http断点续传简单实现（java)

/* v2>Dn=V  
**SiteFileFetch.java UJ&gm_M+kL  
*/ tk+t3+  
package NetFox; a*o k*r  
import java.io.*; 3e|,Z'4}4  
import java.net.*; {InW%qSn_  
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public class SiteFileFetch extends Thread { /$UWTq/C7  
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SiteInfoBean siteInfoBean = null; //文件信息Bean 9YwS"~Q =w  
long[] nStartPos; //开始位置 =jvN8R*[  
long[] nEndPos; //结束位置 ^;cJjl'=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Kxsj_^&|i  
long nFileLength; //文件长度 J 77*Ue^  
boolean bFirst = true; //是否第一次取文件 Bh6lK}9
  
boolean bStop = false; //停止标志 v3]~*\!5  
File tmpFile; //文件下载的临时信息 buxyZV@1  
DataOutputStream output; //输出到文件的输出流 U,,r
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） sV`XJ9e|  
public SiteFileFetch(SiteInfoBean bean) throws IOException R-\"^BV#Z  
{ K(}<L-cv  
siteInfoBean = bean; ^I!gteU;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); /gE9 W  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 4cAx9bqA  
if(tmpFile.exists ()) z9^_5la#  
{ @C5%`{\  
bFirst = false; 'h{DjNSM  
read_nPos(); )H1chNI)  
} 9q"G g?  
else i$4lBy_2  
{ ~;nW+S$o  
nStartPos = new long[bean.getNSplitter()]; 9S)A6]  
nEndPos = new long[bean.getNSplitter()]; |(R[5q  
} f8L3+u  
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} IV$2`)[A&X  
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public void run() u2Qs}FX  
{ xqaw00,s  
//获得文件长度 lV2MRxI  
//分割文件 |}K7Q  
//实例FileSplitterFetch pXHeUBY.  
//启动FileSplitterFetch线程 %b`B.A  
//等待子线程返回 aV?r%'~Z  
try{ 9i#K{CkC|  
if(bFirst) fT_swhIO  
{ g3,F+  
nFileLength = getFileSize(); >eaK@
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if(nFileLength == -1) *gXm&/2*  
{ bLyG3~P;0  
System.err.println("File Length is not known!"); YiPp#0T[Gx  
} J*O$)K%Hx  
else if(nFileLength == -2) 1Du9N[2'P  
{ b1qli
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System.err.println("File is not access!"); jRIm_)  
} ph=[|P)  
else ;^:$O6J7T~  
{ hk1jxnQh  
for(int i=0;i<nStartPos.length;i++) Mt`XHXTp  
{ #n}n %  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); H[8P]"*z*i  
} oM#S
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for(int i=0;i<nEndPos.length-1;i++) ^7~w yAr  
{ .:#6dG\0z  
nEndPos = nStartPos[i+1]; YJ^TO\4WM  
} - dt<w;>W  
nEndPos[nEndPos.length-1] = nFileLength; jj 9eFB  
} "t"&6\  
} >zAI#N4  
H@WQO]PA  
LlG~aGhel  
//启动子线程 Bh,LJawE  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +bK.{1  
for(int i=0;i<nStartPos.length;i++) rfNt  
{ c F(]`49(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o(@F37r{?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), emI]'{_G  
nStartPos,nEndPos,i); L&nGjC+Lr  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); oxPb; %  
fileSplitterFetch.start(); 8W_X&X?Q  
} oFRb+H(E  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4x:Odt5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); {XNu4d9w(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]jzINaMav  
nEndPos = " + nFileLength); ico(4KSk  
// fileSplitterFetch[nPos.length-1].start(); 'HV}Tr  
[]M+(8Z_P  
t%AW0#TZ  
//等待子线程结束 }f6x>  
//int count = 0; W$B
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//是否结束while循环 rLcQG  
boolean breakWhile = false; _dEf@==  
*{)![pDYd  
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while(!bStop) 5aTyM_x  
{ T`=N^Ca1!`  
write_nPos(); g5to0  
Utility.sleep(500); EQ>bwEG  
breakWhile = true; vwzTrWA=  
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for(int i=0;i<nStartPos.length;i++) 6#5@d^a  
{ 0r=Lilu{q  
if(!fileSplitterFetch.bDownOver) ASaG }h  
{ h3xX26l  
breakWhile = false; N1(}3O  
break; SJ7>*Sa(u$  
} j&Ayk*  
} i4!n O
yk  
if(breakWhile) ^B?koU l^  
break; j>R7OGg'  
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//count++; Ye!=  
//if(count>4) K"b vUH  
// siteStop(); Hv0sl+  
} mXF pGo5 s  
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System.err.println("文件下载结束！"); [;5HI'px  
} n*iaNaU"'  
catch(Exception e){e.printStackTrace ();} M7,|+W/RK  
} +U%lWE%  
_zm<[0(  
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//获得文件长度 ,-DE;l^Q=  
public long getFileSize() JEBo!9  
{ #8|;Q`Or:  
int nFileLength = -1; 7X}_yMxc  
try{ 0#*\o1r\p  
URL url = new URL(siteInfoBean.getSSiteURL()); ^Z:x poz,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A7_*zR@  
httpConnection.setRequestProperty("User-Agent","NetFox"); n7<<}wcV  
/'VCJjzZ
 
