(header!=null) TI}}1ScA'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {S 
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Utility.log(header+" : "+con.getHeaderField(header)); *D2Nm9sl  
else +}P%HH]E/p  
break; <"<Mbbp  
} 85'nXYN{d  
} Y=r!2u6r~  
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public void splitterStop()
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{ Rq) 0i}F  
bStop = true; d^PD#&"g  
} :4|M jn  
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} 1!vPc93 $$  
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/* hi!`9k  
**FileAccess.java %dc3z"u  
*//文件访问(定位，写) %;7.9%  
package NetFox; ]nQ+nH  
import java.io.*; I"-dTa  
#<4--$Xo  
</= CZy5w  
public class FileAccessI implements Serializable{ 5y]io Jc9-  
r088aUO P  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^5>s7SGB"  
RandomAccessFile oSavedFile; $_sYfU9  
long nPos; C}q>YRubZ  
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public FileAccessI() throws IOException qe?Qeh(!X  
{ +Gow5-(  
this("",0); 
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} []zua14F6  
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public FileAccessI(String sName,long nPos) throws IOException <?YA,"~  
{ 9t?L\
  
oSavedFile = new RandomAccessFile(sName,"rw"); Vo\H<_=
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this.nPos = nPos; 1_uvoFLk  
oSavedFile.seek(nPos); tmO`|tn&  
} eJHp6)2  
6g"C#&{@  
>"%ob,c:#  
public synchronized int write(byte[] b,int nStart,int nLen) {pWBwf>R C  
{ 6W&_2a7*  
int n = -1; ?1peF47Z
 
try{ zPR8f-Uvw  
oSavedFile.write(b,nStart,nLen); %m eLW&  
n = nLen; ?DPHo)w  
} eCWPhB6l  
catch(IOException e) dQD$K|aUp  
{ sHdp  
e.printStackTrace (); _\\ -md:  
} M(enRs3`O  
$ KB  
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return n; }^Gd4[(,g  
} :_xh(W+2<  
io
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{:bN/zV#  
} 0}]SUe^  
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/* e"k/d<  
**SiteInfoBean.java OX\$nQ\o  
*/ QB&BTT=!  
package NetFox; T_LLJ
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public class SiteInfoBean { ]a?bzOr,  
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private String sSiteURL; //Site's URL 7C7>y/uS  
private String sFilePath; //Saved File's Path Q9c)k{QZ  
private String sFileName; //Saved File's Name #H~_K}Ks  
private int nSplitter; //Count of Splited Downloading File \S ."?!U  
booRrTS  
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public SiteInfoBean() M:n6BC>t"  
{//nSplitter的缺省值为5 ~Y7dH Dn  
//default value of nSplitter is 5 =sgdkAYwP  
this("","","",5); 2'|8Q\,:4Z  
} QA?oJ_}y  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /Vww?9U;  
{ y9L14  
sSiteURL= sURL; %w ) +V  
sFilePath = sPath; O=}g4c  
sFileName = sName; g`0moXz  
this.nSplitter = nSpiltter; nlGHT  
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T%IK/"N|+  
} ^YlI>_3s  
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public String getSSiteURL() gb" 4B%Hm  
{ DHw<%Z-J  
return sSiteURL; ~F!,PM/  
} H:QhrL+7_  
V
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public void setSSiteURL(String value) w0lT%CPx  
{ fCw*$:O  
sSiteURL = value; ;11x"S  
} *[}^[J x  
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public String getSFilePath() ,Nm$i"Lg  
{ f&KdlpxKv  
return sFilePath; ~h$wH{-U#  
} -ijC_`>  
6'vbT~S!  
.; Q:p*  
public void setSFilePath(String value) `3cCH  
{ uLR<FpM  
sFilePath = value; vB'>[jvA|  
} 6%Mt  
12UD19!  
m Y,|J\w@  
public String getSFileName() K.~q+IYP[  
{ 3Q^fVn$tk  
return sFileName; E_T2z4lw  
}
==N{1gO]  
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public void setSFileName(String value) pzZk\-0R  
{  #
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sFileName = value; q5DEw&UZJ  
} H`9Uf)  
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public int getNSplitter() \ 0W!4
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{ zUJZ`seF  
return nSplitter; <
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} p>w]rE:}  
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public void setNSplitter(int nCount) o5U(
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{ AIYmS#V1W2  
nSplitter = nCount; WJH\~<{mP  
} !]yO^Ob.E  
} KngTc(^_D  
942lSyix  
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/* j=RRfFg)  
**Utility.java o\b-_E5"?  
*/ 2_^aw[-  
package NetFox; w obgu  
MK#wut  
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public class Utility { 8.AR.o  
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uo%P+om_}  
public Utility() l7H qo)  
{ Yy
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"TyJP[/  
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} q[q?hQ/b  
RD7^&  
//线程睡眠 sUJ%x#u}Fk  
public static void sleep(int nSecond) )SF}2?7e  
{ `{k"8#4:qA  
try{ 1RcSTg  
Thread.sleep(nSecond); U1_@F$mq<  
} P262Q&.}d  
catch(Exception e) H,fZ!8(A_)  
{ v{zMO:3  
e.printStackTrace (); }/tf>?c  
} #'D" 'B  
} eV:9y  
C?v[Z]t  
//日志 ZYU=\  
public static void log(String sMsg) `*", <  
{ 6tHO!`}1  
System.err.println(sMsg); M5nWVK7c  
} )c n+1R  
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N'r3`8tS  
public static void log(int sMsg) F:@70(<w%  
{ [FA{x?vkf  
System.err.println(sMsg); 0R{dNyh{  
} ('wY9kvL&  
} &qpr*17T  
1tTgP+  
(~CLn;'  
/* AjcX  N  
**TestMethod.java MYJg8 '[j  
*/ @k[R/,#'[t  
package NetFox; L^2FQti>  
dm0QcW4  
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public class TestMethod { fkf1m:Ckh  
S}APQ  
JD@J[YY5R  
public TestMethod() 2 rw%H  
{ ///xx/weblogic60b2_win.exe A8oo@z68n>  
try{ '~&9D:(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L.jh   
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); CkdP#}f  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^7 &5 z&o  
fileFetch.start(); Ipq"E  
} |Y[wzDYV  
catch(Exception e){e.printStackTrace ();} d+Ek%_  
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jN6uT&{T  
} ~=
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public static void main(String[] args) Y[$!`);Ye  
{ \8?Tdx=  
new TestMethod(); .xH5fMj,"  
} 83Q4On  
} (
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