http断点续传简单实现（java)

/*
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**SiteFileFetch.java a [iC!F2  
*/ uY,&lX+!  
package NetFox; m]+g[L?-  
import java.io.*; Xp
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import java.net.*; ,Zb]3  
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public class SiteFileFetch extends Thread { ATv.3cy  
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SiteInfoBean siteInfoBean = null; //文件信息Bean d90B15]gv  
long[] nStartPos; //开始位置 M&~3fRb4  
long[] nEndPos; //结束位置 Z[yQKy  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 pN&5vu30  
long nFileLength; //文件长度 &p^S6h  
boolean bFirst = true; //是否第一次取文件 N't*eCi  
boolean bStop = false; //停止标志 kz(%8qi8&  
File tmpFile; //文件下载的临时信息 S`BLwnU`#  
DataOutputStream output; //输出到文件的输出流 +eZR._&0  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） f[HhLAVGK`  
public SiteFileFetch(SiteInfoBean bean) throws IOException ddmTMfH  
{ z"u4t.KpL  
siteInfoBean = bean; mZDrvTI'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [7ZFxr\:!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 9;k_"@A6  
if(tmpFile.exists ()) l!<Nw8+U  
{ E#`=xg  
bFirst = false; {^1GHU  
read_nPos(); \Q|1I  
} G@oY2sM"  
else 3aQWzEnh  
{ @>_`g=  
nStartPos = new long[bean.getNSplitter()]; h)"PPI  
nEndPos = new long[bean.getNSplitter()]; @H"~/m_o  
} j~(rG^T  
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} q%w\UAqA  
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public void run() DKAqQ?fS  
{ "D'A7DA  
//获得文件长度 K3$83%E  
//分割文件 z*.
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//实例FileSplitterFetch #Sr_PEo _  
//启动FileSplitterFetch线程 XL>cTM  
//等待子线程返回 T
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try{ IExo#\0'6  
if(bFirst) SEq_37  
{ -~~"}u  
nFileLength = getFileSize(); -tAdA2?G  
if(nFileLength == -1) mVg-z~44T  
{ <LIL{g0eX  
System.err.println("File Length is not known!"); UJ1iXV[h"  
} hW
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else if(nFileLength == -2) V~tq _  
{ 1hw1AJ}(F  
System.err.println("File is not access!"); aB;syl{  
} Q>] iRx>MZ  
else {1;j1|CI  
{ .i>; ?(GH  
for(int i=0;i<nStartPos.length;i++) dkt'~  
{ Mf Dna>,Y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); w,cfSF;=tC  
} .8S6;xnkC  
for(int i=0;i<nEndPos.length-1;i++) E%t_17,=j  
{ im_WTZz2P  
nEndPos = nStartPos[i+1]; Jiyt,D*wX  
} m{  .'55  
nEndPos[nEndPos.length-1] = nFileLength; (ec?_N0=  
} abh='5H|^|  
} 7"Sw))H|  
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//启动子线程 :^tw!U%y1  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; j-8v$0'  
for(int i=0;i<nStartPos.length;i++) M>VT$!Lx  
{ 0W<:3+|n4  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N@lTn}U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), LFvKF.  
nStartPos,nEndPos,i); zs<W>
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Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (=}cc  
fileSplitterFetch.start(); Mo\LFxx>4{  
} v=
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// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 9>\P]:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); fNNkc[YTZI  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^I=c]D]);  
nEndPos = " + nFileLength); !qsk;Vk7Z  
// fileSplitterFetch[nPos.length-1].start(); ?Y7'OlO  
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//等待子线程结束 Y u\
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//int count = 0; la:i!qAH  
//是否结束while循环 D7H,49#1Q  
boolean breakWhile = false;
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while(!bStop) =p,+a/*  
{ rVgz+'rFD[  
write_nPos(); aT1T.3 a  
Utility.sleep(500); 9otA5I^v  
breakWhile = true; wegu1Ny  
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for(int i=0;i<nStartPos.length;i++) 2`hc0 IE  
{
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if(!fileSplitterFetch.bDownOver) WPi^;c8  
{ YUU|!A8x  
breakWhile = false; u;\:#721  
break; mX
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} vp@%wxl!:  
} @RGVcfCG)  
if(breakWhile) Y?W"@awE"\  
break; PPSf8-MLW  
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//count++; @ c,KK~{  
//if(count>4) Bf33%I~  
// siteStop(); '2mR;APz  
} WBD e`  
