http断点续传简单实现（java)

/* *ZF:LOnU  
**SiteFileFetch.java u|\K kk  
*/ 1DM$FG_Z-  
package NetFox; 5 OF*PBZ  
import java.io.*; mbZg2TTy  
import java.net.*; u %&4[zb  
lK #~lC  
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public class SiteFileFetch extends Thread { +yI
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SiteInfoBean siteInfoBean = null; //文件信息Bean p0j-$*F  
long[] nStartPos; //开始位置 ]=m0@JTbG  
long[] nEndPos; //结束位置 *wK7qS~VB2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 LX iis)1  
long nFileLength; //文件长度 ?1lx8+  
boolean bFirst = true; //是否第一次取文件 gBXJ/BW$y  
boolean bStop = false; //停止标志 cUM#|K#6  
File tmpFile; //文件下载的临时信息 Gm'Ch}E  
DataOutputStream output; //输出到文件的输出流 R=s^bYdoy  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） wfc+E9E  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,v*<yz/  
{ bL18G(5  
siteInfoBean = bean; -xc'P,`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X.<2]V7!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); zd#/zUPI  
if(tmpFile.exists ()) b. oA}XP  
{ p4I6oS`/.  
bFirst = false; [:C!g#o  
read_nPos(); d
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} +G>
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else O8S"B6?$~'  
{ n{r
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nStartPos = new long[bean.getNSplitter()]; y5bELWA  
nEndPos = new long[bean.getNSplitter()]; CF+:9PG  
}  p(Bn!  
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} 
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public void run() )t$|'c}  
{ JK9}Kb};  
//获得文件长度 )0NE_AZ?  
//分割文件 3Q"4-pd  
//实例FileSplitterFetch Oy/+uw^  
//启动FileSplitterFetch线程 2KC~;5  
//等待子线程返回 ^atB
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try{ )q+9_KUq  
if(bFirst) x9!vtrM\Zr  
{ 
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nFileLength = getFileSize(); (j;6}@  
if(nFileLength == -1) _ s[v:c  
{ >HXmpu.O  
System.err.println("File Length is not known!"); H|iY<7@  
} *FT )`  
else if(nFileLength == -2) ?=h{`Ci^ $  
{ )gR !G]Y  
System.err.println("File is not access!"); X%b.]A  
} p KF>_\   
else s$ 2@|;  
{ 4X &\/X  
for(int i=0;i<nStartPos.length;i++) s~(iB{-  
{ V5{^R+_)Ya  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); L)o7~M  
} f}cz_"o4  
for(int i=0;i<nEndPos.length-1;i++) &m6x*i-5\f  
{ /WJ*ro]Hd$  
nEndPos = nStartPos[i+1]; ?][2J
 
} $3Ct@}=n  
nEndPos[nEndPos.length-1] = nFileLength; Vnv9<=R  
} %?3\gFvBo  
} ]'F{uDm[  
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+89s+4Jn  
//启动子线程 XKU+'Tz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; < g<Lf[n$  
for(int i=0;i<nStartPos.length;i++) })R8VJ&C/  
{ t1)b26;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0NB6S&lI^k  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), XACbDKyS  
nStartPos,nEndPos,i); =x4:jas  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Gw$sL&1m\  
fileSplitterFetch.start(); Xh
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} :A,V<Es}I"  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _|S>,D'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); -k p~pe*T  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lMX 2O2 o  
nEndPos = " + nFileLength); ~
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// fileSplitterFetch[nPos.length-1].start(); Ok+zUA[Wu  
6Z
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->oQ,ezB  
//等待子线程结束 ^IxT.g  
//int count = 0; -}m#uUqI  
//是否结束while循环 s7CoUd2  
boolean breakWhile = false; 0}YR=  
%:n1S]Vr  
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while(!bStop) _M+'30  
{ nu] k<^I5|  
write_nPos(); ~ySmN}3~'  
Utility.sleep(500);
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breakWhile = true; ~y}M GUEC  
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22
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for(int i=0;i<nStartPos.length;i++) sQ/7Mc  
{ JbG\Ywi0]  
if(!fileSplitterFetch.bDownOver) >wjWX{&?  