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int responseCode=httpConnection.getResponseCode(); ?QVD)JI*k  
if(responseCode>=400) F/EHU?_EI  
{ 9CBB,  
processErrorCode(responseCode); _9 Gy`  
return -2; //-2 represent access is error 4?yc/F=kI  
} ={L:q8v)  
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String sHeader; (vj2XiO^+  
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p Y>yJ)  
for(int i=1;;i++) (J^ Tss  
{ ^jmnE.8R  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); MzG(+B  
//Utility.log(in.readLine()); BxZop.zwE(  
sHeader=httpConnection.getHeaderFieldKey(i); |g'sRTKJ  
if(sHeader!=null) TyBNRnkt  
{ Z(}x7jzW  
if(sHeader.equals("Content-Length")) Le3S;SY&  
{ @$nI\n?*  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9C4l@jrF  
break; %r
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} nO|S+S_9  
} `jZX(H  
else G8;S`-D1a,  
break; lMm-K%(2  
} )$]+R
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} %~W}262  
catch(IOException e){e.printStackTrace ();} Bw#ubQJ8}  
catch(Exception e){e.printStackTrace ();} I Mv^ 9T:  
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Utility.log(nFileLength); U|Jo[4A  
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{!/y@/NK2  
return nFileLength; V.-?aXQ*  
} <m6Xh^Ko;  
~<Lf@yu-{  
?\O+#U%W  
//保存下载信息（文件指针位置） 9=kTTFs  
private void write_nPos() bL&]3n9Rwu  
{ FSQ&J|O  
try{ 2?r8>#_*  
output = new DataOutputStream(new FileOutputStream(tmpFile)); kCwTv:)  
output.writeInt(nStartPos.length); 6>L.)V  
for(int i=0;i<nStartPos.length;i++) z1FbW&V  
{ _5K_YhT  
// output.writeLong(nPos); 1
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output.writeLong(fileSplitterFetch.nStartPos); |ber
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output.writeLong(fileSplitterFetch.nEndPos); ~r!5d@f.6  
} _eQ
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output.close(); V-cuG.  
} @\DD|o67  
catch(IOException e){e.printStackTrace ();} J
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catch(Exception e){e.printStackTrace ();} YT5>pM-%  
} *QG3Jz
 
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//读取保存的下载信息（文件指针位置） 1:Yt2]  
private void read_nPos() N#u8{\|8]  
{ da2[   
try{ pq[mM!;#v  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =_'cG:=)  
int nCount = input.readInt(); ,OKM\N,  
nStartPos = new long[nCount]; Jrk^J6aa  
nEndPos = new long[nCount]; YSV,q@I&1  
for(int i=0;i<nStartPos.length;i++) }x.)gW  
{ |\a:]SlH  
nStartPos = input.readLong(); KCk?)Qv  
nEndPos = input.readLong(); O$Vm#|$sq  
} x}.d`=  
input.close();
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} cY2-T#rL  
catch(IOException e){e.printStackTrace ();} ,z1!~gIal  
catch(Exception e){e.printStackTrace ();} 5b#6 Y
 
