http断点续传简单实现（java)

/* !.X.tc  
**SiteFileFetch.java i%{X9!*%TX  
*/ .p6+l!"  
package NetFox; 9s$U%F6}  
import java.io.*; &eZfQ2
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import java.net.*; 1cJsj  
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public class SiteFileFetch extends Thread { V64L,u#`
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SiteInfoBean siteInfoBean = null; //文件信息Bean )mcEQ-!b  
long[] nStartPos; //开始位置 fys  
long[] nEndPos; //结束位置 MXh "Y*}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^HA %q8| n  
long nFileLength; //文件长度 X]*QUV]i  
boolean bFirst = true; //是否第一次取文件 VM=+afY5M  
boolean bStop = false; //停止标志 oR#:NtX
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File tmpFile; //文件下载的临时信息 o4^Fo p  
DataOutputStream output; //输出到文件的输出流 @e2}BhB2  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） 12`_;[37  
public SiteFileFetch(SiteInfoBean bean) throws IOException v> z@  
{ \ZXLX'-  
siteInfoBean = bean; 7*H:Ob)9k  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); e;95a  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); SAv<&  
if(tmpFile.exists ()) `k{& /]  
{ \c`oy=qY0  
bFirst = false; omX?Bl  
read_nPos(); 8\ha@&p  
} ]o/|na*  
else o>D  
{ 3/6/G}s  
nStartPos = new long[bean.getNSplitter()]; A2H4k|8  
nEndPos = new long[bean.getNSplitter()]; g[z.*y/  
}  -7]Xjb5  
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} # '|'r+  
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public void run() A7XnHPIw  
{ H}0dd"  
//获得文件长度 u=+q$Q]  
//分割文件 c9Es%@]  
//实例FileSplitterFetch ,d,\-x-+/  
//启动FileSplitterFetch线程 f^Bc  
//等待子线程返回 dfj\RIV8  
try{ MQ/ A]EeL  
if(bFirst) adEJk  
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nFileLength = getFileSize(); I*[tMzE  
if(nFileLength == -1) &~DTZgY  
{ Z'v-F^  
System.err.println("File Length is not known!"); T6#"8qz<  
} B7*}c]^6
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else if(nFileLength == -2) Z0,~V  
{ d.<~&.-$  
System.err.println("File is not access!"); vq'c@yw;  
} UH`hOJ?  
else ?:rx1}:F  
{ QP I+y8N=  
for(int i=0;i<nStartPos.length;i++) :Og:v#r8=  
{ u62)QJE  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -#&kYK#Ph  
} ,t$,idcT+
 