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System.err.println("文件下载结束！"); 7hwl[knyB  
} `##qf@M  
catch(Exception e){e.printStackTrace ();} ~nJcHJ1nb4  
} SQ!wq  
^Yz.,!B[  
5[l9`Cn&A  
//获得文件长度 5ws|4V  
public long getFileSize() 1T:M?N8J  
{ r2A%.bL#  
int nFileLength = -1; I{Hl2?CnI,  
try{ rI34K~ P  
URL url = new URL(siteInfoBean.getSSiteURL()); g&9E>wT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t I}@1  
httpConnection.setRequestProperty("User-Agent","NetFox"); $ZX^JWq  
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int responseCode=httpConnection.getResponseCode(); EOJk7  
if(responseCode>=400) <Y~?G:v6+  
{ fDyFkhc  
processErrorCode(responseCode); \`?#V xz  
return -2; //-2 represent access is error #;FHyKx  
} 2,,zN-9mt  
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String sHeader; U:6 J~  
z d 9Gi5&  
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for(int i=1;;i++) oD_'8G}  
{ YIs(Q
 
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); LLOe  
//Utility.log(in.readLine()); C`OdMM>D  
sHeader=httpConnection.getHeaderFieldKey(i); +:w9K!31-  
if(sHeader!=null) C/dqCUX:  
{ cw#p!mOi~  
if(sHeader.equals("Content-Length")) #tG/{R  
{ N(mhg
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nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2#'{
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break; 7]a6dMh  
} "^~f.N  
} ]t_AXKd  
else EOhUr=5~  
break; j<!rc>)2+L  
} m<005_Z0Q  
} SFKW"cP  
catch(IOException e){e.printStackTrace ();} sAS\-c'6  
catch(Exception e){e.printStackTrace ();} k{Yj!C> #  
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Utility.log(nFileLength); m *8[I  
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return nFileLength; Y~RPspHW  
} LKY4rY!|@d  
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//保存下载信息（文件指针位置） 5~4I.+~8  
private void write_nPos() _={*<E  
{ t`03$&Cx7  
try{ rs2~spN;h  
output = new DataOutputStream(new FileOutputStream(tmpFile)); %stZ'
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output.writeInt(nStartPos.length); a?E]-Zf  
for(int i=0;i<nStartPos.length;i++) ?sDm~]Z  
{ yd5r]6ej  
// output.writeLong(nPos); 2?rg&og6  
output.writeLong(fileSplitterFetch.nStartPos); 3toY#!1Ch  
output.writeLong(fileSplitterFetch.nEndPos); a9Lf_/w{&  
} `7}6
  
output.close(); VcIsAK".4[  
} NS6Bi3~  
catch(IOException e){e.printStackTrace ();} s@ m A\  
catch(Exception e){e.printStackTrace ();} #wbaRx@rc  
} 5+:b#B  
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//读取保存的下载信息（文件指针位置） UZMo(rG.]{  
private void read_nPos() [ivz/r(Rj  
{ '(Uyju=  
try{ g1
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DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,XCC#F(d1  
int nCount = input.readInt(); 7J./SBhB  
nStartPos = new long[nCount]; neJNMdv@T  
nEndPos = new long[nCount]; L7_Mg{  
for(int i=0;i<nStartPos.length;i++) CjORL'3  
{ :2Qm*Y&_$V  
nStartPos = input.readLong(); `23&vGk}  
nEndPos = input.readLong(); )y'`C@ijI  
} r vVU5zA4H  
input.close(); ~-lIOQ.v  
} A2qus$  
catch(IOException e){e.printStackTrace ();} z|F>+6l"Y7  
catch(Exception e){e.printStackTrace ();} |M`B  
} rAIX(2@cR_  
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private void processErrorCode(int nErrorCode) Bo.x  
{ xT{qeHeZ9,  
System.err.println("Error Code : " + nErrorCode); )QaI{ z  
} 2{!'L'km  
a+szA};  
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//停止文件下载 's@v'u3  
public void siteStop() [nn/a?Z4S  
{ .\X/o!xC  
bStop = true; :aLShxKA  
for(int i=0;i<nStartPos.length;i++) gWqmK/.U.0  
fileSplitterFetch.splitterStop(); )Ac8'{Tq/  
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} e'(n ^_$nl  
} }lML..(
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//负责部分文件的抓取 7'7bIaJk  
**FileSplitterFetch.java 3l->$R]  
*/ kI]i,v#F  
package NetFox; 5&v'aiWK  
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import java.io.*; *58
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import java.net.*; @jN!j*Y H  
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public class FileSplitterFetch extends Thread { Thn-8DT  
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String sURL; //File URL *'`ByS  
long nStartPos; //File Snippet Start Position ,~X^8oY  
long nEndPos; //File Snippet End Position V!3G\*$?  