} X[Ek'=}  
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private void processErrorCode(int nErrorCode) b.4Xn0-M  
{ H\I!J@6g  
System.err.println("Error Code : " + nErrorCode); <8)s  
} F36ViN\b  
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//停止文件下载 [S]!+YBK  
public void siteStop() d=Do@) m|  
{ cIr1"5POXK  
bStop = true; wz+5 8(  
for(int i=0;i<nStartPos.length;i++) d_
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fileSplitterFetch.splitterStop(); t;!]z-Y>  
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} [tqO}D  
} }6J7<g  
//负责部分文件的抓取 <s8? Z1  
**FileSplitterFetch.java ^QAiySR`0  
*/ fhV0S>*<  
package NetFox; z8[H:W#G  
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import java.io.*; ,k~j6Z  
import java.net.*; ?Hi}nsw  
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public class FileSplitterFetch extends Thread { Mi}I0yhVm  
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String sURL; //File URL :,kU#eZ$-  
long nStartPos; //File Snippet Start Position i u1KRuaF[  
long nEndPos; //File Snippet End Position 8PBU~mr  
int nThreadID; //Thread's ID
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boolean bDownOver = false; //Downing is over kT^*>=1  
boolean bStop = false; //Stop identical wn+j39y?ZY  
FileAccessI fileAccessI = null; //File Access interface W7L+8LU;  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /2e%s:")h  
{ PW%1xHLfk  
this.sURL = sURL; 7qg<[  
this.nStartPos = nStart; >?5xDbRj  
this.nEndPos = nEnd; a@#Q:O)4  
nThreadID = id; _BV`,`8}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Wp5]Uk  
} aDL)|>"Q  
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public void run() $n= O  
{ yo'9x s  
while(nStartPos < nEndPos && !bStop) M8';%=@  
{ !4R>O6k  
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try{ NZLXN  
URL url = new URL(sURL); Ly9Q}dL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3Y z]8`C  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5W+{U8\  
String sProperty = "bytes="+nStartPos+"-"; +UxI{,L  
httpConnection.setRequestProperty("RANGE",sProperty); {A|bBg1!  
Utility.log(sProperty); =fl%8"%N&  
SLkuT`*  
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InputStream input = httpConnection.getInputStream(); .H8mRvd?  
//logResponseHead(httpConnection); %}C9
  
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byte[] b = new byte[1024]; Xv0F:1  
int nRead;
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while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +W9]ED  
{ %3M95UZ2  
nStartPos += fileAccessI.write(b,0,nRead); TPHYz>D]  
//if(nThreadID == 1) |olNA*4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0p-#f|ET  
} F
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Utility.log("Thread " + nThreadID + " is over!"); -kl;!:'.3  
bDownOver = true; 14H'!$  
//nPos = fileAccessI.write (b,0,nRead); nbGoJC:U  
} 6xHi\L  
catch(Exception e){e.printStackTrace ();} :zlpfm2  
} 6lsL^]7  
} _gKu8$o=-  
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//打印回应的头信息 f=o4I2Y[  
public void logResponseHead(HttpURLConnection con) <Nex8fiJ9  
{ zmI5"K"
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for(int i=1;;i++) XA1f' Kk  
{ JA`H@qE  
String header=con.getHeaderFieldKey(i); f&ytK  
if(header!=null) 9? 2  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); lUv=7" [  
Utility.log(header+" : "+con.getHeaderField(header)); 1}!L][(  
else P-'_}*wxi  
break; "cMNdR1^,y  
} /7gi/uh~-(  
} ?Ko|dmX  
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public void splitterStop() Vclr2]eV4O  
{ EMlIxpCn:  
bStop = true; "jR]MZ  
} HzvlF0f  
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} _A 2Lv]vfV  
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/* +8AvTSgX%  
**FileAccess.java *Y%Jl o  
*//文件访问(定位，写) )iU^&@[S  
package NetFox; FXahZW~Ol  
import java.io.*; Uoji@  
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public class FileAccessI implements Serializable{ A59gIp*>  
Oz{%k#X-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Qz+sT6js-  
RandomAccessFile oSavedFile; r`6:Q&&  
long nPos; h^oH^moq<  
ffE#^|  
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public FileAccessI() throws IOException .9h)bf+  
{ *Qkc[XHqy  
this("",0); S~)w\(r  
} x<ax9{  
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public FileAccessI(String sName,long nPos) throws IOException |~K(F<;j  
{ oM,- VUr  
oSavedFile = new RandomAccessFile(sName,"rw"); 6|!NLwa  
this.nPos = nPos; {38\vX,I(w  
oSavedFile.seek(nPos); Z\? E3j  
} CzVmNy)kl  
KX3KM!*  
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public synchronized int write(byte[] b,int nStart,int nLen) $`ztiVu3  
{ ?6P.b6m}0  
int n = -1; *(QH{!-$s  
try{ a1c1k}  
oSavedFile.write(b,nStart,nLen); 8TWTbQ  
n = nLen; CQ^3v09N;~  
} ^jD1vUL 2:  
catch(IOException e) v`DI<Lt  
{ sx 9uV  
e.printStackTrace (); A:# k  
} DBsDkkB{  
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return n; vl:J40Kfn  
} s8<gK.atl  
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} 3[IJhR[  
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/* U \oy8FZ  
**SiteInfoBean.java kV&9`c+  
*/ aeP[+I9  
package NetFox; cpZc9;@IC  
S%mfs!E>  
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public class SiteInfoBean { jQh^WmN  
{Wv%zA*8  
>v+jh(^  
private String sSiteURL; //Site's URL Y`G
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private String sFilePath; //Saved File's Path d=3'?l`  
private String sFileName; //Saved File's Name _yH`t[  
private int nSplitter; //Count of Splited Downloading File }-DE`c  
izZ=d5+K  
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public SiteInfoBean() 4Ysb5m
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{//nSplitter的缺省值为5 3x@<Z68S  
//default value of nSplitter is 5 )9v`f9X){  
this("","","",5); `BY&>WY[  
} uQqWew8l+  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7 sFz?`-  
{ y$W
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sSiteURL= sURL; V@vU"  
sFilePath = sPath; )3A{GZj#6  
sFileName = sName; BiwieF4x  
this.nSplitter = nSpiltter; !mJo'K  
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} ,h]o>  
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public String getSSiteURL() ?> Dtw#}  
{ GqKsK r2%  
return sSiteURL; zaimGMJ ,  
} TQ@d~GR  
w#y0atsg'  
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public void setSSiteURL(String value) 39i
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{ ^jE8+h  
sSiteURL = value; W"q@Qa`Bm  
} *OjKcs  
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IE2"rQT  
public String getSFilePath()  .)tSg  
{ XMIbUbUk-  
return sFilePath; ~B
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} XGrue6ya  
23\RJpKb  
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public void setSFilePath(String value) zYER  
{ <Zb/  
sFilePath = value; H}}$V7]^),  
} *e>]~Z,  
7[#yu2  
A^\.Z4=d"  
public String getSFileName() `)iY}Iu  
{ &[Xu!LP  
return sFileName; fV>CZ^=G  
} k?B[>aQn.0  
)!bUR\  
|SZo' 6  
public void setSFileName(String value) tRb]7 z  
{ 1{x.xi"A/  
sFileName = value; SLL3v,P(7  
} /1UOT\8U
 
