http断点续传简单实现（java)

/* }l$M%Ps!a  
**SiteFileFetch.java 9\3%5B7  
*/ ^y'xcq  
package NetFox; q)gZo[]~  
import java.io.*; W> .O"Ri  
import java.net.*; idnn%iO  
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public class SiteFileFetch extends Thread { ONJW*!(  
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}`6-^lj  
SiteInfoBean siteInfoBean = null; //文件信息Bean VOwt2&mZ  
long[] nStartPos; //开始位置 ?2[=llS4  
long[] nEndPos; //结束位置 fOiLb.BW  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 k/AcXU%O+  
long nFileLength; //文件长度 l2GMVAca  
boolean bFirst = true; //是否第一次取文件 ]Vhhx`0  
boolean bStop = false; //停止标志 +JZ<9,4  
File tmpFile; //文件下载的临时信息 G?\o_)IJ  
DataOutputStream output; //输出到文件的输出流 ;d G.oUk=  
$>v^%E;Y4  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） q_>DX,A  
public SiteFileFetch(SiteInfoBean bean) throws IOException <y'B !d#  
{ jjBcoQU$o  
siteInfoBean = bean; gXI_S9z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2g-'.w  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Y?%MPaN:  
if(tmpFile.exists ()) RBr  
{ @dX0gHU[c  
bFirst = false; z/ T|  
read_nPos(); _tL+39 u  
} S;NC
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else WhE5u&`  
{ w
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nStartPos = new long[bean.getNSplitter()]; 9pE)S^P  
nEndPos = new long[bean.getNSplitter()]; C yC<{D+  
} ^q"p8   
[ /*$?PXt  
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} o;FjpZ  
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public void run() 
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{ 5{#9b^  
//获得文件长度 &k\
7fvF  
//分割文件 z QoMHFL3  
//实例FileSplitterFetch Xfx(X4$9  
//启动FileSplitterFetch线程 }@@1N3nnxV  
//等待子线程返回 0LoA-c<Ay  
try{ M7yJ2u<Ty  
if(bFirst) l1jS2O(  
{ l,h
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nFileLength = getFileSize(); IOF~V)8k=  
if(nFileLength == -1) HG@!J>YaD  
{ uI%h$  
System.err.println("File Length is not known!"); 5<IUTso5h  
} ;Iw'TF   
else if(nFileLength == -2) !f)'+
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{ gtJ^8khME  
System.err.println("File is not access!"); ]gTaTY  
} )_+"  
else ZT8. r0  
{ y>2v 9;Qp  
for(int i=0;i<nStartPos.length;i++) %'\D_W&  
{ C,]Q/6'>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <WaiJy?  
} PZLWyp  
for(int i=0;i<nEndPos.length-1;i++) ] 5
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{ 'BAe>r_Pn  
nEndPos = nStartPos[i+1]; po=*%Zs*T  
} >~BU<#  
nEndPos[nEndPos.length-1] = nFileLength; (n"M)  
} ,~K_rNNZ  
} ?jw)%{iKYV  
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XF\`stEnb  
//启动子线程 <n }=zu  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ":]O3 D{r  
for(int i=0;i<nStartPos.length;i++) rorzxp{  
{ `<HY$PAe  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \Zoo9Wy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !"2OcDFx  
nStartPos,nEndPos,i); \nkqp   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &o4L;A#&  
fileSplitterFetch.start(); _I{&5V~z  
} b%$S6.  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H/)=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); A ,LAA$  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", C+5^[V  
nEndPos = " + nFileLength); dUb(C1h  
// fileSplitterFetch[nPos.length-1].start(); L8bq3Q'p  
"%f>/k;!h.  
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//等待子线程结束 k%In   
//int count = 0; xR#hU;E}  
//是否结束while循环 7{<F6F^P  
boolean breakWhile = false; mqsf#'ri  
Om}&`AP};  
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while(!bStop) Qs%f6rL  
{ B|,6m 3.  
write_nPos(); KL5rF,DME  
Utility.sleep(500); ~PlwPvWo  
breakWhile = true; 5I&^n0h|&  
[&{"1Z  
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for(int i=0;i<nStartPos.length;i++) 5V?1/  
{ ni%^w(J3Q  
if(!fileSplitterFetch.bDownOver) ;"Ot\:0  
{ @ K@~4!  
