http断点续传简单实现（java)

/* d~L`*"/)[  
**SiteFileFetch.java HV:mS*e  
*/ sA18f2  
package NetFox; tT7< V{i4  
import java.io.*; Zf~[4Eeb  
import java.net.*; 2u9^ )6/  
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public class SiteFileFetch extends Thread { w)bLdQ  
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SiteInfoBean siteInfoBean = null; //文件信息Bean by*>w/@9)k  
long[] nStartPos; //开始位置 wn*z*  
long[] nEndPos; //结束位置 x?Wt\<|h!  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 UN`F|~@v  
long nFileLength; //文件长度 COS(pfC  
boolean bFirst = true; //是否第一次取文件 ejj|l   
boolean bStop = false; //停止标志 >:l;W4j  
File tmpFile; //文件下载的临时信息 oo\0X  
DataOutputStream output; //输出到文件的输出流 j7;v'eA`;7  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） f.
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public SiteFileFetch(SiteInfoBean bean) throws IOException T-7'#uB.m  
{ 3Rid1;L0U  
siteInfoBean = bean; y<YVb@O.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); AYHfe#!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); sPNX)  
if(tmpFile.exists ()) DbSl}N;  
{ 4-q7o]%5<  
bFirst = false; Uo{h. .7?  
read_nPos(); _]E ~ci}  
} # k+Ggw  
else VQHJO I  
{ 9GnNL I{  
nStartPos = new long[bean.getNSplitter()]; riI0k{  
nEndPos = new long[bean.getNSplitter()]; +Ux)m4}j  
} NLDmZr
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} @+",f]  
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public void run() 9GS<d.#Nvc  
{ %hU8ycI*h  
//获得文件长度 7BCCQsz<  
//分割文件 qF6
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//实例FileSplitterFetch b2 ~~!C  
//启动FileSplitterFetch线程 y(|6`  
//等待子线程返回 G
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try{ <!:,(V>F(C  
if(bFirst) 8k'UEf`'(  
{ -@ #b<"1  
nFileLength = getFileSize(); <[xxCW(2  
if(nFileLength == -1) GY4:9Lub7  
{ &Pt|  
System.err.println("File Length is not known!"); EWN$ILdD  
} .<v0y"amJ  
else if(nFileLength == -2) ToJV.AdfT  
{ Ygn"7  
System.err.println("File is not access!"); 2F-!SI  
} x]%e_  
else 84P^7[YX>  
{ h$ M+Yo+  
for(int i=0;i<nStartPos.length;i++) "}DuAs  
{ JGIN<J85e  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~\hA-l36  
} k%QhF]  
for(int i=0;i<nEndPos.length-1;i++) t~p9iGX<  
{ zW%-Z6%D  
nEndPos = nStartPos[i+1]; tklU zv  
} JGZ,5RTq4-  
nEndPos[nEndPos.length-1] = nFileLength; _,b%t1v  
} 7dX1.}M<(  
} 3y>
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u*[,W-R&  
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//启动子线程 }M f}gCEW  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; I"3Qdi  
for(int i=0;i<nStartPos.length;i++) H;,cUb  
{ 5(>m=ef"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,*0>CBJvv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), xk86?2b{)  
nStartPos,nEndPos,i); mKZ?H$E%%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EA75 D&>I  
fileSplitterFetch.start(); _6qf>=qQ`"  
} BW:&AP@B  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8E/$nRfOd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); AEK* w4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [8Ub#<]]  
nEndPos = " + nFileLength); [w~teX0!  
// fileSplitterFetch[nPos.length-1].start(); N;D(_:^  
OM]p"Jd  
q=bJ9iJsq  
//等待子线程结束 <(d^2-0  
//int count = 0; oypq3V=5  
//是否结束while循环 XPzwT2_E  
boolean breakWhile = false; =,-80WNsX  
".v9#|  
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while(!bStop) .x6*9z#q  
{ +n9&q#ah  
write_nPos(); +d\"n  
Utility.sleep(500); 1SkGG0 W  
breakWhile = true; jD_(im5  
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for(int i=0;i<nStartPos.length;i++) KBzEEvx/$  
{ 6luCi$bL  
if(!fileSplitterFetch.bDownOver) {exF"ap  
{ 0$&Z_oJ  
breakWhile = false; \ ;Hj,z\  
break; >?M:oUVDU  
} G#duZNBdc  
} 60~{sk~E  
if(breakWhile) *~4uF  
break; ekI1j%fO  
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(0D0G-r:  
//count++; *|$s0ga C  
//if(count>4) F#4?@W  
// siteStop(); tK{`?NS  
} &Z=}
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System.err.println("文件下载结束！"); }
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} L7n->8Qk  
catch(Exception e){e.printStackTrace ();} !i_5XcH  
} lhQ*;dMj%"  
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//获得文件长度 6$SsdT|8B  
public long getFileSize() ]lQhIf6)k  
{ '4HwS$mW3  
int nFileLength = -1; U@D=.6\B  
try{ w \0=L=J  
URL url = new URL(siteInfoBean.getSSiteURL()); d7Q. 'cyQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,2H5CFX/  
httpConnection.setRequestProperty("User-Agent","NetFox"); OD>-^W t;%  
!
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int responseCode=httpConnection.getResponseCode(); JEY%(UR8  
if(responseCode>=400) 2c0eh-Gf  
{ _}jj>+zA`  
processErrorCode(responseCode); W@"M/<r@/  
return -2; //-2 represent access is error yuFuYo&[?v  
} 1P8$z:|~  
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String sHeader; K+T`'J4  

