http断点续传简单实现（java)

/* *b)b#p  
**SiteFileFetch.java y:A0!75  
*/ R{
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package NetFox; 2YN`:"  
import java.io.*; Y
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import java.net.*; s{k\1P(G}  
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public class SiteFileFetch extends Thread { t~M<j|]k  
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SiteInfoBean siteInfoBean = null; //文件信息Bean o(``7A@7a  
long[] nStartPos; //开始位置 epbp9[`  
long[] nEndPos; //结束位置 xI<dBg|]+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 `e9uSF:9C  
long nFileLength; //文件长度 dI!/:x  
boolean bFirst = true; //是否第一次取文件 =CVT8(N*  
boolean bStop = false; //停止标志 +wUhB\F *  
File tmpFile; //文件下载的临时信息 -$)Et|  
DataOutputStream output; //输出到文件的输出流 "<2bjy  
-7O/ed+  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） o3yqG#dA  
public SiteFileFetch(SiteInfoBean bean) throws IOException "?{yVu~9  
{ 7:L~n(QpP  
siteInfoBean = bean; '&QT}B  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0X?fDz}jd  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .O#lab`:2  
if(tmpFile.exists ()) E)hinH  
{ 9-Qtj49  
bFirst = false; C%c `@="b  
read_nPos(); na3kHx@  
} WHZng QmY  
else SU'1#$69F  
{ "
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nStartPos = new long[bean.getNSplitter()]; x#0@$  
nEndPos = new long[bean.getNSplitter()]; $M`;."
 
