http断点续传简单实现（java)

/* > -OQk"o  
**SiteFileFetch.java UoCFj2?C  
*/ s${ew.eW  
package NetFox; a~jM^b;VN  
import java.io.*; G<U MZg  
import java.net.*; Hn+w1v&3  
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public class SiteFileFetch extends Thread { dX?8@uzu  
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SiteInfoBean siteInfoBean = null; //文件信息Bean &N.D!7X  
long[] nStartPos; //开始位置 u6j\@U6I  
long[] nEndPos; //结束位置 q3<Pb,Z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :=3Ty]e  
long nFileLength; //文件长度 }j;*7x8(  
boolean bFirst = true; //是否第一次取文件 *DcJ).  
boolean bStop = false; //停止标志 :_X9x{  
File tmpFile; //文件下载的临时信息 eTw sh]  
DataOutputStream output; //输出到文件的输出流 gZ8n[zxf6  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ~RgO9p(dY  
public SiteFileFetch(SiteInfoBean bean) throws IOException UsP1bh4  
{  E|P  
siteInfoBean = bean; !lpKZG  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !36jtKdM  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 4Hc+F(  
if(tmpFile.exists ()) q$7SJ.pF  
{ }}y~\TB~}  
bFirst = false; ~`~mnlN  
read_nPos(); ))JbROBU,  
} ~\<aj(m(|  
else 7#wdBB%  
{ [<CIh46S.  
nStartPos = new long[bean.getNSplitter()]; os9X)G  
nEndPos = new long[bean.getNSplitter()]; 1w*DU
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} U51C /A  
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} LX5, _`B  
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public void run() ?(rJ  
{ SFP%UfM<  
//获得文件长度 V 3?x_p
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//分割文件 LVt{`   
//实例FileSplitterFetch D; i%J  
//启动FileSplitterFetch线程 T$
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//等待子线程返回 i^`]TOP  
try{ ^FJ.C|l(  
if(bFirst) y(!J8(yA  
{ `IN/1=]5  
nFileLength = getFileSize(); AM?62  
if(nFileLength == -1) ksb.]P d.  
{ N{rC#A3  
System.err.println("File Length is not known!"); 8Evon&G59  
} 4K{<R!2I  
else if(nFileLength == -2) ':Avh|q3N  
{ 6'E3Q=}d  
System.err.println("File is not access!"); ti%uyXfja  
} 
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else OZ2YflT  
{ 8y:c3jzP_  
for(int i=0;i<nStartPos.length;i++) 33/aYy  
{ c0}* $e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =GGt:3Kx-  
} oVDqX=G  
for(int i=0;i<nEndPos.length-1;i++) u^5X@.  
{ 98"/]ER
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nEndPos = nStartPos[i+1]; [R-&5 G!x  
} ~m@v ~=  
nEndPos[nEndPos.length-1] = nFileLength; dB`3"aSN7  
} Pi7IBz  
} bvpP/LeY  
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//启动子线程 `GGACH3#s  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; x|3f$ =b  
for(int i=0;i<nStartPos.length;i++) 1"7Rs}l7  
{ e&*< "WN  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UTT7a"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), q4Z9;^S  
nStartPos,nEndPos,i); c^Y&4=>T  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g3*" ^C2=  
fileSplitterFetch.start(); J^"  
} BC}+yS \  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X"'c2gaa_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); T8*<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", O:K={#Xj  
nEndPos = " + nFileLength);  B6| g2Tt  
// fileSplitterFetch[nPos.length-1].start(); X}
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^#:F8D  
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//等待子线程结束 X0IXj%\N  
//int count = 0; ?<7o\Xk#{  
//是否结束while循环 *p&c}2'  
boolean breakWhile = false; 8Df(|>mK  
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while(!bStop) 8+gti*C?\  
{ %x Xib9J  
write_nPos(); ze5Hg'f  
Utility.sleep(500); ?uiQ'}
 
breakWhile = true; F%<hng%k  
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for(int i=0;i<nStartPos.length;i++) -&3WN!egq  
{ H?ZlJ|/c  
if(!fileSplitterFetch.bDownOver) 7F=Xn@ _  
{ EKwA1,Xz  
breakWhile = false; : 5=E>!  