int nThreadID; //Thread's ID M3K+;-n^  
boolean bDownOver = false; //Downing is over R}llj$?  
boolean bStop = false; //Stop identical &\. LhOm  
FileAccessI fileAccessI = null; //File Access interface 3ypB~bNw  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException dwv xV$Nt  
{ #p&iH9c_  
this.sURL = sURL; 91E!4t
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this.nStartPos = nStart; e%`gD*8  
this.nEndPos = nEnd; VvSD&r^qI  
nThreadID = id; })T}e7>T  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ]2QZ47  
} o B_c6]K  
3%{XJV  
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public void run() }C"EkT!F  
{ 60[f- 0X  
while(nStartPos < nEndPos && !bStop) 8xDSeXh;  
{ jkQv cU  
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try{ U&C\5N]  
URL url = new URL(sURL); gdSv)(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cInzwdh7  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8UwL%"?YB  
String sProperty = "bytes="+nStartPos+"-"; jMcCu
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httpConnection.setRequestProperty("RANGE",sProperty); f";70}_  
Utility.log(sProperty); ,8;;#XR3  
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InputStream input = httpConnection.getInputStream(); 7`6n]4e  
//logResponseHead(httpConnection); J^hj R%H  
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byte[] b = new byte[1024]; ZL#4X*zT  
int nRead; \s`'3y  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) G2ZF`WQ  
{ %N|7<n<S  
nStartPos += fileAccessI.write(b,0,nRead); }%| (G[  
//if(nThreadID == 1) yb*SD!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7 '2E-#^  
} 0h^upB#p  
w?Nvm?_]  
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Utility.log("Thread " + nThreadID + " is over!"); cm%QV?  
bDownOver = true; Q {3"&  
//nPos = fileAccessI.write (b,0,nRead); @'?<92A  
} $f_;>f2N  
catch(Exception e){e.printStackTrace ();} *hF5cM[  
} McNj TD  
} vs{i2!^  
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^.mQ~F  
//打印回应的头信息 <6mXlK3N0  
public void logResponseHead(HttpURLConnection con) A{: a kK  
{ Z=z'j8z3  
for(int i=1;;i++) |08tQ  
{ QVL92"  
String header=con.getHeaderFieldKey(i); |bi"J;y  
if(header!=null) 09_3`K.*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); !R//"{k0?  
Utility.log(header+" : "+con.getHeaderField(header)); r5(OH3  
else `dMOBYV  
break; g`y >)N/  
} }LM^>M%  
} (5_l7hWY  
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public void splitterStop() NlU:e}zG
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{ 16keCG\  
bStop = true; J}i$ny_3OB  
} rxI?|}4  
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} Wgq*|teW  
"}\z7^.W>  
-[~{c]/c  
/* @_FL,AC&m  
**FileAccess.java ykRKZYfsw(  
*//文件访问(定位，写) 4^w>An6  
package NetFox; RB\>$D  
import java.io.*; bG^E]
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public class FileAccessI implements Serializable{ LdU, 32  
wQ2'%T|t  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 JR$Dp&]I  
RandomAccessFile oSavedFile; )qn =  
long nPos; NrgN{6u;  
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public FileAccessI() throws IOException 7_E+y$i=  
{ 6^mO<nB   
this("",0); HMgZ&
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} ?qHW"0Tjn  
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public FileAccessI(String sName,long nPos) throws IOException 'iXjt MX  
{ .<u<!fL2  
oSavedFile = new RandomAccessFile(sName,"rw"); _66zXfM<  
this.nPos = nPos; =k2+VI  
oSavedFile.seek(nPos); zIH[ :  
} d7It}7@9  
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bNevHKS  
public synchronized int write(byte[] b,int nStart,int nLen) X~P0Q  
{ Z#
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int n = -1; cGsP0LkHC  
try{ qOZc}J0  
oSavedFile.write(b,nStart,nLen); ^(N+s?  
n = nLen; 5EFow-AH  
} 4D$$KSa  
catch(IOException e) ~)tMR9=wX  
{ @2CYv>  
e.printStackTrace (); 7T_g?!sdMh  
} x\3 ` W  
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return n; > :!faWX  
} #
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} E0ud<'3<  
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#
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/* QMy;?,  
**SiteInfoBean.java *ErTDy(   
*/ fS1N(RZ1  
package NetFox; y"cK@sOo  
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public class SiteInfoBean { #8;^ys1f  
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private String sSiteURL; //Site's URL y<BiR@%,7  
private String sFilePath; //Saved File's Path A{x&5yX8  
private String sFileName; //Saved File's Name kQ.atr`?e  
private int nSplitter; //Count of Splited Downloading File EVgn^,  
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public SiteInfoBean() rU<  H7U  
{//nSplitter的缺省值为5 r$k *:A$%  
//default value of nSplitter is 5 o$d;
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this("","","",5); y\5V(Q\  
} S,G=MI"  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) XLqS{r~?  