for(int i=0;i<nEndPos.length-1;i++) bMoAD.}  
{ d}I(`%%)  
nEndPos = nStartPos[i+1]; (zo^Nn9VJ  
} b B  
nEndPos[nEndPos.length-1] = nFileLength; !cEG}(|h  
} $A\m>*@  
} ekSY~z=/u  
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//启动子线程 f`<FT'A  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b%(6EiUA  
for(int i=0;i<nStartPos.length;i++) l0]
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{ ;.
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fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), WT3gNNx|  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $\
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nStartPos,nEndPos,i); LX+5|u  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;-mdi/*g  
fileSplitterFetch.start(); 1'w:`/_  
} &R-H"kK?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), " BTE  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); F
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// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %oykcf,#  
nEndPos = " + nFileLength); p QE)p  
// fileSplitterFetch[nPos.length-1].start(); P @%.`8  
 NY  
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//等待子线程结束 YrI|gz)  
//int count = 0; US&B!Q:v  
//是否结束while循环 5CYo7mJ6+  
boolean breakWhile = false; 43:t \  
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while(!bStop) Do-^S:.  
{ {
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write_nPos(); 1cN')"  
Utility.sleep(500); `vk0c  
breakWhile = true; 7G2PMe;$m  
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for(int i=0;i<nStartPos.length;i++) =J'P.  
{ Qu*1g(el!o  
if(!fileSplitterFetch.bDownOver) <EX7WA  
{ - Xupq/[,  
breakWhile = false; Rhgj&4  
break; Ibr%d2yS=  
} b}
z
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} .#6MQJ]OH  
if(breakWhile) w; TkkDH  
break; NC23Z0y  
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//count++; &K%aw  
//if(count>4) $< %B#axL  
// siteStop(); R'K/t|MC  
} eBr4O i  
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System.err.println("文件下载结束！"); `x8Bn"  
} 8QgA@y"  
catch(Exception e){e.printStackTrace ();} xh9qg0d  
} %|Qw9sbd  
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//获得文件长度 u:P~j  
public long getFileSize() _kraMQ>  
{ !>.vh]8g  
int nFileLength = -1; nS.G~c|  
try{ 7!V@/S}7  
URL url = new URL(siteInfoBean.getSSiteURL()); d.F)9h]XHO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ?Hz2-Cn  
httpConnection.setRequestProperty("User-Agent","NetFox");
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, |E$'  
int responseCode=httpConnection.getResponseCode(); t%0?N<9YkU  
if(responseCode>=400) |Ur"za;%@  
{ >9K//co"of  
processErrorCode(responseCode); n]? WCG}cd  
return -2; //-2 represent access is error 0&w0aP`Y  
} }p3b#fAr  
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String sHeader; _^!vCa7f  
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for(int i=1;;i++) 4
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{ dSK0h(8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); u=K2Q4  
//Utility.log(in.readLine()); I44s(G1jl  
sHeader=httpConnection.getHeaderFieldKey(i); )/t6" "  
if(sHeader!=null) 440FhDMj  
{ pWaPC/,g  
if(sHeader.equals("Content-Length")) *o?i:LE]  
{ Fz"ff4Bx [  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pa/9
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break; #gZ|T M/h  
} C3;[e0.1b  
} UZxmhsv  
else GrI&?=S^  
break; ocA]M=3~k  
} nYw\'c  
} f=:.BR{  
catch(IOException e){e.printStackTrace ();} 5~VosUpe7  
catch(Exception e){e.printStackTrace ();} fj']?a!m  
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Utility.log(nFileLength); QApyP CH  
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return nFileLength; R{}qK r  
} :=.*I  
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//保存下载信息（文件指针位置） p8>%Mflf  
private void write_nPos() EA0iYzV  
{ fEqC] *s  
try{ ohZx03  
output = new DataOutputStream(new FileOutputStream(tmpFile)); x7ATI[b[  
output.writeInt(nStartPos.length); ?S`>>^  
for(int i=0;i<nStartPos.length;i++) aC\4}i<  
{ NB)t7/Us  
// output.writeLong(nPos); :=!Mh}i  
output.writeLong(fileSplitterFetch.nStartPos); y?:dE.5p|  
output.writeLong(fileSplitterFetch.nEndPos); YMzBAf  
} /^<en(0=P  
output.close(); #BJ\{"b_}z  
} ,)#.a%EK
A  
catch(IOException e){e.printStackTrace ();} ;;#nV$  
catch(Exception e){e.printStackTrace ();} o0Gx%99'  
} ;sQbn|=e"  
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>;lKLGJrd>  
//读取保存的下载信息（文件指针位置） zG% |0  
private void read_nPos() vA>W9OI 
 
{ 8F6h#%9  
try{ {8CWWfHCD  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &=w|vB)(p  
int nCount = input.readInt(); UzQ$B>f  
nStartPos = new long[nCount]; ;h=S7M9.  
nEndPos = new long[nCount]; (_8#YyW#  
for(int i=0;i<nStartPos.length;i++) sBjXE>_#)  
{ 8&(-8  
nStartPos = input.readLong(); 4XG]z_+I  
nEndPos = input.readLong(); $h[Yzl  
} d6b.z
P  
input.close(); ^Q2ZqAf^a  
} x:-`o_Q*i  
catch(IOException e){e.printStackTrace ();} (V9h2g&8L  
catch(Exception e){e.printStackTrace ();} gxM[V>[  
} mK\aI  
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private void processErrorCode(int nErrorCode) c E76L%O  
{ > V%Q O>C  
System.err.println("Error Code : " + nErrorCode); qi\n]I  
} n7iE8SK|k  
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//停止文件下载 l>Av5g)  
public void siteStop() wRbw
  