} 02^(z6K'&?  
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} W>s'4C`  
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public void run() jN}7BbX  
{ +@uC:3jM  
//获得文件长度 {}o>nenx\  
//分割文件 p\_qHq\;j  
//实例FileSplitterFetch U9o*6`"o  
//启动FileSplitterFetch线程 =Xjuz:9D~  
//等待子线程返回 8Qz7uPq  
try{ d+2O^of:T  
if(bFirst) *@arn Eu  
{ M y"!j,Up  
nFileLength = getFileSize(); z){UuiUM+=  
if(nFileLength == -1) '}`hY1v  
{ SfobzX}~Jh  
System.err.println("File Length is not known!"); ?SOF n  
} wwcwYPeg  
else if(nFileLength == -2) 06@0r  
{ /^33 e+j  
System.err.println("File is not access!"); M}oj!xGB  
} 9;Pu9s[q2  
else ms\/=96F  
{ dezL{:Ya  
for(int i=0;i<nStartPos.length;i++) D ,ZNh1xt  
{ HA.NZkq.tV  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cevV<Wy+  
} Q
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for(int i=0;i<nEndPos.length-1;i++) DET!br'z5  
{
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nEndPos = nStartPos[i+1]; Go+xL/f  
} %M)oHX1p  
nEndPos[nEndPos.length-1] = nFileLength; 9Oo*8wvGG  
} fpK0MS]=b  
} Ul713Bjz  
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//启动子线程 9 /Ai(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; GE~(N N  
for(int i=0;i<nStartPos.length;i++) K?Xo3W%K  
{ ^z%o];  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), P$6f+{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), i3l #~  
nStartPos,nEndPos,i); &X]=Qpl  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @Uj_+c q  
fileSplitterFetch.start(); qtwT#z;Y  
} :&1=8^BY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), itC *Z6^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); kk/+Vx~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ss<_K>wk  
nEndPos = " + nFileLength); K*_{Rs0P  
// fileSplitterFetch[nPos.length-1].start(); fs3-rXoB  
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//等待子线程结束 !7kLFW  
//int count = 0; n<%=~1iY+  
//是否结束while循环 LA;V}%y?  
boolean breakWhile = false; .,ppGc|*  
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while(!bStop) vNK`Y|u@  
{ g]==!!^<D  
write_nPos(); (ifqwl62  
Utility.sleep(500); ){:q;E]^fB  
breakWhile = true; qr'x0r|<>  
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for(int i=0;i<nStartPos.length;i++) /Oq)3fU e  
{ `bZ2x
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if(!fileSplitterFetch.bDownOver) /jZaU`  
{ &Hlm{FHU  
breakWhile = false; q:2aPfo&  
break; e>?_)B4  
} B8cBQv  
} {?@t/.4[W3  
if(breakWhile) ;T5,T   
break; "}'8`k+d  
r 1l/) ;  
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//count++; -~vl+L  
//if(count>4) IFd )OZ5  
// siteStop(); fCt^FU  
} "<PoJPh  
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System.err.println("文件下载结束！"); IgPV#  
} 3d,-3U  
catch(Exception e){e.printStackTrace ();} #D|! .I)  
} 3bbp>7V!  
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//获得文件长度 ZdE>C  
public long getFileSize() e-[>( n/[  
{ _o@(wGeu#  
int nFileLength = -1; ]dPVtk  
try{ rao</jN.9  
URL url = new URL(siteInfoBean.getSSiteURL()); F[>7z3I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1fz*SIjG  
httpConnection.setRequestProperty("User-Agent","NetFox"); U}tl_5%)  
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int responseCode=httpConnection.getResponseCode(); >.DF"]XM  
if(responseCode>=400) B<|:K\MA  
{ OOEV-=  
processErrorCode(responseCode); qn2o[x  
return -2; //-2 represent access is error !MZ+-dpK  
} ZWf-X  
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String sHeader; O0@w(L-  
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for(int i=1;;i++) GE%2/z p  
{ RY9+ 9i  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); xj0cgK|!  
//Utility.log(in.readLine()); ,/i_QgP  
sHeader=httpConnection.getHeaderFieldKey(i); F0@Qgk]\  
if(sHeader!=null) FJO"|||Y'|  
{ .CVUEK@Z4  
if(sHeader.equals("Content-Length")) C@*%A
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{ S3SV.C:z>  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?QGm
oQ)  
break; z)5S^{(  
} ! mm5I#s  
} Ds{{J5Um%  
else ?3`q+[:  
break; PKi_Zh.D  
} }c} ( 5  
} >4,{6<|  
catch(IOException e){e.printStackTrace ();} pJd0k"{  
catch(Exception e){e.printStackTrace ();} L'>s(CR  
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Utility.log(nFileLength); mKV'jm0  
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return nFileLength; "LOnDa7E^  
} Yj) e$f  
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//保存下载信息（文件指针位置） )7W6-.d  
private void write_nPos() qtHfz"p  
{ K'NcTw#f  
try{ 9SY(EL  
output = new DataOutputStream(new FileOutputStream(tmpFile)); NH'iR!iGo  
output.writeInt(nStartPos.length); wy''tqg6  
for(int i=0;i<nStartPos.length;i++) Rvvh{U;t  
{ &Cq{ _M  
// output.writeLong(nPos); z!:'V]  
output.writeLong(fileSplitterFetch.nStartPos); ^|aNG`|O  
output.writeLong(fileSplitterFetch.nEndPos); co/7lsW  
} " \:ced  
output.close(); "IG+V:{ou  
} +3Y!xD?=  
catch(IOException e){e.printStackTrace ();} 2/@D7>F&g  
catch(Exception e){e.printStackTrace ();} O-j$vzHpdY  
} 8a9RML}G<  
>!}`%pk(  
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//读取保存的下载信息（文件指针位置） n>P!u71  
private void read_nPos() 7UKYmJk.  
{ }~Q5Y3]#~  
try{ Q2eXK[?*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L,~MicgV  
int nCount = input.readInt(); 6Nt
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nStartPos = new long[nCount]; c&f y{}10  
nEndPos = new long[nCount]; 1TjZ#yP%1  
for(int i=0;i<nStartPos.length;i++) aX
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{ 9cQ_mgch  
nStartPos = input.readLong(); nLy#|C  
nEndPos = input.readLong(); Qw?+!-7TN  
} C c*({  
input.close(); tWY2o3j  
} ''S&e  
catch(IOException e){e.printStackTrace ();} LmQ/#Gx  
catch(Exception e){e.printStackTrace ();} K;U39ofW  
} WA.AFt  
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private void processErrorCode(int nErrorCode) $%PVJs  
{ e"Rm_t  
System.err.println("Error Code : " + nErrorCode); %y"J8;U  
} \ZD[!w7  
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//停止文件下载 5|w&dM  
public void siteStop() ~ y;y(4<  
{ 8$vK5Dnn8  
bStop = true; <y)E>Fl  
for(int i=0;i<nStartPos.length;i++) +l?; )  
fileSplitterFetch.splitterStop(); Yv)aAWEa  
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} ALGgAX3t  
} c8A`<-\MfB  
//负责部分文件的抓取 V5"HwN+`  
**FileSplitterFetch.java IfV 3fJ7  
*/ q0O&UE)6Y  
package NetFox; 0JY WrPR  
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import java.io.*; %f&< wC  
import java.net.*; SwH2$:f  
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public class FileSplitterFetch extends Thread { :b/jNHJU  
8
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String sURL; //File URL h`5)2n+P  
long nStartPos; //File Snippet Start Position >dQK.CG  
long nEndPos; //File Snippet End Position N/~N7MwJj  
int nThreadID; //Thread's ID |(% u}V?  
boolean bDownOver = false; //Downing is over .px:e)iW  
boolean bStop = false; //Stop identical *'ZN:5%H  
FileAccessI fileAccessI = null; //File Access interface Vhg1/EgUr  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException l@~LV}BI  
{ @Doyt{|T  
this.sURL = sURL; xiM&$<LpR  
this.nStartPos = nStart; IFuZ]CBz  
this.nEndPos = nEnd; X-JV'KE}^z  
nThreadID = id; TGV  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 UAYd?r  
} c[cAUsk i  
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public void run() #DI$
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{ &ITuyGmF  
while(nStartPos < nEndPos && !bStop) +,flE=5]s  
{ F^kwdS  
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try{ O`W%Tr  
URL url = new URL(sURL); F 3RB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n2ndjE$  
httpConnection.setRequestProperty("User-Agent","NetFox"); CjL<RJR=  
String sProperty = "bytes="+nStartPos+"-"; NHaMo*xQ  
httpConnection.setRequestProperty("RANGE",sProperty); 4j'd3WGpbN  
Utility.log(sProperty); %mI~ =^za  
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InputStream input = httpConnection.getInputStream(); $Ua56Y  
//logResponseHead(httpConnection); e~\QE0Oe:  
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byte[] b = new byte[1024]; $k2)8#\  
int nRead; 5cfA;(H  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Q~,YbZ-7  
{ E5G{B'%j  
nStartPos += fileAccessI.write(b,0,nRead); UpUp8%fCU  
//if(nThreadID == 1) YUkud2,j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z=$T1|  
} >Hwc,j q  
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Utility.log("Thread " + nThreadID + " is over!"); )ly ^Ox  
bDownOver = true; >SI<rR[~%  
//nPos = fileAccessI.write (b,0,nRead); 1;r69e  
} ;4~U,+Av  
catch(Exception e){e.printStackTrace ();} Tj`5L6N;8  
} 4\2V9F{s  
} bI ITPxz  