breakWhile = false; pY8+;w EI  
break; <mm}IdH  
} ~Dy0HVE   
} w-\fCp )  
if(breakWhile) nosEo?{  
break; m};
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[dzb{M6_  
//count++; ;m
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//if(count>4) }kOhwT8sI  
// siteStop(); klch!m=d  
} J25>t^  
(nE$};c<b2  
wfZ'T#1  
System.err.println("文件下载结束！"); Tu6he8Q-  
} p!Gf^  
catch(Exception e){e.printStackTrace ();} 6@I7UL >  
} ^k)f oD  
kW,
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//获得文件长度 <0kRky$  
public long getFileSize() (g4g-"rc  
{ +5({~2Lzvp  
int nFileLength = -1; {M%"z,GL7J  
try{ C*78Zw
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URL url = new URL(siteInfoBean.getSSiteURL()); d>AVUf<o~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8\a)}k~4  
httpConnection.setRequestProperty("User-Agent","NetFox"); -8pHjry'q  
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int responseCode=httpConnection.getResponseCode(); hCo&SRC/5  
if(responseCode>=400) JI*ikco-  
{ yNDyh  
processErrorCode(responseCode); lN1zfM  
return -2; //-2 represent access is error uY;/3?k&  
} /kJ*WA?J  
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\JyWKET::_  
String sHeader; 5#fLGXP  
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6*LU+U=`  
for(int i=1;;i++) qq?>ulu*W  
{ rmhCuY?f  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n!N;WL3k  
//Utility.log(in.readLine()); NFa ;  
sHeader=httpConnection.getHeaderFieldKey(i); *U8#'Uan  
if(sHeader!=null) +f7?L]wzic  
{ w{r->Phe  
if(sHeader.equals("Content-Length")) %(kq Hxc  
{ vEgJmHv;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); J}YI-t  
break; E""/dC:B  
} e6_.ID'3  
} 2;&13%@!  
else ! \gRXP}  
break; We4 FR4`  
} vc!S{4bN  
} YT3
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catch(IOException e){e.printStackTrace ();} .(hb8 rCM  
catch(Exception e){e.printStackTrace ();} &x3"Rq_  
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Utility.log(nFileLength); txgGL'  
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return nFileLength; [n}c}%  
} i;tA<-$-  
3jn@ [ m  
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//保存下载信息（文件指针位置） }(],*^'u-  
private void write_nPos() JZv]tJWq  
{ QO?ha'Sl  
try{ /9yiMmr5W  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {&;b0'!Tf  
output.writeInt(nStartPos.length); L.Lt9W2fi  
for(int i=0;i<nStartPos.length;i++) pts}?   
{ cp2fDn  
// output.writeLong(nPos); HdLkof2i  
output.writeLong(fileSplitterFetch.nStartPos); 7]^ }  
output.writeLong(fileSplitterFetch.nEndPos); U'lD|R,g  
} ,yqzk.  
output.close(); XnY}dsSO  
} ]_=HC5"  
catch(IOException e){e.printStackTrace ();} 8qc%{8  
catch(Exception e){e.printStackTrace ();} (o:CxhV  
} ^GAdl
}  
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p  
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//读取保存的下载信息（文件指针位置） ^&<*$Ai~  
private void read_nPos() s7 KKH w  
{ c%U$qao=c+  
try{ 6vjB;uS[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @uE=)mP@  
int nCount = input.readInt(); B~aOs>1 S]  
nStartPos = new long[nCount]; I[`2MKh  
nEndPos = new long[nCount]; !Q3Snu=  
for(int i=0;i<nStartPos.length;i++) %zD-gw>  
{ UxvsSHi  
nStartPos = input.readLong(); b(yO  
nEndPos = input.readLong(); KALg6DZe:  
} Gu}x+hG  
input.close(); nSow$6T_  
} ^kD?0Fm  
catch(IOException e){e.printStackTrace ();} ^VIUXa  
catch(Exception e){e.printStackTrace ();} bSR<d  
} &KvevPF  
4GfLS.Ip  
/SKr.S61e  
private void processErrorCode(int nErrorCode) W@C56fCa  
{ ]p*) PpIl  
System.err.println("Error Code : " + nErrorCode); :fYwFD( 9  
}
_Ry.Wth  
6uXW`/lvX  
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//停止文件下载 tZ
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public void siteStop() X@:fW @  
{ 9HE(*S  
bStop = true; G}-.
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for(int i=0;i<nStartPos.length;i++) 4d 3Znpf  
fileSplitterFetch.splitterStop(); }>w  
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XH *tChf<  
} D+)=bPMe  
} ._&lG3'  
//负责部分文件的抓取 <ut DZ#k  
**FileSplitterFetch.java 4ufLP DH  
*/ q-G|@6O  
package NetFox; (K6`nWk2  
@Y<tH,*  
=.X?LWKY  
import java.io.*; f>5RAg  
import java.net.*; ZQkw}3*n  
@."o:K  
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public class FileSplitterFetch extends Thread { BR^J y<^F'  
Vrj1$NL%  
iW}l[g8sw!  