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public int getNSplitter() d*8 $>GA  
{ v X~RP *  
return nSplitter; $ ,Ck70_  
}  mEG6  
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public void setNSplitter(int nCount) gmKGy@]
 
{ =WbOwI)u  
nSplitter = nCount; {P%9  
} yOU(2"8p  
} 2jJmE&)7,  
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'NjzgZ~]P  
/* 7,qYV}  
**Utility.java :$;Fhf<5  
*/ a]17qMl  
package NetFox; 7w:ef0S  
.~A*=  
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public class Utility { QfM zF  
OVzt\V*+%W  
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public Utility() Pt:e!qX)  
{ M-L2w"  
LsEXM-  
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} \J..*,'  
9_s6l  
//线程睡眠 ='ZRfb&  
public static void sleep(int nSecond) C (n+SY^  
{ J?@DGp+t  
try{ O4\Z!R60g  
Thread.sleep(nSecond); U@ ?LP  
} ;h6v@)#GX  
catch(Exception e) {^
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{ z?/1Kj}xG  
e.printStackTrace (); omO S=d!o  
} FuG4F  
} .;y#  
}jt?|dl1  
//日志  Amr[wx  
public static void log(String sMsg) T{wpJ"F5<]  
{ n~"$^Vr  
System.err.println(sMsg); <?-
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} w{[=l6L m  
4%4avEa"w  
(fNUj4[  
public static void log(int sMsg) v 8T$ &-HJ  
{ '
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System.err.println(sMsg); #/"8F O%~p  
} fbyQjvURnC  
} KoE8Mp  
T{V/+RM  
8`4<R6]LKB  
/* M` q?Fk  
**TestMethod.java E J$36  
*/ {FRAv(,\  
package NetFox; 2"|
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p.ANVA@:  
!CXt*/~  
public class TestMethod { gmIqT f  
*n]7  
\k;`}3uO  
public TestMethod() s]mo$ _na  
{ ///xx/weblogic60b2_win.exe R>DaOH2K*  
try{ (8v7|Pe8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ;^*Unyt[4]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4&
8Gr0C  
SiteFileFetch fileFetch = new SiteFileFetch(bean); P\8@g U!uk  
fileFetch.start(); FX9F"42@  
} SH*C
"  
catch(Exception e){e.printStackTrace ();} :[ k4Z]t8  
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`cPywn@uGZ  
} REZJ}%}/  
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public static void main(String[] args) [ W2fd\4  
{ 91Uj}n%  
new TestMethod(); iX0iRC6f
 
} u6`=x$&  
} xs\!$*R  
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