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for(int i=1;;i++) w'M0Rd]  
{ 'r1&zw(  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |V!A!tB  
//Utility.log(in.readLine()); @H

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sHeader=httpConnection.getHeaderFieldKey(i); b^Rg_,s  
if(sHeader!=null) !6<2JNf  
{ .h~)|"uzW  
if(sHeader.equals("Content-Length")) %<1fj#X8  
{ qcQ`WU{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?/#HTg)!B  
break; 9IMRWtZWT  
} =5dv38  
} K<Yh'RvTD  
else \iowAo$  
break; woR((K] #G  
} Q:_pW<^  
} RG*Nw6A  
catch(IOException e){e.printStackTrace ();} s%4)}w;z  
catch(Exception e){e.printStackTrace ();} !S(jT?'w  
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Utility.log(nFileLength); |r0j>F
 
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return nFileLength; *WMcE$w/D  
} >)#*}JI  
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//保存下载信息（文件指针位置） >@H:+0h-  
private void write_nPos() V7rcnk#  
{ @gxO%@@  
try{ puXJ:yo(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); y"@~5e477$  
output.writeInt(nStartPos.length); [>"qOFCr#:  
for(int i=0;i<nStartPos.length;i++) #B+2qD>E  
{ %HYC-TF#  
// output.writeLong(nPos); I &{dan2  
output.writeLong(fileSplitterFetch.nStartPos); ZP%^.wxC  
output.writeLong(fileSplitterFetch.nEndPos); OY"{XnPZ  
} /jj}.X7yH  
output.close(); )%,bog(x  
} @ULr)&9  
catch(IOException e){e.printStackTrace ();} XHpoaHyx  
catch(Exception e){e.printStackTrace ();} Fzu"&&>0$  
} #+Vvf
  
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//读取保存的下载信息（文件指针位置） 0dIJgKanGP  
private void read_nPos() p[Q
   
{ 1q\U (^  
try{ %gw0^^A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); t~U:{g~  
int nCount = input.readInt(); {'d?vm!r  
nStartPos = new long[nCount]; deeOtco$LT  
nEndPos = new long[nCount]; EO'3;mo,  
for(int i=0;i<nStartPos.length;i++) 3$HFHUMQsk  
{ P?TFX.p7
 