String sURL; //File URL 9xQ8`7  
long nStartPos; //File Snippet Start Position 4LEE /  
long nEndPos; //File Snippet End Position NN 6KLbC(  
int nThreadID; //Thread's ID i f<<lq  
boolean bDownOver = false; //Downing is over ]X~g@O{>_  
boolean bStop = false; //Stop identical )h0E$*  
FileAccessI fileAccessI = null; //File Access interface LZ)m](+M  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0c61q Q6  
{ eM+;x\j
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this.sURL = sURL; -z0{\=@#m  
this.nStartPos = nStart; !NYM(6!(  
this.nEndPos = nEnd; gc@#O#K~h^  
nThreadID = id; ?GNF=#=M  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "x;k'{S  
} n+qVT4o  
&fSc{/  
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public void run() tt]V$V  
{ WQ}!]$<"y  
while(nStartPos < nEndPos && !bStop) = (gmd>N  
{ eAsX?iaH  
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try{ 8q [c  
URL url = new URL(sURL); egvy#2b@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }=hoATs  
httpConnection.setRequestProperty("User-Agent","NetFox"); X^D9)kel  
String sProperty = "bytes="+nStartPos+"-"; 2-V)>98  
httpConnection.setRequestProperty("RANGE",sProperty); ;hA7<loY  
Utility.log(sProperty); 7_40_kwJi  
2ly,l[p8  
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InputStream input = httpConnection.getInputStream(); T_x+sv=|X!  
//logResponseHead(httpConnection); @qPyrgy  
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N 2"3~  #  
byte[] b = new byte[1024]; _ML~c&9jv  
int nRead; |R;l5ZKvV  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^Y7/Ow  
{ em1cc,  
nStartPos += fileAccessI.write(b,0,nRead); !wd'::C  
//if(nThreadID == 1) T1QsW<*j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E ;!<Z4  
} *?bk?*?s  
=kb6xmB^t  
%R|"Afa=  
Utility.log("Thread " + nThreadID + " is over!"); e[QxFg0E  
bDownOver = true; )4~sQ^}  
//nPos = fileAccessI.write (b,0,nRead); :5S |x/  
} *1W,Mzg  
catch(Exception e){e.printStackTrace ();} tP`G]BCbt  
} QM ZUt  
} '}Wu3X  
+l
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{@V3?pG?p  
//打印回应的头信息 }xb_s  
public void logResponseHead(HttpURLConnection con) z,bX.*.-  
{ g. ?*F#2  
for(int i=1;;i++) TH>?Gi)"  
{ 7wQ+giu  
String header=con.getHeaderFieldKey(i); xegQR
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if(header!=null) t0bhXFaiE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); abo>_"9-  
Utility.log(header+" : "+con.getHeaderField(header)); ~`2&'8  
else u`Z0{d  
break; b0YiQjS6>  
} nuSN)}b<Q  
} Ug7`ez4vw  
`z}vONXpAX  
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public void splitterStop() j/H>0^  
{ c6,s+^^  
bStop = true; l Io9,K
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} F#1 Kk#t  
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5L-lpT8P  
} [0u.}c;(  
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v7;J%9=0D`  
/* ;%u_ ;,((  
**FileAccess.java Dxt),4%P  
*//文件访问(定位，写) 2(m85/Hr\;  
package NetFox; RCBf;$O  
import java.io.*; :8^M
5}  
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;&Bna#~B  
public class FileAccessI implements Serializable{ mRhd/|g*  
7fju  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 +@emX$cFV  
RandomAccessFile oSavedFile; ME$2P!o  
long nPos; yo\N[h7  
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7/H^<%;y  
public FileAccessI() throws IOException fJN*s  
{ C.J`8@a]?  
this("",0); Oj4v#GK]  
} 4\LZD{  
rv9B}%e  
#NvQmz?J?  
public FileAccessI(String sName,long nPos) throws IOException bTLMd$  
{ Jd5\&ma  
oSavedFile = new RandomAccessFile(sName,"rw"); k"xGA*B|  
this.nPos = nPos; {=UFk-$=  
oSavedFile.seek(nPos); fdlvn*H  
} D \N \BD  
3k#[(phk  
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public synchronized int write(byte[] b,int nStart,int nLen) z Yw;q3"  
{ U;xu/xDRi  
int n = -1; Y^52~[w~  
try{ q#P$'7"  
oSavedFile.write(b,nStart,nLen); v(DwU!  
n = nLen; 'X =p7 d|'  
} )~ 0}Et l  
catch(IOException e) o:2Q2+d  
{ D.'h?^kA  
e.printStackTrace (); JD6aiI!Su  
} C5P$&s\  
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return n; jY7=mAd  
} *YWk1Cwjo  
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} %.mEBI=hs  
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V=pMq?Nr  
/* TG}d3ZU !  