{ h'<}
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breakWhile = false; #D3e\(  
break; fMr6ZmB  
} R0;c'W)  
} br}.s@~  
if(breakWhile) J"8bRp=/|  
break; =y8HOT}8  
,~FyC_%*  
UM7Ft"  
//count++; Tk9*@
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//if(count>4) ](NSpU|*  
// siteStop(); |H5){2V>K  
} 6g!#"=ls;  
|v8>22y  
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)  
System.err.println("文件下载结束！"); &-+qB >SK>  
} }1w[G;$  
catch(Exception e){e.printStackTrace ();} 2GcQh]ohc  
} K;G1cFFyG  
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;u,%an<(  
//获得文件长度 ?]f+)tCMs  
public long getFileSize() 5Ga
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{ (`4^|_gw  
int nFileLength = -1; TQ" [2cY  
try{ whoz^n3NE  
URL url = new URL(siteInfoBean.getSSiteURL()); |Wj)kr !|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Q<zL;AJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); *(L4
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int responseCode=httpConnection.getResponseCode(); *D F5sY  
if(responseCode>=400) HGB96,o f9  
{ Jd&Qi)1  
processErrorCode(responseCode); K8{j oh  
return -2; //-2 represent access is error QY-P!JD  
} W<yh{u&,  
J'Yj_  
z]Z>+|  
String sHeader; /J3e[?78u  
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for(int i=1;;i++) tHXt*tzq  
{ %fh ,e5(LT  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }@4m@_gR?  
//Utility.log(in.readLine());  nq8mzI  
sHeader=httpConnection.getHeaderFieldKey(i); (p68Qe%OuG  
if(sHeader!=null) i5|A\Wv"  
{ R8Lp8!F'  
if(sHeader.equals("Content-Length")) s}`ydwSg8  
{ ;QW6Tgt11  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); DuZ51[3_L  
break; +=|Q'V  
} nBaY|  
} 9HRYk13ae  
else ai`fP{WlX  
break; ??aOr*%  
} Bb]

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} =!9+f  
catch(IOException e){e.printStackTrace ();} QSAz:Yvf|  
catch(Exception e){e.printStackTrace ();} Bg"b,&/^u  
,/m<=`*N|  
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Utility.log(nFileLength); '+Gt+Gq+  
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return nFileLength; $9+}$lpPd  
} I^[R]Js  
\QBODJ1  
r{#od 7;  
//保存下载信息（文件指针位置） ' ,a'r.HJH  
private void write_nPos() g>_6O[;t%  
{ rV"<1y:g  
try{ hh{4r} |  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (JocnM|U  
output.writeInt(nStartPos.length); 9vmH$  
for(int i=0;i<nStartPos.length;i++) @mNf(&  
{ )j4]Y dJ  
// output.writeLong(nPos); z62
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output.writeLong(fileSplitterFetch.nStartPos); 1G=1FGvP  
output.writeLong(fileSplitterFetch.nEndPos); f/&Dy'OV7  
} )T(xQ2&r4  
output.close(); 7cK#fh"hvg  
} -F/"W  
catch(IOException e){e.printStackTrace ();} >+7+ gSD#:  
catch(Exception e){e.printStackTrace ();} AVOzx00U  
} u<]-%ha$  
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&AU%3b  
//读取保存的下载信息（文件指针位置） .D-}2<z  
private void read_nPos() z/.x
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{ pez[qs  
try{ TixHEhw
 
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?#<Fxme  
int nCount = input.readInt(); x9a*^l  
nStartPos = new long[nCount]; ^IjKT  
nEndPos = new long[nCount]; ]sd|u[:k  
for(int i=0;i<nStartPos.length;i++) yXh=~:1~  
{ D}SRr,4v  
nStartPos = input.readLong(); V.XHjHT  
nEndPos = input.readLong(); rG:IS=  
} Q|@!zMy  
input.close(); IU{~{(
p"  
} 2Y(Phw2%  
catch(IOException e){e.printStackTrace ();} o*_[3{FU  
catch(Exception e){e.printStackTrace ();} `pn]jpW9  
} 3=o3VGZP  
6;dQ#wmg  
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private void processErrorCode(int nErrorCode) H~i+:X=I  
{ UAFl+d!  
System.err.println("Error Code : " + nErrorCode); yc8iT`
 
} RgHPYf{  
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//停止文件下载 %Nwap~=H;  
public void siteStop() (x@|6Sb  
{ p(8
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bStop = true; B# |w}hj  
for(int i=0;i<nStartPos.length;i++) *TfXMN?w  
fileSplitterFetch.splitterStop(); ZF_*h`B  
!>TVDN>  
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} :XxsDD  
} dGt;t5AnV  
//负责部分文件的抓取 8)s}>:}  
**FileSplitterFetch.java 0UB)FK,9  
*/ -GLI$_lLF  
package NetFox; ;+'x_'a  
#K.OJJaG  
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import java.io.*; kO{A]LnAH  
import java.net.*; OBqaf )W  
zlco?Rt  
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public class FileSplitterFetch extends Thread { LX[<Wh_X(  
@d:TAwOI'  
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String sURL; //File URL 9_)*b  
long nStartPos; //File Snippet Start Position hm*1w6 =  
long nEndPos; //File Snippet End Position 1v)ur\>R  
int nThreadID; //Thread's ID vnwS&;-k~  
boolean bDownOver = false; //Downing is over 15U]/?jv8  
boolean bStop = false; //Stop identical a'u:1C^\  
FileAccessI fileAccessI = null; //File Access interface lK;|ciq"c7  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _^]2??V  
{ B*!{LjXV  
this.sURL = sURL; i%w[v_j  
this.nStartPos = nStart; }c|)i,bL  
this.nEndPos = nEnd; M6
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nThreadID = id; M:K5r7Q!yv  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 04g=bJ  
} *;@V5[^3I?  