nStartPos = input.readLong(); "me Jn/  
nEndPos = input.readLong(); GueqpEd2  
} I"@5=m5  
input.close(); IK%j+UB  
} H%faRUonz  
catch(IOException e){e.printStackTrace ();} .4KXe"~E  
catch(Exception e){e.printStackTrace ();} ~=0zZTG  
} <7TpC@"/g  
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kk!}mbA_}  
private void processErrorCode(int nErrorCode) 2^qY,dL  
{ 7~|o_T  
System.err.println("Error Code : " + nErrorCode); +8BH%f}X  
} Z#4? /'  
fep#Kb%"e  
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//停止文件下载 &N
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public void siteStop() ~"=nt@M]  
{ vkBngsS  
bStop = true; 37lmB '~  
for(int i=0;i<nStartPos.length;i++) YJ!6)d?C.  
fileSplitterFetch.splitterStop(); oz[E>%  
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} VnIJ$5Y  
} q~l&EH0  
//负责部分文件的抓取 .}CPZ3y  
**FileSplitterFetch.java `7N[rs9|S  
*/ z@i
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package NetFox; B~~rLo:a  
MR+ndB<  
})"9TfC  
import java.io.*;
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import java.net.*; :_H$*Q=1  
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public class FileSplitterFetch extends Thread { Yq;
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String sURL; //File URL @~a52'\  
long nStartPos; //File Snippet Start Position OkFq>;{a  
long nEndPos; //File Snippet End Position pV>/"K  
int nThreadID; //Thread's ID U<#i\4W  
boolean bDownOver = false; //Downing is over < ^J!*>  
boolean bStop = false; //Stop identical q)!{oi{x(  
FileAccessI fileAccessI = null; //File Access interface 6dg[  
NrL%]dl3/  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tk, HvE  
{ 0Y"==g+>f  
this.sURL = sURL; l"ih+%
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this.nStartPos = nStart; yY,.GzIjCj  
this.nEndPos = nEnd; YjG0: 9  
nThreadID = id; l<qxr.X  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 $9ON3>  
} /wvA]ooT  
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public void run() T8qG9)~3  
{ Q7#Q6-Q  
while(nStartPos < nEndPos && !bStop) Ui1K66{  
{ -{P)\5.L  
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try{ ^. Pn)J  
URL url = new URL(sURL); 1 k H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zHu:Ec7  
httpConnection.setRequestProperty("User-Agent","NetFox"); WddU|-W  
String sProperty = "bytes="+nStartPos+"-";  NU_VUd2  
httpConnection.setRequestProperty("RANGE",sProperty); Q$RP2&  
Utility.log(sProperty); h!)(R<  
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InputStream input = httpConnection.getInputStream(); L!e@T'  
//logResponseHead(httpConnection); , :kCt=4%  
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byte[] b = new byte[1024]; Gzm[4|nO^  
int nRead; v_G4:tY  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) gw5CU)r4$  
{ S9xC> |<  
nStartPos += fileAccessI.write(b,0,nRead); r{Fu|aoa;5  
//if(nThreadID == 1) 6|9];)  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); iOD9lR`s  
} wePMBL1P*  
w|$;$a7)  
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Utility.log("Thread " + nThreadID + " is over!"); &=s{ +0  
bDownOver = true; r%xNfTa  
//nPos = fileAccessI.write (b,0,nRead); dn`#N^Od  
} (T`x-wTl  
catch(Exception e){e.printStackTrace ();} k"L_0HK  
} SZyPl9.b  
}  a_Xh(d$  
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//打印回应的头信息 D{G#|&;  
public void logResponseHead(HttpURLConnection con) &os*@0h4  
{ ]n!pn#Q  
for(int i=1;;i++) `d8$OC  
{
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String header=con.getHeaderFieldKey(i); ,,,5pCi\  
if(header!=null) }RM?gE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <Ojf&C^Z  
Utility.log(header+" : "+con.getHeaderField(header)); *9*I:Uh57  
else B|!YGfL  
break; 9$Hgh7'hvs  
} ql_aDoj  
} `Y+p7*Qr2  
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public void splitterStop() %=NqxF>>  
{ u/hD9g~H7K  
bStop = true; AoTL)',  
} O-:~6A  
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} s<^UAdLnl  
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/* LR`/pet  
**FileAccess.java aP4r6lLv+  
*//文件访问(定位，写) N(F9vZOs  
package NetFox; WxI
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import java.io.*; !q$IB?8   
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public class FileAccessI implements Serializable{ k deJB-  
^>]p4Q3 6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @dO~0dF  
RandomAccessFile oSavedFile; u6|7P<HUfb  
long nPos; "esV#%:#J  
iUSs)[]H>  
*UEo&B2+  
public FileAccessI() throws IOException hX[hR  
{ ]l&_Pv!!  
this("",0); YMm Fpy  
} =FdS'<GM  
S* <:He&1  
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public FileAccessI(String sName,long nPos) throws IOException ~9x$tb x-  
{ (8{h I  
oSavedFile = new RandomAccessFile(sName,"rw"); t'7)aJMP  
this.nPos = nPos; ="Dmfy7  
oSavedFile.seek(nPos); n {^D_S  
} ;2&(]1X  