**SiteInfoBean.java %$@1FlqX;  
*/ .%=V">R  
package NetFox; F{<5aLaYti  
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i  
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public class SiteInfoBean { ~h
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[J^  
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private String sSiteURL; //Site's URL m9in1RI%  
private String sFilePath; //Saved File's Path +`@M*kd  
private String sFileName; //Saved File's Name j5Qo*p  
private int nSplitter; //Count of Splited Downloading File {
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^/HW$8wEi  
lbQQtpEKO  
public SiteInfoBean() >M]6uf  
{//nSplitter的缺省值为5 '+j<n[JLC  
//default value of nSplitter is 5 _AFQ>j  
this("","","",5); 62)d22  
} NzQ9Z1Mxy  
: [q0S@  
^$v3
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &(EHq  
{ j[I`\"  
sSiteURL= sURL; b_TS<,  
sFilePath = sPath; 98RKCc9h  
sFileName = sName; FmEc`N9\v  
this.nSplitter = nSpiltter; }bH
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3iRA$C-p  
} "13"`!m  
> _ <'D  
k|xtrW`qo;  
public String getSSiteURL() Y34/+Fi  
{ G O{.9_2  
return sSiteURL; *wuqa)q2  
} !*aPEf270  
Z\~GU*Y.e  
5;\gJf  
public void setSSiteURL(String value) #`(WUn0H?  
{ ]PWDE"  
sSiteURL = value; {ox2Tg?  
} M*sR3SZ  
O:'?n8rWL  
+vW)vS[  
public String getSFilePath() :w`3cwQ  
{ l.`u5D  
return sFilePath; .~>?*}  
} j~E",7Q'  
K
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}lP;
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public void setSFilePath(String value) ljC(L/I  
{ RBwO+J53y  
sFilePath = value; ]}Z4P-"t  
} ST5V!jz  
r@U3sO#N  
a,|?5j9,P  
public String getSFileName() ?m7:if+y  
{ ujFzJdp3k  
return sFileName; s&a1y~rv  
} fpWg R4__  
oR .cSGh  
b| M3`  
public void setSFileName(String value) J-xS:Ha'l  
{ cc}Key@D  
sFileName = value; 7a4o1;l  
} <IJu7t>  
(xl\J/  
d>0+A)6>  
public int getNSplitter() K4Sk+ v  
{ 6"/WZmOp  
return nSplitter; $P z`
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} ,CvG 20>  
<eN_1NTH_  
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public void setNSplitter(int nCount) j}1zdA  
{ mYxyWB  
nSplitter = nCount; dq\FBwfe  
} 6at1bQ$  
} bWWXc[O2&(  
vb Y3;+M>  
6e,xDr  
/* .IarkeCtb  
**Utility.java 7O5`v(<9n>  
*/ 5U`ZbG  
package NetFox; /./"x
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[AU II*:}  
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public class Utility { i;/xK
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^3VR-u<O  
public Utility() /ID3s`D)  
{ xu5ia|gYz7  
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} v+7kU=  
#:jb*d?  
//线程睡眠 {\H/y c|@  
public static void sleep(int nSecond) 54lu2gD'  
{ mw$r$C
{  
try{ aNcd` $0  
Thread.sleep(nSecond); S$TmZk=  
} M<O{O}t<  
catch(Exception e) Vd^g9  
{ E 99hlY~1:  
e.printStackTrace (); $YxBE`)d-  
} (*}yjUYLZ  
} S$)*&46g  
^G&3sF}  
//日志 ^d}gpin  
public static void log(String sMsg) }KUd7[
s  
{ GSclK|#tE  
System.err.println(sMsg); q6Rr
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} q<y#pL=k"*  
o[oM8o<  
m!<i0thJ  
public static void log(int sMsg) m>USD?i  
{ w(ln5q  
System.err.println(sMsg); <q*oV  
} dr)YzOvba  
} 6+r$t#  
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_Zk{!  
/*
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**TestMethod.java )?+$x[f!*  
*/ 1b=lpw1}  
package NetFox; oSiMpQu08  
|4$M]Mf0  
E_Z{6&r  
public class TestMethod { C~fjWz' V  
O~j> ?  
ah
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public TestMethod() J
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{ ///xx/weblogic60b2_win.exe sn7AR88M;  
try{ |*Z$E$k:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Lg8nj< TF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *I}`dC[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 'iLpE7  
fileFetch.start(); 4tL<q_  
} ~wg:!VWA)  
catch(Exception e){e.printStackTrace ();} X%yO5c\l2  
]7-&V-Ct*  
F, U*
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} SGb;!T*  
mF` B#  
n]8<DX99Q0  
public static void main(String[] args) %X#zj"  
{ 2,ECYie^  
new TestMethod(); \RNg|G  
} /Mb"V5S(W  
} %%(R@kh9  
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