http断点续传简单实现（java)

/* }Q^a.`h  
**SiteFileFetch.java Od]xIk+E  
*/ DMN H?6  
package NetFox; (#iM0{  
import java.io.*; V@'S#K#  
import java.net.*; "[S 6w  
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public class SiteFileFetch extends Thread { *+Q*&-$  
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SiteInfoBean siteInfoBean = null; //文件信息Bean %ys}Q!gR  
long[] nStartPos; //开始位置 @5G7bY7Nz  
long[] nEndPos; //结束位置 32P]0&_O  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 &*GX:0=/>  
long nFileLength; //文件长度 S)|b%mVwR  
boolean bFirst = true; //是否第一次取文件 =T4w:  
boolean bStop = false; //停止标志 u`@FA?+E1  
File tmpFile; //文件下载的临时信息 R0<Vd"  
DataOutputStream output; //输出到文件的输出流 N`6|Y  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） l*H"]6cXRL  
public SiteFileFetch(SiteInfoBean bean) throws IOException g9Gy3zk=  
{ r$
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siteInfoBean = bean; 
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//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); m9cT}x&j  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); r['C.S6  
if(tmpFile.exists ()) 9G/2^PI  
{ DJ0T5VE W3  
bFirst = false; \%Q rN+WQ  
read_nPos(); *v/*_6
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} :]QxT8B  
else oa !P]r  
{ G@!9)v]9  
nStartPos = new long[bean.getNSplitter()]; 1^^D :tt  
nEndPos = new long[bean.getNSplitter()]; S Tk#hhx  
} JHH&@Cn  
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} T["(YFCByg  
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public void run() ++"PPbOe&D  
{ <j3HT"^[D  
//获得文件长度 +qf{ '|H  
//分割文件 hO@3-SRa,k  
//实例FileSplitterFetch yv4PK*  
//启动FileSplitterFetch线程 Asu"#sd  
//等待子线程返回 Lo9?,^S  
try{ Vnb#N4vR  
if(bFirst) 3[Iw%% q  
{ }h6z&:qA[?  
nFileLength = getFileSize(); Yg?{x@  
if(nFileLength == -1) 0Jh:6F  
{ Ps\^OJR  
System.err.println("File Length is not known!"); t&]Mt7  
} f"^tOgGH  
else if(nFileLength == -2) >;W(Jb7e
 
{ 9(j!#`O7&  
System.err.println("File is not access!"); 6E]rxps}"  
} zAUfd[g  
else TeqsP1{?  
{ j~q`xv+
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for(int i=0;i<nStartPos.length;i++) Mwc3@  
{ {2@96o2}  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jMbK7 1K%  
} q:.BY}X9  
for(int i=0;i<nEndPos.length-1;i++) LWV`xCr8R  
{ -;"l5oX  
nEndPos = nStartPos[i+1]; J[wXG6M  
} 1_lL?S3,a@  
nEndPos[nEndPos.length-1] = nFileLength; -1JHhRr]  
} u`|fmVI  
} \]%U?`A  
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3/FB>w gt  
//启动子线程 oD\+ 5[x  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; @CF4:NNHw  
for(int i=0;i<nStartPos.length;i++) >O
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{ nVzo=+Yp  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V}qmH2h  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Dm#k-y  
nStartPos,nEndPos,i); p#2th`M:P1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 55p=veq \  
fileSplitterFetch.start(); 90}B*3x  
} F9W5x=EK\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), a~>h'}C>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); n]Y _C^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", }DaYO\:yK*  
nEndPos = " + nFileLength); kM`#U *j  
// fileSplitterFetch[nPos.length-1].start(); 9l]IE,u  
|3m%d2V*hF  
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//等待子线程结束 oVW?d]R  
//int count = 0; e_V(G
  