break; X}!r4<;(  
} Sw<V/t  
} s*blZdP  
if(breakWhile) Mwm=r//  
break; _9@D o6  
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//count++; i
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//if(count>4) >%vw(pt  
// siteStop(); T!GX^nn*O  
} Z33&FUU  
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System.err.println("文件下载结束！"); F.nJXZnJ  
} o\Ocu>:  
catch(Exception e){e.printStackTrace ();} [#}A]1N  
} }4 p3m]  
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Y;JPr  
//获得文件长度 >o\s'i[  
public long getFileSize() fWr6f`de  
{ AYB =iLa  
int nFileLength = -1; J?Y1G<&  
try{ 0)c9X[sG  
URL url = new URL(siteInfoBean.getSSiteURL()); A..,.   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \dIc_6/D1  
httpConnection.setRequestProperty("User-Agent","NetFox"); !>%U8A  
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int responseCode=httpConnection.getResponseCode(); %TO=]>q  
if(responseCode>=400) %D::$,;<<  
{ m5m'ByX(*  
processErrorCode(responseCode); Y5J}*`[Mr  
return -2; //-2 represent access is error o_!=-AWV  
} m-{t%[Y  
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String sHeader; 7N@4c   
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for(int i=1;;i++) i&|fGX?-I  
{ Y Me
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//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); +3@d]JfMh  
//Utility.log(in.readLine()); BE&P/~(C  
sHeader=httpConnection.getHeaderFieldKey(i); I=N;F6  
if(sHeader!=null) bu;3Ib3\  
{ ,&wTUS\  
if(sHeader.equals("Content-Length")) D][e u
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{ M7$ h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); uxbDRlOS  
break; |*~=w J_  
} Jd].e=]pN  
} kG =nDy  
else rZ.,\ X_  
break; kh11Y1Q0d  
} 
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} yM
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catch(IOException e){e.printStackTrace ();} @uIY+_E40g  
catch(Exception e){e.printStackTrace ();} lq4vX^S  
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Utility.log(nFileLength); 5&
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return nFileLength;  -jBk  
} fS( )F*J  
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//保存下载信息（文件指针位置） n?@3+wG  
private void write_nPos() c"vF i~Db  
{ f zu#!  
try{ q&eUw<(F  
output = new DataOutputStream(new FileOutputStream(tmpFile)); M<f=xY2$v  
output.writeInt(nStartPos.length); EYe)d+E*  
for(int i=0;i<nStartPos.length;i++) 2TR l@  
{ ?J;*  
// output.writeLong(nPos); %s]l^RZ  
output.writeLong(fileSplitterFetch.nStartPos); c=S-g 9J  
output.writeLong(fileSplitterFetch.nEndPos);
|!0R"lv'u  
} z8#c!h<@;  
output.close(); $6~ \xe=  
} 410WWR&4_  
catch(IOException e){e.printStackTrace ();} 8J&K_JC^  
catch(Exception e){e.printStackTrace ();} m,zZe}oJ  
} o_2mSD
!  
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//读取保存的下载信息（文件指针位置） +y+-~;5iv  
private void read_nPos() {gSR49!Q  
{ i-Le&  
try{ 0(owFNUBs  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #3:;&@#  
int nCount = input.readInt(); ]Q}z-U  
nStartPos = new long[nCount]; |( %3'"Z  
nEndPos = new long[nCount]; 9!XW):  
for(int i=0;i<nStartPos.length;i++) =c
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{ >[4;K&$B  
nStartPos = input.readLong(); myp}DI(  
nEndPos = input.readLong(); Y,v8eOo45S  
} kg2?IL  
input.close(); ?}QHEk:H  
} 8&AHu  
catch(IOException e){e.printStackTrace ();} bLx70$  
catch(Exception e){e.printStackTrace ();} fk(l.A$  
} 4:!KtpR[O  
#8N9@  
!fFmQ\|)4S  
private void processErrorCode(int nErrorCode) "}uPz4  
{ !Ua74C
 
System.err.println("Error Code : " + nErrorCode); R~-r8dWcw  
} {.W$<y (j7  
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//停止文件下载 !ul)e;a  
public void siteStop() |51z&dG  
{ )^&,[Q=i  
bStop = true; Zi+>#kDV  
for(int i=0;i<nStartPos.length;i++) ~I0I#_$'P  
fileSplitterFetch.splitterStop();  b;!oPT  
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} Dh*>361y-  
} y{Wtm7fnA  
//负责部分文件的抓取 #S[:Q.0 ;  
**FileSplitterFetch.java G0sg\]  
*/ F,CQAgx  
package NetFox;  T)o)%Yv  
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import java.io.*; 5a9PM(  
import java.net.*; MB<oWH[e)  
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public class FileSplitterFetch extends Thread { `pp"htm   
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String sURL; //File URL UQl3Tq4QM  
long nStartPos; //File Snippet Start Position !<"H73?fl  
long nEndPos; //File Snippet End Position -9"hJ4  
int nThreadID; //Thread's ID f-5vE9G3y7  
boolean bDownOver = false; //Downing is over .tB[8Y=J  
boolean bStop = false; //Stop identical
 D7%`hU  
FileAccessI fileAccessI = null; //File Access interface w.qpV]9>  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $'}:nwq6x  
{ + M2|-C  
this.sURL = sURL; V@jR8zv|_  
this.nStartPos = nStart; )W&H{2No  
this.nEndPos = nEnd;
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nThreadID = id; P,Fs7  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %g3@m5&  
} 3@e#E4+ff  
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public void run() M%f96XUM  
{ i(q%E
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while(nStartPos < nEndPos && !bStop) <C\snB  
{ /H+j6*}r  
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try{  MD~03  
URL url = new URL(sURL); gIS<"smOo  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }q-_|(b;  
httpConnection.setRequestProperty("User-Agent","NetFox"); ugg08am!  