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//打印回应的头信息 H7&xLYQ2  
public void logResponseHead(HttpURLConnection con) I3y9:4  
{ Z`_.x &Y  
for(int i=1;;i++) B@K[3  
{ tJZc/]%`H  
String header=con.getHeaderFieldKey(i); }STYG`  
if(header!=null) T[uDZYx  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  v[,Src  
Utility.log(header+" : "+con.getHeaderField(header)); M7dU@Ag  
else M<`|CVl  
break; iS: #o>  
} ~L?nq@DL  
} $|<m9CW  
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public void splitterStop() >P(`MSc  
{ fE;Q:# Z.  
bStop = true; Q:o7G|C  
} P]6}\ ]~  
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} h4`9Cfrq,  
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/* RQ' H!(K  
**FileAccess.java @.9I3E-=  
*//文件访问(定位，写) Y;Y1+jt  
package NetFox; 8;zDg$(  
import java.io.*; v'ay.oVzw  
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public class FileAccessI implements Serializable{ F!g;A"?V  
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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 p@I9<^"
 
RandomAccessFile oSavedFile; la, h  
long nPos; =*MR(b>  
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public FileAccessI() throws IOException '}{?AUDx  
{ !#WqA9<  
this("",0); S/Oxr%H  
} *\ECf.7jz  
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public FileAccessI(String sName,long nPos) throws IOException c> ~:dcy  
{ !,bPe5?Ql  
oSavedFile = new RandomAccessFile(sName,"rw"); =,:K)  
this.nPos = nPos; A3yi?y{[*  
oSavedFile.seek(nPos); eyB_l
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} |]ucHV  

