http断点续传简单实现（java)

/* @"B"*z-d  
**SiteFileFetch.java ^o`;C\  
*/ D_n(T')  
package NetFox; c:%ll&Xtn  
import java.io.*; }p2YRTHx  
import java.net.*; P, (#' W  
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public class SiteFileFetch extends Thread { az5 $.  
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SiteInfoBean siteInfoBean = null; //文件信息Bean g\Ck!KJ/y  
long[] nStartPos; //开始位置 -+#QZ7b  
long[] nEndPos; //结束位置 Vh%=JL sK  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :$=r^LSH  
long nFileLength; //文件长度 FZUN*5`  
boolean bFirst = true; //是否第一次取文件 w_O3];  
boolean bStop = false; //停止标志 5*Wo
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File tmpFile; //文件下载的临时信息 dnZA+Pa  
DataOutputStream output; //输出到文件的输出流 y.pwj~s  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） (T0%oina  
public SiteFileFetch(SiteInfoBean bean) throws IOException bZf18lvij:  
{ rKK{*%n  
siteInfoBean = bean; UK{6Rh ;  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .Xq4QR .  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7'pmW,;  
if(tmpFile.exists ()) n/>^!S  
{ @k"Q e&BQ  
bFirst = false; :Adx7!6  
read_nPos(); ,};UD  W  
} h3}gg@Fm  
else s
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{ yA74Rxl*6  
nStartPos = new long[bean.getNSplitter()]; 9GH11B_A  
nEndPos = new long[bean.getNSplitter()]; u{Z 4M3U  
} +lK?)77f  
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} C(RZ09,.S  
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public void run() ?1+JBl~/d  
{ J\WUBt-M  
//获得文件长度 dtXAEL\q  
//分割文件 mX4u#$xs:  
//实例FileSplitterFetch Z= 'DV1A$,  
//启动FileSplitterFetch线程 I UMt^z  
//等待子线程返回 ^rHG#^hA  
try{ ZSB_OS[N  
if(bFirst) X=sC8Edx  
{ s>pOfXIx  
nFileLength = getFileSize(); ,3m]jp'  
if(nFileLength == -1) IvW%n(a8^  
{ LjE@[@d  
System.err.println("File Length is not known!"); U\crp T`  
} X^2Txm d  
else if(nFileLength == -2) E3p3DM0F$  
{ u]D>O$_ s  
System.err.println("File is not access!"); RB\0o,mw4  
} ~^6[SbVb  
else ?Re6oLm<B  
{ J ejDF*Q  
for(int i=0;i<nStartPos.length;i++) ?u*gKI  
{ n$jOk |W  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); MS_@ Xe  
} 5BztOYn,  
for(int i=0;i<nEndPos.length-1;i++) 0n'~wz"wB  
{ 5tSR2gG#K,  
nEndPos = nStartPos[i+1]; 7tEK&+H`  
} p1-bq:  
nEndPos[nEndPos.length-1] = nFileLength;  AU3Ou5  
} 5|4
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}
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//启动子线程 u-31$z<<5}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 
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for(int i=0;i<nStartPos.length;i++) POnI&y]
  
{ SkmLX@:(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M-K.[}}-d  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), h1y6`m9  
nStartPos,nEndPos,i); L\:f#b~W  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SGZ]
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fileSplitterFetch.start(); fs43\m4=m  
} r35'U#VMk?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~miRnW*x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); o(2tRDT\_b  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", P ~pC /z  
nEndPos = " + nFileLength); &ye,A(4  
// fileSplitterFetch[nPos.length-1].start(); wRc=;f  
X_j=u1*5  
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//等待子线程结束 >N&C-6W  
//int count = 0; x6d0y
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//是否结束while循环 h`_@eax  
boolean breakWhile = false; *=6,}rX"I  
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while(!bStop) bZ/4O*B  
{ &oA p[]  
write_nPos(); ,>DaS(  
Utility.sleep(500); ;}=4z^^5  
breakWhile = true; qtx5N)J6  
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for(int i=0;i<nStartPos.length;i++) RWN2P6  
{ R)%1GG4  
if(!fileSplitterFetch.bDownOver) yf2I%\p}  
{ 5i 6*$#OM_  
breakWhile = false; *jB
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break; g_2m["6*  
} AADvk_R  
} :4{;^|RgU  
if(breakWhile) WWO@ULGY  
break; V4('}Q!  
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97$1na3gq  
//count++; #WOb&h  
//if(count>4) 7c:5Ey  
// siteStop(); aCL_cVOMR  
} W?(^|<W  
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System.err.println("文件下载结束！"); ]^=
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} *kI1NchF  
catch(Exception e){e.printStackTrace ();} a ]PS`  
} Jkc1ih`^  
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//获得文件长度 64#6L.Q-c  
public long getFileSize() n*4N%yI^m5  
{ W|go*+`W%
 