String sProperty = "bytes="+nStartPos+"-"; tP2hU[7Z  
httpConnection.setRequestProperty("RANGE",sProperty); >Pv#)qtm  
Utility.log(sProperty); #RoGyrLo  
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InputStream input = httpConnection.getInputStream(); &1:xY.Zs_  
//logResponseHead(httpConnection); :)+|q  
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byte[] b = new byte[1024]; ysA~Nq@  
int nRead; $b;9oST  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) H kDT14 `&  
{ r8XY"<
  
nStartPos += fileAccessI.write(b,0,nRead); 50Z$3T  
//if(nThreadID == 1) =LHE_ AA  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q4$zsw  
} sHO6y0P  
ml7]sN(  
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Utility.log("Thread " + nThreadID + " is over!"); $L>tV='  
bDownOver = true; e!*d(lHKos  
//nPos = fileAccessI.write (b,0,nRead); fU_itb(  
} [QA@XBy6  
catch(Exception e){e.printStackTrace ();} 0qSd#jO  
} i'|rx2]e  
} xtL_,ug  
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//打印回应的头信息 4w0 &f  
public void logResponseHead(HttpURLConnection con) vBCQ-l<Ub  
{ W[A;VOj0$  
for(int i=1;;i++) o Y_(UIa  
{ O<l_2?S1  
String header=con.getHeaderFieldKey(i); M(o?I}  
if(header!=null) l)`bm/k]V  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y4s]*?Wz  
Utility.log(header+" : "+con.getHeaderField(header)); 1]#qxjZ~  
else ]O s!=rt  
break; ),5^bl/  
} <R>qOX8  
} tF SO"  
%..{c#V  
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public void splitterStop() TI:-Y@8  
{ A:F*Y%ZW  
bStop = true; \?&P|7N  
} +N2?fgA  
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} p=jD "lq  
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/* E$m3Gg)s>N  
**FileAccess.java }s{RW<A  
*//文件访问(定位，写) OO
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package NetFox; ! FbW7"yE  
import java.io.*; 0V ,R|Ln  
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public class FileAccessI implements Serializable{ hv te)  
m/3b7c@r  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B<(v\=xZ  
RandomAccessFile oSavedFile; .T?9-`I9  
long nPos; XHcT7}]  
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public FileAccessI() throws IOException ^il'
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{ (1gfb*L  
this("",0); sL]KBux  
} '`=z52  
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public FileAccessI(String sName,long nPos) throws IOException v|`f8M2  
{ R"#DR^.;  
oSavedFile = new RandomAccessFile(sName,"rw"); 5an#,vCn{  
this.nPos = nPos; L31B:t^  
oSavedFile.seek(nPos); :%Na-j9hV)  
} Xu $_%+46  
@x?7J@:  
#rM/  
public synchronized int write(byte[] b,int nStart,int nLen) hu.c&Q>  
{ _x_om#~n  
int n = -1; EaGh`*"w(7  
try{ 5hak'#2  
oSavedFile.write(b,nStart,nLen); -S\7
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n = nLen; Z?|\0GR+`5  
} rr>*_67-:  
catch(IOException e) Q9=vgOW+  
{ ),y{.n:wm  
e.printStackTrace (); SDpaW6(_  
} _]H$rf,Rc  
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return n; ) D:M_T2  
} (5rH72g(  
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} _svY.ps*  
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/* TcA+ov>TD  
**SiteInfoBean.java Y,z15i3j?  
*/ q\*",xZxwz  
package NetFox; !fUrDOM0E  
syhTOhOX  
Y}%=:Yt  
public class SiteInfoBean { Q`}1 B   
52K_kB5  
+[M5x[[$  
private String sSiteURL; //Site's URL ;|&Ak_I2G  
private String sFilePath; //Saved File's Path YFgQ!\&59  
private String sFileName; //Saved File's Name OnFx8r:q@%  
private int nSplitter; //Count of Splited Downloading File AHX_I  
4HEp}Y"}V  
VE1 B"s</  
public SiteInfoBean() RGh`=D/yE  
{//nSplitter的缺省值为5 M0g!"0?  