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public void run() NrA?^F  
{ xc{$=>'G  
while(nStartPos < nEndPos && !bStop) TK^9!3  
{ tk=~b}8  
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try{ U0>Uqk",  
URL url = new URL(sURL); C]H'z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .rp
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httpConnection.setRequestProperty("User-Agent","NetFox"); T6_LiB@  
String sProperty = "bytes="+nStartPos+"-"; vU|=" #  
httpConnection.setRequestProperty("RANGE",sProperty); (Klvctoy  
Utility.log(sProperty); <uq#smY  
)2
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InputStream input = httpConnection.getInputStream(); /DLgE7iU%  
//logResponseHead(httpConnection); EhJpJb[Z  
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~d5f]6#`  
byte[] b = new byte[1024]; o m9zb&{tu  
int nRead; 3jx5Lou)&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1:{BC2P  
{ 4l)Q  
nStartPos += fileAccessI.write(b,0,nRead); |Iq#Q3w  
//if(nThreadID == 1) eD<Kk 4){  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Km/#\$|}  
} )Pj8{.t4  
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Utility.log("Thread " + nThreadID + " is over!"); WBOe
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bDownOver = true; m~$S]Wf  
//nPos = fileAccessI.write (b,0,nRead); %v)m&VUi%  
} 78o>UWA:  
catch(Exception e){e.printStackTrace ();} q,ur[ &<  
} %p wpRD@  
} #}y(D{zc  
Gh.@l\|tf  
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//打印回应的头信息 fwWE`BB  
public void logResponseHead(HttpURLConnection con) >S]_{pb  
{ H6fR6Kr4j  
for(int i=1;;i++) 85fv])\y  
{ '5V#sq;Z  
String header=con.getHeaderFieldKey(i); X.YMb .\<  
if(header!=null) o>G^)aRa  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); a d,0*(</  
Utility.log(header+" : "+con.getHeaderField(header)); 8r|5l~`8  
else Td|x~mZv:  
break; vbn'CY]QU  
} RMrrLT  
} B^{87YR  
3J{hG(5  
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public void splitterStop() 9[L@*7A`m  
{ $IdY(f:.:5  
bStop = true; xQKD1#y  
} BAQ;.N4  
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} #c2InwZV  
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Xy;!Q`h(  
/* ^mNPP:%iN  
**FileAccess.java T-'B-g  
*//文件访问(定位，写) .W9/*cZV0  
package NetFox; l}Fa-9_'  
import java.io.*; Q302!N  
lvyD#|P  
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public class FileAccessI implements Serializable{ N]p|c3D  
k*;2QED  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s\-^vj3  
RandomAccessFile oSavedFile; /_,} o7@t~  
long nPos; -6()$cl}0  
.W>8bg'u9  
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public FileAccessI() throws IOException }PR^Dj.  
{ CwV1~@{-  
this("",0); kZlRS^6  
} )~](qLSl  
yk5T"#'+  
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public FileAccessI(String sName,long nPos) throws IOException $=97M.E  
{ FZ)Y<r8|s  
oSavedFile = new RandomAccessFile(sName,"rw"); Oc]&1>M  
this.nPos = nPos; FC= %_y  
oSavedFile.seek(nPos); `P`nqn  
} p,?8s%  
lB\"*K;  
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public synchronized int write(byte[] b,int nStart,int nLen) jH*+\:UP-  
{ $Xlyc.8YId  
int n = -1; 5T[9|zJs  
try{ ,x+_/kqx  
oSavedFile.write(b,nStart,nLen); Lp \%-s#5s  
n = nLen; %qzpt{'?<  
} ;z9(  
catch(IOException e) dk
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{ !Xwp;P=  
e.printStackTrace (); zX
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} ;+-$=l3[a  
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return n; mu1oD;lQ  
} uP/WRQ{rW>  
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} ~'WvIA (  
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/* 4\q7.X+^  
**SiteInfoBean.java AWLKve_  
*/ %r5&CUE5?  