//是否结束while循环 p;Kr664  
boolean breakWhile = false; qE{S'XyM,  
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while(!bStop) 7i.aZ2a%  
{ n4johV.#  
write_nPos(); <H6Uo#ao  
Utility.sleep(500); %R"Fx$tQ  
breakWhile = true; \.] U  
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for(int i=0;i<nStartPos.length;i++) X)m2{@v D  
{ {'!~j!1'j  
if(!fileSplitterFetch.bDownOver) h# 8b#  
{ ty>O}9%  
breakWhile = false; -;}Wm[  
break; 6EY4@0%A  
} c&
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} E<dN=#f6  
if(breakWhile) &&O=v]6,V  
break; 2uVm?nm  
\`C3;}o:"P  
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//count++; x5ia<V>=d  
//if(count>4) mLE`IKgd]  
// siteStop(); z@~rm9d  
} *F0N'*  
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System.err.println("文件下载结束！"); jLTs1`I/F  
} D$HxPfDZ  
catch(Exception e){e.printStackTrace ();} zeX?]@]Y  
} GCHssw~P'v  
.+yJ'*i$d  
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//获得文件长度 bX,Z<BvbF  
public long getFileSize() EX_&wep@1  
{ RswR DLl  
int nFileLength = -1; <vs.Ucxx  
try{ F <(Y  
URL url = new URL(siteInfoBean.getSSiteURL()); y+a&swd2(U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Jp- hFD  
httpConnection.setRequestProperty("User-Agent","NetFox"); \Z8!iruN  
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int responseCode=httpConnection.getResponseCode(); v|6fqG+Q\  
if(responseCode>=400) y@I"Hk<T  
{ pN[i%\vh  
processErrorCode(responseCode); \XC1/LZQ  
return -2; //-2 represent access is error c{~*\&  
} *"@P2F&  
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String sHeader; /1*\*<cs  
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for(int i=1;;i++) TUG3#PSnm*  
{ Mtu8zm  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); x)*[>d2yd  
//Utility.log(in.readLine()); ]P.S5s'  
sHeader=httpConnection.getHeaderFieldKey(i); *h UrE  
if(sHeader!=null) 8QU`SoS9  
{ EOL03N  
if(sHeader.equals("Content-Length")) Jy9&=Qh   
{ 3I]5DW %-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); eX\t]{\oC  
break; ~F WmT(S  
} y^ohns5{  
} AWw'pgTQX  
else Lxl?6wZ  
break; ,~v1NK*  
} \2YhI0skW  
} 95}"AIi  
catch(IOException e){e.printStackTrace ();} 79\ =)m}$Q  
catch(Exception e){e.printStackTrace ();} "='|c-
x  
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Utility.log(nFileLength); ?pFHpz  
52
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return nFileLength; .fgoEB,(  
} @Z)&
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//保存下载信息（文件指针位置） 6`'^$wKs  
private void write_nPos() di"*K*~y  
{ [X|P(&\hQd  
try{ \-^3Pe,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); OA+W$
  
output.writeInt(nStartPos.length); d/e9LK  
for(int i=0;i<nStartPos.length;i++) 7{6wNc  
{ 5QlJX  
// output.writeLong(nPos); grZN.zTO  
output.writeLong(fileSplitterFetch.nStartPos); aD.A +es  
output.writeLong(fileSplitterFetch.nEndPos); H]cCyuCdH  
} Ou/{PK}  
output.close(); i+OyBDkJM!  
} Q?~l=}2  
catch(IOException e){e.printStackTrace ();} [.2>=3T  
catch(Exception e){e.printStackTrace ();} O?P6rX
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} ~`y6YIJ3  
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//读取保存的下载信息（文件指针位置） )pg?ZM9  
private void read_nPos() lm$T`:c  
{ iKu5K0x{>I  
try{ {L#Pdj{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); h>4\I;Ij  
int nCount = input.readInt(); XWkYhTaY  
nStartPos = new long[nCount]; HR4^+x  
nEndPos = new long[nCount]; &Oe,$%{hBh  
for(int i=0;i<nStartPos.length;i++) $#CkI09  
{ VQ+Xh  
nStartPos = input.readLong(); ^s^X nQhE  
nEndPos = input.readLong(); nfc&.(6x<  
} &",pPuq  
input.close(); OfPWqNpO  
} %N2=:;f  
catch(IOException e){e.printStackTrace ();} Hg<]5  
catch(Exception e){e.printStackTrace ();} }nkX-PG9  
}
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private void processErrorCode(int nErrorCode) RK|C*TCnl  
{ m!g f!  
System.err.println("Error Code : " + nErrorCode); lOql(ZH`w  
} Y6+nfh_  
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//停止文件下载 -e30!A  
public void siteStop() -|g~--@Q  
{ 0C7x1:  
bStop = true; G"wy?  
for(int i=0;i<nStartPos.length;i++) }.x?$C+\"  
fileSplitterFetch.splitterStop();  a(F%M  
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} ENygD  
} 66v6do7  
//负责部分文件的抓取 (Ori].{C.J  
**FileSplitterFetch.java kA fkQy(~  
*/ IG 6yt  
package NetFox; p;g$D=2  
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import java.io.*; LG(bdj"NM  
import java.net.*; <yBZsSj  
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public class FileSplitterFetch extends Thread { P/4]x@{ih  
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String sURL; //File URL :2}zovsdj  
long nStartPos; //File Snippet Start Position o@vo,J
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long nEndPos; //File Snippet End Position tv5G']vO\  
int nThreadID; //Thread's ID Fc{hzqaP8  
boolean bDownOver = false; //Downing is over 6Wl+5 a6V
 