//default value of nSplitter is 5 ~E&drl\  
this("","","",5); Wo&10S w  
} f@&C \  
'^"6EF.R  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) X+"8yZz3?  
{ 94Mh/A9k  
sSiteURL= sURL; _UKH1qUd4  
sFilePath = sPath; 1~NXCIdF  
sFileName = sName; sI4Q
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this.nSplitter = nSpiltter; 8"l9W=  
g &~T X  
}3 NGMGu$  
} ]X/1u"  
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Ld6j;ZJ';  
public String getSSiteURL() uSp=,2)  
{ 3lYM(DT  
return sSiteURL; N}Ozm6
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} +~mBo+ ,  
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public void setSSiteURL(String value) H~x,\|l#  
{ qYZ\<h^  
sSiteURL = value; j;@7
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} KY$
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public String getSFilePath() `~Nd4EA)2  
{ =;Gy"F1 dp  
return sFilePath; "pTyQT9P  
} "Wd?U[[  
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tAH,3Sz( /  
public void setSFilePath(String value) N6H/J_:  
{ 6KP"F[8I  
sFilePath = value; 6-C9[[g<  
} 0]3%BgZ(a8  
Hp;Dp!PLa  
OV ~|@{6T  
public String getSFileName() i~ D,  
{ u1d{|fF  
return sFileName; |Q2H^dU'rQ  
} &z;F'>"  
/]4[b!OTJ  
aW$(lf2;  
public void setSFileName(String value) /pzEL  
{ Gr6XqO_  
sFileName = value; E ?(+v  
} KA1Z{7UK%  
=\H.C@r  
:FOMRrf7.  
public int getNSplitter() ~3
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{ ]5b%r;_  
return nSplitter; %IGcn48J  
} lgp-/O"T  
ZVu&q{s,  
.nX+
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public void setNSplitter(int nCount) PEZ~og:w  
{ lAuI?/E  
nSplitter = nCount; RGy4p)z*+  
} }|>mR];  
} l?E7'OEF:  
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/* 8;>vgD  
**Utility.java @+1-_Q`s/R  
*/ Mrpn^C2)  
package NetFox; !7XAc,y  
Z!o&};_j  
@WVpDhG  
public class Utility { ImQ?<g8$  
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Enr8"+.(  
public Utility() )HWf`;VQ  
{ @mM'V5
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} _:F0>=$  
]F kLtq  
//线程睡眠 Ym IVtQ  
public static void sleep(int nSecond) XUeBK/aQ{  
{ g}nlb.b]{m  
try{ LO
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Thread.sleep(nSecond); xKIzEN &  
} "F%w{bf  
catch(Exception e) ta\AiHm  
{ _/0vmgQ&  
e.printStackTrace (); !U38aHG  
} =9@{U2 =l  
} !}fq%8"-  
t>;u;XY!;  
//日志 >-fOkOWXy  
public static void log(String sMsg) vL~nJv  
{ - `^594  
System.err.println(sMsg); P}B{FIpNG  
} /-BKdkBCpZ  
z45 7
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$,R QA^gxW  
public static void log(int sMsg) 6rlafISvO  
{ h3y0bV[g=  
System.err.println(sMsg); FWpcWmS`s  
} :^".cs?g  
} luD.3&0n  
W.b?MPy]  
^6Y4=  
/* $w{!}U2+-  
**TestMethod.java x#z}A&  
*/ %7WQb]y  
package NetFox; Z}74% 9qE  
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 )!2$yD  
public class TestMethod { @C7iflo6  
ht _fbh(l  
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public TestMethod() !#P|2>>u  
{ ///xx/weblogic60b2_win.exe 1"k"<{%  
try{ y7J2:/@[x  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); g_8Bhe"ik  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;w,+x 7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8nn%wps  
fileFetch.start(); .*+?]  
} 9Qja|;  
catch(Exception e){e.printStackTrace ();} f S-(Kmh  
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} f?)BAah  
y>}dKbCN  
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public static void main(String[] args) 3D<s
#  
{ dd4g?):  
new TestMethod(); 3Z.<=D  
} &K Ti[  
} *h59Vaoc  
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