int nFileLength = -1; GM5s~,  
try{ Ly0U')D:  
URL url = new URL(siteInfoBean.getSSiteURL()); A.mIq
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HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [M^ur%H  
httpConnection.setRequestProperty("User-Agent","NetFox"); `=]I-5#.W  
/K#t$
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int responseCode=httpConnection.getResponseCode(); ]Z@+ |&@L  
if(responseCode>=400) vFKt=o$ g  
{ .kBZ(`K  
processErrorCode(responseCode); l )hg!(  
return -2; //-2 represent access is error Hkc:B/6
 
} ~}SOd<n)|  
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$ }u,uI  
String sHeader; /r4QDwu  
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for(int i=1;;i++) %-Z0OzWe  
{ 4_`ss+gk  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #>SvYP  
//Utility.log(in.readLine()); ]"Do%
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sHeader=httpConnection.getHeaderFieldKey(i); nUZ+N)*  
if(sHeader!=null) Cq7EdK;x  
{ 'xO^2m+N;  
if(sHeader.equals("Content-Length")) Vx]{<}(gr  
{ n3-2;xuNKE  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); zuWfR&U|W  
break; D@Zb|EI%<  
}
I|6wPV?  
} Unl6?_  
else _&/FO{F@m  
break; va(ZGGS]N  
} ]M"l-A  
} ^JDiI7  
catch(IOException e){e.printStackTrace ();} 29+p|n
 
catch(Exception e){e.printStackTrace ();} (_}w4N#  
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Utility.log(nFileLength); P|"U  
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return nFileLength; htn"rY(  
} sA3=x7j%c  
^-CQ9r*  
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//保存下载信息（文件指针位置） AZmABl  
private void write_nPos() [:HT=LX3  
{ ]-o0HY2  
try{ zSYh\
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output = new DataOutputStream(new FileOutputStream(tmpFile)); ZMSP8(V  
output.writeInt(nStartPos.length); 0]dL;~0y.  
for(int i=0;i<nStartPos.length;i++) q@;z((45  
{ ''9FB5
 