package NetFox; /Q"nQSG  
M* W=v  
p[e|N;W8A  
public class SiteInfoBean { +w/Ax[K  
Ep}KIBBO  
RB_7S!qC5  
private String sSiteURL; //Site's URL gKg2Ntx
j  
private String sFilePath; //Saved File's Path 8w|j Z@  
private String sFileName; //Saved File's Name G'( %8\  
private int nSplitter; //Count of Splited Downloading File .2hQ!)+  
vi6EI wZG  
}>xgzhdT  
public SiteInfoBean() ~(B\X?v  
{//nSplitter的缺省值为5 _Z6/r^c  
//default value of nSplitter is 5 r0kA47  
this("","","",5); J+&AtGq]u  
} J p .wg  
CF^7 {g(y_  
-8tWc]c |4  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) zQ {g~x  
{ GI$t8{M  
sSiteURL= sURL; ',0~\V  
sFilePath = sPath; vj
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sFileName = sName; Cc]s94  
this.nSplitter = nSpiltter; ~}4o=O(  
@yaBtZUp3  
+[r%y,
k  
} tGzYO/Zp  
d{0w4_x  
%H-[u}s  
public String getSSiteURL() *|Re,cY  
{ ~0fT*lp  
return sSiteURL; UhY )rezh  
} d\, 4Wet;#  
UL[4sv6\9  
 | qHWM  
public void setSSiteURL(String value) $BE^'5G&4Y  
{ ~u8}s4  
sSiteURL = value; aQN`C{nY  
} #rV=!j||  
@DkPJla&  
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public String getSFilePath() %>i7A?L  
{ PZpwi?N  
return sFilePath; +M@G 8l  
} Vw9^otJu  
]Vl5v5_  
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public void setSFilePath(String value) /^uvY  
{ $2>tfKhtA  
sFilePath = value; .2 UUU\/5  
} }#<Sq57n  
uh#PZ xnP  
(L|SE4  
public String getSFileName() 2t
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{ 'cw0Fp
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return sFileName; ~uC4>+dk  
} r=L9x/r  
K^{`8E&A  
![abDT5![  
public void setSFileName(String value)  Kz3u  
{ 1V+1i)+  
sFileName = value; 7R))(-  
} .2xypL8(  
a2=wJhk  
CM5A-R90  
public int getNSplitter() d*A>P  
{ U"m!f*a  
return nSplitter; 0E\R\KO$>  
} K:y q^T7  
4#2iL+   
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public void setNSplitter(int nCount) ^Y'J0v2  
{ q`$QroZT"  
nSplitter = nCount; bq(*r:`"  
} X'?v8\mPK  
} P< WD_W  
HENCQ_Wra  

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/* Plq[Ml9  
**Utility.java hq,;H40%/  
*/ ,s)~Y p?<  
package NetFox; 2OT6*+D  
!@YYi[Gk  
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public class Utility { vQ_B2#U:  
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8V|-BP5^  
public Utility() bR8)s{p6  
{ FBY~Z$o0.  
aS
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} -+PPz?0  
^@19cU?q  
//线程睡眠 A.h?#%TLL  
public static void sleep(int nSecond) F 5JgR-P  
{ xK y<o  
try{ y]CJOC)/K  
Thread.sleep(nSecond); u?J(l)gd  
} '~2v/[<`}  
catch(Exception e) _x'StD  
{ cq=R  
e.printStackTrace (); (qG$u&  
} (i?^g &  
} Ucy9fM  
\c\
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//日志 tV,zz;* Oe  
public static void log(String sMsg) qB:`tHy  
{ F
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System.err.println(sMsg); <5#e.w  
} :_H88/?RR  
*&P
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Bf}_ Jw-=  
public static void log(int sMsg) A+l"  
{ s-ou;S3s  
System.err.println(sMsg); Aa Ma9hvT!  
} 0x &^{P~  
} 'oEmbk8Hg  
ie,{C  
;'Q{ ywr  
/* ;i:7E#@  
**TestMethod.java ' #mC4\<W8  
*/ lt4UNJ3w  
package NetFox; BxqCV%9o  
xV6j6k  
hf-S6PEsM  
public class TestMethod { Ii8jY_  
P}I*SV0  
[KKo
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public TestMethod() `Qhh{  
{ ///xx/weblogic60b2_win.exe @hvq,[  
try{ w&gHmi  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); hJ@nW5CI  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?`XKaD! f  
SiteFileFetch fileFetch = new SiteFileFetch(bean); &Xav$6+Z1J  
fileFetch.start(); Z4!3I@yZ  
} RW)C<g  
catch(Exception e){e.printStackTrace ();} 4jW{IGW  
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f,#xicSB*  
} x'qgpG}?]  
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9T1G/0k-  
public static void main(String[] args) tF
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{ KOQTvJ_#  
new TestMethod(); Vh8uE  
} qrkT7f  
} uz#9w\="  
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