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public synchronized int write(byte[] b,int nStart,int nLen) F`&>NQb  
{ -9&g[  
int n = -1; A*0*sZ0  
try{ 14l; *  
oSavedFile.write(b,nStart,nLen); (%DRt4u<H  
n = nLen; YFvgz.>QE  
} UR:n5V4  
catch(IOException e) 0k1MKzi Q  
{ j|4tiv>  
e.printStackTrace (); %b<%w   
} 
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return n; Q8Te'1Ln!  
} \=g!$  
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} CWMlZVG  
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/* Cyf]`*  
**SiteInfoBean.java Sf/W9Jw  
*/ 9|a)sb7/  
package NetFox; :SeLkQC  
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public class SiteInfoBean { _z%\
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private String sSiteURL; //Site's URL f#c BQ~  
private String sFilePath; //Saved File's Path $68 XZCx  
private String sFileName; //Saved File's Name !vrnoFVu  
private int nSplitter; //Count of Splited Downloading File .-%oDuB5zF  
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public SiteInfoBean() l~{T#Q  
{//nSplitter的缺省值为5 {4)5]62>u  
//default value of nSplitter is 5 v/(__xN`B  
this("","","",5); c0hdLl;5  
} dcR6KG8  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) C}bPv+t  
{ "mG!L$  
sSiteURL= sURL; y
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sFilePath = sPath; |:/ @t  
sFileName = sName; +E `06
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this.nSplitter = nSpiltter; GdL4|xv  
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} @]<DR*<  
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public String getSSiteURL() oRV]p  
{
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return sSiteURL; [lrmuf  
} <"{+  
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public void setSSiteURL(String value) [v~Uy$d\  
{ E)RI!0Ra  
sSiteURL = value; ]Oig..LJ  
} EPR(i#xU  
 |UABar b  
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public String getSFilePath() #r-j.f}yx  
{ deHY8x5uI  
return sFilePath; a [0N,t  
} t Qp*'  
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public void setSFilePath(String value) !Q<8c =f  
{ q^Q|.&_k /  
sFilePath = value; =kyJaT^5[  
} EXv\FUzo  
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".Tf<F  
public String getSFileName() Xd90n>4S  
{ |% la  
return sFileName; 8HHgN`_  
} S]Yu6FtWiO  
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public void setSFileName(String value) rPrEEWS0)  
{ )dUd`g  
sFileName = value; s\F EA"w/  
} s8/ozaeo  
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public int getNSplitter() D0,o
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{ ^D>/wX\u  
return nSplitter; vQ9xG))  
} uL qpbn  
&@
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public void setNSplitter(int nCount) T-<>)N5y  
{  A[wxa
  
nSplitter = nCount; $! fz~  
} k;AV;KWI'  
} X(0:zb,#G*  
10QNV=yK7s  
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/* SIyS.!k>  
**Utility.java )PLc+J.I  
*/ {H"=PYR  
package NetFox; cZ7F1H~  
fmT3Afl5c  
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public class Utility { *N&^bF"SF  
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public Utility() @)!1#^(}%  
{ 6A{s%v H  
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} c]:J/'vc  
a 7mKshY(  
//线程睡眠 *T}dv)8  
public static void sleep(int nSecond) ^ZViQ$a"h;  
{ /*xmv $  
try{ ybuSqFy`$  
Thread.sleep(nSecond); D%";!7u  
} ysw6hVb  
catch(Exception e) hH@o|!y  
{ hdNZ":1s  
e.printStackTrace (); p|O-I&Xd  
} @kg
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} 3dzqVaV  
1(\I9L&J   
//日志 &,gryBN  
public static void log(String sMsg) e]y=]}A3{  
{ :_[cT,3  
System.err.println(sMsg); Dg2#Gv0B  
} <`VJU2  
;V(}F!U\z  
Ga/\kO)x_  
public static void log(int sMsg) nr9#3Lb  
{ pU)3*9?cIl  
System.err.println(sMsg); {/VL\AW5$  
} H_nOE(i<z  
} tS.b5$Q  
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3@WI*PMc  
/* ;>x1)|n5  
**TestMethod.java  !6i  
*/ 8 $*cfOC  
package NetFox; /iJhCB[QZ  
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'MM~~:  
public class TestMethod { {]^%?]e  

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public TestMethod() 8X~vJ^X9@y  
{ ///xx/weblogic60b2_win.exe ^xu)~:} i  
try{ ~$
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SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]KPg=@Q/  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); vh{1u  
SiteFileFetch fileFetch = new SiteFileFetch(bean); RBojT   
fileFetch.start(); <:}AC{I  
} E$zq8-p|  
catch(Exception e){e.printStackTrace ();} T{J`t*Ym  
9'L0Al~L  
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} @^jLYu|W  
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public static void main(String[] args) !suiqP1\*  
{ iKTU28x  
new TestMethod(); )C0X]?  
} cO?
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} 7^e}|l  
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