// output.writeLong(nPos); +4kBd<0Y  
output.writeLong(fileSplitterFetch.nStartPos); ~Wq[H  
output.writeLong(fileSplitterFetch.nEndPos); J?ljqA}i  
} ]jUxL=]r  
output.close(); LL~bq(b  
} w[>/(R7im  
catch(IOException e){e.printStackTrace ();} {+V1>6  
catch(Exception e){e.printStackTrace ();} 3{mu77  
} 0@R @L}m  
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//读取保存的下载信息（文件指针位置） D`;Q?fC  
private void read_nPos() l vuoVINEp  
{ c}nXMA^^  
try{ L< MIl[z7  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); EwSE;R -  
int nCount = input.readInt(); c\.8hd=<  
nStartPos = new long[nCount]; mdu5aL  
nEndPos = new long[nCount]; #ii,GN~N  
for(int i=0;i<nStartPos.length;i++) JW!SrM xF  
{ G)A5;u\P9  
nStartPos = input.readLong(); &j@i>(7  
nEndPos = input.readLong(); 1*_wJ  
} -[kbHrl&  
input.close(); zOR  
} <r*A(}Y  
catch(IOException e){e.printStackTrace ();} 33O@jbs@  
catch(Exception e){e.printStackTrace ();} /aepE~T  
} l<7)uO^8  
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private void processErrorCode(int nErrorCode) ,+0>p  
{ 9JHu{r"M  
System.err.println("Error Code : " + nErrorCode); qMAH~P0u  
} ;c5Q"  
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lNSB "S  
//停止文件下载 :@6,|2be=  
public void siteStop() G]fl33_}l  
{ lx<]v^  
bStop = true; tA+ c  
for(int i=0;i<nStartPos.length;i++) mZVYgJQ[  
fileSplitterFetch.splitterStop(); /cBQE=]6  
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} _"8\k7S*  
} 56Q9RU(M  
//负责部分文件的抓取 b {e nD  
**FileSplitterFetch.java 8=^o2&  
*/ $=8?@My<  
package NetFox; ?`Oh]2n)6  
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import java.io.*; RVmD&  
import java.net.*; v*Qr(4  
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public class FileSplitterFetch extends Thread { u 89u#gCAC  
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String sURL; //File URL T,h,)|:I^  
long nStartPos; //File Snippet Start Position ]XEkQ  
long nEndPos; //File Snippet End Position &Y
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int nThreadID; //Thread's ID ~%9ofXy  
boolean bDownOver = false; //Downing is over pPcn F`A  
boolean bStop = false; //Stop identical #`6A}/@.+  
FileAccessI fileAccessI = null; //File Access interface h<oQ9zW
)  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +>N/q(l  
{ \*#9Ry^f  
this.sURL = sURL; QE7 r{  
this.nStartPos = nStart; >= Hcw  
this.nEndPos = nEnd; p1 tfN$-  
nThreadID = id; ^a@Vn\V1  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 4a;8XAl  
} rJJI<{$  
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#chd  
/IM5#M5~  
public void run() sa8Sy&X"  
{ 24 S,w>j  
while(nStartPos < nEndPos && !bStop) t@-:e^ v  
{ I(r^q"  
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try{ &UG7 g  
URL url = new URL(sURL); rvRtR/*?j  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 372ewh3'  
httpConnection.setRequestProperty("User-Agent","NetFox"); #`5 M( o  
String sProperty = "bytes="+nStartPos+"-"; \[&~.B  
httpConnection.setRequestProperty("RANGE",sProperty); >a98H4  
Utility.log(sProperty); SE+K"faKQ  
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InputStream input = httpConnection.getInputStream(); TL(L[  
//logResponseHead(httpConnection); KYY~ YP  
v2 [ l$  
#;'1aT  
byte[] b = new byte[1024]; _N~h#(  
int nRead; H"8+[.xBh  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) kStWsc$;+T  
{ ANh5-8y  
nStartPos += fileAccessI.write(b,0,nRead); >\b=bT@iM  
//if(nThreadID == 1) =)C}u6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ( q^umw  
} o>{+vwK  
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Utility.log("Thread " + nThreadID + " is over!"); t#mW`rGE_  
bDownOver = true; k3se<NL[  
//nPos = fileAccessI.write (b,0,nRead); Zs!)w9y&V  
} WF<0QH  
catch(Exception e){e.printStackTrace ();} ;pdW7  
} emb~
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} OL*EY:]  
fRJSo%  
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//打印回应的头信息 KLlo^1.<  
public void logResponseHead(HttpURLConnection con) _$"qC[.  
{ 8%Zl;;W  
for(int i=1;;i++) pDD0 QO  
{ [vpZ3
;  
String header=con.getHeaderFieldKey(i); zw^jIg$  
if(header!=null) ^1U2&S  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); V0R
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Utility.log(header+" : "+con.getHeaderField(header)); 6sl*Ko[  
else r'fNQJ >  
break; !8ub3oj)  
} =!r9;L,?  
} $@q)IK%FDL  

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public void splitterStop() uYiM~^0  
{ Mq]~Ka3q7  
bStop = true; nK Rx_D$d  
} yB(^t`)}N  
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} (`
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/* :*TfGV  
**FileAccess.java h,<%cvU=  
*//文件访问(定位，写) iNf+ -C3  
package NetFox; J=W"FEXTL7  
import java.io.*; a;m-Vu!  
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+Ck<tx3h&  
public class FileAccessI implements Serializable{ {$4fRxj  
25h.u>6@{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 X:+;d8rCy  
RandomAccessFile oSavedFile; E N%cjvE  
long nPos; 1p>5ZkHb  
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public FileAccessI() throws IOException ^_KHw
 
{ -gH1`*YL  
this("",0); %1a\"F![  
} f&B&!&gZ  
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w<N[K>  
public FileAccessI(String sName,long nPos) throws IOException mZJ"e,AY  
{ hT9
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oSavedFile = new RandomAccessFile(sName,"rw"); fLAOA9  
this.nPos = nPos; PMjqcdBzm  
oSavedFile.seek(nPos); fZH:&EP  
} F))+a&O  
~oz8B^7i;  
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public synchronized int write(byte[] b,int nStart,int nLen) e?3 S0}  
{ D#508{)  
int n = -1; $/nU0W  
try{ W"YFx*W  
oSavedFile.write(b,nStart,nLen); uG&xtN8  
n = nLen; 8a|p`)lT  
} s2riayM9/  
catch(IOException e) XKLkJZN  
{ [GZ%K`wx  
e.printStackTrace (); E"&fT!yi  
} z'3  
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return n; |/[?]
`  
} jTaEaX8+  
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} `Q^G k{9P  