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public synchronized int write(byte[] b,int nStart,int nLen) m-ZVlj  
{ fq\E$'o$  
int n = -1; ?;}2Z)  
try{ &4p:2,|r9  
oSavedFile.write(b,nStart,nLen); {t9'8
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n = nLen; B \[P/AC  
} 5qUyOkI  
catch(IOException e) c 8E&  
{ vE&  
e.printStackTrace (); +vZ-o{}.jO  
} -_A0<A.  
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{fk'g(E8([  
return n; p?5`+Z  
} ~hz]x^:  
.}]5y4UQ.  
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} p6I@o7f  
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/* .y[=0K:  
**SiteInfoBean.java WM*7p
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*/ qDL9  
package NetFox; H@MUzV  
%'@&j2j>  
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public class SiteInfoBean { r@k&1*&  
hb[K.`g  
!=eui$]  
private String sSiteURL; //Site's URL  ;-U:t4  
private String sFilePath; //Saved File's Path c1!h;(&  
private String sFileName; //Saved File's Name F&I^bkvh  
private int nSplitter; //Count of Splited Downloading File # l}Y1^PDd  
Y+j|T`d  
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public SiteInfoBean() q=g;TAXZl  
{//nSplitter的缺省值为5 /R@eOl}D  
//default value of nSplitter is 5 &o:wSe  
this("","","",5); sIg{a(1/  
} bi[vs|  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &5c)qap;n  
{ WVp14Z?k  
sSiteURL= sURL; Tig`4d-%  
sFilePath = sPath; O,XVA  
sFileName = sName; ^%*%=LJm  
this.nSplitter = nSpiltter; yj"+!g  
OG/R6k.  
`3\5&Bf  
} s#64NG  
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public String getSSiteURL() 29 ')Y|$,  
{ Lk=f^qJ ]  
return sSiteURL; E*j)gj9  
} n1!0KOu/N  
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public void setSSiteURL(String value) 'I\bz;VT  
{ '+5*ajP<  
sSiteURL = value; d5UdRX]*  
} 9xN4\y6F  
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G-9]z[\#  
public String getSFilePath() mGwBbY+5n  
{ 7WKb| /#;  
return sFilePath; _}{C?611c  
} .$L'Jt
2X  
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public void setSFilePath(String value) @e3O=_m-  
{ 8v5cQ5Lc  
sFilePath = value; ##EMJ
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} [f&ja[m q  
*Xn{{  
*oKc4S+  
public String getSFileName() b~WiE?  
{ bK<'J=#1  
return sFileName; Mb"i}Yt{  
} gW$X8ECX  
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%F]4)XeW-+  
public void setSFileName(String value) K;k&w; j  
{
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sFileName = value; MXq+aS{  
} \l"1Io=  
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public int getNSplitter() -5\hZ!!J2  
{ ^fQ ]>/u  
return nSplitter; q`{crY30  
} T:q!>"5  
.|G([O^H  
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public void setNSplitter(int nCount) 3#!}W#xv  
{ +.! F]0ju  
nSplitter = nCount; xi %u)p  
} ~C\R!DN,  
} ,Hlbl}.ls  
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/* Lf4c[[@%gd  
**Utility.java jO&sS?  
*/ I'Ui` :A  
package NetFox; -iLp3m<ai  
-hZlFAZi  
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public class Utility { A9`& Wnw?  
2"cUBFc1I  
@!1o +x  
public Utility() PJ5~,4H-4  
{ Z@4BTA  
'avzESe~'  
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} *9Ej fs7L  
:7
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//线程睡眠 Bvk 8b  
public static void sleep(int nSecond) s{#rCc)  
{ P+tRxpz  
try{ +*Y/+.4WE$  
Thread.sleep(nSecond);
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} IH(]RHTp%  
catch(Exception e) F%Oy4*4  
{ yr8 b?m.x  
e.printStackTrace (); &66-0d+Sh  
} !YYI{BJ7:N  
} He @d~9M  
#&u9z5ywM  
//日志 ~4IkQ|,  
public static void log(String sMsg) o/I'Qi$v-  
{ Q"itV&d
,  
System.err.println(sMsg); &Azfpv  
} + :4 F@R  
%#kml{I   
kG 7]<^Os3  
public static void log(int sMsg) =BW;n]ls  
{ $o2H#"  
System.err.println(sMsg); 6b`3AAGU"  
} eb&#sZ  
} olda't  
,/*L|M/&5  
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/* %P@V7n  
**TestMethod.java *|n-Hr  
*/ !:"$1kh1("  
package NetFox; WD.td  
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public class TestMethod { jRdmQmTJ  
h]WPWa)M  
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public TestMethod() sa6/$  
{ ///xx/weblogic60b2_win.exe 4
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try{ 7-S?\:J  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); jMFLd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); m ioNMDG  
SiteFileFetch fileFetch = new SiteFileFetch(bean); rnX D(  
fileFetch.start(); dA4DW  
} &/wd_;d^A  
catch(Exception e){e.printStackTrace ();} 0G?*i_u\  
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@s7ZfV??  
} N(ov.l;  
[9N
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!C]2:+z-MF  
public static void main(String[] args) P)D2PVD  
{ X0\O3l*j  
new TestMethod(); LKC^Y)6o  
} $?`-} wY  
} }KFf  
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