boolean bStop = false; //Stop identical PE0A`  
FileAccessI fileAccessI = null; //File Access interface (]1n!  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException n)gzHch  
{ ) m[0,  
this.sURL = sURL; J;HkR9<C  
this.nStartPos = nStart; [?^,,.Dd  
this.nEndPos = nEnd; o/ ozX4C  
nThreadID = id; 9ELLJ@oNC  
fileAccessI = new FileAccessI(sName,nStartPos);//定位
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} ,dP-sD;<  
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public void run() <`}Oi5nW  
{ 1Jjay#  
while(nStartPos < nEndPos && !bStop) ,E<(K8  
{ h,"K+$  
0"#'Z>"  
*F[@lY\p  
try{ VyK[*kyN  
URL url = new URL(sURL); ?#da4W  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {1Z8cV  
httpConnection.setRequestProperty("User-Agent","NetFox"); Dyyf%'\M  
String sProperty = "bytes="+nStartPos+"-"; Wxx?iW ,  
httpConnection.setRequestProperty("RANGE",sProperty); [@(M%  
Utility.log(sProperty); Bvb.N$G  
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InputStream input = httpConnection.getInputStream(); O`<id+rx  
//logResponseHead(httpConnection); G(" S6u  

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byte[] b = new byte[1024]; %ukFn &-2@  
int nRead; n]S DpptM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5[suwaJQ  
{ L|A}A[P  
nStartPos += fileAccessI.write(b,0,nRead); M{w[hV  
//if(nThreadID == 1) `lygJI?H+{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *:L-/Q)i  
} Q8OA{EUtq  
l];w,(u{  
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Utility.log("Thread " + nThreadID + " is over!"); Jr+~'  
bDownOver = true; >>22:JI`  
//nPos = fileAccessI.write (b,0,nRead); kV9S+ME  
} :p%G+q2  
catch(Exception e){e.printStackTrace ();} Y>W$n9d&G2  
} o}O"  
} oe$&X&  
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//打印回应的头信息 $=3&qg"!  
public void logResponseHead(HttpURLConnection con) 7/C,<$Ep  
{ /Y|y0iK  
for(int i=1;;i++) 4I
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{ RrB)u?  
String header=con.getHeaderFieldKey(i); e1ts/@V  
if(header!=null) DO6Tz-%o  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !D#wSeJ  
Utility.log(header+" : "+con.getHeaderField(header)); q=Xda0c  
else ~0/tU#&  
break; jT/}5\  
} tjLp;%6e  
} \A "_|Yg  
" ,k(*  
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public void splitterStop() B6qM0QW  
{ P5;n(E(19  
bStop = true; Q5%$
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} ::?,ZA  
}#'I,?_k  
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} FVY$A=G  
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/* -QPM$  
**FileAccess.java DpA"5RV  
*//文件访问(定位，写) gbf2ty  
package NetFox; ,yPs4',d  
import java.io.*; Z!#n55|  
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public class FileAccessI implements Serializable{ I'sq0
^
  
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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 -!_\4
 