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/* g:`V:kbY$  
**SiteInfoBean.java Wcl@H @  
*/ w
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package NetFox; 3|-)]^1O  
gI6./;;x  
p ElF,Y  
public class SiteInfoBean { DG}t!  
>`Gys8T  
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private String sSiteURL; //Site's URL Q3u P7j  
private String sFilePath; //Saved File's Path m^@,0\F  
private String sFileName; //Saved File's Name c?"#x-<1s  
private int nSplitter; //Count of Splited Downloading File 5;oWF
l  
BV"7Wp;  
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public SiteInfoBean() l4u_Z:<w  
{//nSplitter的缺省值为5 rePJ4i [y  
//default value of nSplitter is 5 {<o_6 z`$  
this("","","",5); yNi/JM  
} p)RASIB  
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7'z{FSS  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) puA~}6C  
{ iyAeR!`  
sSiteURL= sURL; v#{Sx>lO  
sFilePath = sPath; C:xgM'~+  
sFileName = sName; x hBlv  
this.nSplitter = nSpiltter; ,<0R'R  
XT> u/Z)  
!E8y!|7$  
} 3#`_
t :"A  
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public String getSSiteURL() P!3)-apP\  
{ IWERn v!  
return sSiteURL; W0J d2*]  
} @{3$H^  
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=v]\{.  
public void setSSiteURL(String value) Z5/^pyc  
{ <]xGd!x$  
sSiteURL = value; \/J>I
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} }m0*w3  
@(M-ZO!D  
{fFZ%$  
public String getSFilePath() uOUgU$%zqH  
{ UJMM&  
return sFilePath; s.`:9nj  
} jcD_<WSe  
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public void setSFilePath(String value) k/o"E  
{ EKo!vieG  
sFilePath = value; _b|mSo,{Y  
} #{KYsDtvx  
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/5 yjON{  
public String getSFileName() FFX-kS  
{ 0=O(+ yi  
return sFileName; nb d
m@  
} uNSaw['0j  
@a2n{  
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public void setSFileName(String value) ?_)b[-N!  
{ [Z9 lxZ|  
sFileName = value; Tq{+9+
 
} dZ}gf}.v  
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g<U\7Vp\1  
public int getNSplitter() NU[{ANbl  
{ ._'AJhU$0  
return nSplitter; z,dh?%H>X  
} hS&3D6Gt  
IlN: NS  
#$W02L8  
public void setNSplitter(int nCount) 0T,uH  
{ /2z, ?,jL  
nSplitter = nCount; OBY^J1St  
} y0s=yN_  
} HXV4E\JA  
&JMp)zaI[  
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/* 8LuM eGs  
**Utility.java >}<1  
*/ Xb#!1hA  
package NetFox; E,IeW {6s  
h;" 9.  
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public class Utility { x6yYx_  
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public Utility() $O nh2 ^  
{ |)~t^  
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} FK;3atrz  
5<64 C}fE3  
//线程睡眠 w{F{7X$^  
public static void sleep(int nSecond) |ppG*ee  
{ "06t"u<%  
try{ I
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Thread.sleep(nSecond); j-]`;&L  
} 7pPaHX8  
catch(Exception e) h;TN$ /
 
{ -sjyv/%_  
e.printStackTrace (); [vv $"$z  
} ,X`w/ 2O  
} ya3k;j2C  
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//日志 'Fq+\J#%  
public static void log(String sMsg) @!'rsPrI  
{ 6LRvl6ik  
System.err.println(sMsg); SG$V%z"e  
} m3T=x =  
_c!$K#Yl{  
j!c~%hP  
public static void log(int sMsg) r=}v` R&  
{ sdp3geBYo  
System.err.println(sMsg); #jj+/>ZOi  
} `;j@v8n$*  
} HQkK8'\LP  
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/* 'G>$W+lT^  
**TestMethod.java i0}f@pCB?X  
*/ 0RZ[]:(  
package NetFox; 
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l  
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public class TestMethod { X 0vcBHh  

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public TestMethod() <uG6!P  
{ ///xx/weblogic60b2_win.exe 5Z@0XI  
try{ )L/0X40<.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Z".Xroq~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .G
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SiteFileFetch fileFetch = new SiteFileFetch(bean); 6?(yMSKa  
fileFetch.start(); 3N[Rrxe2  
} Y_zMj`HE  
catch(Exception e){e.printStackTrace ();} xovsh\s  
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zq(4@S-TU  
} zm!M'|~@7  
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X$2f)
3  
public static void main(String[] args) zJ6""38Pr  
{ %?hvN  
new TestMethod(); y{KYR)  
} q6PG=9d0B  
} S4U}u l  
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