{ .TN2s\:]jw  
bStop = true; ua#K>sur.  
for(int i=0;i<nStartPos.length;i++) fv?45f  
fileSplitterFetch.splitterStop(); R}k69-1vL  
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} Phlk1*1n  
} \(u@F<s-  
//负责部分文件的抓取 mQ,{=C=D  
**FileSplitterFetch.java sp{j!NSL  
*/ `o-*Tr  
package NetFox; 6\`DlUn'*  
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import java.io.*; BE4\U_]a3  
import java.net.*; NbDda/7ki  
uBRw>"c_*8  
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public class FileSplitterFetch extends Thread { C'<'7g4  
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String sURL; //File URL @_O3&ZK  
long nStartPos; //File Snippet Start Position .zwVCW,u  
long nEndPos; //File Snippet End Position ..$>7y}  
int nThreadID; //Thread's ID ?*o;o?5s^  
boolean bDownOver = false; //Downing is over LDX y}hm)  
boolean bStop = false; //Stop identical fLM.kCD?u  
FileAccessI fileAccessI = null; //File Access interface cG
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <G9<"{  
{ m3"c (L`B  
this.sURL = sURL; dqz1xQ1  
this.nStartPos = nStart; E{oB2;P  
this.nEndPos = nEnd; UL
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nThreadID = id; o16~l]Z|f  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 c}cG<F  
} Nh:4ys!P  
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public void run() s((b"{fFb  
{ 1>;6x^_h0S  
while(nStartPos < nEndPos && !bStop) !7Uu]m69n  
{ 24O d]f  
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)<Ob  
try{ |VYr=hjo  
URL url = new URL(sURL); d'q&Lq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `\e'K56W6  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8J^d7uC  
String sProperty = "bytes="+nStartPos+"-"; |rFJ*.nD  
httpConnection.setRequestProperty("RANGE",sProperty); i&pMF O  
Utility.log(sProperty); m9I(TOw  
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InputStream input = httpConnection.getInputStream(); wOM<XhZ  
//logResponseHead(httpConnection); C=s((q*  
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!|(Ao"]
  
byte[] b = new byte[1024]; ULck  
int nRead; oE5;|x3  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9JXhHAxD  
{ K"I{\/x@  
nStartPos += fileAccessI.write(b,0,nRead); D/*vj|  
//if(nThreadID == 1) l`qP~k#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); s)Gb!-``  
} 1"d\
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+>^[W~[2  
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Utility.log("Thread " + nThreadID + " is over!"); $Uy#/MX  
bDownOver = true; % dYI5U89  
//nPos = fileAccessI.write (b,0,nRead);
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} \Qp}|n1JY  
catch(Exception e){e.printStackTrace ();} TftOYY.hQ  
} i(z+a6^@|  
} iPz1eUj  
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//打印回应的头信息 y^, "gD  
public void logResponseHead(HttpURLConnection con) '&/(oJ;O~  
{ EO"=\C,  
for(int i=1;;i++) Px$'(eMj^3  
{ ud.poh~|  
String header=con.getHeaderFieldKey(i); *:(1K%g  
if(header!=null) ?'T"?b<  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); HoMQt3C
 
Utility.log(header+" : "+con.getHeaderField(header)); Qk|( EFQ9  
else ?3n=m%W,J*  
break; tI `w;e%HN  
} "3v7gtGG  
} +6uOg,;  
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public void splitterStop() ^sJ1 ^
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{ 2k%Bl+I  
bStop = true; ADTU{6UPS  
} W;5N04ko  
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} DCz\TwzU  
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/* z/pDOP Ku  
**FileAccess.java Xx=K?Z?3.  
*//文件访问(定位，写) nIG[{gGX  
package NetFox; W&Y4Dq^  
import java.io.*; /95FDk>  
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public class FileAccessI implements Serializable{ }'%$7vL`Ft  
kg zwlKK  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 CzK%x?~]  
RandomAccessFile oSavedFile; :u,2"]  
long nPos; -DA;KWYS  
HW^{;'kH~  
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public FileAccessI() throws IOException o@Dk%LxP  
{ wHq('+{=&  
this("",0); r#ks>s  
} #d3[uF]OmW  
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public FileAccessI(String sName,long nPos) throws IOException *{HGLl|=  
{ *sIi$1vHu  
oSavedFile = new RandomAccessFile(sName,"rw"); h\Z3yAYd  
this.nPos = nPos; c>M_?::)0  
oSavedFile.seek(nPos); 4mki&\lw`  
} >6n@\n  
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public synchronized int write(byte[] b,int nStart,int nLen) x*3@,GmZl  
{ y[TaM9<  
int n = -1; FI80vV7  
try{ n\~"Wim<b  
oSavedFile.write(b,nStart,nLen); }S Y`KoC1  
n = nLen; ag|9$  
} BF@m)w.v  
catch(IOException e) F^4*|g  
{ KB$ vQ@N  
e.printStackTrace (); aMe%#cLI  
} =iA"; x  
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return n; +3(CGNE  
} 6,sRavs  
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} <e@I1iL37y  
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/* &Z#Vw.7U  
**SiteInfoBean.java I$rW[l2  
*/ "i;*\+x  
package NetFox; &e5^v  
oXu~9'm$  
p?EEox  
public class SiteInfoBean { vLVSZX
 