{ `q7I;w+g  
sSiteURL= sURL; 9@QP?=\Y  
sFilePath = sPath; 1_7x'5GdA  
sFileName = sName; TjD`<k  
this.nSplitter = nSpiltter; |oSyyDYWP  
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} $aE%W? \  
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public String getSSiteURL() 4{CVBowi  
{ hAG++
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return sSiteURL; ~;UK/OZ  
} )uwpeq$j7l  
{* >$aI  
^5=}Y>EJO  
public void setSSiteURL(String value) 0J@)?,V-.  
{ k W/3 Aq7r  
sSiteURL = value; ORcl=Eo>  
} tq<7BO<6  
W>wE8? _,  
6/nhz6=  
public String getSFilePath() <G2;nvRr  
{ S$BwOx3QF  
return sFilePath; uPRusG4!R  
} b]4yFwb  
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public void setSFilePath(String value) e_k1pox]l  
{ fcnbPO0M  
sFilePath = value; a3R#Bg(  
} u;!CQ w/  
7k+UCiu>  
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public String getSFileName() #jA|
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{ |5e/.T$  
return sFileName; kSB)}q6a  
} L)8;96  
?*[t'D9f-  
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public void setSFileName(String value) 9Hlu%R  
{ Q&`$:h.~  
sFileName = value; LtejLCf/  
} "F"G(ba^  
[K&O]s<Y  
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public int getNSplitter() 8*>6+"w  
{ RUX!(Xw  
return nSplitter; h!yF  
} 7" Dw4}T  
FT`y3~
 
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public void setNSplitter(int nCount) -Zocu<Rs  
{ 2x$\vL0  
nSplitter = nCount; (tyo4Tz1  
} (V{bfDu&h@  
} r{>tTJFD(:  
>/5D/}4  
il5WLi;{  
/* 3_^w/-7`B  
**Utility.java 5T8X2fS:  
*/ 1tQZyHc42;  
package NetFox; #3kR}Amow  
2}~1poyi>  
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public class Utility { `j_R ?mY  
gOgG23 x  
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public Utility() Zm&Zz^s  
{ 8{%/!ylJz  
N7+K$)3  
0)k%nIhj  
} 4?jhZLBU  
OaU} 9&  
//线程睡眠 `!!A;G7Qg  
public static void sleep(int nSecond) h^x7[qe  
{ <adu^5BI  
try{ .?!{.D  
Thread.sleep(nSecond); g@B9i=  
} #\%GrtM  
catch(Exception e) t~sW]<qjp  
{ MT
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e.printStackTrace (); s![=F}ck  
} 5A~w_p*}  
} {\C$Bz  
/YUf('b  
//日志 x9-K}s]%  
public static void log(String sMsg) wnt^WW=a[  
{ 5XFhjVmEL  
System.err.println(sMsg); (Clf]\_II  
} k(%RX_]C  
Yk?uxZ4)H  
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public static void log(int sMsg) rLh490
@  
{ ,_\h)R_  
System.err.println(sMsg); <0v'IHlZ8  
} -s:JD
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} sDJ5'ul  
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V&h,v%$  
/* eA{,=,v)  
**TestMethod.java t m5>J)C  
*/ ,2&'8:B  
package NetFox; RDzL@xCcn  
'["Y;/>  
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public class TestMethod { z-krL:A  
[h%_`8z  
{'>X6:  
public TestMethod() 9Ki86  
{ ///xx/weblogic60b2_win.exe .}
Bb :*@  
try{ -cY/M~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q.Z0Q  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); NmOQ7T  
SiteFileFetch fileFetch = new SiteFileFetch(bean); I0Wn?Qq=@  
fileFetch.start(); Haq23K  
} eUF PzioW  
catch(Exception e){e.printStackTrace ();} IQ2<Pinv  
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2S!=2u+7  
} e|+uLbN&;c  
~@itZ,d\  
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public static void main(String[] args) "UVV/&`o  
{ kIXLB!L2b^  
new TestMethod(); ;qG a|`#j  
} LoBKR c2t  
} aL#b8dCy'  
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