RandomAccessFile oSavedFile; 1=o|[
7  
long nPos; `wGP31Y.  
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^ &UezDTS  
public FileAccessI() throws IOException '2LK(uaU  
{ 0 $Ygt0d  
this("",0); "p Rr>Fa  
} `3wzOMgJ  
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public FileAccessI(String sName,long nPos) throws IOException d;
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{ 7tZvz `\  
oSavedFile = new RandomAccessFile(sName,"rw"); 1V
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this.nPos = nPos; +,8j]<wpo  
oSavedFile.seek(nPos); b\ P6,s'(  
} FR57F(31  
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public synchronized int write(byte[] b,int nStart,int nLen) A5
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{ -9D2aY_>  
int n = -1; c>~q2_}W(  
try{ E8gbm&x*  
oSavedFile.write(b,nStart,nLen); uDe%M  
n = nLen; H0dHW;U<1  
} U<|hIv-&  
catch(IOException e) --D&a;CO}  
{ A,H|c="  
e.printStackTrace (); _0GM!Cny  
} aB
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return n; $4Vpl  
} QXaE2}}P  
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} 3AQu\4+A  
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/* (9!/bX<  
**SiteInfoBean.java *m>XtBw.  
*/ jIvSjlmI  
package NetFox; O,D/&0  
\c1NIuJR  
178u4$# b  
public class SiteInfoBean { _x'?igy  
U@'F9UB`  
3oo Tn-`{  
private String sSiteURL; //Site's URL f+c<|"we  
private String sFilePath; //Saved File's Path ",O}{z  
private String sFileName; //Saved File's Name p?
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private int nSplitter; //Count of Splited Downloading File 5YG%\  
U %,K8u|WH  
<
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public SiteInfoBean() S&q(PI_"  
{//nSplitter的缺省值为5 th4yuDPuA  
//default value of nSplitter is 5 ,ve$bSp  
this("","","",5); Zqp<8M2  
} .a@>1XO  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) XX9u%BZ~  
{ o$XJSz|6  
sSiteURL= sURL; kv8 /UW  
sFilePath = sPath; jI%g!  
sFileName = sName; Q($.s=&l;  
this.nSplitter = nSpiltter; 
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/4xp?Lo:  
v:xfGA nP  
} zZh\e,*  
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public String getSSiteURL() um5n3=K  
{ h ycdk1SN  
return sSiteURL; QPZ|C{Ce  
} :enmMB#%  
? CabVj-r  
OZCbMeB{+J  
public void setSSiteURL(String value) IPTEOA<M[  
{ q\I2lZ  
sSiteURL = value; 9FKowF_8  
} PKK18E}{%^  
%=G*{mK  
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public String getSFilePath() OtsW>L@ O(  
{ "'9[c"Iz  
return sFilePath; dU<qFxW  
} `9>1 w d  
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(Z)F6sZ`8  
public void setSFilePath(String value) 2$@N4  
{ H6Dw5vG"l  
sFilePath = value; ]N#%exBVo  
} 4xl}kmvv  
jjTb:Z=.'  
q"OJF'>w5  
public String getSFileName() }iBFo\vU  
{ #CcC& I :c  
return sFileName; w1q`  
} b$,~S\\c  
>`S $(f  
s<hl>vY_'  
public void setSFileName(String value) i p"LoCE  
{ yr"BeTrS.  
sFileName = value; Q[Xh{B  
} _ !r]**  
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7#G8qh<
 
public int getNSplitter() 8 mFy9{M  
{ <,\Op=$l3I  
return nSplitter; NW AT"  
} L^b /+R#  
6!Z>^'6  
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public void setNSplitter(int nCount) 9cMQ51k)E  
{ hALg5.E{T  
nSplitter = nCount; /ZpwJc`
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} ) Z^b)KAk  
} FcaO-  
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/* W5c?f,  
**Utility.java :IB@@5r1
 
*/ O% }EpIP_  
package NetFox; k __MYb  

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public class Utility { [i 7^a/e  
{%! >0@7  
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public Utility()  |tVWmm^m  
{ c1>:|D7w  
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} ^h^\kW'#  
!8ch&cr)o+  
//线程睡眠 *ke9/hO1i  
public static void sleep(int nSecond) \:[J-ySJ  
{  8-.jf  
try{ X) O9PQ  
Thread.sleep(nSecond); : l&g5  
} A."]6R<  
catch(Exception e) YZllfw$9  
{ //
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e.printStackTrace (); Ku3/xcu:My  
} o / i W%  
} jph"94  
5U[bn=n  
//日志 7~H.\4HB  
public static void log(String sMsg) DM[gjfMXu  
{ 23|R $s>}i  
System.err.println(sMsg); |w)S &+  
} 2n3g!M6~  
[e.@Yx_}  
rfwX:R6,g  
public static void log(int sMsg) ?K>=>bS^h  
{ 'v?"TZ  
System.err.println(sMsg); M s5L7S  
} RX6s[uQ  
} h^aUVuL/  
>/eV4ma"  
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/* y%NZ(Y,v  
**TestMethod.java =T3O;i  
*/ p+7ZGB  
package NetFox; PYPDK*Ie  
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public class TestMethod { iLR^V!  
PEIf)**0N  
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public TestMethod() Sn~h[s_(  
{ ///xx/weblogic60b2_win.exe sY*iR
q  
try{ ]Ac&h aAP  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); W{js9$oJ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Z.x9SEe1t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2,bLEhu  
fileFetch.start(); 6O9?":3;  
} !^m,v19Ds<  
catch(Exception e){e.printStackTrace ();} +w(>UBy-  
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GL-r;  
} P{tH4V23T  
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public static void main(String[] args) ,{rm<M.)  
{ B$)&;Q  
new TestMethod(); JrhDqyk*  
} b
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} V3] Z~@  
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