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private String sSiteURL; //Site's URL 0nF>zOmc  
private String sFilePath; //Saved File's Path )AZ`R8-A  
private String sFileName; //Saved File's Name +9&ulr  
private int nSplitter; //Count of Splited Downloading File IFHgD}kp%#  
?,A8
fR  
n=<q3}1Jej  
public SiteInfoBean() 67EDkknt  
{//nSplitter的缺省值为5 oW` *FD  
//default value of nSplitter is 5 B)LXxdkOn  
this("","","",5); /0'fcjOaQ  
} U^W
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@5uyUSt]  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :{e`$kz  
{ .>cL/KaP  
sSiteURL= sURL; * S+7BdP  
sFilePath = sPath; L
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sFileName = sName; >xk:pL*o`  
this.nSplitter = nSpiltter; oQE_?">w  
3M5=@Fwkr  
 Wl}G[>P  
} `pn-fk  
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public String getSSiteURL() #EwRb<'Em  
{ @idp8J [td  
return sSiteURL; O>{t}6o  
} U7f#Z  
60SenHKles  
?N9adL &b  
public void setSSiteURL(String value) l7FZ;%&  
{ YjMbd?v  
sSiteURL = value; jw&}N6^G  
} *AJezhR  
<{P^W;N7  
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public String getSFilePath() n,R[O_9u[  
{ l"V8n BR`  
return sFilePath; D(2kb  
} =h1 QN  
WHh2fN'A5  
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public void setSFilePath(String value) %QlBFl0a  
{ ;U5x'}%0]  
sFilePath = value; Ib<5u  
}
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`XRb:d^  
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public String getSFileName() Qc)RrqYNGF  
{ x#!{5;V&K  
return sFileName; :D)&>{?  
} tue%L]hc  
bU@>1>b6lE  
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public void setSFileName(String value) ~P.-3  
{ 4h0jX9  
sFileName = value; m0q`A5!)  
} W.7d{ @n  
}][|]/s?42  
hwb(W?*  
public int getNSplitter() p{pzOMi6  
{ }<x!95  
return nSplitter; H;"N|pBy  
} #h|,GvmF<b  
lQ(BEv"2G[  
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public void setNSplitter(int nCount) ^?l-YnQqm?  
{ "=0lcbC  
nSplitter = nCount; .$T:n[@  
} lyc{Z%!3  
} E6d8z=X(  
^#6%*(D  
=Z$=-\<x0.  
/* kA9 X!)2w  
**Utility.java z]4g`K+  
*/ sGm(Aax*0  
package NetFox; 6d?2{_},  
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public class Utility { `0i}}Zo  
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public Utility() M%dl?9pbq  
{ 3[g++B."pC  
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} f;; S  
!B38! L  
//线程睡眠 R5~vmT5W  
public static void sleep(int nSecond) jgfP|oD  
{ "rlSK >`  
try{ H<}Fk9  
Thread.sleep(nSecond); X9BBnZ  
} U=<.P;+f9  
catch(Exception e) -W"0,.Dvg  
{ x~Esu}x7  
e.printStackTrace (); i1H80m s  
} F/,<dNJ  
} ;<ma K*f\S  
:{='TMJ7  
//日志 Q)i`.mHfFI  
public static void log(String sMsg) eX),B  
{ b.u8w2(  
System.err.println(sMsg); 2ZIY{lBe  
} jm!C
^5!  
af5`ktx  
/xbF1@XtL  
public static void log(int sMsg) ;.[$  
{ *Z
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System.err.println(sMsg); 8$xKg3-3M  
} GZ>% &^E  
} ^T1-dw(  
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/* zbKW.u]v  
**TestMethod.java (6y3"cbe  
*/ mZJzBYM)  
package NetFox; r{3`
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public class TestMethod { ,$(v#Tz  
v/6,eIz  
CoN/L`.SN  
public TestMethod() z7}zf@Y-qv  
{ ///xx/weblogic60b2_win.exe >Ezwl5b  
try{ Rm1`D  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); U[ungvU1U  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?cxK~Y\  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 1X}Tp\e  
fileFetch.start(); a9_KQ=&CI  
} JBJ7k19;  
catch(Exception e){e.printStackTrace ();} ]O ` [v  
<UL|%9=~  
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} #.t{g8W\C  
Y,"MQFr(o  
NB#*`|qt  
public static void main(String[] args) 2cL)sP}  
{ VYQbyD{V w  
new TestMethod(); 1EPOYvf%U  
} %{_ YJXpO  
} c\ *OId1{;  
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